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25
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358 ]>
359
360 <specification label="JVM(TM) Tool Interface"
361 majorversion="11"
362 minorversion="0"
363 microversion="0">
364 <title subtitle="Version">
365 <tm>JVM</tm> Tool Interface
366 </title>
367
368 <intro id="whatIs" label="What is the JVM Tool Interface?">
369 The <tm>JVM</tm> Tool Interface (<jvmti/>)
370 is a programming interface used by development and monitoring tools.
371 It provides both a way to inspect the state and
372 to control the execution of applications running in the
373 <tm>Java</tm> virtual machine (VM).
374 <p/>
375 <jvmti/> is intended to provide a VM interface for the full breadth of tools
376 that need access to VM state, including but not limited to: profiling,
377 debugging, monitoring, thread analysis, and coverage analysis tools.
378 <p/>
379 <jvmti/> may not be available in all implementations of the <tm>Java</tm> virtual
380 machine.
381 <p/>
382 <jvmti/> is a two-way interface.
383 A client of <jvmti/>, hereafter called an <i>agent</i>,
384 can be notified of
385 interesting occurrences through <internallink id="EventSection">events</internallink>.
386 <jvmti/>
387 can query and control the application through many
388 <internallink id="FunctionSection">functions</internallink>,
389 either in response to events or
390 independent of them.
391 <p/>
392 Agents run in the same process with and communicate directly with
393 the virtual machine executing
394 the application being examined. This communication is
395 through a native interface (<jvmti/>). The native in-process interface allows
396 maximal control with minimal intrusion on the part of a tool.
397 Typically, agents are relatively compact. They can be controlled
398 by a separate process which implements the bulk of a tool's
399 function without interfering with the target application's normal execution.
400 </intro>
401
402 <intro id="architecture" label="Architecture">
403 Tools can be written directly to <jvmti/> or indirectly
404 through higher level interfaces.
405 The Java Platform Debugger Architecture includes <jvmti/>, but also
406 contains higher-level, out-of-process debugger interfaces. The higher-level
407 interfaces are more appropriate than <jvmti/> for many tools.
408 For more information on the Java Platform Debugger Architecture,
409 see the
410 <externallink id="jpda/architecture.html">Java
411 Platform Debugger Architecture website</externallink>.
412 </intro>
413
414 <intro id="writingAgents" label="Writing Agents">
415 Agents can be written in any native language that supports C
416 language calling conventions and C or C++
417 definitions.
418 <p/>
419 The function, event, data type, and constant definitions needed for
420 using <jvmti/> are defined in the include file <code>jvmti.h</code>.
421 To use these definitions add the <tm>J2SE</tm> include directory
422 to your include path and add
423 <example>
424 #include <jvmti.h>
425 </example>
426 to your source code.
427 </intro>
428
429 <intro id="deployingAgents" label="Deploying Agents">
430 An agent is deployed in a platform specific manner but is typically the
431 platform equivalent of a dynamic library. On the <tm>Windows</tm> operating
432 system, for example, an agent library is a "Dynamic Linked Library" (DLL).
433 On the <tm>Solaris</tm> Operating Environment, an agent library is a shared
434 object (<code>.so</code> file).
435 <p/>
436
437 An agent may be started at VM startup by specifying the agent library
438 name using a <internallink id="starting">command line option</internallink>.
439 Some implementations may support a mechanism to <internallink id="onattach">
440 start agents</internallink> in the live <functionlink id="GetPhase">phase</functionlink>.
441 The details of how this is initiated are implementation specific.
442 </intro>
443
444 <intro id="entryPoint" label="Statically Linked Agents (since version 1.2.3)">
445
446 A native JVMTI Agent may be <i>statically linked</i> with the VM.
447 The manner in which the library and VM image are combined is
448 implementation-dependent.
449 An agent L whose image has been combined with the VM is defined as
450 <i>statically linked</i> if and only if the agent exports a function
451 called Agent_OnLoad_L.
452 <p/>
453 If a <i>statically linked</i> agent L exports a function called
454 Agent_OnLoad_L and a function called Agent_OnLoad, the Agent_OnLoad
455 function will be ignored.
456 If an agent L is <i>statically linked</i>, an Agent_OnLoad_L
457 function will be invoked with the same arguments and expected return
458 value as specified for the Agent_OnLoad function.
459 An agent L that is <i>statically linked</i> will prohibit an agent of
460 the same name from being loaded dynamically.
461 <p/>
462 The VM will invoke the Agent_OnUnload_L function of the agent, if such
463 a function is exported, at the same point during VM execution as it would
464 have called the dynamic entry point Agent_OnUnLoad. A statically loaded
465 agent cannot be unloaded. The Agent_OnUnload_L function will still be
466 called to do any other agent shutdown related tasks.
467 If a <i>statically linked</i> agent L exports a function called
468 Agent_OnUnLoad_L and a function called Agent_OnUnLoad, the Agent_OnUnLoad
469 function will be ignored.
470 <p/>
471 If an agent L is <i>statically linked</i>, an Agent_OnAttach_L function
472 will be invoked with the same arguments and expected return value as
473 specified for the Agent_OnAttach function.
474 If a <i>statically linked</i> agent L exports a function called
475 Agent_OnAttach_L and a function called Agent_OnAttach, the Agent_OnAttach
476 function will be ignored.
477 </intro>
478
479 <intro id="starting" label="Agent Command Line Options">
480 The term "command-line option" is used below to
481 mean options supplied in the <code>JavaVMInitArgs</code> argument
482 to the <code>JNI_CreateJavaVM</code> function of the JNI
483 Invocation API.
484 <p/>
485 One of the two following
486 command-line options is used on VM startup to
487 properly load and run agents.
488 These arguments identify the library containing
489 the agent as well as an options
490 string to be passed in at startup.
491 <dl>
492 <dt><code>-agentlib:</code><i><agent-lib-name></i><code>=</code><i><options></i></dt>
493 <dd>
494 The name following <code>-agentlib:</code> is the name of the
495 library to load. Lookup of the library, both its full name and location,
496 proceeds in a platform-specific manner.
497 Typically, the <i><agent-lib-name></i> is expanded to an
498 operating system specific file name.
499 The <i><options></i> will be passed to the agent on start-up.
500 For example, if the option
501 <code>-agentlib:foo=opt1,opt2</code> is specified, the VM will attempt to
502 load the shared library <code>foo.dll</code> from the system <code>PATH</code>
503 under <tm>Windows</tm> or <code>libfoo.so</code> from the
504 <code>LD_LIBRARY_PATH</code> under the <tm>Solaris</tm> operating
505 environment.
506 If the agent library is statically linked into the executable
507 then no actual loading takes place.
508 <p/>
509 </dd>
510 <dt><code>-agentpath:</code><i><path-to-agent></i><code>=</code><i><options></i></dt>
511 <dd>
512 The path following <code>-agentpath:</code> is the absolute path from which
513 to load the library.
514 No library name expansion will occur.
515 The <i><options></i> will be passed to the agent on start-up.
516 For example, if the option
517 <code>-agentpath:c:\myLibs\foo.dll=opt1,opt2</code> is specified, the VM will attempt to
518 load the shared library <code>c:\myLibs\foo.dll</code>. If the agent
519 library is statically linked into the executable
520 then no actual loading takes place.
521 <p/>
522 </dd>
523 </dl>
524 For a dynamic shared library agent, the start-up routine
525 <internallink id="onload"><code>Agent_OnLoad</code></internallink>
526 in the library will be invoked. If the agent library is statically linked
527 into the executable then the system will attempt to invoke the
528 <code>Agent_OnLoad_<agent-lib-name></code> entry point where
529 <agent-lib-name> is the basename of the
530 agent. In the above example <code>-agentpath:c:\myLibs\foo.dll=opt1,opt2</code>,
531 the system will attempt to find and call the <code>Agent_OnLoad_foo</code> start-up routine.
532 <p/>
533 Libraries loaded with <code>-agentlib:</code> or <code>-agentpath:</code>
534 will be searched for JNI native method implementations to facilitate the
535 use of Java programming language code in tools, as is needed for
536 <internallink id="bci">bytecode instrumentation</internallink>.
537 <p/>
538 The agent libraries will be searched after all other libraries have been
539 searched (agents wishing to override or intercept the native method
540 implementations of non-agent methods can use the
541 <eventlink id="NativeMethodBind">NativeMethodBind event</eventlink>).
542 <p/>
543 These switches do the above and nothing more - they do not change the
544 state of the VM or <jvmti/>. No command line options are needed
545 to enable <jvmti/>
546 or aspects of <jvmti/>, this is handled programmatically
547 by the use of
548 <internallink id="capability">capabilities</internallink>.
549 </intro>
550
551 <intro id="startup" label="Agent Start-Up">
552 The VM starts each agent by invoking a start-up function.
553 If the agent is started in the <code>OnLoad</code>
554 <functionlink id="GetPhase">phase</functionlink> the function
555 <internallink id="onload"><code>Agent_OnLoad</code></internallink>
556 or <internallink id="onload"><code>Agent_OnLoad_L</code></internallink>
557 for statically linked agents will be invoked.
558 If the agent is started in the live
559 <functionlink id="GetPhase">phase</functionlink> the function
560 <internallink id="onattach"><code>Agent_OnAttach</code></internallink>
561 or <internallink id="onattach"><code>Agent_OnAttach_L</code></internallink>
562 for statically linked agents will be invoked.
563 Exactly one call to a start-up function is made per agent.
564 </intro>
565
566 <intro id="onload" label="Agent Start-Up (OnLoad phase)">
567 If an agent is started during the <code>OnLoad</code> phase then its
568 agent library must export a start-up function with the following prototype:
569 <example>
570 JNIEXPORT jint JNICALL
571 Agent_OnLoad(JavaVM *vm, char *options, void *reserved)</example>
572 Or for a statically linked agent named 'L':
573 <example>
574 JNIEXPORT jint JNICALL
575 Agent_OnLoad_L(JavaVM *vm, char *options, void *reserved)</example>
576
577 The VM will start the agent by calling this function.
578 It will be called early enough in VM initialization that:
579 <ul>
580 <li><functionlink id="SetSystemProperty">system properties</functionlink>
581 may be set before they have been used in the start-up of the VM</li>
582 <li>the full set of
583 <internallink id="capability">capabilities</internallink>
584 is still available (note that capabilities that configure the VM
585 may only be available at this time--see the
586 <internallink id="capability">Capability function section</internallink>)</li>
587 <li>no bytecodes have executed</li>
588 <li>no classes have been loaded</li>
589 <li>no objects have been created</li>
590 </ul>
591 <p/>
592 The VM will call the <code>Agent_OnLoad</code> or
593 <code>Agent_OnLoad_<agent-lib-name></code> function with
594 <i><options></i> as the second argument -
595 that is, using the command-line option examples,
596 <code>"opt1,opt2"</code> will be passed to the <code>char *options</code>
597 argument of <code>Agent_OnLoad</code>.
598 The <code>options</code> argument is encoded as a
599 <internallink id="mUTF">modified UTF-8</internallink> string.
600 If <i>=<options></i> is not specified,
601 a zero length string is passed to <code>options</code>.
602 The lifespan of the <code>options</code> string is the
603 <code>Agent_OnLoad</code> or <code>Agent_OnLoad_<agent-lib-name></code>
604 call. If needed beyond this time the string or parts of the string must
605 be copied.
606 The period between when <code>Agent_OnLoad</code> is called and when it
607 returns is called the <i>OnLoad phase</i>.
608 Since the VM is not initialized during the OnLoad
609 <functionlink id="GetPhase">phase</functionlink>,
610 the set of allowed operations
611 inside <code>Agent_OnLoad</code> is restricted (see the function descriptions for the
612 functionality available at this time).
613 The agent can safely process the options and set
614 event callbacks with <functionlink id="SetEventCallbacks"></functionlink>. Once
615 the VM initialization event is received
616 (that is, the <eventlink id="VMInit">VMInit</eventlink>
617 callback is invoked), the agent
618 can complete its initialization.
619 <rationale>
620 Early startup is required so that agents can set the desired capabilities,
621 many of which must be set before the VM is initialized.
622 In JVMDI, the -Xdebug command-line option provided
623 very coarse-grain control of capabilities.
624 JVMPI implementations use various tricks to provide a single "JVMPI on" switch.
625 No reasonable command-line
626 option could provide the fine-grain of control required to balance needed capabilities vs
627 performance impact.
628 Early startup is also needed so that agents can control the execution
629 environment - modifying the file system and system properties to install
630 their functionality.
631 </rationale>
632 <p/>
633 The return value from <code>Agent_OnLoad</code> or
634 <code>Agent_OnLoad_<agent-lib-name></code> is used to indicate an error.
635 Any value other than zero indicates an error and causes termination of the VM.
636 </intro>
637
638 <intro id="onattach" label="Agent Start-Up (Live phase)">
639 A VM may support a mechanism that allows agents to be started in the VM during the live
640 <functionlink id="GetPhase">phase</functionlink>. The details of how this is supported,
641 are implementation specific. For example, a tool may use some platform specific mechanism,
642 or implementation specific API, to attach to the running VM, and request it start a given
643 agent.
644 <p/>
645 If an agent is started during the live phase then its agent library
646 must export a start-up function
647 with the following prototype:
648 <example>
649 JNIEXPORT jint JNICALL
650 Agent_OnAttach(JavaVM* vm, char *options, void *reserved)</example>
651 Or for a statically linked agent named 'L':
652 <example>
653 JNIEXPORT jint JNICALL
654 Agent_OnAttach_L(JavaVM* vm, char *options, void *reserved)</example>
655
656 <p/>
657 The VM will start the agent by calling this function.
658 It will be called in the context of a thread
659 that is attached to the VM. The first argument <i><vm></i> is the Java VM.
660 The <i><options></i> argument is the startup options provided to the agent.
661 <i><options></i> is encoded as a <internallink id="mUTF">modified UTF-8
662 </internallink> string.
663 If startup options were not provided, a zero length string is passed to
664 <code>options</code>. The lifespan of the <code>options</code> string is the
665 <code>Agent_OnAttach</code> or <code>Agent_OnAttach_<agent-lib-name></code> call.
666 If needed beyond this time the string or parts of the string must be copied.
667 <p/>
668 Note that some <internallink id="capability">capabilities</internallink>
669 may not be available in the live phase.
670 <p/>
671 The <code>Agent_OnAttach</code> or <code>Agent_OnAttach_<agent-lib-name
672 ></code> function initializes the agent and returns a value
673 to the VM to indicate if an error occurred. Any value other than zero indicates an error.
674 An error does not cause the VM to terminate. Instead the VM ignores the error, or takes
675 some implementation specific action -- for example it might print an error to standard error,
676 or record the error in a system log.
677 </intro>
678
679 <intro id="onunload" label="Agent Shutdown">
680 The library may optionally export a
681 shutdown function with the following prototype:
682 <example>
683 JNIEXPORT void JNICALL
684 Agent_OnUnload(JavaVM *vm)</example>
685 Or for a statically linked agent named 'L':
686 <example>
687 JNIEXPORT void JNICALL
688 Agent_OnUnload_L(JavaVM *vm)</example>
689
690 This function will be called by the VM when the library is about to be unloaded.
691 The library will be unloaded (unless it is statically linked into the
692 executable) and this function will be called if some platform specific
693 mechanism causes the unload (an unload mechanism is not specified in this document)
694 or the library is (in effect) unloaded by the termination of the VM whether through
695 normal termination or VM failure, including start-up failure.
696 Uncontrolled shutdown is, of course, an exception to this rule.
697 Note the distinction between this function and the
698 <eventlink id="VMDeath">VM Death event</eventlink>: for the VM Death event
699 to be sent, the VM must have run at least to the point of initialization and a valid
700 <jvmti/> environment must exist which has set a callback for VMDeath
701 and enabled the event.
702 None of these are required for <code>Agent_OnUnload</code> or
703 <code>Agent_OnUnload_<agent-lib-name></code> and this function
704 is also called if the library is unloaded for other reasons.
705 In the case that a VM Death event is sent, it will be sent before this
706 function is called (assuming this function is called due to VM termination).
707 This function can be used to clean-up resources allocated by the agent.
708 </intro>
709
710 <intro id="tooloptions" label="JAVA_TOOL_OPTIONS">
711 Since the command-line cannot always be accessed or modified, for example in embedded VMs
712 or simply VMs launched deep within scripts, a <code>JAVA_TOOL_OPTIONS</code> variable is
713 provided so that agents may be launched in these cases.
714 <p/>
715 Platforms which support environment variables or other named strings, may support the
716 <code>JAVA_TOOL_OPTIONS</code> variable. This variable will be broken into options at white-space
717 boundaries. White-space characters include space, tab, carriage-return, new-line,
718 vertical-tab, and form-feed. Sequences of white-space characters are considered
719 equivalent to a single white-space character. No white-space is included in the options
720 unless quoted. Quoting is as follows:
721 <ul>
722 <li>All characters enclosed between a pair of single quote marks (''), except a single
723 quote, are quoted.</li>
724 <li>Double quote characters have no special meaning inside a pair of single quote marks.</li>
725 <li>All characters enclosed between a pair of double quote marks (""), except a double
726 quote, are quoted.</li>
727 <li>Single quote characters have no special meaning inside a pair of double quote marks.</li>
728 <li>A quoted part can start or end anywhere in the variable.</li>
729 <li>White-space characters have no special meaning when quoted -- they are included in
730 the option like any other character and do not mark white-space boundaries.</li>
731 <li>The pair of quote marks is not included in the option.</li>
732 </ul>
733 <code>JNI_CreateJavaVM</code> (in the JNI Invocation API) will prepend these options to the options supplied
734 in its <code>JavaVMInitArgs</code> argument. Platforms may disable this feature in cases where security is
735 a concern; for example, the Reference Implementation disables this feature on Unix systems when
736 the effective user or group ID differs from the real ID.
737 This feature is intended to support the initialization of tools -- specifically including the
738 launching of native or Java programming language agents. Multiple tools may wish to use this
739 feature, so the variable should not be overwritten, instead, options should be appended to
740 the variable. Note that since the variable is processed at the time of the JNI Invocation
741 API create VM call, options processed by a launcher (e.g., VM selection options) will not be handled.
742 </intro>
743
744 <intro id="environments" label="Environments">
745 The <jvmti/> specification supports the use of multiple simultaneous
746 <jvmti/> agents.
