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  25 
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 356    <!ELEMENT li  ANY>
 357  ]>
 358 
 359 <specification label="JVM(TM) Tool Interface">
 360   <title subtitle="Version">
 361     <tm>JVM</tm> Tool Interface
 362   </title>
 363 
 364   <intro id="whatIs" label="What is the JVM Tool Interface?">
 365     The <tm>JVM</tm> Tool Interface (<jvmti/>)
 366     is a programming interface used by development and monitoring tools.
 367     It provides both a way to inspect the state and
 368     to control the execution of applications running in the
 369     <tm>Java</tm> virtual machine (VM).
 370     <p/>
 371     <jvmti/> is intended to provide a VM interface for the full breadth of tools
 372     that need access to VM state, including but not limited to: profiling,
 373     debugging, monitoring, thread analysis, and coverage analysis tools.
 374     <p/>
 375     <jvmti/> may not be available in all implementations of the <tm>Java</tm> virtual
 376     machine.
 377     <p/>
 378     <jvmti/> is a two-way interface.
 379     A client of <jvmti/>, hereafter called an <i>agent</i>,
 380     can be notified of
 381     interesting occurrences through <internallink id="EventSection">events</internallink>.
 382     <jvmti/>
 383     can query and control the application through many
 384     <internallink id="FunctionSection">functions</internallink>,
 385     either in response to events or
 386     independent of them.
 387     <p/>
 388     Agents run in the same process with and communicate directly with
 389     the virtual machine executing
 390     the application being examined.  This communication is
 391     through a native interface (<jvmti/>). The native in-process interface allows
 392     maximal control with minimal intrusion on the part of a tool.
 393     Typically, agents are relatively compact. They can be controlled
 394     by a separate process which implements the bulk of a tool's
 395     function without interfering with the target application's normal execution.
 396   </intro>
 397 
 398   <intro id="architecture" label="Architecture">
 399     Tools can be written directly to <jvmti/> or indirectly
 400     through higher level interfaces.
 401     The Java Platform Debugger Architecture includes <jvmti/>, but also
 402     contains higher-level, out-of-process debugger interfaces. The higher-level
 403     interfaces are more appropriate than <jvmti/> for many tools.
 404     For more information on the Java Platform Debugger Architecture,
 405     see the
 406     <externallink id="jpda/architecture.html">Java
 407       Platform Debugger Architecture website</externallink>.
 408   </intro>
 409 
 410   <intro id="writingAgents" label="Writing Agents">
 411     Agents can be written in any native language that supports C
 412     language calling conventions and C or C++
 413     definitions.
 414     <p/>
 415     The function, event, data type, and constant definitions needed for
 416     using <jvmti/> are defined in the include file <code>jvmti.h</code>.
 417     To use these definitions add the <tm>J2SE</tm> include directory
 418     to your include path and add
 419     <example>
 420 #include &lt;jvmti.h&gt;
 421     </example>
 422     to your source code.
 423   </intro>
 424 
 425   <intro id="deployingAgents" label="Deploying Agents">
 426     An agent is deployed in a platform specific manner but is typically the
 427     platform equivalent of a dynamic library. On the <tm>Windows</tm> operating
 428     system, for example, an agent library is a "Dynamic Linked Library" (DLL).
 429     On the <tm>Solaris</tm> Operating Environment, an agent library is a shared
 430     object (<code>.so</code> file).
 431     <p/>
 432 
 433     An agent may be started at VM startup by specifying the agent library
 434     name using a <internallink id="starting">command line option</internallink>.
 435     Some implementations may support a mechanism to <internallink id="onattach">
 436     start agents</internallink> in the live <functionlink id="GetPhase">phase</functionlink>.
 437     The details of how this is initiated are implementation specific.
 438   </intro>
 439 
 440     <intro id="entryPoint" label="Statically Linked Agents (since version 1.2.3)">
 441 
 442       A native JVMTI Agent may be <i>statically linked</i> with the VM.
 443       The manner in which the library and VM image are combined is
 444       implementation-dependent.
 445       An agent L whose image has been combined with the VM is defined as
 446       <i>statically linked</i> if and only if the agent exports a function
 447       called Agent_OnLoad_L.
 448 <p/>
 449       If a <i>statically linked</i> agent L exports a function called
 450       Agent_OnLoad_L and a function called Agent_OnLoad, the Agent_OnLoad
 451       function will be ignored.
 452       If an agent L is <i>statically linked</i>, an Agent_OnLoad_L
 453       function will be invoked with the same arguments and expected return
 454       value as specified for the Agent_OnLoad function.
 455       An agent L that is <i>statically linked</i> will prohibit an agent of
 456       the same name from being loaded dynamically.
 457 <p/>
 458       The VM will invoke the Agent_OnUnload_L function of the agent, if such
 459       a function is exported, at the same point during VM execution as it would
 460       have called the dynamic entry point Agent_OnUnLoad. A statically loaded
 461       agent cannot be unloaded. The Agent_OnUnload_L function will still be
 462       called to do any other agent shutdown related tasks.
 463       If a <i>statically linked</i> agent L exports a function called
 464       Agent_OnUnLoad_L and a function called Agent_OnUnLoad, the Agent_OnUnLoad
 465       function will be ignored.
 466 <p/>
 467       If an agent L is <i>statically linked</i>, an Agent_OnAttach_L function
 468       will be invoked with the same arguments and expected return value as
 469       specified for the Agent_OnAttach function.
 470       If a <i>statically linked</i> agent L exports a function called
 471       Agent_OnAttach_L and a function called Agent_OnAttach, the Agent_OnAttach
 472       function will be ignored.
 473 </intro>
 474 
 475   <intro id="starting" label="Agent Command Line Options">
 476     The term "command-line option" is used below to
 477     mean options supplied in the <code>JavaVMInitArgs</code> argument
 478     to the <code>JNI_CreateJavaVM</code> function of the JNI
 479     Invocation API.
 480     <p/>
 481     One of the two following
 482     command-line options is used on VM startup to
 483     properly load and run agents.
 484     These arguments identify the library containing
 485     the agent as well as an options
 486     string to be passed in at startup.
 487     <dl>
 488       <dt><code>-agentlib:</code><i>&lt;agent-lib-name&gt;</i><code>=</code><i>&lt;options&gt;</i></dt>
 489       <dd>
 490         The name following <code>-agentlib:</code> is the name of the
 491         library to load.  Lookup of the library, both its full name and location,
 492         proceeds in a platform-specific manner.
 493         Typically, the <i>&lt;agent-lib-name&gt;</i> is expanded to an
 494         operating system specific file name.
 495         The <i>&lt;options&gt;</i> will be passed to the agent on start-up.
 496         For example, if the option
 497         <code>-agentlib:foo=opt1,opt2</code> is specified, the VM will attempt to
 498         load the shared library <code>foo.dll</code> from the system <code>PATH</code>
 499         under <tm>Windows</tm> or <code>libfoo.so</code> from the
 500         <code>LD_LIBRARY_PATH</code> under the <tm>Solaris</tm> operating
 501         environment.
 502         If the agent library is statically linked into the executable
 503         then no actual loading takes place.
 504     <p/>
 505       </dd>
 506       <dt><code>-agentpath:</code><i>&lt;path-to-agent&gt;</i><code>=</code><i>&lt;options&gt;</i></dt>
 507       <dd>
 508         The path following <code>-agentpath:</code> is the absolute path from which
 509         to load the library.
 510         No library name expansion will occur.
 511         The <i>&lt;options&gt;</i> will be passed to the agent on start-up.
 512         For example, if the option
 513         <code>-agentpath:c:\myLibs\foo.dll=opt1,opt2</code> is specified, the VM will attempt to
 514         load the shared library <code>c:\myLibs\foo.dll</code>. If the agent
 515         library is statically linked into the executable
 516         then no actual loading takes place.
 517     <p/>
 518       </dd>
 519     </dl>
 520     For a dynamic shared library agent, the start-up routine
 521     <internallink id="onload"><code>Agent_OnLoad</code></internallink>
 522     in the library will be invoked. If the agent library is statically linked
 523     into the executable then the system will attempt to invoke the
 524     <code>Agent_OnLoad_&lt;agent-lib-name&gt;</code> entry point where
 525     &lt;agent-lib-name&gt; is the basename of the
 526     agent. In the above example <code>-agentpath:c:\myLibs\foo.dll=opt1,opt2</code>,
 527     the system will attempt to find and call the <code>Agent_OnLoad_foo</code> start-up routine.
 528     <p/>
 529     Libraries loaded with <code>-agentlib:</code> or <code>-agentpath:</code>
 530     will be searched for JNI native method implementations to facilitate the
 531     use of Java programming language code in tools, as is needed for
 532     <internallink id="bci">bytecode instrumentation</internallink>.
 533     <p/>
 534     The agent libraries will be searched after all other libraries have been
 535     searched (agents wishing to override or intercept the native method
 536     implementations of non-agent methods can use the
 537     <eventlink id="NativeMethodBind">NativeMethodBind event</eventlink>).
 538     <p/>
 539     These switches do the above and nothing more - they do not change the
 540     state of the VM or <jvmti/>.  No command line options are needed
 541     to enable <jvmti/>
 542     or aspects of <jvmti/>, this is handled programmatically
 543     by the use of
 544     <internallink id="capability">capabilities</internallink>.
 545   </intro>
 546 
 547   <intro id="startup" label="Agent Start-Up">
 548     The VM starts each agent by invoking a start-up function.
 549     If the agent is started in the <code>OnLoad</code>
 550     <functionlink id="GetPhase">phase</functionlink> the function
 551     <internallink id="onload"><code>Agent_OnLoad</code></internallink>
 552     or <internallink id="onload"><code>Agent_OnLoad_L</code></internallink>
 553     for statically linked agents will be invoked.
 554     If the agent is started in the live
 555     <functionlink id="GetPhase">phase</functionlink> the function
 556     <internallink id="onattach"><code>Agent_OnAttach</code></internallink>
 557     or <internallink id="onattach"><code>Agent_OnAttach_L</code></internallink>
 558     for statically linked agents will be invoked.
 559     Exactly one call to a start-up function is made per agent.
 560   </intro>
 561 
 562   <intro id="onload" label="Agent Start-Up (OnLoad phase)">
 563     If an agent is started during the <code>OnLoad</code> phase then its
 564     agent library must export a start-up function with the following prototype:
 565     <example>
 566 JNIEXPORT jint JNICALL
 567 Agent_OnLoad(JavaVM *vm, char *options, void *reserved)</example>
 568     Or for a statically linked agent named 'L':
 569     <example>
 570 JNIEXPORT jint JNICALL
 571 Agent_OnLoad_L(JavaVM *vm, char *options, void *reserved)</example>
 572 
 573     The VM will start the agent by calling this function.
 574     It will be called early enough in VM initialization that:
 575     <ul>
 576       <li><functionlink id="SetSystemProperty">system properties</functionlink>
 577         may be set before they have been used in the start-up of the VM</li>
 578       <li>the full set of
 579         <internallink id="capability">capabilities</internallink>
 580         is still available (note that capabilities that configure the VM
 581         may only be available at this time--see the
 582         <internallink id="capability">Capability function section</internallink>)</li>
 583       <li>no bytecodes have executed</li>
 584       <li>no classes have been loaded</li>
 585       <li>no objects have been created</li>
 586     </ul>
 587     <p/>
 588     The VM will call the <code>Agent_OnLoad</code> or
 589     <code>Agent_OnLoad_&lt;agent-lib-name&gt;</code> function with
 590     <i>&lt;options&gt;</i> as the second argument -
 591     that is, using the command-line option examples,
 592     <code>"opt1,opt2"</code> will be passed to the <code>char *options</code>
 593     argument of <code>Agent_OnLoad</code>.
 594     The <code>options</code> argument is encoded as a
 595     <internallink id="mUTF">modified UTF-8</internallink> string.
 596     If <i>=&lt;options&gt;</i> is not specified,
 597     a zero length string is passed to <code>options</code>.
 598     The lifespan of the <code>options</code> string is the
 599     <code>Agent_OnLoad</code> or <code>Agent_OnLoad_&lt;agent-lib-name&gt;</code>
 600     call.  If needed beyond this time the string or parts of the string must
 601     be copied.
 602     The period between when <code>Agent_OnLoad</code> is called and when it
 603     returns is called the <i>OnLoad phase</i>.
 604     Since the VM is not initialized during the OnLoad
 605     <functionlink id="GetPhase">phase</functionlink>,
 606     the set of allowed operations
 607     inside <code>Agent_OnLoad</code> is restricted (see the function descriptions for the
 608     functionality available at this time).
 609     The agent can safely process the options and set
 610     event callbacks with <functionlink id="SetEventCallbacks"></functionlink>. Once
 611     the VM initialization event is received
 612     (that is, the <eventlink id="VMInit">VMInit</eventlink>
 613     callback is invoked), the agent
 614     can complete its initialization.
 615     <rationale>
 616       Early startup is required so that agents can set the desired capabilities,
 617       many of which must be set before the VM is initialized.
 618       In JVMDI, the -Xdebug command-line option provided
 619       very coarse-grain control of capabilities.
 620       JVMPI implementations use various tricks to provide a single "JVMPI on" switch.
 621       No reasonable command-line
 622       option could provide the fine-grain of control required to balance needed capabilities vs
 623       performance impact.
 624       Early startup is also needed so that agents can control the execution
 625       environment - modifying the file system and system properties to install
 626       their functionality.
 627     </rationale>
 628     <p/>
 629     The return value from <code>Agent_OnLoad</code> or
 630     <code>Agent_OnLoad_&lt;agent-lib-name&gt;</code> is used to indicate an error.
 631     Any value other than zero indicates an error and causes termination of the VM.
 632   </intro>
 633 
 634   <intro id="onattach" label="Agent Start-Up (Live phase)">
 635     A VM may support a mechanism that allows agents to be started in the VM during the live
 636     <functionlink id="GetPhase">phase</functionlink>. The details of how this is supported,
 637     are implementation specific. For example, a tool may use some platform specific mechanism,
 638     or implementation specific API, to attach to the running VM, and request it start a given
 639     agent.
 640     <p/>
 641     If an agent is started during the live phase then its agent library
 642     must export a start-up function
 643     with the following prototype:
 644     <example>
 645 JNIEXPORT jint JNICALL
 646 Agent_OnAttach(JavaVM* vm, char *options, void *reserved)</example>
 647 Or for a statically linked agent named 'L':
 648     <example>
 649 JNIEXPORT jint JNICALL
 650 Agent_OnAttach_L(JavaVM* vm, char *options, void *reserved)</example>
 651 
 652     <p/>
 653     The VM will start the agent by calling this function.
 654     It will be called in the context of a thread
 655     that is attached to the VM. The first argument <i>&lt;vm&gt;</i> is the Java VM.
 656     The <i>&lt;options&gt;</i> argument is the startup options provided to the agent.
 657     <i>&lt;options&gt;</i> is encoded as a <internallink id="mUTF">modified UTF-8
 658     </internallink> string.
 659     If startup options were not provided, a zero length string is passed to
 660     <code>options</code>. The lifespan of the <code>options</code> string is the
 661     <code>Agent_OnAttach</code> or <code>Agent_OnAttach_&lt;agent-lib-name&gt;</code> call.
 662     If needed beyond this time the string or parts of the string must be copied.
 663     <p/>
 664     Note that some <internallink id="capability">capabilities</internallink>
 665     may not be available in the live phase.
 666     <p/>
 667     The <code>Agent_OnAttach</code> or <code>Agent_OnAttach_&lt;agent-lib-name
 668     &gt;</code> function initializes the agent and returns a value
 669     to the VM to indicate if an error occurred. Any value other than zero indicates an error.
 670     An error does not cause the VM to terminate. Instead the VM ignores the error, or takes
 671     some implementation specific action -- for example it might print an error to standard error,
 672     or record the error in a system log.
 673   </intro>
 674 
 675   <intro id="onunload" label="Agent Shutdown">
 676     The library may optionally export a
 677     shutdown function with the following prototype:
 678     <example>
 679 JNIEXPORT void JNICALL
 680 Agent_OnUnload(JavaVM *vm)</example>
 681     Or for a statically linked agent named 'L':
 682     <example>
 683 JNIEXPORT void JNICALL
 684 Agent_OnUnload_L(JavaVM *vm)</example>
 685 
 686     This function will be called by the VM when the library is about to be unloaded.
 687     The library will be unloaded (unless it is statically linked into the
 688     executable) and this function will be called if some platform specific
 689     mechanism causes the unload (an unload mechanism is not specified in this document)
 690     or the library is (in effect) unloaded by the termination of the VM whether through
 691     normal termination or VM failure, including start-up failure.
 692     Uncontrolled shutdown is, of course, an exception to this rule.
 693     Note the distinction between this function and the
 694     <eventlink id="VMDeath">VM Death event</eventlink>: for the VM Death event
 695     to be sent, the VM must have run at least to the point of initialization and a valid
 696     <jvmti/> environment must exist which has set a callback for VMDeath
 697     and enabled the event.
 698     None of these are required for <code>Agent_OnUnload</code> or
 699     <code>Agent_OnUnload_&lt;agent-lib-name&gt;</code> and this function
 700     is also called if the library is unloaded for other reasons.
 701     In the case that a VM Death event is sent, it will be sent before this
 702     function is called (assuming this function is called due to VM termination).
 703     This function can be used to clean-up resources allocated by the agent.
 704   </intro>
 705 
 706   <intro id="tooloptions" label="JAVA_TOOL_OPTIONS">
 707     Since the command-line cannot always be accessed or modified, for example in embedded VMs
 708     or simply VMs launched deep within scripts, a <code>JAVA_TOOL_OPTIONS</code> variable is
 709     provided so that agents may be launched in these cases.
 710     <p/>
 711     Platforms which support environment variables or other named strings, may support the
 712     <code>JAVA_TOOL_OPTIONS</code> variable.  This variable will be broken into options at white-space
 713     boundaries.  White-space characters include space, tab, carriage-return, new-line,
 714     vertical-tab, and form-feed.  Sequences of white-space characters are considered
 715     equivalent to a single white-space character.  No white-space is included in the options
 716     unless quoted.  Quoting is as follows:
 717     <ul>
 718         <li>All characters enclosed between a pair of single quote marks (''), except a single
 719         quote, are quoted.</li>
 720         <li>Double quote characters have no special meaning inside a pair of single quote marks.</li>
 721         <li>All characters enclosed between a pair of double quote marks (""), except a double
 722         quote, are quoted.</li>
 723         <li>Single quote characters have no special meaning inside a pair of double quote marks.</li>
 724         <li>A quoted part can start or end anywhere in the variable.</li>
 725         <li>White-space characters have no special meaning when quoted -- they are included in
 726         the option like any other character and do not mark white-space boundaries.</li>
 727         <li>The pair of quote marks is not included in the option.</li>
 728     </ul>
 729     <code>JNI_CreateJavaVM</code> (in the JNI Invocation API) will prepend these options to the options supplied
 730     in its <code>JavaVMInitArgs</code> argument. Platforms may disable this feature in cases where security is
 731     a concern; for example, the Reference Implementation disables this feature on Unix systems when
 732     the effective user or group ID differs from the real ID.
 733     This feature is intended to support the initialization of tools -- specifically including the
 734     launching of native or Java programming language agents.  Multiple tools may wish to use this
 735     feature, so the variable should not be overwritten, instead,  options should be appended to
 736     the variable.  Note that since the variable is processed at the time of the JNI Invocation
 737     API create VM call, options processed by a launcher (e.g., VM selection options) will not be handled.
 738   </intro>
 739 
 740   <intro id="environments" label="Environments">
 741     The <jvmti/> specification supports the use of multiple simultaneous
 742     <jvmti/> agents.
 743     Each agent has its own <jvmti/> environment.
 744     That is, the <jvmti/> state is
 745     separate for each agent - changes to one environment do not affect the
 746     others.  The state of a <jvmti/>
 747     environment includes:
 748     <ul>
 749       <li><functionlink id="SetEventCallbacks">the event callbacks</functionlink></li>
 750       <li><functionlink id="SetEventNotificationMode">the set of events which are enabled</functionlink></li>
 751       <li><internallink id="capability">the capabilities</internallink></li>
 752       <li><internallink id="memory">the memory allocation/deallocation hooks</internallink></li>
 753     </ul>
 754     Although their <jvmti/> state
 755     is separate, agents inspect and modify the shared state
 756     of the VM, they also share the native environment in which they execute.
 757     As such, an agent can perturb the results of other agents or cause them
 758     to fail.  It is the responsibility of the agent writer to specify the level
 759     of compatibility with other agents.  <jvmti/> implementations are not capable
 760     of preventing destructive interactions between agents. Techniques to reduce
 761     the likelihood of these occurrences are beyond the scope of this document.
 762     <p/>
 763     An agent creates a <jvmti/> environment
 764     by passing a <jvmti/> version
 765     as the interface ID to the JNI Invocation API function
 766     <externallink id="jni/invocation.html#getenv">
 767       <code>GetEnv</code></externallink>.
 768     See <internallink id="jvmtiEnvAccess">Accessing <jvmti/> Functions</internallink>
 769     for more details on the creation and use of
 770     <jvmti/> environments.
 771     Typically, <jvmti/> environments are created by calling <code>GetEnv</code> from
 772     <internallink id="onload"><code>Agent_OnLoad</code></internallink>.
 773   </intro>
 774 
 775   <intro id="bci" label="Bytecode Instrumentation">
 776     This interface does not include some events that one might expect in an interface with
 777     profiling support.  Some examples include full speed
 778     method enter and exit events.  The interface instead provides support for
 779     <i>bytecode instrumentation</i>, the ability to alter the Java virtual machine
 780     bytecode instructions which comprise the target program.  Typically, these alterations
 781     are to add "events" to the code of a method - for example, to add, at the beginning of a method,
 782     a call to <code>MyProfiler.methodEntered()</code>.
 783     Since the changes are purely additive, they do not modify application
 784     state or behavior.
 785     Because the inserted agent code is standard bytecodes, the VM can run at full speed,
 786     optimizing not only the target program but also the instrumentation.  If the
 787     instrumentation does not involve switching from bytecode execution, no expensive
 788     state transitions are needed.  The result is high performance events.
 789     This approach also provides complete control to the agent: instrumentation can be
 790     restricted to "interesting" portions of the code (e.g., the end user's code) and
 791     can be conditional.  Instrumentation can run entirely in Java programming language
 792     code or can call into the native agent.  Instrumentation can simply maintain
 793     counters or can statistically sample events.
 794     <p/>
 795     Instrumentation can be inserted in one of three ways:
 796     <ul>
 797       <li>
 798         Static Instrumentation: The class file is instrumented before it
 799         is loaded into the VM - for example, by creating a duplicate directory of
 800         <code>*.class</code> files which have been modified to add the instrumentation.
 801         This method is extremely awkward and, in general, an agent cannot know
 802         the origin of the class files which will be loaded.
 803       </li>
 804       <li>
 805         Load-Time Instrumentation: When a class file is loaded by the VM, the raw
 806         bytes of the class file are sent for instrumentation to the agent.
 807         The <eventlink id="ClassFileLoadHook"/>
 808         event, triggered by the class load,
 809         provides this functionality.  This mechanism provides efficient
 810         and complete access to one-time instrumentation.
 811       </li>
 812       <li>
 813         Dynamic Instrumentation: A class which is already loaded (and possibly
 814         even running) is modified.  This optional feature is provided by the
 815         <eventlink id="ClassFileLoadHook"/> event, triggered by calling the
 816         <functionlink id="RetransformClasses"/> function.
 817         Classes can be modified multiple times and can be returned to their
 818         original state.
 819         The mechanism allows instrumentation which changes during the
 820         course of execution.
 821       </li>
 822     </ul>
 823     <p/>
 824     The class modification functionality provided in this interface
 825     is intended to provide a mechanism for instrumentation
 826     (the <eventlink id="ClassFileLoadHook"/> event
 827     and the <functionlink id="RetransformClasses"/> function)
 828     and, during development, for fix-and-continue debugging
 829     (the <functionlink id="RedefineClasses"/> function).
 830     <p/>
 831     Care must be taken to avoid perturbing dependencies, especially when
 832     instrumenting core classes.  For example, an approach to getting notification
 833     of every object allocation is to instrument the constructor on
 834     <code>Object</code>.  Assuming that the constructor is initially
 835     empty, the constructor could be changed to:
 836     <example>
 837       public Object() {
 838         MyProfiler.allocationTracker(this);
 839       }
 840     </example>
 841     However, if this change was made using the
 842     <eventlink id="ClassFileLoadHook"/>
 843     event then this might impact a typical VM as follows:
 844     the first created object will call the constructor causing a class load of
 845     <code>MyProfiler</code>; which will then cause
 846     object creation, and since <code>MyProfiler</code> isn't loaded yet,
 847     infinite recursion; resulting in a stack overflow.  A refinement of this
 848     would be to delay invoking the tracking method until a safe time.  For
 849     example, <code>trackAllocations</code> could be set in the
 850     handler for the <code>VMInit</code> event.
 851     <example>
 852       static boolean trackAllocations = false;
 853 
 854       public Object() {
 855         if (trackAllocations) {
 856           MyProfiler.allocationTracker(this);
 857         }
 858       }
 859     </example>
 860     <p/>
 861     The <functionlink id="SetNativeMethodPrefix"/> allows native methods
 862     to be instrumented by the use of wrapper methods.
 863   </intro>
 864 
 865 <intro id="bcimodules" label="Bytecode Instrumentation of code in modules">
 866   Agents can use the functions <functionlink id="AddModuleReads"/>,
 867   <functionlink id="AddModuleExports"/>, <functionlink id="AddModuleOpens"/>,
 868   <functionlink id="AddModuleUses"/> and <functionlink id="AddModuleProvides"/>
 869   to update a module to expand the set of modules that it reads, the set of
 870   packages that it exports or opens to other modules, or the services that it
 871   uses and provides.
 872   <p/>
 873   As an aid to agents that deploy supporting classes on the search path of
 874   the bootstrap class loader, or the search path of the class loader that
 875   loads the main class, the Java virtual machine arranges for the module
 876   of classes transformed by the <eventlink id="ClassFileLoadHook"/> event to
 877   read the unnamed module of both class loaders.
 878 </intro>
 879 
 880   <intro id="mUTF" label="Modified UTF-8 String Encoding">
 881     <jvmti/> uses modified UTF-8 to encode character strings.
 882     This is the same encoding used by JNI.
 883     Modified UTF-8 differs
 884     from standard UTF-8 in the representation of supplementary characters
 885     and of the null character. See the
 886     <externallink id="jni/types.html#modified-utf-8-strings">
 887       Modified UTF-8 Strings</externallink>
 888     section of the JNI specification for details.
 889   </intro>
 890 
 891   <intro id="context" label="Specification Context">
 892     Since this interface provides access to the state of applications running in the
 893     Java virtual machine;
 894     terminology refers to the Java platform and not the native
 895     platform (unless stated otherwise).  For example:
 896     <ul>
 897       <li>"thread" means Java programming language thread.</li>
 898       <li>"stack frame" means Java virtual machine stack frame.</li>
 899       <li>"class" means Java programming language class.</li>
 900       <li>"heap" means Java virtual machine heap.</li>
 901       <li>"monitor" means Java programming language object monitor.</li>
 902     </ul>
 903     <p/>
 904     Sun, Sun Microsystems, the Sun logo, Java, and JVM
 905     are trademarks or registered trademarks of Oracle
 906     and/or its affiliates, in the U.S. and other countries.
 907   </intro>
 908 
 909 
 910 <functionsection label="Functions">
 911   <intro id="jvmtiEnvAccess" label="Accessing Functions">
 912     Native code accesses <jvmti/> features
 913     by calling <jvmti/> functions.
 914     Access to <jvmti/> functions is by use of an interface pointer
 915     in the same manner as
 916     <externallink id="jni/design.html">Java
 917       Native Interface (JNI) functions</externallink> are accessed.
 918     The <jvmti/> interface pointer is called the
 919     <i>environment pointer</i>.
 920     <p/>
 921     An environment pointer is a pointer to an environment and has
 922     the type <code>jvmtiEnv*</code>.
 923     An environment has information about its <jvmti/> connection.
 924     The first value in the environment is a pointer to the function table.
 925     The function table is an array of pointers to <jvmti/> functions.
 926     Every function pointer is at a predefined offset inside the
 927     array.
 928     <p/>
 929     When used from the C language:
 930     double indirection is used to access the functions;
 931     the environment pointer provides context and is the first
 932     parameter of each function call; for example:
 933     <example>
 934 jvmtiEnv *jvmti;
 935 ...
 936 jvmtiError err = (*jvmti)->GetLoadedClasses(jvmti, &amp;class_count, &amp;classes);
 937     </example>
 938     <p/>
 939     When used from the C++ language:
 940     functions are accessed as member functions of <code>jvmtiEnv</code>;
 941     the environment pointer is not passed to the function call; for example:
 942     <example>
 943 jvmtiEnv *jvmti;
 944 ...
 945 jvmtiError err = jvmti->GetLoadedClasses(&amp;class_count, &amp;classes);
 946     </example>
 947     Unless otherwise stated, all examples and declarations in this
 948     specification use the C language.
 949     <p/>
 950     A <jvmti/> environment can be obtained through the JNI Invocation API
 951     <code>GetEnv</code> function:
 952     <example>
 953 jvmtiEnv *jvmti;
 954 ...
 955 (*jvm)->GetEnv(jvm, &amp;jvmti, JVMTI_VERSION_1_0);
 956     </example>
 957     Each call to <code>GetEnv</code>
 958     creates a new <jvmti/> connection and thus
 959     a new <jvmti/> environment.
 960     The <code>version</code> argument of <code>GetEnv</code> must be
 961     a <jvmti/> version.
 962     The returned environment may have a different version than the
 963     requested version but the returned environment must be compatible.
 964     <code>GetEnv</code> will return <code>JNI_EVERSION</code> if a
 965     compatible version is not available, if <jvmti/> is not supported or
 966     <jvmti/> is not supported in the current VM configuration.
 967     Other interfaces may be added for creating <jvmti/> environments
 968     in specific contexts.
 969     Each environment has its own state (for example,
 970     <functionlink id="SetEventNotificationMode">desired events</functionlink>,
 971     <functionlink id="SetEventCallbacks">event handling functions</functionlink>, and
 972     <functionlink id="AddCapabilities">capabilities</functionlink>).
 973     An environment is released with
 974     <functionlink id="DisposeEnvironment"></functionlink>.
 975     Thus, unlike JNI which has one environment per thread, <jvmti/> environments work
 976     across threads and are created dynamically.
 977   </intro>
 978 
 979   <intro id="functionReturn" label="Function Return Values">
 980     <jvmti/> functions always return an
 981     <internallink id="ErrorSection">error code</internallink> via the
 982     <datalink id="jvmtiError"/> function return value.
 983     Some functions can return additional
 984     values through pointers provided by the calling function.
 985     In some cases, <jvmti/> functions allocate memory that your program must
 986     explicitly deallocate. This is indicated in the individual <jvmti/>
 987     function descriptions.  Empty lists, arrays, sequences, etc are
 988     returned as <code>NULL</code>.
 989     <p/>
 990     In the event that the <jvmti/> function encounters
 991     an error (any return value other than <code>JVMTI_ERROR_NONE</code>) the values
 992     of memory referenced by argument pointers is undefined, but no memory
 993     will have been allocated and no global references will have been allocated.
 994     If the error occurs because of invalid input, no action will have occurred.
 995   </intro>
 996 
 997 <intro id="refs" label="Managing JNI Object References">
 998     <jvmti/> functions identify objects with JNI references
 999     (<datalink id="jobject"/> and <datalink id="jclass"/>)
1000     and their derivatives
1001     (<datalink id="jthread"/> and <datalink id="jthreadGroup"/>).
1002     References passed to
1003     <jvmti/> functions can be either global or local, but they must be
1004     strong references. All references returned by <jvmti/> functions are
1005     local references--these local references are created
1006     during the <jvmti/> call.
1007     Local references are a resource that must be managed (see the
1008     <externallink id="jni/functions.html#local-references">
1009       JNI Documentation</externallink>).
1010     When threads return from native code all local references
1011     are freed.  Note that some threads, including typical
1012     agent threads, will never return from native code.
1013     A thread is ensured the ability to create sixteen local
1014     references without the need for any explicit management.
1015     For threads executing a limited number of <jvmti/> calls before
1016     returning from native code
1017     (for example, threads processing events),
1018     it may be determined that no explicit management
1019     is needed.
1020     However, long running agent threads will need explicit
1021     local reference management--usually with the JNI functions
1022     <code>PushLocalFrame</code> and <code>PopLocalFrame</code>.
1023     Conversely, to preserve references beyond the
1024     return from native code, they must be converted to global references.
1025     These rules do not apply to <datalink id="jmethodID"/> and <datalink id="jfieldID"/>
1026     as they are not <datalink id="jobject"/>s.
1027 </intro>
1028 
1029     <intro id="prereqState" label="Prerequisite State for Calling Functions">
1030       Unless the function explicitly states that the agent must bring
1031       a thread or the VM to a particular state (for example, suspended),
1032       the <jvmti/> implementation is responsible for bringing the VM to a
1033       safe and consistent state for performing the function.
1034     </intro>
1035 
1036     <intro id="functionsExceptions" label="Exceptions and Functions">
1037       <jvmti/> functions never throw exceptions; error conditions are
1038       communicated via the
1039       <internallink id="functionReturn">function return value</internallink>.
1040       Any existing exception state is preserved across a call to a
1041       <jvmti/> function.
1042       See the
1043       <externallink
1044         id="jni/design.html#java-exceptions"
1045              >Java Exceptions</externallink>
1046       section of the JNI specification for information on handling exceptions.
1047     </intro>
1048 
1049   <category id="memory" label="Memory Management">
1050     <intro>
1051       These functions provide for the allocation and deallocation of
1052       memory used by <jvmti/> functionality and can be used to provide
1053       working memory for agents.
1054       Memory managed by <jvmti/> is not compatible with other memory
1055       allocation libraries and mechanisms.
1056     </intro>
1057 
1058     <function id="Allocate" jkernel="yes" phase="any" callbacksafe="safe" impl="notrace" num="46">
1059       <synopsis>Allocate</synopsis>
1060       <description>
1061         Allocate an area of memory through the <jvmti/> allocator.
1062         The allocated
1063         memory should be freed with <functionlink id="Deallocate"></functionlink>.
1064       </description>
1065       <origin>jvmdi</origin>
1066       <capabilities>
1067       </capabilities>
1068       <parameters>
1069         <param id="size">
1070           <jlong/>
1071           <description>
1072             The number of bytes to allocate.
1073             <rationale>
1074               <code>jlong</code> is used for compatibility with JVMDI.
1075             </rationale>
1076           </description>
1077         </param>
1078         <param id="mem_ptr">
1079           <allocbuf incount="size"><uchar/></allocbuf>
1080           <description>
1081             On return, a pointer to the beginning of the allocated memory.
1082             If <code>size</code> is zero, <code>NULL</code> is returned.
1083           </description>
1084         </param>
1085       </parameters>
1086       <errors>
1087         <error id="JVMTI_ERROR_OUT_OF_MEMORY">
1088           Memory request cannot be honored.
1089         </error>
1090         <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
1091           <paramlink id="size"></paramlink> is less than zero.
1092         </error>
1093       </errors>
1094     </function>
1095 
1096     <function id="Deallocate" jkernel="yes" phase="any" callbacksafe="safe" impl="notrace" num="47">
1097       <synopsis>Deallocate</synopsis>
1098       <description>
1099         Deallocate <code>mem</code>  using the <jvmti/> allocator.
1100         This function should
1101         be used to deallocate any memory allocated and returned
1102         by a <jvmti/> function
1103         (including memory allocated with <functionlink id="Allocate"></functionlink>).
1104         All allocated memory must be deallocated
1105         or the memory cannot be reclaimed.
1106       </description>
1107       <origin>jvmdi</origin>
1108       <capabilities>
1109       </capabilities>
1110       <parameters>
1111         <param id="mem">
1112           <outbuf>
1113             <uchar/>
1114             <nullok>the call is ignored</nullok>
1115           </outbuf>
1116           <description>
1117             A pointer to the beginning of the allocated memory.
1118             Please ignore "On return, the elements are set."
1119               <todo>keep it from generating "On return, the elements are set"</todo>
1120           </description>
1121         </param>
1122       </parameters>
1123       <errors>
1124       </errors>
1125     </function>
1126   </category>
1127 
1128   <category id="threadCategory" label="Thread">
1129     <intro>
1130     </intro>
1131 
1132     <function id="GetThreadState" num="17">
1133       <synopsis>Get Thread State</synopsis>
1134       <description>
1135         Get the state of a thread.  The state of the thread is represented by the
1136         answers to the hierarchical set of questions below:
1137           <ul type="circle">
1138             <li><i>Alive?</i>
1139               <ul>
1140                 <li>Not alive.
1141                   <ul type="circle">
1142                     <li><i>Why not alive?</i>
1143                       <ul>
1144                         <li>New.</li>
1145                         <li>Terminated (<datalink
1146                             id="JVMTI_THREAD_STATE_TERMINATED"><code>JVMTI_THREAD_STATE_TERMINATED</code></datalink>)</li>
1147                       </ul>
1148                     </li>
1149                   </ul>
1150                 </li>
1151                 <li>Alive (<datalink
1152                     id="JVMTI_THREAD_STATE_ALIVE"><code>JVMTI_THREAD_STATE_ALIVE</code></datalink>)
1153                   <ul type="circle">
1154                     <li><i>Suspended?</i>
1155                       <ul>
1156                         <li>Suspended (<datalink
1157                             id="JVMTI_THREAD_STATE_SUSPENDED"><code>JVMTI_THREAD_STATE_SUSPENDED</code></datalink>)</li>
1158                         <li>Not suspended</li>
1159                       </ul>
1160                     </li>
1161                     <li><i>Interrupted?</i>
1162                       <ul>
1163                         <li>Interrupted (<datalink
1164                             id="JVMTI_THREAD_STATE_INTERRUPTED"><code>JVMTI_THREAD_STATE_INTERRUPTED</code></datalink>)</li>
1165                         <li>Not interrupted.</li>
1166                       </ul>
1167                     </li>
1168                     <li><i>In native?</i>
1169                       <ul>
1170                         <li>In native code (<datalink
1171                             id="JVMTI_THREAD_STATE_IN_NATIVE"><code>JVMTI_THREAD_STATE_IN_NATIVE</code></datalink>)</li>
1172                         <li>In Java programming language code</li>
1173                       </ul>
1174                     </li>
1175                     <li><i>What alive state?</i>
1176                       <ul>
1177                         <li>Runnable (<datalink
1178                             id="JVMTI_THREAD_STATE_RUNNABLE"><code>JVMTI_THREAD_STATE_RUNNABLE</code></datalink>)</li>
1179                         <li>Blocked (<datalink
1180                             id="JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER"><code>JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER</code></datalink>)</li>
1181                         <li>Waiting (<datalink
1182                             id="JVMTI_THREAD_STATE_WAITING"><code>JVMTI_THREAD_STATE_WAITING</code></datalink>)
1183                           <ul type="circle">
1184                             <li><i>Timed wait?</i>
1185                               <ul>
1186                                 <li>Indefinite (<datalink
1187                                     id="JVMTI_THREAD_STATE_WAITING_INDEFINITELY"><code>JVMTI_THREAD_STATE_WAITING_INDEFINITELY</code></datalink></li>
1188                                 <li>Timed (<datalink
1189                                     id="JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT"><code>JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT</code></datalink>)</li>
1190                               </ul>
1191                             </li>
1192                             <li><i>Why waiting?</i>
1193                               <ul>
1194                                 <li>Object.wait (<datalink
1195                                     id="JVMTI_THREAD_STATE_IN_OBJECT_WAIT"><code>JVMTI_THREAD_STATE_IN_OBJECT_WAIT</code></datalink>)</li>
1196                                 <li>LockSupport.park (<datalink
1197                                     id="JVMTI_THREAD_STATE_PARKED"><code>JVMTI_THREAD_STATE_PARKED</code></datalink>)</li>
1198                                 <li>Sleeping (<datalink
1199                                     id="JVMTI_THREAD_STATE_SLEEPING"><code>JVMTI_THREAD_STATE_SLEEPING</code></datalink>)</li>
1200                               </ul>
1201                             </li>
1202                           </ul>
1203                         </li>
1204                       </ul>
1205                     </li>
1206                   </ul>
1207                 </li>
1208               </ul>
1209             </li>
1210           </ul>
1211         <p/>
1212         The answers are represented by the following bit vector.
1213         <constants id="jvmtiThreadState" label="Thread State Flags" kind="bits">
1214           <constant id="JVMTI_THREAD_STATE_ALIVE" num="0x0001">
1215             Thread is alive. Zero if thread is new (not started) or terminated.
1216           </constant>
1217           <constant id="JVMTI_THREAD_STATE_TERMINATED" num="0x0002">
1218             Thread has completed execution.
1219           </constant>
1220           <constant id="JVMTI_THREAD_STATE_RUNNABLE" num="0x0004">
1221             Thread is runnable.
1222           </constant>
1223           <constant id="JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER" num="0x0400">
1224             Thread is waiting to enter a synchronization block/method or,
1225             after an <code>Object.wait()</code>, waiting to re-enter a
1226             synchronization block/method.
1227           </constant>
1228           <constant id="JVMTI_THREAD_STATE_WAITING" num="0x0080">
1229             Thread is waiting.
1230           </constant>
1231           <constant id="JVMTI_THREAD_STATE_WAITING_INDEFINITELY" num="0x0010">
1232             Thread is waiting without a timeout.
1233             For example, <code>Object.wait()</code>.
1234           </constant>
1235           <constant id="JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT" num="0x0020">
1236             Thread is waiting with a maximum time to wait specified.
1237             For example, <code>Object.wait(long)</code>.
1238           </constant>
1239           <constant id="JVMTI_THREAD_STATE_SLEEPING" num="0x0040">
1240             Thread is sleeping -- <code>Thread.sleep(long)</code>.
1241           </constant>
1242           <constant id="JVMTI_THREAD_STATE_IN_OBJECT_WAIT" num="0x0100">
1243             Thread is waiting on an object monitor -- <code>Object.wait</code>.
1244           </constant>
1245           <constant id="JVMTI_THREAD_STATE_PARKED" num="0x0200">
1246             Thread is parked, for example: <code>LockSupport.park</code>,
1247             <code>LockSupport.parkUtil</code> and <code>LockSupport.parkNanos</code>.
1248           </constant>
1249           <constant id="JVMTI_THREAD_STATE_SUSPENDED" num="0x100000">
1250             Thread suspended.
1251             <code>java.lang.Thread.suspend()</code>
1252             or a <jvmti/> suspend function
1253             (such as <functionlink id="SuspendThread"></functionlink>)
1254             has been called on the thread. If this bit
1255             is set, the other bits refer to the thread state before suspension.
1256           </constant>
1257           <constant id="JVMTI_THREAD_STATE_INTERRUPTED" num="0x200000">
1258             Thread has been interrupted.
1259           </constant>
1260           <constant id="JVMTI_THREAD_STATE_IN_NATIVE" num="0x400000">
1261             Thread is in native code--that is, a native method is running
1262             which has not called back into the VM or Java programming
1263             language code.
1264             <p/>
1265             This flag is not set when running VM compiled Java programming
1266             language code nor is it set when running VM code or
1267             VM support code. Native VM interface functions, such as JNI and
1268             <jvmti/> functions, may be implemented as VM code.
1269           </constant>
1270           <constant id="JVMTI_THREAD_STATE_VENDOR_1" num="0x10000000">
1271             Defined by VM vendor.
1272           </constant>
1273           <constant id="JVMTI_THREAD_STATE_VENDOR_2" num="0x20000000">
1274             Defined by VM vendor.
1275           </constant>
1276           <constant id="JVMTI_THREAD_STATE_VENDOR_3" num="0x40000000">
1277             Defined by VM vendor.
1278           </constant>
1279         </constants>
1280         The following definitions are used to convert <jvmti/> thread state
1281         to <code>java.lang.Thread.State</code> style states.
1282         <constants id="jvmtiJavaLangThreadState" label="java.lang.Thread.State Conversion Masks" kind="bits">
1283           <constant id="JVMTI_JAVA_LANG_THREAD_STATE_MASK"
1284                      num="JVMTI_THREAD_STATE_TERMINATED | JVMTI_THREAD_STATE_ALIVE | JVMTI_THREAD_STATE_RUNNABLE | JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER | JVMTI_THREAD_STATE_WAITING | JVMTI_THREAD_STATE_WAITING_INDEFINITELY | JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT">
1285             Mask the state with this before comparison
1286           </constant>
1287           <constant id="JVMTI_JAVA_LANG_THREAD_STATE_NEW"
1288                      num="0">
1289             <code>java.lang.Thread.State.NEW</code>
1290           </constant>
1291           <constant id="JVMTI_JAVA_LANG_THREAD_STATE_TERMINATED"
1292                      num="JVMTI_THREAD_STATE_TERMINATED">
1293             <code>java.lang.Thread.State.TERMINATED</code>
1294           </constant>
1295           <constant id="JVMTI_JAVA_LANG_THREAD_STATE_RUNNABLE"
1296                      num="JVMTI_THREAD_STATE_ALIVE | JVMTI_THREAD_STATE_RUNNABLE">
1297             <code>java.lang.Thread.State.RUNNABLE</code>
1298           </constant>
1299           <constant id="JVMTI_JAVA_LANG_THREAD_STATE_BLOCKED"
1300                      num="JVMTI_THREAD_STATE_ALIVE | JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER">
1301             <code>java.lang.Thread.State.BLOCKED</code>
1302           </constant>
1303           <constant id="JVMTI_JAVA_LANG_THREAD_STATE_WAITING"
1304                      num="JVMTI_THREAD_STATE_ALIVE | JVMTI_THREAD_STATE_WAITING | JVMTI_THREAD_STATE_WAITING_INDEFINITELY">
1305             <code>java.lang.Thread.State.WAITING</code>
1306           </constant>
1307           <constant id="JVMTI_JAVA_LANG_THREAD_STATE_TIMED_WAITING"
1308                      num="JVMTI_THREAD_STATE_ALIVE | JVMTI_THREAD_STATE_WAITING | JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT">
1309             <code>java.lang.Thread.State.TIMED_WAITING</code>
1310           </constant>
1311         </constants>
1312         <b>Rules</b>
1313         <p/>
1314         There can be no more than one answer to a question, although there can be no
1315         answer (because the answer is unknown, does not apply, or none of the answers is
1316         correct).  An answer is set only when the enclosing answers match.
1317         That is, no more than one of
1318           <ul type="circle">
1319               <li><code>JVMTI_THREAD_STATE_RUNNABLE</code></li>
1320               <li><code>JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER</code></li>
1321               <li><code>JVMTI_THREAD_STATE_WAITING</code></li>
1322           </ul>
1323         can be set (a <tm>J2SE</tm> compliant implementation will always set
1324         one of these if <code>JVMTI_THREAD_STATE_ALIVE</code> is set).
1325         And if any of these are set, the enclosing answer
1326         <code>JVMTI_THREAD_STATE_ALIVE</code> is set.
1327         No more than one of
1328           <ul type="circle">
1329               <li><code>JVMTI_THREAD_STATE_WAITING_INDEFINITELY</code></li>
1330               <li><code>JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT</code></li>
1331           </ul>
1332         can be set (a <tm>J2SE</tm> compliant implementation will always set
1333         one of these if <code>JVMTI_THREAD_STATE_WAITING</code> is set).
1334         And if either is set, the enclosing answers
1335         <code>JVMTI_THREAD_STATE_ALIVE</code> and
1336         <code>JVMTI_THREAD_STATE_WAITING</code> are set.
1337         No more than one of
1338           <ul type="circle">
1339               <li><code>JVMTI_THREAD_STATE_IN_OBJECT_WAIT</code></li>
1340               <li><code>JVMTI_THREAD_STATE_PARKED</code></li>
1341               <li><code>JVMTI_THREAD_STATE_SLEEPING</code></li>
1342           </ul>
1343         can be set. And if any of these is set, the enclosing answers
1344         <code>JVMTI_THREAD_STATE_ALIVE</code> and
1345         <code>JVMTI_THREAD_STATE_WAITING</code> are set.
1346         Also, if <code>JVMTI_THREAD_STATE_SLEEPING</code> is set,
1347         then <code>JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT</code> is set.
1348         If a state <i>A</i> is implemented using the mechanism of
1349         state <i>B</i> then it is state <i>A</i> which
1350         is returned by this function.
1351         For example, if <code>Thread.sleep(long)</code>
1352         is implemented using <code>Object.wait(long)</code>
1353         then it is still <code>JVMTI_THREAD_STATE_SLEEPING</code>
1354         which is returned.
1355         More than one of
1356           <ul type="circle">
1357               <li><code>JVMTI_THREAD_STATE_SUSPENDED</code></li>
1358               <li><code>JVMTI_THREAD_STATE_INTERRUPTED</code></li>
1359               <li><code>JVMTI_THREAD_STATE_IN_NATIVE</code></li>
1360           </ul>
1361         can be set, but if any is set,
1362         <code>JVMTI_THREAD_STATE_ALIVE</code> is set.
1363         <p/>
1364         And finally,
1365         <code>JVMTI_THREAD_STATE_TERMINATED</code> cannot be set unless
1366         <code>JVMTI_THREAD_STATE_ALIVE</code> is not set.
1367         <p/>
1368         The thread state representation is designed for extension in future versions
1369         of the specification; thread state values should be used accordingly, that is
1370         they should not be used as ordinals.
1371         Most queries can be made by testing a single bit, if use in a switch statement is desired,
1372         the state bits should be masked with the interesting bits.
1373         All bits not defined above are reserved for future use.
1374         A VM, compliant to the current specification, must set reserved bits to zero.
1375         An agent should ignore reserved bits --
1376         they should not be assumed to be zero and thus should not be included in comparisons.
1377         <p/>
1378         <b>Examples</b>
1379         <p/>
1380         Note that the values below exclude reserved and vendor bits.
1381         <p/>
1382         The state of a thread blocked at a <code>synchronized</code>-statement would be:
1383         <example>
1384             JVMTI_THREAD_STATE_ALIVE + JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER
1385         </example>
1386         The state of a thread which hasn't started yet would be:
1387         <example>
1388             0
1389         </example>
1390         The state of a thread at a <code>Object.wait(3000)</code> would be:
1391         <example>
1392             JVMTI_THREAD_STATE_ALIVE + JVMTI_THREAD_STATE_WAITING +
1393                 JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT +
1394                 JVMTI_THREAD_STATE_MONITOR_WAITING
1395         </example>
1396         The state of a thread suspended while runnable would be:
1397         <example>
1398             JVMTI_THREAD_STATE_ALIVE + JVMTI_THREAD_STATE_RUNNABLE + JVMTI_THREAD_STATE_SUSPENDED
1399         </example>
1400         <p/>
1401         <b>Testing the State</b>
1402         <p/>
1403         In most cases, the thread state can be determined by testing the one bit corresponding
1404         to that question.  For example, the code to test if a thread is sleeping:
1405         <example>
1406         jint state;
1407         jvmtiError err;
1408 
1409         err = (*jvmti)-&gt;GetThreadState(jvmti, thread, &amp;state);
1410         if (err == JVMTI_ERROR_NONE) {
1411            if (state &amp; JVMTI_THREAD_STATE_SLEEPING) {  ...
1412         </example>
1413         <p/>
1414         For waiting (that is, in <code>Object.wait</code>, parked, or sleeping) it would be:
1415         <example>
1416            if (state &amp; JVMTI_THREAD_STATE_WAITING) {  ...
1417         </example>
1418         For some states, more than one bit will need to be tested as is the case
1419         when testing if a thread has not yet been started:
1420         <example>
1421            if ((state &amp; (JVMTI_THREAD_STATE_ALIVE | JVMTI_THREAD_STATE_TERMINATED)) == 0)  {  ...
1422         </example>
1423         To distinguish timed from untimed <code>Object.wait</code>:
1424         <example>
1425            if (state &amp; JVMTI_THREAD_STATE_IN_OBJECT_WAIT)  {
1426              if (state &amp; JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT)  {
1427                printf("in Object.wait(long timeout)\n");
1428              } else {
1429                printf("in Object.wait()\n");
1430              }
1431            }
1432         </example>
1433         <p/>
1434         <b>Relationship to <code>java.lang.Thread.State</code></b>
1435         <p/>
1436         The thread state represented by <code>java.lang.Thread.State</code>
1437         returned from <code>java.lang.Thread.getState()</code> is a subset of the
1438         information returned from this function.
1439         The corresponding <code>java.lang.Thread.State</code> can be determined
1440         by using the provided conversion masks.
1441         For example, this returns the name of the <code>java.lang.Thread.State</code> thread state:
1442         <example>
1443             err = (*jvmti)-&gt;GetThreadState(jvmti, thread, &amp;state);
1444             abortOnError(err);
1445             switch (state &amp; JVMTI_JAVA_LANG_THREAD_STATE_MASK) {
1446             case JVMTI_JAVA_LANG_THREAD_STATE_NEW:
1447               return "NEW";
1448             case JVMTI_JAVA_LANG_THREAD_STATE_TERMINATED:
1449               return "TERMINATED";
1450             case JVMTI_JAVA_LANG_THREAD_STATE_RUNNABLE:
1451               return "RUNNABLE";
1452             case JVMTI_JAVA_LANG_THREAD_STATE_BLOCKED:
1453               return "BLOCKED";
1454             case JVMTI_JAVA_LANG_THREAD_STATE_WAITING:
1455               return "WAITING";
1456             case JVMTI_JAVA_LANG_THREAD_STATE_TIMED_WAITING:
1457               return "TIMED_WAITING";
1458             }
1459         </example>
1460       </description>
1461       <origin>new</origin>
1462       <capabilities>
1463       </capabilities>
1464       <parameters>
1465         <param id="thread">
1466           <jthread null="current" started="maybe" impl="noconvert"/>
1467             <description>
1468               The thread to query.
1469             </description>
1470         </param>
1471         <param id="thread_state_ptr">
1472           <outptr><jint/></outptr>
1473           <description>
1474             On return, points to state flags,
1475             as defined by the <internallink id="jvmtiThreadState">Thread State Flags</internallink>.
1476           </description>
1477         </param>
1478       </parameters>
1479       <errors>
1480       </errors>
1481     </function>
1482 
1483     <function id="GetCurrentThread" phase="start" num="18" since="1.1">
1484       <synopsis>Get Current Thread</synopsis>
1485       <description>
1486         Get the current thread.
1487         The current thread is the Java programming language thread which has called the function.
1488         The function may return <code>NULL</code> in the start phase if the
1489         <internallink id="jvmtiCapabilities.can_generate_early_vmstart">
1490         <code>can_generate_early_vmstart</code></internallink> capability is enabled
1491         and the <code>java.lang.Thread</code> class has not been initialized yet.
1492         <p/>
1493         Note that most <jvmti/> functions that take a thread
1494         as an argument will accept <code>NULL</code> to mean
1495         the current thread.
1496       </description>
1497       <origin>new</origin>
1498       <capabilities>
1499       </capabilities>
1500       <parameters>
1501         <param id="thread_ptr">
1502           <outptr><jthread/></outptr>
1503           <description>
1504              On return, points to the current thread, or <code>NULL</code>.
1505           </description>
1506         </param>
1507       </parameters>
1508       <errors>
1509       </errors>
1510     </function>
1511 
1512     <function id="GetAllThreads" num="4">
1513       <synopsis>Get All Threads</synopsis>
1514       <description>
1515         Get all live threads.
1516         The threads are Java programming language threads;
1517         that is, threads that are attached to the VM.
1518         A thread is live if <code>java.lang.Thread.isAlive()</code>
1519         would return <code>true</code>, that is, the thread has
1520         been started and has not yet died.
1521         The universe of threads is determined by the context of the <jvmti/>
1522         environment, which typically is all threads attached to the VM.
1523         Note that this includes <jvmti/> agent threads
1524         (see <functionlink id="RunAgentThread"/>).
1525       </description>
1526       <origin>jvmdi</origin>
1527       <capabilities>
1528       </capabilities>
1529       <parameters>
1530         <param id="threads_count_ptr">
1531           <outptr><jint/></outptr>
1532           <description>
1533             On return, points to the number of running threads.
1534           </description>
1535         </param>
1536         <param id="threads_ptr">
1537           <allocbuf outcount="threads_count_ptr"><jthread/></allocbuf>
1538             <description>
1539               On return, points to an array of references, one
1540               for each running thread.
1541             </description>
1542         </param>
1543       </parameters>
1544       <errors>
1545       </errors>
1546     </function>
1547 
1548     <function id="SuspendThread" num="5">
1549       <synopsis>Suspend Thread</synopsis>
1550       <description>
1551         Suspend the specified thread. If the calling thread is specified,
1552         this function will not return until some other thread calls
1553         <functionlink id="ResumeThread"></functionlink>.
1554         If the thread is currently suspended, this function
1555         does nothing and returns an error.
1556       </description>
1557       <origin>jvmdi</origin>
1558       <capabilities>
1559         <required id="can_suspend"></required>
1560       </capabilities>
1561       <parameters>
1562         <param id="thread">
1563           <jthread null="current"/>
1564             <description>
1565               The thread to suspend.
1566             </description>
1567         </param>
1568       </parameters>
1569       <errors>
1570         <error id="JVMTI_ERROR_THREAD_SUSPENDED">
1571           Thread already suspended.
1572         </error>
1573       </errors>
1574     </function>
1575 
1576     <elide>
1577     <function id="SuspendAllThreads" num="101">
1578       <synopsis>Suspend All Threads</synopsis>
1579       <description>
1580         <issue>
1581             There has been no explicit call for this function, and it will
1582             thus be removed if there is no interest.
1583         </issue>
1584         Suspend all live threads except:
1585         <ul>
1586           <li>already suspended threads</li>
1587           <li>those listed in <paramlink id="except_list"></paramlink></li>
1588           <li>certain system (non application) threads, as determined
1589             by the VM implementation</li>
1590         </ul>
1591         The threads are Java programming language threads;
1592         native threads which are not attached to the VM are not
1593         Java programming language threads.
1594         A thread is live if <code>java.lang.Thread.isAlive()</code>
1595         would return <code>true</code>, that is, the thread has
1596         been started and has not yet died.
1597         The universe of threads is determined
1598         by the context of the <jvmti/>
1599         environment, which, typically, is all threads attached to the VM,
1600         except critical VM internal threads and <jvmti/> agent threads
1601         (see <functionlink id="RunAgentThread"/>).
1602         <p/>
1603         If the calling thread is specified,
1604         all other threads are suspended first then the caller thread is suspended -
1605         this function will not return until some other thread calls
1606         <functionlink id="ResumeThread"></functionlink>.
1607         <p/>
1608         The list of actually
1609         suspended threads is returned in
1610         <paramlink id="suspended_list_ptr"></paramlink>.
1611         Suspension is as defined in <functionlink id="SuspendThread"></functionlink>.
1612         <functionlink id="ResumeThreadList"></functionlink>
1613         can be used to resume the suspended threads.
1614       </description>
1615       <origin>new</origin>
1616       <capabilities>
1617         <required id="can_suspend"></required>
1618       </capabilities>
1619       <parameters>
1620         <param id="except_count">
1621           <jint min="0"/>
1622           <description>
1623             The number of threads in the list of threads not to be suspended.
1624           </description>
1625         </param>
1626         <param id="except_list">
1627             <inbuf incount="except_count">
1628               <jthread/>
1629               <nullok>not an error if <code>except_count == 0</code></nullok>
1630             </inbuf>
1631             <description>
1632               The list of threads not to be suspended.
1633             </description>
1634         </param>
1635         <param id="suspended_count_ptr">
1636           <outptr><jint/></outptr>
1637           <description>
1638             On return, points to the number of threads suspended by this call.
1639           </description>
1640         </param>
1641         <param id="suspended_list_ptr">
1642           <allocbuf outcount="suspended_count_ptr"><jthread/></allocbuf>
1643             <description>
1644               On return, points to an array of references, one
1645               for each thread suspended.
1646             </description>
1647         </param>
1648       </parameters>
1649       <errors>
1650         <error id="JVMTI_ERROR_INVALID_THREAD">
1651           A thread in <paramlink id="except_list"></paramlink> was invalid.
1652         </error>
1653         <error id="JVMTI_ERROR_NULL_POINTER">
1654           Both <paramlink id="except_list"></paramlink> was <code>NULL</code>
1655           and <paramlink id="except_count"></paramlink> was non-zero.
1656         </error>
1657       </errors>
1658     </function>
1659     </elide>
1660 
1661     <function id="SuspendThreadList" num="92">
1662       <synopsis>Suspend Thread List</synopsis>
1663       <description>
1664         Suspend the <paramlink id="request_count"></paramlink>
1665         threads specified in the
1666         <paramlink id="request_list"></paramlink> array.
1667         Threads may be resumed with
1668         <functionlink id="ResumeThreadList"></functionlink> or
1669         <functionlink id="ResumeThread"></functionlink>.
1670         If the calling thread is specified in the
1671         <paramlink id="request_list"></paramlink> array, this function will
1672         not return until some other thread resumes it.
1673         Errors encountered in the suspension of a thread
1674         are returned in the <paramlink id="results"></paramlink>
1675         array, <b>not</b> in the return value of this function.
1676         Threads that are currently suspended do not change state.
1677       </description>
1678       <origin>jvmdi</origin>
1679       <capabilities>
1680         <required id="can_suspend"></required>
1681       </capabilities>
1682       <parameters>
1683         <param id="request_count">
1684           <jint min="0"/>
1685           <description>
1686             The number of threads to suspend.
1687           </description>
1688         </param>
1689         <param id="request_list">
1690           <inbuf incount="request_count"><jthread/></inbuf>
1691             <description>
1692               The list of threads to suspend.
1693             </description>
1694         </param>
1695         <param id="results">
1696           <outbuf incount="request_count"><enum>jvmtiError</enum></outbuf>
1697           <description>
1698             An agent supplied array of
1699             <paramlink id="request_count"></paramlink> elements.
1700             On return, filled with the error code for
1701             the suspend of the corresponding thread.
1702             The error code will be
1703             <errorlink id="JVMTI_ERROR_NONE"></errorlink>
1704             if the thread was suspended by this call.
1705             Possible error codes are those specified
1706             for <functionlink id="SuspendThread"></functionlink>.
1707           </description>
1708         </param>
1709       </parameters>
1710       <errors>
1711       </errors>
1712     </function>
1713 
1714     <function id="ResumeThread" num="6">
1715       <synopsis>Resume Thread</synopsis>
1716       <description>
1717         Resume a suspended thread.
1718         Any threads currently suspended through
1719         a <jvmti/> suspend function (eg.
1720         <functionlink id="SuspendThread"></functionlink>)
1721         or <code>java.lang.Thread.suspend()</code>
1722         will resume execution;
1723         all other threads are unaffected.
1724       </description>
1725       <origin>jvmdi</origin>
1726       <capabilities>
1727         <required id="can_suspend"></required>
1728       </capabilities>
1729       <parameters>
1730         <param id="thread">
1731           <jthread/>
1732             <description>
1733               The thread to resume.
1734             </description>
1735         </param>
1736       </parameters>
1737       <errors>
1738         <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
1739           Thread was not suspended.
1740         </error>
1741         <error id="JVMTI_ERROR_INVALID_TYPESTATE">
1742           The state of the thread has been modified, and is now inconsistent.
1743         </error>
1744       </errors>
1745     </function>
1746 
1747     <function id="ResumeThreadList" num="93">
1748       <synopsis>Resume Thread List</synopsis>
1749       <description>
1750         Resume the <paramlink id="request_count"></paramlink>
1751         threads specified in the
1752         <paramlink id="request_list"></paramlink> array.
1753         Any thread suspended through
1754         a <jvmti/> suspend function (eg.
1755         <functionlink id="SuspendThreadList"></functionlink>)
1756         or <code>java.lang.Thread.suspend()</code>
1757         will resume execution.
1758       </description>
1759       <origin>jvmdi</origin>
1760       <capabilities>
1761         <required id="can_suspend"></required>
1762       </capabilities>
1763       <parameters>
1764         <param id="request_count">
1765           <jint min="0"/>
1766           <description>
1767             The number of threads to resume.
1768           </description>
1769         </param>
1770         <param id="request_list">
1771           <inbuf incount="request_count"><jthread/></inbuf>
1772             <description>
1773               The threads to resume.
1774             </description>
1775         </param>
1776         <param id="results">
1777           <outbuf incount="request_count"><enum>jvmtiError</enum></outbuf>
1778           <description>
1779             An agent supplied array of
1780             <paramlink id="request_count"></paramlink> elements.
1781             On return, filled with the error code for
1782             the resume of the corresponding thread.
1783             The error code will be
1784             <errorlink id="JVMTI_ERROR_NONE"></errorlink>
1785             if the thread was suspended by this call.
1786             Possible error codes are those specified
1787             for <functionlink id="ResumeThread"></functionlink>.
1788           </description>
1789         </param>
1790       </parameters>
1791       <errors>
1792       </errors>
1793     </function>
1794 
1795     <function id="StopThread" num="7">
1796       <synopsis>Stop Thread</synopsis>
1797       <description>
1798         Send the specified asynchronous exception to the specified thread.
1799         Normally, this function is used to kill the specified thread with an
1800         instance of the exception <code>ThreadDeath</code>, similar to
1801         <code>java.lang.Thread.stop</code>.
1802       </description>
1803       <origin>jvmdi</origin>
1804       <capabilities>
1805         <required id="can_signal_thread"></required>
1806       </capabilities>
1807       <parameters>
1808         <param id="thread">
1809           <jthread/>
1810             <description>
1811               The thread to stop.
1812             </description>
1813         </param>
1814         <param id="exception">
1815           <jobject/>
1816             <description>
1817               The asynchronous exception object.
1818             </description>
1819         </param>
1820       </parameters>
1821       <errors>
1822       </errors>
1823     </function>
1824 
1825     <function id="InterruptThread" num="8">
1826       <synopsis>Interrupt Thread</synopsis>
1827       <description>
1828         Interrupt the specified thread
1829         (similar to <code>java.lang.Thread.interrupt</code>).
1830       </description>
1831       <origin>jvmdi</origin>
1832       <capabilities>
1833         <required id="can_signal_thread"></required>
1834       </capabilities>
1835       <parameters>
1836         <param id="thread">
1837           <jthread impl="noconvert"/>
1838             <description>
1839               The thread to interrupt.
1840             </description>
1841         </param>
1842       </parameters>
1843       <errors>
1844       </errors>
1845     </function>
1846 
1847     <function id="GetThreadInfo" num="9">
1848       <synopsis>Get Thread Info</synopsis>
1849       <typedef id="jvmtiThreadInfo" label="Thread information structure">
1850         <field id="name">
1851           <allocfieldbuf><char/></allocfieldbuf>
1852           <description>
1853             The thread name, encoded as a
1854             <internallink id="mUTF">modified UTF-8</internallink> string.
1855           </description>
1856         </field>
1857         <field id="priority">
1858           <jint/>
1859           <description>
1860             The thread priority.  See the thread priority constants:
1861             <datalink id="jvmtiThreadPriority"></datalink>.
1862           </description>
1863         </field>
1864         <field id="is_daemon">
1865           <jboolean/>
1866           <description>
1867             Is this a daemon thread?
1868           </description>
1869         </field>
1870         <field id="thread_group">
1871           <jthreadGroup/>
1872           <description>
1873             The thread group to which this thread belongs.
1874             <code>NULL</code> if the thread has died.
1875           </description>
1876         </field>
1877         <field id="context_class_loader">
1878           <jobject/>
1879             <description>
1880               The context class loader associated with this thread.
1881             </description>
1882         </field>
1883       </typedef>
1884       <description>
1885         Get thread information. The fields of the <datalink id="jvmtiThreadInfo"/> structure
1886         are filled in with details of the specified thread.