747 Each agent has its own <jvmti/> environment.
748 That is, the <jvmti/> state is
749 separate for each agent - changes to one environment do not affect the
750 others. The state of a <jvmti/>
751 environment includes:
752 <ul>
753 <li><functionlink id="SetEventCallbacks">the event callbacks</functionlink></li>
754 <li><functionlink id="SetEventNotificationMode">the set of events which are enabled</functionlink></li>
755 <li><internallink id="capability">the capabilities</internallink></li>
756 <li><internallink id="memory">the memory allocation/deallocation hooks</internallink></li>
757 </ul>
758 Although their <jvmti/> state
759 is separate, agents inspect and modify the shared state
760 of the VM, they also share the native environment in which they execute.
761 As such, an agent can perturb the results of other agents or cause them
762 to fail. It is the responsibility of the agent writer to specify the level
763 of compatibility with other agents. <jvmti/> implementations are not capable
764 of preventing destructive interactions between agents. Techniques to reduce
765 the likelihood of these occurrences are beyond the scope of this document.
766 <p/>
767 An agent creates a <jvmti/> environment
768 by passing a <jvmti/> version
769 as the interface ID to the JNI Invocation API function
770 <externallink id="jni/invocation.html#getenv">
771 <code>GetEnv</code></externallink>.
772 See <internallink id="jvmtiEnvAccess">Accessing <jvmti/> Functions</internallink>
773 for more details on the creation and use of
774 <jvmti/> environments.
775 Typically, <jvmti/> environments are created by calling <code>GetEnv</code> from
776 <internallink id="onload"><code>Agent_OnLoad</code></internallink>.
777 </intro>
778
779 <intro id="bci" label="Bytecode Instrumentation">
780 This interface does not include some events that one might expect in an interface with
781 profiling support. Some examples include object allocation events and full speed
782 method enter and exit events. The interface instead provides support for
783 <i>bytecode instrumentation</i>, the ability to alter the Java virtual machine
784 bytecode instructions which comprise the target program. Typically, these alterations
785 are to add "events" to the code of a method - for example, to add, at the beginning of a method,
786 a call to <code>MyProfiler.methodEntered()</code>.
787 Since the changes are purely additive, they do not modify application
788 state or behavior.
789 Because the inserted agent code is standard bytecodes, the VM can run at full speed,
790 optimizing not only the target program but also the instrumentation. If the
791 instrumentation does not involve switching from bytecode execution, no expensive
792 state transitions are needed. The result is high performance events.
793 This approach also provides complete control to the agent: instrumentation can be
794 restricted to "interesting" portions of the code (e.g., the end user's code) and
795 can be conditional. Instrumentation can run entirely in Java programming language
796 code or can call into the native agent. Instrumentation can simply maintain
797 counters or can statistically sample events.
798 <p/>
799 Instrumentation can be inserted in one of three ways:
800 <ul>
801 <li>
802 Static Instrumentation: The class file is instrumented before it
803 is loaded into the VM - for example, by creating a duplicate directory of
804 <code>*.class</code> files which have been modified to add the instrumentation.
805 This method is extremely awkward and, in general, an agent cannot know
806 the origin of the class files which will be loaded.
807 </li>
808 <li>
809 Load-Time Instrumentation: When a class file is loaded by the VM, the raw
810 bytes of the class file are sent for instrumentation to the agent.
811 The <eventlink id="ClassFileLoadHook"/>
812 event, triggered by the class load,
813 provides this functionality. This mechanism provides efficient
814 and complete access to one-time instrumentation.
815 </li>
816 <li>
817 Dynamic Instrumentation: A class which is already loaded (and possibly
818 even running) is modified. This optional feature is provided by the
819 <eventlink id="ClassFileLoadHook"/> event, triggered by calling the
820 <functionlink id="RetransformClasses"/> function.
821 Classes can be modified multiple times and can be returned to their
822 original state.
823 The mechanism allows instrumentation which changes during the
824 course of execution.
825 </li>
826 </ul>
827 <p/>
828 The class modification functionality provided in this interface
829 is intended to provide a mechanism for instrumentation
830 (the <eventlink id="ClassFileLoadHook"/> event
831 and the <functionlink id="RetransformClasses"/> function)
832 and, during development, for fix-and-continue debugging
833 (the <functionlink id="RedefineClasses"/> function).
834 <p/>
835 Care must be taken to avoid perturbing dependencies, especially when
836 instrumenting core classes. For example, an approach to getting notification
837 of every object allocation is to instrument the constructor on
838 <code>Object</code>. Assuming that the constructor is initially
839 empty, the constructor could be changed to:
840 <example>
841 public Object() {
842 MyProfiler.allocationTracker(this);
843 }
844 </example>
845 However, if this change was made using the
846 <eventlink id="ClassFileLoadHook"/>
847 event then this might impact a typical VM as follows:
848 the first created object will call the constructor causing a class load of
849 <code>MyProfiler</code>; which will then cause
850 object creation, and since <code>MyProfiler</code> isn't loaded yet,
851 infinite recursion; resulting in a stack overflow. A refinement of this
852 would be to delay invoking the tracking method until a safe time. For
853 example, <code>trackAllocations</code> could be set in the
854 handler for the <code>VMInit</code> event.
855 <example>
856 static boolean trackAllocations = false;
857
858 public Object() {
859 if (trackAllocations) {
860 MyProfiler.allocationTracker(this);
861 }
862 }
863 </example>
864 <p/>
865 The <functionlink id="SetNativeMethodPrefix"/> allows native methods
866 to be instrumented by the use of wrapper methods.
867 </intro>
868
869 <intro id="bcimodules" label="Bytecode Instrumentation of code in modules">
870 Agents can use the functions <functionlink id="AddModuleReads"/>,
871 <functionlink id="AddModuleExports"/>, <functionlink id="AddModuleOpens"/>,
872 <functionlink id="AddModuleUses"/> and <functionlink id="AddModuleProvides"/>
873 to update a module to expand the set of modules that it reads, the set of
874 packages that it exports or opens to other modules, or the services that it
875 uses and provides.
876 <p/>
877 As an aid to agents that deploy supporting classes on the search path of
878 the bootstrap class loader, or the search path of the class loader that
879 loads the main class, the Java virtual machine arranges for the module
880 of classes transformed by the <eventlink id="ClassFileLoadHook"/> event to
881 read the unnamed module of both class loaders.
882 </intro>
883
884 <intro id="mUTF" label="Modified UTF-8 String Encoding">
885 <jvmti/> uses modified UTF-8 to encode character strings.
886 This is the same encoding used by JNI.
887 Modified UTF-8 differs
888 from standard UTF-8 in the representation of supplementary characters
889 and of the null character. See the
890 <externallink id="jni/types.html#modified-utf-8-strings">
891 Modified UTF-8 Strings</externallink>
892 section of the JNI specification for details.
893 </intro>
894
895 <intro id="context" label="Specification Context">
896 Since this interface provides access to the state of applications running in the
897 Java virtual machine;
898 terminology refers to the Java platform and not the native
899 platform (unless stated otherwise). For example:
900 <ul>
901 <li>"thread" means Java programming language thread.</li>
902 <li>"stack frame" means Java virtual machine stack frame.</li>
903 <li>"class" means Java programming language class.</li>
904 <li>"heap" means Java virtual machine heap.</li>
905 <li>"monitor" means Java programming language object monitor.</li>
906 </ul>
907 <p/>
908 Sun, Sun Microsystems, the Sun logo, Java, and JVM
909 are trademarks or registered trademarks of Oracle
910 and/or its affiliates, in the U.S. and other countries.
911 </intro>
912
913
914 <functionsection label="Functions">
915 <intro id="jvmtiEnvAccess" label="Accessing Functions">
916 Native code accesses <jvmti/> features
917 by calling <jvmti/> functions.
918 Access to <jvmti/> functions is by use of an interface pointer
919 in the same manner as
920 <externallink id="jni/design.html">Java
921 Native Interface (JNI) functions</externallink> are accessed.
922 The <jvmti/> interface pointer is called the
923 <i>environment pointer</i>.
924 <p/>
925 An environment pointer is a pointer to an environment and has
926 the type <code>jvmtiEnv*</code>.
927 An environment has information about its <jvmti/> connection.
928 The first value in the environment is a pointer to the function table.
929 The function table is an array of pointers to <jvmti/> functions.
930 Every function pointer is at a predefined offset inside the
931 array.
932 <p/>
933 When used from the C language:
934 double indirection is used to access the functions;
935 the environment pointer provides context and is the first
936 parameter of each function call; for example:
937 <example>
938 jvmtiEnv *jvmti;
939 ...
940 jvmtiError err = (*jvmti)->GetLoadedClasses(jvmti, &class_count, &classes);
941 </example>
942 <p/>
943 When used from the C++ language:
944 functions are accessed as member functions of <code>jvmtiEnv</code>;
945 the environment pointer is not passed to the function call; for example:
946 <example>
947 jvmtiEnv *jvmti;
948 ...
949 jvmtiError err = jvmti->GetLoadedClasses(&class_count, &classes);
950 </example>
951 Unless otherwise stated, all examples and declarations in this
952 specification use the C language.
953 <p/>
954 A <jvmti/> environment can be obtained through the JNI Invocation API
955 <code>GetEnv</code> function:
956 <example>
957 jvmtiEnv *jvmti;
958 ...
959 (*jvm)->GetEnv(jvm, &jvmti, JVMTI_VERSION_1_0);
960 </example>
961 Each call to <code>GetEnv</code>
962 creates a new <jvmti/> connection and thus
963 a new <jvmti/> environment.
964 The <code>version</code> argument of <code>GetEnv</code> must be
965 a <jvmti/> version.
966 The returned environment may have a different version than the
967 requested version but the returned environment must be compatible.
968 <code>GetEnv</code> will return <code>JNI_EVERSION</code> if a
969 compatible version is not available, if <jvmti/> is not supported or
970 <jvmti/> is not supported in the current VM configuration.
971 Other interfaces may be added for creating <jvmti/> environments
972 in specific contexts.
973 Each environment has its own state (for example,
974 <functionlink id="SetEventNotificationMode">desired events</functionlink>,
975 <functionlink id="SetEventCallbacks">event handling functions</functionlink>, and
976 <functionlink id="AddCapabilities">capabilities</functionlink>).
977 An environment is released with
978 <functionlink id="DisposeEnvironment"></functionlink>.
979 Thus, unlike JNI which has one environment per thread, <jvmti/> environments work
980 across threads and are created dynamically.
981 </intro>
982
983 <intro id="functionReturn" label="Function Return Values">
984 <jvmti/> functions always return an
985 <internallink id="ErrorSection">error code</internallink> via the
986 <datalink id="jvmtiError"/> function return value.
987 Some functions can return additional
988 values through pointers provided by the calling function.
989 In some cases, <jvmti/> functions allocate memory that your program must
990 explicitly deallocate. This is indicated in the individual <jvmti/>
991 function descriptions. Empty lists, arrays, sequences, etc are
992 returned as <code>NULL</code>.
993 <p/>
994 In the event that the <jvmti/> function encounters
995 an error (any return value other than <code>JVMTI_ERROR_NONE</code>) the values
996 of memory referenced by argument pointers is undefined, but no memory
997 will have been allocated and no global references will have been allocated.
998 If the error occurs because of invalid input, no action will have occurred.
999 </intro>
1000
1001 <intro id="refs" label="Managing JNI Object References">
1002 <jvmti/> functions identify objects with JNI references
1003 (<datalink id="jobject"/> and <datalink id="jclass"/>)
1004 and their derivatives
1005 (<datalink id="jthread"/> and <datalink id="jthreadGroup"/>).
1006 References passed to
1007 <jvmti/> functions can be either global or local, but they must be
1008 strong references. All references returned by <jvmti/> functions are
1009 local references--these local references are created
1010 during the <jvmti/> call.
1011 Local references are a resource that must be managed (see the
1012 <externallink id="jni/functions.html#local-references">
1013 JNI Documentation</externallink>).
1014 When threads return from native code all local references
1015 are freed. Note that some threads, including typical
1016 agent threads, will never return from native code.
1017 A thread is ensured the ability to create sixteen local
1018 references without the need for any explicit management.
1019 For threads executing a limited number of <jvmti/> calls before
1020 returning from native code
1021 (for example, threads processing events),
1022 it may be determined that no explicit management
1023 is needed.
1024 However, long running agent threads will need explicit
1025 local reference management--usually with the JNI functions
1026 <code>PushLocalFrame</code> and <code>PopLocalFrame</code>.
1027 Conversely, to preserve references beyond the
1028 return from native code, they must be converted to global references.
1029 These rules do not apply to <datalink id="jmethodID"/> and <datalink id="jfieldID"/>
1030 as they are not <datalink id="jobject"/>s.
1031 </intro>
1032
1033 <intro id="prereqState" label="Prerequisite State for Calling Functions">
1034 Unless the function explicitly states that the agent must bring
1035 a thread or the VM to a particular state (for example, suspended),
1036 the <jvmti/> implementation is responsible for bringing the VM to a
1037 safe and consistent state for performing the function.
1038 </intro>
1039
1040 <intro id="functionsExceptions" label="Exceptions and Functions">
1041 <jvmti/> functions never throw exceptions; error conditions are
1042 communicated via the
1043 <internallink id="functionReturn">function return value</internallink>.
1044 Any existing exception state is preserved across a call to a
1045 <jvmti/> function.
1046 See the
1047 <externallink
1048 id="jni/design.html#java-exceptions"
1049 >Java Exceptions</externallink>
1050 section of the JNI specification for information on handling exceptions.
1051 </intro>
1052
1053 <category id="memory" label="Memory Management">
1054 <intro>
1055 These functions provide for the allocation and deallocation of
1056 memory used by <jvmti/> functionality and can be used to provide
1057 working memory for agents.
1058 Memory managed by <jvmti/> is not compatible with other memory
1059 allocation libraries and mechanisms.
1060 </intro>
1061
1062 <function id="Allocate" jkernel="yes" phase="any" callbacksafe="safe" impl="notrace" num="46">
1063 <synopsis>Allocate</synopsis>
1064 <description>
1065 Allocate an area of memory through the <jvmti/> allocator.
1066 The allocated
1067 memory should be freed with <functionlink id="Deallocate"></functionlink>.
1068 </description>
1069 <origin>jvmdi</origin>
1070 <capabilities>
1071 </capabilities>
1072 <parameters>
1073 <param id="size">
1074 <jlong/>
1075 <description>
1076 The number of bytes to allocate.
1077 <rationale>
1078 <code>jlong</code> is used for compatibility with JVMDI.
1079 </rationale>
1080 </description>
1081 </param>
1082 <param id="mem_ptr">
1083 <allocbuf incount="size"><uchar/></allocbuf>
1084 <description>
1085 On return, a pointer to the beginning of the allocated memory.
1086 If <code>size</code> is zero, <code>NULL</code> is returned.
1087 </description>
1088 </param>
1089 </parameters>
1090 <errors>
1091 <error id="JVMTI_ERROR_OUT_OF_MEMORY">
1092 Memory request cannot be honored.
1093 </error>
1094 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
1095 <paramlink id="size"></paramlink> is less than zero.
1096 </error>
1097 </errors>
1098 </function>
1099
1100 <function id="Deallocate" jkernel="yes" phase="any" callbacksafe="safe" impl="notrace" num="47">
1101 <synopsis>Deallocate</synopsis>
1102 <description>
1103 Deallocate <code>mem</code> using the <jvmti/> allocator.
1104 This function should
1105 be used to deallocate any memory allocated and returned
1106 by a <jvmti/> function
1107 (including memory allocated with <functionlink id="Allocate"></functionlink>).
1108 All allocated memory must be deallocated
1109 or the memory cannot be reclaimed.
1110 </description>
1111 <origin>jvmdi</origin>
1112 <capabilities>
1113 </capabilities>
1114 <parameters>
1115 <param id="mem">
1116 <outbuf>
1117 <uchar/>
1118 <nullok>the call is ignored</nullok>
1119 </outbuf>
1120 <description>
1121 A pointer to the beginning of the allocated memory.
1122 Please ignore "On return, the elements are set."
1123 <todo>keep it from generating "On return, the elements are set"</todo>
1124 </description>
1125 </param>
1126 </parameters>
1127 <errors>
1128 </errors>
1129 </function>
1130 </category>
1131
1132 <category id="threadCategory" label="Thread">
1133 <intro>
1134 </intro>
1135
1136 <function id="GetThreadState" num="17">
1137 <synopsis>Get Thread State</synopsis>
1138 <description>
1139 Get the state of a thread. The state of the thread is represented by the
1140 answers to the hierarchical set of questions below:
1141 <ul type="circle">
1142 <li><i>Alive?</i>
1143 <ul>
1144 <li>Not alive.
1145 <ul type="circle">
1146 <li><i>Why not alive?</i>
1147 <ul>
1148 <li>New.</li>
1149 <li>Terminated (<datalink
1150 id="JVMTI_THREAD_STATE_TERMINATED"><code>JVMTI_THREAD_STATE_TERMINATED</code></datalink>)</li>
1151 </ul>
1152 </li>
1153 </ul>
1154 </li>
1155 <li>Alive (<datalink
1156 id="JVMTI_THREAD_STATE_ALIVE"><code>JVMTI_THREAD_STATE_ALIVE</code></datalink>)
1157 <ul type="circle">
1158 <li><i>Suspended?</i>
1159 <ul>
1160 <li>Suspended (<datalink
1161 id="JVMTI_THREAD_STATE_SUSPENDED"><code>JVMTI_THREAD_STATE_SUSPENDED</code></datalink>)</li>
1162 <li>Not suspended</li>
1163 </ul>
1164 </li>
1165 <li><i>Interrupted?</i>
1166 <ul>
1167 <li>Interrupted (<datalink
1168 id="JVMTI_THREAD_STATE_INTERRUPTED"><code>JVMTI_THREAD_STATE_INTERRUPTED</code></datalink>)</li>
1169 <li>Not interrupted.</li>
1170 </ul>
1171 </li>
1172 <li><i>In native?</i>
1173 <ul>
1174 <li>In native code (<datalink
1175 id="JVMTI_THREAD_STATE_IN_NATIVE"><code>JVMTI_THREAD_STATE_IN_NATIVE</code></datalink>)</li>
1176 <li>In Java programming language code</li>
1177 </ul>
1178 </li>
1179 <li><i>What alive state?</i>
1180 <ul>
1181 <li>Runnable (<datalink
1182 id="JVMTI_THREAD_STATE_RUNNABLE"><code>JVMTI_THREAD_STATE_RUNNABLE</code></datalink>)</li>
1183 <li>Blocked (<datalink
1184 id="JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER"><code>JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER</code></datalink>)</li>
1185 <li>Waiting (<datalink
1186 id="JVMTI_THREAD_STATE_WAITING"><code>JVMTI_THREAD_STATE_WAITING</code></datalink>)
1187 <ul type="circle">
1188 <li><i>Timed wait?</i>
1189 <ul>
1190 <li>Indefinite (<datalink
1191 id="JVMTI_THREAD_STATE_WAITING_INDEFINITELY"><code>JVMTI_THREAD_STATE_WAITING_INDEFINITELY</code></datalink></li>
1192 <li>Timed (<datalink
1193 id="JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT"><code>JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT</code></datalink>)</li>
1194 </ul>
1195 </li>
1196 <li><i>Why waiting?</i>
1197 <ul>
1198 <li>Object.wait (<datalink
1199 id="JVMTI_THREAD_STATE_IN_OBJECT_WAIT"><code>JVMTI_THREAD_STATE_IN_OBJECT_WAIT</code></datalink>)</li>
1200 <li>LockSupport.park (<datalink
1201 id="JVMTI_THREAD_STATE_PARKED"><code>JVMTI_THREAD_STATE_PARKED</code></datalink>)</li>
1202 <li>Sleeping (<datalink
1203 id="JVMTI_THREAD_STATE_SLEEPING"><code>JVMTI_THREAD_STATE_SLEEPING</code></datalink>)</li>
1204 </ul>
1205 </li>
1206 </ul>
1207 </li>
1208 </ul>
1209 </li>
1210 </ul>
1211 </li>
1212 </ul>
1213 </li>
1214 </ul>
1215 <p/>
1216 The answers are represented by the following bit vector.
1217 <constants id="jvmtiThreadState" label="Thread State Flags" kind="bits">
1218 <constant id="JVMTI_THREAD_STATE_ALIVE" num="0x0001">
1219 Thread is alive. Zero if thread is new (not started) or terminated.
1220 </constant>
1221 <constant id="JVMTI_THREAD_STATE_TERMINATED" num="0x0002">
1222 Thread has completed execution.
1223 </constant>
1224 <constant id="JVMTI_THREAD_STATE_RUNNABLE" num="0x0004">
1225 Thread is runnable.
1226 </constant>
1227 <constant id="JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER" num="0x0400">
1228 Thread is waiting to enter a synchronization block/method or,
1229 after an <code>Object.wait()</code>, waiting to re-enter a
1230 synchronization block/method.
1231 </constant>
1232 <constant id="JVMTI_THREAD_STATE_WAITING" num="0x0080">
1233 Thread is waiting.
1234 </constant>
1235 <constant id="JVMTI_THREAD_STATE_WAITING_INDEFINITELY" num="0x0010">
1236 Thread is waiting without a timeout.
1237 For example, <code>Object.wait()</code>.
1238 </constant>
1239 <constant id="JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT" num="0x0020">
1240 Thread is waiting with a maximum time to wait specified.
1241 For example, <code>Object.wait(long)</code>.
1242 </constant>
1243 <constant id="JVMTI_THREAD_STATE_SLEEPING" num="0x0040">
1244 Thread is sleeping -- <code>Thread.sleep(long)</code>.
1245 </constant>
1246 <constant id="JVMTI_THREAD_STATE_IN_OBJECT_WAIT" num="0x0100">
1247 Thread is waiting on an object monitor -- <code>Object.wait</code>.
1248 </constant>
1249 <constant id="JVMTI_THREAD_STATE_PARKED" num="0x0200">
1250 Thread is parked, for example: <code>LockSupport.park</code>,
1251 <code>LockSupport.parkUtil</code> and <code>LockSupport.parkNanos</code>.
1252 </constant>
1253 <constant id="JVMTI_THREAD_STATE_SUSPENDED" num="0x100000">
1254 Thread suspended.
1255 <code>java.lang.Thread.suspend()</code>
1256 or a <jvmti/> suspend function
1257 (such as <functionlink id="SuspendThread"></functionlink>)
1258 has been called on the thread. If this bit
1259 is set, the other bits refer to the thread state before suspension.
1260 </constant>
1261 <constant id="JVMTI_THREAD_STATE_INTERRUPTED" num="0x200000">
1262 Thread has been interrupted.
1263 </constant>
1264 <constant id="JVMTI_THREAD_STATE_IN_NATIVE" num="0x400000">
1265 Thread is in native code--that is, a native method is running
1266 which has not called back into the VM or Java programming
1267 language code.
1268 <p/>
1269 This flag is not set when running VM compiled Java programming
1270 language code nor is it set when running VM code or
1271 VM support code. Native VM interface functions, such as JNI and
1272 <jvmti/> functions, may be implemented as VM code.
1273 </constant>
1274 <constant id="JVMTI_THREAD_STATE_VENDOR_1" num="0x10000000">
1275 Defined by VM vendor.
1276 </constant>
1277 <constant id="JVMTI_THREAD_STATE_VENDOR_2" num="0x20000000">
1278 Defined by VM vendor.
1279 </constant>
1280 <constant id="JVMTI_THREAD_STATE_VENDOR_3" num="0x40000000">
1281 Defined by VM vendor.
1282 </constant>
1283 </constants>
1284 The following definitions are used to convert <jvmti/> thread state
1285 to <code>java.lang.Thread.State</code> style states.
1286 <constants id="jvmtiJavaLangThreadState" label="java.lang.Thread.State Conversion Masks" kind="bits">
1287 <constant id="JVMTI_JAVA_LANG_THREAD_STATE_MASK"
1288 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">
1289 Mask the state with this before comparison
1290 </constant>
1291 <constant id="JVMTI_JAVA_LANG_THREAD_STATE_NEW"
1292 num="0">
1293 <code>java.lang.Thread.State.NEW</code>
1294 </constant>
1295 <constant id="JVMTI_JAVA_LANG_THREAD_STATE_TERMINATED"
1296 num="JVMTI_THREAD_STATE_TERMINATED">
1297 <code>java.lang.Thread.State.TERMINATED</code>
1298 </constant>
1299 <constant id="JVMTI_JAVA_LANG_THREAD_STATE_RUNNABLE"
1300 num="JVMTI_THREAD_STATE_ALIVE | JVMTI_THREAD_STATE_RUNNABLE">
1301 <code>java.lang.Thread.State.RUNNABLE</code>
1302 </constant>
1303 <constant id="JVMTI_JAVA_LANG_THREAD_STATE_BLOCKED"
1304 num="JVMTI_THREAD_STATE_ALIVE | JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER">
1305 <code>java.lang.Thread.State.BLOCKED</code>
1306 </constant>
1307 <constant id="JVMTI_JAVA_LANG_THREAD_STATE_WAITING"
1308 num="JVMTI_THREAD_STATE_ALIVE | JVMTI_THREAD_STATE_WAITING | JVMTI_THREAD_STATE_WAITING_INDEFINITELY">
1309 <code>java.lang.Thread.State.WAITING</code>
1310 </constant>
1311 <constant id="JVMTI_JAVA_LANG_THREAD_STATE_TIMED_WAITING"
1312 num="JVMTI_THREAD_STATE_ALIVE | JVMTI_THREAD_STATE_WAITING | JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT">
1313 <code>java.lang.Thread.State.TIMED_WAITING</code>
1314 </constant>
1315 </constants>
1316 <b>Rules</b>
1317 <p/>
1318 There can be no more than one answer to a question, although there can be no
1319 answer (because the answer is unknown, does not apply, or none of the answers is
1320 correct). An answer is set only when the enclosing answers match.
1321 That is, no more than one of
1322 <ul type="circle">
1323 <li><code>JVMTI_THREAD_STATE_RUNNABLE</code></li>
1324 <li><code>JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER</code></li>
1325 <li><code>JVMTI_THREAD_STATE_WAITING</code></li>
1326 </ul>
1327 can be set (a <tm>J2SE</tm> compliant implementation will always set
1328 one of these if <code>JVMTI_THREAD_STATE_ALIVE</code> is set).
1329 And if any of these are set, the enclosing answer
1330 <code>JVMTI_THREAD_STATE_ALIVE</code> is set.
1331 No more than one of
1332 <ul type="circle">
1333 <li><code>JVMTI_THREAD_STATE_WAITING_INDEFINITELY</code></li>
1334 <li><code>JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT</code></li>
1335 </ul>
1336 can be set (a <tm>J2SE</tm> compliant implementation will always set
1337 one of these if <code>JVMTI_THREAD_STATE_WAITING</code> is set).
1338 And if either is set, the enclosing answers
1339 <code>JVMTI_THREAD_STATE_ALIVE</code> and
1340 <code>JVMTI_THREAD_STATE_WAITING</code> are set.
1341 No more than one of
1342 <ul type="circle">
1343 <li><code>JVMTI_THREAD_STATE_IN_OBJECT_WAIT</code></li>
1344 <li><code>JVMTI_THREAD_STATE_PARKED</code></li>
1345 <li><code>JVMTI_THREAD_STATE_SLEEPING</code></li>
1346 </ul>
1347 can be set. And if any of these is set, the enclosing answers
1348 <code>JVMTI_THREAD_STATE_ALIVE</code> and
1349 <code>JVMTI_THREAD_STATE_WAITING</code> are set.
1350 Also, if <code>JVMTI_THREAD_STATE_SLEEPING</code> is set,
1351 then <code>JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT</code> is set.
1352 If a state <i>A</i> is implemented using the mechanism of
1353 state <i>B</i> then it is state <i>A</i> which
1354 is returned by this function.
1355 For example, if <code>Thread.sleep(long)</code>
1356 is implemented using <code>Object.wait(long)</code>
1357 then it is still <code>JVMTI_THREAD_STATE_SLEEPING</code>
1358 which is returned.
1359 More than one of
1360 <ul type="circle">
1361 <li><code>JVMTI_THREAD_STATE_SUSPENDED</code></li>
1362 <li><code>JVMTI_THREAD_STATE_INTERRUPTED</code></li>
1363 <li><code>JVMTI_THREAD_STATE_IN_NATIVE</code></li>
1364 </ul>
1365 can be set, but if any is set,
1366 <code>JVMTI_THREAD_STATE_ALIVE</code> is set.
1367 <p/>
1368 And finally,
1369 <code>JVMTI_THREAD_STATE_TERMINATED</code> cannot be set unless
1370 <code>JVMTI_THREAD_STATE_ALIVE</code> is not set.
1371 <p/>
1372 The thread state representation is designed for extension in future versions
1373 of the specification; thread state values should be used accordingly, that is
1374 they should not be used as ordinals.
1375 Most queries can be made by testing a single bit, if use in a switch statement is desired,
1376 the state bits should be masked with the interesting bits.
1377 All bits not defined above are reserved for future use.
1378 A VM, compliant to the current specification, must set reserved bits to zero.
1379 An agent should ignore reserved bits --
1380 they should not be assumed to be zero and thus should not be included in comparisons.
1381 <p/>
1382 <b>Examples</b>
1383 <p/>
1384 Note that the values below exclude reserved and vendor bits.
1385 <p/>
1386 The state of a thread blocked at a <code>synchronized</code>-statement would be:
1387 <example>
1388 JVMTI_THREAD_STATE_ALIVE + JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER
1389 </example>
1390 The state of a thread which hasn't started yet would be:
1391 <example>
1392 0
1393 </example>
1394 The state of a thread at a <code>Object.wait(3000)</code> would be:
1395 <example>
1396 JVMTI_THREAD_STATE_ALIVE + JVMTI_THREAD_STATE_WAITING +
1397 JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT +
1398 JVMTI_THREAD_STATE_MONITOR_WAITING
1399 </example>
1400 The state of a thread suspended while runnable would be:
1401 <example>
1402 JVMTI_THREAD_STATE_ALIVE + JVMTI_THREAD_STATE_RUNNABLE + JVMTI_THREAD_STATE_SUSPENDED
1403 </example>
1404 <p/>
1405 <b>Testing the State</b>
1406 <p/>
1407 In most cases, the thread state can be determined by testing the one bit corresponding
1408 to that question. For example, the code to test if a thread is sleeping:
1409 <example>
1410 jint state;
1411 jvmtiError err;
1412
1413 err = (*jvmti)->GetThreadState(jvmti, thread, &state);
1414 if (err == JVMTI_ERROR_NONE) {
1415 if (state & JVMTI_THREAD_STATE_SLEEPING) { ...
1416 </example>
1417 <p/>
1418 For waiting (that is, in <code>Object.wait</code>, parked, or sleeping) it would be:
1419 <example>
1420 if (state & JVMTI_THREAD_STATE_WAITING) { ...
1421 </example>
1422 For some states, more than one bit will need to be tested as is the case
1423 when testing if a thread has not yet been started:
1424 <example>
1425 if ((state & (JVMTI_THREAD_STATE_ALIVE | JVMTI_THREAD_STATE_TERMINATED)) == 0) { ...
1426 </example>
1427 To distinguish timed from untimed <code>Object.wait</code>:
1428 <example>
1429 if (state & JVMTI_THREAD_STATE_IN_OBJECT_WAIT) {
1430 if (state & JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT) {
1431 printf("in Object.wait(long timeout)\n");
1432 } else {
1433 printf("in Object.wait()\n");
1434 }
1435 }
1436 </example>
1437 <p/>
1438 <b>Relationship to <code>java.lang.Thread.State</code></b>
1439 <p/>
1440 The thread state represented by <code>java.lang.Thread.State</code>
1441 returned from <code>java.lang.Thread.getState()</code> is a subset of the
1442 information returned from this function.
1443 The corresponding <code>java.lang.Thread.State</code> can be determined
1444 by using the provided conversion masks.
1445 For example, this returns the name of the <code>java.lang.Thread.State</code> thread state:
1446 <example>
1447 err = (*jvmti)->GetThreadState(jvmti, thread, &state);
1448 abortOnError(err);
1449 switch (state & JVMTI_JAVA_LANG_THREAD_STATE_MASK) {
1450 case JVMTI_JAVA_LANG_THREAD_STATE_NEW:
1451 return "NEW";
1452 case JVMTI_JAVA_LANG_THREAD_STATE_TERMINATED:
1453 return "TERMINATED";
1454 case JVMTI_JAVA_LANG_THREAD_STATE_RUNNABLE:
1455 return "RUNNABLE";
1456 case JVMTI_JAVA_LANG_THREAD_STATE_BLOCKED:
1457 return "BLOCKED";
1458 case JVMTI_JAVA_LANG_THREAD_STATE_WAITING:
1459 return "WAITING";
1460 case JVMTI_JAVA_LANG_THREAD_STATE_TIMED_WAITING:
1461 return "TIMED_WAITING";
1462 }
1463 </example>
1464 </description>
1465 <origin>new</origin>
1466 <capabilities>
1467 </capabilities>
1468 <parameters>
1469 <param id="thread">
1470 <jthread null="current" started="maybe" impl="noconvert"/>
1471 <description>
1472 The thread to query.
1473 </description>
1474 </param>
1475 <param id="thread_state_ptr">
1476 <outptr><jint/></outptr>
1477 <description>
1478 On return, points to state flags,
1479 as defined by the <internallink id="jvmtiThreadState">Thread State Flags</internallink>.
1480 </description>
1481 </param>
1482 </parameters>
1483 <errors>
1484 </errors>
1485 </function>
1486
1487 <function id="GetCurrentThread" phase="start" num="18" since="1.1">
1488 <synopsis>Get Current Thread</synopsis>
1489 <description>
1490 Get the current thread.
1491 The current thread is the Java programming language thread which has called the function.
1492 The function may return <code>NULL</code> in the start phase if the
1493 <internallink id="jvmtiCapabilities.can_generate_early_vmstart">
1494 <code>can_generate_early_vmstart</code></internallink> capability is enabled
1495 and the <code>java.lang.Thread</code> class has not been initialized yet.
1496 <p/>
1497 Note that most <jvmti/> functions that take a thread
1498 as an argument will accept <code>NULL</code> to mean
1499 the current thread.
1500 </description>
1501 <origin>new</origin>
1502 <capabilities>
1503 </capabilities>
1504 <parameters>
1505 <param id="thread_ptr">
1506 <outptr><jthread/></outptr>
1507 <description>
1508 On return, points to the current thread, or <code>NULL</code>.
1509 </description>
1510 </param>
1511 </parameters>
1512 <errors>
1513 </errors>
1514 </function>
1515
1516 <function id="GetAllThreads" num="4">
1517 <synopsis>Get All Threads</synopsis>
1518 <description>
1519 Get all live threads.
1520 The threads are Java programming language threads;
1521 that is, threads that are attached to the VM.
1522 A thread is live if <code>java.lang.Thread.isAlive()</code>
1523 would return <code>true</code>, that is, the thread has
1524 been started and has not yet died.
1525 The universe of threads is determined by the context of the <jvmti/>
1526 environment, which typically is all threads attached to the VM.
1527 Note that this includes <jvmti/> agent threads
1528 (see <functionlink id="RunAgentThread"/>).
1529 </description>
1530 <origin>jvmdi</origin>
1531 <capabilities>
1532 </capabilities>
1533 <parameters>
1534 <param id="threads_count_ptr">
1535 <outptr><jint/></outptr>
1536 <description>
1537 On return, points to the number of running threads.
1538 </description>
1539 </param>
1540 <param id="threads_ptr">
1541 <allocbuf outcount="threads_count_ptr"><jthread/></allocbuf>
1542 <description>
1543 On return, points to an array of references, one
1544 for each running thread.
1545 </description>
1546 </param>
1547 </parameters>
1548 <errors>
1549 </errors>
1550 </function>
1551
1552 <function id="SuspendThread" num="5">
1553 <synopsis>Suspend Thread</synopsis>
1554 <description>
1555 Suspend the specified thread. If the calling thread is specified,
1556 this function will not return until some other thread calls
1557 <functionlink id="ResumeThread"></functionlink>.
1558 If the thread is currently suspended, this function
1559 does nothing and returns an error.