1887       </description>
1888       <origin>jvmdi</origin>
1889       <capabilities>
1890       </capabilities>
1891       <parameters>
1892         <param id="thread">
1893           <jthread null="current" impl="noconvert" started="maybe"/>
1894             <description>
1895               The thread to query.
1896             </description>
1897         </param>
1898         <param id="info_ptr">
1899           <outptr><struct>jvmtiThreadInfo</struct></outptr>
1900           <description>
1901             On return, filled with information describing the specified thread.
1902           </description>
1903         </param>
1904       </parameters>
1905       <errors>
1906       </errors>
1907     </function>
1908 
1909     <function id="GetOwnedMonitorInfo" num="10">
1910       <synopsis>Get Owned Monitor Info</synopsis>
1911       <description>
1912         Get information about the monitors owned by the
1913         specified thread.
1914       </description>
1915       <origin>jvmdiClone</origin>
1916       <capabilities>
1917         <required id="can_get_owned_monitor_info"></required>
1918       </capabilities>
1919       <parameters>
1920         <param id="thread">
1921           <jthread null="current"/>
1922             <description>
1923               The thread to query.
1924             </description>
1925         </param>
1926         <param id="owned_monitor_count_ptr">
1927           <outptr><jint/></outptr>
1928           <description>
1929             The number of monitors returned.
1930           </description>
1931         </param>
1932         <param id="owned_monitors_ptr">
1933           <allocbuf outcount="owned_monitor_count_ptr"><jobject/></allocbuf>
1934             <description>
1935               The array of owned monitors.
1936             </description>
1937         </param>
1938       </parameters>
1939       <errors>
1940       </errors>
1941     </function>
1942 
1943     <function id="GetOwnedMonitorStackDepthInfo" num="153" since="1.1">
1944       <synopsis>Get Owned Monitor Stack Depth Info</synopsis>
1945       <typedef id="jvmtiMonitorStackDepthInfo"
1946                label="Monitor stack depth information structure">
1947         <field id="monitor">
1948           <jobject/>
1949             <description>
1950               The owned monitor.
1951             </description>
1952         </field>
1953         <field id="stack_depth">
1954           <jint/>
1955           <description>
1956             The stack depth.  Corresponds to the stack depth used in the
1957             <internallink id="stack">Stack Frame functions</internallink>.
1958             That is, zero is the current frame, one is the frame which
1959             called the current frame. And it is negative one if the
1960             implementation cannot determine the stack depth (e.g., for
1961             monitors acquired by JNI <code>MonitorEnter</code>).
1962           </description>
1963         </field>
1964       </typedef>
1965       <description>
1966         Get information about the monitors owned by the
1967         specified thread and the depth of the stack frame which locked them.
1968       </description>
1969       <origin>new</origin>
1970       <capabilities>
1971         <required id="can_get_owned_monitor_stack_depth_info"></required>
1972       </capabilities>
1973       <parameters>
1974         <param id="thread">
1975           <jthread null="current"/>
1976             <description>
1977               The thread to query.
1978             </description>
1979         </param>
1980         <param id="monitor_info_count_ptr">
1981           <outptr><jint/></outptr>
1982           <description>
1983             The number of monitors returned.
1984           </description>
1985         </param>
1986         <param id="monitor_info_ptr">
1987           <allocbuf outcount="monitor_info_count_ptr">
1988             <struct>jvmtiMonitorStackDepthInfo</struct>
1989           </allocbuf>
1990           <description>
1991             The array of owned monitor depth information.
1992           </description>
1993         </param>
1994       </parameters>
1995       <errors>
1996       </errors>
1997     </function>
1998 
1999     <function id="GetCurrentContendedMonitor" num="11">
2000       <synopsis>Get Current Contended Monitor</synopsis>
2001       <description>
2002         Get the object, if any, whose monitor the specified thread is waiting to
2003         enter or waiting to regain through <code>java.lang.Object.wait</code>.
2004       </description>
2005       <origin>jvmdi</origin>
2006       <capabilities>
2007         <required id="can_get_current_contended_monitor"></required>
2008       </capabilities>
2009       <parameters>
2010         <param id="thread">
2011           <jthread null="current"/>
2012             <description>
2013               The thread to query.
2014             </description>
2015         </param>
2016         <param id="monitor_ptr">
2017           <outptr><jobject/></outptr>
2018             <description>
2019               On return, filled with the current contended monitor, or
2020               NULL if there is none.
2021             </description>
2022         </param>
2023       </parameters>
2024       <errors>
2025       </errors>
2026     </function>
2027 
2028     <callback id="jvmtiStartFunction">
2029       <void/>
2030       <synopsis>Agent Start Function</synopsis>
2031       <description>
2032         Agent supplied callback function.
2033         This function is the entry point for an agent thread
2034         started with
2035         <functionlink id="RunAgentThread"></functionlink>.
2036       </description>
2037       <parameters>
2038           <param id="jvmti_env">
2039             <outptr>
2040               <struct>jvmtiEnv</struct>
2041             </outptr>
2042             <description>
2043               The <jvmti/> environment.
2044             </description>
2045           </param>
2046           <param id="jni_env">
2047             <outptr>
2048               <struct>JNIEnv</struct>
2049             </outptr>
2050             <description>
2051               The JNI environment.
2052             </description>
2053           </param>
2054           <param id="arg">
2055             <outptr>
2056               <void/>
2057             </outptr>
2058               <description>
2059                 The <code>arg</code> parameter passed to
2060                 <functionlink id="RunAgentThread"></functionlink>.
2061               </description>
2062           </param>
2063       </parameters>
2064     </callback>
2065 
2066     <function id="RunAgentThread" num="12">
2067       <synopsis>Run Agent Thread</synopsis>
2068       <description>
2069         Starts the execution of an agent thread. with the specified native function.
2070         The parameter <paramlink id="arg"></paramlink> is forwarded on to the
2071         <functionlink id="jvmtiStartFunction">start function</functionlink>
2072         (specified with <paramlink id="proc"></paramlink>) as its single argument.
2073         This function allows the creation of agent threads
2074         for handling communication with another process or for handling events
2075         without the need to load a special subclass of <code>java.lang.Thread</code> or
2076         implementer of <code>java.lang.Runnable</code>.
2077         Instead, the created thread can run entirely in native code.
2078         However, the created thread does require a newly created instance
2079         of <code>java.lang.Thread</code> (referenced by the argument <code>thread</code>) to
2080         which it will be associated.
2081         The thread object can be created with JNI calls.
2082         <p/>
2083         The following common thread priorities are provided for your convenience:
2084         <constants id="jvmtiThreadPriority" label="Thread Priority Constants" kind="const">
2085           <constant id="JVMTI_THREAD_MIN_PRIORITY" num="1">
2086             Minimum possible thread priority
2087           </constant>
2088           <constant id="JVMTI_THREAD_NORM_PRIORITY" num="5">
2089             Normal thread priority
2090           </constant>
2091           <constant id="JVMTI_THREAD_MAX_PRIORITY" num="10">
2092             Maximum possible thread priority
2093           </constant>
2094         </constants>
2095         <p/>
2096         The new thread is started as a daemon thread with the specified
2097         <paramlink id="priority"></paramlink>.
2098         If enabled, a <eventlink id="ThreadStart"/> event will be sent.
2099         <p/>
2100         Since the thread has been started, the thread will be live when this function
2101         returns, unless the thread has died immediately.
2102         <p/>
2103         The thread group of the thread is ignored -- specifically, the thread is not
2104         added to the thread group and the thread is not seen on queries of the thread
2105         group at either the Java programming language or <jvmti/> levels.
2106         <p/>
2107         The thread is not visible to Java programming language queries but is
2108         included in <jvmti/> queries (for example,
2109         <functionlink id="GetAllThreads"/> and
2110         <functionlink id="GetAllStackTraces"/>).
2111         <p/>
2112         Upon execution of <code>proc</code>, the new thread will be attached to the
2113         VM -- see the JNI documentation on
2114         <externallink id="jni/invocation.html#attaching-to-the-vm"
2115                       >Attaching to the VM</externallink>.
2116       </description>
2117       <origin>jvmdiClone</origin>
2118       <capabilities>
2119       </capabilities>
2120       <parameters>
2121         <param id="thread">
2122           <jthread impl="noconvert" started="no"/>
2123             <description>
2124               The thread to run.
2125             </description>
2126         </param>
2127         <param id="proc">
2128           <ptrtype>
2129             <struct>jvmtiStartFunction</struct>
2130           </ptrtype>
2131           <description>
2132             The start function.
2133           </description>
2134         </param>
2135         <param id="arg">
2136           <inbuf>
2137             <void/>
2138             <nullok><code>NULL</code> is passed to the start function</nullok>
2139           </inbuf>
2140           <description>
2141             The argument to the start function.
2142           </description>
2143         </param>
2144         <param id="priority">
2145           <jint/>
2146           <description>
2147             The priority of the started thread. Any thread
2148             priority allowed by <code>java.lang.Thread.setPriority</code> can be used including
2149             those in <datalink id="jvmtiThreadPriority"></datalink>.
2150           </description>
2151         </param>
2152       </parameters>
2153       <errors>
2154         <error id="JVMTI_ERROR_INVALID_PRIORITY">
2155             <paramlink id="priority"/> is less than
2156             <datalink id="JVMTI_THREAD_MIN_PRIORITY"/>
2157               or greater than
2158             <datalink id="JVMTI_THREAD_MAX_PRIORITY"/>
2159         </error>
2160       </errors>
2161     </function>
2162 
2163     <function id="SetThreadLocalStorage" jkernel="yes" impl="notrace" phase="start" num="103">
2164       <synopsis>Set Thread Local Storage</synopsis>
2165       <description>
2166         The VM stores a pointer value associated with each environment-thread
2167         pair. This pointer value is called <i>thread-local storage</i>.
2168         This value is <code>NULL</code> unless set with this function.
2169         Agents can allocate memory in which they store thread specific
2170         information. By setting thread-local storage it can then be
2171         accessed with
2172         <functionlink id="GetThreadLocalStorage"></functionlink>.
2173         <p/>
2174         This function is called by the agent to set the value of the <jvmti/>
2175         thread-local storage. <jvmti/> supplies to the agent a pointer-size
2176         thread-local storage that can be used to record per-thread
2177         information.
2178       </description>
2179       <origin>jvmpi</origin>
2180       <capabilities>
2181       </capabilities>
2182       <parameters>
2183         <param id="thread">
2184           <jthread null="current"/>
2185             <description>
2186               Store to this thread.
2187             </description>
2188         </param>
2189         <param id="data">
2190           <inbuf>
2191             <void/>
2192             <nullok>value is set to <code>NULL</code></nullok>
2193           </inbuf>
2194           <description>
2195             The value to be entered into the thread-local storage.
2196           </description>
2197         </param>
2198       </parameters>
2199       <errors>
2200       </errors>
2201     </function>
2202 
2203     <function id="GetThreadLocalStorage" jkernel="yes" impl="innative notrace" phase="start" num="102">
2204       <synopsis>Get Thread Local Storage</synopsis>
2205       <description>
2206         Called by the agent to get the value of the <jvmti/> thread-local
2207         storage.
2208       </description>
2209       <origin>jvmpi</origin>
2210       <capabilities>
2211       </capabilities>
2212       <parameters>
2213         <param id="thread">
2214           <jthread null="current" impl="noconvert"/>
2215             <description>
2216               Retrieve from this thread.
2217             </description>
2218         </param>
2219         <param id="data_ptr">
2220           <agentbuf><void/></agentbuf>
2221           <description>
2222             Pointer through which the value of the thread local
2223             storage is returned.
2224             If thread-local storage has not been set with
2225             <functionlink id="SetThreadLocalStorage"></functionlink> the returned
2226             pointer is <code>NULL</code>.
2227           </description>
2228         </param>
2229       </parameters>
2230       <errors>
2231       </errors>
2232     </function>
2233 
2234   </category>
2235 
2236   <category id="thread_groups" label="Thread Group">
2237     <intro>
2238     </intro>
2239 
2240     <function id="GetTopThreadGroups" num="13">
2241       <synopsis>Get Top Thread Groups</synopsis>
2242       <description>
2243         Return all top-level (parentless) thread groups in the VM.
2244       </description>
2245       <origin>jvmdi</origin>
2246       <capabilities>
2247       </capabilities>
2248       <parameters>
2249         <param id="group_count_ptr">
2250           <outptr><jint/></outptr>
2251           <description>
2252             On return, points to the number of top-level thread groups.
2253           </description>
2254         </param>
2255         <param id="groups_ptr">
2256           <allocbuf outcount="group_count_ptr"><jthreadGroup/></allocbuf>
2257             <description>
2258               On return, refers to a pointer to the top-level thread group array.
2259             </description>
2260         </param>
2261       </parameters>
2262       <errors>
2263       </errors>
2264     </function>
2265 
2266     <function id="GetThreadGroupInfo" num="14">
2267       <synopsis>Get Thread Group Info</synopsis>
2268       <typedef id="jvmtiThreadGroupInfo" label="Thread group information structure">
2269         <field id="parent">
2270           <jthreadGroup/>
2271           <description>
2272             The parent thread group.
2273           </description>
2274         </field>
2275         <field id="name">
2276           <allocfieldbuf><char/></allocfieldbuf>
2277           <description>
2278             The thread group's name, encoded as a
2279             <internallink id="mUTF">modified UTF-8</internallink> string.
2280           </description>
2281         </field>
2282         <field id="max_priority">
2283           <jint/>
2284           <description>
2285             The maximum priority for this thread group.
2286           </description>
2287         </field>
2288         <field id="is_daemon">
2289           <jboolean/>
2290           <description>
2291             Is this a daemon thread group?
2292           </description>
2293         </field>
2294       </typedef>
2295       <description>
2296         Get information about the thread group. The fields of the
2297         <functionlink id="jvmtiThreadGroupInfo"></functionlink> structure
2298         are filled in with details of the specified thread group.
2299       </description>
2300       <origin>jvmdi</origin>
2301       <capabilities>
2302       </capabilities>
2303       <parameters>
2304         <param id="group">
2305           <jthreadGroup/>
2306           <description>
2307             The thread group to query.
2308           </description>
2309         </param>
2310         <param id="info_ptr">
2311           <outptr><struct>jvmtiThreadGroupInfo</struct></outptr>
2312           <description>
2313             On return, filled with information describing the specified
2314             thread group.
2315           </description>
2316         </param>
2317       </parameters>
2318       <errors>
2319       </errors>
2320     </function>
2321 
2322     <function id="GetThreadGroupChildren" num="15">
2323       <synopsis>Get Thread Group Children</synopsis>
2324       <description>
2325         Get the live threads and active subgroups in this thread group.
2326       </description>
2327       <origin>jvmdi</origin>
2328       <capabilities>
2329       </capabilities>
2330       <parameters>
2331         <param id="group">
2332           <jthreadGroup/>
2333           <description>
2334             The group to query.
2335           </description>
2336         </param>
2337         <param id="thread_count_ptr">
2338           <outptr><jint/></outptr>
2339           <description>
2340             On return, points to the number of live threads in this thread group.
2341           </description>
2342         </param>
2343         <param id="threads_ptr">
2344           <allocbuf outcount="thread_count_ptr"><jthread/></allocbuf>
2345             <description>
2346               On return, points to an array of the live threads in this thread group.
2347             </description>
2348         </param>
2349         <param id="group_count_ptr">
2350           <outptr><jint/></outptr>
2351           <description>
2352             On return, points to the number of active child thread groups
2353           </description>
2354         </param>
2355         <param id="groups_ptr">
2356           <allocbuf outcount="group_count_ptr"><jthreadGroup/></allocbuf>
2357             <description>
2358               On return, points to an array of the active child thread groups.
2359             </description>
2360         </param>
2361       </parameters>
2362       <errors>
2363       </errors>
2364     </function>
2365   </category>
2366 
2367   <category id="stack" label="Stack Frame">
2368     <intro>
2369         These functions provide information about the stack of a thread.
2370         Stack frames are referenced by depth.
2371         The frame at depth zero is the current frame.
2372         <p/>
2373         Stack frames are as described in
2374         <vmspec chapter="3.6"/>,
2375         That is, they correspond to method
2376         invocations (including native methods) but do not correspond to platform native or
2377         VM internal frames.
2378         <p/>
2379         A <jvmti/> implementation may use method invocations to launch a thread and
2380         the corresponding frames may be included in the stack as presented by these functions --
2381         that is, there may be frames shown
2382         deeper than <code>main()</code> and <code>run()</code>.
2383         However this presentation must be consistent across all <jvmti/> functionality which
2384         uses stack frames or stack depth.
2385     </intro>
2386 
2387       <typedef id="jvmtiFrameInfo" label="Stack frame information structure">
2388         <description>
2389           Information about a stack frame is returned in this structure.
2390         </description>
2391         <field id="method">
2392           <jmethodID/>
2393             <description>
2394               The method executing in this frame.
2395             </description>
2396         </field>
2397         <field id="location">
2398           <jlocation/>
2399           <description>
2400             The index of the instruction executing in this frame.
2401             <code>-1</code> if the frame is executing a native method.
2402           </description>
2403         </field>
2404       </typedef>
2405 
2406       <typedef id="jvmtiStackInfo" label="Stack information structure">
2407         <description>
2408           Information about a set of stack frames is returned in this structure.
2409         </description>
2410         <field id="thread">
2411           <jthread/>
2412           <description>
2413             On return, the thread traced.
2414           </description>
2415         </field>
2416         <field id="state">
2417           <jint/>
2418           <description>
2419             On return, the thread state. See <functionlink id="GetThreadState"></functionlink>.
2420           </description>
2421         </field>
2422         <field id="frame_buffer">
2423           <outbuf incount="max_frame_count">
2424             <struct>jvmtiFrameInfo</struct>
2425           </outbuf>
2426             <description>
2427               On return, this agent allocated buffer is filled
2428               with stack frame information.
2429             </description>
2430         </field>
2431         <field id="frame_count">
2432           <jint/>
2433           <description>
2434             On return, the number of records filled into
2435             <code>frame_buffer</code>.
2436             This will be
2437             min(<code>max_frame_count</code>, <i>stackDepth</i>).
2438           </description>
2439         </field>
2440       </typedef>
2441 
2442     <function id="GetStackTrace" num="104">
2443       <synopsis>Get Stack Trace</synopsis>
2444       <description>
2445         Get information about the stack of a thread.
2446         If <paramlink id="max_frame_count"></paramlink> is less than the depth of the stack,
2447         the <paramlink id="max_frame_count"></paramlink> topmost frames are returned,
2448         otherwise the entire stack is returned.
2449         The topmost frames, those most recently invoked, are at the beginning of the returned buffer.
2450         <p/>
2451         The following example causes up to five of the topmost frames
2452         to be returned and (if there are any frames) the currently
2453         executing method name to be printed.
2454         <example>
2455 jvmtiFrameInfo frames[5];
2456 jint count;
2457 jvmtiError err;
2458 
2459 err = (*jvmti)-&gt;GetStackTrace(jvmti, aThread, 0, 5,
2460                                frames, &amp;count);
2461 if (err == JVMTI_ERROR_NONE &amp;&amp; count &gt;= 1) {
2462    char *methodName;
2463    err = (*jvmti)-&gt;GetMethodName(jvmti, frames[0].method,
2464                        &amp;methodName, NULL, NULL);
2465    if (err == JVMTI_ERROR_NONE) {
2466       printf("Executing method: %s", methodName);
2467    }
2468 }
2469         </example>
2470         <todo>
2471           check example code.
2472         </todo>
2473         <p/>
2474         The <paramlink id="thread"></paramlink> need not be suspended
2475         to call this function.
2476         <p/>
2477         The <functionlink id="GetLineNumberTable"></functionlink>
2478         function can be used to map locations to line numbers. Note that
2479         this mapping can be done lazily.
2480       </description>
2481       <origin>jvmpi</origin>
2482       <capabilities>
2483       </capabilities>
2484       <parameters>
2485         <param id="thread">
2486           <jthread null="current"/>
2487             <description>
2488               Fetch the stack trace of this thread.
2489             </description>
2490         </param>
2491         <param id="start_depth">
2492           <jint/>
2493           <description>
2494             Begin retrieving frames at this depth.
2495             If non-negative, count from the current frame,
2496             the first frame retrieved is at depth <code>start_depth</code>.
2497             For example, if zero, start from the current frame; if one, start from the
2498             caller of the current frame; if two, start from the caller of the
2499             caller of the current frame; and so on.
2500             If negative, count from below the oldest frame,
2501             the first frame retrieved is at depth <i>stackDepth</i><code> + start_depth</code>,
2502             where <i>stackDepth</i> is the count of frames on the stack.
2503             For example, if negative one, only the oldest frame is retrieved;
2504             if negative two, start from the frame called by the oldest frame.
2505           </description>
2506         </param>
2507         <param id="max_frame_count">
2508           <jint min="0"/>
2509           <description>
2510             The maximum number of <datalink id="jvmtiFrameInfo"/> records to retrieve.
2511           </description>
2512         </param>
2513         <param id="frame_buffer">
2514           <outbuf incount="max_frame_count" outcount="count_ptr">
2515             <struct>jvmtiFrameInfo</struct>
2516           </outbuf>
2517             <description>
2518               On return, this agent allocated buffer is filled
2519               with stack frame information.
2520             </description>
2521         </param>
2522         <param id="count_ptr">
2523           <outptr><jint/></outptr>
2524           <description>
2525             On return, points to the number of records filled in.
2526             For non-negative <code>start_depth</code>, this will be
2527             min(<code>max_frame_count</code>, <i>stackDepth</i><code> - start_depth</code>).
2528             For negative <code>start_depth</code>, this will be
2529             min(<code>max_frame_count</code>, <code>-start_depth</code>).
2530           </description>
2531         </param>
2532       </parameters>
2533       <errors>
2534         <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
2535           <paramlink id="start_depth"/> is positive and greater than or equal to <i>stackDepth</i>.
2536           Or <paramlink id="start_depth"/> is negative and less than <i>-stackDepth</i>.
2537         </error>
2538       </errors>
2539     </function>
2540 
2541 
2542     <function id="GetAllStackTraces" num="100">
2543       <synopsis>Get All Stack Traces</synopsis>
2544       <description>
2545         Get information about the stacks of all live threads
2546         (including <internallink id="RunAgentThread">agent threads</internallink>).
2547         If <paramlink id="max_frame_count"/> is less than the depth of a stack,
2548         the <paramlink id="max_frame_count"/> topmost frames are returned for that thread,
2549         otherwise the entire stack is returned.
2550         The topmost frames, those most recently invoked, are at the beginning of the returned buffer.
2551         <p/>
2552         All stacks are collected simultaneously, that is, no changes will occur to the
2553         thread state or stacks between the sampling of one thread and the next.
2554         The threads need not be suspended.
2555 
2556         <example>
2557 jvmtiStackInfo *stack_info;
2558 jint thread_count;
2559 int ti;
2560 jvmtiError err;
2561 
2562 err = (*jvmti)-&gt;GetAllStackTraces(jvmti, MAX_FRAMES, &amp;stack_info, &amp;thread_count);
2563 if (err != JVMTI_ERROR_NONE) {
2564    ...
2565 }
2566 for (ti = 0; ti &lt; thread_count; ++ti) {
2567    jvmtiStackInfo *infop = &amp;stack_info[ti];
2568    jthread thread = infop-&gt;thread;
2569    jint state = infop-&gt;state;
2570    jvmtiFrameInfo *frames = infop-&gt;frame_buffer;
2571    int fi;
2572 
2573    myThreadAndStatePrinter(thread, state);
2574    for (fi = 0; fi &lt; infop-&gt;frame_count; fi++) {
2575       myFramePrinter(frames[fi].method, frames[fi].location);
2576    }
2577 }
2578 /* this one Deallocate call frees all data allocated by GetAllStackTraces */
2579 err = (*jvmti)-&gt;Deallocate(jvmti, stack_info);
2580         </example>
2581         <todo>
2582           check example code.
2583         </todo>
2584 
2585       </description>
2586       <origin>new</origin>
2587       <capabilities>
2588       </capabilities>
2589       <parameters>
2590         <param id="max_frame_count">
2591           <jint min="0"/>
2592           <description>
2593             The maximum number of <datalink id="jvmtiFrameInfo"/> records to retrieve per thread.
2594           </description>
2595         </param>
2596         <param id="stack_info_ptr">
2597           <allocbuf>
2598             <struct>jvmtiStackInfo</struct>
2599           </allocbuf>
2600             <description>
2601               On return, this buffer is filled
2602               with stack information for each thread.
2603               The number of <datalink id="jvmtiStackInfo"/> records is determined
2604               by <paramlink id="thread_count_ptr"/>.
2605               <p/>
2606               Note that this buffer is allocated to include the <datalink id="jvmtiFrameInfo"/>
2607               buffers pointed to by <datalink id="jvmtiStackInfo.frame_buffer"/>.
2608               These buffers must not be separately deallocated.
2609             </description>
2610         </param>
2611         <param id="thread_count_ptr">
2612           <outptr><jint/></outptr>
2613           <description>
2614             The number of threads traced.
2615           </description>
2616         </param>
2617       </parameters>
2618       <errors>
2619       </errors>
2620     </function>
2621 
2622     <function id="GetThreadListStackTraces" num="101">
2623       <synopsis>Get Thread List Stack Traces</synopsis>
2624       <description>
2625         Get information about the stacks of the supplied threads.
2626         If <paramlink id="max_frame_count"/> is less than the depth of a stack,
2627         the <paramlink id="max_frame_count"/> topmost frames are returned for that thread,
2628         otherwise the entire stack is returned.
2629         The topmost frames, those most recently invoked, are at the beginning of the returned buffer.
2630         <p/>
2631         All stacks are collected simultaneously, that is, no changes will occur to the
2632         thread state or stacks between the sampling one thread and the next.
2633         The threads need not be suspended.
2634         <p/>
2635         If a thread has not yet started or terminates before the stack information is collected,
2636         a zero length stack (<datalink id="jvmtiStackInfo.frame_count"/> will be zero)
2637         will be returned and the thread <datalink id="jvmtiStackInfo.state"/> can be checked.
2638         <p/>
2639         See the example for the similar function
2640         <functionlink id="GetAllStackTraces"/>.
2641       </description>
2642       <origin>new</origin>
2643       <capabilities>
2644       </capabilities>
2645       <parameters>
2646         <param id="thread_count">
2647           <jint min="0"/>
2648           <description>
2649             The number of threads to trace.
2650           </description>
2651         </param>
2652         <param id="thread_list">
2653           <inbuf incount="thread_count"><jthread/></inbuf>
2654             <description>
2655               The list of threads to trace.
2656             </description>
2657         </param>
2658         <param id="max_frame_count">
2659           <jint min="0"/>
2660           <description>
2661             The maximum number of <datalink id="jvmtiFrameInfo"/> records to retrieve per thread.
2662           </description>
2663         </param>
2664         <param id="stack_info_ptr">
2665           <allocbuf outcount="thread_count">
2666             <struct>jvmtiStackInfo</struct>
2667           </allocbuf>
2668             <description>
2669               On return, this buffer is filled
2670               with stack information for each thread.
2671               The number of <datalink id="jvmtiStackInfo"/> records is determined
2672               by <paramlink id="thread_count"/>.
2673               <p/>
2674               Note that this buffer is allocated to include the <datalink id="jvmtiFrameInfo"/>
2675               buffers pointed to by <datalink id="jvmtiStackInfo.frame_buffer"/>.
2676               These buffers must not be separately deallocated.
2677             </description>
2678         </param>
2679       </parameters>
2680       <errors>
2681         <error id="JVMTI_ERROR_INVALID_THREAD">
2682           An element in <paramlink id="thread_list"/> is not a thread object.
2683         </error>
2684       </errors>
2685     </function>
2686 
2687     <elide>
2688     <function id="AsyncGetStackTrace" num="1000">
2689       <synopsis>Get Stack Trace--Asynchronous</synopsis>
2690       <description>
2691         Get information about the entire stack of a thread (or a sub-section of it).
2692         This is the asynchronous version of <functionlink id="GetStackTrace"></functionlink>
2693         and is reentrant and safe to call
2694         from asynchronous signal handlers.
2695         The stack trace is returned only for the calling thread.
2696         <p/>
2697         The <functionlink id="GetLineNumberTable"></functionlink>
2698         function can be used to map locations to line numbers. Note that
2699         this mapping can be done lazily.
2700       </description>
2701       <origin>jvmpi</origin>
2702       <capabilities>
2703         <required id="can_get_async_stack_trace"></required>
2704         <capability id="can_show_JVM_spec_async_frames">
2705           If <code>false</code>,
2706           <paramlink id="use_java_stack"></paramlink>
2707           must be <code>false</code>.
2708         </capability>
2709       </capabilities>
2710       <parameters>
2711         <param id="use_java_stack">
2712           <jboolean/>
2713           <description>
2714             Return the stack showing <vmspec/>
2715             model of the stack;
2716             otherwise, show the internal representation of the stack with
2717             inlined and optimized methods missing.  If the virtual machine
2718             is using the <i>Java Virtual Machine Specification</i> stack model
2719             internally, this flag is ignored.
2720           </description>
2721         </param>
2722         <param id="max_count">
2723           <jint min="0"/>
2724           <description>
2725             The maximum number of <datalink id="jvmtiFrameInfo"/> records to retrieve.
2726             Retrieve this many unless the stack depth is less than <code>max_count</code>.
2727           </description>
2728         </param>
2729         <param id="frame_buffer">
2730           <outbuf incount="max_count" outcount="count_ptr">
2731             <struct>jvmtiFrameInfo</struct>
2732             <nullok>this information is not returned</nullok>
2733           </outbuf>
2734             <description>
2735               The agent passes in a buffer
2736               large enough to hold <code>max_count</code> records of
2737               <datalink id="jvmtiFrameInfo"></datalink>.  This buffer must be
2738               pre-allocated by the agent.
2739             </description>
2740         </param>
2741         <param id="count_ptr">
2742           <outptr><jint/></outptr>
2743           <description>
2744             On return, points to the number of records filled in..
2745           </description>
2746         </param>
2747       </parameters>
2748       <errors>
2749         <error id="JVMTI_ERROR_UNATTACHED_THREAD">
2750           The thread being used to call this function is not attached
2751           to the virtual machine.  Calls must be made from attached threads.
2752         </error>
2753       </errors>
2754     </function>
2755     </elide>
2756 
2757     <function id="GetFrameCount" num="16">
2758       <synopsis>Get Frame Count</synopsis>
2759       <description>
2760         Get the number of frames currently in the specified thread's call stack.
2761         <p/>
2762         If this function is called for a thread actively executing bytecodes (for example,
2763         not the current thread and not suspended), the information returned is transient.
2764       </description>
2765       <origin>jvmdi</origin>
2766       <capabilities>
2767       </capabilities>
2768       <parameters>
2769         <param id="thread">
2770           <jthread null="current"/>
2771             <description>
2772               The thread to query.
2773             </description>
2774         </param>
2775         <param id="count_ptr">
2776           <outptr><jint/></outptr>
2777           <description>
2778             On return, points to the number of frames in the call stack.
2779           </description>
2780         </param>
2781       </parameters>
2782       <errors>
2783       </errors>
2784     </function>
2785 
2786     <function id="PopFrame" num="80">
2787       <synopsis>Pop Frame</synopsis>
2788       <description>
2789         Pop the current frame of <code>thread</code>'s stack.
2790         Popping a frame takes you to the previous frame.
2791         When the thread is resumed, the execution
2792         state of the thread is reset to the state
2793         immediately before the called method was invoked.
2794         That is (using <vmspec/> terminology):
2795           <ul>
2796             <li>the current frame is discarded as the previous frame becomes the current one</li>
2797             <li>the operand stack is restored--the argument values are added back
2798               and if the invoke was not <code>invokestatic</code>,
2799               <code>objectref</code> is added back as well</li>
2800             <li>the Java virtual machine PC is restored to the opcode
2801               of the invoke instruction</li>
2802           </ul>
2803         Note however, that any changes to the arguments, which
2804         occurred in the called method, remain;
2805         when execution continues, the first instruction to
2806         execute will be the invoke.
2807         <p/>
2808         Between calling <code>PopFrame</code> and resuming the
2809         thread the state of the stack is undefined.
2810         To pop frames beyond the first,
2811         these three steps must be repeated:
2812         <ul>
2813           <li>suspend the thread via an event (step, breakpoint, ...)</li>
2814           <li>call <code>PopFrame</code></li>
2815           <li>resume the thread</li>
2816         </ul>
2817         <p/>
2818         A lock acquired by calling the called method
2819         (if it is a <code>synchronized</code>  method)
2820         and locks acquired by entering <code>synchronized</code>
2821         blocks within the called method are released.
2822         Note: this does not apply to native locks or
2823         <code>java.util.concurrent.locks</code> locks.
2824         <p/>
2825         Finally blocks are not executed.
2826         <p/>
2827         Changes to global state are not addressed and thus remain changed.
2828         <p/>
2829         The specified thread must be suspended or must be the current thread.
2830         <p/>
2831         Both the called method and calling method must be non-native Java programming
2832         language methods.
2833         <p/>
2834         No <jvmti/> events are generated by this function.
2835       </description>
2836       <origin>jvmdi</origin>
2837       <capabilities>
2838         <required id="can_pop_frame"></required>
2839       </capabilities>
2840       <parameters>
2841         <param id="thread">
2842           <jthread/>
2843             <description>
2844               The thread whose current frame is to be popped.
2845             </description>
2846         </param>
2847       </parameters>
2848       <errors>
2849         <error id="JVMTI_ERROR_OPAQUE_FRAME">
2850           Called or calling method is a native method.
2851           The implementation is unable to pop this frame.
2852         </error>
2853         <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
2854           Thread was not suspended and was not the current thread.
2855         </error>
2856         <error id="JVMTI_ERROR_NO_MORE_FRAMES">
2857           There are less than two stack frames on the call stack.
2858         </error>
2859       </errors>
2860     </function>
2861 
2862     <function id="GetFrameLocation" num="19">
2863       <synopsis>Get Frame Location</synopsis>
2864       <description>
2865         <p/>
2866         For a Java programming language frame, return the location of the instruction
2867         currently executing.
2868       </description>
2869       <origin>jvmdiClone</origin>
2870       <capabilities>
2871       </capabilities>
2872       <parameters>
2873         <param id="thread">
2874           <jthread null="current" frame="frame"/>
2875           <description>
2876             The thread of the frame to query.
2877           </description>
2878         </param>
2879         <param id="depth">
2880           <jframeID thread="thread"/>
2881           <description>
2882             The depth of the frame to query.
2883           </description>
2884         </param>
2885         <param id="method_ptr">
2886           <outptr><jmethodID/></outptr>
2887             <description>
2888               On return, points to the method for the current location.
2889             </description>
2890         </param>
2891         <param id="location_ptr">
2892           <outptr><jlocation/></outptr>
2893           <description>
2894             On return, points to the index of the currently
2895             executing instruction.
2896             Is set to <code>-1</code> if the frame is executing
2897             a native method.
2898           </description>
2899         </param>
2900       </parameters>
2901       <errors>
2902       </errors>
2903     </function>
2904 
2905     <function id="NotifyFramePop" num="20">
2906       <synopsis>Notify Frame Pop</synopsis>
2907       <description>
2908         When the frame that is currently at <paramlink id="depth"></paramlink>
2909         is popped from the stack, generate a
2910         <eventlink id="FramePop"></eventlink> event.  See the
2911         <eventlink id="FramePop"></eventlink> event for details.
2912         Only frames corresponding to non-native Java programming language
2913         methods can receive notification.
2914         <p/>
2915         The specified thread must be suspended or must be the current thread.
2916       </description>
2917       <origin>jvmdi</origin>
2918       <capabilities>
2919         <required id="can_generate_frame_pop_events"></required>
2920       </capabilities>
2921       <parameters>
2922         <param id="thread">
2923           <jthread null="current" frame="depth"/>
2924           <description>
2925             The thread of the frame for which the frame pop event will be generated.
2926           </description>
2927         </param>
2928         <param id="depth">
2929           <jframeID thread="thread"/>
2930           <description>
2931             The depth of the frame for which the frame pop event will be generated.
2932           </description>
2933         </param>
2934       </parameters>
2935       <errors>
2936         <error id="JVMTI_ERROR_OPAQUE_FRAME">
2937           The frame at <code>depth</code> is executing a
2938           native method.
2939         </error>
2940         <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
2941           Thread was not suspended and was not the current thread.
2942         </error>
2943       </errors>
2944     </function>
2945 
2946   </category>
2947 
2948   <category id="ForceEarlyReturn" label="Force Early Return">
2949     <intro>
2950       These functions allow an agent to force a method
2951       to return at any point during its execution.
2952       The method which will return early is referred to as the <i>called method</i>.
2953       The called method is the current method
2954       (as defined by
2955       <vmspec chapter="3.6"/>)
2956       for the specified thread at
2957       the time the function is called.
2958       <p/>
2959       The specified thread must be suspended or must be the current thread.
2960       The return occurs when execution of Java programming
2961       language code is resumed on this thread.
2962       Between calling one of these functions and resumption
2963       of thread execution, the state of the stack is undefined.
2964       <p/>
2965       No further instructions are executed in the called method.
2966       Specifically, finally blocks are not executed.
2967       Note: this can cause inconsistent states in the application.
2968       <p/>
2969       A lock acquired by calling the called method
2970       (if it is a <code>synchronized</code>  method)
2971       and locks acquired by entering <code>synchronized</code>
2972       blocks within the called method are released.
2973       Note: this does not apply to native locks or
2974       <code>java.util.concurrent.locks</code> locks.
2975       <p/>
2976       Events, such as <eventlink id="MethodExit"></eventlink>,
2977       are generated as they would be in a normal return.
2978       <p/>
2979       The called method must be a non-native Java programming
2980       language method.
2981       Forcing return on a thread with only one frame on the
2982       stack causes the thread to exit when resumed.
2983     </intro>
2984 
2985     <function id="ForceEarlyReturnObject" num="81" since="1.1">
2986       <synopsis>Force Early Return - Object</synopsis>
2987       <description>
2988         This function can be used to return from a method whose
2989         result type is <code>Object</code>
2990         or a subclass of <code>Object</code>.
2991       </description>
2992       <origin>new</origin>
2993       <capabilities>
2994         <required id="can_force_early_return"></required>
2995       </capabilities>
2996       <parameters>
2997         <param id="thread">
2998           <jthread null="current"/>
2999           <description>
3000             The thread whose current frame is to return early.
3001           </description>
3002         </param>
3003         <param id="value">
3004           <jobject/>
3005           <description>
3006             The return value for the called frame.
3007             An object or <code>NULL</code>.
3008           </description>
3009         </param>
3010       </parameters>
3011       <errors>
3012         <error id="JVMTI_ERROR_OPAQUE_FRAME">
3013           Attempted to return early from a frame
3014           corresponding to a native method.
3015           Or the implementation is unable to provide
3016           this functionality on this frame.
3017         </error>
3018         <error id="JVMTI_ERROR_TYPE_MISMATCH">
3019           The result type of the called method is not
3020           <code>Object</code> or a subclass of <code>Object</code>.
3021         </error>
3022         <error id="JVMTI_ERROR_TYPE_MISMATCH">
3023           The supplied <paramlink id="value"/> is not compatible with the
3024           result type of the called method.
3025         </error>
3026         <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
3027           Thread was not suspended and was not the current thread.
3028         </error>
3029         <error id="JVMTI_ERROR_NO_MORE_FRAMES">
3030           There are no more frames on the call stack.
3031         </error>
3032       </errors>
3033     </function>
3034 
3035     <function id="ForceEarlyReturnInt" num="82" since="1.1">
3036       <synopsis>Force Early Return - Int</synopsis>
3037       <description>
3038         This function can be used to return from a method whose
3039         result type is <code>int</code>, <code>short</code>,
3040         <code>char</code>, <code>byte</code>, or
3041         <code>boolean</code>.
3042       </description>
3043       <origin>new</origin>
3044       <capabilities>
3045         <required id="can_force_early_return"></required>
3046       </capabilities>
3047       <parameters>
3048         <param id="thread">
3049           <jthread null="current"/>
3050           <description>
3051             The thread whose current frame is to return early.
3052           </description>
3053         </param>
3054         <param id="value">
3055           <jint/>
3056           <description>
3057             The return value for the called frame.
3058           </description>
3059         </param>
3060       </parameters>
3061       <errors>
3062         <error id="JVMTI_ERROR_OPAQUE_FRAME">
3063           Attempted to return early from a frame
3064           corresponding to a native method.
3065           Or the implementation is unable to provide
3066           this functionality on this frame.
3067         </error>
3068         <error id="JVMTI_ERROR_TYPE_MISMATCH">
3069           The result type of the called method is not
3070           <code>int</code>, <code>short</code>,
3071           <code>char</code>, <code>byte</code>, or
3072           <code>boolean</code>.
3073         </error>
3074         <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
3075           Thread was not suspended and was not the current thread.
3076         </error>
3077         <error id="JVMTI_ERROR_NO_MORE_FRAMES">
3078           There are no frames on the call stack.
3079         </error>
3080       </errors>
3081     </function>
3082 
3083     <function id="ForceEarlyReturnLong" num="83" since="1.1">
3084       <synopsis>Force Early Return - Long</synopsis>
3085       <description>
3086         This function can be used to return from a method whose
3087         result type is <code>long</code>.
3088       </description>
3089       <origin>new</origin>
3090       <capabilities>
3091         <required id="can_force_early_return"></required>
3092       </capabilities>
3093       <parameters>
3094         <param id="thread">
3095           <jthread null="current"/>
3096           <description>
3097             The thread whose current frame is to return early.
3098           </description>
3099         </param>
3100         <param id="value">
3101           <jlong/>
3102           <description>
3103             The return value for the called frame.
3104           </description>
3105         </param>
3106       </parameters>
3107       <errors>
3108         <error id="JVMTI_ERROR_OPAQUE_FRAME">
3109           Attempted to return early from a frame
3110           corresponding to a native method.
3111           Or the implementation is unable to provide
3112           this functionality on this frame.
3113         </error>
3114         <error id="JVMTI_ERROR_TYPE_MISMATCH">
3115           The result type of the called method is not <code>long</code>.
3116         </error>
3117         <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
3118           Thread was not suspended and was not the current thread.
3119         </error>
3120         <error id="JVMTI_ERROR_NO_MORE_FRAMES">
3121           There are no frames on the call stack.
3122         </error>
3123       </errors>
3124     </function>
3125 
3126     <function id="ForceEarlyReturnFloat" num="84" since="1.1">
3127       <synopsis>Force Early Return - Float</synopsis>
3128       <description>
3129         This function can be used to return from a method whose
3130         result type is <code>float</code>.
3131       </description>
3132       <origin>new</origin>
3133       <capabilities>
3134         <required id="can_force_early_return"></required>
3135       </capabilities>
3136       <parameters>
3137         <param id="thread">
3138           <jthread null="current"/>
3139           <description>
3140             The thread whose current frame is to return early.
3141           </description>
3142         </param>
3143         <param id="value">
3144           <jfloat/>
3145           <description>
3146             The return value for the called frame.
3147           </description>
3148         </param>
3149       </parameters>
3150       <errors>
3151         <error id="JVMTI_ERROR_OPAQUE_FRAME">
3152           Attempted to return early from a frame
3153           corresponding to a native method.
3154           Or the implementation is unable to provide
3155           this functionality on this frame.
3156         </error>
3157         <error id="JVMTI_ERROR_TYPE_MISMATCH">
3158           The result type of the called method is not <code>float</code>.
3159         </error>
3160         <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
3161           Thread was not suspended and was not the current thread.
3162         </error>
3163         <error id="JVMTI_ERROR_NO_MORE_FRAMES">
3164           There are no frames on the call stack.
3165         </error>
3166       </errors>
3167     </function>
3168 
3169     <function id="ForceEarlyReturnDouble" num="85" since="1.1">
3170       <synopsis>Force Early Return - Double</synopsis>
3171       <description>
3172         This function can be used to return from a method whose
3173         result type is <code>double</code>.
3174       </description>
3175       <origin>new</origin>
3176       <capabilities>
3177         <required id="can_force_early_return"></required>
3178       </capabilities>
3179       <parameters>
3180         <param id="thread">
3181           <jthread null="current"/>
3182           <description>
3183             The thread whose current frame is to return early.
3184           </description>
3185         </param>
3186         <param id="value">
3187           <jdouble/>
3188           <description>
3189             The return value for the called frame.
3190           </description>
3191         </param>
3192       </parameters>
3193       <errors>
3194         <error id="JVMTI_ERROR_OPAQUE_FRAME">
3195           Attempted to return early from a frame corresponding to a native method.
3196           Or the implementation is unable to provide this functionality on this frame.
3197         </error>
3198         <error id="JVMTI_ERROR_TYPE_MISMATCH">
3199           The result type of the called method is not <code>double</code>.
3200         </error>
3201         <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
3202           Thread was not suspended and was not the current thread.
3203         </error>
3204         <error id="JVMTI_ERROR_NO_MORE_FRAMES">
3205           There are no frames on the call stack.
3206         </error>
3207       </errors>
3208     </function>
3209 
3210     <function id="ForceEarlyReturnVoid" num="86" since="1.1">
3211       <synopsis>Force Early Return - Void</synopsis>
3212       <description>
3213         This function can be used to return from a method with no result type.
3214         That is, the called method must be declared <code>void</code>.
3215       </description>
3216       <origin>new</origin>
3217       <capabilities>
3218         <required id="can_force_early_return"></required>
3219       </capabilities>
3220       <parameters>
3221         <param id="thread">
3222           <jthread null="current"/>
3223           <description>
3224             The thread whose current frame is to return early.
3225           </description>
3226         </param>
3227       </parameters>
3228       <errors>
3229         <error id="JVMTI_ERROR_OPAQUE_FRAME">
3230           Attempted to return early from a frame
3231           corresponding to a native method.
3232           Or the implementation is unable to provide
3233           this functionality on this frame.
3234         </error>
3235         <error id="JVMTI_ERROR_TYPE_MISMATCH">
3236           The called method has a result type.
3237         </error>
3238         <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
3239           Thread was not suspended and was not the current thread.
3240         </error>
3241         <error id="JVMTI_ERROR_NO_MORE_FRAMES">
3242           There are no frames on the call stack.
3243         </error>
3244       </errors>
3245     </function>
3246 
3247   </category>
3248 
3249   <category id="Heap" label="Heap">
3250     <intro>
3251       These functions are used to analyze the heap.
3252       Functionality includes the ability to view the objects in the
3253       heap and to tag these objects.
3254     </intro>
3255 
3256     <intro id="objectTags" label="Object Tags">
3257       A <i>tag</i> is a value associated with an object.
3258       Tags are explicitly set by the agent using the
3259       <functionlink id="SetTag"></functionlink> function or by
3260       callback functions such as <functionlink id="jvmtiHeapIterationCallback"/>.
3261       <p/>
3262       Tags are local to the environment; that is, the tags of one
3263       environment are not visible in another.
3264       <p/>
3265       Tags are <code>jlong</code> values which can be used
3266       simply to mark an object or to store a pointer to more detailed
3267       information.  Objects which have not been tagged have a
3268       tag of zero.
3269       Setting a tag to zero makes the object untagged.
3270     </intro>
3271 
3272     <intro id="heapCallbacks" label="Heap Callback Functions">
3273         Heap functions which iterate through the heap and recursively
3274         follow object references use agent supplied callback functions
3275         to deliver the information.
3276         <p/>
3277         These heap callback functions must adhere to the following restrictions --
3278         These callbacks must not use JNI functions.
3279         These callbacks must not use <jvmti/> functions except
3280         <i>callback safe</i> functions which
3281         specifically allow such use (see the raw monitor, memory management,
3282         and environment local storage functions).
3283         <p/>
3284         An implementation may invoke a callback on an internal thread or
3285         the thread which called the iteration function.
3286         Heap callbacks are single threaded -- no more than one callback will
3287         be invoked at a time.
3288         <p/>
3289         The Heap Filter Flags can be used to prevent reporting
3290         based on the tag status of an object or its class.
3291         If no flags are set (the <code>jint</code> is zero), objects
3292         will not be filtered out.
3293 
3294         <constants id="jvmtiHeapFilter" label="Heap Filter Flags" kind="bits">
3295           <constant id="JVMTI_HEAP_FILTER_TAGGED" num="0x4">
3296             Filter out tagged objects. Objects which are tagged are not included.
3297           </constant>
3298           <constant id="JVMTI_HEAP_FILTER_UNTAGGED" num="0x8">
3299             Filter out untagged objects. Objects which are not tagged are not included.
3300           </constant>
3301           <constant id="JVMTI_HEAP_FILTER_CLASS_TAGGED" num="0x10">
3302             Filter out objects with tagged classes. Objects whose class is tagged are not included.
3303           </constant>
3304           <constant id="JVMTI_HEAP_FILTER_CLASS_UNTAGGED" num="0x20">
3305             Filter out objects with untagged classes. Objects whose class is not tagged are not included.
3306           </constant>
3307         </constants>
3308 
3309         <p/>
3310         The Heap Visit Control Flags are returned by the heap callbacks
3311         and can be used to abort the iteration.  For the
3312         <functionlink id="jvmtiHeapReferenceCallback">Heap
3313         Reference Callback</functionlink>, it can also be used
3314         to prune the graph of traversed references
3315         (<code>JVMTI_VISIT_OBJECTS</code> is not set).
3316 
3317         <constants id="jvmtiHeapVisitControl"
3318                    label="Heap Visit Control Flags"
3319                    kind="bits"
3320                    since="1.1">
3321           <constant id="JVMTI_VISIT_OBJECTS" num="0x100">
3322             If we are visiting an object and if this callback
3323             was initiated by <functionlink id="FollowReferences"/>,
3324             traverse the references of this object.
3325             Otherwise ignored.
3326           </constant>
3327           <constant id="JVMTI_VISIT_ABORT" num="0x8000">
3328             Abort the iteration.  Ignore all other bits.
3329           </constant>
3330         </constants>
3331 
3332         <p/>
3333         The Heap Reference Enumeration is provided by the
3334         <functionlink id="jvmtiHeapReferenceCallback">Heap
3335         Reference Callback</functionlink> and
3336         <functionlink id="jvmtiPrimitiveFieldCallback">Primitive Field
3337         Callback</functionlink> to
3338         describe the kind of reference
3339         being reported.
3340 
3341         <constants id="jvmtiHeapReferenceKind"
3342                    label="Heap Reference Enumeration"
3343                    kind="enum"
3344                    since="1.1">
3345           <constant id="JVMTI_HEAP_REFERENCE_CLASS" num="1">
3346             Reference from an object to its class.
3347           </constant>
3348           <constant id="JVMTI_HEAP_REFERENCE_FIELD" num="2">
3349             Reference from an object to the value of one of its instance fields.
3350           </constant>
3351           <constant id="JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT" num="3">
3352             Reference from an array to one of its elements.
3353           </constant>
3354           <constant id="JVMTI_HEAP_REFERENCE_CLASS_LOADER" num="4">
3355             Reference from a class to its class loader.
3356           </constant>
3357           <constant id="JVMTI_HEAP_REFERENCE_SIGNERS" num="5">
3358             Reference from a class to its signers array.
3359           </constant>
3360           <constant id="JVMTI_HEAP_REFERENCE_PROTECTION_DOMAIN" num="6">
3361             Reference from a class to its protection domain.
3362           </constant>
3363           <constant id="JVMTI_HEAP_REFERENCE_INTERFACE" num="7">
3364             Reference from a class to one of its interfaces.
3365             Note: interfaces are defined via a constant pool reference,
3366             so the referenced interfaces may also be reported with a
3367             <code>JVMTI_HEAP_REFERENCE_CONSTANT_POOL</code> reference kind.
3368           </constant>
3369           <constant id="JVMTI_HEAP_REFERENCE_STATIC_FIELD" num="8">
3370             Reference from a class to the value of one of its static fields.
3371           </constant>
3372           <constant id="JVMTI_HEAP_REFERENCE_CONSTANT_POOL" num="9">
3373             Reference from a class to a resolved entry in the constant pool.
3374           </constant>
3375           <constant id="JVMTI_HEAP_REFERENCE_SUPERCLASS" num="10">
3376             Reference from a class to its superclass.
3377             A callback is not sent if the superclass is <code>java.lang.Object</code>.
3378             Note: loaded classes define superclasses via a constant pool
3379             reference, so the referenced superclass may also be reported with
3380             a <code>JVMTI_HEAP_REFERENCE_CONSTANT_POOL</code> reference kind.
3381           </constant>
3382           <constant id="JVMTI_HEAP_REFERENCE_JNI_GLOBAL" num="21">
3383             Heap root reference: JNI global reference.
3384           </constant>
3385           <constant id="JVMTI_HEAP_REFERENCE_SYSTEM_CLASS" num="22">
3386             Heap root reference: System class.
3387           </constant>
3388           <constant id="JVMTI_HEAP_REFERENCE_MONITOR" num="23">
3389             Heap root reference: monitor.
3390           </constant>
3391           <constant id="JVMTI_HEAP_REFERENCE_STACK_LOCAL" num="24">
3392             Heap root reference: local variable on the stack.
3393           </constant>
3394           <constant id="JVMTI_HEAP_REFERENCE_JNI_LOCAL" num="25">
3395             Heap root reference: JNI local reference.
3396           </constant>
3397           <constant id="JVMTI_HEAP_REFERENCE_THREAD" num="26">
3398             Heap root reference: Thread.
3399           </constant>
3400           <constant id="JVMTI_HEAP_REFERENCE_OTHER" num="27">
3401             Heap root reference: other heap root reference.
3402           </constant>
3403         </constants>
3404 
3405         <p/>
3406         Definitions for the single character type descriptors of
3407         primitive types.
3408 
3409         <constants id="jvmtiPrimitiveType"
3410                    label="Primitive Type Enumeration"
3411                    kind="enum"
3412                    since="1.1">
3413           <constant id="JVMTI_PRIMITIVE_TYPE_BOOLEAN" num="90">
3414             'Z' - Java programming language <code>boolean</code> - JNI <code>jboolean</code>
3415           </constant>
3416           <constant id="JVMTI_PRIMITIVE_TYPE_BYTE" num="66">
3417             'B' - Java programming language <code>byte</code> - JNI <code>jbyte</code>
3418           </constant>
3419           <constant id="JVMTI_PRIMITIVE_TYPE_CHAR" num="67">
3420             'C' - Java programming language <code>char</code> - JNI <code>jchar</code>
3421           </constant>
3422           <constant id="JVMTI_PRIMITIVE_TYPE_SHORT" num="83">
3423             'S' - Java programming language <code>short</code> - JNI <code>jshort</code>
3424           </constant>
3425           <constant id="JVMTI_PRIMITIVE_TYPE_INT" num="73">
3426             'I' - Java programming language <code>int</code> - JNI <code>jint</code>
3427           </constant>
3428           <constant id="JVMTI_PRIMITIVE_TYPE_LONG" num="74">
3429             'J' - Java programming language <code>long</code> - JNI <code>jlong</code>
3430           </constant>
3431           <constant id="JVMTI_PRIMITIVE_TYPE_FLOAT" num="70">
3432             'F' - Java programming language <code>float</code> - JNI <code>jfloat</code>
3433           </constant>
3434           <constant id="JVMTI_PRIMITIVE_TYPE_DOUBLE" num="68">
3435             'D' - Java programming language <code>double</code> - JNI <code>jdouble</code>
3436           </constant>
3437         </constants>
3438     </intro>
3439 
3440       <typedef id="jvmtiHeapReferenceInfoField"
3441                label="Reference information structure for Field references"
3442                since="1.1">
3443         <description>
3444           Reference information returned for
3445           <datalink id="JVMTI_HEAP_REFERENCE_FIELD"/> and
3446           <datalink id="JVMTI_HEAP_REFERENCE_STATIC_FIELD"/> references.
3447         </description>
3448         <field id="index">
3449           <jint/>
3450           <description>
3451             For <datalink id="JVMTI_HEAP_REFERENCE_FIELD"/>, the
3452             referrer object is not a class or an interface.
3453             In this case, <code>index</code> is the index of the field
3454             in the class of the referrer object.
3455             This class is referred to below as <i>C</i>.
3456             <p/>
3457             For <datalink id="JVMTI_HEAP_REFERENCE_STATIC_FIELD"/>,
3458             the referrer object is a class (referred to below as <i>C</i>)
3459             or an interface (referred to below as <i>I</i>).
3460             In this case, <code>index</code> is the index of the field in
3461             that class or interface.
3462             <p/>
3463             If the referrer object is not an interface, then the field
3464             indices are determined as follows:
3465             <ul>
3466               <li>make a list of all the fields in <i>C</i> and its
3467                   superclasses, starting with all the fields in
3468                   <code>java.lang.Object</code> and ending with all the
3469                   fields in <i>C</i>.</li>
3470               <li>Within this list, put
3471                   the fields for a given class in the order returned by
3472                   <functionlink id="GetClassFields"/>.</li>
3473               <li>Assign the fields in this list indices
3474                   <i>n</i>, <i>n</i>+1, ..., in order, where <i>n</i>
3475                   is the count of the fields in all the interfaces
3476                   implemented by <i>C</i>.
3477                   Note that <i>C</i> implements all interfaces
3478                   directly implemented by its superclasses; as well
3479                   as all superinterfaces of these interfaces.</li>
3480             </ul>
3481             If the referrer object is an interface, then the field
3482             indices are determined as follows:
3483             <ul>
3484               <li>make a list of the fields directly declared in
3485                   <i>I</i>.</li>
3486               <li>Within this list, put
3487                   the fields in the order returned by
3488                   <functionlink id="GetClassFields"/>.</li>
3489               <li>Assign the fields in this list indices
3490                   <i>n</i>, <i>n</i>+1, ..., in order, where <i>n</i>
3491                   is the count of the fields in all the superinterfaces
3492                   of <i>I</i>.</li>
3493             </ul>
3494             All fields are included in this computation, regardless of
3495             field modifier (static, public, private, etc).
3496             <p/>
3497             For example, given the following classes and interfaces:
3498             <example>
3499 interface I0 {
3500     int p = 0;
3501 }
3502 
3503 interface I1 extends I0 {
3504     int x = 1;
3505 }
3506 
3507 interface I2 extends I0 {
3508     int y = 2;
3509 }
3510 
3511 class C1 implements I1 {
3512     public static int a = 3;
3513     private int b = 4;
3514 }
3515 
3516 class C2 extends C1 implements I2 {
3517     static int q = 5;
3518     final int r = 6;
3519 }
3520             </example>
3521             Assume that <functionlink id="GetClassFields"/> called on
3522             <code>C1</code> returns the fields of <code>C1</code> in the
3523             order: a, b; and that the fields of <code>C2</code> are
3524             returned in the order: q, r.
3525             An instance of class <code>C1</code> will have the
3526             following field indices:
3527             <blockquote><table>
3528               <tr class="bgLight">
3529                 <th class="centered" scope="col">Field</th>
3530                 <th class="centered" scope="col">Index</th>
3531                 <th scope="col">Description</th>
3532               </tr>
3533               <tr>
3534                 <th class="centered" scope="row">
3535                   a
3536                 </th>
3537                 <td class="centered">
3538                   2
3539                 </td>
3540                 <td>
3541                   The count of the fields in the interfaces
3542                   implemented by <code>C1</code> is two (<i>n</i>=2):
3543                   <code>p</code> of <code>I0</code>
3544                   and <code>x</code> of <code>I1</code>.
3545                 </td>
3546               </tr>
3547               <tr>
3548                 <th class="centered" scope="row">
3549                   b
3550                 </th>
3551                 <td class="centered">
3552                   3
3553                 </td>
3554                 <td>
3555                   the subsequent index.
3556                 </td>
3557               </tr>
3558             </table></blockquote>
3559             The class <code>C1</code> will have the same field indices.
3560             <p/>
3561             An instance of class <code>C2</code> will have the
3562             following field indices:
3563             <blockquote><table>
3564               <tr class="bgLight">
3565                 <th class="centered" scope="col">Field</th>
3566                 <th class="centered" scope="col">Index</th>
3567                 <th scope="col">Description</th>
3568               </tr>
3569               <tr>
3570                 <th class="centered" scope="row">
3571                   a
3572                 </th>
3573                 <td class="centered">
3574                   3
3575                 </td>
3576                 <td>
3577                   The count of the fields in the interfaces
3578                   implemented by <code>C2</code> is three (<i>n</i>=3):
3579                   <code>p</code> of <code>I0</code>,
3580                   <code>x</code> of <code>I1</code> and <code>y</code> of <code>I2</code>
3581                   (an interface of <code>C2</code>).  Note that the field <code>p</code>
3582                   of <code>I0</code> is only included once.
3583                 </td>
3584               </tr>
3585               <tr>
3586                 <th class="centered" scope="row">
3587                   b
3588                 </th>
3589                 <td class="centered">
3590                   4
3591                 </td>
3592                 <td>
3593                   the subsequent index to "a".
3594                 </td>
3595               </tr>
3596               <tr>
3597                 <th class="centered" scope="row">
3598                   q
3599                 </th>
3600                 <td class="centered">
3601                   5
3602                 </td>
3603                 <td>
3604                   the subsequent index to "b".
3605                 </td>
3606               </tr>
3607               <tr>
3608                 <th class="centered" scope="row">
3609                   r
3610                 </th>
3611                 <td class="centered">
3612                   6
3613                 </td>
3614                 <td>
3615                   the subsequent index to "q".
3616                 </td>
3617               </tr>
3618             </table></blockquote>
3619             The class <code>C2</code> will have the same field indices.
3620             Note that a field may have a different index depending on the
3621             object that is viewing it -- for example field "a" above.
3622             Note also: not all field indices may be visible from the
3623             callbacks, but all indices are shown for illustrative purposes.
3624             <p/>
3625             The interface <code>I1</code> will have the
3626             following field indices:
3627             <blockquote><table>
3628               <tr class="bgLight">
3629                 <th class="centered" scope="col">Field</th>
3630                 <th class="centered" scope="col">Index</th>
3631                 <th scope="col">Description</th>
3632               </tr>
3633               <tr>
3634                 <th class="centered" scope="row">
3635                   x
3636                 </th>
3637                 <td class="centered">
3638                   1
3639                 </td>
3640                 <td>
3641                   The count of the fields in the superinterfaces
3642                   of <code>I1</code> is one (<i>n</i>=1):
3643                   <code>p</code> of <code>I0</code>.
3644                 </td>
3645               </tr>
3646             </table></blockquote>
3647           </description>
3648         </field>
3649       </typedef>
3650 
3651       <typedef id="jvmtiHeapReferenceInfoArray"
3652                label="Reference information structure for Array references"
3653                since="1.1">
3654         <description>
3655           Reference information returned for
3656          <datalink id="JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT"/> references.
3657         </description>
3658         <field id="index">
3659           <jint/>
3660           <description>
3661             The array index.
3662           </description>
3663         </field>
3664       </typedef>
3665 
3666       <typedef id="jvmtiHeapReferenceInfoConstantPool"
3667                label="Reference information structure for Constant Pool references"
3668                since="1.1">
3669         <description>
3670           Reference information returned for
3671           <datalink id="JVMTI_HEAP_REFERENCE_CONSTANT_POOL"/> references.
3672         </description>
3673         <field id="index">
3674           <jint/>
3675           <description>
3676             The index into the constant pool of the class. See the description in
3677       <vmspec chapter="4.4"/>.
3678           </description>
3679         </field>
3680       </typedef>
3681 
3682       <typedef id="jvmtiHeapReferenceInfoStackLocal"
3683                label="Reference information structure for Local Variable references"
3684                since="1.1">
3685         <description>
3686           Reference information returned for
3687           <datalink id="JVMTI_HEAP_REFERENCE_STACK_LOCAL"/> references.
3688         </description>
3689         <field id="thread_tag">
3690           <jlong/>
3691           <description>
3692             The tag of the thread corresponding to this stack, zero if not tagged.
3693           </description>
3694         </field>
3695         <field id="thread_id">
3696           <jlong/>
3697           <description>
3698             The unique thread ID of the thread corresponding to this stack.
3699           </description>
3700         </field>
3701         <field id="depth">
3702           <jint/>
3703           <description>
3704             The depth of the frame.
3705           </description>
3706         </field>
3707         <field id="method">
3708           <jmethodID/>
3709           <description>
3710             The method executing in this frame.
3711           </description>
3712         </field>
3713         <field id="location">
3714           <jlocation/>
3715           <description>
3716             The currently executing location in this frame.
3717           </description>
3718         </field>
3719         <field id="slot">
3720           <jint/>
3721           <description>
3722             The slot number of the local variable.
3723           </description>
3724         </field>
3725       </typedef>
3726 
3727       <typedef id="jvmtiHeapReferenceInfoJniLocal"
3728                label="Reference information structure for JNI local references"
3729                since="1.1">
3730         <description>
3731           Reference information returned for
3732           <datalink id="JVMTI_HEAP_REFERENCE_JNI_LOCAL"/> references.
3733         </description>
3734         <field id="thread_tag">
3735           <jlong/>
3736           <description>
3737             The tag of the thread corresponding to this stack, zero if not tagged.
3738           </description>
3739         </field>
3740         <field id="thread_id">
3741           <jlong/>
3742           <description>
3743             The unique thread ID of the thread corresponding to this stack.
3744           </description>
3745         </field>
3746         <field id="depth">
3747           <jint/>
3748           <description>
3749             The depth of the frame.
3750           </description>
3751         </field>
3752         <field id="method">
3753           <jmethodID/>
3754           <description>
3755             The method executing in this frame.
3756           </description>
3757         </field>
3758       </typedef>
3759 
3760       <typedef id="jvmtiHeapReferenceInfoReserved"
3761                label="Reference information structure for Other references"
3762                since="1.1">
3763         <description>
3764           Reference information returned for other references.
3765         </description>
3766         <field id="reserved1">
3767           <jlong/>
3768           <description>
3769             reserved for future use.
3770           </description>
3771         </field>
3772         <field id="reserved2">
3773           <jlong/>
3774           <description>
3775             reserved for future use.
3776           </description>
3777         </field>
3778         <field id="reserved3">
3779           <jlong/>
3780           <description>
3781             reserved for future use.
3782           </description>
3783         </field>
3784         <field id="reserved4">
3785           <jlong/>
3786           <description>
3787             reserved for future use.
3788           </description>
3789         </field>
3790         <field id="reserved5">
3791           <jlong/>
3792           <description>
3793             reserved for future use.
3794           </description>
3795         </field>
3796         <field id="reserved6">
3797           <jlong/>
3798           <description>
3799             reserved for future use.
3800           </description>
3801         </field>
3802         <field id="reserved7">
3803           <jlong/>
3804           <description>
3805             reserved for future use.
3806           </description>
3807         </field>
3808         <field id="reserved8">
3809           <jlong/>
3810           <description>
3811             reserved for future use.
3812           </description>
3813         </field>
3814       </typedef>
3815 
3816       <uniontypedef id="jvmtiHeapReferenceInfo"
3817                label="Reference information structure"
3818                since="1.1">
3819         <description>
3820           The information returned about referrers.
3821           Represented as a union of the various kinds of reference information.
3822         </description>
3823         <field id="field">
3824           <struct>jvmtiHeapReferenceInfoField</struct>
3825           <description>
3826             The referrer information for
3827             <datalink id="JVMTI_HEAP_REFERENCE_FIELD"/>
3828             and <datalink id="JVMTI_HEAP_REFERENCE_STATIC_FIELD"/> references.
3829           </description>
3830         </field>
3831         <field id="array">
3832           <struct>jvmtiHeapReferenceInfoArray</struct>
3833           <description>
3834             The referrer information for
3835             For <datalink id="JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT"/> references.
3836           </description>
3837         </field>
3838         <field id="constant_pool">
3839           <struct>jvmtiHeapReferenceInfoConstantPool</struct>
3840           <description>
3841             The referrer information for
3842             For <datalink id="JVMTI_HEAP_REFERENCE_CONSTANT_POOL"/> references.
3843           </description>
3844         </field>
3845         <field id="stack_local">
3846           <struct>jvmtiHeapReferenceInfoStackLocal</struct>
3847           <description>
3848             The referrer information for
3849             For <datalink id="JVMTI_HEAP_REFERENCE_STACK_LOCAL"/> references.
3850           </description>
3851         </field>
3852         <field id="jni_local">
3853           <struct>jvmtiHeapReferenceInfoJniLocal</struct>
3854           <description>
3855             The referrer information for
3856             For <datalink id="JVMTI_HEAP_REFERENCE_JNI_LOCAL"/> references.
3857           </description>
3858         </field>
3859         <field id="other">
3860           <struct>jvmtiHeapReferenceInfoReserved</struct>
3861           <description>
3862             reserved for future use.
3863           </description>
3864         </field>
3865       </uniontypedef>
3866 
3867       <typedef id="jvmtiHeapCallbacks"
3868                label="Heap callback function structure"
3869                since="1.1">
3870         <field id="heap_iteration_callback">
3871           <ptrtype>
3872             <struct>jvmtiHeapIterationCallback</struct>
3873           </ptrtype>
3874           <description>
3875             The callback to be called to describe an
3876             object in the heap. Used by the
3877             <functionlink id="IterateThroughHeap"/> function, ignored by the
3878             <functionlink id="FollowReferences"/> function.
3879           </description>
3880         </field>
3881         <field id="heap_reference_callback">
3882           <ptrtype>
3883             <struct>jvmtiHeapReferenceCallback</struct>
3884           </ptrtype>
3885           <description>
3886             The callback to be called to describe an
3887             object reference.  Used by the
3888             <functionlink id="FollowReferences"/> function, ignored by the
3889             <functionlink id="IterateThroughHeap"/> function.
3890           </description>
3891         </field>
3892         <field id="primitive_field_callback">
3893           <ptrtype>
3894             <struct>jvmtiPrimitiveFieldCallback</struct>
3895           </ptrtype>
3896           <description>
3897             The callback to be called to describe a
3898             primitive field.
3899           </description>
3900         </field>
3901         <field id="array_primitive_value_callback">
3902           <ptrtype>
3903             <struct>jvmtiArrayPrimitiveValueCallback</struct>
3904           </ptrtype>
3905           <description>
3906             The callback to be called to describe an
3907             array of primitive values.
3908           </description>
3909         </field>
3910         <field id="string_primitive_value_callback">
3911           <ptrtype>
3912             <struct>jvmtiStringPrimitiveValueCallback</struct>
3913           </ptrtype>
3914           <description>
3915             The callback to be called to describe a String value.
3916           </description>
3917         </field>
3918         <field id="reserved5">
3919           <ptrtype>
3920             <struct>jvmtiReservedCallback</struct>
3921           </ptrtype>
3922           <description>
3923             Reserved for future use..
3924           </description>
3925         </field>
3926         <field id="reserved6">
3927           <ptrtype>
3928             <struct>jvmtiReservedCallback</struct>
3929           </ptrtype>
3930           <description>
3931             Reserved for future use..
3932           </description>
3933         </field>
3934         <field id="reserved7">
3935           <ptrtype>
3936             <struct>jvmtiReservedCallback</struct>
3937           </ptrtype>
3938           <description>
3939             Reserved for future use..
3940           </description>
3941         </field>
3942         <field id="reserved8">
3943           <ptrtype>
3944             <struct>jvmtiReservedCallback</struct>
3945           </ptrtype>
3946           <description>
3947             Reserved for future use..
3948           </description>
3949         </field>
3950         <field id="reserved9">
3951           <ptrtype>
3952             <struct>jvmtiReservedCallback</struct>
3953           </ptrtype>
3954           <description>
3955             Reserved for future use..
3956           </description>
3957         </field>
3958         <field id="reserved10">
3959           <ptrtype>
3960             <struct>jvmtiReservedCallback</struct>
3961           </ptrtype>
3962           <description>
3963             Reserved for future use..
3964           </description>
3965         </field>
3966         <field id="reserved11">
3967           <ptrtype>
3968             <struct>jvmtiReservedCallback</struct>
3969           </ptrtype>
3970           <description>
3971             Reserved for future use..
3972           </description>
3973         </field>
3974         <field id="reserved12">
3975           <ptrtype>
3976             <struct>jvmtiReservedCallback</struct>
3977           </ptrtype>
3978           <description>
3979             Reserved for future use..
3980           </description>
3981         </field>
3982         <field id="reserved13">
3983           <ptrtype>
3984             <struct>jvmtiReservedCallback</struct>
3985           </ptrtype>
3986           <description>
3987             Reserved for future use..
3988           </description>
3989         </field>
3990         <field id="reserved14">
3991           <ptrtype>
3992             <struct>jvmtiReservedCallback</struct>
3993           </ptrtype>
3994           <description>
3995             Reserved for future use..
3996           </description>
3997         </field>
3998         <field id="reserved15">
3999           <ptrtype>
4000             <struct>jvmtiReservedCallback</struct>
4001           </ptrtype>
4002           <description>
4003             Reserved for future use..
4004           </description>
4005         </field>
4006       </typedef>
4007 
4008 
4009     <intro>
4010       <rationale>
4011         The heap dumping functionality (below) uses a callback
4012         for each object.  While it would seem that a buffered approach
4013         would provide better throughput, tests do
4014         not show this to be the case--possibly due to locality of
4015         memory reference or array access overhead.
4016       </rationale>
4017 
4018       <issue>
4019         Still under investigation as to if java.lang.ref references
4020         are reported as a different type of reference.
4021       </issue>
4022 
4023       <issue>
4024         Should or can an indication of the cost or relative cost of
4025         these operations be included?
4026       </issue>
4027 
4028     </intro>
4029 
4030     <callback id="jvmtiHeapIterationCallback" since="1.1">
4031       <jint/>
4032       <synopsis>Heap Iteration Callback</synopsis>
4033       <description>
4034         Agent supplied callback function.
4035         Describes (but does not pass in) an object in the heap.
4036         <p/>
4037         This function should return a bit vector of the desired
4038         <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>.
4039         This will determine if the entire iteration should be aborted
4040         (the <code>JVMTI_VISIT_OBJECTS</code> flag is ignored).
4041         <p/>
4042         See the <internallink id="heapCallbacks">heap callback
4043         function restrictions</internallink>.
4044       </description>
4045       <parameters>
4046         <param id="class_tag">
4047           <jlong/>
4048           <description>
4049             The tag of the class of object (zero if the class is not tagged).
4050             If the object represents a runtime class,
4051             the <code>class_tag</code> is the tag
4052             associated with <code>java.lang.Class</code>
4053             (zero if <code>java.lang.Class</code> is not tagged).
4054           </description>
4055         </param>
4056         <param id="size">
4057           <jlong/>
4058           <description>
4059             Size of the object (in bytes). See <functionlink id="GetObjectSize"/>.
4060           </description>
4061         </param>
4062         <param id="tag_ptr">
4063           <outptr><jlong/></outptr>
4064           <description>
4065             The object tag value, or zero if the object is not tagged.
4066             To set the tag value to be associated with the object
4067             the agent sets the <code>jlong</code> pointed to by the parameter.
4068           </description>
4069         </param>
4070         <param id="length">
4071           <jint/>
4072           <description>
4073             If this object is an array, the length of the array. Otherwise negative one (-1).
4074           </description>
4075         </param>
4076         <param id="user_data">
4077           <outptr><void/></outptr>
4078           <description>
4079             The user supplied data that was passed into the iteration function.
4080           </description>
4081         </param>
4082       </parameters>
4083     </callback>
4084 
4085     <callback id="jvmtiHeapReferenceCallback" since="1.1">
4086       <jint/>
4087       <synopsis>Heap Reference Callback</synopsis>
4088       <description>
4089         Agent supplied callback function.
4090         Describes a reference from an object or the VM (the referrer) to another object
4091         (the referree) or a heap root to a referree.
4092         <p/>
4093         This function should return a bit vector of the desired
4094         <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>.
4095         This will determine if the objects referenced by the referree
4096         should be visited or if the entire iteration should be aborted.
4097         <p/>
4098         See the <internallink id="heapCallbacks">heap callback
4099         function restrictions</internallink>.
4100       </description>
4101       <parameters>
4102         <param id="reference_kind">
4103           <enum>jvmtiHeapReferenceKind</enum>
4104           <description>
4105             The kind of reference.
4106           </description>
4107         </param>
4108         <param id="reference_info">
4109           <inptr>
4110             <struct>jvmtiHeapReferenceInfo</struct>
4111           </inptr>
4112           <description>
4113             Details about the reference.
4114             Set when the <datalink id="jvmtiHeapReferenceCallback.reference_kind">reference_kind</datalink> is
4115             <datalink id="JVMTI_HEAP_REFERENCE_FIELD"/>,
4116             <datalink id="JVMTI_HEAP_REFERENCE_STATIC_FIELD"/>,
4117             <datalink id="JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT"/>,
4118             <datalink id="JVMTI_HEAP_REFERENCE_CONSTANT_POOL"/>,
4119             <datalink id="JVMTI_HEAP_REFERENCE_STACK_LOCAL"/>,
4120             or <datalink id="JVMTI_HEAP_REFERENCE_JNI_LOCAL"/>.
4121             Otherwise <code>NULL</code>.
4122           </description>
4123         </param>
4124         <param id="class_tag">
4125           <jlong/>
4126           <description>
4127             The tag of the class of referree object (zero if the class is not tagged).
4128             If the referree object represents a runtime class,
4129             the <code>class_tag</code> is the tag
4130             associated with <code>java.lang.Class</code>
4131             (zero if <code>java.lang.Class</code> is not tagged).
4132           </description>
4133         </param>
4134         <param id="referrer_class_tag">
4135           <jlong/>
4136           <description>
4137             The tag of the class of the referrer object (zero if the class is not tagged
4138             or the referree is a heap root). If the referrer object represents a runtime
4139             class, the <code>referrer_class_tag</code> is the tag associated with
4140             the <code>java.lang.Class</code>
4141             (zero if <code>java.lang.Class</code> is not tagged).
4142           </description>
4143         </param>
4144         <param id="size">
4145           <jlong/>
4146           <description>
4147             Size of the referree object (in bytes).
4148             See <functionlink id="GetObjectSize"/>.
4149           </description>
4150         </param>
4151         <param id="tag_ptr">
4152           <outptr><jlong/></outptr>
4153           <description>
4154             Points to the referree object tag value, or zero if the object is not
4155             tagged.
4156             To set the tag value to be associated with the object
4157             the agent sets the <code>jlong</code> pointed to by the parameter.
4158           </description>
4159         </param>
4160         <param id="referrer_tag_ptr">
4161           <outptr><jlong/></outptr>
4162           <description>
4163             Points to the tag of the referrer object, or
4164             points to the zero if the referrer
4165             object is not tagged.
4166             <code>NULL</code> if the referrer in not an object (that is,
4167             this callback is reporting a heap root).
4168             To set the tag value to be associated with the referrer object
4169             the agent sets the <code>jlong</code> pointed to by the parameter.
4170             If this callback is reporting a reference from an object to itself,
4171             <code>referrer_tag_ptr == tag_ptr</code>.
4172           </description>
4173         </param>
4174         <param id="length">
4175           <jint/>
4176           <description>
4177             If this object is an array, the length of the array. Otherwise negative one (-1).
4178           </description>
4179         </param>
4180         <param id="user_data">
4181           <outptr><void/></outptr>
4182           <description>
4183             The user supplied data that was passed into the iteration function.
4184           </description>
4185         </param>
4186       </parameters>
4187     </callback>
4188 
4189     <callback id="jvmtiPrimitiveFieldCallback" since="1.1">
4190       <jint/>
4191       <synopsis>Primitive Field Callback</synopsis>
4192       <description>
4193         Agent supplied callback function which
4194         describes a primitive field of an object (<i>the object</i>).
4195         A primitive field is a field whose type is a primitive type.
4196         This callback will describe a static field if the object is a class,
4197         and otherwise will describe an instance field.
4198         <p/>
4199         This function should return a bit vector of the desired
4200         <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>.
4201         This will determine if the entire iteration should be aborted
4202         (the <code>JVMTI_VISIT_OBJECTS</code> flag is ignored).
4203         <p/>
4204         See the <internallink id="heapCallbacks">heap callback
4205         function restrictions</internallink>.
4206       </description>
4207       <parameters>
4208         <param id="kind">
4209           <enum>jvmtiHeapReferenceKind</enum>
4210           <description>
4211             The kind of field -- instance or static (<datalink id="JVMTI_HEAP_REFERENCE_FIELD"/> or
4212             <datalink id="JVMTI_HEAP_REFERENCE_STATIC_FIELD"/>).
4213           </description>
4214         </param>
4215         <param id="info">
4216           <inptr>
4217             <struct>jvmtiHeapReferenceInfo</struct>
4218           </inptr>
4219           <description>
4220             Which field (the field index).
4221           </description>
4222         </param>
4223         <param id="object_class_tag">
4224           <jlong/>
4225           <description>
4226             The tag of the class of the object (zero if the class is not tagged).
4227             If the object represents a runtime class, the
4228             <code>object_class_tag</code> is the tag
4229             associated with <code>java.lang.Class</code>
4230             (zero if <code>java.lang.Class</code> is not tagged).
4231           </description>
4232         </param>
4233         <param id="object_tag_ptr">
4234           <outptr><jlong/></outptr>
4235           <description>
4236             Points to the tag of the object, or zero if the object is not
4237             tagged.
4238             To set the tag value to be associated with the object
4239             the agent sets the <code>jlong</code> pointed to by the parameter.
4240           </description>
4241         </param>
4242         <param id="value">
4243           <jvalue/>
4244           <description>
4245             The value of the field.
4246           </description>
4247         </param>
4248         <param id="value_type">
4249           <enum>jvmtiPrimitiveType</enum>
4250           <description>
4251             The type of the field.
4252           </description>
4253         </param>
4254         <param id="user_data">
4255           <outptr><void/></outptr>
4256           <description>
4257             The user supplied data that was passed into the iteration function.
4258           </description>
4259         </param>
4260       </parameters>
4261     </callback>
4262 
4263     <callback id="jvmtiArrayPrimitiveValueCallback" since="1.1">
4264       <jint/>
4265       <synopsis>Array Primitive Value Callback</synopsis>
4266       <description>
4267         Agent supplied callback function.
4268         Describes the values in an array of a primitive type.
4269         <p/>
4270         This function should return a bit vector of the desired
4271         <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>.
4272         This will determine if the entire iteration should be aborted
4273         (the <code>JVMTI_VISIT_OBJECTS</code> flag is ignored).
4274         <p/>
4275         See the <internallink id="heapCallbacks">heap callback
4276         function restrictions</internallink>.
4277       </description>
4278       <parameters>
4279         <param id="class_tag">
4280           <jlong/>
4281           <description>
4282             The tag of the class of the array object (zero if the class is not tagged).
4283           </description>
4284         </param>
4285         <param id="size">
4286           <jlong/>
4287           <description>
4288             Size of the array (in bytes).
4289             See <functionlink id="GetObjectSize"/>.
4290           </description>
4291         </param>
4292         <param id="tag_ptr">
4293           <outptr><jlong/></outptr>
4294           <description>
4295             Points to the tag of the array object, or zero if the object is not
4296             tagged.
4297             To set the tag value to be associated with the object
4298             the agent sets the <code>jlong</code> pointed to by the parameter.
4299           </description>
4300         </param>
4301         <param id="element_count">
4302           <jint/>
4303           <description>
4304             The length of the primitive array.
4305           </description>
4306         </param>
4307         <param id="element_type">
4308           <enum>jvmtiPrimitiveType</enum>
4309           <description>
4310             The type of the elements of the array.
4311           </description>
4312         </param>
4313         <param id="elements">
4314           <vmbuf><void/></vmbuf>
4315           <description>
4316             The elements of the array in a packed array of <code>element_count</code>
4317             items of <code>element_type</code> size each.
4318           </description>
4319         </param>
4320         <param id="user_data">
4321           <outptr><void/></outptr>
4322           <description>
4323             The user supplied data that was passed into the iteration function.
4324           </description>
4325         </param>
4326       </parameters>
4327     </callback>
4328 
4329     <callback id="jvmtiStringPrimitiveValueCallback" since="1.1">
4330       <jint/>
4331       <synopsis>String Primitive Value Callback</synopsis>
4332       <description>
4333         Agent supplied callback function.
4334         Describes the value of a java.lang.String.
4335         <p/>
4336         This function should return a bit vector of the desired
4337         <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>.
4338         This will determine if the entire iteration should be aborted
4339         (the <code>JVMTI_VISIT_OBJECTS</code> flag is ignored).
4340         <p/>
4341         See the <internallink id="heapCallbacks">heap callback
4342         function restrictions</internallink>.
4343       </description>
4344       <parameters>
4345         <param id="class_tag">
4346           <jlong/>
4347           <description>
4348             The tag of the class of the String class (zero if the class is not tagged).
4349             <issue>Is this needed?</issue>
4350           </description>
4351         </param>
4352         <param id="size">
4353           <jlong/>
4354           <description>
4355             Size of the string (in bytes).
4356             See <functionlink id="GetObjectSize"/>.
4357           </description>
4358         </param>
4359         <param id="tag_ptr">
4360           <outptr><jlong/></outptr>
4361           <description>
4362             Points to the tag of the String object, or zero if the object is not
4363             tagged.
4364             To set the tag value to be associated with the object
4365             the agent sets the <code>jlong</code> pointed to by the parameter.
4366           </description>
4367         </param>
4368         <param id="value">
4369           <vmbuf><jchar/></vmbuf>
4370           <description>
4371             The value of the String, encoded as a Unicode string.
4372           </description>
4373         </param>
4374         <param id="value_length">
4375           <jint/>
4376           <description>
4377             The length of the string.
4378             The length is equal to the number of 16-bit Unicode
4379             characters in the string.
4380           </description>
4381         </param>
4382         <param id="user_data">
4383           <outptr><void/></outptr>
4384           <description>
4385             The user supplied data that was passed into the iteration function.
4386           </description>
4387         </param>
4388       </parameters>
4389     </callback>
4390 
4391 
4392     <callback id="jvmtiReservedCallback" since="1.1">
4393       <jint/>
4394       <synopsis>reserved for future use Callback</synopsis>
4395       <description>
4396         Placeholder -- reserved for future use.
4397       </description>
4398       <parameters>
4399       </parameters>
4400     </callback>
4401 
4402     <function id="FollowReferences" num="115" since="1.1">
4403       <synopsis>Follow References</synopsis>
4404       <description>
4405         This function initiates a traversal over the objects that are
4406         directly and indirectly reachable from the specified object or,
4407         if <code>initial_object</code> is not specified, all objects
4408         reachable from the heap roots.
4409         The heap root are the set of system classes,
4410         JNI globals, references from thread stacks, and other objects used as roots
4411         for the purposes of garbage collection.
4412         <p/>
4413         This function operates by traversing the reference graph.
4414         Let <i>A</i>, <i>B</i>, ... represent objects.
4415         When a reference from <i>A</i> to <i>B</i> is traversed,
4416         when a reference from a heap root to <i>B</i> is traversed,
4417         or when <i>B</i> is specified as the <paramlink id="initial_object"/>,
4418         then <i>B</i> is said to be <i>visited</i>.
4419         A reference from <i>A</i> to <i>B</i> is not traversed until <i>A</i>
4420         is visited.
4421         References are reported in the same order that the references are traversed.
4422         Object references are reported by invoking the agent supplied
4423         callback function <functionlink id="jvmtiHeapReferenceCallback"/>.
4424         In a reference from <i>A</i> to <i>B</i>, <i>A</i> is known
4425         as the <i>referrer</i> and <i>B</i> as the <i>referree</i>.
4426         The callback is invoked exactly once for each reference from a referrer;
4427         this is true even if there are reference cycles or multiple paths to
4428         the referrer.
4429         There may be more than one reference between a referrer and a referree,
4430         each reference is reported.
4431         These references may be distinguished by examining the
4432         <datalink
4433          id="jvmtiHeapReferenceCallback.reference_kind"><code>reference_kind</code></datalink>
4434          and
4435         <datalink
4436          id="jvmtiHeapReferenceCallback.reference_info"><code>reference_info</code></datalink>
4437         parameters of the <functionlink id="jvmtiHeapReferenceCallback"/> callback.
4438         <p/>
4439         This function reports a Java programming language view of object references,
4440         not a virtual machine implementation view. The following object references
4441         are reported when they are non-null:
4442         <ul>
4443           <li>Instance objects report references to each non-primitive instance fields
4444               (including inherited fields).</li>
4445           <li>Instance objects report a reference to the object type (class).</li>
4446           <li>Classes report a reference to the superclass and directly
4447               implemented/extended interfaces.</li>
4448           <li>Classes report a reference to the class loader, protection domain,
4449               signers, and resolved entries in the constant pool.</li>
4450           <li>Classes report a reference to each directly declared non-primitive
4451               static field.</li>
4452           <li>Arrays report a reference to the array type (class) and each
4453               array element.</li>
4454           <li>Primitive arrays report a reference to the array type.</li>
4455         </ul>
4456         <p/>
4457         This function can also be used to examine primitive (non-object) values.
4458         The primitive value of an array or String
4459         is reported after the object has been visited;
4460         it is reported by invoking the agent supplied callback function
4461         <functionlink id="jvmtiArrayPrimitiveValueCallback"/> or
4462         <functionlink id="jvmtiStringPrimitiveValueCallback"/>.
4463         A primitive field
4464         is reported after the object with that field is visited;
4465         it is reported by invoking the agent supplied callback function
4466         <functionlink id="jvmtiPrimitiveFieldCallback"/>.
4467         <p/>
4468         Whether a callback is provided or is <code>NULL</code> only determines
4469         whether the callback will be invoked, it does not influence
4470         which objects are visited nor does it influence whether other callbacks
4471         will be invoked.
4472         However, the
4473         <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>
4474         returned by <functionlink id="jvmtiHeapReferenceCallback"/>
4475         do determine if the objects referenced by the
4476         current object as visited.
4477         The <datalink id="jvmtiHeapFilter">heap filter flags</datalink>
4478         and <paramlink id="klass"/> provided as parameters to this function
4479         do not control which objects are visited but they do control which
4480         objects and primitive values are reported by the callbacks.
4481         For example, if the only callback that was set is
4482         <fieldlink id="array_primitive_value_callback" struct="jvmtiHeapCallbacks"/> and <code>klass</code>
4483         is set to the array of bytes class, then only arrays of byte will be
4484         reported.
4485         The table below summarizes this:
4486         <p/>
4487         <table>
4488           <tr class="bgLight">
4489             <th/>
4490             <th class="centered" scope="col">Controls objects visited</th>
4491             <th class="centered" scope="col">Controls objects reported</th>
4492             <th class="centered" scope="col">Controls primitives reported</th>
4493           </tr>
4494           <tr>
4495             <th scope="row">
4496               the
4497               <datalink id="jvmtiHeapVisitControl">Heap Visit Control Flags</datalink>
4498               returned by <functionlink id="jvmtiHeapReferenceCallback"/>
4499             </th>
4500             <td class="centered">
4501               <b>Yes</b>
4502             </td>
4503             <td class="centered">
4504               <b>Yes</b>, since visits are controlled
4505             </td>
4506             <td class="centered">
4507               <b>Yes</b>, since visits are controlled
4508             </td>
4509           </tr>
4510           <tr>
4511             <th scope="row">
4512               <fieldlink id="array_primitive_value_callback" struct="jvmtiHeapCallbacks"/>
4513               in <paramlink id="callbacks"/> set
4514             </th>
4515             <td class="centered">
4516               No
4517             </td>
4518             <td class="centered">
4519               <b>Yes</b>
4520             </td>
4521             <td class="centered">
4522               No
4523             </td>
4524           </tr>
4525           <tr>
4526             <th scope="row">
4527               <paramlink id="heap_filter"/>
4528             </th>
4529             <td class="centered">
4530               No
4531             </td>
4532             <td class="centered">
4533               <b>Yes</b>
4534             </td>
4535             <td class="centered">
4536               <b>Yes</b>
4537             </td>
4538           </tr>
4539           <tr>
4540             <th scope="row">
4541               <paramlink id="klass"/>
4542             </th>
4543             <td class="centered">
4544               No
4545             </td>
4546             <td class="centered">
4547               <b>Yes</b>
4548             </td>
4549             <td class="centered">
4550               <b>Yes</b>
4551             </td>
4552           </tr>
4553         </table>
4554         <p/>
4555         During the execution of this function the state of the heap
4556         does not change: no objects are allocated, no objects are
4557         garbage collected, and the state of objects (including
4558         held values) does not change.
4559         As a result, threads executing Java
4560         programming language code, threads attempting to resume the
4561         execution of Java programming language code, and threads
4562         attempting to execute JNI functions are typically stalled.
4563       </description>
4564       <origin>new</origin>
4565       <capabilities>
4566         <required id="can_tag_objects"></required>
4567       </capabilities>
4568       <parameters>
4569         <param id="heap_filter">
4570           <jint/>
4571           <description>
4572             This bit vector of
4573             <datalink id="jvmtiHeapFilter">heap filter flags</datalink>.
4574             restricts the objects for which the callback function is called.
4575             This applies to both the object and primitive callbacks.
4576           </description>
4577         </param>
4578         <param id="klass">
4579           <ptrtype>
4580             <jclass/>
4581             <nullok>callbacks are not limited to instances of a particular
4582                     class</nullok>
4583           </ptrtype>
4584           <description>
4585             Callbacks are only reported when the object is an instance of
4586             this class.
4587             Objects which are instances of a subclass of <code>klass</code>
4588             are not reported.
4589             If <code>klass</code> is an interface, no objects are reported.
4590             This applies to both the object and primitive callbacks.
4591           </description>
4592         </param>
4593         <param id="initial_object">
4594           <ptrtype>
4595             <jobject/>
4596             <nullok>references are followed from the heap roots</nullok>
4597           </ptrtype>
4598           <description>
4599             The object to follow
4600           </description>
4601         </param>
4602         <param id="callbacks">
4603           <inptr>
4604             <struct>jvmtiHeapCallbacks</struct>
4605           </inptr>
4606           <description>
4607             Structure defining the set of callback functions.
4608           </description>
4609         </param>
4610         <param id="user_data">
4611           <inbuf>
4612             <void/>
4613             <nullok><code>NULL</code> is passed as the user supplied data</nullok>
4614           </inbuf>
4615           <description>
4616             User supplied data to be passed to the callback.
4617           </description>
4618         </param>
4619       </parameters>
4620       <errors>
4621         <error id="JVMTI_ERROR_INVALID_CLASS">
4622           <paramlink id="klass"/> is not a valid class.
4623         </error>
4624         <error id="JVMTI_ERROR_INVALID_OBJECT">
4625           <paramlink id="initial_object"/> is not a valid object.
4626         </error>
4627       </errors>
4628     </function>
4629 
4630 
4631     <function id="IterateThroughHeap" num="116" since="1.1">
4632       <synopsis>Iterate Through Heap</synopsis>
4633       <description>
4634         Initiate an iteration over all objects in the heap.
4635         This includes both reachable and
4636         unreachable objects. Objects are visited in no particular order.
4637         <p/>
4638         Heap objects are reported by invoking the agent supplied
4639         callback function <functionlink id="jvmtiHeapIterationCallback"/>.
4640         References between objects are not reported.
4641         If only reachable objects are desired, or if object reference information
4642         is needed, use <functionlink id="FollowReferences"/>.
4643         <p/>
4644         This function can also be used to examine primitive (non-object) values.
4645         The primitive value of an array or String
4646         is reported after the object has been visited;
4647         it is reported by invoking the agent supplied callback function
4648         <functionlink id="jvmtiArrayPrimitiveValueCallback"/> or
4649         <functionlink id="jvmtiStringPrimitiveValueCallback"/>.
4650         A primitive field
4651         is reported after the object with that field is visited;
4652         it is reported by invoking the agent supplied
4653         callback function
4654         <functionlink id="jvmtiPrimitiveFieldCallback"/>.
4655         <p/>
4656         Unless the iteration is aborted by the
4657         <datalink id="jvmtiHeapVisitControl">Heap Visit Control Flags</datalink>
4658         returned by a callback, all objects in the heap are visited.
4659         Whether a callback is provided or is <code>NULL</code> only determines
4660         whether the callback will be invoked, it does not influence
4661         which objects are visited nor does it influence whether other callbacks
4662         will be invoked.
4663         The <datalink id="jvmtiHeapFilter">heap filter flags</datalink>
4664         and <paramlink id="klass"/> provided as parameters to this function
4665         do not control which objects are visited but they do control which
4666         objects and primitive values are reported by the callbacks.
4667         For example, if the only callback that was set is
4668         <fieldlink id="array_primitive_value_callback" struct="jvmtiHeapCallbacks"/> and <code>klass</code>
4669         is set to the array of bytes class, then only arrays of byte will be
4670         reported. The table below summarizes this (contrast this with
4671         <functionlink id="FollowReferences"/>):
4672         <p/>
4673         <table>
4674           <tr class="bgLight">
4675             <th/>
4676             <th class="centered" scope="col">Controls objects visited</th>
4677             <th class="centered" scope="col">Controls objects reported</th>
4678             <th class="centered" scope="col">Controls primitives reported</th>
4679           </tr>
4680           <tr>
4681             <th scope="row">
4682               the
4683               <datalink id="jvmtiHeapVisitControl">Heap Visit Control Flags</datalink>
4684               returned by <functionlink id="jvmtiHeapIterationCallback"/>
4685             </th>
4686             <td class="centered">
4687               No<br/>(unless they abort the iteration)
4688             </td>
4689             <td class="centered">
4690               No<br/>(unless they abort the iteration)
4691             </td>
4692             <td class="centered">
4693               No<br/>(unless they abort the iteration)
4694             </td>
4695           </tr>
4696           <tr>
4697             <th scope="row">
4698               <fieldlink id="array_primitive_value_callback" struct="jvmtiHeapCallbacks"/>
4699               in <paramlink id="callbacks"/> set
4700             </th>
4701             <td class="centered">
4702               No
4703             </td>
4704             <td class="centered">
4705               <b>Yes</b>
4706             </td>
4707             <td class="centered">
4708               No
4709             </td>
4710           </tr>
4711           <tr>
4712             <th scope="row">
4713               <paramlink id="heap_filter"/>
4714             </th>
4715             <td class="centered">
4716               No
4717             </td>
4718             <td class="centered">
4719               <b>Yes</b>
4720             </td>
4721             <td class="centered">
4722               <b>Yes</b>
4723             </td>
4724           </tr>
4725           <tr>
4726             <th scope="row">
4727               <paramlink id="klass"/>
4728             </th>
4729             <td class="centered">
4730               No
4731             </td>
4732             <td class="centered">
4733               <b>Yes</b>
4734             </td>
4735             <td class="centered">
4736               <b>Yes</b>
4737             </td>
4738           </tr>
4739         </table>
4740         <p/>
4741         During the execution of this function the state of the heap
4742         does not change: no objects are allocated, no objects are
4743         garbage collected, and the state of objects (including
4744         held values) does not change.
4745         As a result, threads executing Java
4746         programming language code, threads attempting to resume the
4747         execution of Java programming language code, and threads
4748         attempting to execute JNI functions are typically stalled.
4749       </description>
4750       <origin>new</origin>
4751       <capabilities>
4752         <required id="can_tag_objects"></required>
4753       </capabilities>
4754       <parameters>
4755         <param id="heap_filter">
4756           <jint/>
4757           <description>
4758             This bit vector of
4759             <datalink id="jvmtiHeapFilter">heap filter flags</datalink>.
4760             restricts the objects for which the callback function is called.
4761             This applies to both the object and primitive callbacks.
4762           </description>
4763         </param>
4764         <param id="klass">
4765           <ptrtype>
4766             <jclass/>
4767             <nullok>callbacks are not limited to instances of a particular class</nullok>
4768           </ptrtype>
4769           <description>
4770             Callbacks are only reported when the object is an instance of
4771             this class.
4772             Objects which are instances of a subclass of <code>klass</code>
4773             are not reported.
4774             If <code>klass</code> is an interface, no objects are reported.
4775             This applies to both the object and primitive callbacks.
4776           </description>
4777         </param>
4778         <param id="callbacks">
4779           <inptr>
4780             <struct>jvmtiHeapCallbacks</struct>
4781           </inptr>
4782           <description>
4783             Structure defining the set callback functions.
4784           </description>
4785         </param>
4786         <param id="user_data">
4787           <inbuf>
4788             <void/>
4789             <nullok><code>NULL</code> is passed as the user supplied data</nullok>
4790           </inbuf>
4791           <description>
4792             User supplied data to be passed to the callback.
4793           </description>
4794         </param>
4795       </parameters>
4796       <errors>
4797         <error id="JVMTI_ERROR_INVALID_CLASS">
4798           <paramlink id="klass"/> is not a valid class.
4799         </error>
4800       </errors>
4801     </function>
4802 
4803     <function id="GetTag" phase="start" num="106">
4804       <synopsis>Get Tag</synopsis>
4805       <description>
4806         Retrieve the tag associated with an object.
4807         The tag is a long value typically used to store a
4808         unique identifier or pointer to object information.
4809         The tag is set with
4810         <functionlink id="SetTag"></functionlink>.
4811         Objects for which no tags have been set return a
4812         tag value of zero.
4813       </description>
4814       <origin>new</origin>
4815       <capabilities>
4816         <required id="can_tag_objects"></required>
4817       </capabilities>
4818       <parameters>
4819         <param id="object">
4820           <jobject/>
4821             <description>
4822               The object whose tag is to be retrieved.
4823             </description>
4824         </param>
4825         <param id="tag_ptr">
4826           <outptr><jlong/></outptr>
4827           <description>
4828             On return, the referenced long is set to the value
4829             of the tag.
4830           </description>
4831         </param>
4832       </parameters>
4833       <errors>
4834       </errors>
4835     </function>
4836 
4837     <function id="SetTag" phase="start" num="107">
4838       <synopsis>Set Tag</synopsis>
4839       <description>
4840         Set the tag associated with an object.
4841         The tag is a long value typically used to store a
4842         unique identifier or pointer to object information.
4843         The tag is visible with
4844         <functionlink id="GetTag"></functionlink>.
4845       </description>
4846       <origin>new</origin>
4847       <capabilities>
4848         <required id="can_tag_objects"></required>
4849       </capabilities>
4850       <parameters>
4851         <param id="object">
4852           <jobject/>
4853             <description>
4854               The object whose tag is to be set.
4855             </description>
4856         </param>
4857         <param id="tag">
4858           <jlong/>
4859           <description>
4860             The new value of the tag.
4861           </description>
4862         </param>
4863       </parameters>
4864       <errors>
4865       </errors>
4866     </function>
4867 
4868     <function id="GetObjectsWithTags" num="114">
4869       <synopsis>Get Objects With Tags</synopsis>
4870       <description>
4871         Return objects in the heap with the specified tags.
4872         The format is parallel arrays of objects and tags.
4873       </description>
4874       <origin>new</origin>
4875       <capabilities>
4876         <required id="can_tag_objects"></required>
4877       </capabilities>
4878       <parameters>
4879         <param id="tag_count">
4880           <jint min="0"/>
4881             <description>
4882               Number of tags to scan for.
4883             </description>
4884         </param>
4885         <param id="tags">
4886           <inbuf incount="tag_count">
4887             <jlong/>
4888           </inbuf>
4889             <description>
4890               Scan for objects with these tags.
4891               Zero is not permitted in this array.
4892             </description>
4893         </param>
4894         <param id="count_ptr">
4895           <outptr>
4896             <jint/>
4897           </outptr>
4898             <description>
4899               Return the number of objects with any of the tags
4900               in <paramlink id="tags"/>.
4901             </description>
4902         </param>
4903         <param id="object_result_ptr">
4904           <allocbuf outcount="count_ptr">
4905             <jobject/>
4906             <nullok>this information is not returned</nullok>
4907           </allocbuf>
4908             <description>
4909               Returns the array of objects with any of the tags
4910               in <paramlink id="tags"/>.
4911             </description>
4912         </param>
4913         <param id="tag_result_ptr">
4914           <allocbuf outcount="count_ptr">
4915             <jlong/>
4916             <nullok>this information is not returned</nullok>
4917           </allocbuf>
4918             <description>
4919               For each object in <paramlink id="object_result_ptr"/>,
4920               return the tag at the corresponding index.
4921             </description>
4922         </param>
4923       </parameters>
4924       <errors>
4925         <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
4926           Zero is present in <paramlink id="tags"></paramlink>.
4927         </error>
4928       </errors>
4929     </function>
4930 
4931     <function id="ForceGarbageCollection" num="108">
4932       <synopsis>Force Garbage Collection</synopsis>
4933       <description>
4934         Force the VM to perform a garbage collection.
4935         The garbage collection is as complete as possible.
4936         This function does not cause finalizers to be run.
4937         This function does not return until the garbage collection
4938         is finished.
4939         <p/>
4940         Although garbage collection is as complete
4941         as possible there is no guarantee that all
4942         <eventlink id="ObjectFree"/>
4943         events will have been
4944         sent by the time that this function
4945         returns. In particular, an object may be
4946         prevented from being freed because it
4947         is awaiting finalization.
4948       </description>
4949       <origin>new</origin>
4950       <capabilities>
4951       </capabilities>
4952       <parameters>
4953       </parameters>
4954       <errors>
4955       </errors>
4956     </function>
4957 
4958 
4959   </category>
4960 
4961   <category id="Heap_1_0" label="Heap (1.0)">
4962     <intro>
4963       <b>
4964         These functions and data types were introduced in the original
4965         <jvmti/> version 1.0 and have been superseded by more
4966       </b>
4967       <internallink id="Heap"><b>powerful and flexible versions</b></internallink>
4968       <b>
4969         which:
4970       </b>
4971       <ul>
4972         <li>
4973           <b>
4974             Allow access to primitive values (the value of Strings, arrays,
4975             and primitive fields)
4976           </b>
4977         </li>
4978         <li>
4979           <b>
4980             Allow the tag of the referrer to be set, thus enabling more
4981             efficient localized reference graph building
4982           </b>
4983         </li>
4984         <li>
4985           <b>
4986             Provide more extensive filtering abilities
4987           </b>
4988         </li>
4989         <li>
4990           <b>
4991             Are extensible, allowing their abilities to grow in future versions of <jvmti/>
4992           </b>
4993         </li>
4994       </ul>
4995       <p/>
4996       <b>Please use the </b>
4997       <internallink id="Heap"><b>current Heap functions</b></internallink>.
4998         <p/>
4999         <constants id="jvmtiHeapObjectFilter" label="Heap Object Filter Enumeration" kind="enum">
5000           <constant id="JVMTI_HEAP_OBJECT_TAGGED" num="1">
5001             Tagged objects only.
5002           </constant>
5003           <constant id="JVMTI_HEAP_OBJECT_UNTAGGED" num="2">
5004             Untagged objects only.
5005           </constant>
5006           <constant id="JVMTI_HEAP_OBJECT_EITHER" num="3">
5007             Either tagged or untagged objects.
5008           </constant>
5009         </constants>
5010 
5011         <constants id="jvmtiHeapRootKind" label="Heap Root Kind Enumeration" kind="enum">
5012           <constant id="JVMTI_HEAP_ROOT_JNI_GLOBAL" num="1">
5013             JNI global reference.
5014           </constant>
5015           <constant id="JVMTI_HEAP_ROOT_SYSTEM_CLASS" num="2">
5016             System class.
5017           </constant>
5018           <constant id="JVMTI_HEAP_ROOT_MONITOR" num="3">
5019             Monitor.
5020           </constant>
5021           <constant id="JVMTI_HEAP_ROOT_STACK_LOCAL" num="4">
5022             Stack local.
5023           </constant>
5024           <constant id="JVMTI_HEAP_ROOT_JNI_LOCAL" num="5">
5025             JNI local reference.
5026           </constant>
5027           <constant id="JVMTI_HEAP_ROOT_THREAD" num="6">
5028             Thread.
5029           </constant>
5030           <constant id="JVMTI_HEAP_ROOT_OTHER" num="7">
5031             Other.
5032           </constant>
5033         </constants>
5034 
5035         <constants id="jvmtiObjectReferenceKind" label="Object Reference Enumeration" kind="enum">
5036           <constant id="JVMTI_REFERENCE_CLASS" num="1">
5037             Reference from an object to its class.
5038           </constant>
5039           <constant id="JVMTI_REFERENCE_FIELD" num="2">
5040             Reference from an object to the value of one of its instance fields.
5041             For references of this kind the <code>referrer_index</code>
5042             parameter to the <internallink id="jvmtiObjectReferenceCallback">
5043             jvmtiObjectReferenceCallback</internallink> is the index of the
5044             the instance field. The index is based on the order of all the
5045             object's fields. This includes all fields of the directly declared
5046             static and instance fields in the class, and includes all fields (both
5047             public and private) fields declared in superclasses and superinterfaces.
5048             The index is thus calculated by summing the index of the field in the directly
5049             declared class (see <functionlink id="GetClassFields"/>), with the total
5050             number of fields (both public and private) declared in all superclasses
5051             and superinterfaces. The index starts at zero.
5052           </constant>
5053           <constant id="JVMTI_REFERENCE_ARRAY_ELEMENT" num="3">
5054             Reference from an array to one of its elements.
5055             For references of this kind the <code>referrer_index</code>
5056             parameter to the <internallink id="jvmtiObjectReferenceCallback">
5057             jvmtiObjectReferenceCallback</internallink> is the array index.
5058           </constant>
5059           <constant id="JVMTI_REFERENCE_CLASS_LOADER" num="4">
5060             Reference from a class to its class loader.
5061           </constant>
5062           <constant id="JVMTI_REFERENCE_SIGNERS" num="5">
5063             Reference from a class to its signers array.
5064           </constant>
5065           <constant id="JVMTI_REFERENCE_PROTECTION_DOMAIN" num="6">
5066             Reference from a class to its protection domain.
5067           </constant>
5068           <constant id="JVMTI_REFERENCE_INTERFACE" num="7">
5069             Reference from a class to one of its interfaces.
5070           </constant>
5071           <constant id="JVMTI_REFERENCE_STATIC_FIELD" num="8">
5072             Reference from a class to the value of one of its static fields.
5073             For references of this kind the <code>referrer_index</code>
5074             parameter to the <internallink id="jvmtiObjectReferenceCallback">
5075             jvmtiObjectReferenceCallback</internallink> is the index of the
5076             the static field. The index is based on the order of all the
5077             object's fields. This includes all fields of the directly declared
5078             static and instance fields in the class, and includes all fields (both
5079             public and private) fields declared in superclasses and superinterfaces.
5080             The index is thus calculated by summing the index of the field in the directly
5081             declared class (see <functionlink id="GetClassFields"/>), with the total
5082             number of fields (both public and private) declared in all superclasses
5083             and superinterfaces. The index starts at zero.
5084             Note: this definition differs from that in the <jvmti/> 1.0 Specification.
5085             <rationale>No known implementations used the 1.0 definition.</rationale>
5086           </constant>
5087           <constant id="JVMTI_REFERENCE_CONSTANT_POOL" num="9">
5088             Reference from a class to a resolved entry in the constant pool.
5089             For references of this kind the <code>referrer_index</code>
5090             parameter to the <internallink id="jvmtiObjectReferenceCallback">
5091             jvmtiObjectReferenceCallback</internallink> is the index into
5092             constant pool table of the class, starting at 1. See
5093             <vmspec chapter="4.4"/>.
5094           </constant>
5095         </constants>
5096 
5097         <constants id="jvmtiIterationControl" label="Iteration Control Enumeration" kind="enum">
5098           <constant id="JVMTI_ITERATION_CONTINUE" num="1">
5099             Continue the iteration.
5100             If this is a reference iteration, follow the references of this object.
5101           </constant>
5102           <constant id="JVMTI_ITERATION_IGNORE" num="2">
5103             Continue the iteration.
5104             If this is a reference iteration, ignore the references of this object.
5105           </constant>
5106           <constant id="JVMTI_ITERATION_ABORT" num="0">
5107             Abort the iteration.
5108           </constant>
5109         </constants>
5110     </intro>
5111 
5112     <callback id="jvmtiHeapObjectCallback">
5113       <enum>jvmtiIterationControl</enum>
5114       <synopsis>Heap Object Callback</synopsis>
5115       <description>
5116         Agent supplied callback function.
5117         Describes (but does not pass in) an object in the heap.
5118         <p/>
5119         Return value should be <code>JVMTI_ITERATION_CONTINUE</code> to continue iteration,
5120         or <code>JVMTI_ITERATION_ABORT</code> to stop iteration.
5121         <p/>
5122         See the <internallink id="heapCallbacks">heap callback
5123         function restrictions</internallink>.
5124       </description>
5125       <parameters>
5126         <param id="class_tag">
5127           <jlong/>
5128           <description>
5129             The tag of the class of object (zero if the class is not tagged).
5130             If the object represents a runtime class,
5131             the <code>class_tag</code> is the tag
5132             associated with <code>java.lang.Class</code>
5133             (zero if <code>java.lang.Class</code> is not tagged).
5134           </description>
5135         </param>
5136         <param id="size">
5137           <jlong/>
5138           <description>
5139             Size of the object (in bytes). See <functionlink id="GetObjectSize"/>.
5140           </description>
5141         </param>
5142         <param id="tag_ptr">
5143           <outptr><jlong/></outptr>
5144           <description>
5145             The object tag value, or zero if the object is not tagged.
5146             To set the tag value to be associated with the object
5147             the agent sets the <code>jlong</code> pointed to by the parameter.
5148           </description>
5149         </param>
5150         <param id="user_data">
5151           <outptr><void/></outptr>
5152           <description>
5153             The user supplied data that was passed into the iteration function.
5154           </description>
5155         </param>
5156       </parameters>
5157     </callback>
5158 
5159     <callback id="jvmtiHeapRootCallback">
5160       <enum>jvmtiIterationControl</enum>
5161       <synopsis>Heap Root Object Callback</synopsis>
5162       <description>
5163         Agent supplied callback function.
5164         Describes (but does not pass in) an object that is a root for the purposes
5165         of garbage collection.
5166         <p/>
5167         Return value should be <code>JVMTI_ITERATION_CONTINUE</code> to continue iteration,
5168         <code>JVMTI_ITERATION_IGNORE</code> to continue iteration without pursuing
5169         references from referree object or <code>JVMTI_ITERATION_ABORT</code> to stop iteration.
5170         <p/>
5171         See the <internallink id="heapCallbacks">heap callback
5172         function restrictions</internallink>.
5173       </description>
5174       <parameters>
5175         <param id="root_kind">
5176           <enum>jvmtiHeapRootKind</enum>
5177           <description>
5178             The kind of heap root.
5179           </description>
5180         </param>
5181         <param id="class_tag">
5182           <jlong/>
5183           <description>
5184             The tag of the class of object (zero if the class is not tagged).
5185             If the object represents a runtime class, the <code>class_tag</code> is the tag
5186             associated with <code>java.lang.Class</code>
5187             (zero if <code>java.lang.Class</code> is not tagged).
5188           </description>
5189         </param>
5190         <param id="size">
5191           <jlong/>
5192           <description>
5193             Size of the object (in bytes). See <functionlink id="GetObjectSize"/>.
5194           </description>
5195         </param>
5196         <param id="tag_ptr">
5197           <outptr><jlong/></outptr>
5198           <description>
5199             The object tag value, or zero if the object is not tagged.
5200             To set the tag value to be associated with the object
5201             the agent sets the <code>jlong</code> pointed to by the parameter.
5202           </description>
5203         </param>
5204         <param id="user_data">
5205           <outptr><void/></outptr>
5206           <description>
5207             The user supplied data that was passed into the iteration function.
5208           </description>
5209         </param>
5210       </parameters>
5211     </callback>
5212 
5213     <callback id="jvmtiStackReferenceCallback">
5214       <enum>jvmtiIterationControl</enum>
5215       <synopsis>Stack Reference Object Callback</synopsis>
5216       <description>
5217         Agent supplied callback function.
5218         Describes (but does not pass in) an object on the stack that is a root for
5219         the purposes of garbage collection.
5220         <p/>
5221         Return value should be <code>JVMTI_ITERATION_CONTINUE</code> to continue iteration,
5222         <code>JVMTI_ITERATION_IGNORE</code> to continue iteration without pursuing
5223         references from referree object or <code>JVMTI_ITERATION_ABORT</code> to stop iteration.
5224         <p/>
5225         See the <internallink id="heapCallbacks">heap callback
5226         function restrictions</internallink>.
5227       </description>
5228       <parameters>
5229         <param id="root_kind">
5230           <enum>jvmtiHeapRootKind</enum>
5231           <description>
5232             The kind of root (either <code>JVMTI_HEAP_ROOT_STACK_LOCAL</code> or
5233             <code>JVMTI_HEAP_ROOT_JNI_LOCAL</code>).
5234           </description>
5235         </param>
5236         <param id="class_tag">
5237           <jlong/>
5238           <description>
5239            The tag of the class of object (zero if the class is not tagged).
5240            If the object represents a runtime class, the  <code>class_tag</code> is the tag
5241            associated with <code>java.lang.Class</code>
5242            (zero if <code>java.lang.Class</code> is not tagged).
5243           </description>
5244         </param>
5245         <param id="size">
5246           <jlong/>
5247           <description>
5248             Size of the object (in bytes). See <functionlink id="GetObjectSize"/>.
5249           </description>
5250         </param>
5251         <param id="tag_ptr">
5252           <outptr><jlong/></outptr>
5253           <description>
5254             The object tag value, or zero if the object is not tagged.
5255             To set the tag value to be associated with the object
5256             the agent sets the <code>jlong</code> pointed to by the parameter.
5257           </description>
5258         </param>
5259         <param id="thread_tag">
5260           <jlong/>
5261           <description>
5262             The tag of the thread corresponding to this stack, zero if not tagged.
5263           </description>
5264         </param>
5265         <param id="depth">
5266           <jint/>
5267           <description>
5268             The depth of the frame.
5269           </description>
5270         </param>
5271         <param id="method">
5272           <jmethodID/>
5273           <description>
5274             The method executing in this frame.
5275           </description>
5276         </param>
5277         <param id="slot">
5278           <jint/>
5279           <description>
5280             The slot number.
5281           </description>
5282         </param>
5283         <param id="user_data">
5284           <outptr><void/></outptr>
5285           <description>
5286             The user supplied data that was passed into the iteration function.
5287           </description>
5288         </param>
5289       </parameters>
5290     </callback>
5291 
5292     <callback id="jvmtiObjectReferenceCallback">
5293       <enum>jvmtiIterationControl</enum>
5294       <synopsis>Object Reference Callback</synopsis>
5295       <description>
5296         Agent supplied callback function.
5297         Describes a reference from an object (the referrer) to another object
5298         (the referree).
5299         <p/>
5300         Return value should be <code>JVMTI_ITERATION_CONTINUE</code> to continue iteration,
5301         <code>JVMTI_ITERATION_IGNORE</code> to continue iteration without pursuing
5302         references from referree object or <code>JVMTI_ITERATION_ABORT</code> to stop iteration.
5303         <p/>
5304         See the <internallink id="heapCallbacks">heap callback
5305         function restrictions</internallink>.
5306       </description>
5307       <parameters>
5308         <param id="reference_kind">
5309           <enum>jvmtiObjectReferenceKind</enum>
5310           <description>
5311             The type of reference.
5312           </description>
5313         </param>
5314         <param id="class_tag">
5315           <jlong/>
5316           <description>
5317             The tag of the class of referree object (zero if the class is not tagged).
5318             If the referree object represents a runtime class,
5319             the  <code>class_tag</code> is the tag
5320             associated with <code>java.lang.Class</code>
5321             (zero if <code>java.lang.Class</code> is not tagged).
5322           </description>
5323         </param>
5324         <param id="size">
5325           <jlong/>
5326           <description>
5327             Size of the referree object (in bytes).
5328             See <functionlink id="GetObjectSize"/>.
5329           </description>
5330         </param>
5331         <param id="tag_ptr">
5332           <outptr><jlong/></outptr>
5333           <description>
5334             The referree object tag value, or zero if the object is not
5335             tagged.
5336             To set the tag value to be associated with the object
5337             the agent sets the <code>jlong</code> pointed to by the parameter.
5338           </description>
5339         </param>
5340         <param id="referrer_tag">
5341           <jlong/>
5342           <description>
5343             The tag of the referrer object, or zero if the referrer
5344             object is not tagged.
5345           </description>
5346         </param>
5347         <param id="referrer_index">
5348           <jint/>
5349           <description>
5350             For references of type <code>JVMTI_REFERENCE_FIELD</code> or
5351             <code>JVMTI_REFERENCE_STATIC_FIELD</code> the index
5352             of the field in the referrer object. The index is based on the
5353             order of all the object's fields - see <internallink
5354             id="JVMTI_REFERENCE_FIELD">JVMTI_REFERENCE_FIELD</internallink>
5355             or <internallink
5356             id="JVMTI_REFERENCE_STATIC_FIELD">JVMTI_REFERENCE_STATIC_FIELD
5357             </internallink> for further description.
5358             <p/>
5359             For references of type <code>JVMTI_REFERENCE_ARRAY_ELEMENT</code>
5360             the array index - see <internallink id="JVMTI_REFERENCE_ARRAY_ELEMENT">
5361             JVMTI_REFERENCE_ARRAY_ELEMENT</internallink> for further description.
5362             <p/>
5363             For references of type <code>JVMTI_REFERENCE_CONSTANT_POOL</code>
5364             the index into the constant pool of the class - see
5365             <internallink id="JVMTI_REFERENCE_CONSTANT_POOL">
5366             JVMTI_REFERENCE_CONSTANT_POOL</internallink> for further
5367             description.
5368             <p/>
5369             For references of other kinds the <code>referrer_index</code> is
5370             <code>-1</code>.
5371           </description>
5372         </param>
5373         <param id="user_data">
5374           <outptr><void/></outptr>
5375           <description>
5376             The user supplied data that was passed into the iteration function.
5377           </description>
5378         </param>
5379       </parameters>
5380     </callback>
5381 
5382     <function id="IterateOverObjectsReachableFromObject" num="109">
5383       <synopsis>Iterate Over Objects Reachable From Object</synopsis>
5384       <description>
5385         This function iterates over all objects that are directly
5386         and indirectly reachable from the specified object.
5387         For each object <i>A</i> (known
5388         as the referrer) with a reference to object <i>B</i> the specified
5389         callback function is called to describe the object reference.
5390         The callback is called exactly once for each reference from a referrer;
5391         this is true even if there are reference cycles or multiple paths to
5392         the referrer.
5393         There may be more than one reference between a referrer and a referree,
5394         These may be distinguished by the
5395         <datalink id="jvmtiObjectReferenceCallback.reference_kind"></datalink> and
5396         <datalink id="jvmtiObjectReferenceCallback.referrer_index"></datalink>.
5397         The callback for an object will always occur after the callback for
5398         its referrer.
5399         <p/>
5400         See <functionlink id="FollowReferences"/> for the object
5401         references which are reported.
5402         <p/>
5403         During the execution of this function the state of the heap
5404         does not change: no objects are allocated, no objects are
5405         garbage collected, and the state of objects (including
5406         held values) does not change.
5407         As a result, threads executing Java
5408         programming language code, threads attempting to resume the
5409         execution of Java programming language code, and threads
5410         attempting to execute JNI functions are typically stalled.
5411       </description>
5412       <origin>new</origin>
5413       <capabilities>
5414         <required id="can_tag_objects"></required>
5415       </capabilities>
5416       <parameters>
5417         <param id="object">
5418           <jobject/>
5419             <description>
5420               The object
5421             </description>
5422         </param>
5423         <param id="object_reference_callback">
5424           <ptrtype>
5425             <struct>jvmtiObjectReferenceCallback</struct>
5426           </ptrtype>
5427             <description>
5428               The callback to be called to describe each
5429               object reference.
5430             </description>
5431         </param>
5432         <param id="user_data">
5433           <inbuf>
5434             <void/>
5435             <nullok><code>NULL</code> is passed as the user supplied data</nullok>
5436           </inbuf>
5437           <description>
5438             User supplied data to be passed to the callback.
5439           </description>
5440         </param>
5441       </parameters>
5442       <errors>
5443       </errors>
5444     </function>
5445 
5446     <function id="IterateOverReachableObjects" num="110">
5447       <synopsis>Iterate Over Reachable Objects</synopsis>
5448       <description>
5449         This function iterates over the root objects and all objects that
5450         are directly and indirectly reachable from the root objects.
5451         The root objects comprise the set of system classes,
5452         JNI globals, references from thread stacks, and other objects used as roots
5453         for the purposes of garbage collection.
5454         <p/>
5455         For each root the <paramlink id="heap_root_callback"></paramlink>
5456         or <paramlink id="stack_ref_callback"></paramlink> callback is called.
5457         An object can be a root object for more than one reason and in that case
5458         the appropriate callback is called for each reason.
5459         <p/>
5460         For each object reference the <paramlink id="object_ref_callback"></paramlink>
5461         callback function is called to describe the object reference.
5462         The callback is called exactly once for each reference from a referrer;
5463         this is true even if there are reference cycles or multiple paths to
5464         the referrer.
5465         There may be more than one reference between a referrer and a referree,
5466         These may be distinguished by the
5467         <datalink id="jvmtiObjectReferenceCallback.reference_kind"></datalink> and
5468         <datalink id="jvmtiObjectReferenceCallback.referrer_index"></datalink>.
5469         The callback for an object will always occur after the callback for
5470         its referrer.
5471         <p/>
5472         See <functionlink id="FollowReferences"/> for the object
5473         references which are reported.
5474         <p/>
5475         Roots are always reported to the profiler before any object references
5476         are reported. In other words, the <paramlink id="object_ref_callback"></paramlink>
5477         callback will not be called until the appropriate callback has been called
5478         for all roots. If the <paramlink id="object_ref_callback"></paramlink> callback is
5479         specified as <code>NULL</code> then this function returns after
5480         reporting the root objects to the profiler.
5481         <p/>
5482         During the execution of this function the state of the heap
5483         does not change: no objects are allocated, no objects are
5484         garbage collected, and the state of objects (including
5485         held values) does not change.
5486         As a result, threads executing Java
5487         programming language code, threads attempting to resume the
5488         execution of Java programming language code, and threads
5489         attempting to execute JNI functions are typically stalled.
5490       </description>
5491       <origin>new</origin>
5492       <capabilities>
5493         <required id="can_tag_objects"></required>
5494       </capabilities>
5495       <parameters>
5496         <param id="heap_root_callback">
5497           <ptrtype>
5498             <struct>jvmtiHeapRootCallback</struct>
5499             <nullok>do not report heap roots</nullok>
5500           </ptrtype>
5501             <description>
5502               The callback function to be called for each heap root of type
5503               <code>JVMTI_HEAP_ROOT_JNI_GLOBAL</code>,
5504               <code>JVMTI_HEAP_ROOT_SYSTEM_CLASS</code>,
5505               <code>JVMTI_HEAP_ROOT_MONITOR</code>,
5506               <code>JVMTI_HEAP_ROOT_THREAD</code>, or
5507               <code>JVMTI_HEAP_ROOT_OTHER</code>.
5508             </description>
5509         </param>
5510         <param id="stack_ref_callback">
5511           <ptrtype>
5512             <struct>jvmtiStackReferenceCallback</struct>
5513             <nullok>do not report stack references</nullok>
5514           </ptrtype>
5515             <description>
5516               The callback function to be called for each heap root of
5517               <code>JVMTI_HEAP_ROOT_STACK_LOCAL</code> or
5518               <code>JVMTI_HEAP_ROOT_JNI_LOCAL</code>.
5519             </description>
5520         </param>
5521         <param id="object_ref_callback">
5522           <ptrtype>
5523             <struct>jvmtiObjectReferenceCallback</struct>
5524             <nullok>do not follow references from the root objects</nullok>
5525           </ptrtype>
5526             <description>
5527               The callback function to be called for each object reference.
5528             </description>
5529         </param>
5530         <param id="user_data">
5531           <inbuf>
5532             <void/>
5533             <nullok><code>NULL</code> is passed as the user supplied data</nullok>
5534           </inbuf>
5535           <description>
5536             User supplied data to be passed to the callback.
5537           </description>
5538         </param>
5539       </parameters>
5540       <errors>
5541       </errors>
5542     </function>
5543 
5544     <function id="IterateOverHeap" num="111">
5545       <synopsis>Iterate Over Heap</synopsis>
5546       <description>
5547         Iterate over all objects in the heap. This includes both reachable and
5548         unreachable objects.
5549         <p/>
5550         The <paramlink id="object_filter"></paramlink> parameter indicates the
5551         objects for which the callback function is called. If this parameter
5552         is <code>JVMTI_HEAP_OBJECT_TAGGED</code> then the callback will only be
5553         called for every object that is tagged. If the parameter is
5554         <code>JVMTI_HEAP_OBJECT_UNTAGGED</code> then the callback will only be
5555         for objects that are not tagged. If the parameter
5556         is <code>JVMTI_HEAP_OBJECT_EITHER</code> then the callback will be
5557         called for every object in the heap, irrespective of whether it is
5558         tagged or not.
5559         <p/>
5560         During the execution of this function the state of the heap
5561         does not change: no objects are allocated, no objects are
5562         garbage collected, and the state of objects (including
5563         held values) does not change.
5564         As a result, threads executing Java
5565         programming language code, threads attempting to resume the
5566         execution of Java programming language code, and threads
5567         attempting to execute JNI functions are typically stalled.
5568       </description>
5569       <origin>new</origin>
5570       <capabilities>
5571         <required id="can_tag_objects"></required>
5572       </capabilities>
5573       <parameters>
5574         <param id="object_filter">
5575           <enum>jvmtiHeapObjectFilter</enum>
5576           <description>
5577             Indicates the objects for which the callback function is called.
5578           </description>
5579         </param>
5580         <param id="heap_object_callback">
5581           <ptrtype>
5582             <struct>jvmtiHeapObjectCallback</struct>
5583           </ptrtype>
5584             <description>
5585               The iterator function to be called for each
5586               object matching the <paramlink id="object_filter"/>.
5587             </description>
5588         </param>
5589         <param id="user_data">
5590           <inbuf>
5591             <void/>
5592             <nullok><code>NULL</code> is passed as the user supplied data</nullok>
5593           </inbuf>
5594           <description>
5595             User supplied data to be passed to the callback.
5596           </description>
5597         </param>
5598       </parameters>
5599       <errors>
5600       </errors>
5601     </function>
5602 
5603     <function id="IterateOverInstancesOfClass" num="112">
5604       <synopsis>Iterate Over Instances Of Class</synopsis>
5605       <description>
5606         Iterate over all objects in the heap that are instances of the specified class.
5607         This includes direct instances of the specified class and
5608         instances of all subclasses of the specified class.
5609         This includes both reachable and unreachable objects.
5610         <p/>
5611         The <paramlink id="object_filter"></paramlink> parameter indicates the
5612         objects for which the callback function is called. If this parameter
5613         is <code>JVMTI_HEAP_OBJECT_TAGGED</code> then the callback will only be
5614         called for every object that is tagged. If the parameter is
5615         <code>JVMTI_HEAP_OBJECT_UNTAGGED</code> then the callback will only be
5616         called for objects that are not tagged. If the parameter
5617         is <code>JVMTI_HEAP_OBJECT_EITHER</code> then the callback will be
5618         called for every object in the heap, irrespective of whether it is
5619         tagged or not.
5620         <p/>
5621         During the execution of this function the state of the heap
5622         does not change: no objects are allocated, no objects are
5623         garbage collected, and the state of objects (including
5624         held values) does not change.
5625         As a result, threads executing Java
5626         programming language code, threads attempting to resume the
5627         execution of Java programming language code, and threads
5628         attempting to execute JNI functions are typically stalled.
5629       </description>
5630       <origin>new</origin>
5631       <capabilities>
5632         <required id="can_tag_objects"></required>
5633       </capabilities>
5634       <parameters>
5635         <param id="klass">
5636           <jclass/>
5637             <description>
5638               Iterate over objects of this class only.
5639             </description>
5640         </param>
5641         <param id="object_filter">
5642           <enum>jvmtiHeapObjectFilter</enum>
5643           <description>
5644             Indicates the objects for which the callback function is called.
5645           </description>
5646         </param>
5647         <param id="heap_object_callback">
5648           <ptrtype>
5649             <struct>jvmtiHeapObjectCallback</struct>
5650           </ptrtype>
5651             <description>
5652               The iterator function to be called for each
5653               <paramlink id="klass"/> instance matching
5654               the <paramlink id="object_filter"/>.
5655             </description>
5656         </param>
5657         <param id="user_data">
5658           <inbuf>
5659             <void/>
5660             <nullok><code>NULL</code> is passed as the user supplied data</nullok>
5661           </inbuf>
5662           <description>
5663             User supplied data to be passed to the callback.
5664           </description>
5665         </param>
5666       </parameters>
5667       <errors>
5668       </errors>
5669     </function>
5670 
5671   </category>
5672 
5673   <category id="local" label="Local Variable">
5674 
5675     <intro>
5676       These functions are used to retrieve or set the value of a local variable.
5677       The variable is identified by the depth of the frame containing its
5678       value and the variable's slot number within that frame.
5679       The mapping of variables to
5680       slot numbers can be obtained with the function
5681       <functionlink id="GetLocalVariableTable"></functionlink>.
5682     </intro>
5683 
5684     <function id="GetLocalObject" num="21">
5685       <synopsis>Get Local Variable - Object</synopsis>
5686       <description>
5687         This function can be used to retrieve the value of a local
5688         variable whose type is <code>Object</code> or a subclass of <code>Object</code>.
5689       </description>
5690       <origin>jvmdi</origin>
5691       <capabilities>
5692         <required id="can_access_local_variables"></required>
5693       </capabilities>
5694       <parameters>
5695         <param id="thread">
5696           <jthread null="current" frame="frame"/>
5697           <description>
5698             The thread of the frame containing the variable's value.
5699           </description>
5700         </param>
5701         <param id="depth">
5702           <jframeID thread="thread"/>
5703           <description>
5704             The depth of the frame containing the variable's value.
5705           </description>
5706         </param>
5707         <param id="slot">
5708           <jint/>
5709           <description>
5710             The variable's slot number.
5711           </description>
5712         </param>
5713         <param id="value_ptr">
5714           <outptr><jobject/></outptr>
5715             <description>
5716               On return, points to the variable's value.
5717             </description>
5718         </param>
5719       </parameters>
5720       <errors>
5721         <error id="JVMTI_ERROR_INVALID_SLOT">
5722           Invalid <code>slot</code>.
5723         </error>
5724         <error id="JVMTI_ERROR_TYPE_MISMATCH">
5725           The variable type is not
5726           <code>Object</code> or a subclass of <code>Object</code>.
5727         </error>
5728         <error id="JVMTI_ERROR_OPAQUE_FRAME">
5729           Not a visible frame
5730         </error>
5731       </errors>
5732     </function>
5733 
5734     <function id="GetLocalInstance" num="155" since="1.2">
5735       <synopsis>Get Local Instance</synopsis>
5736       <description>
5737         This function can be used to retrieve the value of the local object
5738         variable at slot 0 (the "<code>this</code>" object) from non-static
5739         frames.  This function can retrieve the "<code>this</code>" object from
5740         native method frames, whereas <code>GetLocalObject()</code> would
5741         return <code>JVMTI_ERROR_OPAQUE_FRAME</code> in those cases.