1560 </description>
1561 <origin>jvmdi</origin>
1562 <capabilities>
1563 <required id="can_suspend"></required>
1564 </capabilities>
1565 <parameters>
1566 <param id="thread">
1567 <jthread null="current"/>
1568 <description>
1569 The thread to suspend.
1570 </description>
1571 </param>
1572 </parameters>
1573 <errors>
1574 <error id="JVMTI_ERROR_THREAD_SUSPENDED">
1575 Thread already suspended.
1576 </error>
1577 </errors>
1578 </function>
1579
1580 <elide>
1581 <function id="SuspendAllThreads" num="101">
1582 <synopsis>Suspend All Threads</synopsis>
1583 <description>
1584 <issue>
1585 There has been no explicit call for this function, and it will
1586 thus be removed if there is no interest.
1587 </issue>
1588 Suspend all live threads except:
1589 <ul>
1590 <li>already suspended threads</li>
1591 <li>those listed in <paramlink id="except_list"></paramlink></li>
1592 <li>certain system (non application) threads, as determined
1593 by the VM implementation</li>
1594 </ul>
1595 The threads are Java programming language threads;
1596 native threads which are not attached to the VM are not
1597 Java programming language threads.
1598 A thread is live if <code>java.lang.Thread.isAlive()</code>
1599 would return <code>true</code>, that is, the thread has
1600 been started and has not yet died.
1601 The universe of threads is determined
1602 by the context of the <jvmti/>
1603 environment, which, typically, is all threads attached to the VM,
1604 except critical VM internal threads and <jvmti/> agent threads
1605 (see <functionlink id="RunAgentThread"/>).
1606 <p/>
1607 If the calling thread is specified,
1608 all other threads are suspended first then the caller thread is suspended -
1609 this function will not return until some other thread calls
1610 <functionlink id="ResumeThread"></functionlink>.
1611 <p/>
1612 The list of actually
1613 suspended threads is returned in
1614 <paramlink id="suspended_list_ptr"></paramlink>.
1615 Suspension is as defined in <functionlink id="SuspendThread"></functionlink>.
1616 <functionlink id="ResumeThreadList"></functionlink>
1617 can be used to resume the suspended threads.
1618 </description>
1619 <origin>new</origin>
1620 <capabilities>
1621 <required id="can_suspend"></required>
1622 </capabilities>
1623 <parameters>
1624 <param id="except_count">
1625 <jint min="0"/>
1626 <description>
1627 The number of threads in the list of threads not to be suspended.
1628 </description>
1629 </param>
1630 <param id="except_list">
1631 <inbuf incount="except_count">
1632 <jthread/>
1633 <nullok>not an error if <code>except_count == 0</code></nullok>
1634 </inbuf>
1635 <description>
1636 The list of threads not to be suspended.
1637 </description>
1638 </param>
1639 <param id="suspended_count_ptr">
1640 <outptr><jint/></outptr>
1641 <description>
1642 On return, points to the number of threads suspended by this call.
1643 </description>
1644 </param>
1645 <param id="suspended_list_ptr">
1646 <allocbuf outcount="suspended_count_ptr"><jthread/></allocbuf>
1647 <description>
1648 On return, points to an array of references, one
1649 for each thread suspended.
1650 </description>
1651 </param>
1652 </parameters>
1653 <errors>
1654 <error id="JVMTI_ERROR_INVALID_THREAD">
1655 A thread in <paramlink id="except_list"></paramlink> was invalid.
1656 </error>
1657 <error id="JVMTI_ERROR_NULL_POINTER">
1658 Both <paramlink id="except_list"></paramlink> was <code>NULL</code>
1659 and <paramlink id="except_count"></paramlink> was non-zero.
1660 </error>
1661 </errors>
1662 </function>
1663 </elide>
1664
1665 <function id="SuspendThreadList" num="92">
1666 <synopsis>Suspend Thread List</synopsis>
1667 <description>
1668 Suspend the <paramlink id="request_count"></paramlink>
1669 threads specified in the
1670 <paramlink id="request_list"></paramlink> array.
1671 Threads may be resumed with
1672 <functionlink id="ResumeThreadList"></functionlink> or
1673 <functionlink id="ResumeThread"></functionlink>.
1674 If the calling thread is specified in the
1675 <paramlink id="request_list"></paramlink> array, this function will
1676 not return until some other thread resumes it.
1677 Errors encountered in the suspension of a thread
1678 are returned in the <paramlink id="results"></paramlink>
1679 array, <b>not</b> in the return value of this function.
1680 Threads that are currently suspended do not change state.
1681 </description>
1682 <origin>jvmdi</origin>
1683 <capabilities>
1684 <required id="can_suspend"></required>
1685 </capabilities>
1686 <parameters>
1687 <param id="request_count">
1688 <jint min="0"/>
1689 <description>
1690 The number of threads to suspend.
1691 </description>
1692 </param>
1693 <param id="request_list">
1694 <inbuf incount="request_count"><jthread/></inbuf>
1695 <description>
1696 The list of threads to suspend.
1697 </description>
1698 </param>
1699 <param id="results">
1700 <outbuf incount="request_count"><enum>jvmtiError</enum></outbuf>
1701 <description>
1702 An agent supplied array of
1703 <paramlink id="request_count"></paramlink> elements.
1704 On return, filled with the error code for
1705 the suspend of the corresponding thread.
1706 The error code will be
1707 <errorlink id="JVMTI_ERROR_NONE"></errorlink>
1708 if the thread was suspended by this call.
1709 Possible error codes are those specified
1710 for <functionlink id="SuspendThread"></functionlink>.
1711 </description>
1712 </param>
1713 </parameters>
1714 <errors>
1715 </errors>
1716 </function>
1717
1718 <function id="ResumeThread" num="6">
1719 <synopsis>Resume Thread</synopsis>
1720 <description>
1721 Resume a suspended thread.
1722 Any threads currently suspended through
1723 a <jvmti/> suspend function (eg.
1724 <functionlink id="SuspendThread"></functionlink>)
1725 or <code>java.lang.Thread.suspend()</code>
1726 will resume execution;
1727 all other threads are unaffected.
1728 </description>
1729 <origin>jvmdi</origin>
1730 <capabilities>
1731 <required id="can_suspend"></required>
1732 </capabilities>
1733 <parameters>
1734 <param id="thread">
1735 <jthread/>
1736 <description>
1737 The thread to resume.
1738 </description>
1739 </param>
1740 </parameters>
1741 <errors>
1742 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
1743 Thread was not suspended.
1744 </error>
1745 <error id="JVMTI_ERROR_INVALID_TYPESTATE">
1746 The state of the thread has been modified, and is now inconsistent.
1747 </error>
1748 </errors>
1749 </function>
1750
1751 <function id="ResumeThreadList" num="93">
1752 <synopsis>Resume Thread List</synopsis>
1753 <description>
1754 Resume the <paramlink id="request_count"></paramlink>
1755 threads specified in the
1756 <paramlink id="request_list"></paramlink> array.
1757 Any thread suspended through
1758 a <jvmti/> suspend function (eg.
1759 <functionlink id="SuspendThreadList"></functionlink>)
1760 or <code>java.lang.Thread.suspend()</code>
1761 will resume execution.
1762 </description>
1763 <origin>jvmdi</origin>
1764 <capabilities>
1765 <required id="can_suspend"></required>
1766 </capabilities>
1767 <parameters>
1768 <param id="request_count">
1769 <jint min="0"/>
1770 <description>
1771 The number of threads to resume.
1772 </description>
1773 </param>
1774 <param id="request_list">
1775 <inbuf incount="request_count"><jthread/></inbuf>
1776 <description>
1777 The threads to resume.
1778 </description>
1779 </param>
1780 <param id="results">
1781 <outbuf incount="request_count"><enum>jvmtiError</enum></outbuf>
1782 <description>
1783 An agent supplied array of
1784 <paramlink id="request_count"></paramlink> elements.
1785 On return, filled with the error code for
1786 the resume of the corresponding thread.
1787 The error code will be
1788 <errorlink id="JVMTI_ERROR_NONE"></errorlink>
1789 if the thread was suspended by this call.
1790 Possible error codes are those specified
1791 for <functionlink id="ResumeThread"></functionlink>.
1792 </description>
1793 </param>
1794 </parameters>
1795 <errors>
1796 </errors>
1797 </function>
1798
1799 <function id="StopThread" num="7">
1800 <synopsis>Stop Thread</synopsis>
1801 <description>
1802 Send the specified asynchronous exception to the specified thread
1803 (similar to <code>java.lang.Thread.stop</code>).
1804 Normally, this function is used to kill the specified thread with an
1805 instance of the exception <code>ThreadDeath</code>.
1806 </description>
1807 <origin>jvmdi</origin>
1808 <capabilities>
1809 <required id="can_signal_thread"></required>
1810 </capabilities>
1811 <parameters>
1812 <param id="thread">
1813 <jthread/>
1814 <description>
1815 The thread to stop.
1816 </description>
1817 </param>
1818 <param id="exception">
1819 <jobject/>
1820 <description>
1821 The asynchronous exception object.
1822 </description>
1823 </param>
1824 </parameters>
1825 <errors>
1826 </errors>
1827 </function>
1828
1829 <function id="InterruptThread" num="8">
1830 <synopsis>Interrupt Thread</synopsis>
1831 <description>
1832 Interrupt the specified thread
1833 (similar to <code>java.lang.Thread.interrupt</code>).
1834 </description>
1835 <origin>jvmdi</origin>
1836 <capabilities>
1837 <required id="can_signal_thread"></required>
1838 </capabilities>
1839 <parameters>
1840 <param id="thread">
1841 <jthread impl="noconvert"/>
1842 <description>
1843 The thread to interrupt.
1844 </description>
1845 </param>
1846 </parameters>
1847 <errors>
1848 </errors>
1849 </function>
1850
1851 <function id="GetThreadInfo" num="9">
1852 <synopsis>Get Thread Info</synopsis>
1853 <typedef id="jvmtiThreadInfo" label="Thread information structure">
1854 <field id="name">
1855 <allocfieldbuf><char/></allocfieldbuf>
1856 <description>
1857 The thread name, encoded as a
1858 <internallink id="mUTF">modified UTF-8</internallink> string.
1859 </description>
1860 </field>
1861 <field id="priority">
1862 <jint/>
1863 <description>
1864 The thread priority. See the thread priority constants:
1865 <datalink id="jvmtiThreadPriority"></datalink>.
1866 </description>
1867 </field>
1868 <field id="is_daemon">
1869 <jboolean/>
1870 <description>
1871 Is this a daemon thread?
1872 </description>
1873 </field>
1874 <field id="thread_group">
1875 <jthreadGroup/>
1876 <description>
1877 The thread group to which this thread belongs.
1878 <code>NULL</code> if the thread has died.
1879 </description>
1880 </field>
1881 <field id="context_class_loader">
1882 <jobject/>
1883 <description>
1884 The context class loader associated with this thread.
1885 </description>
1886 </field>
1887 </typedef>
1888 <description>
1889 Get thread information. The fields of the <datalink id="jvmtiThreadInfo"/> structure
1890 are filled in with details of the specified thread.
1891 </description>
1892 <origin>jvmdi</origin>
1893 <capabilities>
1894 </capabilities>
1895 <parameters>
1896 <param id="thread">
1897 <jthread null="current" impl="noconvert" started="maybe"/>
1898 <description>
1899 The thread to query.
1900 </description>
1901 </param>
1902 <param id="info_ptr">
1903 <outptr><struct>jvmtiThreadInfo</struct></outptr>
1904 <description>
1905 On return, filled with information describing the specified thread.
1906 </description>
1907 </param>
1908 </parameters>
1909 <errors>
1910 </errors>
1911 </function>
1912
1913 <function id="GetOwnedMonitorInfo" num="10">
1914 <synopsis>Get Owned Monitor Info</synopsis>
1915 <description>
1916 Get information about the monitors owned by the
1917 specified thread.
1918 </description>
1919 <origin>jvmdiClone</origin>
1920 <capabilities>
1921 <required id="can_get_owned_monitor_info"></required>
1922 </capabilities>
1923 <parameters>
1924 <param id="thread">
1925 <jthread null="current"/>
1926 <description>
1927 The thread to query.
1928 </description>
1929 </param>
1930 <param id="owned_monitor_count_ptr">
1931 <outptr><jint/></outptr>
1932 <description>
1933 The number of monitors returned.
1934 </description>
1935 </param>
1936 <param id="owned_monitors_ptr">
1937 <allocbuf outcount="owned_monitor_count_ptr"><jobject/></allocbuf>
1938 <description>
1939 The array of owned monitors.
1940 </description>
1941 </param>
1942 </parameters>
1943 <errors>
1944 </errors>
1945 </function>
1946
1947 <function id="GetOwnedMonitorStackDepthInfo" num="153" since="1.1">
1948 <synopsis>Get Owned Monitor Stack Depth Info</synopsis>
1949 <typedef id="jvmtiMonitorStackDepthInfo"
1950 label="Monitor stack depth information structure">
1951 <field id="monitor">
1952 <jobject/>
1953 <description>
1954 The owned monitor.
1955 </description>
1956 </field>
1957 <field id="stack_depth">
1958 <jint/>
1959 <description>
1960 The stack depth. Corresponds to the stack depth used in the
1961 <internallink id="stack">Stack Frame functions</internallink>.
1962 That is, zero is the current frame, one is the frame which
1963 called the current frame. And it is negative one if the
1964 implementation cannot determine the stack depth (e.g., for
1965 monitors acquired by JNI <code>MonitorEnter</code>).
1966 </description>
1967 </field>
1968 </typedef>
1969 <description>
1970 Get information about the monitors owned by the
1971 specified thread and the depth of the stack frame which locked them.
1972 </description>
1973 <origin>new</origin>
1974 <capabilities>
1975 <required id="can_get_owned_monitor_stack_depth_info"></required>
1976 </capabilities>
1977 <parameters>
1978 <param id="thread">
1979 <jthread null="current"/>
1980 <description>
1981 The thread to query.
1982 </description>
1983 </param>
1984 <param id="monitor_info_count_ptr">
1985 <outptr><jint/></outptr>
1986 <description>
1987 The number of monitors returned.
1988 </description>
1989 </param>
1990 <param id="monitor_info_ptr">
1991 <allocbuf outcount="monitor_info_count_ptr">
1992 <struct>jvmtiMonitorStackDepthInfo</struct>
1993 </allocbuf>
1994 <description>
1995 The array of owned monitor depth information.
1996 </description>
1997 </param>
1998 </parameters>
1999 <errors>
2000 </errors>
2001 </function>
2002
2003 <function id="GetCurrentContendedMonitor" num="11">
2004 <synopsis>Get Current Contended Monitor</synopsis>
2005 <description>
2006 Get the object, if any, whose monitor the specified thread is waiting to
2007 enter or waiting to regain through <code>java.lang.Object.wait</code>.
2008 </description>
2009 <origin>jvmdi</origin>
2010 <capabilities>
2011 <required id="can_get_current_contended_monitor"></required>
2012 </capabilities>
2013 <parameters>
2014 <param id="thread">
2015 <jthread null="current"/>
2016 <description>
2017 The thread to query.
2018 </description>
2019 </param>
2020 <param id="monitor_ptr">
2021 <outptr><jobject/></outptr>
2022 <description>
2023 On return, filled with the current contended monitor, or
2024 NULL if there is none.
2025 </description>
2026 </param>
2027 </parameters>
2028 <errors>
2029 </errors>
2030 </function>
2031
2032 <callback id="jvmtiStartFunction">
2033 <void/>
2034 <synopsis>Agent Start Function</synopsis>
2035 <description>
2036 Agent supplied callback function.
2037 This function is the entry point for an agent thread
2038 started with
2039 <functionlink id="RunAgentThread"></functionlink>.
2040 </description>
2041 <parameters>
2042 <param id="jvmti_env">
2043 <outptr>
2044 <struct>jvmtiEnv</struct>
2045 </outptr>
2046 <description>
2047 The <jvmti/> environment.
2048 </description>
2049 </param>
2050 <param id="jni_env">
2051 <outptr>
2052 <struct>JNIEnv</struct>
2053 </outptr>
2054 <description>
2055 The JNI environment.
2056 </description>
2057 </param>
2058 <param id="arg">
2059 <outptr>
2060 <void/>
2061 </outptr>
2062 <description>
2063 The <code>arg</code> parameter passed to
2064 <functionlink id="RunAgentThread"></functionlink>.
2065 </description>
2066 </param>
2067 </parameters>
2068 </callback>
2069
2070 <function id="RunAgentThread" num="12">
2071 <synopsis>Run Agent Thread</synopsis>
2072 <description>
2073 Starts the execution of an agent thread. with the specified native function.
2074 The parameter <paramlink id="arg"></paramlink> is forwarded on to the
2075 <functionlink id="jvmtiStartFunction">start function</functionlink>
2076 (specified with <paramlink id="proc"></paramlink>) as its single argument.
2077 This function allows the creation of agent threads
2078 for handling communication with another process or for handling events
2079 without the need to load a special subclass of <code>java.lang.Thread</code> or
2080 implementer of <code>java.lang.Runnable</code>.
2081 Instead, the created thread can run entirely in native code.
2082 However, the created thread does require a newly created instance
2083 of <code>java.lang.Thread</code> (referenced by the argument <code>thread</code>) to
2084 which it will be associated.
2085 The thread object can be created with JNI calls.
2086 <p/>
2087 The following common thread priorities are provided for your convenience:
2088 <constants id="jvmtiThreadPriority" label="Thread Priority Constants" kind="const">
2089 <constant id="JVMTI_THREAD_MIN_PRIORITY" num="1">
2090 Minimum possible thread priority
2091 </constant>
2092 <constant id="JVMTI_THREAD_NORM_PRIORITY" num="5">
2093 Normal thread priority
2094 </constant>
2095 <constant id="JVMTI_THREAD_MAX_PRIORITY" num="10">
2096 Maximum possible thread priority
2097 </constant>
2098 </constants>
2099 <p/>
2100 The new thread is started as a daemon thread with the specified
2101 <paramlink id="priority"></paramlink>.
2102 If enabled, a <eventlink id="ThreadStart"/> event will be sent.
2103 <p/>
2104 Since the thread has been started, the thread will be live when this function
2105 returns, unless the thread has died immediately.
2106 <p/>
2107 The thread group of the thread is ignored -- specifically, the thread is not
2108 added to the thread group and the thread is not seen on queries of the thread
2109 group at either the Java programming language or <jvmti/> levels.
2110 <p/>
2111 The thread is not visible to Java programming language queries but is
2112 included in <jvmti/> queries (for example,
2113 <functionlink id="GetAllThreads"/> and
2114 <functionlink id="GetAllStackTraces"/>).