5742       </description>
5743       <origin>new</origin>
5744       <capabilities>
5745         <required id="can_access_local_variables"></required>
5746       </capabilities>
5747       <parameters>
5748         <param id="thread">
5749           <jthread null="current" frame="frame"/>
5750           <description>
5751             The thread of the frame containing the variable's value.
5752           </description>
5753         </param>
5754         <param id="depth">
5755           <jframeID thread="thread"/>
5756           <description>
5757             The depth of the frame containing the variable's value.
5758           </description>
5759         </param>
5760         <param id="value_ptr">
5761           <outptr><jobject/></outptr>
5762             <description>
5763               On return, points to the variable's value.
5764             </description>
5765         </param>
5766       </parameters>
5767       <errors>
5768         <error id="JVMTI_ERROR_INVALID_SLOT">
5769           If the specified frame is a static method frame.
5770         </error>
5771       </errors>
5772     </function>
5773     <function id="GetLocalInt" num="22">
5774       <synopsis>Get Local Variable - Int</synopsis>
5775       <description>
5776         This function can be used to retrieve the value of a local
5777         variable whose type is <code>int</code>,
5778         <code>short</code>, <code>char</code>, <code>byte</code>, or
5779         <code>boolean</code>.
5780       </description>
5781       <origin>jvmdi</origin>
5782       <capabilities>
5783         <required id="can_access_local_variables"></required>
5784       </capabilities>
5785       <parameters>
5786         <param id="thread">
5787           <jthread null="current" frame="frame"/>
5788           <description>
5789             The thread of the frame containing the variable's value.
5790           </description>
5791         </param>
5792         <param id="depth">
5793           <jframeID thread="thread"/>
5794           <description>
5795             The depth of the frame containing the variable's value.
5796           </description>
5797         </param>
5798         <param id="slot">
5799           <jint/>
5800           <description>
5801             The variable's slot number.
5802           </description>
5803         </param>
5804         <param id="value_ptr">
5805           <outptr><jint/></outptr>
5806           <description>
5807             On return, points to the variable's value.
5808           </description>
5809         </param>
5810       </parameters>
5811       <errors>
5812         <error id="JVMTI_ERROR_INVALID_SLOT">
5813           Invalid <code>slot</code>.
5814         </error>
5815         <error id="JVMTI_ERROR_TYPE_MISMATCH">
5816           The variable type is not
5817           <code>int</code>, <code>short</code>,
5818           <code>char</code>, <code>byte</code>, or
5819           <code>boolean</code>.
5820         </error>
5821         <error id="JVMTI_ERROR_OPAQUE_FRAME">
5822           Not a visible frame
5823         </error>
5824       </errors>
5825     </function>
5826 
5827     <function id="GetLocalLong" num="23">
5828       <synopsis>Get Local Variable - Long</synopsis>
5829       <description>
5830         This function can be used to retrieve the value of a local
5831         variable whose type is <code>long</code>.
5832       </description>
5833       <origin>jvmdi</origin>
5834       <capabilities>
5835         <required id="can_access_local_variables"></required>
5836       </capabilities>
5837       <parameters>
5838         <param id="thread">
5839           <jthread null="current" frame="frame"/>
5840           <description>
5841             The thread of the frame containing the variable's value.
5842           </description>
5843         </param>
5844         <param id="depth">
5845           <jframeID thread="thread"/>
5846           <description>
5847             The depth of the frame containing the variable's value.
5848           </description>
5849         </param>
5850         <param id="slot">
5851           <jint/>
5852           <description>
5853             The variable's slot number.
5854           </description>
5855         </param>
5856         <param id="value_ptr">
5857           <outptr><jlong/></outptr>
5858           <description>
5859             On return, points to the variable's value.
5860           </description>
5861         </param>
5862       </parameters>
5863       <errors>
5864         <error id="JVMTI_ERROR_INVALID_SLOT">
5865           Invalid <code>slot</code>.
5866         </error>
5867         <error id="JVMTI_ERROR_TYPE_MISMATCH">
5868           The variable type is not <code>long</code>.
5869         </error>
5870         <error id="JVMTI_ERROR_OPAQUE_FRAME">
5871           Not a visible frame
5872         </error>
5873       </errors>
5874     </function>
5875 
5876     <function id="GetLocalFloat" num="24">
5877       <synopsis>Get Local Variable - Float</synopsis>
5878       <description>
5879         This function can be used to retrieve the value of a local
5880         variable whose type is <code>float</code>.
5881       </description>
5882       <origin>jvmdi</origin>
5883       <capabilities>
5884         <required id="can_access_local_variables"></required>
5885       </capabilities>
5886       <parameters>
5887         <param id="thread">
5888           <jthread null="current" frame="frame"/>
5889           <description>
5890             The thread of the frame containing the variable's value.
5891           </description>
5892         </param>
5893         <param id="depth">
5894           <jframeID thread="thread"/>
5895           <description>
5896             The depth of the frame containing the variable's value.
5897           </description>
5898         </param>
5899         <param id="slot">
5900           <jint/>
5901           <description>
5902             The variable's slot number.
5903           </description>
5904         </param>
5905         <param id="value_ptr">
5906           <outptr><jfloat/></outptr>
5907           <description>
5908             On return, points to the variable's value.
5909           </description>
5910         </param>
5911       </parameters>
5912       <errors>
5913         <error id="JVMTI_ERROR_INVALID_SLOT">
5914           Invalid <code>slot</code>.
5915         </error>
5916         <error id="JVMTI_ERROR_TYPE_MISMATCH">
5917           The variable type is not <code>float</code>.
5918         </error>
5919         <error id="JVMTI_ERROR_OPAQUE_FRAME">
5920           Not a visible frame
5921         </error>
5922       </errors>
5923     </function>
5924 
5925     <function id="GetLocalDouble" num="25">
5926       <synopsis>Get Local Variable - Double</synopsis>
5927       <description>
5928         This function can be used to retrieve the value of a local
5929         variable whose type is <code>long</code>.
5930       </description>
5931       <origin>jvmdi</origin>
5932       <capabilities>
5933         <required id="can_access_local_variables"></required>
5934       </capabilities>
5935       <parameters>
5936         <param id="thread">
5937           <jthread null="current" frame="frame"/>
5938           <description>
5939             The thread of the frame containing the variable's value.
5940           </description>
5941         </param>
5942         <param id="depth">
5943           <jframeID thread="thread"/>
5944           <description>
5945             The depth of the frame containing the variable's value.
5946           </description>
5947         </param>
5948         <param id="slot">
5949           <jint/>
5950           <description>
5951             The variable's slot number.
5952           </description>
5953         </param>
5954         <param id="value_ptr">
5955           <outptr><jdouble/></outptr>
5956           <description>
5957             On return, points to the variable's value.
5958           </description>
5959         </param>
5960       </parameters>
5961       <errors>
5962         <error id="JVMTI_ERROR_INVALID_SLOT">
5963           Invalid <code>slot</code>.
5964         </error>
5965         <error id="JVMTI_ERROR_TYPE_MISMATCH">
5966           The variable type is not <code>double</code>.
5967         </error>
5968         <error id="JVMTI_ERROR_OPAQUE_FRAME">
5969           Not a visible frame
5970         </error>
5971       </errors>
5972     </function>
5973 
5974     <function id="SetLocalObject" num="26">
5975       <synopsis>Set Local Variable - Object</synopsis>
5976       <description>
5977         This function can be used to set the value of a local
5978         variable whose type is <code>Object</code> or a subclass of <code>Object</code>.
5979       </description>
5980       <origin>jvmdi</origin>
5981       <capabilities>
5982         <required id="can_access_local_variables"></required>
5983       </capabilities>
5984       <parameters>
5985         <param id="thread">
5986           <jthread null="current" frame="frame"/>
5987           <description>
5988             The thread of the frame containing the variable's value.
5989           </description>
5990         </param>
5991         <param id="depth">
5992           <jframeID thread="thread"/>
5993           <description>
5994             The depth of the frame containing the variable's value.
5995           </description>
5996         </param>
5997         <param id="slot">
5998           <jint/>
5999           <description>
6000             The variable's slot number.
6001           </description>
6002         </param>
6003         <param id="value">
6004           <jobject/>
6005             <description>
6006               The new value for the variable.
6007             </description>
6008         </param>
6009       </parameters>
6010       <errors>
6011         <error id="JVMTI_ERROR_INVALID_SLOT">
6012           Invalid <code>slot</code>.
6013         </error>
6014         <error id="JVMTI_ERROR_TYPE_MISMATCH">
6015           The variable type is not
6016           <code>Object</code> or a subclass of <code>Object</code>.
6017         </error>
6018         <error id="JVMTI_ERROR_TYPE_MISMATCH">
6019           The supplied <paramlink id="value"/> is not compatible
6020           with the variable type.
6021         </error>
6022         <error id="JVMTI_ERROR_OPAQUE_FRAME">
6023           Not a visible frame
6024         </error>
6025       </errors>
6026     </function>
6027 
6028     <function id="SetLocalInt" num="27">
6029       <synopsis>Set Local Variable - Int</synopsis>
6030       <description>
6031         This function can be used to set the value of a local
6032         variable whose type is <code>int</code>,
6033         <code>short</code>, <code>char</code>, <code>byte</code>, or
6034         <code>boolean</code>.
6035       </description>
6036       <origin>jvmdi</origin>
6037       <capabilities>
6038         <required id="can_access_local_variables"></required>
6039       </capabilities>
6040       <parameters>
6041         <param id="thread">
6042           <jthread null="current" frame="frame"/>
6043           <description>
6044             The thread of the frame containing the variable's value.
6045           </description>
6046         </param>
6047         <param id="depth">
6048           <jframeID thread="thread"/>
6049           <description>
6050             The depth of the frame containing the variable's value.
6051           </description>
6052         </param>
6053         <param id="slot">
6054           <jint/>
6055           <description>
6056             The variable's slot number.
6057           </description>
6058         </param>
6059         <param id="value">
6060           <jint/>
6061           <description>
6062             The new value for the variable.
6063           </description>
6064         </param>
6065       </parameters>
6066       <errors>
6067         <error id="JVMTI_ERROR_INVALID_SLOT">
6068           Invalid <code>slot</code>.
6069         </error>
6070         <error id="JVMTI_ERROR_TYPE_MISMATCH">
6071           The variable type is not
6072           <code>int</code>, <code>short</code>,
6073           <code>char</code>, <code>byte</code>, or
6074           <code>boolean</code>.
6075         </error>
6076         <error id="JVMTI_ERROR_OPAQUE_FRAME">
6077           Not a visible frame
6078         </error>
6079       </errors>
6080     </function>
6081 
6082     <function id="SetLocalLong" num="28">
6083       <synopsis>Set Local Variable - Long</synopsis>
6084       <description>
6085         This function can be used to set the value of a local
6086         variable whose type is <code>long</code>.
6087       </description>
6088       <origin>jvmdi</origin>
6089       <capabilities>
6090         <required id="can_access_local_variables"></required>
6091       </capabilities>
6092       <parameters>
6093         <param id="thread">
6094           <jthread null="current" frame="frame"/>
6095           <description>
6096             The thread of the frame containing the variable's value.
6097           </description>
6098         </param>
6099         <param id="depth">
6100           <jframeID thread="thread"/>
6101           <description>
6102             The depth of the frame containing the variable's value.
6103           </description>
6104         </param>
6105         <param id="slot">
6106           <jint/>
6107           <description>
6108             The variable's slot number.
6109           </description>
6110         </param>
6111         <param id="value">
6112           <jlong/>
6113           <description>
6114             The new value for the variable.
6115           </description>
6116         </param>
6117       </parameters>
6118       <errors>
6119         <error id="JVMTI_ERROR_INVALID_SLOT">
6120           Invalid <code>slot</code>.
6121         </error>
6122         <error id="JVMTI_ERROR_TYPE_MISMATCH">
6123           The variable type is not <code>long</code>.
6124         </error>
6125         <error id="JVMTI_ERROR_OPAQUE_FRAME">
6126           Not a visible frame
6127         </error>
6128       </errors>
6129     </function>
6130 
6131     <function id="SetLocalFloat" num="29">
6132       <synopsis>Set Local Variable - Float</synopsis>
6133       <description>
6134         This function can be used to set the value of a local
6135         variable whose type is <code>float</code>.
6136       </description>
6137       <origin>jvmdi</origin>
6138       <capabilities>
6139         <required id="can_access_local_variables"></required>
6140       </capabilities>
6141       <parameters>
6142         <param id="thread">
6143           <jthread null="current" frame="frame"/>
6144           <description>
6145             The thread of the frame containing the variable's value.
6146           </description>
6147         </param>
6148         <param id="depth">
6149           <jframeID thread="thread"/>
6150           <description>
6151             The depth of the frame containing the variable's value.
6152           </description>
6153         </param>
6154         <param id="slot">
6155           <jint/>
6156           <description>
6157             The variable's slot number.
6158           </description>
6159         </param>
6160         <param id="value">
6161           <jfloat/>
6162           <description>
6163             The new value for the variable.
6164           </description>
6165         </param>
6166       </parameters>
6167       <errors>
6168         <error id="JVMTI_ERROR_INVALID_SLOT">
6169           Invalid <code>slot</code>.
6170         </error>
6171         <error id="JVMTI_ERROR_TYPE_MISMATCH">
6172           The variable type is not <code>float</code>.
6173         </error>
6174         <error id="JVMTI_ERROR_OPAQUE_FRAME">
6175           Not a visible frame
6176         </error>
6177       </errors>
6178     </function>
6179 
6180     <function id="SetLocalDouble" num="30">
6181       <synopsis>Set Local Variable - Double</synopsis>
6182       <description>
6183         This function can be used to set the value of a local
6184         variable whose type is <code>double</code>.
6185       </description>
6186       <origin>jvmdi</origin>
6187       <capabilities>
6188         <required id="can_access_local_variables"></required>
6189       </capabilities>
6190       <parameters>
6191         <param id="thread">
6192           <jthread null="current" frame="frame"/>
6193           <description>
6194             The thread of the frame containing the variable's value.
6195           </description>
6196         </param>
6197         <param id="depth">
6198           <jframeID thread="thread"/>
6199           <description>
6200             The depth of the frame containing the variable's value.
6201           </description>
6202         </param>
6203         <param id="slot">
6204           <jint/>
6205           <description>
6206             The variable's slot number.
6207           </description>
6208         </param>
6209         <param id="value">
6210           <jdouble/>
6211           <description>
6212             The new value for the variable.
6213           </description>
6214         </param>
6215       </parameters>
6216       <errors>
6217         <error id="JVMTI_ERROR_INVALID_SLOT">
6218           Invalid <code>slot</code>.
6219         </error>
6220         <error id="JVMTI_ERROR_TYPE_MISMATCH">
6221           The variable type is not <code>double</code>.
6222         </error>
6223         <error id="JVMTI_ERROR_OPAQUE_FRAME">
6224           Not a visible frame
6225         </error>
6226       </errors>
6227     </function>
6228   </category>
6229 
6230   <category id="breakpointCategory" label="Breakpoint">
6231 
6232     <intro>
6233     </intro>
6234 
6235     <function id="SetBreakpoint" num="38">
6236       <synopsis>Set Breakpoint</synopsis>
6237       <description>
6238         Set a breakpoint at the instruction indicated by
6239         <code>method</code> and <code>location</code>.
6240         An instruction can only have one breakpoint.
6241         <p/>
6242         Whenever the designated instruction is about to be executed, a
6243         <eventlink id="Breakpoint"></eventlink> event is generated.
6244       </description>
6245       <origin>jvmdi</origin>
6246       <capabilities>
6247         <required id="can_generate_breakpoint_events"></required>
6248       </capabilities>
6249       <parameters>
6250         <param id="klass">
6251           <jclass method="method"/>
6252             <description>
6253               The class in which to set the breakpoint
6254             </description>
6255         </param>
6256         <param id="method">
6257           <jmethodID class="klass"/>
6258             <description>
6259               The method in which to set the breakpoint
6260             </description>
6261         </param>
6262         <param id="location">
6263           <jlocation/>
6264           <description>
6265             the index of the instruction at which to set the breakpoint
6266 
6267           </description>
6268         </param>
6269       </parameters>
6270       <errors>
6271         <error id="JVMTI_ERROR_DUPLICATE">
6272           The designated bytecode already has a breakpoint.
6273         </error>
6274       </errors>
6275     </function>
6276 
6277     <function id="ClearBreakpoint" num="39">
6278       <synopsis>Clear Breakpoint</synopsis>
6279       <description>
6280         Clear the breakpoint at the bytecode indicated by
6281         <code>method</code> and <code>location</code>.
6282       </description>
6283       <origin>jvmdi</origin>
6284       <capabilities>
6285         <required id="can_generate_breakpoint_events"></required>
6286       </capabilities>
6287       <parameters>
6288         <param id="klass">
6289           <jclass method="method"/>
6290             <description>
6291               The class in which to clear the breakpoint
6292             </description>
6293         </param>
6294         <param id="method">
6295           <jmethodID class="klass"/>
6296             <description>
6297               The method in which to clear the breakpoint
6298             </description>
6299         </param>
6300         <param id="location">
6301           <jlocation/>
6302           <description>
6303             the index of the instruction at which to clear the breakpoint
6304           </description>
6305         </param>
6306       </parameters>
6307       <errors>
6308         <error id="JVMTI_ERROR_NOT_FOUND">
6309           There's no breakpoint at the designated bytecode.
6310         </error>
6311       </errors>
6312     </function>
6313 
6314   </category>
6315 
6316   <category id="fieldWatch" label="Watched Field">
6317 
6318     <intro>
6319     </intro>
6320 
6321     <function id="SetFieldAccessWatch" num="41">
6322       <synopsis>Set Field Access Watch</synopsis>
6323       <description>
6324         Generate a <eventlink id="FieldAccess"></eventlink> event
6325         when the field specified
6326         by <code>klass</code> and
6327         <code>field</code> is about to be accessed.
6328         An event will be generated for each access of the field
6329         until it is canceled with
6330         <functionlink id="ClearFieldAccessWatch"></functionlink>.
6331         Field accesses from Java programming language code or from JNI code are watched,
6332         fields modified by other means are not watched.
6333         Note that <jvmti/> users should be aware that their own field accesses
6334         will trigger the watch.
6335         A field can only have one field access watch set.
6336         Modification of a field is not considered an access--use
6337         <functionlink id="SetFieldModificationWatch"></functionlink>
6338         to monitor modifications.
6339       </description>
6340       <origin>jvmdi</origin>
6341       <capabilities>
6342         <required id="can_generate_field_access_events"></required>
6343       </capabilities>
6344       <parameters>
6345         <param id="klass">
6346           <jclass field="field"/>
6347             <description>
6348               The class containing the field to watch
6349             </description>
6350         </param>
6351         <param id="field">
6352           <jfieldID class="klass"/>
6353             <description>
6354               The field to watch
6355 
6356             </description>
6357         </param>
6358       </parameters>
6359       <errors>
6360         <error id="JVMTI_ERROR_DUPLICATE">
6361           The designated field is already being watched for accesses.
6362         </error>
6363       </errors>
6364     </function>
6365 
6366     <function id="ClearFieldAccessWatch" num="42">
6367       <synopsis>Clear Field Access Watch</synopsis>
6368       <description>
6369         Cancel a field access watch previously set by
6370         <functionlink id="SetFieldAccessWatch"></functionlink>, on the
6371         field specified
6372         by <code>klass</code> and
6373         <code>field</code>.
6374       </description>
6375       <origin>jvmdi</origin>
6376       <capabilities>
6377         <required id="can_generate_field_access_events"></required>
6378       </capabilities>
6379       <parameters>
6380         <param id="klass">
6381           <jclass field="field"/>
6382             <description>
6383               The class containing the field to watch
6384             </description>
6385         </param>
6386         <param id="field">
6387           <jfieldID class="klass"/>
6388             <description>
6389               The field to watch
6390 
6391             </description>
6392         </param>
6393       </parameters>
6394       <errors>
6395         <error id="JVMTI_ERROR_NOT_FOUND">
6396           The designated field is not being watched for accesses.
6397         </error>
6398       </errors>
6399     </function>
6400 
6401     <function id="SetFieldModificationWatch" num="43">
6402       <synopsis>Set Field Modification Watch</synopsis>
6403       <description>
6404         Generate a <eventlink id="FieldModification"></eventlink> event
6405         when the field specified
6406         by <code>klass</code> and
6407         <code>field</code> is about to be modified.
6408         An event will be generated for each modification of the field
6409         until it is canceled with
6410         <functionlink id="ClearFieldModificationWatch"></functionlink>.
6411         Field modifications from Java programming language code or from JNI code are watched,
6412         fields modified by other means are not watched.
6413         Note that <jvmti/> users should be aware that their own field modifications
6414         will trigger the watch.
6415         A field can only have one field modification watch set.
6416       </description>
6417       <origin>jvmdi</origin>
6418       <capabilities>
6419         <required id="can_generate_field_modification_events"></required>
6420       </capabilities>
6421       <parameters>
6422         <param id="klass">
6423           <jclass field="field"/>
6424             <description>
6425               The class containing the field to watch
6426             </description>
6427         </param>
6428         <param id="field">
6429           <jfieldID class="klass"/>
6430             <description>
6431               The field to watch
6432 
6433             </description>
6434         </param>
6435       </parameters>
6436       <errors>
6437         <error id="JVMTI_ERROR_DUPLICATE">
6438           The designated field is already being watched for modifications.
6439         </error>
6440       </errors>
6441     </function>
6442 
6443     <function id="ClearFieldModificationWatch" num="44">
6444       <synopsis>Clear Field Modification Watch</synopsis>
6445       <description>
6446 
6447         Cancel a field modification watch previously set by
6448         <functionlink id="SetFieldModificationWatch"></functionlink>, on the
6449         field specified
6450         by <code>klass</code> and
6451         <code>field</code>.
6452       </description>
6453       <origin>jvmdi</origin>
6454       <capabilities>
6455         <required id="can_generate_field_modification_events"></required>
6456       </capabilities>
6457       <parameters>
6458         <param id="klass">
6459           <jclass field="field"/>
6460             <description>
6461               The class containing the field to watch
6462             </description>
6463         </param>
6464         <param id="field">
6465           <jfieldID class="klass"/>
6466             <description>
6467               The field to watch
6468 
6469             </description>
6470         </param>
6471       </parameters>
6472       <errors>
6473         <error id="JVMTI_ERROR_NOT_FOUND">
6474           The designated field is not being watched for modifications.
6475         </error>
6476       </errors>
6477     </function>
6478   </category>
6479 
6480   <category id="module" label="Module">
6481 
6482     <intro>
6483     </intro>
6484 
6485     <function id="GetAllModules" num="3" since="9">
6486       <synopsis>Get All Modules</synopsis>
6487       <description>
6488         Return an array of all modules loaded in the virtual machine.
6489         The array includes the unnamed module for each class loader.
6490         The number of modules in the array is returned via
6491         <code>module_count_ptr</code>, and the array itself via
6492         <code>modules_ptr</code>.
6493         <p/>
6494       </description>
6495       <origin>new</origin>
6496       <capabilities>
6497       </capabilities>
6498       <parameters>
6499         <param id="module_count_ptr">
6500           <outptr><jint/></outptr>
6501           <description>
6502             On return, points to the number of returned modules.
6503           </description>
6504         </param>
6505         <param id="modules_ptr">
6506           <allocbuf outcount="module_count_ptr"><jobject/></allocbuf>
6507             <description>
6508               On return, points to an array of references, one
6509               for each module.
6510             </description>
6511         </param>
6512       </parameters>
6513       <errors>
6514       </errors>
6515     </function>
6516 
6517     <function id="GetNamedModule" num="40" since="9">
6518       <synopsis>Get Named Module</synopsis>
6519       <description>
6520         Return the <code>java.lang.Module</code> object for a named
6521         module defined to a class loader that contains a given package.
6522         The module is returned via <code>module_ptr</code>.
6523         <p/>
6524         If a named module is defined to the class loader and it
6525         contains the package then that named module is returned,
6526         otherwise <code>NULL</code> is returned.
6527         <p/>
6528       </description>
6529       <origin>new</origin>
6530       <capabilities>
6531       </capabilities>
6532       <parameters>
6533         <param id="class_loader">
6534           <ptrtype>
6535             <jobject/>
6536             <nullok>the bootstrap loader is assumed</nullok>
6537           </ptrtype>
6538           <description>
6539             A class loader.
6540             If the <code>class_loader</code> is not <code>NULL</code>
6541             or a subclass of <code>java.lang.ClassLoader</code>
6542             this function returns
6543             <errorlink id="JVMTI_ERROR_ILLEGAL_ARGUMENT"></errorlink>.
6544           </description>
6545         </param>
6546         <param id="package_name">
6547           <inbuf><char/></inbuf>
6548           <description>
6549             The name of the package, encoded as a
6550             <internallink id="mUTF">modified UTF-8</internallink> string.
6551             The package name is in internal form (JVMS 4.2.1);
6552             identifiers are separated by forward slashes rather than periods.
6553           </description>
6554         </param>
6555         <param id="module_ptr">
6556           <outptr><jobject/></outptr>
6557           <description>
6558             On return, points to a <code>java.lang.Module</code> object
6559             or points to <code>NULL</code>.
6560           </description>
6561         </param>
6562       </parameters>
6563       <errors>
6564         <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
6565           If class loader is not <code>NULL</code> and is not a class loader object.
6566         </error>
6567       </errors>
6568     </function>
6569 
6570     <function id="AddModuleReads" num="94" since="9">
6571       <synopsis>Add Module Reads</synopsis>
6572       <description>
6573          Update a module to read another module. This function is a no-op
6574          when <paramlink id="module"></paramlink> is an unnamed module.
6575          This function facilitates the instrumentation of code
6576          in named modules where that instrumentation requires
6577          expanding the set of modules that a module reads.
6578       </description>
6579       <origin>new</origin>
6580       <capabilities>
6581       </capabilities>
6582       <parameters>
6583         <param id="module">
6584           <ptrtype><jobject/></ptrtype>
6585           <description>
6586             The module to update.
6587           </description>
6588         </param>
6589         <param id="to_module">
6590           <ptrtype><jobject/></ptrtype>
6591           <description>
6592             The additional module to read.
6593           </description>
6594         </param>
6595       </parameters>
6596       <errors>
6597         <error id="JVMTI_ERROR_INVALID_MODULE">
6598           If <paramlink id="module"></paramlink> is not a module object.
6599         </error>
6600         <error id="JVMTI_ERROR_INVALID_MODULE">
6601           If <paramlink id="to_module"></paramlink> is not a module object.
6602         </error>
6603         <error id="JVMTI_ERROR_UNMODIFIABLE_MODULE">
6604           if the module cannot be modified.
6605           See <functionlink id="IsModifiableModule"/>.
6606         </error>
6607       </errors>
6608     </function>
6609 
6610     <function id="AddModuleExports" num="95" since="9">
6611       <synopsis>Add Module Exports</synopsis>
6612       <description>
6613          Update a module to export a package to another module.
6614          This function is a no-op when <paramlink id="module"></paramlink>
6615          is an unnamed module or an open module.
6616          This function facilitates the instrumentation of code
6617          in named modules where that instrumentation requires
6618          expanding the set of packages that a module exports.
6619       </description>
6620       <origin>new</origin>
6621       <capabilities>
6622       </capabilities>
6623       <parameters>
6624         <param id="module">
6625           <ptrtype><jobject/></ptrtype>
6626           <description>
6627             The module to update.
6628           </description>
6629         </param>
6630         <param id="pkg_name">
6631           <inbuf><char/></inbuf>
6632           <description>
6633             The exported package name.
6634           </description>
6635         </param>
6636         <param id="to_module">
6637           <ptrtype><jobject/></ptrtype>
6638           <description>
6639             The module the package is exported to.
6640             If the <code>to_module</code> is not a subclass of
6641             <code>java.lang.Module</code> this function returns
6642             <errorlink id="JVMTI_ERROR_INVALID_MODULE"></errorlink>.
6643           </description>
6644         </param>
6645       </parameters>
6646       <errors>
6647         <error id="JVMTI_ERROR_INVALID_MODULE">
6648           If <paramlink id="module"></paramlink> is not a module object.
6649         </error>
6650         <error id="JVMTI_ERROR_INVALID_MODULE">
6651           If <paramlink id="to_module"></paramlink> is not a module object.
6652         </error>
6653         <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
6654           If the package <paramlink id="pkg_name"></paramlink>
6655           does not belong to the module.
6656         </error>
6657         <error id="JVMTI_ERROR_UNMODIFIABLE_MODULE">
6658           if the module cannot be modified.
6659           See <functionlink id="IsModifiableModule"/>.
6660         </error>
6661       </errors>
6662     </function>
6663 
6664     <function id="AddModuleOpens" num="96" since="9">
6665       <synopsis>Add Module Opens</synopsis>
6666       <description>
6667          Update a module to open a package to another module.
6668          This function is a no-op when <paramlink id="module"></paramlink>
6669          is an unnamed module or an open module.
6670          This function facilitates the instrumentation of code
6671          in modules where that instrumentation requires
6672          expanding the set of packages that a module opens to
6673          other modules.
6674       </description>
6675       <origin>new</origin>
6676       <capabilities>
6677       </capabilities>
6678       <parameters>
6679         <param id="module">
6680           <ptrtype><jobject/></ptrtype>
6681           <description>
6682             The module to update.
6683           </description>
6684         </param>
6685         <param id="pkg_name">
6686           <inbuf><char/></inbuf>
6687           <description>
6688             The package name of the package to open.
6689           </description>
6690         </param>
6691         <param id="to_module">
6692           <ptrtype><jobject/></ptrtype>
6693           <description>
6694             The module with the package to open.
6695             If the <code>to_module</code> is not a subclass of
6696             <code>java.lang.Module</code> this function returns
6697             <errorlink id="JVMTI_ERROR_INVALID_MODULE"></errorlink>.
6698           </description>
6699         </param>
6700       </parameters>
6701       <errors>
6702         <error id="JVMTI_ERROR_INVALID_MODULE">
6703           If <paramlink id="module"></paramlink> is not a module object.
6704         </error>
6705         <error id="JVMTI_ERROR_INVALID_MODULE">
6706           If <paramlink id="to_module"></paramlink> is not a module object.
6707         </error>
6708         <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
6709           If the package <paramlink id="pkg_name"></paramlink>
6710           does not belong to the module.
6711         </error>
6712         <error id="JVMTI_ERROR_UNMODIFIABLE_MODULE">
6713           if the module cannot be modified.
6714           See <functionlink id="IsModifiableModule"/>.
6715         </error>
6716       </errors>
6717     </function>
6718 
6719     <function id="AddModuleUses" num="97" since="9">
6720       <synopsis>Add Module Uses</synopsis>
6721       <description>
6722          Updates a module to add a service to the set of services that
6723          a module uses. This function is a no-op when the module
6724          is an unnamed module.
6725          This function facilitates the instrumentation of code
6726          in named modules where that instrumentation requires
6727          expanding the set of services that a module is using.
6728       </description>
6729       <origin>new</origin>
6730       <capabilities>
6731       </capabilities>
6732       <parameters>
6733         <param id="module">
6734           <ptrtype><jobject/></ptrtype>
6735           <description>
6736             The module to update.
6737           </description>
6738         </param>
6739         <param id="service">
6740           <ptrtype><jclass/></ptrtype>
6741           <description>
6742             The service to use.
6743           </description>
6744         </param>
6745       </parameters>
6746       <errors>
6747         <error id="JVMTI_ERROR_INVALID_MODULE">
6748           If <paramlink id="module"></paramlink> is not a module object.
6749         </error>
6750         <error id="JVMTI_ERROR_INVALID_CLASS">
6751           If <paramlink id="service"></paramlink> is not a class object.
6752         </error>
6753         <error id="JVMTI_ERROR_UNMODIFIABLE_MODULE">
6754           if the module cannot be modified.
6755           See <functionlink id="IsModifiableModule"/>.
6756         </error>
6757       </errors>
6758     </function>
6759 
6760     <function id="AddModuleProvides" num="98" since="9">
6761       <synopsis>Add Module Provides</synopsis>
6762       <description>
6763          Updates a module to add a service to the set of services that
6764          a module provides. This function is a no-op when the module
6765          is an unnamed module.
6766          This function facilitates the instrumentation of code
6767          in named modules where that instrumentation requires
6768          changes to the services that are provided.
6769       </description>
6770       <origin>new</origin>
6771       <capabilities>
6772       </capabilities>
6773       <parameters>
6774         <param id="module">
6775           <ptrtype><jobject/></ptrtype>
6776           <description>
6777             The module to update.
6778           </description>
6779         </param>
6780         <param id="service">
6781           <ptrtype><jclass/></ptrtype>
6782           <description>
6783             The service to provide.
6784           </description>
6785         </param>
6786         <param id="impl_class">
6787           <ptrtype><jclass/></ptrtype>
6788           <description>
6789             The implementation class for the provided service.
6790           </description>
6791         </param>
6792       </parameters>
6793       <errors>
6794         <error id="JVMTI_ERROR_INVALID_MODULE">
6795           If <paramlink id="module"></paramlink> is not a module object.
6796         </error>
6797         <error id="JVMTI_ERROR_INVALID_CLASS">
6798           If <paramlink id="service"></paramlink> is not a class object.
6799         </error>
6800         <error id="JVMTI_ERROR_INVALID_CLASS">
6801           If <paramlink id="impl_class"></paramlink> is not a class object.
6802         </error>
6803         <error id="JVMTI_ERROR_UNMODIFIABLE_MODULE">
6804           if the module cannot be modified.
6805           See <functionlink id="IsModifiableModule"/>.
6806         </error>
6807       </errors>
6808     </function>
6809 
6810     <function id="IsModifiableModule" num="99" since="9">
6811       <synopsis>Is Modifiable Module</synopsis>
6812       <description>
6813         Determines whether a module is modifiable.
6814         If a module is modifiable then this module can be updated with
6815         <functionlink id="AddModuleReads"/>, <functionlink id="AddModuleExports"/>,
6816         <functionlink id="AddModuleOpens"/>, <functionlink id="AddModuleUses"/>,
6817         and <functionlink id="AddModuleProvides"/>. If a module is not modifiable
6818         then the module can not be updated with these functions. The result of
6819         this function is always <code>JNI_TRUE</code> when called to determine
6820         if an unnamed module is modifiable.
6821       </description>
6822       <origin>new</origin>
6823       <capabilities>
6824       </capabilities>
6825       <parameters>
6826         <param id="module">
6827           <ptrtype><jobject/></ptrtype>
6828           <description>
6829             The module to query.
6830           </description>
6831         </param>
6832         <param id="is_modifiable_module_ptr">
6833           <outptr><jboolean/></outptr>
6834           <description>
6835             On return, points to the boolean result of this function.
6836           </description>
6837         </param>
6838       </parameters>
6839       <errors>
6840         <error id="JVMTI_ERROR_INVALID_MODULE">
6841           If <paramlink id="module"></paramlink> is not a module object.
6842         </error>
6843       </errors>
6844     </function>
6845 
6846   </category>
6847 
6848   <category id="class" label="Class">
6849     <function id="GetLoadedClasses" jkernel="yes" num="78">
6850       <synopsis>Get Loaded Classes</synopsis>
6851       <description>
6852         Return an array of all classes loaded in the virtual machine.
6853         The number of classes in the array is returned via
6854         <code>class_count_ptr</code>, and the array itself via
6855         <code>classes_ptr</code>.
6856         <p/>
6857         A class or interface creation can be triggered by one of the following:
6858         <ul>
6859         <li>By loading and deriving a class from a <code>class</code> file representation
6860             using class loader (see <vmspec chapter="5.3"/>).</li>
6861         <li>By invoking <externallink id="../api/java.base/java/lang/invoke/MethodHandles.Lookup.html#defineHiddenClass(byte[],boolean,java.lang.invoke.MethodHandles.Lookup.ClassOption...)">Lookup::defineHiddenClass</externallink>
6862             that creates a hidden class or interface from a <code>class</code> file representation.</li>
6863         <li>By invoking methods in certain Java SE Platform API such as reflection.</li>
6864          </ul>
6865         <p/>
6866         An array class is created directly by Java virtual machine.  An array class
6867         creation can be triggered by using class loaders or by invoking methods in certain
6868         Java SE Platform API such as reflection.
6869         <p/>
6870         The returned list includes all classes and interfaces, including
6871         <externallink id="../api/java.base/java/lang/Class.html#isHidden()">
6872         hidden classes or interfaces</externallink>,
6873         and also array classes of all types
6874         (including arrays of primitive types).
6875         Primitive classes (for example, <code>java.lang.Integer.TYPE</code>) are
6876         <i>not</i> included in the returned list.
6877       </description>
6878       <origin>jvmdi</origin>
6879       <capabilities>
6880       </capabilities>
6881       <parameters>
6882         <param id="class_count_ptr">
6883           <outptr><jint/></outptr>
6884           <description>
6885             On return, points to the number of classes.
6886           </description>
6887         </param>
6888         <param id="classes_ptr">
6889           <allocbuf outcount="class_count_ptr"><jclass/></allocbuf>
6890             <description>
6891               On return, points to an array of references, one
6892               for each class.
6893             </description>
6894         </param>
6895       </parameters>
6896       <errors>
6897       </errors>
6898     </function>
6899 
6900     <function id="GetClassLoaderClasses" jkernel="yes" num="79">
6901       <synopsis>Get Classloader Classes</synopsis>
6902       <description>
6903         Returns an array of all classes which this class loader
6904         can find by name via 
6905         <externallink id="../api/java.base/java/lang/ClassLoader.html#loadClass(java.lang.String,boolean)">ClassLoader::loadClass</externallink>,
6906         <externallink id="../api/java.base/java/lang/Class.html#forName(java.lang.String,boolean,java.lang.ClassLoader)">Class::forName</externallink> and bytecode linkage.
6907         That is, <code>initiating_loader</code>
6908         has been recorded as an initiating loader of the returned classes.
6909         Each class in the returned array was created by this class loader,
6910         either by defining it directly or by delegation to another class loader.
6911         See <vmspec chapter="5.3"/>.
6912         <p/>
6913         The returned list does not include
6914         <externallink id="../api/java.base/java/lang/Class.html#isHidden()">hidden
6915         classes or interfaces</externallink> created by
6916         the invocation of <externallink id="../api/java.base/java/lang/invoke/MethodHandles.Lookup.html#defineHiddenClass(byte[],boolean,java.lang.invoke.MethodHandles.Lookup.ClassOption...)">Lookup::defineHiddenClass</externallink> because:
6917         <ul>
6918         <li>A hidden class or interface cannot be referenced by the constant pools
6919             of other classes and interfaces.</li>
6920         <li>A hidden class or interface cannot be discovered by any class loader
6921             including its defining loader.</li>
6922         </ul>
6923         In addition, the returned list does not include array classes whose
6924         element type is a hidden class or interface as they cannot be discovered
6925         by any class loader.
6926         <p/>
6927         The number of classes in the array is returned via
6928         <code>class_count_ptr</code>, and the array itself via
6929         <code>classes_ptr</code>.
6930       </description>
6931       <origin>jvmdi</origin>
6932       <capabilities>
6933       </capabilities>
6934       <parameters>
6935         <param id="initiating_loader">
6936           <ptrtype>
6937             <jobject/>
6938             <nullok>the classes initiated by the bootstrap loader will be returned</nullok>
6939           </ptrtype>
6940             <description>
6941               An initiating class loader.
6942             </description>
6943         </param>
6944         <param id="class_count_ptr">
6945           <outptr><jint/></outptr>
6946           <description>
6947             On return, points to the number of classes.
6948           </description>
6949         </param>
6950         <param id="classes_ptr">
6951           <allocbuf outcount="class_count_ptr"><jclass/></allocbuf>
6952             <description>
6953               On return, points to an array of references, one
6954               for each class.
6955             </description>
6956         </param>
6957       </parameters>
6958       <errors>
6959       </errors>
6960     </function>
6961 
6962     <function id="GetClassSignature" phase="start" num="48">
6963       <synopsis>Get Class Signature</synopsis>
6964       <description>
6965         Return the name and the generic signature of the class indicated by <code>klass</code>.
6966         <p/>
6967         If the class indicated by <code>klass</code> is a class or interface, then:
6968         <ul>
6969         <li>If the class or interface is not <externallink id="../api/java.base/java/lang/Class.html#isHidden()">hidden</externallink>,
6970           then the returned name is <externallink id="jni/types.html#type-signatures">
6971           JNI type signature</externallink>.
6972           For example, java.util.List is "Ljava/util/List;"
6973         </li>
6974         <li>If the class or interface is <externallink id="../api/java.base/java/lang/Class.html#isHidden()">hidden</externallink>,
6975           then the returned name is a string of the form:
6976           <code>"L" + N + ";" + "/" + S</code>
6977           where <code>N</code> is the binary name encoded in internal form
6978           indicated by the <code>class</code> file passed to
6979           <externallink id="../api/java.base/java/lang/invoke/MethodHandles.Lookup.html#defineHiddenClass(byte[],boolean,java.lang.invoke.MethodHandles.Lookup.ClassOption...)">Lookup::defineHiddenClass</externallink>,
6980           and <code>S</code> is an unqualified name.
6981           The returned name is not a valid type descriptor.
6982         </li>
6983         </ul>
6984         <p/>
6985         If the class indicated by <code>klass</code> represents an array class, then
6986         the returned name is a string consisting of one or more "<code>[</code>" characters
6987         representing the depth of the array nesting, followed by the class signature
6988         of the element type.  For example the class signature of java.lang.String[] is
6989         "[Ljava/lang/String;" and that of int[] is "[I".
6990         <p/>
6991         If the class indicated by <code>klass</code> represents primitive type or <code>void</code>,
6992         then the returned name is the <externallink id="jni/types.html#type-signatures">
6993         type signature character of the corresponding primitive type</externallink>.
6994         For example, java.lang.Integer.TYPE is "I".
6995       </description>
6996       <origin>jvmdiClone</origin>
6997       <capabilities>
6998       </capabilities>
6999       <parameters>
7000         <param id="klass">
7001           <jclass/>
7002             <description>
7003               The class to query.
7004             </description>
7005         </param>
7006         <param id="signature_ptr">
7007           <allocbuf>
7008             <char/>
7009             <nullok>the signature is not returned</nullok>
7010           </allocbuf>
7011           <description>
7012             On return, points to the JNI type signature of the class, encoded as a
7013             <internallink id="mUTF">modified UTF-8</internallink> string.
7014           </description>
7015         </param>
7016         <param id="generic_ptr">
7017           <allocbuf>
7018             <char/>
7019             <nullok>the generic signature is not returned</nullok>
7020           </allocbuf>
7021           <description>
7022             On return, points to the generic signature of the class, encoded as a
7023             <internallink id="mUTF">modified UTF-8</internallink> string.
7024             If there is no generic signature attribute for the class, then,
7025             on return, points to <code>NULL</code>.
7026           </description>
7027         </param>
7028       </parameters>
7029       <errors>
7030       </errors>
7031     </function>
7032 
7033     <function id="GetClassStatus" phase="start" num="49">
7034       <synopsis>Get Class Status</synopsis>
7035       <description>
7036         Get the status of the class. Zero or more of the following bits can be
7037         set.
7038         <constants id="jvmtiClassStatus" label="Class Status Flags" kind="bits">
7039           <constant id="JVMTI_CLASS_STATUS_VERIFIED" num="1">
7040             Class bytecodes have been verified
7041           </constant>
7042           <constant id="JVMTI_CLASS_STATUS_PREPARED" num="2">
7043             Class preparation is complete
7044           </constant>
7045           <constant id="JVMTI_CLASS_STATUS_INITIALIZED" num="4">
7046             Class initialization is complete. Static initializer has been run.
7047           </constant>
7048           <constant id="JVMTI_CLASS_STATUS_ERROR" num="8">
7049             Error during initialization makes class unusable
7050           </constant>
7051           <constant id="JVMTI_CLASS_STATUS_ARRAY" num="16">
7052             Class is an array.  If set, all other bits are zero.
7053           </constant>
7054           <constant id="JVMTI_CLASS_STATUS_PRIMITIVE" num="32">
7055             Class is a primitive class (for example, <code>java.lang.Integer.TYPE</code>).
7056             If set, all other bits are zero.
7057           </constant>
7058         </constants>
7059       </description>
7060       <origin>jvmdi</origin>
7061       <capabilities>
7062       </capabilities>
7063       <parameters>
7064         <param id="klass">
7065           <jclass/>
7066             <description>
7067               The class to query.
7068             </description>
7069         </param>
7070         <param id="status_ptr">
7071           <outptr><jint/></outptr>
7072           <description>
7073             On return, points to the current state of this class as one or
7074             more of the <internallink id="jvmtiClassStatus">class status flags</internallink>.
7075           </description>
7076         </param>
7077       </parameters>
7078       <errors>
7079       </errors>
7080     </function>
7081 
7082     <function id="GetSourceFileName" phase="start" num="50">
7083       <synopsis>Get Source File Name</synopsis>
7084       <description>
7085         For the class indicated by <code>klass</code>, return the source file
7086         name via <code>source_name_ptr</code>. The returned string
7087         is a file name only and never contains a directory name.
7088         <p/>
7089         For primitive classes (for example, <code>java.lang.Integer.TYPE</code>)
7090         and for arrays this function returns
7091         <errorlink id="JVMTI_ERROR_ABSENT_INFORMATION"></errorlink>.
7092       </description>
7093       <origin>jvmdi</origin>
7094       <capabilities>
7095         <required id="can_get_source_file_name"></required>
7096       </capabilities>
7097       <parameters>
7098         <param id="klass">
7099           <jclass/>
7100             <description>
7101               The class to query.
7102             </description>
7103         </param>
7104         <param id="source_name_ptr">
7105           <allocbuf><char/></allocbuf>
7106           <description>
7107             On return, points to the class's source file name, encoded as a
7108             <internallink id="mUTF">modified UTF-8</internallink> string.
7109           </description>
7110         </param>
7111       </parameters>
7112       <errors>
7113         <error id="JVMTI_ERROR_ABSENT_INFORMATION">
7114           Class information does not include a source file name. This includes
7115           cases where the class is an array class or primitive class.
7116         </error>
7117       </errors>
7118     </function>
7119 
7120     <function id="GetClassModifiers" phase="start" num="51">
7121       <synopsis>Get Class Modifiers</synopsis>
7122       <description>
7123         For the class indicated by <code>klass</code>, return the access
7124         flags
7125         via <code>modifiers_ptr</code>.
7126         Access flags are defined in <vmspec chapter="4"/>.
7127         <p/>
7128         If the class is an array class, then its public, private, and protected
7129         modifiers are the same as those of its component type. For arrays of
7130         primitives, this component type is represented by one of the primitive
7131         classes (for example, <code>java.lang.Integer.TYPE</code>).
7132         <p/>
7133         If the class is a primitive class, its public modifier is always true,
7134         and its protected and private modifiers are always false.
7135         <p/>
7136         If the class is an array class or a primitive class then its final
7137         modifier is always true and its interface modifier is always false.
7138         The values of its other modifiers are not determined by this specification.
7139 
7140       </description>
7141       <origin>jvmdi</origin>
7142       <capabilities>
7143       </capabilities>
7144       <parameters>
7145         <param id="klass">
7146           <jclass/>
7147             <description>
7148               The class to query.
7149             </description>
7150         </param>
7151         <param id="modifiers_ptr">
7152           <outptr><jint/></outptr>
7153           <description>
7154             On return, points to the current access flags of this class.
7155 
7156           </description>
7157         </param>
7158       </parameters>
7159       <errors>
7160       </errors>
7161     </function>
7162 
7163     <function id="GetClassMethods" phase="start" num="52">
7164       <synopsis>Get Class Methods</synopsis>
7165       <description>
7166         For the class indicated by <code>klass</code>, return a count of
7167         methods via <code>method_count_ptr</code> and a list of
7168         method IDs via <code>methods_ptr</code>. The method list contains
7169         constructors and static initializers as well as true methods.
7170         Only directly declared methods are returned (not inherited methods).
7171         An empty method list is returned for array classes and primitive classes
7172         (for example, <code>java.lang.Integer.TYPE</code>).
7173       </description>
7174       <origin>jvmdi</origin>
7175       <capabilities>
7176         <capability id="can_maintain_original_method_order"/>
7177       </capabilities>
7178       <parameters>
7179         <param id="klass">
7180           <jclass/>
7181             <description>
7182               The class to query.
7183             </description>
7184         </param>
7185         <param id="method_count_ptr">
7186           <outptr><jint/></outptr>
7187           <description>
7188             On return, points to the number of methods declared in this class.
7189           </description>
7190         </param>
7191         <param id="methods_ptr">
7192           <allocbuf outcount="method_count_ptr"><jmethodID class="klass"/></allocbuf>
7193             <description>
7194               On return, points to the method ID array.
7195             </description>
7196         </param>
7197       </parameters>
7198       <errors>
7199         <error id="JVMTI_ERROR_CLASS_NOT_PREPARED">
7200           <paramlink id="klass"></paramlink> is not prepared.
7201         </error>
7202       </errors>
7203     </function>
7204 
7205     <function id="GetClassFields" phase="start" num="53">
7206       <synopsis>Get Class Fields</synopsis>
7207       <description>
7208         For the class indicated by <code>klass</code>, return a count of fields
7209         via <code>field_count_ptr</code> and a list of field IDs via
7210         <code>fields_ptr</code>.
7211         Only directly declared fields are returned (not inherited fields).
7212         Fields are returned in the order they occur in the class file.
7213         An empty field list is returned for array classes and primitive classes
7214         (for example, <code>java.lang.Integer.TYPE</code>).
7215         Use JNI to determine the length of an array.
7216       </description>
7217       <origin>jvmdi</origin>
7218       <capabilities>
7219       </capabilities>
7220       <parameters>
7221         <param id="klass">
7222           <jclass/>
7223             <description>
7224               The class to query.
7225             </description>
7226         </param>
7227         <param id="field_count_ptr">
7228           <outptr><jint/></outptr>
7229           <description>
7230             On return, points to the number of fields declared in this class.
7231           </description>
7232         </param>
7233         <param id="fields_ptr">
7234           <allocbuf outcount="field_count_ptr"><jfieldID/></allocbuf>
7235             <description>
7236               On return, points to the field ID array.
7237             </description>
7238         </param>
7239       </parameters>
7240       <errors>
7241         <error id="JVMTI_ERROR_CLASS_NOT_PREPARED">
7242           <paramlink id="klass"></paramlink> is not prepared.
7243         </error>
7244       </errors>
7245     </function>
7246 
7247     <function id="GetImplementedInterfaces" phase="start" num="54">
7248       <synopsis>Get Implemented Interfaces</synopsis>
7249       <description>
7250         Return the direct super-interfaces of this class. For a class, this
7251         function returns the interfaces declared in its <code>implements</code>
7252         clause. For an interface, this function returns the interfaces declared in
7253         its <code>extends</code> clause.
7254         An empty interface list is returned for array classes and primitive classes
7255         (for example, <code>java.lang.Integer.TYPE</code>).
7256       </description>
7257       <origin>jvmdi</origin>
7258       <capabilities>
7259       </capabilities>
7260       <parameters>
7261         <param id="klass">
7262           <jclass/>
7263             <description>
7264               The class to query.
7265             </description>
7266         </param>
7267         <param id="interface_count_ptr">
7268           <outptr><jint/></outptr>
7269           <description>
7270             On return, points to the number of interfaces.
7271           </description>
7272         </param>
7273         <param id="interfaces_ptr">
7274           <allocbuf outcount="interface_count_ptr"><jclass/></allocbuf>
7275             <description>
7276               On return, points to the interface array.
7277             </description>
7278         </param>
7279       </parameters>
7280       <errors>
7281         <error id="JVMTI_ERROR_CLASS_NOT_PREPARED">
7282           <paramlink id="klass"></paramlink> is not prepared.
7283         </error>
7284       </errors>
7285     </function>
7286 
7287     <function id="GetClassVersionNumbers" phase="start" num="145" since="1.1">
7288       <synopsis>Get Class Version Numbers</synopsis>
7289       <description>
7290         For the class indicated by <code>klass</code>,
7291         return the minor and major version numbers,
7292         as defined in
7293         <vmspec chapter="4"/>.
7294       </description>
7295       <origin>new</origin>
7296       <capabilities>
7297       </capabilities>
7298       <parameters>
7299         <param id="klass">
7300           <jclass/>
7301             <description>
7302               The class to query.
7303             </description>
7304         </param>
7305         <param id="minor_version_ptr">
7306           <outptr><jint/></outptr>
7307           <description>
7308             On return, points to the value of the
7309             <code>minor_version</code> item of the
7310             Class File Format.
7311             Note: to be consistent with the Class File Format,
7312             the minor version number is the first parameter.
7313           </description>
7314         </param>
7315         <param id="major_version_ptr">
7316           <outptr><jint/></outptr>
7317           <description>
7318             On return, points to the value of the
7319             <code>major_version</code> item of the
7320             Class File Format.
7321           </description>
7322         </param>
7323       </parameters>
7324       <errors>
7325         <error id="JVMTI_ERROR_ABSENT_INFORMATION">
7326           The class is a primitive or array class.
7327         </error>
7328       </errors>
7329     </function>
7330 
7331     <function id="GetConstantPool" phase="start" num="146" since="1.1">
7332       <synopsis>Get Constant Pool</synopsis>
7333       <description>
7334         For the class indicated by <code>klass</code>,
7335         return the raw bytes of the constant pool in the format of the
7336         <code>constant_pool</code> item of
7337         <vmspec chapter="4"/>.
7338         The format of the constant pool may differ between versions
7339         of the Class File Format, so, the
7340         <functionlink id="GetClassVersionNumbers">minor and major
7341         class version numbers</functionlink> should be checked for
7342         compatibility.
7343         <p/>
7344         The returned constant pool might not have the same layout or
7345         contents as the constant pool in the defining class file.
7346         The constant pool returned by GetConstantPool() may have
7347         more or fewer entries than the defining constant pool.
7348         Entries may be in a different order.
7349         The constant pool returned by GetConstantPool() will match the
7350         constant pool used by
7351         <functionlink id="GetBytecodes">GetBytecodes()</functionlink>.
7352         That is, the bytecodes returned by GetBytecodes() will have
7353         constant pool indices which refer to constant pool entries returned
7354         by GetConstantPool().
7355         Note that since <functionlink id="RetransformClasses"/>
7356         and <functionlink id="RedefineClasses"/> can change
7357         the constant pool, the constant pool returned by this function
7358         can change accordingly.  Thus, the correspondence between
7359         GetConstantPool() and GetBytecodes() does not hold if there
7360         is an intervening class retransformation or redefinition.
7361         The value of a constant pool entry used by a given bytecode will
7362         match that of the defining class file (even if the indices don't match).
7363         Constant pool entries which are not used directly or indirectly by
7364         bytecodes (for example,  UTF-8 strings associated with annotations) are
7365         not  required to exist in the returned constant pool.
7366       </description>
7367       <origin>new</origin>
7368       <capabilities>
7369         <required id="can_get_constant_pool"></required>
7370       </capabilities>
7371       <parameters>
7372         <param id="klass">
7373           <jclass/>
7374             <description>
7375               The class to query.
7376             </description>
7377         </param>
7378         <param id="constant_pool_count_ptr">
7379           <outptr><jint/></outptr>
7380           <description>
7381             On return, points to the number of entries
7382             in the constant pool table plus one.
7383             This corresponds to the <code>constant_pool_count</code>
7384             item of the Class File Format.
7385           </description>
7386         </param>
7387         <param id="constant_pool_byte_count_ptr">
7388           <outptr><jint/></outptr>
7389           <description>
7390             On return, points to the number of bytes
7391             in the returned raw constant pool.
7392           </description>
7393         </param>
7394         <param id="constant_pool_bytes_ptr">
7395           <allocbuf outcount="constant_pool_byte_count_ptr"><uchar/></allocbuf>
7396             <description>
7397               On return, points to the raw constant pool, that is the bytes
7398               defined by the <code>constant_pool</code> item of the
7399               Class File Format
7400             </description>
7401         </param>
7402       </parameters>
7403       <errors>
7404         <error id="JVMTI_ERROR_ABSENT_INFORMATION">
7405           The class is a primitive or array class.
7406         </error>
7407       </errors>
7408     </function>
7409 
7410     <function id="IsInterface" phase="start" num="55">
7411       <synopsis>Is Interface</synopsis>
7412       <description>
7413         Determines whether a class object reference represents an interface.
7414         The <code>jboolean</code> result is
7415         <code>JNI_TRUE</code> if the "class" is actually an interface,
7416         <code>JNI_FALSE</code> otherwise.
7417       </description>
7418       <origin>jvmdi</origin>
7419       <capabilities>
7420       </capabilities>
7421       <parameters>
7422         <param id="klass">
7423           <jclass/>
7424             <description>
7425               The class to query.
7426             </description>
7427         </param>
7428         <param id="is_interface_ptr">
7429           <outptr><jboolean/></outptr>
7430           <description>
7431             On return, points to the boolean result of this function.
7432 
7433           </description>
7434         </param>
7435       </parameters>
7436       <errors>
7437       </errors>
7438     </function>
7439 
7440     <function id="IsArrayClass" phase="start" num="56">
7441       <synopsis>Is Array Class</synopsis>
7442       <description>
7443         Determines whether a class object reference represents an array.
7444         The <code>jboolean</code> result is
7445         <code>JNI_TRUE</code> if the class is an array,
7446         <code>JNI_FALSE</code> otherwise.
7447       </description>
7448       <origin>jvmdi</origin>
7449       <capabilities>
7450       </capabilities>
7451       <parameters>
7452         <param id="klass">
7453           <jclass/>
7454             <description>
7455               The class to query.
7456             </description>
7457         </param>
7458         <param id="is_array_class_ptr">
7459           <outptr><jboolean/></outptr>
7460           <description>
7461             On return, points to the boolean result of this function.
7462 
7463           </description>
7464         </param>
7465       </parameters>
7466       <errors>
7467       </errors>
7468     </function>
7469 
7470     <function id="IsModifiableClass" jkernel="yes" phase="start" num="45" since="1.1">
7471       <synopsis>Is Modifiable Class</synopsis>
7472       <description>
7473         Determines whether a class is modifiable.
7474         If a class is modifiable (<paramlink id="is_modifiable_class_ptr"/>
7475         returns <code>JNI_TRUE</code>) the class can be
7476         redefined with <functionlink id="RedefineClasses"/> (assuming
7477         the agent possesses the
7478         <fieldlink id="can_redefine_classes" struct="jvmtiCapabilities"/>
7479         capability) or
7480         retransformed with <functionlink id="RetransformClasses"/> (assuming
7481         the agent possesses the
7482         <fieldlink id="can_retransform_classes" struct="jvmtiCapabilities"/>
7483         capability).
7484         If a class is not modifiable (<paramlink id="is_modifiable_class_ptr"/>
7485         returns <code>JNI_FALSE</code>) the class can be neither
7486         redefined nor retransformed.
7487         <p/>
7488         Primitive classes (for example, <code>java.lang.Integer.TYPE</code>),
7489         array classes, and some implementation defined classes are never modifiable.
7490         <p/>
7491       </description>
7492       <origin>new</origin>
7493       <capabilities>
7494         <capability id="can_redefine_any_class">
7495           If possessed then all classes (except primitive, array, and some implementation defined
7496           classes) are modifiable with <functionlink id="RedefineClasses"/>.
7497         </capability>
7498         <capability id="can_retransform_any_class">
7499           If possessed then all classes (except primitive, array, and some implementation defined
7500           classes) are modifiable with <functionlink id="RetransformClasses"/>.
7501         </capability>
7502         <capability id="can_redefine_classes">
7503           No effect on the result of the function.
7504           But must additionally be possessed to modify the class with
7505           <functionlink id="RedefineClasses"/>.
7506         </capability>
7507         <capability id="can_retransform_classes">
7508           No effect on the result of the function.
7509           But must additionally be possessed to modify the class with
7510           <functionlink id="RetransformClasses"/>.
7511         </capability>
7512       </capabilities>
7513       <parameters>
7514         <param id="klass">
7515           <jclass/>
7516             <description>
7517               The class to query.
7518             </description>
7519         </param>
7520         <param id="is_modifiable_class_ptr">
7521           <outptr><jboolean/></outptr>
7522           <description>
7523             On return, points to the boolean result of this function.
7524           </description>
7525         </param>
7526       </parameters>
7527       <errors>
7528       </errors>
7529     </function>
7530 
7531     <function id="GetClassLoader" phase="start" num="57">
7532       <synopsis>Get Class Loader</synopsis>
7533       <description>
7534         For the class indicated by <code>klass</code>, return via
7535         <code>classloader_ptr</code> a reference to the class loader for the
7536         class.
7537       </description>
7538       <origin>jvmdi</origin>
7539       <capabilities>
7540       </capabilities>
7541       <parameters>
7542         <param id="klass">
7543           <jclass/>
7544             <description>
7545               The class to query.
7546             </description>
7547         </param>
7548         <param id="classloader_ptr">
7549           <outptr><jobject/></outptr>
7550             <description>
7551               On return, points to the class loader that loaded
7552               this class.
7553               If the class was not created by a class loader
7554               or if the class loader is the bootstrap class loader,
7555               points to <code>NULL</code>.
7556             </description>
7557         </param>
7558       </parameters>
7559       <errors>
7560       </errors>
7561 
7562     </function>
7563 
7564     <function id="GetSourceDebugExtension" phase="start" num="90">
7565       <synopsis>Get Source Debug Extension</synopsis>
7566       <description>
7567         For the class indicated by <code>klass</code>, return the debug
7568         extension via <code>source_debug_extension_ptr</code>.
7569         The returned string
7570         contains exactly the debug extension information present in the
7571         class file of <code>klass</code>.
7572       </description>
7573       <origin>jvmdi</origin>
7574       <capabilities>
7575         <required id="can_get_source_debug_extension"></required>
7576       </capabilities>
7577       <parameters>
7578         <param id="klass">
7579           <jclass/>
7580             <description>
7581               The class to query.
7582             </description>
7583         </param>
7584         <param id="source_debug_extension_ptr">
7585           <allocbuf><char/></allocbuf>
7586           <description>
7587             On return, points to the class's debug extension, encoded as a
7588             <internallink id="mUTF">modified UTF-8</internallink> string.
7589           </description>
7590         </param>
7591       </parameters>
7592       <errors>
7593         <error id="JVMTI_ERROR_ABSENT_INFORMATION">
7594           Class information does not include a debug extension.
7595         </error>
7596       </errors>
7597     </function>
7598 
7599     <function id="RetransformClasses" jkernel="yes" num="152" since="1.1">
7600       <synopsis>Retransform Classes</synopsis>
7601       <description>
7602         This function facilitates the
7603         <internallink id="bci">bytecode instrumentation</internallink>
7604         of already loaded classes.
7605         To replace the class definition without reference to the existing
7606         bytecodes, as one might do when recompiling from source for
7607         fix-and-continue debugging, <functionlink id="RedefineClasses"/>
7608         function should be used instead.
7609         <p/>
7610         When classes are initially loaded or when they are
7611         <functionlink id="RedefineClasses">redefined</functionlink>,
7612         the initial class file bytes can be transformed with the
7613         <eventlink id="ClassFileLoadHook"/> event.
7614         This function reruns the transformation process
7615         (whether or not a transformation has previously occurred).
7616         This retransformation follows these steps:
7617         <ul>
7618           <li>starting from the initial class file bytes
7619           </li>
7620           <li>for each <fieldlink id="can_retransform_classes"
7621                      struct="jvmtiCapabilities">retransformation
7622                                                 incapable</fieldlink>
7623             agent which received a
7624             <code>ClassFileLoadHook</code> event during the previous
7625             load or redefine, the bytes it returned
7626             (via the <code>new_class_data</code> parameter)
7627             are reused as the output of the transformation;
7628             note that this is equivalent to reapplying
7629             the previous transformation, unaltered. except that
7630             the <code>ClassFileLoadHook</code> event
7631             is <b>not</b> sent to these agents
7632           </li>
7633           <li>for each <fieldlink id="can_retransform_classes"
7634                      struct="jvmtiCapabilities">retransformation
7635                                                 capable</fieldlink>
7636             agent, the <code>ClassFileLoadHook</code> event is sent,
7637             allowing a new transformation to be applied
7638           </li>
7639           <li>the transformed class file bytes are installed as the new
7640             definition of the class
7641           </li>
7642         </ul>
7643         See the <eventlink id="ClassFileLoadHook"/> event for more details.
7644         <p/>
7645         The initial class file bytes represent the bytes passed to
7646         <code>ClassLoader.defineClass</code>
7647         or <code>RedefineClasses</code> (before any transformations
7648         were applied), however they may not exactly match them.
7649         The constant pool may differ in ways described in
7650         <functionlink id="GetConstantPool"/>.
7651         Constant pool indices in the bytecodes of methods will correspond.
7652         Some attributes may not be present.
7653         Where order is not meaningful, for example the order of methods,
7654         order may not be preserved.
7655         <p/>
7656         Retransformation can cause new versions of methods to be installed.
7657         Old method versions may become
7658         <internallink id="obsoleteMethods">obsolete</internallink>
7659         The new method version will be used on new invokes.
7660         If a method has active stack frames, those active frames continue to
7661         run the bytecodes of the original method version.
7662         <p/>
7663         This function does not cause any initialization except that which
7664         would occur under the customary JVM semantics.
7665         In other words, retransforming a class does not cause its initializers to be
7666         run. The values of static fields will remain as they were
7667         prior to the call.
7668         <p/>
7669         Threads need not be suspended.
7670         <p/>
7671         All breakpoints in the class are cleared.
7672         <p/>
7673         All attributes are updated.
7674         <p/>
7675         Instances of the retransformed class are not affected -- fields retain their
7676         previous values.
7677         <functionlink id="GetTag">Tags</functionlink> on the instances are
7678         also unaffected.
7679         <p/>
7680         In response to this call, no events other than the
7681         <eventlink id="ClassFileLoadHook"/> event
7682         will be sent.
7683         <p/>
7684         The retransformation may change method bodies, the constant pool and attributes
7685         (unless explicitly prohibited).
7686         The retransformation must not add, remove or rename fields or methods, change the
7687         signatures of methods, change modifiers, or change inheritance.
7688         The retransformation must not change the <code>NestHost</code>,
7689         <code>NestMembers</code>, or <code>Record</code> attributes.
7690         These restrictions may be lifted in future versions.
7691         See the error return description below for information on error codes
7692         returned if an unsupported retransformation is attempted.
7693         The class file bytes are not verified or installed until they have passed
7694         through the chain of <eventlink id="ClassFileLoadHook"/> events, thus the
7695         returned error code reflects the result of the transformations.
7696         If any error code is returned other than <code>JVMTI_ERROR_NONE</code>,
7697         none of the classes to be retransformed will have a new definition installed.
7698         When this function returns (with the error code of <code>JVMTI_ERROR_NONE</code>)
7699         all of the classes to be retransformed will have their new definitions installed.
7700       </description>
7701       <origin>new</origin>
7702       <capabilities>
7703         <required id="can_retransform_classes"></required>
7704         <capability id="can_retransform_any_class"></capability>
7705       </capabilities>
7706       <parameters>
7707         <param id="class_count">
7708           <jint min="0"/>
7709           <description>
7710             The number of classes to be retransformed.
7711           </description>
7712         </param>
7713         <param id="classes">
7714           <inbuf incount="class_count"><jclass/></inbuf>
7715           <description>
7716             The array of classes to be retransformed.
7717           </description>
7718         </param>
7719       </parameters>
7720       <errors>
7721         <error id="JVMTI_ERROR_UNMODIFIABLE_CLASS">
7722           One of the <paramlink id="classes"/> cannot be modified.
7723           See <functionlink id="IsModifiableClass"/>.
7724         </error>
7725         <error id="JVMTI_ERROR_INVALID_CLASS">
7726           One of the <paramlink id="classes"/> is not a valid class.
7727         </error>
7728         <error id="JVMTI_ERROR_UNSUPPORTED_VERSION">
7729           A retransformed class file has a version number not supported by this VM.
7730         </error>
7731         <error id="JVMTI_ERROR_INVALID_CLASS_FORMAT">
7732           A retransformed class file is malformed (The VM would return a <code>ClassFormatError</code>).
7733         </error>
7734         <error id="JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION">
7735           The retransformed class file definitions would lead to a circular definition
7736           (the VM would return a <code>ClassCircularityError</code>).
7737         </error>
7738         <error id="JVMTI_ERROR_FAILS_VERIFICATION">
7739           The retransformed class file bytes fail verification.
7740         </error>
7741         <error id="JVMTI_ERROR_NAMES_DONT_MATCH">
7742           The class name defined in a retransformed class file is
7743           different from the name in the old class object.
7744         </error>
7745         <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED">
7746           A retransformed class file would require adding a method.
7747         </error>
7748         <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED">
7749           A retransformed class file changes a field.
7750         </error>
7751         <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED">
7752           A direct superclass is different for a retransformed class file,
7753           or the set of directly implemented
7754           interfaces is different.
7755         </error>
7756         <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED">
7757           A retransformed class file does not declare a method
7758           declared in the old class version.
7759         </error>
7760         <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED">
7761           A retransformed class file has unsupported differences in class attributes.
7762         </error>
7763         <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED">
7764           A retransformed class file has different class modifiers.
7765         </error>
7766         <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED">
7767           A method in the retransformed class file has different modifiers
7768           than its counterpart in the old class version.
7769         </error>
7770       </errors>
7771     </function>
7772 
7773     <function id="RedefineClasses" jkernel="yes" num="87">
7774       <synopsis>Redefine Classes</synopsis>
7775       <typedef id="jvmtiClassDefinition" label="Class redefinition description">
7776         <field id="klass">
7777           <jclass/>
7778             <description>
7779               Class object for this class
7780             </description>
7781         </field>
7782         <field id="class_byte_count">
7783           <jint/>
7784           <description>
7785             Number of bytes defining class (below)
7786           </description>
7787         </field>
7788         <field id="class_bytes">
7789           <inbuf incount="class_byte_count"><uchar/></inbuf>
7790           <description>
7791             Bytes defining class (in <vmspec chapter="4"/>)
7792           </description>
7793         </field>
7794       </typedef>
7795       <description>
7796         All classes given are redefined according to the definitions
7797         supplied.
7798         This function is used to replace the definition of a class
7799         with a new definition, as might be needed in fix-and-continue
7800         debugging.
7801         Where the existing class file bytes are to be transformed, for
7802         example in
7803         <internallink id="bci">bytecode instrumentation</internallink>,
7804         <functionlink id="RetransformClasses"/> should be used.
7805         <p/>
7806         Redefinition can cause new versions of methods to be installed.
7807         Old method versions may become
7808         <internallink id="obsoleteMethods">obsolete</internallink>
7809         The new method version will be used on new invokes.
7810         If a method has active stack frames, those active frames continue to
7811         run the bytecodes of the original method version.
7812         If resetting of stack frames is desired, use
7813         <functionlink id="PopFrame"></functionlink>
7814         to pop frames with obsolete method versions.
7815         <p/>
7816         This function does not cause any initialization except that which
7817         would occur under the customary JVM semantics.
7818         In other words, redefining a class does not cause its initializers to be
7819         run. The values of static fields will remain as they were
7820         prior to the call.
7821         <p/>
7822         Threads need not be suspended.
7823         <p/>
7824         All breakpoints in the class are cleared.
7825         <p/>
7826         All attributes are updated.
7827         <p/>
7828         Instances of the redefined class are not affected -- fields retain their
7829         previous values.
7830         <functionlink id="GetTag">Tags</functionlink> on the instances are
7831         also unaffected.
7832         <p/>
7833         In response to this call, the <jvmti/> event
7834         <eventlink id="ClassFileLoadHook">Class File Load Hook</eventlink>
7835         will be sent (if enabled), but no other <jvmti/> events will be sent.
7836         <p/>
7837         The redefinition may change method bodies, the constant pool and attributes
7838         (unless explicitly prohibited).
7839         The redefinition must not add, remove or rename fields or methods, change the
7840         signatures of methods, change modifiers, or change inheritance.
7841         The redefinition must not change the <code>NestHost</code>,
7842         <code>NestMembers</code>, or <code>Record</code> attributes.
7843         These restrictions may be lifted in future versions.
7844         See the error return description below for information on error codes
7845         returned if an unsupported redefinition is attempted.
7846         The class file bytes are not verified or installed until they have passed
7847         through the chain of <eventlink id="ClassFileLoadHook"/> events, thus the
7848         returned error code reflects the result of the transformations applied
7849         to the bytes passed into <paramlink id="class_definitions"/>.
7850         If any error code is returned other than <code>JVMTI_ERROR_NONE</code>,
7851         none of the classes to be redefined will have a new definition installed.
7852         When this function returns (with the error code of <code>JVMTI_ERROR_NONE</code>)
7853         all of the classes to be redefined will have their new definitions installed.
7854       </description>
7855       <origin>jvmdi</origin>
7856       <capabilities>
7857         <required id="can_redefine_classes"></required>
7858         <capability id="can_redefine_any_class"></capability>
7859       </capabilities>
7860       <parameters>
7861         <param id="class_count">
7862           <jint min="0"/>
7863           <description>
7864             The number of classes specified in <code>class_definitions</code>
7865           </description>
7866         </param>
7867         <param id="class_definitions">
7868           <inbuf incount="class_count"><struct>jvmtiClassDefinition</struct></inbuf>
7869           <description>
7870             The array of new class definitions
7871           </description>
7872         </param>
7873       </parameters>
7874       <errors>
7875         <error id="JVMTI_ERROR_NULL_POINTER">
7876           One of <code>class_bytes</code> is <code>NULL</code>.
7877         </error>
7878         <error id="JVMTI_ERROR_UNMODIFIABLE_CLASS">
7879           An element of <code>class_definitions</code> cannot be modified.
7880           See <functionlink id="IsModifiableClass"/>.
7881         </error>
7882         <error id="JVMTI_ERROR_INVALID_CLASS">
7883           An element of <code>class_definitions</code> is not a valid class.
7884         </error>
7885         <error id="JVMTI_ERROR_UNSUPPORTED_VERSION">
7886           A new class file has a version number not supported by this VM.
7887         </error>
7888         <error id="JVMTI_ERROR_INVALID_CLASS_FORMAT">
7889           A new class file is malformed (The VM would return a <code>ClassFormatError</code>).
7890         </error>
7891         <error id="JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION">
7892           The new class file definitions would lead to a circular definition
7893           (the VM would return a <code>ClassCircularityError</code>).
7894         </error>
7895         <error id="JVMTI_ERROR_FAILS_VERIFICATION">
7896           The class bytes fail verification.
7897         </error>
7898         <error id="JVMTI_ERROR_NAMES_DONT_MATCH">
7899           The class name defined in a new class file is
7900           different from the name in the old class object.
7901         </error>
7902         <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED">
7903           A new class file would require adding a method.
7904         </error>
7905         <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED">
7906           A new class version changes a field.
7907         </error>
7908         <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED">
7909           A direct superclass is different for a new class
7910           version, or the set of directly implemented
7911           interfaces is different.
7912         </error>
7913         <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED">
7914           A new class version does not declare a method
7915           declared in the old class version.
7916         </error>
7917         <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED">
7918           A new class version has unsupported differences in class attributes.
7919         </error>
7920         <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED">
7921           A new class version has different modifiers.
7922         </error>
7923         <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED">
7924           A method in the new class version has different modifiers
7925           than its counterpart in the old class version.
7926         </error>
7927         <error id="JVMTI_ERROR_UNMODIFIABLE_MODULE">
7928           A module cannot be modified.
7929           See <functionlink id="IsModifiableModule"/>.
7930         </error>
7931       </errors>
7932     </function>
7933 
7934   </category>
7935 
7936   <category id="object" label="Object">
7937 
7938     <function id="GetObjectSize" jkernel="yes" phase="start" num="154">
7939       <synopsis>Get Object Size</synopsis>
7940       <description>
7941         For the object indicated by <code>object</code>,
7942         return via <code>size_ptr</code> the size of the object.
7943         This size is an implementation-specific approximation of
7944         the amount of storage consumed by this object.
7945         It may include some or all of the object's overhead, and thus
7946         is useful for comparison within an implementation but not
7947         between implementations.
7948         The estimate may change during a single invocation of the JVM.
7949       </description>
7950       <origin>new</origin>
7951       <capabilities>
7952       </capabilities>
7953       <parameters>
7954         <param id="object">
7955           <jobject/>
7956             <description>
7957               The object to query.
7958             </description>
7959         </param>
7960         <param id="size_ptr">
7961           <outptr><jlong/></outptr>
7962           <description>
7963             On return, points to the object's size in bytes.
7964           </description>
7965         </param>
7966       </parameters>
7967       <errors>
7968       </errors>
7969     </function>
7970 
7971     <function id="GetObjectHashCode" phase="start" num="58">
7972       <synopsis>Get Object Hash Code</synopsis>
7973       <description>
7974         For the object indicated by <code>object</code>,
7975         return via <code>hash_code_ptr</code> a hash code.
7976         This hash code could be used to maintain a hash table of object references,
7977         however, on some implementations this can cause significant performance
7978         impacts--in most cases
7979         <internallink id="Heap">tags</internallink>
7980         will be a more efficient means of associating information with objects.
7981         This function guarantees
7982         the same hash code value for a particular object throughout its life
7983       </description>
7984       <origin>jvmdi</origin>
7985       <capabilities>
7986       </capabilities>
7987       <parameters>
7988         <param id="object">
7989           <jobject/>
7990             <description>
7991               The object to query.
7992             </description>
7993         </param>
7994         <param id="hash_code_ptr">
7995           <outptr><jint/></outptr>
7996           <description>
7997             On return, points to the object's hash code.
7998           </description>
7999         </param>
8000       </parameters>
8001       <errors>
8002       </errors>
8003     </function>
8004 
8005     <function id="GetObjectMonitorUsage" num="59">
8006       <synopsis>Get Object Monitor Usage</synopsis>
8007       <typedef id="jvmtiMonitorUsage" label="Object monitor usage information">
8008         <field id="owner">
8009           <jthread/>
8010             <description>
8011               The thread owning this monitor, or <code>NULL</code> if unused
8012             </description>
8013         </field>
8014         <field id="entry_count">
8015           <jint/>
8016           <description>
8017             The number of times the owning thread has entered the monitor
8018           </description>
8019         </field>
8020         <field id="waiter_count">
8021           <jint/>
8022           <description>
8023             The number of threads waiting to own this monitor
8024           </description>
8025         </field>
8026         <field id="waiters">
8027           <allocfieldbuf><jthread/></allocfieldbuf>
8028             <description>
8029               The <code>waiter_count</code> waiting threads
8030             </description>
8031         </field>
8032         <field id="notify_waiter_count">
8033           <jint/>
8034           <description>
8035             The number of threads waiting to be notified by this monitor
8036           </description>
8037         </field>
8038         <field id="notify_waiters">
8039           <allocfieldbuf><jthread/></allocfieldbuf>
8040             <description>
8041               The <code>notify_waiter_count</code> threads waiting to be notified
8042             </description>
8043         </field>
8044       </typedef>
8045       <description>
8046         Get information about the object's monitor.
8047         The fields of the <functionlink id="jvmtiMonitorUsage"></functionlink> structure
8048         are filled in with information about usage of the monitor.
8049           <todo>
8050             Decide and then clarify suspend requirements.
8051           </todo>
8052       </description>
8053       <origin>jvmdi</origin>
8054       <capabilities>
8055         <required id="can_get_monitor_info"></required>
8056       </capabilities>
8057       <parameters>
8058         <param id="object">
8059           <jobject/>
8060             <description>
8061               The object to query.
8062             </description>
8063         </param>
8064         <param id="info_ptr">
8065           <outptr><struct>jvmtiMonitorUsage</struct></outptr>
8066           <description>
8067             On return, filled with monitor information for the
8068             specified object.
8069           </description>
8070         </param>
8071       </parameters>
8072       <errors>
8073       </errors>
8074     </function>
8075 
8076     <elide>
8077     <function id="GetObjectMonitors" num="116">
8078       <synopsis>Get Object Monitors</synopsis>
8079       <description>
8080         Return the list of object monitors.
8081         <p/>
8082         Note: details about each monitor can be examined with
8083         <functionlink id="GetObjectMonitorUsage"></functionlink>.
8084       </description>
8085       <origin>new</origin>
8086       <capabilities>
8087         <required id="can_get_monitor_info"></required>
8088       </capabilities>
8089       <parameters>
8090         <param id="monitorCnt">
8091           <outptr><jint/></outptr>
8092           <description>
8093             On return, pointer to the number
8094             of monitors returned in <code>monitors_ptr</code>.
8095           </description>
8096         </param>
8097         <param id="monitors_ptr">
8098           <allocbuf outcount="monitorCnt"><jobject/></allocbuf>
8099             <description>
8100               On return, pointer to the monitor list.
8101             </description>
8102         </param>
8103       </parameters>
8104       <errors>
8105       </errors>
8106     </function>
8107     </elide>
8108 
8109   </category>
8110 
8111   <category id="fieldCategory" label="Field">
8112 
8113     <intro>
8114     </intro>
8115 
8116     <function id="GetFieldName" phase="start" num="60">
8117       <synopsis>Get Field Name (and Signature)</synopsis>
8118       <description>
8119         For the field indicated by <paramlink id="klass"/> and <paramlink id="field"/>,
8120         return the field name via <paramlink id="name_ptr"/> and field signature via
8121         <paramlink id="signature_ptr"/>.
8122         <p/>
8123         Field signatures are defined in the
8124         <externallink id="jni/index.html">JNI Specification</externallink>
8125         and are referred to as <code>field descriptors</code> in
8126         <vmspec chapter="4.3.2"/>.
8127       </description>
8128       <origin>jvmdiClone</origin>
8129       <capabilities>
8130       </capabilities>
8131       <parameters>
8132         <param id="klass">
8133           <jclass field="field"/>
8134             <description>
8135               The class of the field to query.
8136             </description>
8137         </param>
8138         <param id="field">
8139           <jfieldID class="klass"/>
8140             <description>
8141               The field to query.
8142             </description>
8143         </param>
8144         <param id="name_ptr">
8145           <allocbuf>
8146             <char/>
8147             <nullok>the name is not returned</nullok>
8148           </allocbuf>
8149           <description>
8150             On return, points to the field name, encoded as a
8151             <internallink id="mUTF">modified UTF-8</internallink> string.
8152           </description>
8153         </param>
8154         <param id="signature_ptr">
8155           <allocbuf>
8156             <char/>
8157             <nullok>the signature is not returned</nullok>
8158           </allocbuf>
8159           <description>
8160             On return, points to the field signature, encoded as a
8161             <internallink id="mUTF">modified UTF-8</internallink> string.
8162           </description>
8163         </param>
8164         <param id="generic_ptr">
8165           <allocbuf>
8166             <char/>
8167             <nullok>the generic signature is not returned</nullok>
8168           </allocbuf>
8169           <description>
8170             On return, points to the generic signature of the field, encoded as a
8171             <internallink id="mUTF">modified UTF-8</internallink> string.
8172             If there is no generic signature attribute for the field, then,
8173             on return, points to <code>NULL</code>.
8174           </description>
8175         </param>
8176       </parameters>
8177       <errors>
8178       </errors>
8179     </function>
8180 
8181     <function id="GetFieldDeclaringClass" phase="start" num="61">
8182       <synopsis>Get Field Declaring Class</synopsis>
8183       <description>
8184         For the field indicated by <code>klass</code> and <code>field</code>
8185         return the class that defined it via <code>declaring_class_ptr</code>.
8186         The declaring class will either be <code>klass</code>, a superclass, or
8187         an implemented interface.
8188       </description>
8189       <origin>jvmdi</origin>
8190       <capabilities>
8191       </capabilities>
8192       <parameters>
8193         <param id="klass">
8194           <jclass field="field"/>
8195             <description>
8196               The class to query.
8197             </description>
8198         </param>
8199         <param id="field">
8200           <jfieldID class="klass"/>
8201             <description>
8202               The field to query.
8203             </description>
8204         </param>
8205         <param id="declaring_class_ptr">
8206           <outptr><jclass/></outptr>
8207             <description>
8208               On return, points to the declaring class
8209             </description>
8210         </param>
8211       </parameters>
8212       <errors>
8213       </errors>
8214     </function>
8215 
8216     <function id="GetFieldModifiers" phase="start" num="62">
8217       <synopsis>Get Field Modifiers</synopsis>
8218       <description>
8219         For the field indicated by <code>klass</code> and <code>field</code>
8220         return the access flags via <code>modifiers_ptr</code>.
8221         Access flags are defined in <vmspec chapter="4"/>.
8222       </description>
8223       <origin>jvmdi</origin>
8224       <capabilities>
8225       </capabilities>
8226       <parameters>
8227         <param id="klass">
8228           <jclass field="field"/>
8229             <description>
8230               The class to query.
8231             </description>
8232         </param>
8233         <param id="field">
8234           <jfieldID class="klass"/>
8235             <description>
8236               The field to query.
8237             </description>
8238         </param>
8239         <param id="modifiers_ptr">
8240           <outptr><jint/></outptr>
8241           <description>
8242             On return, points to the access flags.
8243           </description>
8244         </param>
8245       </parameters>
8246       <errors>
8247       </errors>
8248     </function>
8249 
8250     <function id="IsFieldSynthetic" phase="start" num="63">
8251       <synopsis>Is Field Synthetic</synopsis>
8252       <description>
8253         For the field indicated by <code>klass</code> and <code>field</code>, return a
8254         value indicating whether the field is synthetic via <code>is_synthetic_ptr</code>.
8255         Synthetic fields are generated by the compiler but not present in the
8256         original source code.
8257       </description>
8258       <origin>jvmdi</origin>
8259       <capabilities>
8260         <required id="can_get_synthetic_attribute"></required>
8261       </capabilities>
8262       <parameters>
8263         <param id="klass">
8264           <jclass field="field"/>
8265             <description>
8266               The class of the field to query.
8267             </description>
8268         </param>
8269         <param id="field">
8270           <jfieldID class="klass"/>
8271             <description>
8272               The field to query.
8273             </description>
8274         </param>
8275         <param id="is_synthetic_ptr">
8276           <outptr><jboolean/></outptr>
8277           <description>
8278             On return, points to the boolean result of this function.
8279           </description>
8280         </param>
8281       </parameters>
8282       <errors>
8283       </errors>
8284     </function>
8285 
8286   </category>
8287 
8288   <category id="method" label="Method">
8289 
8290     <intro>
8291       These functions provide information about a method (represented as a
8292       <typelink id="jmethodID"/>) and set how methods are processed.
8293     </intro>
8294 
8295     <intro id="obsoleteMethods" label="Obsolete Methods">
8296       The functions <functionlink id="RetransformClasses"/> and
8297       <functionlink id="RedefineClasses"/> can cause new versions
8298       of methods to be installed.
8299       An original version of a method is considered equivalent
8300       to the new version if:
8301       <ul>
8302         <li>their bytecodes are the same except for indices into the
8303           constant pool and </li>
8304         <li>the referenced constants are equal.</li>
8305       </ul>
8306       An original method version which is not equivalent to the
8307       new method version is called obsolete and is assigned a new method ID;
8308       the original method ID now refers to the new method version.
8309       A method ID can be tested for obsolescence with
8310       <functionlink id="IsMethodObsolete"/>.
8311     </intro>
8312 
8313     <function id="GetMethodName" phase="start" num="64">
8314       <synopsis>Get Method Name (and Signature)</synopsis>
8315       <description>
8316         For the method indicated by <code>method</code>,
8317         return the method name via <code>name_ptr</code> and method signature via
8318         <code>signature_ptr</code>.
8319         <p/>
8320         Method signatures are defined in the
8321         <externallink id="jni/index.html">JNI Specification</externallink>
8322         and are referred to as <code>method descriptors</code> in
8323         <vmspec chapter="4.3.3"/>.
8324         Note this is different
8325         than method signatures as defined in the <i>Java Language Specification</i>.
8326       </description>
8327       <origin>jvmdiClone</origin>
8328       <capabilities>
8329       </capabilities>
8330       <parameters>
8331         <param id="method">
8332           <jmethodID/>
8333             <description>
8334               The method to query.
8335             </description>
8336         </param>
8337         <param id="name_ptr">
8338           <allocbuf>
8339             <char/>
8340             <nullok>the name is not returned</nullok>
8341           </allocbuf>
8342           <description>
8343             On return, points to the method name, encoded as a
8344             <internallink id="mUTF">modified UTF-8</internallink> string.
8345           </description>
8346         </param>
8347         <param id="signature_ptr">
8348           <allocbuf>
8349             <char/>
8350             <nullok>the signature is not returned</nullok>
8351           </allocbuf>
8352           <description>
8353             On return, points to the method signature, encoded as a
8354             <internallink id="mUTF">modified UTF-8</internallink> string.
8355           </description>
8356         </param>
8357         <param id="generic_ptr">
8358           <allocbuf>
8359             <char/>
8360             <nullok>the generic signature is not returned</nullok>
8361           </allocbuf>
8362           <description>
8363             On return, points to the generic signature of the method, encoded as a
8364             <internallink id="mUTF">modified UTF-8</internallink> string.
8365             If there is no generic signature attribute for the method, then,
8366             on return, points to <code>NULL</code>.
8367           </description>
8368         </param>
8369       </parameters>
8370       <errors>
8371       </errors>
8372     </function>
8373 
8374     <function id="GetMethodDeclaringClass" phase="start" num="65">
8375       <synopsis>Get Method Declaring Class</synopsis>
8376       <description>
8377         For the method indicated by <code>method</code>,
8378         return the class that defined it via <code>declaring_class_ptr</code>.
8379       </description>
8380       <origin>jvmdi</origin>
8381       <capabilities>
8382       </capabilities>
8383       <parameters>
8384         <param id="klass">
8385           <jclass method="method"/>
8386             <description>
8387               The class to query.
8388             </description>
8389         </param>
8390         <param id="method">
8391           <jmethodID class="klass"/>
8392             <description>
8393               The method to query.
8394             </description>
8395         </param>
8396         <param id="declaring_class_ptr">
8397           <outptr><jclass/></outptr>
8398             <description>
8399               On return, points to the declaring class
8400             </description>
8401         </param>
8402       </parameters>
8403       <errors>
8404       </errors>
8405     </function>
8406 
8407     <function id="GetMethodModifiers" phase="start" num="66">
8408       <synopsis>Get Method Modifiers</synopsis>
8409       <description>
8410         For the method indicated by <code>method</code>,
8411         return the access flags via <code>modifiers_ptr</code>.
8412         Access flags are defined in <vmspec chapter="4"/>.
8413       </description>
8414       <origin>jvmdi</origin>
8415       <capabilities>
8416       </capabilities>
8417       <parameters>
8418         <param id="klass">
8419           <jclass method="method"/>
8420             <description>
8421               The class to query.
8422             </description>
8423         </param>
8424         <param id="method">
8425           <jmethodID class="klass"/>
8426             <description>
8427               The method to query.
8428             </description>
8429         </param>
8430         <param id="modifiers_ptr">
8431           <outptr><jint/></outptr>
8432           <description>
8433             On return, points to the access flags.
8434           </description>
8435         </param>
8436       </parameters>
8437       <errors>
8438       </errors>
8439     </function>
8440 
8441     <function id="GetMaxLocals" phase="start" num="68">
8442       <synopsis>Get Max Locals</synopsis>
8443       <description>
8444           For the method indicated by <code>method</code>,
8445           return the number of local variable slots used by the method,
8446           including the local variables used to pass parameters to the
8447           method on its invocation.
8448           <p/>
8449           See <code>max_locals</code> in <vmspec chapter="4.7.3"/>.
8450       </description>
8451       <origin>jvmdi</origin>
8452       <capabilities>
8453       </capabilities>
8454       <parameters>
8455         <param id="klass">
8456           <jclass method="method"/>
8457             <description>
8458               The class to query.
8459             </description>
8460         </param>
8461         <param id="method">
8462           <jmethodID class="klass" native="error"/>
8463             <description>
8464               The method to query.
8465             </description>
8466         </param>
8467         <param id="max_ptr">
8468           <outptr><jint/></outptr>
8469           <description>
8470             On return, points to the maximum number of local slots
8471           </description>
8472         </param>
8473       </parameters>
8474       <errors>
8475       </errors>
8476     </function>
8477 
8478     <function id="GetArgumentsSize" phase="start" num="69">
8479       <synopsis>Get Arguments Size</synopsis>
8480       <description>
8481         For the method indicated by <code>method</code>,
8482         return via <code>max_ptr</code> the number of local variable slots used
8483         by the method's arguments.
8484         Note that two-word arguments use two slots.
8485       </description>
8486       <origin>jvmdi</origin>
8487       <capabilities>
8488       </capabilities>
8489       <parameters>
8490         <param id="klass">
8491           <jclass method="method"/>
8492             <description>
8493               The class to query.
8494             </description>
8495         </param>
8496         <param id="method">
8497           <jmethodID class="klass" native="error"/>
8498             <description>
8499               The method to query.
8500             </description>
8501         </param>
8502         <param id="size_ptr">
8503           <outptr><jint/></outptr>
8504           <description>
8505             On return, points to the number of argument slots
8506           </description>
8507         </param>
8508       </parameters>
8509       <errors>
8510       </errors>
8511     </function>
8512 
8513     <function id="GetLineNumberTable" phase="start" num="70">
8514       <synopsis>Get Line Number Table</synopsis>
8515       <typedef id="jvmtiLineNumberEntry" label="Line number table entry">
8516         <field id="start_location">
8517           <jlocation/>
8518           <description>
8519             the <datalink id="jlocation"></datalink> where the line begins
8520           </description>
8521         </field>
8522         <field id="line_number">
8523           <jint/>
8524           <description>
8525             the line number
8526           </description>
8527         </field>
8528       </typedef>
8529       <description>
8530         For the method indicated by <code>method</code>,
8531         return a table of source line number entries. The size of the table is
8532         returned via <code>entry_count_ptr</code> and the table itself is
8533         returned via <code>table_ptr</code>.
8534       </description>
8535       <origin>jvmdi</origin>
8536       <capabilities>
8537         <required id="can_get_line_numbers"></required>
8538       </capabilities>
8539       <parameters>
8540         <param id="klass">
8541           <jclass method="method"/>
8542             <description>
8543               The class to query.
8544             </description>
8545         </param>
8546         <param id="method">
8547           <jmethodID class="klass" native="error"/>
8548             <description>
8549               The method to query.
8550             </description>
8551         </param>
8552         <param id="entry_count_ptr">
8553           <outptr><jint/></outptr>
8554           <description>
8555             On return, points to the number of entries in the table
8556           </description>
8557         </param>
8558         <param id="table_ptr">
8559           <allocbuf outcount="entry_count_ptr"><struct>jvmtiLineNumberEntry</struct></allocbuf>
8560           <description>
8561             On return, points to the line number table pointer.
8562           </description>
8563         </param>
8564       </parameters>
8565       <errors>
8566         <error id="JVMTI_ERROR_ABSENT_INFORMATION">
8567           Class information does not include line numbers.
8568         </error>
8569       </errors>
8570     </function>
8571 
8572     <function id="GetMethodLocation" phase="start" num="71">
8573       <synopsis>Get Method Location</synopsis>
8574       <description>
8575         For the method indicated by <code>method</code>,
8576         return the beginning and ending addresses through
8577         <code>start_location_ptr</code> and <code>end_location_ptr</code>. In a
8578         conventional bytecode indexing scheme,
8579         <code>start_location_ptr</code> will always point to zero
8580         and <code>end_location_ptr</code>
8581         will always point to the bytecode count minus one.
8582       </description>
8583       <origin>jvmdi</origin>
8584       <capabilities>
8585       </capabilities>
8586       <parameters>
8587         <param id="klass">
8588           <jclass method="method"/>
8589             <description>
8590               The class to query.
8591             </description>
8592         </param>
8593         <param id="method">
8594           <jmethodID class="klass" native="error"/>
8595             <description>
8596               The method to query.
8597             </description>
8598         </param>
8599         <param id="start_location_ptr">
8600           <outptr><jlocation/></outptr>
8601           <description>
8602             On return, points to the first location, or
8603             <code>-1</code> if location information is not available.
8604             If the information is available and
8605             <functionlink id="GetJLocationFormat"></functionlink>
8606             returns <datalink id="JVMTI_JLOCATION_JVMBCI"></datalink>
8607             then this will always be zero.
8608           </description>
8609         </param>
8610         <param id="end_location_ptr">
8611           <outptr><jlocation/></outptr>
8612           <description>
8613             On return, points to the last location,
8614             or <code>-1</code> if location information is not available.
8615           </description>
8616         </param>
8617       </parameters>
8618       <errors>
8619         <error id="JVMTI_ERROR_ABSENT_INFORMATION">
8620           Class information does not include method sizes.
8621         </error>
8622       </errors>
8623     </function>
8624 
8625     <function id="GetLocalVariableTable" num="72">
8626       <synopsis>Get Local Variable Table</synopsis>
8627       <typedef id="jvmtiLocalVariableEntry" label="Local variable table entry">
8628         <field id="start_location">
8629           <jlocation/>
8630           <description>
8631             The code array index where the local variable is first valid
8632             (that is, where it must have a value).
8633           </description>
8634         </field>
8635         <field id="length">
8636           <jint/>
8637           <description>
8638             The length of the valid section for this local variable.
8639             The last code array index where the local variable is valid
8640             is <code>start_location + length</code>.
8641           </description>
8642         </field>
8643         <field id="name">
8644           <allocfieldbuf><char/></allocfieldbuf>
8645           <description>
8646             The local variable name, encoded as a
8647             <internallink id="mUTF">modified UTF-8</internallink> string.
8648           </description>
8649         </field>
8650         <field id="signature">
8651           <allocfieldbuf><char/></allocfieldbuf>
8652           <description>
8653             The local variable's type signature, encoded as a
8654             <internallink id="mUTF">modified UTF-8</internallink> string.
8655             The signature format is the same as that defined in
8656             <vmspec chapter="4.3.2"/>.
8657           </description>
8658         </field>
8659         <field id="generic_signature">
8660           <allocfieldbuf><char/></allocfieldbuf>
8661           <description>
8662             The local variable's generic signature, encoded as a
8663             <internallink id="mUTF">modified UTF-8</internallink> string.
8664             The value of this field will be <code>NULL</code> for any local
8665             variable which does not have a generic type.
8666           </description>
8667         </field>
8668         <field id="slot">
8669           <jint/>
8670           <description>
8671             The local variable's slot.  See <internallink id="local">Local Variables</internallink>.
8672           </description>
8673         </field>
8674       </typedef>
8675       <description>
8676         Return local variable information.
8677       </description>
8678       <origin>jvmdiClone</origin>
8679       <capabilities>
8680         <required id="can_access_local_variables"></required>
8681       </capabilities>
8682       <parameters>
8683         <param id="method">
8684           <jmethodID native="error"/>
8685             <description>
8686               The method to query.
8687             </description>
8688         </param>
8689         <param id="entry_count_ptr">
8690           <outptr><jint/></outptr>
8691           <description>
8692             On return, points to the number of entries in the table
8693           </description>
8694         </param>
8695         <param id="table_ptr">
8696           <allocbuf outcount="entry_count_ptr"><struct>jvmtiLocalVariableEntry</struct></allocbuf>
8697           <description>
8698             On return, points to an array of local variable table entries.
8699           </description>
8700         </param>
8701       </parameters>
8702       <errors>
8703         <error id="JVMTI_ERROR_ABSENT_INFORMATION">
8704           Class information does not include local variable
8705           information.
8706         </error>
8707       </errors>
8708     </function>
8709 
8710     <function id="GetBytecodes" phase="start" num="75">
8711       <synopsis>Get Bytecodes</synopsis>
8712       <description>
8713         For the method indicated by <code>method</code>,
8714         return the bytecodes that implement the method. The number of
8715         bytecodes is returned via <code>bytecode_count_ptr</code>. The bytecodes
8716         themselves are returned via <code>bytecodes_ptr</code>.
8717       </description>
8718       <origin>jvmdi</origin>
8719       <capabilities>
8720         <required id="can_get_bytecodes"></required>
8721       </capabilities>
8722       <parameters>
8723         <param id="klass">
8724           <jclass method="method"/>
8725             <description>
8726               The class to query.
8727             </description>
8728         </param>
8729         <param id="method">
8730           <jmethodID class="klass" native="error"/>
8731             <description>
8732               The method to query.
8733             </description>
8734         </param>
8735         <param id="bytecode_count_ptr">
8736           <outptr><jint/></outptr>
8737           <description>
8738             On return, points to the length of the bytecode array
8739           </description>
8740         </param>
8741         <param id="bytecodes_ptr">
8742           <allocbuf outcount="bytecode_count_ptr"><uchar/></allocbuf>
8743           <description>
8744             On return, points to the pointer to the bytecode array
8745           </description>
8746         </param>
8747       </parameters>
8748       <errors>
8749       </errors>
8750     </function>
8751 
8752     <function id="IsMethodNative" phase="start" num="76">
8753       <synopsis>Is Method Native</synopsis>
8754       <description>
8755         For the method indicated by <code>method</code>, return a
8756         value indicating whether the method is native via <code>is_native_ptr</code>
8757       </description>
8758       <origin>jvmdi</origin>
8759       <capabilities>
8760       </capabilities>
8761       <parameters>
8762         <param id="klass">
8763           <jclass method="method"/>
8764             <description>
8765               The class to query.
8766             </description>
8767         </param>
8768         <param id="method">
8769           <jmethodID class="klass"/>
8770             <description>
8771               The method to query.
8772             </description>
8773         </param>
8774         <param id="is_native_ptr">
8775           <outptr><jboolean/></outptr>
8776           <description>
8777             On return, points to the boolean result of this function.
8778           </description>
8779         </param>
8780       </parameters>
8781       <errors>
8782       </errors>
8783     </function>
8784 
8785     <function id="IsMethodSynthetic" phase="start" num="77">
8786       <synopsis>Is Method Synthetic</synopsis>
8787       <description>
8788         For the method indicated by <code>method</code>, return a
8789         value indicating whether the method is synthetic via <code>is_synthetic_ptr</code>.
8790         Synthetic methods are generated by the compiler but not present in the
8791         original source code.
8792       </description>
8793       <origin>jvmdi</origin>
8794       <capabilities>
8795         <required id="can_get_synthetic_attribute"></required>
8796       </capabilities>
8797       <parameters>
8798         <param id="klass">
8799           <jclass method="method"/>
8800             <description>
8801               The class to query.
8802             </description>
8803         </param>
8804         <param id="method">
8805           <jmethodID class="klass"/>
8806             <description>
8807               The method to query.
8808             </description>
8809         </param>
8810         <param id="is_synthetic_ptr">
8811           <outptr><jboolean/></outptr>
8812           <description>
8813             On return, points to the boolean result of this function.
8814           </description>
8815         </param>
8816       </parameters>
8817       <errors>
8818       </errors>
8819     </function>
8820 
8821     <function id="IsMethodObsolete" phase="start" num="91">
8822       <synopsis>Is Method Obsolete</synopsis>
8823       <description>
8824         Determine if a method ID refers to an
8825         <internallink id="obsoleteMethods">obsolete</internallink>
8826         method version.
8827       </description>
8828       <origin>jvmdi</origin>
8829       <capabilities>
8830       </capabilities>
8831       <parameters>
8832         <param id="klass">
8833           <jclass method="method"/>
8834             <description>
8835               The class to query.
8836             </description>
8837         </param>
8838         <param id="method">
8839           <jmethodID class="klass"/>
8840             <description>
8841               The method ID to query.
8842             </description>
8843         </param>
8844         <param id="is_obsolete_ptr">
8845           <outptr><jboolean/></outptr>
8846           <description>
8847             On return, points to the boolean result of this function.
8848           </description>
8849         </param>
8850       </parameters>
8851       <errors>
8852       </errors>
8853     </function>
8854 
8855     <function id="SetNativeMethodPrefix" jkernel="yes" phase="any" num="73" since="1.1">
8856       <synopsis>Set Native Method Prefix</synopsis>
8857       <description>
8858         This function modifies the failure handling of
8859         native method resolution by allowing retry
8860         with a prefix applied to the name.
8861         When used with the
8862         <eventlink id="ClassFileLoadHook">ClassFileLoadHook
8863         event</eventlink>, it enables native methods to be
8864         <internallink id="bci">instrumented</internallink>.
8865         <p/>
8866         Since native methods cannot be directly instrumented
8867         (they have no bytecodes), they must be wrapped with
8868         a non-native method which can be instrumented.
8869         For example, if we had:
8870         <example>
8871 native boolean foo(int x);</example>
8872         <p/>
8873         We could transform the class file (with the
8874         ClassFileLoadHook event) so that this becomes:
8875         <example>
8876 boolean foo(int x) {
8877   <i>... record entry to foo ...</i>
8878   return wrapped_foo(x);
8879 }
8880 
8881 native boolean wrapped_foo(int x);</example>
8882         <p/>
8883         Where foo becomes a wrapper for the actual native method
8884         with the appended prefix "wrapped_".  Note that
8885         "wrapped_" would be a poor choice of prefix since it
8886         might conceivably form the name of an existing method
8887         thus something like "$$$MyAgentWrapped$$$_" would be
8888         better but would make these examples less readable.
8889         <p/>
8890         The wrapper will allow data to be collected on the native
8891         method call, but now the problem becomes linking up the
8892         wrapped method with the native implementation.
8893         That is, the method <code>wrapped_foo</code> needs to be
8894         resolved to the native implementation of <code>foo</code>,
8895         which might be:
8896         <example>
8897 Java_somePackage_someClass_foo(JNIEnv* env, jint x)</example>
8898         <p/>
8899         This function allows the prefix to be specified and the
8900         proper resolution to occur.
8901         Specifically, when the standard resolution fails, the
8902         resolution is retried taking the prefix into consideration.
8903         There are two ways that resolution occurs, explicit
8904         resolution with the JNI function <code>RegisterNatives</code>
8905         and the normal automatic resolution.  For
8906         <code>RegisterNatives</code>, the VM will attempt this
8907         association:
8908         <example>
8909 method(foo) -> nativeImplementation(foo)</example>
8910         <p/>
8911         When this fails, the resolution will be retried with
8912         the specified prefix prepended to the method name,
8913         yielding the correct resolution:
8914         <example>
8915 method(wrapped_foo) -> nativeImplementation(foo)</example>
8916         <p/>
8917         For automatic resolution, the VM will attempt:
8918         <example>
8919 method(wrapped_foo) -> nativeImplementation(wrapped_foo)</example>
8920         <p/>
8921         When this fails, the resolution will be retried with
8922         the specified prefix deleted from the implementation name,
8923         yielding the correct resolution:
8924         <example>
8925 method(wrapped_foo) -> nativeImplementation(foo)</example>
8926         <p/>
8927         Note that since the prefix is only used when standard
8928         resolution fails, native methods can be wrapped selectively.
8929         <p/>
8930         Since each <jvmti/> environment is independent and
8931         can do its own transformation of the bytecodes, more
8932         than one layer of wrappers may be applied. Thus each
8933         environment needs its own prefix.  Since transformations
8934         are applied in order, the prefixes, if applied, will
8935         be applied in the same order.
8936         The order of transformation application is described in
8937         the <eventlink id="ClassFileLoadHook"/> event.
8938         Thus if three environments applied
8939         wrappers, <code>foo</code> might become
8940         <code>$env3_$env2_$env1_foo</code>.  But if, say,
8941         the second environment did not apply a wrapper to
8942         <code>foo</code> it would be just
8943         <code>$env3_$env1_foo</code>.  To be able to
8944         efficiently determine the sequence of prefixes,
8945         an intermediate prefix is only applied if its non-native
8946         wrapper exists.  Thus, in the last example, even though
8947         <code>$env1_foo</code> is not a native method, the
8948         <code>$env1_</code> prefix is applied since
8949         <code>$env1_foo</code> exists.
8950         <p/>
8951         Since the prefixes are used at resolution time
8952         and since resolution may be arbitrarily delayed, a
8953         native method prefix must remain set as long as there
8954         are corresponding prefixed native methods.
8955       </description>
8956       <origin>new</origin>
8957       <capabilities>
8958         <required id="can_set_native_method_prefix"></required>
8959       </capabilities>
8960       <parameters>
8961         <param id="prefix">
8962           <inbuf>
8963             <char/>
8964             <nullok>
8965               any existing prefix in this environment is cancelled
8966             </nullok>
8967           </inbuf>
8968           <description>
8969             The prefix to apply, encoded as a
8970             <internallink id="mUTF">modified UTF-8</internallink> string.
8971           </description>
8972         </param>
8973       </parameters>
8974       <errors>
8975       </errors>
8976     </function>
8977 
8978     <function id="SetNativeMethodPrefixes" jkernel="yes" phase="any" num="74" since="1.1">
8979       <synopsis>Set Native Method Prefixes</synopsis>
8980       <description>
8981          For a normal agent, <functionlink id="SetNativeMethodPrefix"/>
8982          will provide all needed native method prefixing.
8983          For a meta-agent that performs multiple independent class
8984          file transformations (for example as a proxy for another
8985          layer of agents) this function allows each transformation
8986          to have its own prefix.
8987          The prefixes are applied in the order supplied and are
8988          processed in the same manner as described for the
8989          application of prefixes from multiple <jvmti/> environments
8990          in <functionlink id="SetNativeMethodPrefix"/>.
8991          <p/>
8992          Any previous prefixes are replaced.  Thus, calling this
8993          function with a <paramlink id="prefix_count"/> of <code>0</code>
8994          disables prefixing in this environment.
8995          <p/>
8996          <functionlink id="SetNativeMethodPrefix"/> and this function
8997          are the two ways to set the prefixes.
8998          Calling <code>SetNativeMethodPrefix</code> with
8999          a prefix is the same as calling this function with
9000          <paramlink id="prefix_count"/> of <code>1</code>.
9001          Calling <code>SetNativeMethodPrefix</code> with
9002          <code>NULL</code> is the same as calling this function with
9003          <paramlink id="prefix_count"/> of <code>0</code>.
9004       </description>
9005       <origin>new</origin>
9006       <capabilities>
9007         <required id="can_set_native_method_prefix"></required>
9008       </capabilities>
9009       <parameters>
9010         <param id="prefix_count">
9011           <jint min="0"/>
9012             <description>
9013               The number of prefixes to apply.
9014             </description>
9015         </param>
9016         <param id="prefixes">
9017           <agentbuf>
9018             <char/>
9019           </agentbuf>
9020           <description>
9021             The prefixes to apply for this environment, each encoded as a
9022             <internallink id="mUTF">modified UTF-8</internallink> string.
9023           </description>
9024         </param>
9025       </parameters>
9026       <errors>
9027       </errors>
9028     </function>
9029 
9030   </category>
9031 
9032   <category id="RawMonitors" label="Raw Monitor">
9033 
9034     <function id="CreateRawMonitor" phase="onload" callbacksafe="safe" num="31">
9035       <synopsis>Create Raw Monitor</synopsis>
9036       <description>
9037         Create a raw monitor.
9038       </description>
9039       <origin>jvmdi</origin>
9040       <capabilities>
9041       </capabilities>
9042       <parameters>
9043         <param id="name">
9044           <inbuf><char/></inbuf>
9045           <description>
9046             A name to identify the monitor, encoded as a
9047             <internallink id="mUTF">modified UTF-8</internallink> string.
9048           </description>
9049         </param>
9050         <param id="monitor_ptr">
9051           <outptr><jrawMonitorID/></outptr>
9052           <description>
9053             On return, points to the created monitor.
9054           </description>
9055         </param>
9056       </parameters>
9057       <errors>
9058       </errors>
9059     </function>
9060 
9061     <function id="DestroyRawMonitor" phase="onload" callbacksafe="safe" num="32">
9062       <synopsis>Destroy Raw Monitor</synopsis>
9063       <description>
9064         Destroy the raw monitor.
9065         If the monitor being destroyed has been entered by this thread, it will be
9066         exited before it is destroyed.
9067         If the monitor being destroyed has been entered by another thread,
9068         an error will be returned and the monitor will not be destroyed.
9069       </description>
9070       <origin>jvmdi</origin>
9071       <capabilities>
9072       </capabilities>
9073       <parameters>
9074         <param id="monitor">
9075           <jrawMonitorID/>
9076           <description>
9077             The monitor
9078           </description>
9079         </param>
9080       </parameters>
9081       <errors>
9082         <error id="JVMTI_ERROR_NOT_MONITOR_OWNER">
9083           Not monitor owner
9084         </error>
9085       </errors>
9086     </function>
9087 
9088     <function id="RawMonitorEnter" phase="any" callbacksafe="safe" impl="innative notrace" num="33">
9089       <synopsis>Raw Monitor Enter</synopsis>
9090       <description>
9091         Gain exclusive ownership of a raw monitor.
9092         The same thread may enter a monitor more then once.
9093         The thread must
9094         <functionlink id="RawMonitorExit">exit</functionlink>
9095         the monitor the same number of times as it is entered.
9096         If a monitor is entered during <code>OnLoad</code> (before attached threads exist)
9097         and has not exited when attached threads come into existence, the enter
9098         is considered to have occurred on the main thread.
9099       </description>
9100       <origin>jvmdi</origin>
9101       <capabilities>
9102       </capabilities>
9103       <parameters>
9104         <param id="monitor">
9105           <jrawMonitorID/>
9106           <description>
9107             The monitor
9108           </description>
9109         </param>
9110       </parameters>
9111       <errors>
9112       </errors>
9113     </function>
9114 
9115     <function id="RawMonitorExit" phase="any" callbacksafe="safe" impl="innative notrace" num="34">
9116       <synopsis>Raw Monitor Exit</synopsis>
9117       <description>
9118         Release exclusive ownership of a raw monitor.
9119       </description>
9120       <origin>jvmdi</origin>
9121       <capabilities>
9122       </capabilities>
9123       <parameters>
9124         <param id="monitor">
9125           <jrawMonitorID/>
9126           <description>
9127             The monitor
9128           </description>
9129         </param>
9130       </parameters>
9131       <errors>
9132         <error id="JVMTI_ERROR_NOT_MONITOR_OWNER">
9133           Not monitor owner
9134         </error>
9135       </errors>
9136     </function>
9137 
9138     <function id="RawMonitorWait" phase="any" callbacksafe="safe" impl="innative notrace" num="35">
9139       <synopsis>Raw Monitor Wait</synopsis>
9140       <description>
9141         Wait for notification of the raw monitor.
9142         <p/>
9143         Causes the current thread to wait until either another thread calls
9144         <functionlink id="RawMonitorNotify"/> or
9145         <functionlink id="RawMonitorNotifyAll"/>
9146         for the specified raw monitor, or the specified
9147         <paramlink id="millis">timeout</paramlink>
9148         has elapsed.
9149       </description>
9150       <origin>jvmdi</origin>
9151       <capabilities>
9152       </capabilities>
9153       <parameters>
9154         <param id="monitor">
9155           <jrawMonitorID/>
9156           <description>
9157             The monitor
9158           </description>
9159         </param>
9160         <param id="millis">
9161           <jlong/>
9162           <description>
9163             The timeout, in milliseconds.  If the timeout is
9164             zero, then real time is not taken into consideration
9165             and the thread simply waits until notified.
9166           </description>
9167         </param>
9168       </parameters>
9169       <errors>
9170         <error id="JVMTI_ERROR_NOT_MONITOR_OWNER">
9171           Not monitor owner
9172         </error>
9173         <error id="JVMTI_ERROR_INTERRUPT">
9174           Wait was interrupted, try again
9175         </error>
9176       </errors>
9177     </function>
9178 
9179     <function id="RawMonitorNotify" phase="any" callbacksafe="safe" impl="notrace" num="36">
9180       <synopsis>Raw Monitor Notify</synopsis>
9181       <description>
9182         Notify a single thread waiting on the raw monitor.
9183       </description>
9184       <origin>jvmdi</origin>
9185       <capabilities>
9186       </capabilities>
9187       <parameters>
9188         <param id="monitor">
9189           <jrawMonitorID/>
9190           <description>
9191             The monitor
9192           </description>
9193         </param>
9194       </parameters>
9195       <errors>
9196         <error id="JVMTI_ERROR_NOT_MONITOR_OWNER">
9197           Not monitor owner
9198         </error>
9199       </errors>
9200     </function>
9201 
9202     <function id="RawMonitorNotifyAll" phase="any" callbacksafe="safe" impl="notrace" num="37">
9203       <synopsis>Raw Monitor Notify All</synopsis>
9204       <description>
9205         Notify all threads waiting on the raw monitor.
9206       </description>
9207       <origin>jvmdi</origin>
9208       <capabilities>
9209       </capabilities>
9210       <parameters>
9211         <param id="monitor">
9212           <jrawMonitorID/>
9213           <description>
9214             The monitor
9215           </description>
9216         </param>
9217       </parameters>
9218       <errors>
9219         <error id="JVMTI_ERROR_NOT_MONITOR_OWNER">
9220           Not monitor owner
9221         </error>
9222       </errors>
9223     </function>
9224 
9225    <elide>
9226     <function id="GetRawMonitorUse" num="118">
9227       <synopsis>Get Raw Monitor Use</synopsis>
9228       <description>
9229         The fields of the <functionlink id="jvmtiMonitorUsage"></functionlink> structure
9230         are filled in with information about usage of the raw monitor.
9231       </description>
9232       <origin>new</origin>
9233       <capabilities>
9234         <required id="can_get_raw_monitor_usage"></required>
9235       </capabilities>
9236       <parameters>
9237         <param id="monitor">
9238           <jrawMonitorID/>
9239           <description>
9240             the raw monitor to query.
9241           </description>
9242         </param>
9243         <param id="info_ptr">
9244           <outptr><struct>jvmtiMonitorUsage</struct></outptr>
9245           <description>
9246             On return, filled with monitor information for the
9247             specified raw monitor.
9248           </description>
9249         </param>
9250       </parameters>
9251       <errors>
9252       </errors>
9253     </function>
9254 
9255     <function id="GetRawMonitors" num="119">
9256       <synopsis>Get Raw Monitors</synopsis>
9257       <description>
9258         Return the list of raw monitors.
9259         <p/>
9260         Note: details about each monitor can be examined with
9261         <functionlink id="GetRawMonitorUse"></functionlink>.
9262       </description>
9263       <origin>new</origin>
9264       <capabilities>
9265         <required id="can_get_raw_monitor_usage"></required>
9266       </capabilities>
9267       <parameters>
9268         <param id="monitorCnt">
9269           <outptr><jint/></outptr>
9270           <description>
9271             On return, pointer to the number
9272             of monitors returned in <code>monitors_ptr</code>.
9273           </description>
9274         </param>
9275         <param id="monitors_ptr">
9276           <allocbuf outcount="monitorCnt"><jrawMonitorID/></allocbuf>
9277           <description>
9278             On return, pointer to the monitor list.
9279           </description>
9280         </param>
9281       </parameters>
9282       <errors>
9283       </errors>
9284     </function>
9285     </elide>
9286   </category>
9287 
9288   <category id="jniIntercept" label="JNI Function Interception">
9289 
9290     <intro>
9291       Provides the ability to intercept and resend
9292       Java Native Interface (JNI) function calls
9293       by manipulating the JNI function table.
9294       See <externallink id="jni/functions.html">JNI
9295         Functions</externallink> in the <i>Java Native Interface Specification</i>.
9296       <p/>
9297       The following example illustrates intercepting the
9298       <code>NewGlobalRef</code> JNI call in order to count reference
9299       creation.
9300       <example>
9301 JNIEnv original_jni_Functions;
9302 JNIEnv redirected_jni_Functions;
9303 int my_global_ref_count = 0;
9304 
9305 jobject
9306 MyNewGlobalRef(JNIEnv *jni_env, jobject lobj) {
9307    ++my_global_ref_count;
9308    return originalJNIFunctions-&gt;NewGlobalRef(env, lobj);
9309 }
9310 
9311 void
9312 myInit() {
9313    jvmtiError err;
9314 
9315    err = (*jvmti_env)-&gt;GetJNIFunctionTable(jvmti_env, &amp;original_jni_Functions);
9316    if (err != JVMTI_ERROR_NONE) {
9317       die();
9318    }
9319    err = (*jvmti_env)-&gt;GetJNIFunctionTable(jvmti_env, &amp;redirected_jni_Functions);
9320    if (err != JVMTI_ERROR_NONE) {
9321       die();
9322    }
9323    redirectedJNIFunctions-&gt;NewGlobalRef = MyNewGlobalRef;
9324       err = (*jvmti_env)-&gt;SetJNIFunctionTable(jvmti_env, redirected_jni_Functions);
9325    if (err != JVMTI_ERROR_NONE) {
9326       die();
9327    }
9328 }
9329       </example>
9330       Sometime after <code>myInit</code> is called the user's JNI
9331       code is executed which makes the call to create a new global
9332       reference.  Instead of going to the normal JNI implementation
9333       the call goes to <code>myNewGlobalRef</code>.  Note that a
9334       copy of the original function table is kept so that the normal
9335       JNI function can be called after the data is collected.
9336       Note also that any JNI functions which are not overwritten
9337       will behave normally.
9338       <todo>
9339         check that the example compiles and executes.
9340       </todo>
9341     </intro>
9342 
9343     <function id="SetJNIFunctionTable" phase="start" num="120">
9344       <synopsis>Set JNI Function Table</synopsis>
9345       <description>
9346         Set the JNI function table
9347         in all current and future JNI environments.
9348         As a result, all future JNI calls are directed to the specified functions.
9349         Use <functionlink id="GetJNIFunctionTable"></functionlink> to get the
9350         function table to pass to this function.
9351         For this function to take effect the the updated table entries must be
9352         used by the JNI clients.
9353         Since the table is defined <code>const</code> some compilers may optimize
9354         away the access to the table, thus preventing this function from taking
9355         effect.
9356         The table is copied--changes to the local copy of the
9357         table have no effect.
9358         This function affects only the function table, all other aspects of the environment are
9359         unaffected.
9360         See the examples <internallink id="jniIntercept">above</internallink>.
9361       </description>
9362       <origin>new</origin>
9363       <capabilities>
9364       </capabilities>
9365       <parameters>
9366         <param id="function_table">
9367           <inptr>
9368             <struct>jniNativeInterface</struct>
9369           </inptr>
9370           <description>
9371             Points to the new JNI function table.
9372           </description>
9373         </param>
9374       </parameters>
9375       <errors>
9376       </errors>
9377     </function>
9378 
9379     <function id="GetJNIFunctionTable" phase="start" num="121">
9380       <synopsis>Get JNI Function Table</synopsis>
9381       <description>
9382         Get the JNI function table.
9383         The JNI function table is copied into allocated memory.
9384         If <functionlink id="SetJNIFunctionTable"></functionlink>
9385         has been called, the modified (not the original) function
9386         table is returned.
9387         Only the function table is copied, no other aspects of the environment
9388         are copied.
9389         See the examples <internallink id="jniIntercept">above</internallink>.
9390       </description>
9391       <origin>new</origin>
9392       <capabilities>
9393       </capabilities>
9394       <parameters>
9395         <param id="function_table">
9396           <allocbuf>
9397             <struct>jniNativeInterface</struct>
9398           </allocbuf>
9399           <description>
9400             On return, <code>*function_table</code>
9401             points a newly allocated copy of the JNI function table.
9402           </description>
9403         </param>
9404       </parameters>
9405       <errors>
9406       </errors>
9407     </function>
9408 
9409   </category>
9410 
9411   <category id="eventManagement" label="Event Management">
9412 
9413     <function id="SetEventCallbacks" jkernel="yes" phase="onload" num="122">
9414       <synopsis>Set Event Callbacks</synopsis>
9415       <description>
9416         Set the functions to be called for each event.
9417         The callbacks are specified by supplying a replacement function table.
9418         The function table is copied--changes to the local copy of the
9419         table have no effect.
9420         This is an atomic action, all callbacks are set at once.
9421         No events are sent before this function is called.
9422         When an entry is <code>NULL</code> or when the event is beyond
9423         <paramlink id="size_of_callbacks"></paramlink> no event is sent.
9424         Details on events are
9425         described <internallink id="EventSection">later</internallink> in this document.
9426         An event must be enabled and have a callback in order to be
9427         sent--the order in which this function and
9428         <functionlink id="SetEventNotificationMode"></functionlink>
9429         are called does not affect the result.
9430       </description>
9431       <origin>new</origin>
9432       <capabilities>
9433       </capabilities>
9434       <parameters>
9435         <param id="callbacks">
9436           <inptr>
9437             <struct>jvmtiEventCallbacks</struct>
9438             <nullok>remove the existing callbacks</nullok>
9439           </inptr>
9440           <description>
9441             The new event callbacks.
9442           </description>
9443         </param>
9444         <param id="size_of_callbacks">
9445           <jint min="0"/>
9446           <description>
9447             <code>sizeof(jvmtiEventCallbacks)</code>--for version
9448             compatibility.
9449           </description>
9450         </param>
9451       </parameters>
9452       <errors>
9453       </errors>
9454     </function>
9455 
9456     <function id="SetEventNotificationMode" jkernel="yes" phase="onload" num="2">
9457       <synopsis>Set Event Notification Mode</synopsis>
9458       <description>
9459         Control the generation of events.
9460         <constants id="jvmtiEventMode" label="Event Enable/Disable" kind="enum">
9461           <constant id="JVMTI_ENABLE" num="1">
9462             If <paramlink id="mode"></paramlink> is <code>JVMTI_ENABLE</code>,
9463             the event <paramlink id="event_type"></paramlink> will be enabled
9464           </constant>
9465           <constant id="JVMTI_DISABLE" num="0">
9466             If <paramlink id="mode"></paramlink> is <code>JVMTI_DISABLE</code>,
9467             the event <paramlink id="event_type"></paramlink> will be disabled
9468           </constant>
9469         </constants>
9470         If <code>event_thread</code> is <code>NULL</code>,
9471         the event is enabled or disabled globally; otherwise, it is
9472         enabled or disabled for a particular thread.
9473         An event is generated for
9474         a particular thread if it is enabled either at the thread or global
9475         levels.
9476         <p/>
9477         See <internallink id="EventIndex">below</internallink> for information on specific events.
9478         <p/>
9479         The following events cannot be controlled at the thread
9480         level through this function.
9481         <ul>
9482           <li><eventlink id="VMInit"></eventlink></li>
9483           <li><eventlink id="VMStart"></eventlink></li>
9484           <li><eventlink id="VMDeath"></eventlink></li>
9485           <li><eventlink id="ThreadStart"></eventlink></li>
9486           <li><eventlink id="CompiledMethodLoad"></eventlink></li>
9487           <li><eventlink id="CompiledMethodUnload"></eventlink></li>
9488           <li><eventlink id="DynamicCodeGenerated"></eventlink></li>
9489           <li><eventlink id="DataDumpRequest"></eventlink></li>
9490         </ul>
9491         <p/>
9492         Initially, no events are enabled at either the thread level
9493         or the global level.
9494         <p/>
9495         Any needed capabilities (see Event Enabling Capabilities below) must be possessed
9496         before calling this function.
9497         <p/>
9498         Details on events are
9499         described <internallink id="EventSection">below</internallink>.
9500       </description>
9501       <origin>jvmdiClone</origin>
9502       <eventcapabilities></eventcapabilities>
9503       <parameters>
9504         <param id="mode">
9505           <enum>jvmtiEventMode</enum>
9506           <description>
9507             <code>JVMTI_ENABLE</code> or <code>JVMTI_DISABLE</code>
9508           </description>
9509         </param>
9510         <param id="event_type">
9511           <enum>jvmtiEvent</enum>
9512           <description>
9513             the event to control
9514           </description>
9515         </param>
9516         <param id="event_thread">
9517           <ptrtype>
9518             <jthread impl="noconvert"/>
9519             <nullok>event is controlled at the global level</nullok>
9520           </ptrtype>
9521             <description>
9522               The thread to control
9523             </description>
9524         </param>
9525         <param id="...">
9526           <varargs/>
9527             <description>
9528               for future expansion
9529             </description>
9530         </param>
9531       </parameters>
9532       <errors>
9533         <error id="JVMTI_ERROR_INVALID_THREAD">
9534           <paramlink id="event_thread"/> is non-<code>NULL</code> and is not a valid thread.
9535         </error>
9536         <error id="JVMTI_ERROR_THREAD_NOT_ALIVE">
9537           <paramlink id="event_thread"/> is non-<code>NULL</code> and is not live (has not been started or is now dead).
9538         </error>
9539         <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
9540           thread level control was attempted on events which do not
9541           permit thread level control.
9542         </error>
9543         <error id="JVMTI_ERROR_MUST_POSSESS_CAPABILITY">
9544           The Required Event Enabling Capability is not possessed.
9545         </error>
9546       </errors>
9547     </function>
9548 
9549     <function id="GenerateEvents" num="123">
9550       <synopsis>Generate Events</synopsis>
9551       <description>
9552         Generate events to represent the current state of the VM.
9553         For example, if <paramlink id="event_type"/> is
9554         <code>JVMTI_EVENT_COMPILED_METHOD_LOAD</code>,
9555         a <eventlink id="CompiledMethodLoad"></eventlink> event will be
9556         sent for each currently compiled method.
9557         Methods that were loaded and now have been unloaded are not sent.
9558         The history of what events have previously been sent does not
9559         effect what events are sent by this function--for example,
9560         all currently compiled methods
9561         will be sent each time this function is called.
9562         <p/>
9563         This function is useful when
9564         events may have been missed due to the agent attaching after program
9565         execution begins; this function generates the missed events.
9566         <p/>
9567         Attempts to execute Java programming language code or
9568         JNI functions may be paused until this function returns -
9569         so neither should be called from the thread sending the event.
9570         This function returns only after the missed events have been
9571         sent, processed and have returned.
9572         The event may be sent on a different thread than the thread
9573         on which the event occurred.
9574         The callback for the event must be set with
9575         <functionlink id="SetEventCallbacks"></functionlink>
9576         and the event must be enabled with
9577         <functionlink id="SetEventNotificationMode"></functionlink>
9578         or the events will not occur.
9579         If the VM no longer has the information to generate some or
9580         all of the requested events, the events are simply not sent -
9581         no error is returned.
9582         <p/>
9583         Only the following events are supported:
9584         <ul>
9585           <li><eventlink id="CompiledMethodLoad"></eventlink></li>
9586           <li><eventlink id="DynamicCodeGenerated"></eventlink></li>
9587         </ul>
9588       </description>
9589       <origin>new</origin>
9590       <capabilities>
9591         <capability id="can_generate_compiled_method_load_events"></capability>
9592       </capabilities>
9593       <parameters>
9594         <param id="event_type">
9595           <enum>jvmtiEvent</enum>
9596           <description>
9597             The type of event to generate.  Must be one of these:
9598             <ul>
9599               <li><eventlink id="CompiledMethodLoad"><code>JVMTI_EVENT_COMPILED_METHOD_LOAD</code></eventlink></li>
9600               <li><eventlink id="DynamicCodeGenerated"><code>JVMTI_EVENT_DYNAMIC_CODE_GENERATED</code></eventlink></li>
9601             </ul>
9602           </description>
9603         </param>
9604       </parameters>
9605       <errors>
9606         <error id="JVMTI_ERROR_MUST_POSSESS_CAPABILITY">
9607           <paramlink id="event_type"/> is
9608           <eventlink id="CompiledMethodLoad"><code>JVMTI_EVENT_COMPILED_METHOD_LOAD</code></eventlink>
9609           and <fieldlink id="can_generate_compiled_method_load_events" struct="jvmtiCapabilities"></fieldlink>
9610           is <code>false</code>.
9611         </error>
9612         <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
9613           <paramlink id="event_type"/> is other than
9614           <eventlink id="CompiledMethodLoad"><code>JVMTI_EVENT_COMPILED_METHOD_LOAD</code></eventlink>
9615           or <eventlink id="DynamicCodeGenerated"><code>JVMTI_EVENT_DYNAMIC_CODE_GENERATED</code></eventlink>.
9616         </error>
9617       </errors>
9618     </function>
9619 
9620   </category>
9621 
9622     <category id="extension" label="Extension Mechanism">
9623 
9624       <intro>
9625         These functions
9626         allow a <jvmti/> implementation to provide functions and events
9627         beyond those defined in this specification.
9628         <p/>
9629         Both extension functions and extension events have parameters
9630         each of which has a 'type' and 'kind' chosen from the following tables:
9631 
9632         <constants id="jvmtiParamTypes" label="Extension Function/Event Parameter Types" kind="enum">
9633           <constant id="JVMTI_TYPE_JBYTE" num="101">
9634             Java programming language primitive type - <code>byte</code>.
9635             JNI type <code>jbyte</code>.
9636           </constant>
9637           <constant id="JVMTI_TYPE_JCHAR" num="102">
9638             Java programming language primitive type - <code>char</code>.
9639             JNI type <code>jchar</code>.
9640           </constant>
9641           <constant id="JVMTI_TYPE_JSHORT" num="103">
9642             Java programming language primitive type - <code>short</code>.
9643             JNI type <code>jshort</code>.
9644           </constant>
9645           <constant id="JVMTI_TYPE_JINT" num="104">
9646             Java programming language primitive type - <code>int</code>.
9647             JNI type <datalink id="jint"></datalink>.
9648           </constant>
9649           <constant id="JVMTI_TYPE_JLONG" num="105">
9650             Java programming language primitive type - <code>long</code>.
9651             JNI type <datalink id="jlong"></datalink>.
9652           </constant>
9653           <constant id="JVMTI_TYPE_JFLOAT" num="106">
9654             Java programming language primitive type - <code>float</code>.
9655             JNI type <datalink id="jfloat"></datalink>.
9656           </constant>
9657           <constant id="JVMTI_TYPE_JDOUBLE" num="107">
9658             Java programming language primitive type - <code>double</code>.
9659             JNI type <datalink id="jdouble"></datalink>.
9660           </constant>
9661           <constant id="JVMTI_TYPE_JBOOLEAN" num="108">
9662             Java programming language primitive type - <code>boolean</code>.
9663             JNI type <datalink id="jboolean"></datalink>.
9664           </constant>
9665           <constant id="JVMTI_TYPE_JOBJECT" num="109">
9666             Java programming language object type - <code>java.lang.Object</code>.
9667             JNI type <datalink id="jobject"></datalink>.
9668             Returned values are JNI local references and must be managed.
9669           </constant>
9670           <constant id="JVMTI_TYPE_JTHREAD" num="110">
9671             Java programming language object type - <code>java.lang.Thread</code>.
9672             <jvmti/> type <datalink id="jthread"></datalink>.