2115 <p/>
2116 Upon execution of <code>proc</code>, the new thread will be attached to the
2117 VM -- see the JNI documentation on
2118 <externallink id="jni/invocation.html#attaching-to-the-vm"
2119 >Attaching to the VM</externallink>.
2120 </description>
2121 <origin>jvmdiClone</origin>
2122 <capabilities>
2123 </capabilities>
2124 <parameters>
2125 <param id="thread">
2126 <jthread impl="noconvert" started="no"/>
2127 <description>
2128 The thread to run.
2129 </description>
2130 </param>
2131 <param id="proc">
2132 <ptrtype>
2133 <struct>jvmtiStartFunction</struct>
2134 </ptrtype>
2135 <description>
2136 The start function.
2137 </description>
2138 </param>
2139 <param id="arg">
2140 <inbuf>
2141 <void/>
2142 <nullok><code>NULL</code> is passed to the start function</nullok>
2143 </inbuf>
2144 <description>
2145 The argument to the start function.
2146 </description>
2147 </param>
2148 <param id="priority">
2149 <jint/>
2150 <description>
2151 The priority of the started thread. Any thread
2152 priority allowed by <code>java.lang.Thread.setPriority</code> can be used including
2153 those in <datalink id="jvmtiThreadPriority"></datalink>.
2154 </description>
2155 </param>
2156 </parameters>
2157 <errors>
2158 <error id="JVMTI_ERROR_INVALID_PRIORITY">
2159 <paramlink id="priority"/> is less than
2160 <datalink id="JVMTI_THREAD_MIN_PRIORITY"/>
2161 or greater than
2162 <datalink id="JVMTI_THREAD_MAX_PRIORITY"/>
2163 </error>
2164 </errors>
2165 </function>
2166
2167 <function id="SetThreadLocalStorage" jkernel="yes" impl="notrace" phase="start" num="103">
2168 <synopsis>Set Thread Local Storage</synopsis>
2169 <description>
2170 The VM stores a pointer value associated with each environment-thread
2171 pair. This pointer value is called <i>thread-local storage</i>.
2172 This value is <code>NULL</code> unless set with this function.
2173 Agents can allocate memory in which they store thread specific
2174 information. By setting thread-local storage it can then be
2175 accessed with
2176 <functionlink id="GetThreadLocalStorage"></functionlink>.
2177 <p/>
2178 This function is called by the agent to set the value of the <jvmti/>
2179 thread-local storage. <jvmti/> supplies to the agent a pointer-size
2180 thread-local storage that can be used to record per-thread
2181 information.
2182 </description>
2183 <origin>jvmpi</origin>
2184 <capabilities>
2185 </capabilities>
2186 <parameters>
2187 <param id="thread">
2188 <jthread null="current"/>
2189 <description>
2190 Store to this thread.
2191 </description>
2192 </param>
2193 <param id="data">
2194 <inbuf>
2195 <void/>
2196 <nullok>value is set to <code>NULL</code></nullok>
2197 </inbuf>
2198 <description>
2199 The value to be entered into the thread-local storage.
2200 </description>
2201 </param>
2202 </parameters>
2203 <errors>
2204 </errors>
2205 </function>
2206
2207 <function id="GetThreadLocalStorage" jkernel="yes" impl="innative notrace" phase="start" num="102">
2208 <synopsis>Get Thread Local Storage</synopsis>
2209 <description>
2210 Called by the agent to get the value of the <jvmti/> thread-local
2211 storage.
2212 </description>
2213 <origin>jvmpi</origin>
2214 <capabilities>
2215 </capabilities>
2216 <parameters>
2217 <param id="thread">
2218 <jthread null="current" impl="noconvert"/>
2219 <description>
2220 Retrieve from this thread.
2221 </description>
2222 </param>
2223 <param id="data_ptr">
2224 <agentbuf><void/></agentbuf>
2225 <description>
2226 Pointer through which the value of the thread local
2227 storage is returned.
2228 If thread-local storage has not been set with
2229 <functionlink id="SetThreadLocalStorage"></functionlink> the returned
2230 pointer is <code>NULL</code>.
2231 </description>
2232 </param>
2233 </parameters>
2234 <errors>
2235 </errors>
2236 </function>
2237
2238 </category>
2239
2240 <category id="thread_groups" label="Thread Group">
2241 <intro>
2242 </intro>
2243
2244 <function id="GetTopThreadGroups" num="13">
2245 <synopsis>Get Top Thread Groups</synopsis>
2246 <description>
2247 Return all top-level (parentless) thread groups in the VM.
2248 </description>
2249 <origin>jvmdi</origin>
2250 <capabilities>
2251 </capabilities>
2252 <parameters>
2253 <param id="group_count_ptr">
2254 <outptr><jint/></outptr>
2255 <description>
2256 On return, points to the number of top-level thread groups.
2257 </description>
2258 </param>
2259 <param id="groups_ptr">
2260 <allocbuf outcount="group_count_ptr"><jthreadGroup/></allocbuf>
2261 <description>
2262 On return, refers to a pointer to the top-level thread group array.
2263 </description>
2264 </param>
2265 </parameters>
2266 <errors>
2267 </errors>
2268 </function>
2269
2270 <function id="GetThreadGroupInfo" num="14">
2271 <synopsis>Get Thread Group Info</synopsis>
2272 <typedef id="jvmtiThreadGroupInfo" label="Thread group information structure">
2273 <field id="parent">
2274 <jthreadGroup/>
2275 <description>
2276 The parent thread group.
2277 </description>
2278 </field>
2279 <field id="name">
2280 <allocfieldbuf><char/></allocfieldbuf>
2281 <description>
2282 The thread group's name, encoded as a
2283 <internallink id="mUTF">modified UTF-8</internallink> string.
2284 </description>
2285 </field>
2286 <field id="max_priority">
2287 <jint/>
2288 <description>
2289 The maximum priority for this thread group.
2290 </description>
2291 </field>
2292 <field id="is_daemon">
2293 <jboolean/>
2294 <description>
2295 Is this a daemon thread group?
2296 </description>
2297 </field>
2298 </typedef>
2299 <description>
2300 Get information about the thread group. The fields of the
2301 <functionlink id="jvmtiThreadGroupInfo"></functionlink> structure
2302 are filled in with details of the specified thread group.
2303 </description>
2304 <origin>jvmdi</origin>
2305 <capabilities>
2306 </capabilities>
2307 <parameters>
2308 <param id="group">
2309 <jthreadGroup/>
2310 <description>
2311 The thread group to query.
2312 </description>
2313 </param>
2314 <param id="info_ptr">
2315 <outptr><struct>jvmtiThreadGroupInfo</struct></outptr>
2316 <description>
2317 On return, filled with information describing the specified
2318 thread group.
2319 </description>
2320 </param>
2321 </parameters>
2322 <errors>
2323 </errors>
2324 </function>
2325
2326 <function id="GetThreadGroupChildren" num="15">
2327 <synopsis>Get Thread Group Children</synopsis>
2328 <description>
2329 Get the live threads and active subgroups in this thread group.
2330 </description>
2331 <origin>jvmdi</origin>
2332 <capabilities>
2333 </capabilities>
2334 <parameters>
2335 <param id="group">
2336 <jthreadGroup/>
2337 <description>
2338 The group to query.
2339 </description>
2340 </param>
2341 <param id="thread_count_ptr">
2342 <outptr><jint/></outptr>
2343 <description>
2344 On return, points to the number of live threads in this thread group.
2345 </description>
2346 </param>
2347 <param id="threads_ptr">
2348 <allocbuf outcount="thread_count_ptr"><jthread/></allocbuf>
2349 <description>
2350 On return, points to an array of the live threads in this thread group.
2351 </description>
2352 </param>
2353 <param id="group_count_ptr">
2354 <outptr><jint/></outptr>
2355 <description>
2356 On return, points to the number of active child thread groups
2357 </description>
2358 </param>
2359 <param id="groups_ptr">
2360 <allocbuf outcount="group_count_ptr"><jthreadGroup/></allocbuf>
2361 <description>
2362 On return, points to an array of the active child thread groups.
2363 </description>
2364 </param>
2365 </parameters>
2366 <errors>
2367 </errors>
2368 </function>
2369 </category>
2370
2371 <category id="stack" label="Stack Frame">
2372 <intro>
2373 These functions provide information about the stack of a thread.
2374 Stack frames are referenced by depth.
2375 The frame at depth zero is the current frame.
2376 <p/>
2377 Stack frames are as described in
2378 <vmspec chapter="3.6"/>,
2379 That is, they correspond to method
2380 invocations (including native methods) but do not correspond to platform native or
2381 VM internal frames.
2382 <p/>
2383 A <jvmti/> implementation may use method invocations to launch a thread and
2384 the corresponding frames may be included in the stack as presented by these functions --
2385 that is, there may be frames shown
2386 deeper than <code>main()</code> and <code>run()</code>.
2387 However this presentation must be consistent across all <jvmti/> functionality which
2388 uses stack frames or stack depth.
2389 </intro>
2390
2391 <typedef id="jvmtiFrameInfo" label="Stack frame information structure">
2392 <description>
2393 Information about a stack frame is returned in this structure.
2394 </description>
2395 <field id="method">
2396 <jmethodID/>
2397 <description>
2398 The method executing in this frame.
2399 </description>
2400 </field>
2401 <field id="location">
2402 <jlocation/>
2403 <description>
2404 The index of the instruction executing in this frame.
2405 <code>-1</code> if the frame is executing a native method.
2406 </description>
2407 </field>
2408 </typedef>
2409
2410 <typedef id="jvmtiStackInfo" label="Stack information structure">
2411 <description>
2412 Information about a set of stack frames is returned in this structure.
2413 </description>
2414 <field id="thread">
2415 <jthread/>
2416 <description>
2417 On return, the thread traced.
2418 </description>
2419 </field>
2420 <field id="state">
2421 <jint/>
2422 <description>
2423 On return, the thread state. See <functionlink id="GetThreadState"></functionlink>.
2424 </description>
2425 </field>
2426 <field id="frame_buffer">
2427 <outbuf incount="max_frame_count">
2428 <struct>jvmtiFrameInfo</struct>
2429 </outbuf>
2430 <description>
2431 On return, this agent allocated buffer is filled
2432 with stack frame information.
2433 </description>
2434 </field>
2435 <field id="frame_count">
2436 <jint/>
2437 <description>
2438 On return, the number of records filled into
2439 <code>frame_buffer</code>.
2440 This will be
2441 min(<code>max_frame_count</code>, <i>stackDepth</i>).
2442 </description>
2443 </field>
2444 </typedef>
2445
2446 <function id="GetStackTrace" num="104">
2447 <synopsis>Get Stack Trace</synopsis>
2448 <description>
2449 Get information about the stack of a thread.
2450 If <paramlink id="max_frame_count"></paramlink> is less than the depth of the stack,
2451 the <paramlink id="max_frame_count"></paramlink> topmost frames are returned,
2452 otherwise the entire stack is returned.
2453 The topmost frames, those most recently invoked, are at the beginning of the returned buffer.
2454 <p/>
2455 The following example causes up to five of the topmost frames
2456 to be returned and (if there are any frames) the currently
2457 executing method name to be printed.
2458 <example>
2459 jvmtiFrameInfo frames[5];
2460 jint count;
2461 jvmtiError err;
2462
2463 err = (*jvmti)->GetStackTrace(jvmti, aThread, 0, 5,
2464 frames, &count);
2465 if (err == JVMTI_ERROR_NONE && count >= 1) {
2466 char *methodName;
2467 err = (*jvmti)->GetMethodName(jvmti, frames[0].method,
2468 &methodName, NULL, NULL);
2469 if (err == JVMTI_ERROR_NONE) {
2470 printf("Executing method: %s", methodName);
2471 }
2472 }
2473 </example>
2474 <todo>
2475 check example code.
2476 </todo>
2477 <p/>
2478 The <paramlink id="thread"></paramlink> need not be suspended
2479 to call this function.
2480 <p/>
2481 The <functionlink id="GetLineNumberTable"></functionlink>
2482 function can be used to map locations to line numbers. Note that
2483 this mapping can be done lazily.
2484 </description>
2485 <origin>jvmpi</origin>
2486 <capabilities>
2487 </capabilities>
2488 <parameters>
2489 <param id="thread">
2490 <jthread null="current"/>
2491 <description>
2492 Fetch the stack trace of this thread.
2493 </description>
2494 </param>
2495 <param id="start_depth">
2496 <jint/>
2497 <description>
2498 Begin retrieving frames at this depth.
2499 If non-negative, count from the current frame,
2500 the first frame retrieved is at depth <code>start_depth</code>.
2501 For example, if zero, start from the current frame; if one, start from the
2502 caller of the current frame; if two, start from the caller of the
2503 caller of the current frame; and so on.
2504 If negative, count from below the oldest frame,
2505 the first frame retrieved is at depth <i>stackDepth</i><code> + start_depth</code>,
2506 where <i>stackDepth</i> is the count of frames on the stack.
2507 For example, if negative one, only the oldest frame is retrieved;
2508 if negative two, start from the frame called by the oldest frame.
2509 </description>
2510 </param>
2511 <param id="max_frame_count">
2512 <jint min="0"/>
2513 <description>
2514 The maximum number of <datalink id="jvmtiFrameInfo"/> records to retrieve.
2515 </description>
2516 </param>
2517 <param id="frame_buffer">
2518 <outbuf incount="max_frame_count" outcount="count_ptr">
2519 <struct>jvmtiFrameInfo</struct>
2520 </outbuf>
2521 <description>
2522 On return, this agent allocated buffer is filled
2523 with stack frame information.
2524 </description>
2525 </param>
2526 <param id="count_ptr">
2527 <outptr><jint/></outptr>
2528 <description>
2529 On return, points to the number of records filled in.
2530 For non-negative <code>start_depth</code>, this will be
2531 min(<code>max_frame_count</code>, <i>stackDepth</i><code> - start_depth</code>).
2532 For negative <code>start_depth</code>, this will be
2533 min(<code>max_frame_count</code>, <code>-start_depth</code>).
2534 </description>
2535 </param>
2536 </parameters>
2537 <errors>
2538 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
2539 <paramlink id="start_depth"/> is positive and greater than or equal to <i>stackDepth</i>.
2540 Or <paramlink id="start_depth"/> is negative and less than <i>-stackDepth</i>.
2541 </error>
2542 </errors>
2543 </function>
2544
2545
2546 <function id="GetAllStackTraces" num="100">
2547 <synopsis>Get All Stack Traces</synopsis>
2548 <description>
2549 Get information about the stacks of all live threads
2550 (including <internallink id="RunAgentThread">agent threads</internallink>).
2551 If <paramlink id="max_frame_count"/> is less than the depth of a stack,
2552 the <paramlink id="max_frame_count"/> topmost frames are returned for that thread,
2553 otherwise the entire stack is returned.
2554 The topmost frames, those most recently invoked, are at the beginning of the returned buffer.
2555 <p/>
2556 All stacks are collected simultaneously, that is, no changes will occur to the
2557 thread state or stacks between the sampling of one thread and the next.
2558 The threads need not be suspended.
2559
2560 <example>
2561 jvmtiStackInfo *stack_info;
2562 jint thread_count;
2563 int ti;
2564 jvmtiError err;
2565
2566 err = (*jvmti)->GetAllStackTraces(jvmti, MAX_FRAMES, &stack_info, &thread_count);
2567 if (err != JVMTI_ERROR_NONE) {
2568 ...
2569 }
2570 for (ti = 0; ti < thread_count; ++ti) {
2571 jvmtiStackInfo *infop = &stack_info[ti];
2572 jthread thread = infop->thread;
2573 jint state = infop->state;
2574 jvmtiFrameInfo *frames = infop->frame_buffer;
2575 int fi;
2576
2577 myThreadAndStatePrinter(thread, state);
2578 for (fi = 0; fi < infop->frame_count; fi++) {
2579 myFramePrinter(frames[fi].method, frames[fi].location);
2580 }
2581 }
2582 /* this one Deallocate call frees all data allocated by GetAllStackTraces */
2583 err = (*jvmti)->Deallocate(jvmti, stack_info);
2584 </example>
2585 <todo>
2586 check example code.
2587 </todo>
2588
2589 </description>
2590 <origin>new</origin>
2591 <capabilities>
2592 </capabilities>
2593 <parameters>
2594 <param id="max_frame_count">
2595 <jint min="0"/>
2596 <description>
2597 The maximum number of <datalink id="jvmtiFrameInfo"/> records to retrieve per thread.
2598 </description>
2599 </param>
2600 <param id="stack_info_ptr">
2601 <allocbuf>
2602 <struct>jvmtiStackInfo</struct>
2603 </allocbuf>
2604 <description>
2605 On return, this buffer is filled
2606 with stack information for each thread.
2607 The number of <datalink id="jvmtiStackInfo"/> records is determined
2608 by <paramlink id="thread_count_ptr"/>.
2609 <p/>
2610 Note that this buffer is allocated to include the <datalink id="jvmtiFrameInfo"/>
2611 buffers pointed to by <datalink id="jvmtiStackInfo.frame_buffer"/>.
2612 These buffers must not be separately deallocated.
2613 </description>
2614 </param>
2615 <param id="thread_count_ptr">
2616 <outptr><jint/></outptr>
2617 <description>
2618 The number of threads traced.
2619 </description>
2620 </param>
2621 </parameters>
2622 <errors>
2623 </errors>
2624 </function>
2625
2626 <function id="GetThreadListStackTraces" num="101">
2627 <synopsis>Get Thread List Stack Traces</synopsis>
2628 <description>
2629 Get information about the stacks of the supplied threads.
2630 If <paramlink id="max_frame_count"/> is less than the depth of a stack,
2631 the <paramlink id="max_frame_count"/> topmost frames are returned for that thread,
2632 otherwise the entire stack is returned.
2633 The topmost frames, those most recently invoked, are at the beginning of the returned buffer.
2634 <p/>
2635 All stacks are collected simultaneously, that is, no changes will occur to the
2636 thread state or stacks between the sampling one thread and the next.
2637 The threads need not be suspended.
2638 <p/>
2639 If a thread has not yet started or terminates before the stack information is collected,
2640 a zero length stack (<datalink id="jvmtiStackInfo.frame_count"/> will be zero)
2641 will be returned and the thread <datalink id="jvmtiStackInfo.state"/> can be checked.
2642 <p/>
2643 See the example for the similar function
2644 <functionlink id="GetAllStackTraces"/>.