9673             Returned values are JNI local references and must be managed.
9674           </constant>
9675           <constant id="JVMTI_TYPE_JCLASS" num="111">
9676             Java programming language object type - <code>java.lang.Class</code>.
9677             JNI type <datalink id="jclass"></datalink>.
9678             Returned values are JNI local references and must be managed.
9679           </constant>
9680           <constant id="JVMTI_TYPE_JVALUE" num="112">
9681             Union of all Java programming language primitive and object types -
9682             JNI type <datalink id="jvalue"></datalink>.
9683             Returned values which represent object types are JNI local references and must be managed.
9684           </constant>
9685           <constant id="JVMTI_TYPE_JFIELDID" num="113">
9686             Java programming language field identifier -
9687             JNI type <datalink id="jfieldID"></datalink>.
9688           </constant>
9689           <constant id="JVMTI_TYPE_JMETHODID" num="114">
9690             Java programming language method identifier -
9691             JNI type <datalink id="jmethodID"></datalink>.
9692           </constant>
9693           <constant id="JVMTI_TYPE_CCHAR" num="115">
9694             C programming language type - <code>char</code>.
9695           </constant>
9696           <constant id="JVMTI_TYPE_CVOID" num="116">
9697             C programming language type - <code>void</code>.
9698           </constant>
9699           <constant id="JVMTI_TYPE_JNIENV" num="117">
9700             JNI environment - <code>JNIEnv</code>.
9701             Should be used with the correct <datalink id="jvmtiParamKind"/> to make it a pointer type.
9702           </constant>
9703         </constants>
9704 
9705         <constants id="jvmtiParamKind" label="Extension Function/Event Parameter Kinds" kind="enum">
9706           <constant id="JVMTI_KIND_IN" num="91">
9707             Ingoing argument - <code>foo</code>.
9708           </constant>
9709           <constant id="JVMTI_KIND_IN_PTR" num="92">
9710             Ingoing pointer argument - <code>const foo*</code>.
9711           </constant>
9712           <constant id="JVMTI_KIND_IN_BUF" num="93">
9713             Ingoing array argument - <code>const foo*</code>.
9714           </constant>
9715           <constant id="JVMTI_KIND_ALLOC_BUF" num="94">
9716             Outgoing allocated array argument -  <code>foo**</code>.
9717             Free with <code>Deallocate</code>.
9718           </constant>
9719           <constant id="JVMTI_KIND_ALLOC_ALLOC_BUF" num="95">
9720             Outgoing allocated array of allocated arrays argument - <code>foo***</code>.
9721             Free with <code>Deallocate</code>.
9722           </constant>
9723           <constant id="JVMTI_KIND_OUT" num="96">
9724             Outgoing argument - <code>foo*</code>.
9725           </constant>
9726           <constant id="JVMTI_KIND_OUT_BUF" num="97">
9727             Outgoing array argument (pre-allocated by agent) - <code>foo*</code>.
9728             Do not <code>Deallocate</code>.
9729           </constant>
9730         </constants>
9731 
9732       </intro>
9733 
9734       <typedef id="jvmtiParamInfo" label="Extension Function/Event Parameter Info">
9735         <field id="name">
9736           <allocfieldbuf><char/></allocfieldbuf>
9737             <description>
9738               The parameter name, encoded as a
9739               <internallink id="mUTF">modified UTF-8</internallink> string
9740             </description>
9741         </field>
9742         <field id="kind">
9743           <enum>jvmtiParamKind</enum>
9744           <description>
9745             The kind of the parameter - type modifiers
9746           </description>
9747         </field>
9748         <field id="base_type">
9749           <enum>jvmtiParamTypes</enum>
9750           <description>
9751             The base type of the parameter -  modified by <code>kind</code>
9752           </description>
9753         </field>
9754         <field id="null_ok">
9755           <jboolean/>
9756             <description>
9757               Is a <code>NULL</code> argument permitted? Applies only to pointer and object types.
9758             </description>
9759         </field>
9760       </typedef>
9761 
9762       <callback id="jvmtiExtensionFunction">
9763         <enum>jvmtiError</enum>
9764           <synopsis>Extension Function</synopsis>
9765         <description>
9766           This is the implementation-specific extension function.
9767         </description>
9768         <parameters>
9769           <param id="jvmti_env">
9770             <outptr>
9771               <struct>jvmtiEnv</struct>
9772             </outptr>
9773             <description>
9774               The <jvmti/> environment is the only fixed parameter for extension functions.
9775             </description>
9776           </param>
9777           <param id="...">
9778             <varargs/>
9779               <description>
9780                 The extension function-specific parameters
9781               </description>
9782           </param>
9783         </parameters>
9784       </callback>
9785 
9786       <function id="GetExtensionFunctions" phase="onload" num="124">
9787         <synopsis>Get Extension Functions</synopsis>
9788 
9789         <typedef id="jvmtiExtensionFunctionInfo" label="Extension Function Info">
9790           <field id="func">
9791             <ptrtype>
9792               <struct>jvmtiExtensionFunction</struct>
9793             </ptrtype>
9794             <description>
9795               The actual function to call
9796             </description>
9797           </field>
9798           <field id="id">
9799             <allocfieldbuf><char/></allocfieldbuf>
9800               <description>
9801                 The identifier for the extension function, encoded as a
9802                 <internallink id="mUTF">modified UTF-8</internallink> string.
9803                 Uses package name conventions.
9804                 For example, <code>com.sun.hotspot.bar</code>
9805               </description>
9806           </field>
9807           <field id="short_description">
9808             <allocfieldbuf><char/></allocfieldbuf>
9809               <description>
9810                 A one sentence description of the function, encoded as a
9811                 <internallink id="mUTF">modified UTF-8</internallink> string.
9812               </description>
9813           </field>
9814           <field id="param_count">
9815             <jint/>
9816               <description>
9817                 The number of parameters excluding <code>jvmtiEnv *jvmti_env</code>
9818               </description>
9819           </field>
9820           <field id="params">
9821             <allocfieldbuf outcount="param_count">
9822               <struct>jvmtiParamInfo</struct>
9823             </allocfieldbuf>
9824             <description>
9825               Array of
9826               <fieldlink id="param_count" struct="jvmtiExtensionFunctionInfo"></fieldlink>
9827               parameters (<code>jvmtiEnv *jvmti_env</code> excluded)
9828             </description>
9829           </field>
9830           <field id="error_count">
9831             <jint/>
9832               <description>
9833                 The number of possible error returns (excluding universal errors)
9834               </description>
9835           </field>
9836           <field id="errors">
9837             <allocfieldbuf outcount="error_count">
9838               <enum>jvmtiError</enum>
9839             </allocfieldbuf>
9840             <description>
9841               Array of <fieldlink id="error_count" struct="jvmtiExtensionFunctionInfo"></fieldlink>
9842               possible errors
9843             </description>
9844           </field>
9845         </typedef>
9846 
9847         <description>
9848           Returns the set of extension functions.
9849         </description>
9850         <origin>new</origin>
9851         <capabilities>
9852         </capabilities>
9853         <parameters>
9854           <param id="extension_count_ptr">
9855             <outptr><jint/></outptr>
9856               <description>
9857                 On return, points to the number of extension functions
9858               </description>
9859           </param>
9860           <param id="extensions">
9861             <allocbuf outcount="extension_count_ptr"><struct>jvmtiExtensionFunctionInfo</struct></allocbuf>
9862             <description>
9863               Returns an array of extension function info, one per function
9864             </description>
9865           </param>
9866         </parameters>
9867         <errors>
9868         </errors>
9869       </function>
9870 
9871       <function id="GetExtensionEvents" phase="onload" num="125">
9872         <synopsis>Get Extension Events</synopsis>
9873 
9874         <typedef id="jvmtiExtensionEventInfo" label="Extension Event Info">
9875           <field id="extension_event_index">
9876             <jint/>
9877             <description>
9878               The identifying index of the event
9879             </description>
9880           </field>
9881           <field id="id">
9882             <allocfieldbuf><char/></allocfieldbuf>
9883               <description>
9884                 The identifier for the extension event, encoded as a
9885                 <internallink id="mUTF">modified UTF-8</internallink> string.
9886                 Uses package name conventions.
9887                 For example, <code>com.sun.hotspot.bar</code>
9888               </description>
9889           </field>
9890           <field id="short_description">
9891             <allocfieldbuf><char/></allocfieldbuf>
9892               <description>
9893                 A one sentence description of the event, encoded as a
9894                 <internallink id="mUTF">modified UTF-8</internallink> string.
9895               </description>
9896           </field>
9897           <field id="param_count">
9898             <jint/>
9899               <description>
9900                 The number of parameters excluding <code>jvmtiEnv *jvmti_env</code>
9901               </description>
9902           </field>
9903           <field id="params">
9904             <allocfieldbuf outcount="param_count">
9905               <struct>jvmtiParamInfo</struct>
9906             </allocfieldbuf>
9907             <description>
9908               Array of
9909               <fieldlink id="param_count" struct="jvmtiExtensionEventInfo"></fieldlink>
9910               parameters (<code>jvmtiEnv *jvmti_env</code> excluded)
9911             </description>
9912           </field>
9913         </typedef>
9914 
9915         <description>
9916           Returns the set of extension events.
9917         </description>
9918         <origin>new</origin>
9919         <capabilities>
9920         </capabilities>
9921         <parameters>
9922           <param id="extension_count_ptr">
9923             <outptr><jint/></outptr>
9924               <description>
9925                 On return, points to the number of extension events
9926               </description>
9927           </param>
9928           <param id="extensions">
9929             <allocbuf outcount="extension_count_ptr"><struct>jvmtiExtensionEventInfo</struct></allocbuf>
9930             <description>
9931               Returns an array of extension event info, one per event
9932             </description>
9933           </param>
9934         </parameters>
9935         <errors>
9936         </errors>
9937       </function>
9938 
9939       <callback id="jvmtiExtensionEvent">
9940         <void/>
9941           <synopsis>Extension Event</synopsis>
9942         <description>
9943           This is the implementation-specific event.
9944           The event handler is set with
9945           <functionlink id="SetExtensionEventCallback"/>.
9946           <p/>
9947           Event handlers for extension events must be declared varargs to match this definition.
9948           Failure to do so could result in calling convention mismatch and undefined behavior
9949           on some platforms.
9950           <p/>
9951           For example, if the <code>jvmtiParamInfo</code>
9952           returned by <functionlink id="GetExtensionEvents"/> indicates that
9953           there is a <code>jint</code> parameter, the event handler should be
9954           declared:
9955 <example>
9956     void JNICALL myHandler(jvmtiEnv* jvmti_env, jint myInt, ...)
9957 </example>
9958           Note the terminal "<code>...</code>" which indicates varargs.
9959         </description>
9960         <parameters>
9961           <param id="jvmti_env">
9962             <outptr>
9963               <struct>jvmtiEnv</struct>
9964             </outptr>
9965             <description>
9966               The <jvmti/> environment is the only fixed parameter for extension events.
9967             </description>
9968           </param>
9969           <param id="...">
9970             <varargs/>
9971               <description>
9972                 The extension event-specific parameters
9973               </description>
9974           </param>
9975         </parameters>
9976       </callback>
9977 
9978       <function id="SetExtensionEventCallback" phase="onload" num="126">
9979         <synopsis>Set Extension Event Callback</synopsis>
9980 
9981         <description>
9982           Sets the callback function for an extension event and
9983           enables the event. Or, if the callback is <code>NULL</code>, disables
9984           the event.  Note that unlike standard events, setting
9985           the callback and enabling the event are a single operation.
9986         </description>
9987         <origin>new</origin>
9988         <capabilities>
9989         </capabilities>
9990         <parameters>
9991           <param id="extension_event_index">
9992             <jint/>
9993               <description>
9994                 Identifies which callback to set.
9995                 This index is the
9996                 <fieldlink id="extension_event_index" struct="jvmtiExtensionEventInfo"></fieldlink>
9997                 field of
9998                 <datalink id="jvmtiExtensionEventInfo"/>.
9999               </description>
10000           </param>
10001           <param id="callback">
10002             <ptrtype>
10003               <struct>jvmtiExtensionEvent</struct>
10004               <nullok>disable the event</nullok>
10005             </ptrtype>
10006             <description>
10007               If <code>callback</code> is non-<code>NULL</code>,
10008               set <code>callback</code> to be the event callback function
10009               and enable the event.
10010             </description>
10011           </param>
10012         </parameters>
10013         <errors>
10014         <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
10015             <paramlink id="extension_event_index"/> is not an
10016             <fieldlink id="extension_event_index"
10017                        struct="jvmtiExtensionEventInfo"/>
10018             returned by
10019             <functionlink id="GetExtensionEvents"/>
10020         </error>
10021         </errors>
10022       </function>
10023 
10024     </category>
10025 
10026   <category id="capability" label="Capability">
10027 
10028     <intro>
10029       The capabilities functions allow you to change the
10030       functionality available to <jvmti/>--that is,
10031       which <jvmti/>
10032       functions can be called, what events can be generated,
10033       and what functionality these events and functions can
10034       provide.
10035       <p/>
10036         The "Capabilities" section of each function and event describe which
10037         capabilities, if any, they are associated with. "Required Functionality"
10038         means it is available for use and no capabilities must be added to use it.
10039         "Optional Functionality" means the agent must possess the capability
10040         before it can be used.
10041         To possess a capability, the agent must
10042         <functionlink id="AddCapabilities">add the capability</functionlink>.
10043         "Optional Features" describe capabilities which,
10044         if added, extend the feature set.
10045         <p/>
10046         The potentially available capabilities of each <jvmti/> implementation are different.
10047         Depending on the implementation, a capability:
10048         <ul>
10049           <li>may never be added</li>
10050           <li>may be added in either the <code>OnLoad</code> or live phase in any environment</li>
10051           <li>may be added only during the <code>OnLoad</code> phase</li>
10052           <li>may be possessed by only one environment at a time</li>
10053           <li>may be possessed by only one environment at a time,
10054               and only during the <code>OnLoad</code> phase</li>
10055           <li>and so on ...</li>
10056         </ul>
10057       Frequently, the addition of a capability may incur a cost in execution speed, start up
10058       time, and/or memory footprint.  Note that the overhead of using a capability
10059       is completely different than the overhead of possessing a capability.
10060       Take single stepping as an example. When single stepping is on (that
10061       is, when the event is enabled and thus actively sending events)
10062       the overhead of sending and processing an event
10063       on each instruction is huge in any implementation.
10064       However, the overhead of possessing the capability may be small or large,
10065       depending on the implementation.  Also, when and if a capability is potentially
10066       available depends on the implementation.  Some examples:
10067       <ul>
10068         <li>One VM might perform all execution by compiling bytecodes into
10069           native code and be unable to generate single step instructions.
10070           In this implementation the capability can not be added.</li>
10071         <li>Another VM may be able to switch execution to a single stepping
10072           interpreter at any time.  In this implementation, having the capability has no
10073           overhead and could be added at any time.</li>
10074         <li>Yet another VM might be able to choose a bytecode compiling or single stepping capable interpreted
10075           execution engine at start up, but be unable to switch between them.
10076           In this implementation the capability would need to be added
10077           during the <code>OnLoad</code> phase (before bytecode
10078           execution begins) and would have a large impact on execution speed
10079           even if single stepping was never used.</li>
10080         <li>Still another VM might be able to add an "is single stepping on" check
10081           into compiled bytecodes or a generated interpreter.  Again in this implementation
10082           the capability would need to be added during the <code>OnLoad</code> phase but the overhead (a test
10083           and branch on each instruction) would be considerably less.</li>
10084       </ul>
10085       <p/>
10086       Each <jvmti/> <internallink id="environments">environment</internallink>
10087       has its own set of capabilities.
10088       Initially, that set is empty.
10089       Any desired capability must be added.
10090       If possible, capabilities should be added during the <code>OnLoad</code> phase.  For most
10091       virtual machines certain capabilities require special set up for
10092       the virtual machine and this set up must happen
10093       during the <code>OnLoad</code> phase, before the virtual machine begins execution.
10094       Once a capability is added, it can
10095       only be removed if explicitly relinquished by the environment.
10096       <p/>
10097       The agent can,
10098       <functionlink id="GetPotentialCapabilities">determine what
10099         capabilities this VM can potentially provide</functionlink>,
10100       <functionlink id="AddCapabilities">add the capabilities
10101         to be used</functionlink>,
10102       <functionlink id="RelinquishCapabilities">release capabilities
10103         which are no longer needed</functionlink>, and
10104       <functionlink id="GetCapabilities">examine the currently available
10105         capabilities</functionlink>.
10106     </intro>
10107 
10108     <intro id="capabilityExamples" label="Capability Examples">
10109       For example, a freshly started agent (in the <code>OnLoad</code> function)
10110       wants to enable all possible capabilities.
10111       Note that, in general, this is not advisable as the agent may suffer
10112       a performance penalty for functionality it is not using.
10113       The code might look like this in C:
10114       <example>
10115         jvmtiCapabilities capa;
10116         jvmtiError err;
10117 
10118         err = (*jvmti)-&gt;GetPotentialCapabilities(jvmti, &amp;capa);
10119         if (err == JVMTI_ERROR_NONE) {
10120            err = (*jvmti)-&gt;AddCapabilities(jvmti, &amp;capa);
10121       </example>
10122       For example, if an  agent wants to check if it can get
10123       the bytecodes of a method (that is, it wants to check
10124       if it previously added this capability and has not
10125       relinquished it), the code might
10126       look like this in C:
10127       <example>
10128         jvmtiCapabilities capa;
10129         jvmtiError err;
10130 
10131         err = (*jvmti)-&gt;GetCapabilities(jvmti, &amp;capa);
10132         if (err == JVMTI_ERROR_NONE) {
10133            if (capa.can_get_bytecodes) { ... } }
10134       </example>
10135     </intro>
10136 
10137     <capabilitiestypedef id="jvmtiCapabilities" label="The Capabilities Structure">
10138       <description>
10139         The functions in this category use this capabilities structure
10140         which contains boolean flags corresponding to each capability:
10141       </description>
10142       <capabilityfield id="can_tag_objects">
10143         <description>
10144           Can set and get tags, as described in the
10145           <internallink id="Heap">Heap category</internallink>.
10146         </description>
10147       </capabilityfield>
10148       <capabilityfield id="can_generate_field_modification_events">
10149         <description>
10150           Can set watchpoints on field modification -
10151           <functionlink id="SetFieldModificationWatch"></functionlink>
10152         </description>
10153       </capabilityfield>
10154       <capabilityfield id="can_generate_field_access_events">
10155         <description>
10156           Can set watchpoints on field access -
10157           <functionlink id="SetFieldAccessWatch"></functionlink>
10158         </description>
10159       </capabilityfield>
10160       <capabilityfield id="can_get_bytecodes">
10161         <description>
10162           Can get bytecodes of a method <functionlink id="GetBytecodes"></functionlink>
10163         </description>
10164       </capabilityfield>
10165       <capabilityfield id="can_get_synthetic_attribute">
10166         <description>
10167           Can test if a field or method is synthetic -
10168           <functionlink id="IsFieldSynthetic"></functionlink> and
10169           <functionlink id="IsMethodSynthetic"></functionlink>
10170         </description>
10171       </capabilityfield>
10172       <capabilityfield id="can_get_owned_monitor_info">
10173         <description>
10174           Can get information about ownership of monitors -
10175           <functionlink id="GetOwnedMonitorInfo"></functionlink>
10176         </description>
10177       </capabilityfield>
10178       <capabilityfield id="can_get_current_contended_monitor">
10179         <description>
10180           Can <functionlink id="GetCurrentContendedMonitor"></functionlink>
10181         </description>
10182       </capabilityfield>
10183       <capabilityfield id="can_get_monitor_info">
10184       <description>
10185         Can <functionlink id="GetObjectMonitorUsage"></functionlink>
10186       </description>
10187       </capabilityfield>
10188       <capabilityfield id="can_pop_frame">
10189         <description>
10190           Can pop frames off the stack - <functionlink id="PopFrame"></functionlink>
10191         </description>
10192       </capabilityfield>
10193       <capabilityfield id="can_redefine_classes">
10194         <description>
10195           Can redefine classes with <functionlink id="RedefineClasses"/>.
10196         </description>
10197       </capabilityfield>
10198       <capabilityfield id="can_signal_thread">
10199         <description>
10200           Can send stop or interrupt to threads
10201         </description>
10202       </capabilityfield>
10203       <capabilityfield id="can_get_source_file_name">
10204         <description>
10205           Can get the source file name of a class
10206         </description>
10207       </capabilityfield>
10208       <capabilityfield id="can_get_line_numbers">
10209         <description>
10210           Can get the line number table of a method
10211         </description>
10212       </capabilityfield>
10213       <capabilityfield id="can_get_source_debug_extension">
10214         <description>
10215           Can get the source debug extension of a class
10216         </description>
10217       </capabilityfield>
10218       <capabilityfield id="can_access_local_variables">
10219         <description>
10220           Can set and get local variables
10221         </description>
10222       </capabilityfield>
10223       <capabilityfield id="can_maintain_original_method_order">
10224         <description>
10225           Can return methods in the order they occur in the class file
10226         </description>
10227       </capabilityfield>
10228       <capabilityfield id="can_generate_single_step_events">
10229         <description>
10230           Can get <eventlink id="SingleStep">single step</eventlink> events
10231         </description>
10232       </capabilityfield>
10233       <capabilityfield id="can_generate_exception_events">
10234         <description>
10235           Can get <eventlink id="Exception">exception thrown</eventlink> and
10236             <eventlink id="ExceptionCatch">exception catch</eventlink> events
10237         </description>
10238       </capabilityfield>
10239       <capabilityfield id="can_generate_frame_pop_events">
10240         <description>
10241           Can <functionlink id="NotifyFramePop">set</functionlink> and thus get
10242             <eventlink id="FramePop"></eventlink> events
10243         </description>
10244       </capabilityfield>
10245       <capabilityfield id="can_generate_breakpoint_events">
10246         <description>
10247           Can <functionlink id="SetBreakpoint">set</functionlink> and thus get
10248             <eventlink id="Breakpoint"></eventlink> events
10249         </description>
10250       </capabilityfield>
10251       <capabilityfield id="can_suspend">
10252         <description>
10253           Can suspend and resume threads
10254         </description>
10255       </capabilityfield>
10256       <capabilityfield id="can_redefine_any_class">
10257         <description>
10258           <functionlink id="RedefineClasses"/> can be called on any modifiable class.
10259           See <functionlink id="IsModifiableClass"/>.
10260           (<fieldlink id="can_redefine_classes" struct="jvmtiCapabilities"/>
10261           must also be set)
10262         </description>
10263       </capabilityfield>
10264       <capabilityfield id="can_get_current_thread_cpu_time">
10265         <description>
10266           Can <functionlink id="GetCurrentThreadCpuTime">get</functionlink>
10267           current thread CPU time
10268         </description>
10269       </capabilityfield>
10270       <capabilityfield id="can_get_thread_cpu_time">
10271         <description>
10272           Can <functionlink id="GetThreadCpuTime">get</functionlink>
10273           thread CPU time
10274         </description>
10275       </capabilityfield>
10276       <capabilityfield id="can_generate_method_entry_events"
10277                        disp1="can_generate" disp2="_method_entry_events"
10278                        >
10279         <description>
10280           Can generate method entry events on entering a method
10281         </description>
10282       </capabilityfield>
10283       <capabilityfield id="can_generate_method_exit_events"
10284                        disp1="can_generate" disp2="_method_exit_events"
10285                        >
10286         <description>
10287           Can generate method exit events on leaving a method
10288         </description>
10289       </capabilityfield>
10290       <capabilityfield id="can_generate_all_class_hook_events"
10291                        disp1="can_generate" disp2="_all_class_hook_events"
10292                        >
10293         <description>
10294           Can generate ClassFileLoadHook events for every loaded class.
10295         </description>
10296       </capabilityfield>
10297       <capabilityfield id="can_generate_compiled_method_load_events"
10298                        disp1="can_generate" disp2="_compiled_method_load_events"
10299                        >
10300         <description>
10301           Can generate events when a method is compiled or unloaded
10302         </description>
10303       </capabilityfield>
10304       <capabilityfield id="can_generate_monitor_events"
10305                        disp1="can_generate" disp2="_monitor_events"
10306                        >
10307         <description>
10308           Can generate events on monitor activity
10309         </description>
10310       </capabilityfield>
10311       <capabilityfield id="can_generate_vm_object_alloc_events"
10312                        disp1="can_generate" disp2="_vm_object_alloc_events"
10313                        >
10314         <description>
10315           Can generate events on VM allocation of an object
10316         </description>
10317       </capabilityfield>
10318       <capabilityfield id="can_generate_native_method_bind_events"
10319                        disp1="can_generate" disp2="_native_method_bind_events"
10320                        >
10321         <description>
10322           Can generate events when a native method is bound to its
10323           implementation
10324         </description>
10325       </capabilityfield>
10326       <capabilityfield id="can_generate_garbage_collection_events"
10327                        disp1="can_generate" disp2="_garbage_collection_events"
10328                        >
10329         <description>
10330           Can generate events when garbage collection begins or ends
10331         </description>
10332       </capabilityfield>
10333       <capabilityfield id="can_generate_object_free_events"
10334                        disp1="can_generate" disp2="_object_free_events"
10335                        >
10336         <description>
10337           Can generate events when the garbage collector frees an object
10338         </description>
10339       </capabilityfield>
10340       <capabilityfield id="can_force_early_return" since="1.1">
10341         <description>
10342           Can return early from a method, as described in the
10343           <internallink id="ForceEarlyReturn">Force Early Return category</internallink>.
10344         </description>
10345       </capabilityfield>
10346       <capabilityfield id="can_get_owned_monitor_stack_depth_info" since="1.1">
10347         <description>
10348           Can get information about owned monitors with stack depth -
10349           <functionlink id="GetOwnedMonitorStackDepthInfo"></functionlink>
10350         </description>
10351       </capabilityfield>
10352       <capabilityfield id="can_get_constant_pool" since="1.1">
10353         <description>
10354           Can get the constant pool of a class -
10355           <functionlink id="GetConstantPool"></functionlink>
10356         </description>
10357       </capabilityfield>
10358       <capabilityfield id="can_set_native_method_prefix" since="1.1">
10359         <description>
10360           Can set prefix to be applied when native method cannot be resolved -
10361           <functionlink id="SetNativeMethodPrefix"/> and
10362           <functionlink id="SetNativeMethodPrefixes"/>
10363         </description>
10364       </capabilityfield>
10365       <capabilityfield id="can_retransform_classes" since="1.1">
10366         <description>
10367           Can retransform classes with <functionlink id="RetransformClasses"/>.
10368           In addition to the restrictions imposed by the specific
10369           implementation on this capability (see the
10370           <internallink id="capability">Capability</internallink> section),
10371           this capability must be set before the
10372           <eventlink id="ClassFileLoadHook"/> event is enabled for the
10373           first time in this environment.
10374           An environment that possesses this capability at the time that
10375           <code>ClassFileLoadHook</code> is enabled for the first time is
10376           said to be <i>retransformation capable</i>.
10377           An environment that does not possess this capability at the time that
10378           <code>ClassFileLoadHook</code> is enabled for the first time is
10379           said to be <i>retransformation incapable</i>.
10380         </description>
10381       </capabilityfield>
10382       <capabilityfield id="can_retransform_any_class" since="1.1">
10383         <description>
10384           <functionlink id="RetransformClasses"/> can be called on any modifiable class.
10385           See <functionlink id="IsModifiableClass"/>.
10386           (<fieldlink id="can_retransform_classes" struct="jvmtiCapabilities"/>
10387           must also be set)
10388         </description>
10389       </capabilityfield>
10390       <capabilityfield id="can_generate_resource_exhaustion_heap_events" since="1.1">
10391         <description>
10392           Can generate events when the VM is unable to allocate memory from
10393           the <tm>Java</tm> platform heap.
10394           See <eventlink id="ResourceExhausted"/>.
10395         </description>
10396       </capabilityfield>
10397       <capabilityfield id="can_generate_resource_exhaustion_threads_events" since="1.1">
10398         <description>
10399           Can generate events when the VM is unable to create a thread.
10400           See <eventlink id="ResourceExhausted"/>.
10401         </description>
10402       </capabilityfield>
10403       <capabilityfield id="can_generate_early_vmstart" since="9">
10404         <description>
10405           Can generate the <code>VMStart</code> event early.
10406           See <eventlink id="VMStart"/>.
10407         </description>
10408       </capabilityfield>
10409       <capabilityfield id="can_generate_early_class_hook_events" since="9">
10410         <description>
10411           Can generate the <eventlink id="ClassFileLoadHook"/> events
10412           in the primordial phase. If this capability and
10413           <internallink id="jvmtiCapabilities.can_generate_all_class_hook_events">
10414           <code>can_generate_all_class_hook_events</code></internallink>
10415           are enabled then the <eventlink id="ClassFileLoadHook"/> events
10416           can be posted for classes loaded in the primordial phase.
10417           See <eventlink id="ClassFileLoadHook"/>.
10418         </description>
10419       </capabilityfield>
10420       <capabilityfield id="can_generate_sampled_object_alloc_events" since="11">
10421         <description>
10422           Can generate sampled allocation events.
10423           If this capability is enabled then the heap sampling method
10424           <functionlink id="SetHeapSamplingInterval"></functionlink> can be
10425           called and <eventlink id="SampledObjectAlloc"></eventlink> events can be generated.
10426         </description>
10427       </capabilityfield>
10428     </capabilitiestypedef>
10429 
10430     <function id="GetPotentialCapabilities" jkernel="yes" phase="onload" num="140">
10431       <synopsis>Get Potential Capabilities</synopsis>
10432       <description>
10433         Returns via <paramlink id="capabilities_ptr"></paramlink> the <jvmti/>
10434         features that can potentially be possessed by this environment
10435         at this time.
10436         The returned capabilities differ from the complete set of capabilities
10437         implemented by the VM in two cases: another environment possesses
10438         capabilities that can only be possessed by one environment, or the
10439         current <functionlink id="GetPhase">phase</functionlink> is live,
10440         and certain capabilities can only be added during the <code>OnLoad</code> phase.
10441         The <functionlink id="AddCapabilities"></functionlink> function
10442         may be used to set any or all or these capabilities.
10443         Currently possessed capabilities are included.
10444         <p/>
10445         Typically this function is used in the <code>OnLoad</code> function.
10446         Some virtual machines may allow a limited set of capabilities to be
10447         added in the live phase.
10448         In this case, the set of potentially available capabilities
10449         will likely differ from the <code>OnLoad</code> phase set.
10450         <p/>
10451         See the
10452         <internallink id="capabilityExamples">Capability Examples</internallink>.
10453       </description>
10454       <origin>new</origin>
10455       <capabilities>
10456       </capabilities>
10457       <parameters>
10458         <param id="capabilities_ptr">
10459           <outptr><struct>jvmtiCapabilities</struct></outptr>
10460           <description>
10461             On return, points to the <jvmti/> capabilities that may be added.
10462           </description>
10463         </param>
10464       </parameters>
10465       <errors>
10466       </errors>
10467     </function>
10468 
10469     <elide>
10470     <function id="EstimateCostOfCapabilities" phase="onload" num="141">
10471       <synopsis>Estimate Cost Of Capabilities</synopsis>
10472       <description>
10473         <issue>There is strong opposition to this function.  The concern is
10474           that it would be difficult or impossible to provide meaningful
10475           numbers, as the amount of impact is conditional on many factors
10476           that a single number could not represent.  There is doubt that
10477           conditional implementations would be used or are even a good idea.
10478           The thought is that release documentation for the implementation
10479           would be the best means of exposing this information.
10480           Unless new arguments are presented, I intend to remove this
10481           function in the next revision.
10482         </issue>
10483         <p/>
10484         Return via the <paramlink id="time_impact_ptr"></paramlink> and
10485         <paramlink id="space_impact_ptr"></paramlink> an estimate of the impact
10486         of adding the capabilities pointed to by
10487         <paramlink id="capabilities_ptr"></paramlink>.
10488         The returned estimates are in percentage of additional overhead, thus
10489         a time impact of 100 mean the application might run
10490         at half the speed.
10491         The estimates are very rough approximations and are not guaranteed.
10492         Note also, that the estimates are of the impact of having the
10493         capability available--when and if it is used the impact may be
10494         much greater.
10495         Estimates can be for a single capability or for a set of
10496         capabilities.  Note that the costs are not necessarily additive,
10497         adding support for one capability might make another available
10498         for free or conversely having two capabilities at once may
10499         have multiplicative impact.
10500         Estimates are relative to the current set of capabilities -
10501         that is, how much more impact given the currently possessed capabilities.
10502         <p/>
10503         Typically this function is used in the OnLoad function,
10504         some virtual machines may allow a limited set of capabilities to be
10505         added in the live phase.
10506         In this case, the set of potentially available capabilities
10507         will likely differ from the OnLoad phase set.
10508         <p/>
10509         See the
10510         <internallink id="capabilityExamples">Capability Examples</internallink>.
10511       </description>
10512       <origin>new</origin>
10513       <capabilities>
10514       </capabilities>
10515       <parameters>
10516         <param id="capabilities_ptr">
10517           <inptr><struct>jvmtiCapabilities</struct></inptr>
10518           <description>
10519             points to the <jvmti/> capabilities to evaluate.
10520           </description>
10521         </param>
10522         <param id="time_impact_ptr">
10523           <outptr><jint/></outptr>
10524           <description>
10525             On return, points to the estimated percentage increase in
10526             run time if this capability was added.
10527           </description>
10528         </param>
10529         <param id="space_impact_ptr">
10530           <outptr><jint/></outptr>
10531           <description>
10532             On return, points to the estimated percentage increase in
10533             memory space used if this capability was added.
10534           </description>
10535         </param>
10536       </parameters>
10537       <errors>
10538         <error id="JVMTI_ERROR_NOT_AVAILABLE">
10539           The desired capabilities are not even potentially available.
10540         </error>
10541       </errors>
10542     </function>
10543     </elide>
10544 
10545     <function id="AddCapabilities" jkernel="yes" phase="onload" num="142">
10546       <synopsis>Add Capabilities</synopsis>
10547       <description>
10548         Set new capabilities by adding the capabilities
10549         whose values are set to one (<code>1</code>) in
10550         <code>*</code><paramlink id="capabilities_ptr"></paramlink>.
10551         All previous capabilities are retained.
10552         Typically this function is used in the <code>OnLoad</code> function.
10553         Some virtual machines may allow a limited set of capabilities to be
10554         added in the live phase.
10555         <p/>
10556         See the
10557         <internallink id="capabilityExamples">Capability Examples</internallink>.
10558       </description>
10559       <origin>new</origin>
10560       <capabilities>
10561       </capabilities>
10562       <parameters>
10563         <param id="capabilities_ptr">
10564           <inptr><struct>jvmtiCapabilities</struct></inptr>
10565           <description>
10566             Points to the <jvmti/> capabilities to add.
10567           </description>
10568         </param>
10569       </parameters>
10570       <errors>
10571         <error id="JVMTI_ERROR_NOT_AVAILABLE">
10572           The desired capabilities are not even potentially available.
10573         </error>
10574       </errors>
10575     </function>
10576 
10577 
10578     <function id="RelinquishCapabilities" phase="onload" num="143">
10579       <synopsis>Relinquish Capabilities</synopsis>
10580       <description>
10581         Relinquish the capabilities
10582         whose values are set to one (<code>1</code>) in
10583         <code>*</code><paramlink id="capabilities_ptr"></paramlink>.
10584         Some implementations may allow only one environment to have a capability
10585         (see the <internallink id="capability">capability introduction</internallink>).
10586         This function releases capabilities
10587         so that they may be used by other agents.
10588         All other capabilities are retained.
10589         The capability will no longer be present in <functionlink id="GetCapabilities"></functionlink>.
10590         Attempting to relinquish a capability that the agent does not possess is not an error.
10591           <issue>
10592             It is possible for the agent to be actively using capabilities
10593             which are being relinquished.  For example, a thread is currently
10594             suspended and can_suspend is being relinquished or an event is currently
10595             enabled and can_generate_whatever is being relinquished.
10596             There are three possible ways we could spec this:
10597             <ul>
10598               <li>relinquish automatically releases them</li>
10599               <li>relinquish checks and returns some error code if held</li>
10600               <li>it is the agent's responsibility and it is not checked</li>
10601             </ul>
10602             One of these should be chosen.
10603           </issue>
10604       </description>
10605       <origin>new</origin>
10606       <capabilities>
10607       </capabilities>
10608       <parameters>
10609         <param id="capabilities_ptr">
10610           <inptr><struct>jvmtiCapabilities</struct></inptr>
10611           <description>
10612             Points to the <jvmti/> capabilities to relinquish.
10613           </description>
10614         </param>
10615       </parameters>
10616       <errors>
10617       </errors>
10618     </function>
10619 
10620 
10621 
10622     <function id="GetCapabilities" jkernel="yes" phase="any" num="89">
10623       <synopsis>Get Capabilities</synopsis>
10624         <description>
10625           Returns via <paramlink id="capabilities_ptr"></paramlink> the optional <jvmti/>
10626           features which this environment currently possesses.
10627           Each possessed capability is indicated by a one (<code>1</code>) in the
10628           corresponding field of the <internallink id="jvmtiCapabilities">capabilities
10629           structure</internallink>.
10630           An environment does not possess a capability unless it has been successfully added with
10631           <functionlink id="AddCapabilities"/>.
10632           An environment only loses possession of a capability if it has been relinquished with
10633           <functionlink id="RelinquishCapabilities"/>. Thus, this function returns the net result
10634           of the <code>AddCapabilities</code> and <code>RelinquishCapabilities</code> calls which
10635           have been made.
10636           <p/>
10637           See the
10638           <internallink id="capabilityExamples">Capability Examples</internallink>.
10639         </description>
10640       <origin>jvmdiClone</origin>
10641       <capabilities>
10642       </capabilities>
10643       <parameters>
10644         <param id="capabilities_ptr">
10645           <outptr><struct>jvmtiCapabilities</struct></outptr>
10646           <description>
10647             On return, points to the <jvmti/> capabilities.
10648           </description>
10649         </param>
10650       </parameters>
10651       <errors>
10652       </errors>
10653     </function>
10654 
10655   </category>
10656 
10657 
10658   <category id="timers" label="Timers">
10659 
10660       <intro>
10661         These functions provide timing information.
10662         The resolution at which the time is updated is not specified.
10663         They provides nanosecond precision, but not necessarily nanosecond accuracy.
10664         Details about the timers, such as their maximum values, can be accessed with
10665         the timer information functions.
10666       </intro>
10667 
10668       <typedef id="jvmtiTimerInfo" label="Timer Info">
10669         <description>
10670           The information function for each timer returns this data structure.
10671         </description>
10672         <field id="max_value">
10673           <jlong/>
10674             <description>
10675               The maximum value the timer can reach.
10676               After this value is reached the timer wraps back to zero.
10677               This is an unsigned value.  If tested or printed as a jlong (signed value)
10678               it may appear to be a negative number.
10679             </description>
10680         </field>
10681         <field id="may_skip_forward">
10682           <jboolean/>
10683           <description>
10684             If true, the timer can be externally adjusted and as a result skip forward.
10685             If false, the timer value will never increase faster than real time.
10686           </description>
10687         </field>
10688         <field id="may_skip_backward">
10689           <jboolean/>
10690           <description>
10691             If true, the timer can be externally adjusted and as a result skip backward.
10692             If false, the timer value will be monotonically increasing.
10693           </description>
10694         </field>
10695         <field id="kind">
10696           <enum>jvmtiTimerKind</enum>
10697           <description>
10698             The kind of timer.
10699             On a platform that does not distinguish between user and system time, <datalink
10700                  id="JVMTI_TIMER_TOTAL_CPU"><code>JVMTI_TIMER_TOTAL_CPU</code></datalink>
10701             is returned.
10702           </description>
10703         </field>
10704         <field id="reserved1">
10705           <jlong/>
10706             <description>
10707               Reserved for future use.
10708             </description>
10709         </field>
10710         <field id="reserved2">
10711           <jlong/>
10712             <description>
10713               Reserved for future use.
10714             </description>
10715         </field>
10716       </typedef>
10717 
10718       <intro>
10719         Where the timer kind is --
10720 
10721         <constants id="jvmtiTimerKind" label="Timer Kinds" kind="enum">
10722           <constant id="JVMTI_TIMER_USER_CPU" num="30">
10723             CPU time that a thread is in user mode.
10724           </constant>
10725           <constant id="JVMTI_TIMER_TOTAL_CPU" num="31">
10726             CPU time that a thread is in user or system mode.
10727           </constant>
10728           <constant id="JVMTI_TIMER_ELAPSED" num="32">
10729             Elapsed time.
10730           </constant>
10731         </constants>
10732       </intro>
10733 
10734     <function id="GetCurrentThreadCpuTimerInfo" callbacksafe="safe"  impl="innative notrace" phase="start" num="134">
10735       <synopsis>Get Current Thread CPU Timer Information</synopsis>
10736       <description>
10737         Get information about the
10738         <functionlink id="GetCurrentThreadCpuTime"/> timer.
10739         The fields of the <datalink id="jvmtiTimerInfo"/> structure
10740         are filled in with details about the timer.
10741         This information is specific to the platform and the implementation of
10742         <functionlink id="GetCurrentThreadCpuTime"/> and thus
10743         does not vary by thread nor does it vary
10744         during a particular invocation of the VM.
10745         <p/>
10746         Note that the implementations of <functionlink id="GetCurrentThreadCpuTime"/>
10747         and <functionlink id="GetThreadCpuTime"/> may differ, and thus the values
10748         returned by <code>GetCurrentThreadCpuTimerInfo</code>
10749         and <functionlink id="GetThreadCpuTimerInfo"/>
10750         may differ -- see <functionlink id="GetCurrentThreadCpuTime"/> for more information.
10751       </description>
10752       <origin>new</origin>
10753       <capabilities>
10754         <required id="can_get_current_thread_cpu_time">
10755             Can get current thread CPU time.
10756         </required>
10757       </capabilities>
10758       <parameters>
10759         <param id="info_ptr">
10760           <outptr><struct>jvmtiTimerInfo</struct></outptr>
10761           <description>
10762             On return, filled with information describing the time
10763             returned by <functionlink id="GetCurrentThreadCpuTime"/>.
10764           </description>
10765         </param>
10766       </parameters>
10767       <errors>
10768       </errors>
10769     </function>
10770 
10771     <function id="GetCurrentThreadCpuTime" callbacksafe="safe" impl="innative notrace" phase="start" num="135">
10772       <synopsis>Get Current Thread CPU Time</synopsis>
10773       <description>
10774             Return the CPU time utilized by the current thread.
10775             <p/>
10776             Note that the <functionlink id="GetThreadCpuTime"/>
10777             function provides CPU time for any thread, including
10778             the current thread. <code>GetCurrentThreadCpuTime</code>
10779             exists to support platforms which cannot
10780             supply CPU time for threads other than the current
10781             thread or which have more accurate information for
10782             the current thread (see
10783             <functionlink id="GetCurrentThreadCpuTimerInfo"/> vs
10784             <functionlink id="GetThreadCpuTimerInfo"/>).
10785             On many platforms this call will be equivalent to:
10786 <example>
10787   GetThreadCpuTime(env, NULL, nanos_ptr)
10788 </example>
10789       </description>
10790       <origin>new</origin>
10791       <capabilities>
10792         <required id="can_get_current_thread_cpu_time">
10793             Can get current thread CPU time.
10794             <p/>
10795             If this capability is enabled after threads have started,
10796             the implementation may choose any time up
10797             to and including the time that the capability is enabled
10798             as the point where CPU time collection starts.
10799             <p/>
10800             This capability must be potentially available on any
10801             platform where
10802             <internallink id="jvmtiCapabilities.can_get_thread_cpu_time"><code>can_get_thread_cpu_time</code></internallink>
10803             is potentially available.
10804         </required>
10805       </capabilities>
10806       <parameters>
10807         <param id="nanos_ptr">
10808           <outptr><jlong/></outptr>
10809           <description>
10810             On return, points to the CPU time used by this thread
10811             in nanoseconds.
10812             This is an unsigned value.  If tested or printed as a jlong (signed value)
10813             it may appear to be a negative number.
10814           </description>
10815         </param>
10816       </parameters>
10817       <errors>
10818       </errors>
10819     </function>
10820 
10821     <function id="GetThreadCpuTimerInfo" num="136">
10822       <synopsis>Get Thread CPU Timer Information</synopsis>
10823       <description>
10824         Get information about the
10825         <functionlink id="GetThreadCpuTime"/> timer.
10826         The fields of the <datalink id="jvmtiTimerInfo"/> structure
10827         are filled in with details about the timer.
10828         This information is specific to the platform and the implementation of
10829         <functionlink id="GetThreadCpuTime"/> and thus
10830         does not vary by thread nor does it vary
10831         during a particular invocation of the VM.
10832         <p/>
10833         Note that the implementations of <functionlink id="GetCurrentThreadCpuTime"/>
10834         and <functionlink id="GetThreadCpuTime"/> may differ, and thus the values
10835         returned by <functionlink id="GetCurrentThreadCpuTimerInfo"/>
10836         and <code>GetThreadCpuTimerInfo</code>
10837         may differ -- see <functionlink id="GetCurrentThreadCpuTime"/> for more information.
10838       </description>
10839       <origin>new</origin>
10840       <capabilities>
10841         <required id="can_get_thread_cpu_time">
10842             Can get thread CPU time.
10843         </required>
10844       </capabilities>
10845       <parameters>
10846         <param id="info_ptr">
10847           <outptr><struct>jvmtiTimerInfo</struct></outptr>
10848           <description>
10849             On return, filled with information describing the time
10850             returned by <functionlink id="GetThreadCpuTime"/>.
10851           </description>
10852         </param>
10853       </parameters>
10854       <errors>
10855       </errors>
10856     </function>
10857 
10858     <function id="GetThreadCpuTime" num="137">
10859       <synopsis>Get Thread CPU Time</synopsis>
10860       <description>
10861           Return the CPU time utilized by the specified thread.
10862           <p/>
10863           Get information about this timer with
10864           <functionlink id="GetThreadCpuTimerInfo"/>.
10865       </description>
10866       <origin>new</origin>
10867       <capabilities>
10868         <required id="can_get_thread_cpu_time">
10869             Can get thread CPU time.
10870             <p/>
10871             If this capability is enabled after threads have started,
10872             the implementation may choose any time up
10873             to and including the time that the capability is enabled
10874             as the point where CPU time collection starts.
10875         </required>
10876       </capabilities>
10877       <parameters>
10878         <param id="thread">
10879           <jthread null="current"/>
10880             <description>
10881               The thread to query.
10882             </description>
10883         </param>
10884         <param id="nanos_ptr">
10885           <outptr><jlong/></outptr>
10886           <description>
10887             On return, points to the CPU time used by the specified thread
10888             in nanoseconds.
10889             This is an unsigned value.  If tested or printed as a jlong (signed value)
10890             it may appear to be a negative number.
10891           </description>
10892         </param>
10893       </parameters>
10894       <errors>
10895       </errors>
10896     </function>
10897 
10898     <function id="GetTimerInfo" phase="any" callbacksafe="safe" num="138">
10899       <synopsis>Get Timer Information</synopsis>
10900       <description>
10901         Get information about the
10902         <functionlink id="GetTime"/> timer.
10903         The fields of the <datalink id="jvmtiTimerInfo"/> structure
10904         are filled in with details about the timer.
10905         This information will not change during a particular invocation of the VM.
10906       </description>
10907       <origin>new</origin>
10908       <capabilities>
10909       </capabilities>
10910       <parameters>
10911         <param id="info_ptr">
10912           <outptr><struct>jvmtiTimerInfo</struct></outptr>
10913           <description>
10914             On return, filled with information describing the time
10915             returned by <functionlink id="GetTime"/>.
10916           </description>
10917         </param>
10918       </parameters>
10919       <errors>
10920       </errors>
10921     </function>
10922 
10923     <function id="GetTime" phase="any" callbacksafe="safe" num="139">
10924       <synopsis>Get Time</synopsis>
10925       <description>
10926           Return the current value of the system timer, in nanoseconds.
10927           <p/>
10928           The value returned represents nanoseconds since some fixed but
10929           arbitrary time (perhaps in the future, so values may be
10930           negative).  This function provides nanosecond precision, but not
10931           necessarily nanosecond accuracy. No guarantees are made about
10932           how frequently values change.
10933           <p/>
10934           Get information about this timer with
10935           <functionlink id="GetTimerInfo"/>.
10936       </description>
10937       <origin>new</origin>
10938       <capabilities>
10939       </capabilities>
10940       <parameters>
10941         <param id="nanos_ptr">
10942           <outptr><jlong/></outptr>
10943           <description>
10944             On return, points to the time in nanoseconds.
10945             This is an unsigned value.  If tested or printed as a jlong (signed value)
10946             it may appear to be a negative number.
10947           </description>
10948         </param>
10949       </parameters>
10950       <errors>
10951       </errors>
10952     </function>
10953 
10954     <function id="GetAvailableProcessors" phase="any" num="144">
10955       <synopsis>Get Available Processors</synopsis>
10956       <description>
10957           Returns the number of processors available to the Java virtual machine.
10958           <p/>
10959           This value may change during a particular invocation of the virtual machine.
10960           Applications that are sensitive to the number of available processors should
10961           therefore occasionally poll this property.
10962       </description>
10963       <origin>new</origin>
10964       <capabilities>
10965       </capabilities>
10966       <parameters>
10967         <param id="processor_count_ptr">
10968           <outptr><jint/></outptr>
10969           <description>
10970             On return, points to the maximum number of processors available to the
10971             virtual machine; never smaller than one.
10972           </description>
10973         </param>
10974       </parameters>
10975       <errors>
10976       </errors>
10977     </function>
10978 
10979   </category>
10980 
10981 
10982   <category id="classLoaderSearch" label="Class Loader Search">
10983 
10984     <intro>
10985       These functions allow the agent to add to the locations that a class loader searches for a class.
10986       This is useful for installing instrumentation under the correct class loader.
10987     </intro>
10988 
10989     <function id="AddToBootstrapClassLoaderSearch" jkernel="yes" phase="onload" num="149">
10990       <synopsis>Add To Bootstrap Class Loader Search</synopsis>
10991       <description>
10992           This function can be used to cause instrumentation classes to be defined by the
10993           bootstrap class loader. See <vmspec chapter="5.3.1"/>.
10994           After the bootstrap
10995           class loader unsuccessfully searches for a class, the specified platform-dependent
10996           search path <paramlink id="segment"/> will be searched as well. Only one segment may be specified in
10997           the <paramlink id="segment"/>. This function may be called multiple times to add multiple segments,
10998           the segments will be searched in the order that this function was called.
10999           <p/>
11000           In the <code>OnLoad</code> phase the function may be used to specify any platform-dependent
11001           search path segment to be searched after the bootstrap class loader unsuccessfully searches
11002           for a class. The segment is typically a directory or JAR file.
11003           <p/>
11004           In the live phase the <paramlink id="segment"/> may be used to specify any platform-dependent
11005           path to a <externallink id="jar/jar.html">
11006           JAR file</externallink>. The agent should take care that the JAR file does not
11007           contain any classes or resources other than those to be defined by the bootstrap
11008           class loader for the purposes of instrumentation.
11009           <p/>
11010           <vmspec/> specifies that a subsequent attempt to resolve a symbolic
11011           reference that the Java virtual machine has previously unsuccessfully attempted
11012           to resolve always fails with the same error that was thrown as a result of the
11013           initial resolution attempt. Consequently, if the JAR file contains an entry
11014           that corresponds to a class for which the Java virtual machine has
11015           unsuccessfully attempted to resolve a reference, then subsequent attempts to
11016           resolve that reference will fail with the same error as the initial attempt.
11017       </description>
11018       <origin>new</origin>
11019       <capabilities>
11020       </capabilities>
11021       <parameters>
11022         <param id="segment">
11023           <inbuf><char/></inbuf>
11024           <description>
11025             The platform-dependent search path segment, encoded as a
11026             <internallink id="mUTF">modified UTF-8</internallink> string.
11027           </description>
11028         </param>
11029       </parameters>
11030       <errors>
11031         <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
11032           <paramlink id="segment"/> is an invalid path. In the live phase, anything other than an
11033            existing JAR file is an invalid path.
11034         </error>
11035       </errors>
11036     </function>
11037 
11038     <function id="AddToSystemClassLoaderSearch" jkernel="yes" phase="onload" num="151" since="1.1">
11039       <synopsis>Add To System Class Loader Search</synopsis>
11040       <description>
11041           This function can be used to cause instrumentation classes to be
11042           defined by the system class loader. See <vmspec chapter="5.3.2"/>.
11043           After the class loader unsuccessfully searches for a class, the specified platform-dependent search
11044           path <paramlink id="segment"/> will be searched as well. Only one segment may be specified in the
11045           <paramlink id="segment"/>. This function may be called multiple times to add multiple segments, the
11046           segments will be searched in the order that this function was called.
11047           <p/>
11048           In the <code>OnLoad</code> phase the function may be used to specify any platform-dependent
11049           search path segment to be searched after the system class loader unsuccessfully searches
11050           for a class. The segment is typically a directory or JAR file.
11051           <p/>
11052           In the live phase the <paramlink id="segment"/> is a platform-dependent path to a
11053           <externallink id="jar/jar.html">JAR file</externallink> to be
11054           searched after the system class loader unsuccessfully searches for a class. The agent should
11055           take care that the JAR file does not contain any classes or resources other than those to be
11056           defined by the system class loader for the purposes of instrumentation.
11057           <p/>
11058           In the live phase the system class loader supports adding a JAR file to be searched if
11059           the system class loader implements a method name <code>appendToClassPathForInstrumentation</code>
11060           which takes a single parameter of type <code>java.lang.String</code>. The method is not required
11061           to have <code>public</code> access.
11062           <p/>
11063           <vmspec/> specifies that a subsequent attempt to resolve a symbolic
11064           reference that the Java virtual machine has previously unsuccessfully attempted
11065           to resolve always fails with the same error that was thrown as a result of the
11066           initial resolution attempt. Consequently, if the JAR file contains an entry
11067           that corresponds to a class for which the Java virtual machine has
11068           unsuccessfully attempted to resolve a reference, then subsequent attempts to
11069           resolve that reference will fail with the same error as the initial attempt.
11070       </description>
11071       <origin>new</origin>
11072       <capabilities>
11073       </capabilities>
11074       <parameters>
11075         <param id="segment">
11076           <inbuf><char/></inbuf>
11077           <description>
11078             The platform-dependent search path segment, encoded as a
11079             <internallink id="mUTF">modified UTF-8</internallink> string.
11080           </description>
11081         </param>
11082       </parameters>
11083       <errors>
11084         <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
11085           <paramlink id="segment"/> is an invalid path. In the live phase, anything other than an
11086            existing JAR file is an invalid path.
11087         </error>
11088         <error id="JVMTI_ERROR_CLASS_LOADER_UNSUPPORTED">
11089           Operation not supported by the system class loader.
11090         </error>
11091       </errors>
11092     </function>
11093 
11094   </category>
11095 
11096 
11097   <category id="props" label="System Properties">
11098 
11099     <intro>
11100       These functions get and set system properties.
11101     </intro>
11102 
11103     <function id="GetSystemProperties" phase="onload" num="130">
11104       <synopsis>Get System Properties</synopsis>
11105       <description>
11106         The list of VM system property keys which may be used with
11107         <functionlink id="GetSystemProperty"/> is returned.
11108         It is strongly recommended that virtual machines provide the
11109         following property keys:
11110         <ul>
11111           <li><code>java.vm.vendor</code></li>
11112           <li><code>java.vm.version</code></li>
11113           <li><code>java.vm.name</code></li>
11114           <li><code>java.vm.info</code></li>
11115           <li><code>java.library.path</code></li>
11116           <li><code>java.class.path</code></li>
11117         </ul>
11118         Provides access to system properties defined by and used
11119         by the VM.
11120         Properties set on the command-line are included.
11121         This allows getting and setting of these properties
11122         before the VM even begins executing bytecodes.
11123         Since this is a VM view of system properties, the set of available
11124         properties will usually be different than that
11125         in <code>java.lang.System.getProperties</code>.
11126         JNI method invocation may be used to access
11127         <code>java.lang.System.getProperties</code>.
11128         <p/>
11129         The set of properties may grow during execution.
11130       </description>
11131       <origin>new</origin>
11132       <capabilities>
11133       </capabilities>
11134       <parameters>
11135         <param id="count_ptr">
11136           <outptr><jint/></outptr>
11137           <description>
11138             On return, points to the number of property keys returned.
11139           </description>
11140         </param>
11141         <param id="property_ptr">
11142           <allocallocbuf outcount="count_ptr"><char/></allocallocbuf>
11143           <description>
11144             On return, points to an array of property keys, encoded as
11145             <internallink id="mUTF">modified UTF-8</internallink> strings.
11146           </description>
11147         </param>
11148       </parameters>
11149       <errors>
11150       </errors>
11151     </function>
11152 
11153     <function id="GetSystemProperty" phase="onload" num="131">
11154       <synopsis>Get System Property</synopsis>
11155       <description>
11156         Return a VM system property value given the property key.
11157         <p/>
11158         The function <functionlink id="GetSystemProperties"/>
11159         returns the set of property keys which may be used.
11160         The properties which can be retrieved may grow during
11161         execution.
11162         <p/>
11163         Since this is a VM view of system properties, the values
11164         of properties may differ from that returned by
11165         <code>java.lang.System.getProperty(String)</code>.
11166         A typical VM might copy the values of the VM system
11167         properties into the <code>Properties</code> held by
11168         <code>java.lang.System</code> during the initialization
11169         of that class. Thereafter any changes to the VM system
11170         properties (with <functionlink id="SetSystemProperty"/>)
11171         or the <code>java.lang.System</code> system properties
11172         (with <code>java.lang.System.setProperty(String,String)</code>)
11173         would cause the values to diverge.
11174         JNI method invocation may be used to access
11175         <code>java.lang.System.getProperty(String)</code>.
11176       </description>
11177       <origin>new</origin>
11178       <capabilities>
11179       </capabilities>
11180       <parameters>
11181         <param id="property">
11182           <inbuf><char/></inbuf>
11183           <description>
11184             The key of the property to retrieve, encoded as a
11185             <internallink id="mUTF">modified UTF-8</internallink> string.
11186           </description>
11187         </param>
11188         <param id="value_ptr">
11189           <allocbuf><char/></allocbuf>
11190           <description>
11191             On return, points to the property value, encoded as a
11192             <internallink id="mUTF">modified UTF-8</internallink> string.
11193           </description>
11194         </param>
11195       </parameters>
11196       <errors>
11197         <error id="JVMTI_ERROR_NOT_AVAILABLE">
11198           This property is not available.
11199           Use <functionlink id="GetSystemProperties"/> to find available properties.
11200         </error>
11201       </errors>
11202     </function>
11203 
11204     <function id="SetSystemProperty" phase="onloadOnly" num="132">
11205       <synopsis>Set System Property</synopsis>
11206       <description>
11207         Set a VM system property value.
11208         <p/>
11209         The function <functionlink id="GetSystemProperties"/>
11210         returns the set of property keys, some of these may be settable.
11211         See <functionlink id="GetSystemProperty"/>.
11212       </description>
11213       <origin>new</origin>
11214       <capabilities>
11215       </capabilities>
11216       <parameters>
11217         <param id="property">
11218           <inbuf><char/></inbuf>
11219           <description>
11220             The key of the property, encoded as a
11221             <internallink id="mUTF">modified UTF-8</internallink> string.
11222           </description>
11223         </param>
11224         <param id="value_ptr">
11225           <inbuf>
11226             <char/>
11227             <nullok>
11228               do not set the value, but return <errorlink id="JVMTI_ERROR_NOT_AVAILABLE"/>
11229               if the property is not writeable
11230             </nullok>
11231           </inbuf>
11232           <description>
11233             The property value to set, encoded as a
11234             <internallink id="mUTF">modified UTF-8</internallink> string.
11235           </description>
11236         </param>
11237       </parameters>
11238       <errors>
11239         <error id="JVMTI_ERROR_NOT_AVAILABLE">
11240           This property is not available or is not writeable.
11241         </error>
11242       </errors>
11243     </function>
11244 
11245   </category>
11246 
11247   <category id="general" label="General">
11248 
11249     <intro>
11250     </intro>
11251 
11252     <function id="GetPhase" jkernel="yes" phase="any" num="133">
11253       <synopsis>Get Phase</synopsis>
11254       <description>
11255           Return the current phase of VM execution.
11256           The phases proceed in sequence:
11257           <constants id="jvmtiPhase" label="Phases of execution" kind="enum">
11258             <constant id="JVMTI_PHASE_ONLOAD" num="1">
11259               <code>OnLoad</code> phase: while in the
11260               <internallink id="onload"><code>Agent_OnLoad</code></internallink>
11261               or, for statically linked agents, the <internallink id="onload">
11262               <code>Agent_OnLoad_&lt;agent-lib-name&gt;
11263               </code></internallink> function.
11264             </constant>
11265             <constant id="JVMTI_PHASE_PRIMORDIAL" num="2">
11266               Primordial phase: between return from <code>Agent_OnLoad</code>
11267               or <code>Agent_OnLoad_&lt;agent-lib-name&gt;</code> and the
11268               <code>VMStart</code> event.
11269             </constant>
11270             <constant id="JVMTI_PHASE_START" num="6">
11271               Start phase: when the <eventlink id="VMStart"><code>VMStart</code></eventlink> event
11272               is sent and until the <code>VMInit</code> event is sent.
11273             </constant>
11274             <constant id="JVMTI_PHASE_LIVE" num="4">
11275               Live phase: when the <eventlink id="VMInit"><code>VMInit</code></eventlink> event is sent
11276               and until the <eventlink id="VMDeath"></eventlink> event returns.
11277             </constant>
11278             <constant id="JVMTI_PHASE_DEAD" num="8">
11279               Dead phase: after the <eventlink id="VMDeath"></eventlink> event returns or after
11280               start-up failure.
11281             </constant>
11282           </constants>
11283           In the case of start-up failure the VM will proceed directly to the dead
11284           phase skipping intermediate phases and neither a <code>VMInit</code> nor
11285           <code>VMDeath</code> event will be sent.
11286           <p/>
11287           Most <jvmti/> functions operate only in the live phase.
11288           The following functions operate in either the <code>OnLoad</code> or live phases:
11289           <functionphaselist phase="onload"/>
11290           The following functions operate in only the <code>OnLoad</code> phase:
11291           <functionphaselist phase="onloadOnly"/>
11292           The following functions operate in the start or live phases:
11293           <functionphaselist phase="start"/>
11294           The following functions operate in any phase:
11295           <functionphaselist phase="any"/>
11296           JNI functions (except the Invocation API) must only be used in the start or live phases.
11297           <p/>
11298           Most <jvmti/> events are sent only in the live phase.
11299           The following events operate in others phases:
11300           <eventphaselist phase="start"/>
11301           <eventphaselist phase="any"/>
11302       </description>
11303       <origin>new</origin>
11304       <capabilities>
11305       </capabilities>
11306       <parameters>
11307         <param id="phase_ptr">
11308           <outptr><enum>jvmtiPhase</enum></outptr>
11309           <description>
11310             On return, points to the phase.
11311           </description>
11312         </param>
11313       </parameters>
11314       <errors>
11315       </errors>
11316     </function>
11317 
11318     <function id="DisposeEnvironment" jkernel="yes" phase="any" num="127">
11319       <synopsis>Dispose Environment</synopsis>
11320       <description>
11321         Shutdown a <jvmti/> connection created with JNI <code>GetEnv</code>
11322         (see <internallink id="environments"><jvmti/> Environments</internallink>).
11323         Dispose of any resources held by the environment.
11324         <issue>
11325             What resources are reclaimed? What is undone?
11326             Breakpoints,watchpoints removed?
11327         </issue>
11328         Threads suspended by this environment are not resumed by this call,
11329         this must be done explicitly by the agent.
11330         Memory allocated by this environment via calls to <jvmti/> functions
11331         is not released, this can be done explicitly by the agent
11332         by calling <functionlink id="Deallocate"/>.
11333         Raw monitors created by this environment are not destroyed,
11334         this can be done explicitly by the agent
11335         by calling <functionlink id="DestroyRawMonitor"/>.
11336         The state of threads waiting on raw monitors created by this environment
11337         are not affected.
11338         <p/>
11339         Any <functionlink id="SetNativeMethodPrefix">native method
11340         prefixes</functionlink> for this environment will be unset;
11341         the agent must remove any prefixed native methods before
11342         dispose is called.
11343         <p/>
11344         Any <internallink id="capability">capabilities</internallink>
11345         held by this environment are relinquished.
11346         <p/>
11347         Events enabled by this environment will no longer be sent, however
11348         event handlers currently running will continue to run.  Caution must
11349         be exercised in the design of event handlers whose environment may
11350         be disposed and thus become invalid during their execution.
11351         <p/>
11352         This environment may not be used after this call.
11353         This call returns to the caller.
11354       </description>
11355       <origin>new</origin>
11356       <capabilities>
11357       </capabilities>
11358       <parameters>
11359       </parameters>
11360       <errors>
11361       </errors>
11362     </function>
11363 
11364     <function id="SetEnvironmentLocalStorage" jkernel="yes" phase="any" callbacksafe="safe" impl="innative notrace" num="148">
11365       <synopsis>Set Environment Local Storage</synopsis>
11366       <description>
11367         The VM stores a pointer value associated with each environment.
11368         This pointer value is called <i>environment-local storage</i>.
11369         This value is <code>NULL</code> unless set with this function.
11370         Agents can allocate memory in which they store environment specific
11371         information. By setting environment-local storage it can then be
11372         accessed with
11373         <functionlink id="GetEnvironmentLocalStorage"></functionlink>.
11374         <p/>
11375         Called by the agent to set the value of the <jvmti/>
11376         environment-local storage. <jvmti/> supplies to the agent a pointer-size
11377         environment-local storage that can be used to record per-environment
11378         information.
11379       </description>
11380       <origin>new</origin>
11381       <capabilities>
11382       </capabilities>
11383       <parameters>
11384         <param id="data">
11385           <inbuf>
11386             <void/>
11387             <nullok>value is set to <code>NULL</code></nullok>
11388           </inbuf>
11389           <description>
11390             The value to be entered into the environment-local storage.
11391           </description>
11392         </param>
11393       </parameters>
11394       <errors>
11395       </errors>
11396     </function>
11397 
11398     <function id="GetEnvironmentLocalStorage" jkernel="yes" phase="any" callbacksafe="safe" impl="innative notrace" num="147">
11399       <synopsis>Get Environment Local Storage</synopsis>
11400       <description>
11401         Called by the agent to get the value of the <jvmti/> environment-local
11402         storage.
11403       </description>
11404       <origin>new</origin>
11405       <capabilities>
11406       </capabilities>
11407       <parameters>
11408         <param id="data_ptr">
11409           <agentbuf><void/></agentbuf>
11410           <description>
11411             Pointer through which the value of the environment local
11412             storage is returned.
11413             If environment-local storage has not been set with
11414             <functionlink id="SetEnvironmentLocalStorage"></functionlink> returned
11415             pointer is <code>NULL</code>.
11416           </description>
11417         </param>
11418       </parameters>
11419       <errors>
11420       </errors>
11421     </function>
11422 
11423     <function id="GetVersionNumber" jkernel="yes" phase="any" num="88">
11424       <synopsis>Get Version Number</synopsis>
11425       <description>
11426         Return the <jvmti/> version via <code>version_ptr</code>.
11427         The return value is the version identifier.
11428         The version identifier includes major, minor and micro
11429         version as well as the interface type.
11430         <constants id="jvmtiVersionInterfaceTypes" label="Version Interface Types" kind="bits">
11431           <constant id="JVMTI_VERSION_INTERFACE_JNI" num="0x00000000">
11432             Value of <code>JVMTI_VERSION_MASK_INTERFACE_TYPE</code> for JNI.
11433           </constant>
11434           <constant id="JVMTI_VERSION_INTERFACE_JVMTI" num="0x30000000">
11435             Value of <code>JVMTI_VERSION_MASK_INTERFACE_TYPE</code> for <jvmti/>.
11436           </constant>
11437         </constants>
11438         <constants id="jvmtiVersionMasks" label="Version Masks" kind="bits">
11439           <constant id="JVMTI_VERSION_MASK_INTERFACE_TYPE" num="0x70000000">
11440             Mask to extract interface type.
11441             The value of the version returned by this function masked with
11442             <code>JVMTI_VERSION_MASK_INTERFACE_TYPE</code> is always
11443             <code>JVMTI_VERSION_INTERFACE_JVMTI</code>
11444             since this is a <jvmti/> function.