2645 </description>
2646 <origin>new</origin>
2647 <capabilities>
2648 </capabilities>
2649 <parameters>
2650 <param id="thread_count">
2651 <jint min="0"/>
2652 <description>
2653 The number of threads to trace.
2654 </description>
2655 </param>
2656 <param id="thread_list">
2657 <inbuf incount="thread_count"><jthread/></inbuf>
2658 <description>
2659 The list of threads to trace.
2660 </description>
2661 </param>
2662 <param id="max_frame_count">
2663 <jint min="0"/>
2664 <description>
2665 The maximum number of <datalink id="jvmtiFrameInfo"/> records to retrieve per thread.
2666 </description>
2667 </param>
2668 <param id="stack_info_ptr">
2669 <allocbuf outcount="thread_count">
2670 <struct>jvmtiStackInfo</struct>
2671 </allocbuf>
2672 <description>
2673 On return, this buffer is filled
2674 with stack information for each thread.
2675 The number of <datalink id="jvmtiStackInfo"/> records is determined
2676 by <paramlink id="thread_count"/>.
2677 <p/>
2678 Note that this buffer is allocated to include the <datalink id="jvmtiFrameInfo"/>
2679 buffers pointed to by <datalink id="jvmtiStackInfo.frame_buffer"/>.
2680 These buffers must not be separately deallocated.
2681 </description>
2682 </param>
2683 </parameters>
2684 <errors>
2685 <error id="JVMTI_ERROR_INVALID_THREAD">
2686 An element in <paramlink id="thread_list"/> is not a thread object.
2687 </error>
2688 </errors>
2689 </function>
2690
2691 <elide>
2692 <function id="AsyncGetStackTrace" num="1000">
2693 <synopsis>Get Stack Trace--Asynchronous</synopsis>
2694 <description>
2695 Get information about the entire stack of a thread (or a sub-section of it).
2696 This is the asynchronous version of <functionlink id="GetStackTrace"></functionlink>
2697 and is reentrant and safe to call
2698 from asynchronous signal handlers.
2699 The stack trace is returned only for the calling thread.
2700 <p/>
2701 The <functionlink id="GetLineNumberTable"></functionlink>
2702 function can be used to map locations to line numbers. Note that
2703 this mapping can be done lazily.
2704 </description>
2705 <origin>jvmpi</origin>
2706 <capabilities>
2707 <required id="can_get_async_stack_trace"></required>
2708 <capability id="can_show_JVM_spec_async_frames">
2709 If <code>false</code>,
2710 <paramlink id="use_java_stack"></paramlink>
2711 must be <code>false</code>.
2712 </capability>
2713 </capabilities>
2714 <parameters>
2715 <param id="use_java_stack">
2716 <jboolean/>
2717 <description>
2718 Return the stack showing <vmspec/>
2719 model of the stack;
2720 otherwise, show the internal representation of the stack with
2721 inlined and optimized methods missing. If the virtual machine
2722 is using the <i>Java Virtual Machine Specification</i> stack model
2723 internally, this flag is ignored.
2724 </description>
2725 </param>
2726 <param id="max_count">
2727 <jint min="0"/>
2728 <description>
2729 The maximum number of <datalink id="jvmtiFrameInfo"/> records to retrieve.
2730 Retrieve this many unless the stack depth is less than <code>max_count</code>.
2731 </description>
2732 </param>
2733 <param id="frame_buffer">
2734 <outbuf incount="max_count" outcount="count_ptr">
2735 <struct>jvmtiFrameInfo</struct>
2736 <nullok>this information is not returned</nullok>
2737 </outbuf>
2738 <description>
2739 The agent passes in a buffer
2740 large enough to hold <code>max_count</code> records of
2741 <datalink id="jvmtiFrameInfo"></datalink>. This buffer must be
2742 pre-allocated by the agent.
2743 </description>
2744 </param>
2745 <param id="count_ptr">
2746 <outptr><jint/></outptr>
2747 <description>
2748 On return, points to the number of records filled in..
2749 </description>
2750 </param>
2751 </parameters>
2752 <errors>
2753 <error id="JVMTI_ERROR_UNATTACHED_THREAD">
2754 The thread being used to call this function is not attached
2755 to the virtual machine. Calls must be made from attached threads.
2756 </error>
2757 </errors>
2758 </function>
2759 </elide>
2760
2761 <function id="GetFrameCount" num="16">
2762 <synopsis>Get Frame Count</synopsis>
2763 <description>
2764 Get the number of frames currently in the specified thread's call stack.
2765 <p/>
2766 If this function is called for a thread actively executing bytecodes (for example,
2767 not the current thread and not suspended), the information returned is transient.
2768 </description>
2769 <origin>jvmdi</origin>
2770 <capabilities>
2771 </capabilities>
2772 <parameters>
2773 <param id="thread">
2774 <jthread null="current"/>
2775 <description>
2776 The thread to query.
2777 </description>
2778 </param>
2779 <param id="count_ptr">
2780 <outptr><jint/></outptr>
2781 <description>
2782 On return, points to the number of frames in the call stack.
2783 </description>
2784 </param>
2785 </parameters>
2786 <errors>
2787 </errors>
2788 </function>
2789
2790 <function id="PopFrame" num="80">
2791 <synopsis>Pop Frame</synopsis>
2792 <description>
2793 Pop the current frame of <code>thread</code>'s stack.
2794 Popping a frame takes you to the previous frame.
2795 When the thread is resumed, the execution
2796 state of the thread is reset to the state
2797 immediately before the called method was invoked.
2798 That is (using <vmspec/> terminology):
2799 <ul>
2800 <li>the current frame is discarded as the previous frame becomes the current one</li>
2801 <li>the operand stack is restored--the argument values are added back
2802 and if the invoke was not <code>invokestatic</code>,
2803 <code>objectref</code> is added back as well</li>
2804 <li>the Java virtual machine PC is restored to the opcode
2805 of the invoke instruction</li>
2806 </ul>
2807 Note however, that any changes to the arguments, which
2808 occurred in the called method, remain;
2809 when execution continues, the first instruction to
2810 execute will be the invoke.
2811 <p/>
2812 Between calling <code>PopFrame</code> and resuming the
2813 thread the state of the stack is undefined.
2814 To pop frames beyond the first,
2815 these three steps must be repeated:
2816 <ul>
2817 <li>suspend the thread via an event (step, breakpoint, ...)</li>
2818 <li>call <code>PopFrame</code></li>
2819 <li>resume the thread</li>
2820 </ul>
2821 <p/>
2822 A lock acquired by calling the called method
2823 (if it is a <code>synchronized</code> method)
2824 and locks acquired by entering <code>synchronized</code>
2825 blocks within the called method are released.
2826 Note: this does not apply to native locks or
2827 <code>java.util.concurrent.locks</code> locks.
2828 <p/>
2829 Finally blocks are not executed.
2830 <p/>
2831 Changes to global state are not addressed and thus remain changed.
2832 <p/>
2833 The specified thread must be suspended (which implies it cannot be the current thread).
2834 <p/>
2835 Both the called method and calling method must be non-native Java programming
2836 language methods.
2837 <p/>
2838 No <jvmti/> events are generated by this function.
2839 </description>
2840 <origin>jvmdi</origin>
2841 <capabilities>
2842 <required id="can_pop_frame"></required>
2843 </capabilities>
2844 <parameters>
2845 <param id="thread">
2846 <jthread/>
2847 <description>
2848 The thread whose current frame is to be popped.
2849 </description>
2850 </param>
2851 </parameters>
2852 <errors>
2853 <error id="JVMTI_ERROR_OPAQUE_FRAME">
2854 Called or calling method is a native method.
2855 The implementation is unable to pop this frame.
2856 </error>
2857 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
2858 Thread was not suspended.
2859 </error>
2860 <error id="JVMTI_ERROR_NO_MORE_FRAMES">
2861 There are less than two stack frames on the call stack.
2862 </error>
2863 </errors>
2864 </function>
2865
2866 <function id="GetFrameLocation" num="19">
2867 <synopsis>Get Frame Location</synopsis>
2868 <description>
2869 <p/>
2870 For a Java programming language frame, return the location of the instruction
2871 currently executing.
2872 </description>
2873 <origin>jvmdiClone</origin>
2874 <capabilities>
2875 </capabilities>
2876 <parameters>
2877 <param id="thread">
2878 <jthread null="current" frame="frame"/>
2879 <description>
2880 The thread of the frame to query.
2881 </description>
2882 </param>
2883 <param id="depth">
2884 <jframeID thread="thread"/>
2885 <description>
2886 The depth of the frame to query.
2887 </description>
2888 </param>
2889 <param id="method_ptr">
2890 <outptr><jmethodID/></outptr>
2891 <description>
2892 On return, points to the method for the current location.
2893 </description>
2894 </param>
2895 <param id="location_ptr">
2896 <outptr><jlocation/></outptr>
2897 <description>
2898 On return, points to the index of the currently
2899 executing instruction.
2900 Is set to <code>-1</code> if the frame is executing
2901 a native method.
2902 </description>
2903 </param>
2904 </parameters>
2905 <errors>
2906 </errors>
2907 </function>
2908
2909 <function id="NotifyFramePop" num="20">
2910 <synopsis>Notify Frame Pop</synopsis>
2911 <description>
2912 When the frame that is currently at <paramlink id="depth"></paramlink>
2913 is popped from the stack, generate a
2914 <eventlink id="FramePop"></eventlink> event. See the
2915 <eventlink id="FramePop"></eventlink> event for details.
2916 Only frames corresponding to non-native Java programming language
2917 methods can receive notification.
2918 <p/>
2919 The specified thread must either be the current thread
2920 or the thread must be suspended.
2921 </description>
2922 <origin>jvmdi</origin>
2923 <capabilities>
2924 <required id="can_generate_frame_pop_events"></required>
2925 </capabilities>
2926 <parameters>
2927 <param id="thread">
2928 <jthread null="current" frame="depth"/>
2929 <description>
2930 The thread of the frame for which the frame pop event will be generated.
2931 </description>
2932 </param>
2933 <param id="depth">
2934 <jframeID thread="thread"/>
2935 <description>
2936 The depth of the frame for which the frame pop event will be generated.
2937 </description>
2938 </param>
2939 </parameters>
2940 <errors>
2941 <error id="JVMTI_ERROR_OPAQUE_FRAME">
2942 The frame at <code>depth</code> is executing a
2943 native method.
2944 </error>
2945 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
2946 Thread was not suspended and was not the current thread.
2947 </error>
2948 </errors>
2949 </function>
2950
2951 </category>
2952
2953 <category id="ForceEarlyReturn" label="Force Early Return">
2954 <intro>
2955 These functions allow an agent to force a method
2956 to return at any point during its execution.
2957 The method which will return early is referred to as the <i>called method</i>.
2958 The called method is the current method
2959 (as defined by
2960 <vmspec chapter="3.6"/>)
2961 for the specified thread at
2962 the time the function is called.
2963 <p/>
2964 The specified thread must be suspended or must be the current thread.
2965 The return occurs when execution of Java programming
2966 language code is resumed on this thread.
2967 Between calling one of these functions and resumption
2968 of thread execution, the state of the stack is undefined.
2969 <p/>
2970 No further instructions are executed in the called method.
2971 Specifically, finally blocks are not executed.
2972 Note: this can cause inconsistent states in the application.
2973 <p/>
2974 A lock acquired by calling the called method
2975 (if it is a <code>synchronized</code> method)
2976 and locks acquired by entering <code>synchronized</code>
2977 blocks within the called method are released.
2978 Note: this does not apply to native locks or
2979 <code>java.util.concurrent.locks</code> locks.
2980 <p/>
2981 Events, such as <eventlink id="MethodExit"></eventlink>,
2982 are generated as they would be in a normal return.
2983 <p/>
2984 The called method must be a non-native Java programming
2985 language method.
2986 Forcing return on a thread with only one frame on the
2987 stack causes the thread to exit when resumed.
2988 </intro>
2989
2990 <function id="ForceEarlyReturnObject" num="81" since="1.1">
2991 <synopsis>Force Early Return - Object</synopsis>
2992 <description>
2993 This function can be used to return from a method whose
2994 result type is <code>Object</code>
2995 or a subclass of <code>Object</code>.
2996 </description>
2997 <origin>new</origin>
2998 <capabilities>
2999 <required id="can_force_early_return"></required>
3000 </capabilities>
3001 <parameters>
3002 <param id="thread">
3003 <jthread null="current"/>
3004 <description>
3005 The thread whose current frame is to return early.
3006 </description>
3007 </param>
3008 <param id="value">
3009 <jobject/>
3010 <description>
3011 The return value for the called frame.
3012 An object or <code>NULL</code>.
3013 </description>
3014 </param>
3015 </parameters>
3016 <errors>
3017 <error id="JVMTI_ERROR_OPAQUE_FRAME">
3018 Attempted to return early from a frame
3019 corresponding to a native method.
3020 Or the implementation is unable to provide
3021 this functionality on this frame.
3022 </error>
3023 <error id="JVMTI_ERROR_TYPE_MISMATCH">
3024 The result type of the called method is not
3025 <code>Object</code> or a subclass of <code>Object</code>.
3026 </error>
3027 <error id="JVMTI_ERROR_TYPE_MISMATCH">
3028 The supplied <paramlink id="value"/> is not compatible with the
3029 result type of the called method.
3030 </error>
3031 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
3032 Thread was not the current thread and was not suspended.
3033 </error>
3034 <error id="JVMTI_ERROR_NO_MORE_FRAMES">
3035 There are no more frames on the call stack.
3036 </error>
3037 </errors>
3038 </function>
3039
3040 <function id="ForceEarlyReturnInt" num="82" since="1.1">
3041 <synopsis>Force Early Return - Int</synopsis>
3042 <description>
3043 This function can be used to return from a method whose
3044 result type is <code>int</code>, <code>short</code>,
3045 <code>char</code>, <code>byte</code>, or
3046 <code>boolean</code>.
3047 </description>
3048 <origin>new</origin>
3049 <capabilities>
3050 <required id="can_force_early_return"></required>
3051 </capabilities>
3052 <parameters>
3053 <param id="thread">
3054 <jthread null="current"/>
3055 <description>
3056 The thread whose current frame is to return early.
3057 </description>
3058 </param>
3059 <param id="value">
3060 <jint/>
3061 <description>
3062 The return value for the called frame.
3063 </description>
3064 </param>
3065 </parameters>
3066 <errors>
3067 <error id="JVMTI_ERROR_OPAQUE_FRAME">
3068 Attempted to return early from a frame
3069 corresponding to a native method.
3070 Or the implementation is unable to provide
3071 this functionality on this frame.
3072 </error>
3073 <error id="JVMTI_ERROR_TYPE_MISMATCH">
3074 The result type of the called method is not
3075 <code>int</code>, <code>short</code>,
3076 <code>char</code>, <code>byte</code>, or
3077 <code>boolean</code>.
3078 </error>
3079 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
3080 Thread was not the current thread and was not suspended.
3081 </error>
3082 <error id="JVMTI_ERROR_NO_MORE_FRAMES">
3083 There are no frames on the call stack.
3084 </error>
3085 </errors>
3086 </function>
3087
3088 <function id="ForceEarlyReturnLong" num="83" since="1.1">
3089 <synopsis>Force Early Return - Long</synopsis>
3090 <description>
3091 This function can be used to return from a method whose
3092 result type is <code>long</code>.
3093 </description>
3094 <origin>new</origin>
3095 <capabilities>
3096 <required id="can_force_early_return"></required>
3097 </capabilities>
3098 <parameters>
3099 <param id="thread">
3100 <jthread null="current"/>
3101 <description>
3102 The thread whose current frame is to return early.
3103 </description>
3104 </param>
3105 <param id="value">
3106 <jlong/>
3107 <description>
3108 The return value for the called frame.
3109 </description>
3110 </param>
3111 </parameters>
3112 <errors>
3113 <error id="JVMTI_ERROR_OPAQUE_FRAME">
3114 Attempted to return early from a frame
3115 corresponding to a native method.
3116 Or the implementation is unable to provide
3117 this functionality on this frame.
3118 </error>
3119 <error id="JVMTI_ERROR_TYPE_MISMATCH">
3120 The result type of the called method is not <code>long</code>.
3121 </error>
3122 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
3123 Thread was not the current thread and was not suspended.
3124 </error>
3125 <error id="JVMTI_ERROR_NO_MORE_FRAMES">
3126 There are no frames on the call stack.
3127 </error>
3128 </errors>
3129 </function>
3130
3131 <function id="ForceEarlyReturnFloat" num="84" since="1.1">
3132 <synopsis>Force Early Return - Float</synopsis>
3133 <description>
3134 This function can be used to return from a method whose
3135 result type is <code>float</code>.
3136 </description>
3137 <origin>new</origin>
3138 <capabilities>
3139 <required id="can_force_early_return"></required>
3140 </capabilities>
3141 <parameters>
3142 <param id="thread">
3143 <jthread null="current"/>
3144 <description>
3145 The thread whose current frame is to return early.
3146 </description>
3147 </param>
3148 <param id="value">
3149 <jfloat/>
3150 <description>
3151 The return value for the called frame.
3152 </description>
3153 </param>
3154 </parameters>
3155 <errors>
3156 <error id="JVMTI_ERROR_OPAQUE_FRAME">
3157 Attempted to return early from a frame
3158 corresponding to a native method.
3159 Or the implementation is unable to provide
3160 this functionality on this frame.
3161 </error>
3162 <error id="JVMTI_ERROR_TYPE_MISMATCH">
3163 The result type of the called method is not <code>float</code>.
3164 </error>
3165 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
3166 Thread was not the current thread and was not suspended.
3167 </error>
3168 <error id="JVMTI_ERROR_NO_MORE_FRAMES">
3169 There are no frames on the call stack.
3170 </error>
3171 </errors>
3172 </function>
3173
3174 <function id="ForceEarlyReturnDouble" num="85" since="1.1">
3175 <synopsis>Force Early Return - Double</synopsis>
3176 <description>
3177 This function can be used to return from a method whose
3178 result type is <code>double</code>.
3179 </description>
3180 <origin>new</origin>
3181 <capabilities>
3182 <required id="can_force_early_return"></required>
3183 </capabilities>
3184 <parameters>
3185 <param id="thread">
3186 <jthread null="current"/>
3187 <description>
3188 The thread whose current frame is to return early.
3189 </description>
3190 </param>
3191 <param id="value">
3192 <jdouble/>
3193 <description>
3194 The return value for the called frame.
3195 </description>
3196 </param>
3197 </parameters>
3198 <errors>
3199 <error id="JVMTI_ERROR_OPAQUE_FRAME">
3200 Attempted to return early from a frame corresponding to a native method.
3201 Or the implementation is unable to provide this functionality on this frame.
3202 </error>
3203 <error id="JVMTI_ERROR_TYPE_MISMATCH">
3204 The result type of the called method is not <code>double</code>.
3205 </error>
3206 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
3207 Thread was not the current thread and was not suspended.
3208 </error>
3209 <error id="JVMTI_ERROR_NO_MORE_FRAMES">
3210 There are no frames on the call stack.
3211 </error>
3212 </errors>
3213 </function>
3214
3215 <function id="ForceEarlyReturnVoid" num="86" since="1.1">
3216 <synopsis>Force Early Return - Void</synopsis>
3217 <description>
3218 This function can be used to return from a method with no result type.
3219 That is, the called method must be declared <code>void</code>.
3220 </description>
3221 <origin>new</origin>
3222 <capabilities>
3223 <required id="can_force_early_return"></required>
3224 </capabilities>
3225 <parameters>
3226 <param id="thread">
3227 <jthread null="current"/>
3228 <description>
3229 The thread whose current frame is to return early.
3230 </description>
3231 </param>
3232 </parameters>
3233 <errors>
3234 <error id="JVMTI_ERROR_OPAQUE_FRAME">
3235 Attempted to return early from a frame
3236 corresponding to a native method.
3237 Or the implementation is unable to provide
3238 this functionality on this frame.
3239 </error>
3240 <error id="JVMTI_ERROR_TYPE_MISMATCH">
3241 The called method has a result type.
3242 </error>
3243 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
3244 Thread was not the current thread and was not suspended.
3245 </error>
3246 <error id="JVMTI_ERROR_NO_MORE_FRAMES">
3247 There are no frames on the call stack.
3248 </error>
3249 </errors>
3250 </function>
3251
3252 </category>
3253
3254 <category id="Heap" label="Heap">
3255 <intro>
3256 These functions are used to analyze the heap.
3257 Functionality includes the ability to view the objects in the
3258 heap and to tag these objects.
3259 </intro>
3260
3261 <intro id="objectTags" label="Object Tags">
3262 A <i>tag</i> is a value associated with an object.
3263 Tags are explicitly set by the agent using the
3264 <functionlink id="SetTag"></functionlink> function or by
3265 callback functions such as <functionlink id="jvmtiHeapIterationCallback"/>.
3266 <p/>
3267 Tags are local to the environment; that is, the tags of one
3268 environment are not visible in another.
3269 <p/>
3270 Tags are <code>jlong</code> values which can be used
3271 simply to mark an object or to store a pointer to more detailed
3272 information. Objects which have not been tagged have a
3273 tag of zero.
3274 Setting a tag to zero makes the object untagged.
3275 </intro>
3276
3277 <intro id="heapCallbacks" label="Heap Callback Functions">
3278 Heap functions which iterate through the heap and recursively
3279 follow object references use agent supplied callback functions
3280 to deliver the information.
3281 <p/>
3282 These heap callback functions must adhere to the following restrictions --
3283 These callbacks must not use JNI functions.
3284 These callbacks must not use <jvmti/> functions except
3285 <i>callback safe</i> functions which
3286 specifically allow such use (see the raw monitor, memory management,
3287 and environment local storage functions).
3288 <p/>
3289 An implementation may invoke a callback on an internal thread or
3290 the thread which called the iteration function.
3291 Heap callbacks are single threaded -- no more than one callback will
3292 be invoked at a time.
3293 <p/>
3294 The Heap Filter Flags can be used to prevent reporting
3295 based on the tag status of an object or its class.
3296 If no flags are set (the <code>jint</code> is zero), objects
3297 will not be filtered out.
3298
3299 <constants id="jvmtiHeapFilter" label="Heap Filter Flags" kind="bits">
3300 <constant id="JVMTI_HEAP_FILTER_TAGGED" num="0x4">
3301 Filter out tagged objects. Objects which are tagged are not included.
3302 </constant>
3303 <constant id="JVMTI_HEAP_FILTER_UNTAGGED" num="0x8">
3304 Filter out untagged objects. Objects which are not tagged are not included.
3305 </constant>
3306 <constant id="JVMTI_HEAP_FILTER_CLASS_TAGGED" num="0x10">
3307 Filter out objects with tagged classes. Objects whose class is tagged are not included.
3308 </constant>
3309 <constant id="JVMTI_HEAP_FILTER_CLASS_UNTAGGED" num="0x20">
3310 Filter out objects with untagged classes. Objects whose class is not tagged are not included.
3311 </constant>
3312 </constants>
3313
3314 <p/>
3315 The Heap Visit Control Flags are returned by the heap callbacks
3316 and can be used to abort the iteration. For the
3317 <functionlink id="jvmtiHeapReferenceCallback">Heap
3318 Reference Callback</functionlink>, it can also be used
3319 to prune the graph of traversed references
3320 (<code>JVMTI_VISIT_OBJECTS</code> is not set).
3321
3322 <constants id="jvmtiHeapVisitControl"
3323 label="Heap Visit Control Flags"
3324 kind="bits"
3325 since="1.1">
3326 <constant id="JVMTI_VISIT_OBJECTS" num="0x100">
3327 If we are visiting an object and if this callback
3328 was initiated by <functionlink id="FollowReferences"/>,
3329 traverse the references of this object.
3330 Otherwise ignored.
3331 </constant>
3332 <constant id="JVMTI_VISIT_ABORT" num="0x8000">
3333 Abort the iteration. Ignore all other bits.
3334 </constant>
3335 </constants>
3336
3337 <p/>
3338 The Heap Reference Enumeration is provided by the
3339 <functionlink id="jvmtiHeapReferenceCallback">Heap
3340 Reference Callback</functionlink> and
3341 <functionlink id="jvmtiPrimitiveFieldCallback">Primitive Field
3342 Callback</functionlink> to
3343 describe the kind of reference
3344 being reported.
3345
3346 <constants id="jvmtiHeapReferenceKind"
3347 label="Heap Reference Enumeration"
3348 kind="enum"
3349 since="1.1">
3350 <constant id="JVMTI_HEAP_REFERENCE_CLASS" num="1">
3351 Reference from an object to its class.
3352 </constant>
3353 <constant id="JVMTI_HEAP_REFERENCE_FIELD" num="2">
3354 Reference from an object to the value of one of its instance fields.
3355 </constant>
3356 <constant id="JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT" num="3">
3357 Reference from an array to one of its elements.
3358 </constant>
3359 <constant id="JVMTI_HEAP_REFERENCE_CLASS_LOADER" num="4">
3360 Reference from a class to its class loader.
3361 </constant>
3362 <constant id="JVMTI_HEAP_REFERENCE_SIGNERS" num="5">
3363 Reference from a class to its signers array.
3364 </constant>
3365 <constant id="JVMTI_HEAP_REFERENCE_PROTECTION_DOMAIN" num="6">
3366 Reference from a class to its protection domain.
3367 </constant>
3368 <constant id="JVMTI_HEAP_REFERENCE_INTERFACE" num="7">
3369 Reference from a class to one of its interfaces.
3370 Note: interfaces are defined via a constant pool reference,
3371 so the referenced interfaces may also be reported with a
3372 <code>JVMTI_HEAP_REFERENCE_CONSTANT_POOL</code> reference kind.
3373 </constant>
3374 <constant id="JVMTI_HEAP_REFERENCE_STATIC_FIELD" num="8">
3375 Reference from a class to the value of one of its static fields.
3376 </constant>
3377 <constant id="JVMTI_HEAP_REFERENCE_CONSTANT_POOL" num="9">
3378 Reference from a class to a resolved entry in the constant pool.
3379 </constant>
3380 <constant id="JVMTI_HEAP_REFERENCE_SUPERCLASS" num="10">
3381 Reference from a class to its superclass.
3382 A callback is not sent if the superclass is <code>java.lang.Object</code>.
3383 Note: loaded classes define superclasses via a constant pool
3384 reference, so the referenced superclass may also be reported with
3385 a <code>JVMTI_HEAP_REFERENCE_CONSTANT_POOL</code> reference kind.
3386 </constant>
3387 <constant id="JVMTI_HEAP_REFERENCE_JNI_GLOBAL" num="21">
3388 Heap root reference: JNI global reference.
3389 </constant>
3390 <constant id="JVMTI_HEAP_REFERENCE_SYSTEM_CLASS" num="22">
3391 Heap root reference: System class.
3392 </constant>
3393 <constant id="JVMTI_HEAP_REFERENCE_MONITOR" num="23">
3394 Heap root reference: monitor.
3395 </constant>
3396 <constant id="JVMTI_HEAP_REFERENCE_STACK_LOCAL" num="24">
3397 Heap root reference: local variable on the stack.
3398 </constant>
3399 <constant id="JVMTI_HEAP_REFERENCE_JNI_LOCAL" num="25">
3400 Heap root reference: JNI local reference.
3401 </constant>
3402 <constant id="JVMTI_HEAP_REFERENCE_THREAD" num="26">
3403 Heap root reference: Thread.
3404 </constant>
3405 <constant id="JVMTI_HEAP_REFERENCE_OTHER" num="27">
3406 Heap root reference: other heap root reference.
3407 </constant>
3408 </constants>
3409
3410 <p/>
3411 Definitions for the single character type descriptors of
3412 primitive types.
3413
3414 <constants id="jvmtiPrimitiveType"
3415 label="Primitive Type Enumeration"
3416 kind="enum"
3417 since="1.1">
3418 <constant id="JVMTI_PRIMITIVE_TYPE_BOOLEAN" num="90">
3419 'Z' - Java programming language <code>boolean</code> - JNI <code>jboolean</code>
3420 </constant>
3421 <constant id="JVMTI_PRIMITIVE_TYPE_BYTE" num="66">
3422 'B' - Java programming language <code>byte</code> - JNI <code>jbyte</code>
3423 </constant>
3424 <constant id="JVMTI_PRIMITIVE_TYPE_CHAR" num="67">
3425 'C' - Java programming language <code>char</code> - JNI <code>jchar</code>
3426 </constant>
3427 <constant id="JVMTI_PRIMITIVE_TYPE_SHORT" num="83">
3428 'S' - Java programming language <code>short</code> - JNI <code>jshort</code>
3429 </constant>
3430 <constant id="JVMTI_PRIMITIVE_TYPE_INT" num="73">
3431 'I' - Java programming language <code>int</code> - JNI <code>jint</code>
3432 </constant>
3433 <constant id="JVMTI_PRIMITIVE_TYPE_LONG" num="74">
3434 'J' - Java programming language <code>long</code> - JNI <code>jlong</code>
3435 </constant>
3436 <constant id="JVMTI_PRIMITIVE_TYPE_FLOAT" num="70">
3437 'F' - Java programming language <code>float</code> - JNI <code>jfloat</code>
3438 </constant>
3439 <constant id="JVMTI_PRIMITIVE_TYPE_DOUBLE" num="68">
3440 'D' - Java programming language <code>double</code> - JNI <code>jdouble</code>
3441 </constant>
3442 </constants>
3443 </intro>
3444
3445 <typedef id="jvmtiHeapReferenceInfoField"
3446 label="Reference information structure for Field references"
3447 since="1.1">
3448 <description>
3449 Reference information returned for
3450 <datalink id="JVMTI_HEAP_REFERENCE_FIELD"/> and
3451 <datalink id="JVMTI_HEAP_REFERENCE_STATIC_FIELD"/> references.
3452 </description>
3453 <field id="index">
3454 <jint/>
3455 <description>
3456 For <datalink id="JVMTI_HEAP_REFERENCE_FIELD"/>, the
3457 referrer object is not a class or an inteface.
3458 In this case, <code>index</code> is the index of the field
3459 in the class of the referrer object.
3460 This class is referred to below as <i>C</i>.
3461 <p/>
3462 For <datalink id="JVMTI_HEAP_REFERENCE_STATIC_FIELD"/>,
3463 the referrer object is a class (referred to below as <i>C</i>)
3464 or an interface (referred to below as <i>I</i>).
3465 In this case, <code>index</code> is the index of the field in
3466 that class or interface.
3467 <p/>
3468 If the referrer object is not an interface, then the field
3469 indices are determined as follows:
3470 <ul>
3471 <li>make a list of all the fields in <i>C</i> and its
3472 superclasses, starting with all the fields in
3473 <code>java.lang.Object</code> and ending with all the
3474 fields in <i>C</i>.</li>
3475 <li>Within this list, put
3476 the fields for a given class in the order returned by
3477 <functionlink id="GetClassFields"/>.</li>
3478 <li>Assign the fields in this list indices
3479 <i>n</i>, <i>n</i>+1, ..., in order, where <i>n</i>
3480 is the count of the fields in all the interfaces
3481 implemented by <i>C</i>.
3482 Note that <i>C</i> implements all interfaces
3483 directly implemented by its superclasses; as well
3484 as all superinterfaces of these interfaces.</li>
3485 </ul>
3486 If the referrer object is an interface, then the field
3487 indices are determined as follows:
3488 <ul>
3489 <li>make a list of the fields directly declared in
3490 <i>I</i>.</li>
3491 <li>Within this list, put
3492 the fields in the order returned by
3493 <functionlink id="GetClassFields"/>.</li>
3494 <li>Assign the fields in this list indices
3495 <i>n</i>, <i>n</i>+1, ..., in order, where <i>n</i>
3496 is the count of the fields in all the superinterfaces
3497 of <i>I</i>.</li>
3498 </ul>
3499 All fields are included in this computation, regardless of
3500 field modifier (static, public, private, etc).
3501 <p/>
3502 For example, given the following classes and interfaces:
3503 <example>
3504 interface I0 {
3505 int p = 0;
3506 }
3507
3508 interface I1 extends I0 {
3509 int x = 1;
3510 }
3511
3512 interface I2 extends I0 {
3513 int y = 2;
3514 }
3515
3516 class C1 implements I1 {
3517 public static int a = 3;
3518 private int b = 4;
3519 }
3520
3521 class C2 extends C1 implements I2 {
3522 static int q = 5;
3523 final int r = 6;
3524 }
3525 </example>
3526 Assume that <functionlink id="GetClassFields"/> called on
3527 <code>C1</code> returns the fields of <code>C1</code> in the
3528 order: a, b; and that the fields of <code>C2</code> are
3529 returned in the order: q, r.
3530 An instance of class <code>C1</code> will have the
3531 following field indices:
3532 <blockquote><table>
3533 <tr>
3534 <td class="centered">
3535 a
3536 </td>
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 <td class="centered">
3549 b
3550 </td>
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>
3565 <td class="centered">
3566 a
3567 </td>
3568 <td class="centered">
3569 3
3570 </td>
3571 <td>
3572 The count of the fields in the interfaces
3573 implemented by <code>C2</code> is three (<i>n</i>=3):
3574 <code>p</code> of <code>I0</code>,
3575 <code>x</code> of <code>I1</code> and <code>y</code> of <code>I2</code>
3576 (an interface of <code>C2</code>). Note that the field <code>p</code>
3577 of <code>I0</code> is only included once.
3578 </td>
3579 </tr>
3580 <tr>
3581 <td class="centered">
3582 b
3583 </td>
3584 <td class="centered">
3585 4
3586 </td>
3587 <td>
3588 the subsequent index to "a".
3589 </td>
3590 </tr>
3591 <tr>
3592 <td class="centered">
3593 q
3594 </td>
3595 <td class="centered">
3596 5
3597 </td>
3598 <td>
3599 the subsequent index to "b".
3600 </td>
3601 </tr>
3602 <tr>
3603 <td class="centered">
3604 r
3605 </td>
3606 <td class="centered">
3607 6
3608 </td>
3609 <td>
3610 the subsequent index to "q".
3611 </td>
3612 </tr>
3613 </table></blockquote>
3614 The class <code>C2</code> will have the same field indices.
3615 Note that a field may have a different index depending on the
3616 object that is viewing it -- for example field "a" above.
3617 Note also: not all field indices may be visible from the
3618 callbacks, but all indices are shown for illustrative purposes.
3619 <p/>
3620 The interface <code>I1</code> will have the
3621 following field indices:
3622 <blockquote><table>
3623 <tr>
3624 <td class="centered">
3625 x
3626 </td>
3627 <td class="centered">
3628 1
3629 </td>
3630 <td>
3631 The count of the fields in the superinterfaces
3632 of <code>I1</code> is one (<i>n</i>=1):
3633 <code>p</code> of <code>I0</code>.
3634 </td>
3635 </tr>
3636 </table></blockquote>
3637 </description>
3638 </field>
3639 </typedef>
3640
3641 <typedef id="jvmtiHeapReferenceInfoArray"
3642 label="Reference information structure for Array references"
3643 since="1.1">
3644 <description>
3645 Reference information returned for
3646 <datalink id="JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT"/> references.
3647 </description>
3648 <field id="index">
3649 <jint/>
3650 <description>
3651 The array index.
3652 </description>
3653 </field>
3654 </typedef>
3655
3656 <typedef id="jvmtiHeapReferenceInfoConstantPool"
3657 label="Reference information structure for Constant Pool references"
3658 since="1.1">
3659 <description>
3660 Reference information returned for
3661 <datalink id="JVMTI_HEAP_REFERENCE_CONSTANT_POOL"/> references.
3662 </description>
3663 <field id="index">
3664 <jint/>
3665 <description>
3666 The index into the constant pool of the class. See the description in
3667 <vmspec chapter="4.4"/>.
3668 </description>
3669 </field>
3670 </typedef>
3671
3672 <typedef id="jvmtiHeapReferenceInfoStackLocal"
3673 label="Reference information structure for Local Variable references"
3674 since="1.1">
3675 <description>
3676 Reference information returned for
3677 <datalink id="JVMTI_HEAP_REFERENCE_STACK_LOCAL"/> references.