11445           </constant>
11446           <constant id="JVMTI_VERSION_MASK_MAJOR" num="0x0FFF0000">
11447             Mask to extract major version number.
11448           </constant>
11449           <constant id="JVMTI_VERSION_MASK_MINOR" num="0x0000FF00">
11450             Mask to extract minor version number.
11451           </constant>
11452           <constant id="JVMTI_VERSION_MASK_MICRO" num="0x000000FF">
11453             Mask to extract micro version number.
11454           </constant>
11455         </constants>
11456         <constants id="jvmtiVersionShifts" label="Version Shifts" kind="bits">
11457           <constant id="JVMTI_VERSION_SHIFT_MAJOR" num="16">
11458             Shift to extract major version number.
11459           </constant>
11460           <constant id="JVMTI_VERSION_SHIFT_MINOR" num="8">
11461             Shift to extract minor version number.
11462           </constant>
11463           <constant id="JVMTI_VERSION_SHIFT_MICRO" num="0">
11464             Shift to extract micro version number.
11465           </constant>
11466         </constants>
11467       </description>
11468       <origin>jvmdi</origin>
11469       <capabilities>
11470       </capabilities>
11471       <parameters>
11472         <param id="version_ptr">
11473           <outptr><jint/></outptr>
11474           <description>
11475             On return, points to the <jvmti/> version.
11476           </description>
11477         </param>
11478       </parameters>
11479       <errors>
11480       </errors>
11481     </function>
11482 
11483 
11484     <function id="GetErrorName" phase="any" num="128">
11485       <synopsis>Get Error Name</synopsis>
11486       <description>
11487         Return the symbolic name for an
11488           <internallink id="ErrorSection">error code</internallink>.
11489         <p/>
11490         For example
11491         <code>GetErrorName(env, JVMTI_ERROR_NONE, &amp;err_name)</code>
11492         would return in <code>err_name</code> the string
11493         <code>"JVMTI_ERROR_NONE"</code>.
11494       </description>
11495       <origin>new</origin>
11496       <capabilities>
11497       </capabilities>
11498       <parameters>
11499         <param id="error">
11500           <enum>jvmtiError</enum>
11501           <description>
11502             The error code.
11503           </description>
11504         </param>
11505         <param id="name_ptr">
11506           <allocbuf><char/></allocbuf>
11507           <description>
11508             On return, points to the error name.
11509             The name is encoded as a
11510             <internallink id="mUTF">modified UTF-8</internallink> string,
11511             but is restricted to the ASCII subset.
11512           </description>
11513         </param>
11514       </parameters>
11515       <errors>
11516       </errors>
11517     </function>
11518 
11519     <function id="SetVerboseFlag" phase="any" num="150">
11520       <synopsis>Set Verbose Flag</synopsis>
11521       <description>
11522         <constants id="jvmtiVerboseFlag" label="Verbose Flag Enumeration" kind="enum">
11523           <constant id="JVMTI_VERBOSE_OTHER" num="0">
11524             Verbose output other than the below.
11525           </constant>
11526           <constant id="JVMTI_VERBOSE_GC" num="1">
11527             Verbose garbage collector output, like that specified with <code>-verbose:gc</code>.
11528           </constant>
11529           <constant id="JVMTI_VERBOSE_CLASS" num="2">
11530             Verbose class loading output, like that specified with <code>-verbose:class</code>.
11531           </constant>
11532           <constant id="JVMTI_VERBOSE_JNI" num="4">
11533             Verbose JNI output, like that specified with <code>-verbose:jni</code>.
11534           </constant>
11535         </constants>
11536         Control verbose output.
11537         This is the output which typically is sent to <code>stderr</code>.
11538       </description>
11539       <origin>new</origin>
11540       <capabilities>
11541       </capabilities>
11542       <parameters>
11543         <param id="flag">
11544           <enum>jvmtiVerboseFlag</enum>
11545           <description>
11546             Which verbose flag to set.
11547           </description>
11548         </param>
11549         <param id="value">
11550           <jboolean/>
11551           <description>
11552             New value of the flag.
11553           </description>
11554         </param>
11555       </parameters>
11556       <errors>
11557       </errors>
11558     </function>
11559 
11560 
11561     <function id="GetJLocationFormat" phase="any" num="129">
11562       <synopsis>Get JLocation Format</synopsis>
11563       <description>
11564         Although the greatest functionality is achieved with location information
11565         referencing the virtual machine bytecode index, the definition of
11566         <code>jlocation</code> has intentionally been left unconstrained to allow VM
11567         implementations that do not have this information.
11568         <p/>
11569         This function describes the representation of <code>jlocation</code> used in this VM.
11570         If the returned format is <datalink id="JVMTI_JLOCATION_JVMBCI"></datalink>,
11571         <code>jlocation</code>s can
11572         be used as in indices into the array returned by
11573         <functionlink id="GetBytecodes"></functionlink>.
11574         <constants id="jvmtiJlocationFormat" label="JLocation Format Enumeration" kind="enum">
11575           <constant id="JVMTI_JLOCATION_JVMBCI" num="1">
11576             <code>jlocation</code> values represent virtual machine
11577             bytecode indices--that is, offsets into the
11578             virtual machine code for a method.
11579           </constant>
11580           <constant id="JVMTI_JLOCATION_MACHINEPC" num="2">
11581             <code>jlocation</code> values represent native machine
11582             program counter values.
11583           </constant>
11584           <constant id="JVMTI_JLOCATION_OTHER" num="0">
11585             <code>jlocation</code> values have some other representation.
11586           </constant>
11587         </constants>
11588       </description>
11589       <origin>new</origin>
11590       <capabilities>
11591       </capabilities>
11592       <parameters>
11593         <param id="format_ptr">
11594           <outptr><enum>jvmtiJlocationFormat</enum></outptr>
11595           <description>
11596             On return, points to the format identifier for <code>jlocation</code> values.
11597           </description>
11598         </param>
11599       </parameters>
11600       <errors>
11601       </errors>
11602     </function>
11603 
11604   </category>
11605 
11606   <category id="heap_monitoring" label="Heap Monitoring">
11607     <function id="SetHeapSamplingInterval" phase="onload" num="156" since="11">
11608       <synopsis>Set Heap Sampling Interval</synopsis>
11609       <description>
11610         Generate a <eventlink id="SampledObjectAlloc"/> event when objects are allocated.
11611         Each thread keeps a counter of bytes allocated. The event will only be generated
11612         when that counter exceeds an average of <paramlink id="sampling_interval"></paramlink>
11613         since the last sample.
11614         <p/>
11615         Setting <paramlink id="sampling_interval"></paramlink> to 0 will cause an event to be
11616         generated by each allocation supported by the system once the new interval is taken into account.
11617         <p/>
11618         Note that updating the new sampling interval might take various number of allocations
11619         to provoke internal data structure updates.  Therefore it is important to
11620         consider the sampling interval as an average. This includes the interval 0, where events
11621         might not be generated straight away for each allocation.
11622       </description>
11623       <origin>new</origin>
11624       <capabilities>
11625         <required id="can_generate_sampled_object_alloc_events"></required>
11626       </capabilities>
11627       <parameters>
11628         <param id="sampling_interval">
11629           <jint/>
11630           <description>
11631             The sampling interval in bytes. The sampler uses a statistical approach to
11632             generate an event, on average, once for every <paramlink id="sampling_interval"/> bytes of
11633             memory allocated by a given thread.
11634             <p/>
11635             Once the new sampling interval is taken into account, 0 as a sampling interval will generate
11636             a sample for every allocation.
11637             <p/>
11638             Note: The overhead of this feature is directly correlated with the sampling interval.
11639             A high sampling interval, such as 1024 bytes, will incur a high overhead.
11640             A lower interval, such as 1024KB, will have a much lower overhead.  Sampling should only
11641             be used with an understanding that it may impact performance.
11642           </description>
11643         </param>
11644       </parameters>
11645       <errors>
11646         <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
11647           <paramlink id="sampling_interval"></paramlink> is less than zero.
11648         </error>
11649       </errors>
11650     </function>
11651   </category>
11652 
11653 </functionsection>
11654 
11655 <errorsection label="Error Reference">
11656   <intro>
11657     Every <jvmti/> function returns a <b><code>jvmtiError</code></b> error code.
11658     <p/>
11659     It is the responsibility of the agent to call <jvmti/> functions with
11660     valid parameters and in the proper context (calling thread is attached,
11661     phase is correct, etc.).
11662     Detecting some error conditions may be difficult, inefficient, or
11663     impossible for an implementation.
11664     The errors listed in
11665     <internallink id="reqerrors">Function Specific Required Errors</internallink>
11666     must be detected by the implementation.
11667     All other errors represent the recommended response to the error
11668     condition.
11669   </intro>
11670 
11671   <errorcategory id="universal-error" label="Universal Errors">
11672     <intro>
11673       The following errors may be returned by any function
11674     </intro>
11675 
11676     <errorid id="JVMTI_ERROR_NONE" num="0">
11677       No error has occurred.  This is the error code that is returned
11678       on successful completion of the function.
11679     </errorid>
11680     <errorid id="JVMTI_ERROR_NULL_POINTER" num="100">
11681       Pointer is unexpectedly <code>NULL</code>.
11682     </errorid>
11683     <errorid id="JVMTI_ERROR_OUT_OF_MEMORY" num="110">
11684       The function attempted to allocate memory and no more memory was
11685       available for allocation.
11686     </errorid>
11687     <errorid id="JVMTI_ERROR_ACCESS_DENIED" num="111">
11688       The desired functionality has not been enabled in this virtual machine.
11689     </errorid>
11690     <errorid id="JVMTI_ERROR_UNATTACHED_THREAD" num="115">
11691       The thread being used to call this function is not attached
11692       to the virtual machine.  Calls must be made from attached threads.
11693       See <code>AttachCurrentThread</code> in the JNI invocation API.
11694     </errorid>
11695     <errorid id="JVMTI_ERROR_INVALID_ENVIRONMENT" num="116">
11696       The <jvmti/> environment provided is no longer connected or is
11697       not an environment.
11698     </errorid>
11699     <errorid id="JVMTI_ERROR_WRONG_PHASE" num="112">
11700       The desired functionality is not available in the current
11701         <functionlink id="GetPhase">phase</functionlink>.
11702       Always returned if the virtual machine has completed running.
11703     </errorid>
11704     <errorid id="JVMTI_ERROR_INTERNAL" num="113">
11705       An unexpected internal error has occurred.
11706     </errorid>
11707   </errorcategory>
11708 
11709   <errorcategory id="reqerrors" label="Function Specific Required Errors">
11710     <intro>
11711       The following errors are returned by some <jvmti/> functions and must
11712       be returned by the implementation when the condition occurs.
11713     </intro>
11714 
11715     <errorid id="JVMTI_ERROR_INVALID_PRIORITY" num="12">
11716       Invalid priority.
11717     </errorid>
11718     <errorid id="JVMTI_ERROR_THREAD_NOT_SUSPENDED" num="13">
11719       Thread was not suspended.
11720     </errorid>
11721     <errorid id="JVMTI_ERROR_THREAD_SUSPENDED" num="14">
11722       Thread already suspended.
11723     </errorid>
11724     <errorid id="JVMTI_ERROR_THREAD_NOT_ALIVE" num="15">
11725       This operation requires the thread to be alive--that is,
11726       it must be started and not yet have died.
11727     </errorid>
11728     <errorid id="JVMTI_ERROR_CLASS_NOT_PREPARED" num="22">
11729       The class has been loaded but not yet prepared.
11730     </errorid>
11731     <errorid id="JVMTI_ERROR_NO_MORE_FRAMES" num="31">
11732       There are no Java programming language or JNI stack frames at the specified depth.
11733     </errorid>
11734     <errorid id="JVMTI_ERROR_OPAQUE_FRAME" num="32">
11735       Information about the frame is not available (e.g. for native frames).
11736     </errorid>
11737     <errorid id="JVMTI_ERROR_DUPLICATE" num="40">
11738       Item already set.
11739     </errorid>
11740     <errorid id="JVMTI_ERROR_NOT_FOUND" num="41">
11741       Desired element (e.g. field or breakpoint) not found
11742     </errorid>
11743     <errorid id="JVMTI_ERROR_NOT_MONITOR_OWNER" num="51">
11744       This thread doesn't own the raw monitor.
11745     </errorid>
11746     <errorid id="JVMTI_ERROR_INTERRUPT" num="52">
11747       The call has been interrupted before completion.
11748     </errorid>
11749     <errorid id="JVMTI_ERROR_UNMODIFIABLE_CLASS" num="79">
11750       The class cannot be modified.
11751     </errorid>
11752     <errorid id="JVMTI_ERROR_UNMODIFIABLE_MODULE" num="80">
11753       The module cannot be modified.
11754     </errorid>
11755     <errorid id="JVMTI_ERROR_NOT_AVAILABLE" num="98">
11756       The functionality is not available in this virtual machine.
11757     </errorid>
11758     <errorid id="JVMTI_ERROR_ABSENT_INFORMATION" num="101">
11759       The requested information is not available.
11760     </errorid>
11761     <errorid id="JVMTI_ERROR_INVALID_EVENT_TYPE" num="102">
11762       The specified event type ID is not recognized.
11763     </errorid>
11764     <errorid id="JVMTI_ERROR_NATIVE_METHOD" num="104">
11765       The requested information is not available for native method.
11766     </errorid>
11767     <errorid id="JVMTI_ERROR_CLASS_LOADER_UNSUPPORTED" num="106">
11768       The class loader does not support this operation.
11769     </errorid>
11770   </errorcategory>
11771 
11772   <errorcategory id="function-specific-errors" label="Function Specific Agent Errors">
11773     <intro>
11774       The following errors are returned by some <jvmti/> functions.
11775       They are returned in the event of invalid parameters passed by the
11776       agent or usage in an invalid context.
11777       An implementation is not required to detect these errors.
11778     </intro>
11779 
11780     <errorid id="JVMTI_ERROR_INVALID_THREAD" num="10">
11781       The passed thread is not a valid thread.
11782     </errorid>
11783     <errorid id="JVMTI_ERROR_INVALID_FIELDID" num="25">
11784       Invalid field.
11785     </errorid>
11786     <errorid id="JVMTI_ERROR_INVALID_MODULE" num="26">
11787       Invalid module.
11788     </errorid>
11789     <errorid id="JVMTI_ERROR_INVALID_METHODID" num="23">
11790       Invalid method.
11791     </errorid>
11792     <errorid id="JVMTI_ERROR_INVALID_LOCATION" num="24">
11793       Invalid location.
11794     </errorid>
11795     <errorid id="JVMTI_ERROR_INVALID_OBJECT" num="20">
11796       Invalid object.
11797     </errorid>
11798     <errorid id="JVMTI_ERROR_INVALID_CLASS" num="21">
11799       Invalid class.
11800     </errorid>
11801     <errorid id="JVMTI_ERROR_TYPE_MISMATCH" num="34">
11802       The variable is not an appropriate type for the function used.
11803     </errorid>
11804     <errorid id="JVMTI_ERROR_INVALID_SLOT" num="35">
11805       Invalid slot.
11806     </errorid>
11807     <errorid id="JVMTI_ERROR_MUST_POSSESS_CAPABILITY" num="99">
11808       The capability being used is false in this environment.
11809     </errorid>
11810     <errorid id="JVMTI_ERROR_INVALID_THREAD_GROUP" num="11">
11811       Thread group invalid.
11812     </errorid>
11813     <errorid id="JVMTI_ERROR_INVALID_MONITOR" num="50">
11814       Invalid raw monitor.
11815     </errorid>
11816     <errorid id="JVMTI_ERROR_ILLEGAL_ARGUMENT" num="103">
11817       Illegal argument.
11818     </errorid>
11819     <errorid id="JVMTI_ERROR_INVALID_TYPESTATE" num="65">
11820       The state of the thread has been modified, and is now inconsistent.
11821     </errorid>
11822     <errorid id="JVMTI_ERROR_UNSUPPORTED_VERSION" num="68">
11823       A new class file has a version number not supported by this VM.
11824     </errorid>
11825     <errorid id="JVMTI_ERROR_INVALID_CLASS_FORMAT" num="60">
11826       A new class file is malformed (the VM would return a <code>ClassFormatError</code>).
11827     </errorid>
11828     <errorid id="JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION" num="61">
11829       The new class file definitions would lead to a circular
11830       definition (the VM would return a <code>ClassCircularityError</code>).
11831     </errorid>
11832     <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED" num="63">
11833       A new class file would require adding a method.
11834     </errorid>
11835     <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED" num="64">
11836       A new class version changes a field.
11837     </errorid>
11838     <errorid id="JVMTI_ERROR_FAILS_VERIFICATION" num="62">
11839       The class bytes fail verification.
11840     </errorid>
11841     <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED" num="66">
11842       A direct superclass is different for the new class
11843       version, or the set of directly implemented
11844       interfaces is different.
11845     </errorid>
11846     <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED" num="67">
11847       A new class version does not declare a method
11848       declared in the old class version.
11849     </errorid>
11850     <errorid id="JVMTI_ERROR_NAMES_DONT_MATCH" num="69">
11851       The class name defined in the new class file is
11852       different from the name in the old class object.
11853     </errorid>
11854     <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED" num="70">
11855       A new class version has different modifiers.
11856     </errorid>
11857     <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED" num="71">
11858       A method in the new class version has different modifiers
11859       than its counterpart in the old class version.
11860     </errorid>
11861     <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED" num="72">
11862       A new class version has unsupported differences in class attributes.
11863     </errorid>
11864   </errorcategory>
11865 </errorsection>
11866 
11867 <eventsection label="Events">
11868   <intro label="Handling Events" id="eventIntro">
11869     Agents can be informed of many events that occur in application
11870     programs.
11871     <p/>
11872     To handle events, designate a set of callback functions with
11873     <functionlink id="SetEventCallbacks"></functionlink>.
11874     For each event the corresponding callback function will be
11875     called.
11876     Arguments to the callback function provide additional
11877     information about the event.
11878     <p/>
11879     The callback function is usually called from within an application
11880     thread. The <jvmti/> implementation does not
11881     queue events in any way. This means
11882     that event callback functions must be written
11883     carefully. Here are some general guidelines. See
11884     the individual event descriptions for further
11885     suggestions.
11886     <p/>
11887     <ul>
11888       <li>Any exception thrown during the execution of an event callback can
11889         overwrite any current pending exception in the current application thread.
11890         Care must be taken to preserve a pending exception
11891         when an event callback makes a JNI call that might generate an exception.
11892       </li>
11893       <li>Event callback functions must be re-entrant. The <jvmti/> implementation does
11894         not queue events. If an agent needs to process events one at a time, it
11895         can use a raw monitor inside the
11896         event callback functions to serialize event processing.
11897       </li>
11898       <li>Event callback functions that execute JNI's FindClass function to load
11899         classes need to note that FindClass locates the class loader associated
11900         with the current native method. For the purposes of class loading, an
11901         event callback that includes a JNI environment as a parameter to the
11902         callback will treated as if it is a native call, where the native method
11903         is in the class of the event thread's current frame.
11904       </li>
11905     </ul>
11906     <p/>
11907     Some <jvmti/> events identify objects with JNI references.
11908     All references
11909     in <jvmti/> events are JNI local references and will become invalid
11910     after the event callback returns.
11911     Unless stated otherwise, memory referenced by pointers sent in event
11912     callbacks may not be referenced after the event callback returns.
11913     <p/>
11914     Except where stated otherwise, events are delivered on the thread
11915     that caused the event.
11916     Events are sent at the time they occur.
11917     The specification for each event includes the set of
11918     <functionlink id="GetPhase">phases</functionlink> in which it can be sent;
11919     if an event triggering activity occurs during another phase, no event
11920     is sent.
11921     <p/>
11922     A thread that generates an event does not change its execution status
11923     (for example, the event does not cause the thread to be suspended).
11924     If an agent wishes the event to result in suspension, then the agent
11925     is responsible for explicitly suspending the thread with
11926     <functionlink id="SuspendThread"></functionlink>.
11927     <p/>
11928     If an event is enabled in multiple environments, the event will be sent
11929     to each agent in the order that the environments were created.
11930   </intro>
11931 
11932   <intro label="Enabling Events" id="enablingevents">
11933     All events are initially disabled.  In order to receive any
11934     event:
11935       <ul>
11936         <li>
11937           If the event requires a capability, that capability must
11938           be added with
11939           <functionlink id="AddCapabilities"></functionlink>.
11940         </li>
11941         <li>
11942           A callback for the event must be set with
11943           <functionlink id="SetEventCallbacks"></functionlink>.
11944         </li>
11945         <li>
11946           The event must be enabled with
11947           <functionlink id="SetEventNotificationMode"></functionlink>.
11948         </li>
11949       </ul>
11950   </intro>
11951 
11952   <intro label="Multiple Co-located Events" id="eventorder">
11953     In many situations it is possible for multiple events to occur
11954     at the same location in one thread. When this happens, all the events
11955     are reported through the event callbacks in the order specified in this section.
11956     <p/>
11957     If the current location is at the entry point of a method, the
11958     <eventlink id="MethodEntry"></eventlink> event is reported before
11959     any other event at the current location in the same thread.
11960     <p/>
11961     If an exception catch has been detected at the current location,
11962     either because it is the beginning of a catch clause or a native method
11963     that cleared a pending exception has returned, the
11964     <code>exceptionCatch</code> event is reported before
11965     any other event at the current location in the same thread.
11966     <p/>
11967     If a <code>singleStep</code> event or
11968     <code>breakpoint</code> event is triggered at the
11969     current location, the event is defined to occur
11970     immediately before the code at the current location is executed.
11971     These events are reported before any events which are triggered
11972     by the execution of code at the current location in the same
11973     thread (specifically:
11974     <code>exception</code>,
11975     <code>fieldAccess</code>, and
11976     <code>fieldModification</code>).
11977     If both a step and breakpoint event are triggered for the same thread and
11978     location, the step event is reported before the breakpoint event.
11979     <p/>
11980     If the current location is the exit point of a method (that is, the last
11981     location before returning to the caller), the
11982     <eventlink id="MethodExit"></eventlink> event and
11983     the <eventlink id="FramePop"></eventlink> event (if requested)
11984     are reported after all other events at the current location in the same
11985     thread. There is no specified ordering of these two events
11986     with respect to each other.
11987     <p/>
11988     Co-located events can be triggered during the processing of some other
11989     event by the agent at the same location in the same thread.
11990     If such an event, of type <i>y</i>, is triggered during the processing of
11991     an event of type <i>x</i>, and if <i>x</i>
11992     precedes <i>y</i> in the ordering specified above, the co-located event
11993     <i>y</i> is reported for the current thread and location. If <i>x</i> does not precede
11994     <i>y</i>, <i>y</i> is not reported for the current thread and location.
11995     For example, if a breakpoint is set at the current location
11996     during the processing of <eventlink id="SingleStep"></eventlink>,
11997     that breakpoint will be reported before the thread moves off the current
11998     location.
11999     <p/>The following events are never considered to be co-located with
12000     other events.
12001     <ul>
12002       <li><eventlink id="VMStart"></eventlink></li>
12003       <li><eventlink id="VMInit"></eventlink></li>
12004       <li><eventlink id="VMDeath"></eventlink></li>
12005       <li><eventlink id="ThreadStart"></eventlink></li>
12006       <li><eventlink id="ThreadEnd"></eventlink></li>
12007       <li><eventlink id="ClassLoad"></eventlink></li>
12008       <li><eventlink id="ClassPrepare"></eventlink></li>
12009     </ul>
12010   </intro>
12011 
12012   <intro label="Event Callbacks" id="jvmtiEventCallbacks">
12013       The event callback structure below is used to specify the handler function
12014       for events.  It is set with the
12015       <functionlink id="SetEventCallbacks"></functionlink> function.
12016   </intro>
12017 
12018   <event label="Single Step"
12019          id="SingleStep" const="JVMTI_EVENT_SINGLE_STEP" filtered="thread" num="60">
12020     <description>
12021       Single step events allow the agent to trace thread execution
12022       at the finest granularity allowed by the VM. A single step event is
12023       generated whenever a thread reaches a new location.
12024       Typically, single step events represent the completion of one VM
12025       instruction as defined in <vmspec/>. However, some implementations
12026       may define locations differently. In any case the
12027       <code>method</code> and <code>location</code>
12028       parameters  uniquely identify the current location and allow
12029       the mapping to source file and line number when that information is
12030       available.
12031       <p/>
12032       No single step events are generated from within native methods.
12033     </description>
12034     <origin>jvmdi</origin>
12035     <capabilities>
12036       <required id="can_generate_single_step_events"></required>
12037     </capabilities>
12038     <parameters>
12039       <param id="jni_env">
12040         <outptr>
12041           <struct>JNIEnv</struct>
12042         </outptr>
12043           <description>
12044             The JNI environment of the event (current) thread
12045           </description>
12046       </param>
12047       <param id="thread">
12048         <jthread/>
12049           <description>
12050             Thread about to execution a new instruction
12051           </description>
12052       </param>
12053       <param id="klass">
12054         <jclass method="method"/>
12055           <description>
12056             Class of the method about to execute a new instruction
12057           </description>
12058       </param>
12059       <param id="method">
12060         <jmethodID class="klass"/>
12061           <description>
12062             Method about to execute a new instruction
12063           </description>
12064       </param>
12065       <param id="location">
12066         <jlocation/>
12067         <description>
12068           Location of the new instruction
12069         </description>
12070       </param>
12071     </parameters>
12072   </event>
12073 
12074   <event label="Breakpoint"
12075          id="Breakpoint" const="JVMTI_EVENT_BREAKPOINT" filtered="thread" num="62">
12076     <description>
12077       Breakpoint events are generated whenever a thread reaches a location
12078       designated as a breakpoint with <functionlink id="SetBreakpoint"></functionlink>.
12079       The <code>method</code> and <code>location</code>
12080       parameters uniquely identify the current location and allow
12081       the mapping to source file and line number when that information is
12082       available.
12083     </description>
12084     <origin>jvmdi</origin>
12085     <capabilities>
12086       <required id="can_generate_breakpoint_events"></required>
12087     </capabilities>
12088     <parameters>
12089       <param id="jni_env">
12090         <outptr>
12091           <struct>JNIEnv</struct>
12092         </outptr>
12093           <description>
12094             The JNI environment of the event (current) thread.
12095           </description>
12096       </param>
12097       <param id="thread">
12098         <jthread/>
12099           <description>
12100             Thread that hit the breakpoint
12101           </description>
12102       </param>
12103       <param id="klass">
12104         <jclass method="method"/>
12105           <description>
12106             Class of the method that hit the breakpoint
12107           </description>
12108       </param>
12109       <param id="method">
12110         <jmethodID class="klass"/>
12111           <description>
12112             Method that hit the breakpoint
12113           </description>
12114       </param>
12115       <param id="location">
12116         <jlocation/>
12117         <description>
12118           location of the breakpoint
12119         </description>
12120       </param>
12121     </parameters>
12122   </event>
12123 
12124   <event label="Field Access"
12125          id="FieldAccess" const="JVMTI_EVENT_FIELD_ACCESS" filtered="thread" num="63">
12126     <description>
12127       Field access events are generated whenever a thread accesses
12128       a field that was designated as a watchpoint
12129       with <functionlink id="SetFieldAccessWatch"></functionlink>.
12130       The <code>method</code> and <code>location</code>
12131       parameters uniquely identify the current location and allow
12132       the mapping to source file and line number when that information is
12133       available.
12134     </description>
12135     <origin>jvmdi</origin>
12136     <capabilities>
12137       <required id="can_generate_field_access_events"></required>
12138     </capabilities>
12139     <parameters>
12140       <param id="jni_env">
12141         <outptr>
12142           <struct>JNIEnv</struct>
12143         </outptr>
12144           <description>
12145             The JNI environment of the event (current) thread
12146           </description>
12147       </param>
12148       <param id="thread">
12149         <jthread/>
12150           <description>
12151             Thread accessing the field
12152           </description>
12153       </param>
12154       <param id="klass">
12155         <jclass method="method"/>
12156           <description>
12157             Class of the method where the access is occurring
12158           </description>
12159       </param>
12160       <param id="method">
12161         <jmethodID class="klass"/>
12162           <description>
12163             Method where the access is occurring
12164           </description>
12165       </param>
12166       <param id="location">
12167         <jlocation/>
12168         <description>
12169           Location where the access is occurring
12170         </description>
12171       </param>
12172       <param id="field_klass">
12173         <jclass field="field"/>
12174           <description>
12175             Class of the field being accessed
12176           </description>
12177       </param>
12178       <param id="object">
12179         <jobject/>
12180           <description>
12181             Object with the field being accessed if the field is an
12182             instance field; <code>NULL</code> otherwise
12183           </description>
12184       </param>
12185       <param id="field">
12186         <jfieldID class="field_klass"/>
12187           <description>
12188             Field being accessed
12189           </description>
12190       </param>
12191     </parameters>
12192   </event>
12193 
12194   <event label="Field Modification"
12195          id="FieldModification" const="JVMTI_EVENT_FIELD_MODIFICATION" filtered="thread" num="64">
12196     <description>
12197       Field modification events are generated whenever a thread modifies
12198       a field that was designated as a watchpoint
12199       with <functionlink id="SetFieldModificationWatch"></functionlink>.
12200       The <code>method</code> and <code>location</code>
12201       parameters uniquely identify the current location and allow
12202       the mapping to source file and line number when that information is
12203       available.
12204     </description>
12205     <origin>jvmdi</origin>
12206     <capabilities>
12207       <required id="can_generate_field_modification_events"></required>
12208     </capabilities>
12209     <parameters>
12210       <param id="jni_env">
12211         <outptr>
12212           <struct>JNIEnv</struct>
12213         </outptr>
12214           <description>
12215             The JNI environment of the event (current) thread
12216           </description>
12217       </param>
12218       <param id="thread">
12219         <jthread/>
12220           <description>
12221             Thread modifying the field
12222           </description>
12223       </param>
12224       <param id="klass">
12225         <jclass method="method"/>
12226           <description>
12227             Class of the method where the modification is occurring
12228           </description>
12229       </param>
12230       <param id="method">
12231         <jmethodID class="klass"/>
12232           <description>
12233             Method where the modification is occurring
12234           </description>
12235       </param>
12236       <param id="location">
12237         <jlocation/>
12238         <description>
12239           Location where the modification is occurring
12240         </description>
12241       </param>
12242       <param id="field_klass">
12243         <jclass field="field"/>
12244           <description>
12245             Class of the field being modified
12246           </description>
12247       </param>
12248       <param id="object">
12249         <jobject/>
12250           <description>
12251             Object with the field being modified if the field is an
12252             instance field; <code>NULL</code> otherwise
12253           </description>
12254       </param>
12255       <param id="field">
12256         <jfieldID class="field_klass"/>
12257           <description>
12258             Field being modified
12259           </description>
12260       </param>
12261       <param id="signature_type">
12262         <char/>
12263         <description>
12264           Signature type of the new value
12265         </description>
12266       </param>
12267       <param id="new_value">
12268         <jvalue/>
12269         <description>
12270           The new value
12271         </description>
12272       </param>
12273     </parameters>
12274   </event>
12275 
12276   <event label="Frame Pop"
12277          id="FramePop" const="JVMTI_EVENT_FRAME_POP" filtered="thread" num="61">
12278     <description>
12279       Frame pop events are generated upon exit from a single method
12280       in a single frame as specified
12281       in a call to <functionlink id="NotifyFramePop"></functionlink>.
12282       This is true whether termination is caused by
12283       executing its return instruction
12284       or by throwing an exception to its caller
12285       (see <paramlink id="was_popped_by_exception"></paramlink>).
12286       However, frame pops caused by the <functionlink id="PopFrame"/>
12287       function are not reported.
12288       <p/>
12289       The location reported by <functionlink id="GetFrameLocation"></functionlink>
12290       identifies the executable location in the returning method,
12291       immediately prior to the return.
12292     </description>
12293     <origin>jvmdi</origin>
12294     <capabilities>
12295       <required id="can_generate_frame_pop_events"></required>
12296     </capabilities>
12297     <parameters>
12298       <param id="jni_env">
12299         <outptr>
12300           <struct>JNIEnv</struct>
12301         </outptr>
12302           <description>
12303             The JNI environment of the event (current) thread
12304           </description>
12305       </param>
12306       <param id="thread">
12307         <jthread/>
12308           <description>
12309             Thread that is popping the frame
12310           </description>
12311       </param>
12312       <param id="klass">
12313         <jclass method="method"/>
12314           <description>
12315             Class of the method being popped
12316           </description>
12317       </param>
12318       <param id="method">
12319         <jmethodID class="klass"/>
12320           <description>
12321             Method being popped
12322           </description>
12323       </param>
12324       <param id="was_popped_by_exception">
12325         <jboolean/>
12326         <description>
12327           True if frame was popped by a thrown exception.
12328           False if method exited through its return instruction.
12329         </description>
12330       </param>
12331     </parameters>
12332   </event>
12333 
12334   <event label="Method Entry"
12335          id="MethodEntry" const="JVMTI_EVENT_METHOD_ENTRY" filtered="thread" num="65">
12336     <description>
12337       Method entry events are generated upon entry of Java
12338       programming language methods (including native methods).
12339       <p/>
12340       The location reported by <functionlink id="GetFrameLocation"></functionlink>
12341       identifies the initial executable location in
12342       the method.
12343       <p/>
12344       Enabling method
12345       entry or exit events will significantly degrade performance on many platforms and is thus
12346       not advised for performance critical usage (such as profiling).
12347       <internallink id="bci">Bytecode instrumentation</internallink> should be
12348       used in these cases.
12349     </description>
12350     <origin>jvmdi</origin>
12351     <capabilities>
12352       <required id="can_generate_method_entry_events"></required>
12353     </capabilities>
12354     <parameters>
12355       <param id="jni_env">
12356         <outptr>
12357           <struct>JNIEnv</struct>
12358         </outptr>
12359           <description>
12360             The JNI environment of the event (current) thread
12361           </description>
12362       </param>
12363       <param id="thread">
12364         <jthread/>
12365           <description>
12366             Thread entering the method
12367           </description>
12368       </param>
12369       <param id="klass">
12370         <jclass method="method"/>
12371           <description>
12372             Class of the method being entered
12373           </description>
12374       </param>
12375       <param id="method">
12376         <jmethodID class="klass"/>
12377           <description>
12378             Method being entered
12379           </description>
12380       </param>
12381     </parameters>
12382   </event>
12383 
12384   <event label="Method Exit"
12385          id="MethodExit" const="JVMTI_EVENT_METHOD_EXIT" filtered="thread" num="66">
12386     <description>
12387       Method exit events are generated upon exit from Java
12388       programming language methods (including native methods).
12389       This is true whether termination is caused by
12390       executing its return instruction
12391       or by throwing an exception to its caller
12392       (see <paramlink id="was_popped_by_exception"></paramlink>).
12393       <p/>
12394       The <code>method</code> field uniquely identifies the
12395       method being entered or exited. The <code>frame</code> field provides
12396       access to the stack frame for the method.
12397       <p/>
12398       The location reported by <functionlink id="GetFrameLocation"></functionlink>
12399       identifies the executable location in the returning method
12400       immediately prior to the return.
12401       <p/>
12402         Enabling method
12403         entry or exit events will significantly degrade performance on many platforms and is thus
12404         not advised for performance critical usage (such as profiling).
12405         <internallink id="bci">Bytecode instrumentation</internallink> should be
12406         used in these cases.
12407     </description>
12408     <origin>jvmdi</origin>
12409     <capabilities>
12410       <required id="can_generate_method_exit_events"></required>
12411     </capabilities>
12412     <parameters>
12413       <param id="jni_env">
12414         <outptr>
12415           <struct>JNIEnv</struct>
12416         </outptr>
12417           <description>
12418             The JNI environment of the event (current) thread
12419           </description>
12420       </param>
12421       <param id="thread">
12422         <jthread/>
12423           <description>
12424             Thread exiting the method
12425           </description>
12426       </param>
12427       <param id="klass">
12428         <jclass method="method"/>
12429           <description>
12430             Class of the method being exited
12431           </description>
12432       </param>
12433       <param id="method">
12434         <jmethodID class="klass"/>
12435           <description>
12436             Method being exited
12437           </description>
12438       </param>
12439       <param id="was_popped_by_exception">
12440         <jboolean/>
12441         <description>
12442           True if frame was popped by a thrown exception.
12443           False if method exited through its return instruction.
12444         </description>
12445       </param>
12446       <param id="return_value">
12447         <jvalue/>
12448         <description>
12449           The return value of the method being exited.
12450           Undefined and should not be used if
12451           <paramlink id="was_popped_by_exception"></paramlink>
12452           is true.
12453         </description>
12454       </param>
12455     </parameters>
12456   </event>
12457 
12458   <event label="Native Method Bind" phase="any"
12459          id="NativeMethodBind" const="JVMTI_EVENT_NATIVE_METHOD_BIND" num="67">
12460     <description>
12461       A Native Method Bind event is sent when a VM binds a
12462       Java programming language native method
12463       to the address of a function that implements the native method.
12464       This will occur when the native method is called for the first time
12465       and also occurs when the JNI function <code>RegisterNatives</code> is called.
12466       This event allows the bind to be redirected to an agent-specified
12467       proxy function.
12468       This event is not sent when the native method is unbound.
12469       Typically, this proxy function will need to be specific to a
12470       particular method or, to handle the general case, automatically
12471       generated assembly code, since after instrumentation code is
12472       executed the function at the original binding
12473       address will usually be invoked.
12474       The original binding can be restored or the redirection changed
12475       by use of the JNI function <code>RegisterNatives</code>.
12476       Some events may be sent during the primordial phase, JNI and
12477       most of <jvmti/> cannot be used at this time but the method and
12478       address can be saved for use later.
12479     </description>
12480     <origin>new</origin>
12481     <capabilities>
12482       <required id="can_generate_native_method_bind_events"></required>
12483     </capabilities>
12484     <parameters>
12485       <param id="jni_env">
12486         <outptr>
12487           <struct>JNIEnv</struct>
12488         </outptr>
12489           <description>
12490             The JNI environment of the event (current) thread
12491             Will be <code>NULL</code> if sent during the primordial
12492             <functionlink id="GetPhase">phase</functionlink>.
12493           </description>
12494       </param>
12495       <param id="thread">
12496         <jthread/>
12497           <description>
12498             Thread requesting the bind
12499           </description>
12500       </param>
12501       <param id="klass">
12502         <jclass method="method"/>
12503           <description>
12504             Class of the method being bound
12505           </description>
12506       </param>
12507       <param id="method">
12508         <jmethodID class="klass"/>
12509           <description>
12510             Native method being bound
12511           </description>
12512       </param>
12513       <param id="address">
12514         <outptr><void/></outptr>
12515         <description>
12516           The address the VM is about to bind to--that is, the
12517           address of the implementation of the native method
12518         </description>
12519       </param>
12520       <param id="new_address_ptr">
12521         <agentbuf><void/></agentbuf>
12522         <description>
12523           if the referenced address is changed (that is, if
12524           <code>*new_address_ptr</code> is set), the binding
12525           will instead be made to the supplied address.
12526         </description>
12527       </param>
12528     </parameters>
12529   </event>
12530 
12531   <event label="Exception"
12532          id="Exception" const="JVMTI_EVENT_EXCEPTION" filtered="thread" num="58">
12533     <description>
12534       Exception events are generated whenever an exception is first detected
12535       in a Java programming language method.
12536       Where "exception" means any <code>java.lang.Throwable</code>.
12537       The exception may have been thrown by a Java programming language or native
12538       method, but in the case of native methods, the event is not generated
12539       until the exception is first seen by a Java programming language method. If an exception is
12540       set and cleared in a native method (and thus is never visible to Java programming language code),
12541       no exception event is generated.
12542       <p/>
12543       The <code>method</code> and <code>location</code>
12544       parameters  uniquely identify the current location
12545       (where the exception was detected) and allow
12546       the mapping to source file and line number when that information is
12547       available. The <code>exception</code> field identifies the thrown
12548       exception object. The <code>catch_method</code>
12549       and <code>catch_location</code> identify the location of the catch clause,
12550       if any, that handles the thrown exception. If there is no such catch clause,
12551       each field is set to 0. There is no guarantee that the thread will ever
12552       reach this catch clause. If there are native methods on the call stack
12553       between the throw location and the catch clause, the exception may
12554       be reset by one of those native methods.
12555       Similarly, exceptions that are reported as uncaught (<code>catch_klass</code>
12556       et al. set to 0) may in fact be caught by native code.
12557       Agents can check for these occurrences by monitoring
12558       <eventlink id="ExceptionCatch"></eventlink> events.
12559       Note that finally clauses are implemented as catch and re-throw. Therefore they
12560       will be reported in the catch location.
12561     </description>
12562     <origin>jvmdi</origin>
12563     <capabilities>
12564       <required id="can_generate_exception_events"></required>
12565     </capabilities>
12566     <parameters>
12567       <param id="jni_env">
12568         <outptr>
12569           <struct>JNIEnv</struct>
12570         </outptr>
12571           <description>
12572             The JNI environment of the event (current) thread
12573           </description>
12574       </param>
12575       <param id="thread">
12576         <jthread/>
12577           <description>
12578             Thread generating the exception
12579           </description>
12580       </param>
12581       <param id="klass">
12582         <jclass method="method"/>
12583           <description>
12584             Class generating the exception
12585           </description>
12586       </param>
12587       <param id="method">
12588         <jmethodID class="klass"/>
12589           <description>
12590             Method generating the exception
12591           </description>
12592       </param>
12593       <param id="location">
12594         <jlocation/>
12595         <description>
12596           Location where exception occurred
12597         </description>
12598       </param>
12599       <param id="exception">
12600         <jobject/>
12601           <description>
12602             The exception being thrown
12603           </description>
12604       </param>
12605       <param id="catch_klass">
12606         <jclass method="catch_method"/>
12607           <description>
12608             Class that will catch the exception, or <code>NULL</code> if no known catch
12609           </description>
12610       </param>
12611       <param id="catch_method">
12612         <jmethodID class="catch_klass"/>
12613           <description>
12614             Method that will catch the exception, or <code>NULL</code> if no known catch
12615           </description>
12616       </param>
12617       <param id="catch_location">
12618         <jlocation/>
12619         <description>
12620           location which will catch the exception or zero if no known catch
12621         </description>
12622       </param>
12623     </parameters>
12624   </event>
12625 
12626   <event label="Exception Catch"
12627          id="ExceptionCatch" const="JVMTI_EVENT_EXCEPTION_CATCH" filtered="thread" num="59">
12628     <description>
12629       Exception catch events are generated whenever a thrown exception is caught.
12630       Where "exception" means any <code>java.lang.Throwable</code>.
12631       If the exception is caught in a Java programming language method, the event is generated
12632       when the catch clause is reached. If the exception is caught in a native
12633       method, the event is generated as soon as control is returned to a Java programming language
12634       method. Exception catch events are generated for any exception for which
12635       a throw was detected in a Java programming language method.
12636       Note that finally clauses are implemented as catch and re-throw. Therefore they
12637       will generate exception catch events.
12638       <p/>
12639       The <code>method</code> and <code>location</code>
12640       parameters uniquely identify the current location
12641       and allow the mapping to source file and line number when that information is
12642       available. For exceptions caught in a Java programming language method, the
12643       <code>exception</code> object identifies the exception object. Exceptions
12644       caught in native methods are not necessarily available by the time the
12645       exception catch is reported, so the <code>exception</code> field is set
12646       to <code>NULL</code>.
12647     </description>
12648     <origin>jvmdi</origin>
12649     <capabilities>
12650       <required id="can_generate_exception_events"></required>
12651     </capabilities>
12652     <parameters>
12653       <param id="jni_env">
12654         <outptr>
12655           <struct>JNIEnv</struct>
12656         </outptr>
12657           <description>
12658             The JNI environment of the event (current) thread
12659           </description>
12660       </param>
12661       <param id="thread">
12662         <jthread/>
12663           <description>
12664             Thread catching the exception
12665           </description>
12666       </param>
12667       <param id="klass">
12668         <jclass method="method"/>
12669           <description>
12670             Class catching the exception
12671           </description>
12672       </param>
12673       <param id="method">
12674         <jmethodID class="klass"/>
12675           <description>
12676             Method catching the exception
12677           </description>
12678       </param>
12679       <param id="location">
12680         <jlocation/>
12681         <description>
12682           Location where exception is being caught
12683         </description>
12684       </param>
12685       <param id="exception">
12686         <jobject/>
12687           <description>
12688             Exception being caught
12689           </description>
12690       </param>
12691     </parameters>
12692   </event>
12693 
12694   <event label="Thread Start"
12695          id="ThreadStart" const="JVMTI_EVENT_THREAD_START" num="52" phase="start">
12696     <description>
12697       Thread start events are generated by a new thread before its initial
12698       method executes.
12699       <p/>
12700       A thread may be listed in the array returned by
12701       <functionlink id="GetAllThreads"></functionlink>
12702       before its thread start event is generated.
12703       It is possible for other events to be generated
12704       on a thread before its thread start event.
12705       <p/>
12706       The event is sent on the newly started <paramlink id="thread"></paramlink>.
12707     </description>
12708     <origin>jvmdi</origin>
12709     <capabilities>
12710     </capabilities>
12711     <parameters>
12712       <param id="jni_env">
12713         <outptr>
12714           <struct>JNIEnv</struct>
12715         </outptr>
12716           <description>
12717             The JNI environment of the event (current) thread.
12718           </description>
12719       </param>
12720       <param id="thread">
12721         <jthread/>
12722           <description>
12723             Thread starting
12724           </description>
12725       </param>
12726     </parameters>
12727   </event>
12728 
12729   <event label="Thread End"
12730          id="ThreadEnd" const="JVMTI_EVENT_THREAD_END" filtered="thread" num="53" phase="start">
12731     <description>
12732       Thread end events are generated by a terminating thread
12733       after its initial method has finished execution.
12734       <p/>
12735       A thread may be listed in the array returned by
12736       <functionlink id="GetAllThreads"></functionlink>
12737       after its thread end event is generated.
12738       No events are generated on a thread
12739       after its thread end event.
12740       <p/>
12741       The event is sent on the dying <paramlink id="thread"></paramlink>.
12742     </description>
12743     <origin>jvmdi</origin>
12744     <capabilities>
12745     </capabilities>
12746     <parameters>
12747       <param id="jni_env">
12748         <outptr>
12749           <struct>JNIEnv</struct>
12750         </outptr>
12751           <description>
12752             The JNI environment of the event (current) thread.
12753           </description>
12754       </param>
12755       <param id="thread">
12756         <jthread/>
12757           <description>
12758             Thread ending
12759           </description>
12760       </param>
12761     </parameters>
12762   </event>
12763 
12764   <event label="Class Load"
12765          id="ClassLoad" const="JVMTI_EVENT_CLASS_LOAD" filtered="thread" phase="start" num="55">
12766     <description>
12767       A class load event is generated when a class or interface is created.
12768       A class or interface is created by one of the following:
12769       <ul>
12770       <li>By loading and deriving a class from a <code>class</code> file representation
12771           using class loader.</li>
12772       <li>By invoking <externallink id="../api/java.base/java/lang/invoke/MethodHandles.Lookup.html#defineHiddenClass(byte[],boolean,java.lang.invoke.MethodHandles.Lookup.ClassOption...)">Lookup::defineHiddenClass</externallink>,
12773           that creates a hidden class or interface from a <code>class</code> file representation.</li>
12774       <li>By invoking methods in certain Java SE Platform API such as reflection.</li>
12775       </ul>
12776       <p/>
12777       Array class creation does not generate a class load event.
12778       The creation of a primitive class (for example, java.lang.Integer.TYPE)
12779       does not generate a class load event.
12780       <p/>
12781       The order of class load events generated by a particular thread is guaranteed
12782       to match the order of class loading within that thread.
12783       <p/>
12784       This event is sent at an early stage in loading the class. As
12785       a result the class should be used carefully.  Note, for example,
12786       that methods and fields are not yet loaded, so queries for methods,
12787       fields, subclasses, and so on will not give correct results.
12788       See "Loading of Classes and Interfaces" in the <i>Java Language
12789       Specification</i>.  For most
12790       purposes the <eventlink id="ClassPrepare"></eventlink> event will
12791       be more useful.
12792       <p/>
12793       See <functionlink id="GetLoadedClasses">GetLoadedClasses</functionlink>.
12794     </description>
12795     <origin>jvmdi</origin>
12796     <capabilities>
12797     </capabilities>
12798     <parameters>
12799       <param id="jni_env">
12800         <outptr>
12801           <struct>JNIEnv</struct>
12802         </outptr>
12803           <description>
12804             The JNI environment of the event (current) thread
12805           </description>
12806       </param>
12807       <param id="thread">
12808         <jthread/>
12809           <description>
12810             Thread loading the class
12811           </description>
12812       </param>
12813       <param id="klass">
12814         <jclass/>
12815           <description>
12816             Class being loaded
12817           </description>
12818       </param>
12819     </parameters>
12820   </event>
12821 
12822   <elide>
12823   <event label="Class Unload"
12824          id="ClassUnload" const="JVMTI_EVENT_CLASS_UNLOAD" num="57">
12825     <description>
12826       A class unload event is generated when the class is about to be unloaded.
12827       Class unload events take place during garbage collection and must be
12828       handled extremely carefully. The garbage collector holds many locks
12829       and has suspended all other threads, so the event handler cannot depend
12830       on the ability to acquire any locks. The class unload event handler should
12831       do as little as possible, perhaps by queuing information to be processed
12832       later.  In particular, the <code>jclass</code> should be used only in
12833       the JNI function <code>isSameObject</code> or in the following <jvmti/> functions:
12834       <ul>
12835         <li><functionlink id="GetClassSignature"></functionlink></li>
12836         <li><functionlink id="GetSourceFileName"></functionlink></li>
12837         <li><functionlink id="IsInterface"></functionlink></li>
12838         <li><functionlink id="IsArrayClass"></functionlink></li>
12839       </ul>
12840     </description>
12841     <origin>jvmdi</origin>
12842     <capabilities>
12843     </capabilities>
12844     <parameters>
12845       <param id="jni_env">
12846         <outptr>
12847           <struct>JNIEnv</struct>
12848         </outptr>
12849           <description>
12850             The JNI environment of the event (current) thread
12851           </description>
12852       </param>
12853       <param id="thread">
12854         <jthread/>
12855           <description>
12856             Thread generating the class unload
12857           </description>
12858       </param>
12859       <param id="klass">
12860         <jclass/>
12861           <description>
12862             Class being unloaded
12863           </description>
12864       </param>
12865     </parameters>
12866   </event>
12867   </elide>
12868 
12869   <event label="Class Prepare"
12870          id="ClassPrepare" const="JVMTI_EVENT_CLASS_PREPARE" filtered="thread" phase="start" num="56">
12871     <description>
12872       A class prepare event is generated when class preparation is complete.
12873       At this point, class fields, methods, and implemented interfaces are
12874       available, and no code from the class has been executed. Since array
12875       classes never have fields or methods, class prepare events are not
12876       generated for them. Class prepare events are not generated for
12877       primitive classes (for example, <code>java.lang.Integer.TYPE</code>).
12878     </description>
12879     <origin>jvmdi</origin>
12880     <capabilities>
12881     </capabilities>
12882     <parameters>
12883       <param id="jni_env">
12884         <outptr>
12885           <struct>JNIEnv</struct>
12886         </outptr>
12887           <description>
12888             The JNI environment of the event (current) thread
12889           </description>
12890       </param>
12891       <param id="thread">
12892         <jthread/>
12893           <description>
12894             Thread generating the class prepare
12895           </description>
12896       </param>
12897       <param id="klass">
12898         <jclass/>
12899           <description>
12900             Class being prepared
12901           </description>
12902       </param>
12903     </parameters>
12904   </event>
12905 
12906   <event label="Class File Load Hook" phase="any"
12907          id="ClassFileLoadHook" const="JVMTI_EVENT_CLASS_FILE_LOAD_HOOK" num="54">
12908     <description>
12909       This event is sent when the VM obtains class file data,
12910       but before it constructs
12911       the in-memory representation for that class.
12912       This event is also sent when the class is being modified by the
12913       <functionlink id="RetransformClasses"/> function or
12914       the <functionlink id="RedefineClasses"/> function,
12915       called in any <jvmti/> environment.
12916       The agent can instrument
12917       the existing class file data sent by the VM to include profiling/debugging hooks.
12918       See the description of
12919       <internallink id="bci">bytecode instrumentation</internallink>
12920       for usage information.
12921       <p/>
12922     When the capabilities
12923     <internallink id="jvmtiCapabilities.can_generate_early_class_hook_events">
12924     <code>can_generate_early_class_hook_events</code></internallink> and
12925     <internallink id="jvmtiCapabilities.can_generate_all_class_hook_events">
12926     <code>can_generate_all_class_hook_events</code></internallink>
12927     are enabled then this event may be sent in the primordial phase.
12928     Otherwise, this event may be sent before the VM is initialized (the start
12929     <functionlink id="GetPhase">phase</functionlink>).
12930     Some classes might not be compatible
12931     with the function (eg. ROMized classes or implementation defined classes) and this event will
12932     not be generated for these classes.
12933     <p/>
12934     The agent must allocate the space for the modified
12935     class file data buffer
12936     using the memory allocation function
12937     <functionlink id="Allocate"></functionlink> because the
12938     VM is responsible for freeing the new class file data buffer
12939     using <functionlink id="Deallocate"></functionlink>.
12940     <p/>
12941     If the agent wishes to modify the class file, it must set
12942     <code>new_class_data</code> to point
12943     to the newly instrumented class file data buffer and set
12944     <code>new_class_data_len</code> to the length of that
12945     buffer before returning
12946     from this call.  If no modification is desired, the agent simply
12947     does not set <code>new_class_data</code>.  If multiple agents
12948     have enabled this event the results are chained. That is, if
12949     <code>new_class_data</code> has been set, it becomes the
12950     <code>class_data</code> for the next agent.
12951     <p/>
12952     When handling a class load in the live phase, then the
12953     <functionlink id="GetNamedModule"></functionlink>
12954     function can be used to map class loader and a package name to a module.
12955     When a class is being redefined or retransformed then
12956     <code>class_being_redefined</code> is non <code>NULL</code> and so
12957     the JNI <code>GetModule</code> function can also be used
12958     to obtain the Module.
12959     <p/>
12960     The order that this event is sent to each environment differs
12961     from other events.
12962     This event is sent to environments in the following order:
12963     <ul>
12964       <li><fieldlink id="can_retransform_classes"
12965                      struct="jvmtiCapabilities">retransformation
12966                                                 incapable</fieldlink>
12967           environments, in the
12968           order in which they were created
12969       </li>
12970       <li><fieldlink id="can_retransform_classes"
12971                      struct="jvmtiCapabilities">retransformation
12972                                                 capable</fieldlink>
12973           environments, in the
12974           order in which they were created
12975       </li>
12976     </ul>
12977     When triggered by <functionlink id="RetransformClasses"/>,
12978     this event is sent only to <fieldlink id="can_retransform_classes"
12979                      struct="jvmtiCapabilities">retransformation
12980                                                 capable</fieldlink>
12981     environments.
12982   </description>
12983   <origin>jvmpi</origin>
12984     <capabilities>
12985       <capability id="can_generate_all_class_hook_events"></capability>
12986       <capability id="can_generate_early_class_hook_events"></capability>
12987     </capabilities>
12988     <parameters>
12989       <param id="jni_env">
12990         <outptr>
12991           <struct>JNIEnv</struct>
12992         </outptr>
12993           <description>
12994             The JNI environment of the event (current) thread.
12995           </description>
12996       </param>
12997       <param id="class_being_redefined">
12998         <jclass/>
12999         <description>
13000           The class being
13001           <functionlink id="RedefineClasses">redefined</functionlink> or
13002           <functionlink id="RetransformClasses">retransformed</functionlink>.
13003           <code>NULL</code> if sent by class load.
13004         </description>
13005       </param>
13006       <param id="loader">
13007         <jobject/>
13008           <description>
13009             The class loader loading the class.
13010             <code>NULL</code> if the bootstrap class loader.
13011           </description>
13012       </param>
13013       <param id="name">
13014         <vmbuf><char/></vmbuf>
13015         <description>
13016             Name of class being loaded as a VM internal qualified name
13017             (for example, "java/util/List"), encoded as a
13018             <internallink id="mUTF">modified UTF-8</internallink> string.
13019             Note: if the class is defined with a <code>NULL</code> name or
13020             without a name specified, <code>name</code> will be <code>NULL</code>.
13021         </description>
13022       </param>
13023       <param id="protection_domain">
13024         <jobject/>
13025         <description>
13026           The <code>ProtectionDomain</code> of the class.
13027         </description>
13028       </param>
13029       <param id="class_data_len">
13030         <jint/>
13031         <description>
13032           Length of current class file data buffer.
13033         </description>
13034       </param>
13035       <param id="class_data">
13036         <vmbuf><uchar/></vmbuf>
13037         <description>
13038           Pointer to the current class file data buffer.
13039         </description>
13040       </param>
13041       <param id="new_class_data_len">
13042         <outptr><jint/></outptr>
13043         <description>
13044           Pointer to the length of the new class file data buffer.
13045         </description>
13046       </param>
13047       <param id="new_class_data">
13048         <agentbuf incount="new_class_data_len"><uchar/></agentbuf>
13049         <description>
13050           Pointer to the pointer to the instrumented class file data buffer.
13051         </description>
13052       </param>
13053     </parameters>
13054   </event>
13055 
13056   <event label="VM Start Event"
13057          id="VMStart" const="JVMTI_EVENT_VM_START" num="57" phase="start">
13058     <description>
13059       The VM start event signals the start of the VM.
13060       At this time JNI is live but the VM is not yet fully initialized.
13061       Once this event is generated, the agent is free to call any JNI function.
13062       This event signals the beginning of the start phase,
13063       <jvmti/> functions permitted in the start phase may be called.
13064       <p/>
13065       The timing of this event may depend on whether the agent has added the
13066       <internallink id="jvmtiCapabilities.can_generate_early_vmstart">
13067       <code>can_generate_early_vmstart</code></internallink> capability or not.
13068       If the capability has been added then the VM posts the event as early
13069       as possible. The VM is capable of executing bytecode but it may not have
13070       initialized to the point where it can load classes in modules other than
13071       <code>java.base</code>, or even arbitrary classes in <code>java.base</code>.
13072       Agents that do load-time instrumentation in this
13073       phase must take great care when instrumenting code that potentially
13074       executes in this phase. Extreme care should also be taken with JNI
13075       <code>FindClass</code> as it may not be possible to load classes and attempts
13076       to do so may result in unpredictable behavior, maybe even stability issues
13077       on some VM implementations.
13078       If the capability has not been added then the VM delays posting this
13079       event until it is capable of loading classes in modules other than
13080       <code>java.base</code> or the VM has completed its initialization.
13081       Agents that create more than one JVM TI environment, where the
13082       capability is added to some but not all environments, may observe the
13083       start phase beginning earlier in the JVM TI environments that possess
13084       the capability.
13085       <p/>
13086       In the case of VM start-up failure, this event will not be sent.
13087     </description>
13088     <origin>jvmdi</origin>
13089     <capabilities>
13090     </capabilities>
13091     <parameters>
13092       <param id="jni_env">
13093         <outptr>
13094           <struct>JNIEnv</struct>
13095         </outptr>
13096           <description>
13097             The JNI environment of the event (current) thread.
13098           </description>
13099       </param>
13100     </parameters>
13101   </event>
13102 
13103   <event label="VM Initialization Event"
13104          id="VMInit" const="JVMTI_EVENT_VM_INIT" num="50">
13105     <description>
13106       The VM initialization event signals the completion of VM initialization. Once
13107       this event is generated, the agent is free to call any JNI or <jvmti/>
13108       function. The VM initialization event can be preceded by or can be concurrent
13109       with other events, but
13110       the preceding events should be handled carefully, if at all, because the
13111       VM has not completed its initialization. The thread start event for the
13112       main application thread is guaranteed not to occur until after the
13113       handler for the VM initialization event returns.
13114       <p/>
13115       In the case of VM start-up failure, this event will not be sent.
13116     </description>
13117     <origin>jvmdi</origin>
13118     <capabilities>
13119     </capabilities>
13120     <parameters>
13121       <param id="jni_env">
13122         <outptr>
13123           <struct>JNIEnv</struct>
13124         </outptr>
13125           <description>
13126             The JNI environment of the event (current) thread.
13127           </description>
13128       </param>
13129       <param id="thread">
13130         <jthread/>
13131           <description>
13132             The initial thread
13133           </description>
13134       </param>
13135     </parameters>
13136   </event>
13137 
13138   <event label="VM Death Event"
13139          id="VMDeath" const="JVMTI_EVENT_VM_DEATH" num="51">
13140     <description>
13141       The VM death event notifies the agent of the termination of the VM.
13142       No events will occur after the VMDeath event.
13143       <p/>
13144       In the case of VM start-up failure, this event will not be sent.
13145       Note that <internallink id="onunload">Agent_OnUnload</internallink>
13146       will still be called in these cases.
13147     </description>
13148     <origin>jvmdi</origin>
13149     <capabilities>
13150     </capabilities>
13151     <parameters>
13152       <param id="jni_env">
13153         <outptr>
13154           <struct>JNIEnv</struct>
13155         </outptr>
13156           <description>
13157             The JNI environment of the event (current) thread
13158           </description>
13159       </param>
13160     </parameters>
13161   </event>
13162 
13163   <event label="Compiled Method Load" phase="start"
13164          id="CompiledMethodLoad" const="JVMTI_EVENT_COMPILED_METHOD_LOAD" num="68">
13165     <description>
13166       Sent when a method is compiled and loaded into memory by the VM.
13167       If it is unloaded, the <eventlink id="CompiledMethodUnload"/> event is sent.
13168       If it is moved, the <eventlink id="CompiledMethodUnload"/> event is sent,
13169       followed by a new <code>CompiledMethodLoad</code> event.
13170       Note that a single method may have multiple compiled forms, and that
13171       this event will be sent for each form.
13172       Note also that several methods may be inlined into a single
13173       address range, and that this event will be sent for each method.
13174       <p/>
13175       These events can be sent after their initial occurrence with
13176       <functionlink id="GenerateEvents"></functionlink>.
13177     </description>
13178     <origin>jvmpi</origin>
13179     <typedef id="jvmtiAddrLocationMap" label="Native address to location entry">
13180       <field id="start_address">
13181         <vmbuf><void/></vmbuf>
13182         <description>
13183           Starting native address of code corresponding to a location
13184         </description>
13185       </field>
13186       <field id="location">
13187         <jlocation/>
13188         <description>
13189           Corresponding location. See
13190           <functionlink id="GetJLocationFormat"></functionlink>
13191           for the meaning of location.
13192         </description>
13193       </field>
13194     </typedef>
13195     <capabilities>
13196       <required id="can_generate_compiled_method_load_events"></required>
13197     </capabilities>
13198     <parameters>
13199       <param id="klass">
13200         <jclass method="method"/>
13201           <description>
13202             Class of the method being compiled and loaded
13203           </description>
13204       </param>
13205       <param id="method">
13206         <jmethodID class="klass"/>
13207           <description>
13208             Method being compiled and loaded
13209           </description>
13210       </param>
13211       <param id="code_size">
13212         <jint/>
13213         <description>
13214           Size of compiled code
13215         </description>
13216       </param>
13217       <param id="code_addr">
13218         <vmbuf><void/></vmbuf>
13219         <description>
13220           Address where compiled method code is loaded
13221         </description>
13222       </param>
13223       <param id="map_length">
13224         <jint/>
13225         <description>
13226           Number of <typelink id="jvmtiAddrLocationMap"></typelink>
13227           entries in the address map.
13228           Zero if mapping information cannot be supplied.
13229         </description>
13230       </param>
13231       <param id="map">
13232         <vmbuf><struct>jvmtiAddrLocationMap</struct></vmbuf>
13233         <description>
13234           Map from native addresses to location.
13235           The native address range of each entry is from
13236           <fieldlink id="start_address" struct="jvmtiAddrLocationMap"></fieldlink>
13237           to <code>start_address-1</code> of the next entry.
13238           <code>NULL</code> if mapping information cannot be supplied.
13239         </description>
13240       </param>
13241       <param id="compile_info">
13242         <vmbuf><void/></vmbuf>
13243         <description>
13244           VM-specific compilation information.
13245           The referenced compile information is managed by the VM
13246           and must not depend on the agent for collection.
13247           A VM implementation defines the content and lifetime
13248           of the information.
13249         </description>
13250       </param>
13251     </parameters>
13252   </event>
13253 
13254   <event label="Compiled Method Unload" phase="start"
13255          id="CompiledMethodUnload" const="JVMTI_EVENT_COMPILED_METHOD_UNLOAD" num="69">
13256     <description>
13257       Sent when a compiled method is unloaded from memory.
13258       This event might not be sent on the thread which performed the unload.
13259       This event may be sent sometime after the unload occurs, but
13260       will be sent before the memory is reused
13261       by a newly generated compiled method. This event may be sent after
13262       the class is unloaded.
13263     </description>
13264     <origin>jvmpi</origin>
13265     <capabilities>
13266       <required id="can_generate_compiled_method_load_events"></required>
13267     </capabilities>
13268     <parameters>
13269       <param id="klass">
13270         <jclass method="method"/>
13271           <description>
13272             Class of the compiled method being unloaded.
13273           </description>
13274       </param>
13275       <param id="method">
13276         <jmethodID class="klass"/>
13277           <description>
13278             Compiled method being unloaded.
13279             For identification of the compiled method only -- the class
13280             may be unloaded and therefore the method should not be used
13281             as an argument to further JNI or <jvmti/> functions.
13282           </description>
13283       </param>
13284       <param id="code_addr">
13285         <vmbuf><void/></vmbuf>
13286         <description>
13287           Address where compiled method code was loaded.
13288           For identification of the compiled method only --
13289           the space may have been reclaimed.
13290         </description>
13291       </param>
13292     </parameters>
13293   </event>
13294 
13295   <event label="Dynamic Code Generated" phase="any"
13296          id="DynamicCodeGenerated" const="JVMTI_EVENT_DYNAMIC_CODE_GENERATED" num="70">
13297     <description>
13298       Sent when a component of the virtual machine is generated dynamically.
13299       This does not correspond to Java programming language code that is
13300       compiled--see <eventlink id="CompiledMethodLoad"></eventlink>.
13301       This is for native code--for example, an interpreter that is generated
13302       differently depending on command-line options.
13303       <p/>
13304       Note that this event has no controlling capability.
13305       If a VM cannot generate these events, it simply does not send any.
13306       <p/>
13307       These events can be sent after their initial occurrence with
13308       <functionlink id="GenerateEvents"></functionlink>.
13309     </description>
13310     <origin>jvmpi</origin>
13311     <capabilities>
13312     </capabilities>
13313     <parameters>
13314       <param id="name">
13315         <vmbuf><char/></vmbuf>
13316         <description>
13317           Name of the code, encoded as a
13318           <internallink id="mUTF">modified UTF-8</internallink> string.
13319           Intended for display to an end-user.
13320           The name might not be unique.
13321         </description>
13322       </param>
13323       <param id="address">
13324         <vmbuf><void/></vmbuf>
13325         <description>
13326           Native address of the code
13327         </description>
13328       </param>
13329       <param id="length">
13330         <jint/>
13331         <description>
13332           Length in bytes of the code
13333         </description>
13334       </param>
13335     </parameters>
13336   </event>
13337 
13338   <event label="Data Dump Request"
13339          id="DataDumpRequest" const="JVMTI_EVENT_DATA_DUMP_REQUEST" num="71">
13340     <description>
13341       Sent by the VM to request the agent to dump its data.  This
13342       is just a hint and the agent need not react to this event.
13343       This is useful for processing command-line signals from users.  For
13344       example, in the Java 2 SDK a CTRL-Break on Win32 and a CTRL-\ on Solaris
13345       causes the VM to send this event to the agent.
13346     </description>
13347     <origin>jvmpi</origin>
13348     <capabilities>
13349     </capabilities>
13350     <parameters>
13351     </parameters>
13352   </event>
13353 
13354   <event label="Monitor Contended Enter"
13355          id="MonitorContendedEnter" const="JVMTI_EVENT_MONITOR_CONTENDED_ENTER" filtered="thread" num="75">
13356     <description>
13357       Sent when a thread is attempting to enter a Java programming language
13358       monitor already acquired by another thread.
13359     </description>
13360     <origin>jvmpi</origin>
13361     <capabilities>
13362       <required id="can_generate_monitor_events"></required>
13363     </capabilities>
13364     <parameters>
13365       <param id="jni_env">
13366         <outptr>
13367           <struct>JNIEnv</struct>
13368         </outptr>
13369           <description>
13370             The JNI environment of the event (current) thread
13371           </description>
13372       </param>
13373       <param id="thread">
13374         <jthread/>
13375           <description>
13376             JNI local reference to the thread
13377             attempting to enter the monitor
13378           </description>
13379       </param>
13380       <param id="object">
13381         <jobject/>
13382           <description>
13383             JNI local reference to the monitor
13384           </description>
13385       </param>
13386     </parameters>
13387   </event>
13388 
13389   <event label="Monitor Contended Entered"
13390          id="MonitorContendedEntered" const="JVMTI_EVENT_MONITOR_CONTENDED_ENTERED" filtered="thread" num="76">
13391     <description>
13392       Sent when a thread enters a Java programming language
13393       monitor after waiting for it to be released by another thread.
13394     </description>
13395     <origin>jvmpi</origin>
13396     <capabilities>
13397       <required id="can_generate_monitor_events"></required>
13398     </capabilities>
13399     <parameters>
13400       <param id="jni_env">
13401         <outptr>
13402           <struct>JNIEnv</struct>
13403         </outptr>
13404           <description>
13405             The JNI environment of the event (current) thread
13406           </description>
13407       </param>
13408       <param id="thread">
13409         <jthread/>
13410           <description>
13411             JNI local reference to the thread entering
13412             the monitor
13413           </description>
13414       </param>
13415       <param id="object">
13416         <jobject/>
13417           <description>
13418             JNI local reference to the monitor
13419           </description>
13420       </param>
13421     </parameters>
13422   </event>
13423 
13424   <event label="Monitor Wait"
13425          id="MonitorWait" const="JVMTI_EVENT_MONITOR_WAIT" filtered="thread" num="73">
13426     <description>
13427       Sent when a thread is about to wait on an object.
13428     </description>
13429     <origin>jvmpi</origin>
13430     <capabilities>
13431       <required id="can_generate_monitor_events"></required>
13432     </capabilities>
13433     <parameters>
13434       <param id="jni_env">
13435         <outptr>
13436           <struct>JNIEnv</struct>
13437         </outptr>
13438           <description>
13439             The JNI environment of the event (current) thread
13440           </description>
13441       </param>
13442       <param id="thread">
13443         <jthread/>
13444           <description>
13445             JNI local reference to the thread about to wait
13446           </description>
13447       </param>
13448       <param id="object">
13449         <jobject/>
13450           <description>
13451             JNI local reference to the monitor
13452           </description>
13453       </param>
13454       <param id="timeout">
13455         <jlong/>
13456         <description>
13457           The number of milliseconds the thread will wait
13458         </description>
13459       </param>
13460     </parameters>
13461   </event>
13462 
13463   <event label="Monitor Waited"
13464          id="MonitorWaited" const="JVMTI_EVENT_MONITOR_WAITED" filtered="thread" num="74">
13465     <description>
13466       Sent when a thread finishes waiting on an object.
13467     </description>
13468     <origin>jvmpi</origin>
13469     <capabilities>
13470       <required id="can_generate_monitor_events"></required>
13471     </capabilities>
13472     <parameters>
13473       <param id="jni_env">
13474         <outptr>
13475           <struct>JNIEnv</struct>
13476         </outptr>
13477           <description>
13478             The JNI environment of the event (current) thread
13479           </description>
13480       </param>
13481       <param id="thread">
13482         <jthread/>
13483           <description>
13484             JNI local reference to the thread that was finished waiting
13485           </description>
13486       </param>
13487       <param id="object">
13488         <jobject/>
13489           <description>
13490             JNI local reference to the monitor.
13491           </description>
13492       </param>
13493       <param id="timed_out">
13494         <jboolean/>
13495         <description>
13496           True if the monitor timed out
13497         </description>
13498       </param>
13499     </parameters>
13500   </event>
13501 
13502   <event label="Resource Exhausted"
13503          id="ResourceExhausted" const="JVMTI_EVENT_RESOURCE_EXHAUSTED" num="80"
13504          since="1.1">
13505     <description>
13506       Sent when a VM resource needed by a running application has been exhausted.
13507       Except as required by the optional capabilities, the set of resources
13508       which report exhaustion is implementation dependent.
13509       <p/>
13510       The following bit flags define the properties of the resource exhaustion:
13511       <constants id="jvmtiResourceExhaustionFlags"
13512                  label="Resource Exhaustion Flags"
13513                  kind="bits"
13514                  since="1.1">
13515         <constant id="JVMTI_RESOURCE_EXHAUSTED_OOM_ERROR" num="0x0001">
13516           After this event returns, the VM will throw a
13517           <code>java.lang.OutOfMemoryError</code>.
13518         </constant>
13519         <constant id="JVMTI_RESOURCE_EXHAUSTED_JAVA_HEAP" num="0x0002">
13520           The VM was unable to allocate memory from the <tm>Java</tm>
13521           platform <i>heap</i>.
13522           The <i>heap</i> is the runtime
13523           data area from which memory for all class instances and
13524           arrays are allocated.
13525         </constant>
13526         <constant id="JVMTI_RESOURCE_EXHAUSTED_THREADS" num="0x0004">
13527           The VM was unable to create a thread.
13528         </constant>
13529       </constants>
13530     </description>
13531     <origin>new</origin>
13532     <capabilities>
13533       <capability id="can_generate_resource_exhaustion_heap_events">
13534         Can generate events when the VM is unable to allocate memory from the
13535         <internallink id="JVMTI_RESOURCE_EXHAUSTED_JAVA_HEAP">heap</internallink>.
13536       </capability>
13537       <capability id="can_generate_resource_exhaustion_threads_events">
13538         Can generate events when the VM is unable to
13539         <internallink id="JVMTI_RESOURCE_EXHAUSTED_THREADS">create
13540         a thread</internallink>.
13541       </capability>
13542     </capabilities>
13543     <parameters>
13544       <param id="jni_env">
13545         <outptr>
13546           <struct>JNIEnv</struct>
13547         </outptr>
13548           <description>
13549             The JNI environment of the event (current) thread
13550           </description>
13551       </param>
13552       <param id="flags">
13553         <jint/>
13554         <description>
13555           Flags defining the properties of the of resource exhaustion
13556           as specified by the
13557           <internallink id="jvmtiResourceExhaustionFlags">Resource
13558           Exhaustion Flags</internallink>.
13559           </description>
13560         </param>
13561       <param id="reserved">
13562         <vmbuf><void/></vmbuf>
13563         <description>
13564           Reserved.
13565         </description>
13566       </param>
13567       <param id="description">
13568         <vmbuf><char/></vmbuf>
13569         <description>
13570           Description of the resource exhaustion, encoded as a
13571           <internallink id="mUTF">modified UTF-8</internallink> string.
13572         </description>
13573       </param>
13574     </parameters>
13575   </event>
13576 
13577   <event label="VM Object Allocation"
13578          id="VMObjectAlloc" const="JVMTI_EVENT_VM_OBJECT_ALLOC" num="84">
13579     <description>
13580       Sent when a method causes the virtual machine to directly allocate an
13581       Object visible to Java programming language code.
13582       Generally object allocation should be detected by instrumenting
13583       the bytecodes of allocating methods.
13584       Object allocation generated in native code by JNI function
13585       calls should be detected using
13586       <internallink id="jniIntercept">JNI function interception</internallink>.
13587       Some methods might not have associated bytecodes and are not
13588       native methods, they instead are executed directly by the
13589       VM. These methods should send this event.
13590       Virtual machines which are incapable of bytecode instrumentation
13591       for some or all of their methods can send this event.
13592 
13593       Note that the <internallink
13594       id="SampledObjectAlloc">SampledObjectAlloc</internallink>
13595       event is triggered on all Java object allocations, including those
13596       caused by bytecode method execution, JNI method execution, and
13597       directly by VM methods.
13598       <p/>
13599       Typical examples where this event might be sent:
13600       <ul>
13601         <li>Reflection -- for example, <code>java.lang.Class.newInstance()</code></li>
13602         <li>Methods not represented by bytecodes -- for example, VM intrinsics and
13603             J2ME preloaded classes</li>
13604       </ul>
13605       Cases where this event would not be generated:
13606       <ul>
13607         <li>Allocation due to bytecodes -- for example, the <code>new</code>
13608             and <code>newarray</code> VM instructions</li>
13609         <li>Allocation due to JNI function calls -- for example,
13610             <code>AllocObject</code></li>
13611         <li>Allocations during VM initialization</li>
13612         <li>VM internal objects</li>
13613       </ul>
13614     </description>
13615     <origin>new</origin>
13616     <capabilities>
13617       <required id="can_generate_vm_object_alloc_events"></required>
13618     </capabilities>
13619     <parameters>
13620       <param id="jni_env">
13621         <outptr>
13622           <struct>JNIEnv</struct>
13623         </outptr>
13624           <description>
13625             The JNI environment of the event (current) thread
13626           </description>
13627       </param>
13628       <param id="thread">
13629         <jthread/>
13630           <description>
13631             Thread allocating the object.
13632           </description>
13633       </param>
13634       <param id="object">
13635         <jobject/>
13636           <description>
13637             JNI local reference to the object that was allocated.
13638           </description>
13639       </param>
13640       <param id="object_klass">
13641         <jclass/>
13642           <description>
13643             JNI local reference to the class of the object.
13644           </description>
13645       </param>
13646       <param id="size">
13647         <jlong/>
13648         <description>
13649             Size of the object (in bytes). See <functionlink id="GetObjectSize"/>.
13650         </description>
13651       </param>
13652     </parameters>
13653   </event>
13654 
13655   <event label="Sampled Object Allocation"
13656     id="SampledObjectAlloc" const="JVMTI_EVENT_SAMPLED_OBJECT_ALLOC" filtered="thread" num="86" since="11">
13657     <description>
13658       Sent when an allocated object is sampled.
13659       By default, the sampling interval is set to 512KB. The sampling is semi-random to avoid
13660       pattern-based bias and provides an approximate overall average interval over long periods of
13661       sampling.
13662       <p/>
13663       Each thread tracks how many bytes it has allocated since it sent the last event.
13664       When the number of bytes exceeds the sampling interval, it will send another event.
13665       This implies that, on average, one object will be sampled every time a thread has
13666       allocated 512KB bytes since the last sample.
13667       <p/>
13668       Note that the sampler is pseudo-random: it will not sample every 512KB precisely.
13669       The goal of this is to ensure high quality sampling even if allocation is
13670       happening in a fixed pattern (i.e., the same set of objects are being allocated
13671       every 512KB).
13672       <p/>
13673       If another sampling interval is required, the user can call
13674       <functionlink id="SetHeapSamplingInterval"></functionlink> with a strictly positive integer value,
13675       representing the new sampling interval.
13676       <p/>
13677       This event is sent once the sampled allocation has been performed.  It provides the object, stack trace
13678       of the allocation, the thread allocating, the size of allocation, and the object's class.
13679       <p/>
13680       A typical use case of this system is to determine where heap allocations originate.
13681       In conjunction with weak references and the function
13682       <functionlink id="GetStackTrace"></functionlink>, a user can track which objects were allocated from which
13683       stack trace, and which are still live during the execution of the program.
13684     </description>
13685     <origin>new</origin>
13686     <capabilities>
13687       <required id="can_generate_sampled_object_alloc_events"></required>
13688     </capabilities>
13689     <parameters>
13690       <param id="jni_env">
13691         <outptr>
13692           <struct>JNIEnv</struct>
13693         </outptr>
13694         <description>
13695           The JNI environment of the event (current) thread.
13696         </description>
13697       </param>
13698       <param id="thread">
13699         <jthread/>
13700         <description>
13701           Thread allocating the object.
13702         </description>
13703       </param>
13704       <param id="object">
13705         <jobject/>
13706         <description>
13707           JNI local reference to the object that was allocated.
13708         </description>
13709       </param>
13710       <param id="object_klass">
13711         <jclass/>
13712         <description>
13713           JNI local reference to the class of the object
13714         </description>
13715       </param>
13716       <param id="size">
13717         <jlong/>
13718         <description>
13719           Size of the object (in bytes). See <functionlink id="GetObjectSize"/>.
13720         </description>
13721       </param>
13722     </parameters>
13723   </event>
13724 
13725   <event label="Object Free"
13726         id="ObjectFree" const="JVMTI_EVENT_OBJECT_FREE" num="83">
13727     <description>
13728       An Object Free event is sent when the garbage collector frees an object.
13729       Events are only sent for tagged objects--see
13730       <internallink id="Heap">heap functions</internallink>.
13731       <p/>
13732       The event handler must not use JNI functions and
13733       must not use <jvmti/> functions except those which
13734       specifically allow such use (see the raw monitor, memory management,
13735       and environment local storage functions).
13736     </description>
13737     <origin>new</origin>
13738     <capabilities>
13739       <required id="can_generate_object_free_events"></required>
13740     </capabilities>
13741     <parameters>
13742       <param id="tag">
13743         <jlong/>
13744         <description>
13745           The freed object's tag
13746         </description>
13747       </param>
13748     </parameters>
13749   </event>
13750 
13751   <event label="Garbage Collection Start"
13752          id="GarbageCollectionStart" const="JVMTI_EVENT_GARBAGE_COLLECTION_START" num="81">
13753     <description>
13754       A Garbage Collection Start event is sent when a
13755       garbage collection pause begins.
13756       Only stop-the-world collections are reported--that is, collections during
13757       which all threads cease to modify the state of the Java virtual machine.
13758       This means that some collectors will never generate these events.
13759       This event is sent while the VM is still stopped, thus
13760       the event handler must not use JNI functions and
13761       must not use <jvmti/> functions except those which
13762       specifically allow such use (see the raw monitor, memory management,
13763       and environment local storage functions).
13764       <p/>
13765       This event is always sent as a matched pair with
13766       <eventlink id="GarbageCollectionFinish"/>
13767       (assuming both events are enabled) and no garbage collection
13768       events will occur between them.
13769     </description>
13770     <origin>new</origin>
13771     <capabilities>
13772       <required id="can_generate_garbage_collection_events"></required>
13773     </capabilities>
13774     <parameters>
13775     </parameters>
13776   </event>
13777 
13778   <event label="Garbage Collection Finish"
13779          id="GarbageCollectionFinish" const="JVMTI_EVENT_GARBAGE_COLLECTION_FINISH" num="82">
13780     <description>
13781       A Garbage Collection Finish event is sent when a
13782       garbage collection pause ends.
13783       This event is sent while the VM is still stopped, thus
13784       the event handler must not use JNI functions and
13785       must not use <jvmti/> functions except those which
13786       specifically allow such use (see the raw monitor, memory management,
13787       and environment local storage functions).
13788       <p/>
13789       Some agents may need to do post garbage collection operations that
13790       require the use of the disallowed <jvmti/> or JNI functions. For these
13791       cases an agent thread can be created which waits on a raw monitor,
13792       and the handler for the Garbage Collection Finish event simply
13793       notifies the raw monitor
13794       <p/>
13795       This event is always sent as a matched pair with
13796       <eventlink id="GarbageCollectionStart"/> (assuming both events are enabled).
13797       <issue>
13798         The most important use of this event is to provide timing information,
13799         and thus additional information is not required.  However,
13800         information about the collection which is "free" should be included -
13801         what that information is needs to be determined.
13802       </issue>
13803     </description>
13804     <origin>new</origin>
13805     <capabilities>
13806       <required id="can_generate_garbage_collection_events"></required>
13807     </capabilities>
13808     <parameters>
13809     </parameters>
13810   </event>
13811 
13812   <elide>
13813   <event label="Verbose Output" phase="any"
13814          id="VerboseOutput" const="JVMTI_EVENT_VERBOSE_OUTPUT" num="85">
13815     <description>
13816       Send verbose messages as strings.
13817         <issue>
13818           This format is extremely fragile, as it can change with each
13819           platform, collector and version.  Alternatives include:
13820           <ul>
13821             <li>building off Java programming language M and M APIs</li>
13822             <li>XML</li>
13823             <li>key/value pairs</li>
13824             <li>removing it</li>
13825           </ul>
13826         </issue>
13827         <issue>
13828           Though this seemed trivial to implement.
13829           In the RI it appears this will be quite complex.
13830         </issue>
13831     </description>
13832     <origin>new</origin>
13833     <capabilities>
13834     </capabilities>
13835     <parameters>
13836       <param id="flag">
13837         <enum>jvmtiVerboseFlag</enum>
13838         <description>
13839           Which verbose output is being sent.
13840         </description>
13841       </param>
13842       <param id="message">
13843         <vmbuf><char/></vmbuf>
13844         <description>
13845           Message text, encoded as a
13846           <internallink id="mUTF">modified UTF-8</internallink> string.
13847         </description>
13848       </param>
13849     </parameters>
13850   </event>
13851   </elide>
13852 
13853 </eventsection>
13854 
13855 <datasection>
13856   <intro>
13857     <jvmti/> extends the data types defined by JNI.
13858   </intro>
13859   <basetypes id="jniTypes" label="JNI Types Used in the JVM Tool Interface">
13860     <basetype id="jboolean">
13861       <description>
13862         Holds a Java programming language <code>boolean</code>.
13863         Unsigned 8 bits.
13864       </description>
13865     </basetype>
13866     <basetype id="jchar">
13867       <description>
13868         Holds a Java programming language <code>char</code>.
13869         Unsigned 16 bits.
13870       </description>
13871     </basetype>
13872     <basetype id="jint">
13873       <description>
13874         Holds a Java programming language <code>int</code>.
13875         Signed 32 bits.
13876       </description>
13877     </basetype>
13878     <basetype id="jlong">
13879       <description>
13880         Holds a Java programming language <code>long</code>.
13881         Signed 64 bits.
13882       </description>
13883     </basetype>
13884     <basetype id="jfloat">
13885       <description>
13886         Holds a Java programming language <code>float</code>.
13887         32 bits.
13888       </description>
13889     </basetype>
13890     <basetype id="jdouble">
13891       <description>
13892         Holds a Java programming language <code>double</code>.
13893         64 bits.
13894       </description>
13895     </basetype>
13896     <basetype id="jobject">
13897       <description>
13898         Holds a Java programming language object.
13899       </description>
13900     </basetype>
13901     <basetype id="jclass">
13902       <description>
13903         Holds a Java programming language class.
13904       </description>
13905     </basetype>
13906     <basetype id="jvalue">
13907       <description>
13908         Is a union of all primitive types and <code>jobject</code>.  Thus, holds any Java
13909         programming language value.
13910       </description>
13911     </basetype>
13912     <basetype id="jfieldID">
13913       <description>
13914         Identifies a Java programming language field.
13915         <code>jfieldID</code>s returned by <jvmti/> functions and events may be
13916         safely stored.
13917       </description>
13918     </basetype>
13919     <basetype id="jmethodID">
13920       <description>
13921         Identifies a Java programming language method, initializer, or constructor.
13922         <code>jmethodID</code>s returned by <jvmti/> functions and events may be
13923         safely stored.  However, if the class is unloaded, they become invalid
13924         and must not be used.
13925       </description>
13926     </basetype>
13927     <basetype id="JNIEnv">
13928       <description>
13929         Pointer to the JNI function table.  Pointer to this (<code>JNIEnv *</code>)
13930         is a JNI environment.
13931       </description>
13932     </basetype>
13933   </basetypes>
13934 
13935   <basetypes id="jvmtiTypes" label="JVM Tool Interface Base Types">
13936     <basetype id="jvmtiEnv">
13937       <description>
13938         The <jvmti/> <internallink id="environments">environment</internallink> pointer.
13939         See the <internallink id="FunctionSection">Function Section</internallink>.
13940         <code>jvmtiEnv</code> points to the
13941         <internallink id="FunctionTable">function table</internallink> pointer.
13942       </description>
13943     </basetype>
13944     <basetype id="jthread">
13945       <definition>typedef jobject jthread;</definition>
13946       <description>
13947         Subtype of <datalink id="jobject"></datalink> that holds a thread.
13948       </description>
13949     </basetype>
13950     <basetype id="jthreadGroup">
13951       <definition>typedef jobject jthreadGroup;</definition>
13952       <description>
13953         Subtype of <datalink id="jobject"></datalink> that holds a thread group.
13954       </description>
13955     </basetype>
13956     <basetype id="jlocation">
13957       <definition>typedef jlong jlocation;</definition>
13958       <description>
13959         A 64 bit value, representing a monotonically increasing
13960         executable position within a method.
13961         <code>-1</code> indicates a native method.
13962         See <functionlink id="GetJLocationFormat"></functionlink> for the format on a
13963         given VM.
13964       </description>
13965     </basetype>
13966     <basetype id="jrawMonitorID">
13967       <definition>struct _jrawMonitorID;
13968 typedef struct _jrawMonitorID *jrawMonitorID;</definition>
13969       <description>
13970         A raw monitor.
13971       </description>
13972     </basetype>
13973     <basetype id="jvmtiError">
13974       <description>
13975         Holds an error return code.
13976         See the <internallink id="ErrorSection">Error section</internallink> for possible values.
13977         <example>
13978 typedef enum {
13979     JVMTI_ERROR_NONE = 0,
13980     JVMTI_ERROR_INVALID_THREAD = 10,
13981       ...
13982 } jvmtiError;
13983 </example>
13984       </description>
13985     </basetype>
13986     <basetype id="jvmtiEvent">
13987       <description>
13988         An identifier for an event type.
13989         See the <internallink id="EventSection">Event section</internallink> for possible values.
13990         It is guaranteed that future versions of this specification will
13991         never assign zero as an event type identifier.
13992 <example>
13993 typedef enum {
13994     JVMTI_EVENT_SINGLE_STEP = 1,
13995     JVMTI_EVENT_BREAKPOINT = 2,
13996       ...
13997 } jvmtiEvent;
13998 </example>
13999       </description>
14000     </basetype>
14001     <basetype id="jvmtiEventCallbacks" name="eventCallbacks">
14002       <description>
14003         The callbacks used for events.
14004 <example>
14005 typedef struct {
14006     jvmtiEventVMInit VMInit;
14007     jvmtiEventVMDeath VMDeath;
14008       ...
14009 } jvmtiEventCallbacks;
14010 </example>
14011         See <internallink id="jvmtiEventCallbacks">event callbacks</internallink>
14012         for the complete structure.
14013         <p/>
14014         Where, for example, the VM initialization callback is defined:
14015 <example>
14016 typedef void (JNICALL *jvmtiEventVMInit)
14017     (jvmtiEnv *jvmti_env,
14018      JNIEnv* jni_env,
14019      jthread thread);
14020 </example>
14021         See the individual events for the callback function definition.
14022       </description>
14023     </basetype>
14024     <basetype id="jniNativeInterface">
14025       <definition>typedef struct JNINativeInterface_ jniNativeInterface;</definition>
14026       <description>
14027         Typedef for the JNI function table <code>JNINativeInterface</code>
14028         defined in the
14029         <externallink id="jni/functions.html#interface-function-table">
14030           JNI Specification</externallink>.
14031         The JNI reference implementation defines this with an underscore.
14032       </description>
14033     </basetype>
14034   </basetypes>
14035 
14036 </datasection>
14037 
14038 <issuessection label="Issues">
14039   <intro id="suspendRequired" label="Resolved Issue: Suspend - Required or Automatic">
14040     JVMDI requires that the agent suspend threads before calling
14041     certain sensitive functions.  JVMPI requires garbage collection to be
14042     disabled before calling certain sensitive functions.
14043     It was suggested that rather than have this requirement, that
14044     VM place itself in a suitable state before performing an
14045     operation.  This makes considerable sense since each VM
14046     knows its requirements and can most easily arrange a
14047     safe state.
14048     <p/>
14049     The ability to externally suspend/resume threads will, of
14050     course, remain.  The ability to enable/disable garbage collection will not.
14051     <p/>
14052     This issue is resolved--suspend will not
14053     be required.  The spec has been updated to reflect this.
14054   </intro>
14055 
14056   <intro id="stackSampling" label="Resolved Issue: Call Stack Sampling">
14057     There are a variety of approaches to sampling call stacks.
14058     The biggest bifurcation is between VM controlled and agent
14059     controlled.
14060     <p/>
14061     This issue is resolved--agent controlled
14062     sampling will be the approach.
14063   </intro>
14064 
14065   <intro id="threadRepresentation" label="Resolved Issue: Thread Representation">
14066     JVMDI represents threads as jthread.  JVMPI primarily
14067     uses JNIEnv* to represent threads.
14068     <p/>
14069     The Expert Group has chosen jthread as the representation
14070     for threads in <jvmti/>.
14071     JNIEnv* is sent by
14072     events since it is needed to JNI functions.  JNIEnv, per the
14073     JNI spec, are not supposed to be used outside their thread.
14074   </intro>
14075 
14076   <intro id="design" label="Resolved Issue: Method Representation">
14077     The JNI spec allows an implementation to depend on jclass/jmethodID
14078     pairs, rather than simply a jmethodID, to reference a method.
14079     JVMDI, for consistency, choose the same representation.
14080     JVMPI, however, specifies that a jmethodID alone maps to a
14081     method.  Both of the Sun <tm>J2SE</tm> virtual machines (Classic and <tm>HotSpot</tm>) store
14082     pointers in jmethodIDs, and as a result, a jmethodID is sufficient.
14083     In fact, any JVM implementation that supports JVMPI must have
14084     such a representation.
14085     <jvmti/> will use jmethodID as a unique representation of a method
14086     (no jclass is used).
14087     There should be efficiency gains, particularly in
14088     functionality like stack dumping, to this representation.
14089     <p/>
14090     Note that fields were not used in JVMPI and that the access profile
14091     of fields differs from methods--for implementation efficiency
14092     reasons, a jclass/jfieldID pair will still be needed for field
14093     reference.
14094   </intro>
14095 
14096   <intro id="localReferenceIssue" label="Resolved Issue: Local References">
14097     Functions return local references.
14098   </intro>
14099 
14100   <intro id="frameRep" label="Resolved Issue: Representation of frames">
14101     In JVMDI, a frame ID is used to represent a frame.  Problem with this
14102     is that a VM must track when a frame becomes invalid, a far better
14103     approach, and the one used in <jvmti/>, is to reference frames by depth.
14104   </intro>
14105 
14106   <intro id="requiredCapabilities" label="Issue: Required Capabilities">
14107     Currently, having a required capabilities means that the functionality
14108     is optional.   Capabilities are useful even for required functionality
14109     since they can inform the VM is needed set-up.  Thus, there should be
14110     a set of capabilities that a conformant implementation must provide
14111     (if requested during Agent_OnLoad).
14112   </intro>
14113 
14114   <intro id="taghint" label="Proposal: add tag hint function">
14115     A hint of the percentage of objects that will be tagged would
14116     help the VM pick a good implementation.
14117   </intro>
14118 
14119   <intro id="moreMonitorQueries" label="Request: More Monitor Quires">
14120   How difficult or easy would be to extend the monitor_info category to include
14121     <pre>
14122   - current number of monitors
14123   - enumeration of monitors
14124   - enumeration of threads waiting on a given monitor
14125     </pre>
14126   The reason for my question is the fact that current get_monitor_info support
14127   requires the agent to specify a given thread to get the info which is probably
14128   OK in the profiling/debugging space, while in the monitoring space the agent
14129   could be watching the monitor list and then decide which thread to ask for
14130   the info. You might ask why is this important for monitoring .... I think it
14131   can aid in the detection/prediction of application contention caused by hot-locks.
14132   </intro>
14133 </issuessection>
14134 
14135 <changehistory id="ChangeHistory" update="09/05/07">
14136   <intro>
14137     The <jvmti/> specification is an evolving document with major, minor,
14138     and micro version numbers.
14139     A released version of the specification is uniquely identified
14140     by its major and minor version.
14141     The functions, events, and capabilities in this specification
14142     indicate a "Since" value which is the major and minor version in
14143     which it was introduced.
14144     The version of the specification implemented by the VM can
14145     be retrieved at runtime with the <functionlink id="GetVersionNumber"/>
14146     function.
14147   </intro>
14148   <change date="14 Nov 2002">
14149     Converted to XML document.
14150   </change>
14151   <change date="14 Nov 2002">
14152     Elided heap dump functions (for now) since what was there
14153     was wrong.
14154   </change>
14155   <change date="18 Nov 2002">
14156     Added detail throughout.
14157   </change>
14158   <change date="18 Nov 2002">
14159     Changed JVMTI_THREAD_STATUS_RUNNING to JVMTI_THREAD_STATUS_RUNNABLE.
14160   </change>
14161   <change date="19 Nov 2002">
14162     Added AsyncGetStackTrace.
14163   </change>
14164   <change date="19 Nov 2002">
14165     Added jframeID return to GetStackTrace.
14166   </change>
14167   <change date="19 Nov 2002">
14168     Elided GetCurrentFrame and GetCallingFrame functions (for now) since what was there
14169     since they are redundant with GetStackTrace.
14170   </change>
14171   <change date="19 Nov 2002">
14172     Elided ClearAllBreakpoints since it has always been redundant.
14173   </change>
14174   <change date="19 Nov 2002">
14175     Added GetSystemProperties.
14176   </change>
14177   <change date="19 Nov 2002">
14178     Changed the thread local storage functions to use jthread.
14179   </change>
14180   <change date="20 Nov 2002">
14181     Added GetJLocationFormat.
14182   </change>
14183   <change date="22 Nov 2002">
14184     Added events and introductory text.
14185   </change>
14186   <change date="22 Nov 2002">
14187     Cross reference type and constant definitions.
14188   </change>
14189   <change date="24 Nov 2002">
14190     Added DTD.
14191   </change>
14192   <change date="24 Nov 2002">
14193     Added capabilities function section.
14194   </change>
14195   <change date="29 Nov 2002">
14196     Assign capabilities to each function and event.
14197   </change>
14198   <change date="29 Nov 2002">
14199     Add <internallink id="jniIntercept">JNI interception functions</internallink>.
14200   </change>
14201   <change date="30 Nov 2002">
14202     Auto generate SetEventNotificationMode capabilities.
14203   </change>
14204   <change date="30 Nov 2002">
14205     Add <eventlink id="VMObjectAlloc"></eventlink> event.
14206   </change>
14207   <change date="30 Nov 2002">
14208     Add <eventlink id="DynamicCodeGenerated"></eventlink> event.
14209   </change>
14210   <change date="30 Nov 2002">
14211     Add const to declarations.
14212   </change>
14213   <change date="30 Nov 2002">
14214     Change method exit and frame pop to send on exception.
14215   </change>
14216   <change date="1 Dec 2002">
14217     Add ForceGarbageCollection.
14218   </change>
14219   <change date="2 Dec 2002">
14220     Redo Xrun section; clarify GetStackTrace and add example;
14221     Fix width problems; use "agent" consistently.
14222   </change>
14223   <change date="8 Dec 2002">
14224     Remove previous start-up intro.
14225     Add <internallink id="environments"><jvmti/> Environments</internallink>
14226     section.
14227   </change>
14228   <change date="8 Dec 2002">
14229     Add <functionlink id="DisposeEnvironment"></functionlink>.
14230   </change>
14231   <change date="9 Dec 2002">
14232     Numerous minor updates.
14233   </change>
14234   <change date="15 Dec 2002">
14235     Add heap profiling functions added:
14236     get/set annotation, iterate live objects/heap.
14237     Add heap profiling functions place holder added:
14238     heap roots.
14239     Heap profiling event added: object free.
14240     Heap profiling event redesigned: vm object allocation.
14241     Heap profiling event placeholders added: garbage collection start/finish.
14242     Native method bind event added.
14243   </change>
14244   <change date="19 Dec 2002">
14245     Revamp suspend/resume functions.
14246     Add origin information with jvmdi tag.
14247     Misc fixes.
14248   </change>
14249   <change date="24 Dec 2002">
14250     Add semantics to types.
14251   </change>
14252   <change date="27 Dec 2002">
14253     Add local reference section.
14254     Autogenerate parameter descriptions from types.
14255   </change>
14256   <change date="28 Dec 2002">
14257     Document that RunAgentThread sends threadStart.
14258   </change>
14259   <change date="29 Dec 2002">
14260     Remove redundant local ref and dealloc warning.
14261     Convert GetRawMonitorName to allocated buffer.
14262     Add GenerateEvents.
14263   </change>
14264   <change date="30 Dec 2002">
14265     Make raw monitors a type and rename to "jrawMonitorID".
14266   </change>
14267   <change date="1 Jan 2003">
14268     Include origin information.
14269     Clean-up JVMDI issue references.
14270     Remove Deallocate warnings which are now automatically generated.
14271   </change>
14272   <change date="2 Jan 2003">
14273     Fix representation issues for jthread.
14274   </change>
14275   <change date="3 Jan 2003">
14276     Make capabilities buffered out to 64 bits - and do it automatically.
14277   </change>
14278   <change date="4 Jan 2003">
14279     Make constants which are enumeration into enum types.
14280     Parameters now of enum type.
14281     Clean-up and index type section.
14282     Replace remaining datadef entities with callback.
14283   </change>
14284   <change date="7 Jan 2003">
14285     Correct GenerateEvents description.
14286     More internal semantics work.
14287   </change>
14288   <change date="9 Jan 2003">
14289     Replace previous GetSystemProperties with two functions
14290     which use allocated information instead fixed.
14291     Add SetSystemProperty.
14292     More internal semantics work.
14293   </change>
14294   <change date="12 Jan 2003">
14295     Add varargs to end of SetEventNotificationMode.
14296   </change>
14297   <change date="20 Jan 2003">
14298     Finish fixing spec to reflect that alloc sizes are jlong.
14299   </change>
14300   <change date="22 Jan 2003">
14301     Allow NULL as RunAgentThread arg.
14302   </change>
14303   <change date="22 Jan 2003">
14304     Fixed names to standardized naming convention
14305     Removed AsyncGetStackTrace.
14306   </change>
14307   <change date="29 Jan 2003">
14308     Since we are using jthread, removed GetThread.
14309   </change>
14310   <change date="31 Jan 2003">
14311     Change GetFieldName to allow NULLs like GetMethodName.
14312   </change>
14313   <change date="29 Feb 2003" version="v40">
14314       Rewrite the introductory text, adding sections on
14315       start-up, environments and bytecode instrumentation.
14316       Change the command line arguments per EG discussions.
14317       Add an introduction to the capabilities section.
14318       Add the extension mechanism category and functions.
14319       Mark for deletion, but clarified anyhow, SuspendAllThreads.
14320       Rename IterateOverLiveObjects to IterateOverReachableObjects and
14321       change the text accordingly.
14322       Clarify IterateOverHeap.
14323       Clarify CompiledMethodLoad.
14324       Discuss prerequisite state for Calling Functions.
14325       Clarify SetAllocationHooks.
14326       Added issues ("To be resolved:") through-out.
14327       And so on...
14328   </change>
14329   <change date="6 Mar 2003" version="v41">
14330       Remove struct from the call to GetOwnedMonitorInfo.
14331       Automatically generate most error documentation, remove
14332       (rather broken) hand written error doc.
14333       Better describe capability use (empty initial set).
14334       Add min value to jint params.
14335       Remove the capability can_access_thread_local_storage.
14336       Rename error JVMTI_ERROR_NOT_IMPLEMENTED to JVMTI_ERROR_MUST_POSSESS_CAPABILITY;
14337       same for *NOT_IMPLEMENTED.
14338       Description fixes.
14339   </change>
14340   <change date="8 Mar 2003" version="v42">
14341       Rename GetClassSignature to GetClassName.
14342       Rename IterateOverClassObjects to IterateOverInstancesOfClass.
14343       Remove GetMaxStack (operand stack isn't used in <jvmti/>).
14344       Description fixes: define launch-time, remove native frame pop
14345       from PopFrame, and assorted clarifications.
14346   </change>
14347   <change date="8 Mar 2003" version="v43">
14348       Fix minor editing problem.
14349   </change>
14350   <change date="10 Mar 2003" version="v44">
14351       Add phase information.
14352       Remap (compact) event numbers.
14353   </change>
14354   <change date="11 Mar 2003" version="v45">
14355       More phase information - allow "any".
14356       Elide raw monitor queries and events.
14357       Minor description fixes.
14358   </change>
14359   <change date="12 Mar 2003" version="v46">
14360       Add GetPhase.
14361       Use "phase" through document.
14362       Elide GetRawMonitorName.
14363       Elide GetObjectMonitors.
14364   </change>
14365   <change date="12 Mar 2003" version="v47">
14366       Fixes from link, XML, and spell checking.
14367       Auto-generate the callback structure.
14368   </change>
14369   <change date="13 Mar 2003" version="v48">
14370       One character XML fix.
14371   </change>
14372   <change date="13 Mar 2003" version="v49">
14373       Change function parameter names to be consistent with
14374       event parameters (fooBarBaz becomes foo_bar_baz).
14375   </change>
14376   <change date="14 Mar 2003" version="v50">
14377       Fix broken link.  Fix thread markers.
14378   </change>
14379   <change date="14 Mar 2003" version="v51">
14380       Change constants so they are under 128 to workaround
14381       compiler problems.
14382   </change>
14383   <change date="23 Mar 2003" version="v52">
14384       Overhaul capabilities.  Separate GetStackTrace into
14385       GetStackTrace and GetStackFrames.
14386   </change>
14387   <change date="8 Apr 2003" version="v54">
14388       Use depth instead of jframeID to reference frames.
14389       Remove the now irrelevant GetCurrentFrame, GetCallerFrame and GetStackFrames.
14390       Remove frame arg from events.
14391   </change>
14392   <change date="9 Apr 2003" version="v55">
14393       Remove GetObjectWithAnnotation since tests show bufferred approach more efficient.
14394       Add missing annotation_count to GetObjectsWithAnnotations
14395   </change>
14396   <change date="10 Apr 2003" version="v56">
14397       Remove confusing parenthetical statement in GetObjectsWithAnnotations
14398   </change>
14399   <change date="13 Apr 2003" version="v58">
14400       Replace jclass/jmethodID representation of method with simply jmethodID;
14401       Pass JvmtiEnv* as first arg of every event; remove JNIEnv* where inappropriate.
14402       Replace can_access_frames with can_access_local_variables; remove from purely stack access.
14403       Use can_get_synthetic_attribute; fix description.
14404       Clarify that zero length arrays must be deallocated.
14405       Clarify RelinquishCapabilities.
14406       Generalize JVMTI_ERROR_VM_DEAD to JVMTI_ERROR_WRONG_PHASE.
14407   </change>
14408   <change date="27 Apr 2003" version="v59">
14409       Remove lingering indirect references to OBSOLETE_METHOD_ID.
14410   </change>
14411   <change date="4 May 2003" version="v60">
14412       Allow DestroyRawMonitor during OnLoad.
14413   </change>
14414   <change date="7 May 2003" version="v61">
14415       Added not monitor owner error return to DestroyRawMonitor.
14416   </change>
14417   <change date="13 May 2003" version="v62">
14418       Clarify semantics of raw monitors.
14419       Change flags on <code>GetThreadStatus</code>.
14420       <code>GetClassLoader</code> return NULL for the bootstrap class loader.
14421       Add <code>GetClassName</code> issue.
14422       Define local variable signature.
14423       Disallow zero in annotations array of <code>GetObjectsWithAnnotations</code>.
14424       Remove over specification in <code>GetObjectsWithAnnotations</code>.
14425       Elide <code>SetAllocationHooks</code>.
14426       Elide <code>SuspendAllThreads</code>.
14427   </change>
14428   <change date="14 May 2003" version="v63">
14429       Define the data type <code>jvmtiEventCallbacks</code>.
14430       Zero length allocations return NULL.
14431       Keep SetAllocationHooks in JVMDI, but remove from <jvmti/>.
14432       Add JVMTI_THREAD_STATUS_FLAG_INTERRUPTED.
14433   </change>
14434   <change date="15 May 2003" version="v64">
14435       Better wording, per review.
14436   </change>
14437   <change date="15 May 2003" version="v65">
14438       First Alpha.
14439       Make jmethodID and jfieldID unique, jclass not used.
14440   </change>
14441   <change date="27 May 2003" version="v66">
14442       Fix minor XSLT errors.
14443   </change>
14444   <change date="13 June 2003" version="v67">
14445       Undo making jfieldID unique (jmethodID still is).
14446   </change>
14447   <change date="17 June 2003" version="v68">
14448       Changes per June 11th Expert Group meeting --
14449       Overhaul Heap functionality: single callback,
14450       remove GetHeapRoots, add reachable iterators,
14451       and rename "annotation" to "tag".
14452       NULL thread parameter on most functions is current
14453       thread.
14454       Add timers.
14455       Remove ForceExit.
14456       Add GetEnvironmentLocalStorage.
14457       Add verbose flag and event.
14458       Add AddToBootstrapClassLoaderSearch.
14459       Update ClassFileLoadHook.
14460   </change>
14461   <change date="18 June 2003" version="v69">
14462       Clean up issues sections.
14463       Rename GetClassName back to GetClassSignature and
14464       fix description.
14465       Add generic signature to GetClassSignature,
14466       GetFieldSignature, GetMethodSignature, and
14467       GetLocalVariableTable.
14468       Elide EstimateCostOfCapabilities.
14469       Clarify that the system property functions operate
14470       on the VM view of system properties.
14471       Clarify Agent_OnLoad.
14472       Remove "const" from JNIEnv* in events.
14473       Add metadata accessors.
14474   </change>
14475   <change date="18 June 2003" version="v70">
14476       Add start_depth to GetStackTrace.
14477       Move system properties to a new category.
14478       Add GetObjectSize.
14479       Remove "X" from command line flags.
14480       XML, HTML, and spell check corrections.
14481   </change>
14482   <change date="19 June 2003" version="v71">
14483       Fix JVMTI_HEAP_ROOT_THREAD to be 6.
14484       Make each synopsis match the function name.
14485       Fix unclear wording.
14486   </change>
14487   <change date="26 June 2003" version="v72">
14488       SetThreadLocalStorage and SetEnvironmentLocalStorage should allow value
14489       to be set to NULL.
14490       NotifyFramePop, GetFrameLocationm and all the local variable operations
14491       needed to have their wording about frames fixed.
14492       Grammar and clarity need to be fixed throughout.
14493       Capitalization and puntuation need to be consistent.
14494       Need micro version number and masks for accessing major, minor, and micro.
14495       The error code lists should indicate which must be returned by
14496       an implementation.
14497       The command line properties should be visible in the properties functions.
14498       Disallow popping from the current thread.
14499       Allow implementations to return opaque frame error when they cannot pop.
14500       The NativeMethodBind event should be sent during any phase.
14501       The DynamicCodeGenerated event should be sent during any phase.
14502       The following functions should be allowed to operate before VMInit:
14503         Set/GetEnvironmentLocalStorage
14504         GetMethodDeclaringClass
14505         GetClassSignature
14506         GetClassModifiers
14507         IsInterface
14508         IsArrayClass
14509         GetMethodName
14510         GetMethodModifiers
14511         GetMaxLocals
14512         GetArgumentsSize
14513         GetLineNumberTable
14514         GetMethodLocation
14515         IsMethodNative
14516         IsMethodSynthetic.
14517       Other changes (to XSL):
14518       Argument description should show asterisk after not before pointers.
14519       NotifyFramePop, GetFrameLocationm and all the local variable operations
14520       should hsve the NO_MORE_FRAMES error added.
14521       Not alive threads should have a different error return than invalid thread.
14522   </change>
14523   <change date="7 July 2003" version="v73">
14524       VerboseOutput event was missing message parameter.
14525       Minor fix-ups.
14526   </change>
14527   <change date="14 July 2003" version="v74">
14528       Technical Publications Department corrections.
14529       Allow thread and environment local storage to be set to NULL.
14530   </change>
14531   <change date="23 July 2003" version="v75">
14532       Use new Agent_OnLoad rather than overloaded JVM_OnLoad.
14533       Add JNICALL to callbacks (XSL).
14534       Document JNICALL requirement for both events and callbacks (XSL).
14535       Restrict RedefineClasses to methods and attributes.
14536       Elide the VerboseOutput event.
14537       VMObjectAlloc: restrict when event is sent and remove method parameter.
14538       Finish loose ends from Tech Pubs edit.
14539   </change>
14540   <change date="24 July 2003" version="v76">
14541       Change ClassFileLoadHook event to send the class instead of a boolean of redefine.
14542   </change>
14543   <change date="24 July 2003" version="v77">
14544       XML fixes.
14545       Minor text clarifications and corrections.
14546   </change>
14547   <change date="24 July 2003" version="v78">
14548       Remove GetExceptionHandlerTable and GetThrownExceptions from <jvmti/>.
14549       Clarify that stack frames are JVM Spec frames.
14550       Split can_get_source_info into can_get_source_file_name, can_get_line_numbers,
14551       and can_get_source_debug_extension.
14552       PopFrame cannot have a native calling method.
14553       Removed incorrect statement in GetClassloaderClasses
14554       (see <vmspec chapter="4.4"/>).
14555   </change>
14556   <change date="24 July 2003" version="v79">
14557       XML and text fixes.
14558       Move stack frame description into Stack Frame category.
14559   </change>
14560   <change date="26 July 2003" version="v80">
14561       Allow NULL (means bootstrap loader) for GetClassloaderClasses.
14562       Add new heap reference kinds for references from classes.
14563       Add timer information struct and query functions.
14564       Add AvailableProcessors.
14565       Rename GetOtherThreadCpuTime to GetThreadCpuTime.
14566       Explicitly add JVMTI_ERROR_INVALID_THREAD and JVMTI_ERROR_THREAD_NOT_ALIVE
14567       to SetEventNotification mode.
14568       Add initial thread to the VM_INIT event.
14569       Remove platform assumptions from AddToBootstrapClassLoaderSearch.
14570   </change>
14571   <change date="26 July 2003" version="v81">
14572       Grammar and clarity changes per review.
14573   </change>
14574   <change date="27 July 2003" version="v82">
14575       More grammar and clarity changes per review.
14576       Add Agent_OnUnload.
14577   </change>
14578   <change date="28 July 2003" version="v83">
14579       Change return type of Agent_OnUnload to void.
14580   </change>
14581   <change date="28 July 2003" version="v84">
14582       Rename JVMTI_REFERENCE_ARRAY to JVMTI_REFERENCE_ARRAY_ELEMENT.
14583   </change>
14584   <change date="28 July 2003" version="v85">
14585       Steal java.lang.Runtime.availableProcessors() wording for
14586       AvailableProcessors().
14587       Guarantee that zero will never be an event ID.
14588       Remove some issues which are no longer issues.
14589       Per review, rename and more completely document the timer
14590       information functions.
14591   </change>
14592   <change date="29 July 2003" version="v86">
14593       Non-spec visible change to XML controlled implementation:
14594         SetThreadLocalStorage must run in VM mode.
14595   </change>
14596   <change date="5 August 2003" version="0.1.87">
14597       Add GetErrorName.
14598       Add varargs warning to jvmtiExtensionEvent.
14599       Remove "const" on the jvmtiEnv* of jvmtiExtensionEvent.
14600       Remove unused can_get_exception_info capability.
14601       Pass jvmtiEnv* and JNIEnv* to the jvmtiStartFunction.
14602       Fix jvmtiExtensionFunctionInfo.func declared type.
14603       Extension function returns error code.
14604       Use new version numbering.
14605   </change>
14606   <change date="5 August 2003" version="0.2.88">
14607       Remove the ClassUnload event.
14608   </change>
14609   <change date="8 August 2003" version="0.2.89">
14610       Heap reference iterator callbacks return an enum that
14611       allows outgoing object references to be ignored.
14612       Allow JNIEnv as a param type to extension events/functions.
14613   </change>
14614   <change date="15 August 2003" version="0.2.90">
14615       Fix a typo.
14616   </change>
14617   <change date="2 September 2003" version="0.2.91">
14618       Remove all metadata functions: GetClassMetadata,
14619       GetFieldMetadata, and GetMethodMetadata.
14620   </change>
14621   <change date="1 October 2003" version="0.2.92">
14622       Mark the functions Allocate. Deallocate, RawMonitor*,
14623       SetEnvironmentLocalStorage, and GetEnvironmentLocalStorage
14624       as safe for use in heap callbacks and GC events.
14625   </change>
14626   <change date="24 November 2003" version="0.2.93">
14627       Add pass through opaque user data pointer to heap iterate
14628       functions and callbacks.
14629       In the CompiledMethodUnload event, send the code address.
14630       Add GarbageCollectionOccurred event.
14631       Add constant pool reference kind.
14632       Mark the functions CreateRawMonitor and DestroyRawMonitor
14633       as safe for use in heap callbacks and GC events.
14634       Clarify: VMDeath, GetCurrentThreadCpuTimerInfo,
14635       GetThreadCpuTimerInfo, IterateOverReachableObjects,
14636       IterateOverObjectsReachableFromObject, GetTime and
14637       JVMTI_ERROR_NULL_POINTER.
14638       Add missing errors to: GenerateEvents and
14639       AddToBootstrapClassLoaderSearch.
14640       Fix description of ClassFileLoadHook name parameter.
14641       In heap callbacks and GC/ObjectFree events, specify
14642       that only explicitly allowed functions can be called.
14643       Allow GetCurrentThreadCpuTimerInfo, GetCurrentThreadCpuTime,
14644       GetTimerInfo, and GetTime during callback.
14645       Allow calling SetTag/GetTag during the onload phase.
14646       SetEventNotificationMode, add: error attempted inappropriate
14647       thread level control.
14648       Remove jvmtiExceptionHandlerEntry.
14649       Fix handling of native methods on the stack --
14650       location_ptr param of GetFrameLocation, remove
14651       JVMTI_ERROR_OPAQUE_FRAME from GetFrameLocation,
14652       jvmtiFrameInfo.location, and jlocation.
14653       Remove typo (from JVMPI) implying that the MonitorWaited
14654       event is sent on sleep.
14655   </change>
14656   <change date="25 November 2003" version="0.2.94">
14657       Clarifications and typos.
14658   </change>
14659   <change date="3 December 2003" version="0.2.95">
14660       Allow NULL user_data in heap iterators.
14661   </change>
14662   <change date="28 January 2004" version="0.2.97">
14663       Add GetThreadState, deprecate GetThreadStatus.
14664   </change>
14665   <change date="29 January 2004" version="0.2.98">
14666       INVALID_SLOT and TYPE_MISMATCH errors should be optional.
14667   </change>
14668   <change date="12 February 2004" version="0.2.102">
14669       Remove MonitorContendedExit.
14670       Added JNIEnv parameter to VMObjectAlloc.
14671       Clarified definition of class_tag and referrer_index
14672       parameters to heap callbacks.
14673   </change>
14674   <change date="16 Febuary 2004" version="0.2.103">
14675       Document JAVA_TOOL_OPTIONS.
14676   </change>
14677   <change date="17 Febuary 2004" version="0.2.105">
14678       Divide start phase into primordial and start.
14679       Add VMStart event
14680       Change phase associations of functions and events.
14681   </change>
14682   <change date="18 Febuary 2004" version="0.3.6">
14683       Elide deprecated GetThreadStatus.
14684       Bump minor version, subtract 100 from micro version
14685   </change>
14686   <change date="18 Febuary 2004" version="0.3.7">
14687       Document that timer nanosecond values are unsigned.
14688       Clarify text having to do with native methods.
14689   </change>
14690   <change date="19 Febuary 2004" version="0.3.8">
14691       Fix typos.
14692       Remove elided deprecated GetThreadStatus.
14693   </change>
14694   <change date="23 Febuary 2004" version="0.3.9">
14695       Require NotifyFramePop to act on suspended threads.
14696   </change>
14697   <change date="24 Febuary 2004" version="0.3.10">
14698       Add capabilities
14699         (<internallink id="jvmtiCapabilities.can_redefine_any_class"
14700          ><code>can_redefine_any_class</code></internallink>
14701       and
14702          <internallink id="jvmtiCapabilities.can_generate_all_class_hook_events"
14703          ><code>can_generate_all_class_hook_events</code></internallink>)
14704       and an error (<errorlink id="JVMTI_ERROR_UNMODIFIABLE_CLASS"></errorlink>)
14705       which allow some classes to be unmodifiable.
14706   </change>
14707   <change date="28 Febuary 2004" version="0.3.11">
14708       Add JVMTI_ERROR_MUST_POSSESS_CAPABILITY to SetEventNotificationMode.
14709   </change>
14710   <change date="8 March 2004" version="0.3.12">
14711       Clarified CompiledMethodUnload so that it is clear the event
14712       may be posted after the class has been unloaded.
14713   </change>
14714   <change date="5 March 2004" version="0.3.13">
14715       Change the size parameter of VMObjectAlloc to jlong to match GetObjectSize.
14716   </change>
14717   <change date="13 March 2004" version="0.3.14">
14718       Added guideline for the use of the JNI FindClass function in event
14719       callback functions.
14720   </change>
14721   <change date="15 March 2004" version="0.3.15">
14722       Add GetAllStackTraces and GetThreadListStackTraces.
14723   </change>
14724   <change date="19 March 2004" version="0.3.16">
14725       ClassLoad and ClassPrepare events can be posted during start phase.
14726   </change>
14727   <change date="25 March 2004" version="0.3.17">
14728       Add JVMTI_ERROR_NATIVE_METHOD to GetLineNumberTable, GetLocalVariableTable,
14729       GetMaxLocals, GetArgumentsSize, GetMethodLocation, GetBytecodes.
14730   </change>
14731   <change date="29 March 2004" version="0.3.18">
14732       Return the timer kind in the timer information structure.
14733   </change>
14734   <change date="31 March 2004" version="0.3.19">
14735       Spec clarifications:
14736       JVMTI_THREAD_STATE_IN_NATIVE might not include JNI or <jvmti/>.
14737       ForceGarbageCollection does not run finalizers.
14738       The context of the specification is the Java platform.
14739       Warn about early instrumentation.
14740   </change>
14741   <change date="1 April 2004" version="0.3.20">
14742       Refinements to the above clarifications and
14743       Clarify that an error returned by Agent_OnLoad terminates the VM.
14744   </change>
14745   <change date="1 April 2004" version="0.3.21">
14746       Array class creation does not generate a class load event.
14747   </change>
14748   <change date="7 April 2004" version="0.3.22">
14749       Align thread state hierarchy more closely with java.lang.Thread.State.
14750   </change>
14751   <change date="12 April 2004" version="0.3.23">
14752       Clarify the documentation of thread state.
14753   </change>
14754   <change date="19 April 2004" version="0.3.24">
14755       Remove GarbageCollectionOccurred event -- can be done by agent.
14756   </change>
14757   <change date="22 April 2004" version="0.3.25">
14758       Define "command-line option".
14759   </change>
14760   <change date="29 April 2004" version="0.3.26">
14761       Describe the intended use of bytecode instrumentation.
14762       Fix description of extension event first parameter.
14763   </change>
14764   <change date="30 April 2004" version="0.3.27">
14765       Clarification and typos.
14766   </change>
14767   <change date="18 May 2004" version="0.3.28">
14768       Remove DataDumpRequest event.
14769   </change>
14770   <change date="18 May 2004" version="0.3.29">
14771       Clarify RawMonitorWait with zero timeout.
14772       Clarify thread state after RunAgentThread.
14773   </change>
14774   <change date="24 May 2004" version="0.3.30">
14775       Clean-up: fix bad/old links, etc.
14776   </change>
14777   <change date="30 May 2004" version="0.3.31">
14778       Clarifications including:
14779       All character strings are modified UTF-8.
14780       Agent thread visibiity.
14781       Meaning of obsolete method version.
14782       Thread invoking heap callbacks,
14783   </change>
14784   <change date="1 June 2004" version="1.0.32">
14785       Bump major.minor version numbers to "1.0".
14786   </change>
14787   <change date="2 June 2004" version="1.0.33">
14788       Clarify interaction between ForceGarbageCollection
14789       and ObjectFree.
14790   </change>
14791   <change date="6 June 2004" version="1.0.34">
14792       Restrict AddToBootstrapClassLoaderSearch and
14793       SetSystemProperty to the OnLoad phase only.
14794   </change>
14795   <change date="11 June 2004" version="1.0.35">
14796       Fix typo in SetTag.
14797   </change>
14798   <change date="18 June 2004" version="1.0.36">
14799       Fix trademarks.
14800       Add missing parameter in example GetThreadState usage.
14801   </change>
14802   <change date="4 August 2004" version="1.0.37">
14803       Copyright updates.
14804   </change>
14805   <change date="5 November 2004" version="1.0.38">
14806       Add missing function table layout.
14807       Add missing description of C++ member function format of functions.
14808       Clarify that name in CFLH can be NULL.
14809       Released as part of <tm>J2SE</tm> 5.0.
14810   </change>
14811   <change date="24 April 2005" version="1.1.47">
14812       Bump major.minor version numbers to "1.1".
14813       Add ForceEarlyReturn* functions.
14814       Add GetOwnedMonitorStackDepthInfo function.
14815       Add GetCurrentThread function.
14816       Add "since" version marker.
14817       Add AddToSystemClassLoaderSearch.
14818       Allow AddToBootstrapClassLoaderSearch be used in live phase.
14819       Fix historic rubbish in the descriptions of the heap_object_callback
14820       parameter of IterateOverHeap and IterateOverInstancesOfClass functions;
14821       disallow NULL for this parameter.
14822       Clarify, correct and make consistent: wording about current thread,
14823       opaque frames and insufficient number of frames in PopFrame.
14824       Consistently use "current frame" rather than "topmost".
14825       Clarify the JVMTI_ERROR_TYPE_MISMATCH errors in GetLocal* and SetLocal*
14826       by making them compatible with those in ForceEarlyReturn*.
14827       Many other clarifications and wording clean ups.
14828   </change>
14829   <change date="25 April 2005" version="1.1.48">
14830       Add GetConstantPool.
14831       Switch references to the first edition of the VM Spec, to the seconds edition.
14832   </change>
14833   <change date="26 April 2005" version="1.1.49">
14834       Clarify minor/major version order in GetConstantPool.
14835   </change>
14836   <change date="26 April 2005" version="1.1.50">
14837       Add SetNativeMethodPrefix and SetNativeMethodPrefixes.
14838       Reassign GetOwnedMonitorStackDepthInfo to position 153.
14839       Break out Class Loader Search in its own documentation category.
14840       Deal with overly long lines in XML source.
14841   </change>
14842   <change date="29 April 2005" version="1.1.51">
14843       Allow agents be started in the live phase.
14844       Added paragraph about deploying agents.
14845   </change>
14846   <change date="30 April 2005" version="1.1.52">
14847       Add specification description to SetNativeMethodPrefix(es).
14848       Better define the conditions on GetConstantPool.
14849   </change>
14850   <change date="30 April 2005" version="1.1.53">
14851       Break out the GetClassVersionNumber function from GetConstantPool.
14852       Clean-up the references to the VM Spec.
14853   </change>
14854   <change date="1 May 2005" version="1.1.54">
14855       Allow SetNativeMethodPrefix(es) in any phase.
14856       Add clarifications about the impact of redefinition on GetConstantPool.
14857   </change>
14858   <change date="2 May 2005" version="1.1.56">
14859       Various clarifications to SetNativeMethodPrefix(es).
14860   </change>
14861   <change date="2 May 2005" version="1.1.57">
14862       Add missing performance warning to the method entry event.
14863   </change>
14864   <change date="5 May 2005" version="1.1.58">
14865       Remove internal JVMDI support.
14866   </change>
14867   <change date="8 May 2005" version="1.1.59">
14868       Add <functionlink id="RetransformClasses"/>.
14869       Revamp the bytecode instrumentation documentation.
14870       Change <functionlink id="IsMethodObsolete"/> to no longer
14871       require the can_redefine_classes capability.
14872   </change>
14873   <change date="11 May 2005" version="1.1.63">
14874       Clarifications for retransformation.
14875   </change>
14876   <change date="11 May 2005" version="1.1.64">
14877       Clarifications for retransformation, per review.
14878       Lock "retransformation (in)capable" at class load enable time.
14879   </change>
14880   <change date="4 June 2005" version="1.1.67">
14881       Add new heap functionity which supports reporting primitive values,
14882       allows setting the referrer tag, and has more powerful filtering:
14883       FollowReferences, IterateThroughHeap, and their associated
14884       callbacks, structs, enums, and constants.
14885   </change>
14886   <change date="4 June 2005" version="1.1.68">
14887       Clarification.
14888   </change>
14889   <change date="6 June 2005" version="1.1.69">
14890       FollowReferences, IterateThroughHeap: Put callbacks in a struct;
14891       Add missing error codes; reduce bits in the visit control flags.
14892   </change>
14893   <change date="14 June 2005" version="1.1.70">
14894       More on new heap functionity: spec clean-up per review.
14895   </change>
14896   <change date="15 June 2005" version="1.1.71">
14897       More on new heap functionity: Rename old heap section to Heap (1.0).
14898   </change>
14899   <change date="21 June 2005" version="1.1.72">
14900       Fix typos.
14901   </change>
14902   <change date="27 June 2005" version="1.1.73">
14903       Make referrer info structure a union.
14904   </change>
14905   <change date="9 September 2005" version="1.1.74">
14906       In new heap functions:
14907       Add missing superclass reference kind.
14908       Use a single scheme for computing field indexes.
14909       Remove outdated references to struct based referrer info.
14910   </change>
14911   <change date="12 September 2005" version="1.1.75">
14912       Don't callback during FollowReferences on frivolous java.lang.Object superclass.
14913   </change>
14914   <change date="13 September 2005" version="1.1.76">
14915       In string primitive callback, length now Unicode length.
14916       In array and string primitive callbacks, value now "const".
14917       Note possible compiler impacts on setting JNI function table.
14918   </change>
14919   <change date="13 September 2005" version="1.1.77">
14920       GetClassVersionNumbers() and GetConstantPool() should return
14921       error on array or primitive class.
14922   </change>
14923   <change date="14 September 2005" version="1.1.78">
14924       Grammar fixes.
14925   </change>
14926   <change date="26 September 2005" version="1.1.79">
14927       Add IsModifiableClass query.
14928   </change>
14929   <change date="9 February 2006" version="1.1.81">
14930       Add referrer_class_tag parameter to jvmtiHeapReferenceCallback.
14931   </change>
14932   <change date="13 February 2006" version="1.1.82">
14933       Doc fixes: update can_redefine_any_class to include retransform.
14934       Clarify that exception events cover all Throwables.
14935       In GetStackTrace, no test is done for start_depth too big if start_depth is zero,
14936       Clarify fields reported in Primitive Field Callback -- static vs instance.
14937       Repair confusing names of heap types, including callback names.
14938       Require consistent usage of stack depth in the face of thread launch methods.
14939       Note incompatibility of <jvmti/> memory management with other systems.
14940   </change>
14941   <change date="14 February 2006" version="1.1.85">
14942       Fix typos and missing renames.
14943   </change>
14944   <change date="13 March 2006" version="1.1.86">
14945       Clarify that jmethodIDs and jfieldIDs can be saved.
14946       Clarify that Iterate Over Instances Of Class includes subclasses.
14947   </change>
14948   <change date="14 March 2006" version="1.1.87">
14949       Better phrasing.
14950   </change>
14951   <change date="16 March 2006" version="1.1.88">
14952       Match the referrer_index for static fields in Object Reference Callback
14953       with the Reference Implementation (and all other known implementations);
14954       that is, make it match the definition for instance fields.
14955       In GetThreadListStackTraces, add JVMTI_ERROR_INVALID_THREAD to cover
14956       an invalid thread in the list; and specify that not started threads
14957       return empty stacks.
14958   </change>
14959   <change date="17 March 2006" version="1.1.89">
14960       Typo.
14961   </change>
14962   <change date="25 March 2006" version="1.1.90">
14963       Typo.
14964   </change>
14965   <change date="6 April 2006" version="1.1.91">
14966       Remove restrictions on AddToBootstrapClassLoaderSearch and
14967       AddToSystemClassLoaderSearch.
14968   </change>
14969   <change date="1 May 2006" version="1.1.93">
14970       Changed spec to return -1 for monitor stack depth for the
14971       implementation which can not determine stack depth.
14972   </change>
14973   <change date="3 May 2006" version="1.1.94">
14974       Corrections for readability and accuracy courtesy of Alan Pratt of IBM.
14975       List the object relationships reported in FollowReferences.
14976   </change>
14977   <change date="5 May 2006" version="1.1.95">
14978       Clarify the object relationships reported in FollowReferences.
14979   </change>
14980   <change date="28 June 2006" version="1.1.98">
14981       Clarify DisposeEnvironment; add warning.
14982       Fix typos in SetLocalXXX "retrieve" => "set".
14983       Clarify that native method prefixes must remain set while used.
14984       Clarify that exactly one Agent_OnXXX is called per agent.
14985       Clarify that library loading is independent from start-up.
14986       Remove ambiguous reference to Agent_OnLoad in the Agent_OnUnload spec.
14987   </change>
14988   <change date="31 July 2006" version="1.1.99">
14989       Clarify the interaction between functions and exceptions.
14990       Clarify and give examples of field indices.
14991       Remove confusing "That is" sentence from MonitorWait and MonitorWaited events.
14992       Update links to point to Java 6.
14993   </change>
14994   <change date="6 August 2006" version="1.1.102">
14995       Add ResourceExhaustedEvent.
14996   </change>
14997   <change date="11 October 2012" version="1.2.2">
14998       Fixed the "HTTP" and "Missing Anchor" errors reported by the LinkCheck tool.
14999   </change>
15000   <change date="19 June 2013" version="1.2.3">
15001       Added support for statically linked agents.
15002   </change>
15003   <change date="13 October 2016" version="9.0.0">
15004       Support for modules:
15005        - The majorversion is 9 now
15006        - The ClassFileLoadHook events are not sent during the primordial phase anymore.
15007        - Allow CompiledMethodLoad events at start phase
15008        - Add new capabilities:
15009           - can_generate_early_vmstart
15010           - can_generate_early_class_hook_events
15011        - Add new functions:
15012           - GetAllModules
15013           - AddModuleReads, AddModuleExports, AddModuleOpens, AddModuleUses, AddModuleProvides
15014           - IsModifiableModule
15015       Clarified can_redefine_any_classes, can_retransform_any_classes and IsModifiableClass API to
15016       disallow some implementation defined classes.
15017   </change>
15018   <change date="12 February 2017" version="9.0.0">
15019       Minor update for GetCurrentThread function:
15020        - The function may return NULL in the start phase if the
15021          can_generate_early_vmstart capability is enabled.
15022   </change>
15023   <change date="7 February 2018" version="11.0.0">
15024       Minor update for new class file NestHost and NestMembers attributes:
15025         - Specify that RedefineClasses and RetransformClasses are not allowed
15026           to change the class file NestHost and NestMembers attributes.
15027         - Add new error JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED
15028           that can be returned by RedefineClasses and RetransformClasses.
15029   </change>
15030   <change date="20 May 2019" version="13.0.0">
15031       Minor spec update for the capability "can_redefine_any_class".
15032       It now says:
15033        "RedefineClasses can be called on any modifiable class. See IsModifiableClass.
15034        (can_redefine_classes must also be set)"
15035   </change>
15036   <change date="5 June 2019" version="13.0.0">
15037       Minor PopFrame spec update:
15038         - The specified thread must be suspended or must be the current thread.
15039           (It was not allowed to be the current thread before.)
15040   </change>
15041   <change date="10 October 2019" version="14.0.0">
15042       Minor update for new class file Record attribute:
15043         - Specify that RedefineClasses and RetransformClasses are not allowed
15044           to change the class file Record attribute.
15045   </change>
15046 </changehistory>
15047 
15048 </specification>
15049 <!-- Keep this comment at the end of the file
15050 Local variables:
15051 mode: sgml
15052 sgml-omittag:t
15053 sgml-shorttag:t
15054 sgml-namecase-general:t
15055 sgml-general-insert-case:lower
15056 sgml-minimize-attributes:nil
15057 sgml-always-quote-attributes:t
15058 sgml-indent-step:2
15059 sgml-indent-data:t
15060 sgml-parent-document:nil
15061 sgml-exposed-tags:nil
15062 sgml-local-catalogs:nil
15063 sgml-local-ecat-files:nil
15064 End:
15065 -->