3678 </description>
3679 <field id="thread_tag">
3680 <jlong/>
3681 <description>
3682 The tag of the thread corresponding to this stack, zero if not tagged.
3683 </description>
3684 </field>
3685 <field id="thread_id">
3686 <jlong/>
3687 <description>
3688 The unique thread ID of the thread corresponding to this stack.
3689 </description>
3690 </field>
3691 <field id="depth">
3692 <jint/>
3693 <description>
3694 The depth of the frame.
3695 </description>
3696 </field>
3697 <field id="method">
3698 <jmethodID/>
3699 <description>
3700 The method executing in this frame.
3701 </description>
3702 </field>
3703 <field id="location">
3704 <jlocation/>
3705 <description>
3706 The currently executing location in this frame.
3707 </description>
3708 </field>
3709 <field id="slot">
3710 <jint/>
3711 <description>
3712 The slot number of the local variable.
3713 </description>
3714 </field>
3715 </typedef>
3716
3717 <typedef id="jvmtiHeapReferenceInfoJniLocal"
3718 label="Reference information structure for JNI local references"
3719 since="1.1">
3720 <description>
3721 Reference information returned for
3722 <datalink id="JVMTI_HEAP_REFERENCE_JNI_LOCAL"/> references.
3723 </description>
3724 <field id="thread_tag">
3725 <jlong/>
3726 <description>
3727 The tag of the thread corresponding to this stack, zero if not tagged.
3728 </description>
3729 </field>
3730 <field id="thread_id">
3731 <jlong/>
3732 <description>
3733 The unique thread ID of the thread corresponding to this stack.
3734 </description>
3735 </field>
3736 <field id="depth">
3737 <jint/>
3738 <description>
3739 The depth of the frame.
3740 </description>
3741 </field>
3742 <field id="method">
3743 <jmethodID/>
3744 <description>
3745 The method executing in this frame.
3746 </description>
3747 </field>
3748 </typedef>
3749
3750 <typedef id="jvmtiHeapReferenceInfoReserved"
3751 label="Reference information structure for Other references"
3752 since="1.1">
3753 <description>
3754 Reference information returned for other references.
3755 </description>
3756 <field id="reserved1">
3757 <jlong/>
3758 <description>
3759 reserved for future use.
3760 </description>
3761 </field>
3762 <field id="reserved2">
3763 <jlong/>
3764 <description>
3765 reserved for future use.
3766 </description>
3767 </field>
3768 <field id="reserved3">
3769 <jlong/>
3770 <description>
3771 reserved for future use.
3772 </description>
3773 </field>
3774 <field id="reserved4">
3775 <jlong/>
3776 <description>
3777 reserved for future use.
3778 </description>
3779 </field>
3780 <field id="reserved5">
3781 <jlong/>
3782 <description>
3783 reserved for future use.
3784 </description>
3785 </field>
3786 <field id="reserved6">
3787 <jlong/>
3788 <description>
3789 reserved for future use.
3790 </description>
3791 </field>
3792 <field id="reserved7">
3793 <jlong/>
3794 <description>
3795 reserved for future use.
3796 </description>
3797 </field>
3798 <field id="reserved8">
3799 <jlong/>
3800 <description>
3801 reserved for future use.
3802 </description>
3803 </field>
3804 </typedef>
3805
3806 <uniontypedef id="jvmtiHeapReferenceInfo"
3807 label="Reference information structure"
3808 since="1.1">
3809 <description>
3810 The information returned about referrers.
3811 Represented as a union of the various kinds of reference information.
3812 </description>
3813 <field id="field">
3814 <struct>jvmtiHeapReferenceInfoField</struct>
3815 <description>
3816 The referrer information for
3817 <datalink id="JVMTI_HEAP_REFERENCE_FIELD"/>
3818 and <datalink id="JVMTI_HEAP_REFERENCE_STATIC_FIELD"/> references.
3819 </description>
3820 </field>
3821 <field id="array">
3822 <struct>jvmtiHeapReferenceInfoArray</struct>
3823 <description>
3824 The referrer information for
3825 For <datalink id="JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT"/> references.
3826 </description>
3827 </field>
3828 <field id="constant_pool">
3829 <struct>jvmtiHeapReferenceInfoConstantPool</struct>
3830 <description>
3831 The referrer information for
3832 For <datalink id="JVMTI_HEAP_REFERENCE_CONSTANT_POOL"/> references.
3833 </description>
3834 </field>
3835 <field id="stack_local">
3836 <struct>jvmtiHeapReferenceInfoStackLocal</struct>
3837 <description>
3838 The referrer information for
3839 For <datalink id="JVMTI_HEAP_REFERENCE_STACK_LOCAL"/> references.
3840 </description>
3841 </field>
3842 <field id="jni_local">
3843 <struct>jvmtiHeapReferenceInfoJniLocal</struct>
3844 <description>
3845 The referrer information for
3846 For <datalink id="JVMTI_HEAP_REFERENCE_JNI_LOCAL"/> references.
3847 </description>
3848 </field>
3849 <field id="other">
3850 <struct>jvmtiHeapReferenceInfoReserved</struct>
3851 <description>
3852 reserved for future use.
3853 </description>
3854 </field>
3855 </uniontypedef>
3856
3857 <typedef id="jvmtiHeapCallbacks"
3858 label="Heap callback function structure"
3859 since="1.1">
3860 <field id="heap_iteration_callback">
3861 <ptrtype>
3862 <struct>jvmtiHeapIterationCallback</struct>
3863 </ptrtype>
3864 <description>
3865 The callback to be called to describe an
3866 object in the heap. Used by the
3867 <functionlink id="IterateThroughHeap"/> function, ignored by the
3868 <functionlink id="FollowReferences"/> function.
3869 </description>
3870 </field>
3871 <field id="heap_reference_callback">
3872 <ptrtype>
3873 <struct>jvmtiHeapReferenceCallback</struct>
3874 </ptrtype>
3875 <description>
3876 The callback to be called to describe an
3877 object reference. Used by the
3878 <functionlink id="FollowReferences"/> function, ignored by the
3879 <functionlink id="IterateThroughHeap"/> function.
3880 </description>
3881 </field>
3882 <field id="primitive_field_callback">
3883 <ptrtype>
3884 <struct>jvmtiPrimitiveFieldCallback</struct>
3885 </ptrtype>
3886 <description>
3887 The callback to be called to describe a
3888 primitive field.
3889 </description>
3890 </field>
3891 <field id="array_primitive_value_callback">
3892 <ptrtype>
3893 <struct>jvmtiArrayPrimitiveValueCallback</struct>
3894 </ptrtype>
3895 <description>
3896 The callback to be called to describe an
3897 array of primitive values.
3898 </description>
3899 </field>
3900 <field id="string_primitive_value_callback">
3901 <ptrtype>
3902 <struct>jvmtiStringPrimitiveValueCallback</struct>
3903 </ptrtype>
3904 <description>
3905 The callback to be called to describe a String value.
3906 </description>
3907 </field>
3908 <field id="reserved5">
3909 <ptrtype>
3910 <struct>jvmtiReservedCallback</struct>
3911 </ptrtype>
3912 <description>
3913 Reserved for future use..
3914 </description>
3915 </field>
3916 <field id="reserved6">
3917 <ptrtype>
3918 <struct>jvmtiReservedCallback</struct>
3919 </ptrtype>
3920 <description>
3921 Reserved for future use..
3922 </description>
3923 </field>
3924 <field id="reserved7">
3925 <ptrtype>
3926 <struct>jvmtiReservedCallback</struct>
3927 </ptrtype>
3928 <description>
3929 Reserved for future use..
3930 </description>
3931 </field>
3932 <field id="reserved8">
3933 <ptrtype>
3934 <struct>jvmtiReservedCallback</struct>
3935 </ptrtype>
3936 <description>
3937 Reserved for future use..
3938 </description>
3939 </field>
3940 <field id="reserved9">
3941 <ptrtype>
3942 <struct>jvmtiReservedCallback</struct>
3943 </ptrtype>
3944 <description>
3945 Reserved for future use..
3946 </description>
3947 </field>
3948 <field id="reserved10">
3949 <ptrtype>
3950 <struct>jvmtiReservedCallback</struct>
3951 </ptrtype>
3952 <description>
3953 Reserved for future use..
3954 </description>
3955 </field>
3956 <field id="reserved11">
3957 <ptrtype>
3958 <struct>jvmtiReservedCallback</struct>
3959 </ptrtype>
3960 <description>
3961 Reserved for future use..
3962 </description>
3963 </field>
3964 <field id="reserved12">
3965 <ptrtype>
3966 <struct>jvmtiReservedCallback</struct>
3967 </ptrtype>
3968 <description>
3969 Reserved for future use..
3970 </description>
3971 </field>
3972 <field id="reserved13">
3973 <ptrtype>
3974 <struct>jvmtiReservedCallback</struct>
3975 </ptrtype>
3976 <description>
3977 Reserved for future use..
3978 </description>
3979 </field>
3980 <field id="reserved14">
3981 <ptrtype>
3982 <struct>jvmtiReservedCallback</struct>
3983 </ptrtype>
3984 <description>
3985 Reserved for future use..
3986 </description>
3987 </field>
3988 <field id="reserved15">
3989 <ptrtype>
3990 <struct>jvmtiReservedCallback</struct>
3991 </ptrtype>
3992 <description>
3993 Reserved for future use..
3994 </description>
3995 </field>
3996 </typedef>
3997
3998
3999 <intro>
4000 <rationale>
4001 The heap dumping functionality (below) uses a callback
4002 for each object. While it would seem that a buffered approach
4003 would provide better throughput, tests do
4004 not show this to be the case--possibly due to locality of
4005 memory reference or array access overhead.
4006 </rationale>
4007
4008 <issue>
4009 Still under investigation as to if java.lang.ref references
4010 are reported as a different type of reference.
4011 </issue>
4012
4013 <issue>
4014 Should or can an indication of the cost or relative cost of
4015 these operations be included?
4016 </issue>
4017
4018 </intro>
4019
4020 <callback id="jvmtiHeapIterationCallback" since="1.1">
4021 <jint/>
4022 <synopsis>Heap Iteration Callback</synopsis>
4023 <description>
4024 Agent supplied callback function.
4025 Describes (but does not pass in) an object in the heap.
4026 <p/>
4027 This function should return a bit vector of the desired
4028 <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>.
4029 This will determine if the entire iteration should be aborted
4030 (the <code>JVMTI_VISIT_OBJECTS</code> flag is ignored).
4031 <p/>
4032 See the <internallink id="heapCallbacks">heap callback
4033 function restrictions</internallink>.
4034 </description>
4035 <parameters>
4036 <param id="class_tag">
4037 <jlong/>
4038 <description>
4039 The tag of the class of object (zero if the class is not tagged).
4040 If the object represents a runtime class,
4041 the <code>class_tag</code> is the tag
4042 associated with <code>java.lang.Class</code>
4043 (zero if <code>java.lang.Class</code> is not tagged).
4044 </description>
4045 </param>
4046 <param id="size">
4047 <jlong/>
4048 <description>
4049 Size of the object (in bytes). See <functionlink id="GetObjectSize"/>.
4050 </description>
4051 </param>
4052 <param id="tag_ptr">
4053 <outptr><jlong/></outptr>
4054 <description>
4055 The object tag value, or zero if the object is not tagged.
4056 To set the tag value to be associated with the object
4057 the agent sets the <code>jlong</code> pointed to by the parameter.
4058 </description>
4059 </param>
4060 <param id="length">
4061 <jint/>
4062 <description>
4063 If this object is an array, the length of the array. Otherwise negative one (-1).
4064 </description>
4065 </param>
4066 <param id="user_data">
4067 <outptr><void/></outptr>
4068 <description>
4069 The user supplied data that was passed into the iteration function.
4070 </description>
4071 </param>
4072 </parameters>
4073 </callback>
4074
4075 <callback id="jvmtiHeapReferenceCallback" since="1.1">
4076 <jint/>
4077 <synopsis>Heap Reference Callback</synopsis>
4078 <description>
4079 Agent supplied callback function.
4080 Describes a reference from an object or the VM (the referrer) to another object
4081 (the referree) or a heap root to a referree.
4082 <p/>
4083 This function should return a bit vector of the desired
4084 <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>.
4085 This will determine if the objects referenced by the referree
4086 should be visited or if the entire iteration should be aborted.
4087 <p/>
4088 See the <internallink id="heapCallbacks">heap callback
4089 function restrictions</internallink>.
4090 </description>
4091 <parameters>
4092 <param id="reference_kind">
4093 <enum>jvmtiHeapReferenceKind</enum>
4094 <description>
4095 The kind of reference.
4096 </description>
4097 </param>
4098 <param id="reference_info">
4099 <inptr>
4100 <struct>jvmtiHeapReferenceInfo</struct>
4101 </inptr>
4102 <description>
4103 Details about the reference.
4104 Set when the <datalink id="jvmtiHeapReferenceCallback.reference_kind">reference_kind</datalink> is
4105 <datalink id="JVMTI_HEAP_REFERENCE_FIELD"/>,
4106 <datalink id="JVMTI_HEAP_REFERENCE_STATIC_FIELD"/>,
4107 <datalink id="JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT"/>,
4108 <datalink id="JVMTI_HEAP_REFERENCE_CONSTANT_POOL"/>,
4109 <datalink id="JVMTI_HEAP_REFERENCE_STACK_LOCAL"/>,
4110 or <datalink id="JVMTI_HEAP_REFERENCE_JNI_LOCAL"/>.
4111 Otherwise <code>NULL</code>.
4112 </description>
4113 </param>
4114 <param id="class_tag">
4115 <jlong/>
4116 <description>
4117 The tag of the class of referree object (zero if the class is not tagged).
4118 If the referree object represents a runtime class,
4119 the <code>class_tag</code> is the tag
4120 associated with <code>java.lang.Class</code>
4121 (zero if <code>java.lang.Class</code> is not tagged).
4122 </description>
4123 </param>
4124 <param id="referrer_class_tag">
4125 <jlong/>
4126 <description>
4127 The tag of the class of the referrer object (zero if the class is not tagged
4128 or the referree is a heap root). If the referrer object represents a runtime
4129 class, the <code>referrer_class_tag</code> is the tag associated with
4130 the <code>java.lang.Class</code>
4131 (zero if <code>java.lang.Class</code> is not tagged).
4132 </description>
4133 </param>
4134 <param id="size">
4135 <jlong/>
4136 <description>
4137 Size of the referree object (in bytes).
4138 See <functionlink id="GetObjectSize"/>.
4139 </description>
4140 </param>
4141 <param id="tag_ptr">
4142 <outptr><jlong/></outptr>
4143 <description>
4144 Points to the referree object tag value, or zero if the object is not
4145 tagged.
4146 To set the tag value to be associated with the object
4147 the agent sets the <code>jlong</code> pointed to by the parameter.
4148 </description>
4149 </param>
4150 <param id="referrer_tag_ptr">
4151 <outptr><jlong/></outptr>
4152 <description>
4153 Points to the tag of the referrer object, or
4154 points to the zero if the referrer
4155 object is not tagged.
4156 <code>NULL</code> if the referrer in not an object (that is,
4157 this callback is reporting a heap root).
4158 To set the tag value to be associated with the referrer object
4159 the agent sets the <code>jlong</code> pointed to by the parameter.
4160 If this callback is reporting a reference from an object to itself,
4161 <code>referrer_tag_ptr == tag_ptr</code>.
4162 </description>
4163 </param>
4164 <param id="length">
4165 <jint/>
4166 <description>
4167 If this object is an array, the length of the array. Otherwise negative one (-1).
4168 </description>
4169 </param>
4170 <param id="user_data">
4171 <outptr><void/></outptr>
4172 <description>
4173 The user supplied data that was passed into the iteration function.
4174 </description>
4175 </param>
4176 </parameters>
4177 </callback>
4178
4179 <callback id="jvmtiPrimitiveFieldCallback" since="1.1">
4180 <jint/>
4181 <synopsis>Primitive Field Callback</synopsis>
4182 <description>
4183 Agent supplied callback function which
4184 describes a primitive field of an object (<i>the object</i>).
4185 A primitive field is a field whose type is a primitive type.
4186 This callback will describe a static field if the object is a class,
4187 and otherwise will describe an instance field.
4188 <p/>
4189 This function should return a bit vector of the desired
4190 <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>.
4191 This will determine if the entire iteration should be aborted
4192 (the <code>JVMTI_VISIT_OBJECTS</code> flag is ignored).
4193 <p/>
4194 See the <internallink id="heapCallbacks">heap callback
4195 function restrictions</internallink>.
4196 </description>
4197 <parameters>
4198 <param id="kind">
4199 <enum>jvmtiHeapReferenceKind</enum>
4200 <description>
4201 The kind of field -- instance or static (<datalink id="JVMTI_HEAP_REFERENCE_FIELD"/> or
4202 <datalink id="JVMTI_HEAP_REFERENCE_STATIC_FIELD"/>).
4203 </description>
4204 </param>
4205 <param id="info">
4206 <inptr>
4207 <struct>jvmtiHeapReferenceInfo</struct>
4208 </inptr>
4209 <description>
4210 Which field (the field index).
4211 </description>
4212 </param>
4213 <param id="object_class_tag">
4214 <jlong/>
4215 <description>
4216 The tag of the class of the object (zero if the class is not tagged).
4217 If the object represents a runtime class, the
4218 <code>object_class_tag</code> is the tag
4219 associated with <code>java.lang.Class</code>
4220 (zero if <code>java.lang.Class</code> is not tagged).
4221 </description>
4222 </param>
4223 <param id="object_tag_ptr">
4224 <outptr><jlong/></outptr>
4225 <description>
4226 Points to the tag of the object, or zero if the object is not
4227 tagged.
4228 To set the tag value to be associated with the object
4229 the agent sets the <code>jlong</code> pointed to by the parameter.
4230 </description>
4231 </param>
4232 <param id="value">
4233 <jvalue/>
4234 <description>
4235 The value of the field.
4236 </description>
4237 </param>
4238 <param id="value_type">
4239 <enum>jvmtiPrimitiveType</enum>
4240 <description>
4241 The type of the field.
4242 </description>
4243 </param>
4244 <param id="user_data">
4245 <outptr><void/></outptr>
4246 <description>
4247 The user supplied data that was passed into the iteration function.
4248 </description>
4249 </param>
4250 </parameters>
4251 </callback>
4252
4253 <callback id="jvmtiArrayPrimitiveValueCallback" since="1.1">
4254 <jint/>
4255 <synopsis>Array Primitive Value Callback</synopsis>
4256 <description>
4257 Agent supplied callback function.
4258 Describes the values in an array of a primitive type.
4259 <p/>
4260 This function should return a bit vector of the desired
4261 <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>.
4262 This will determine if the entire iteration should be aborted
4263 (the <code>JVMTI_VISIT_OBJECTS</code> flag is ignored).
4264 <p/>
4265 See the <internallink id="heapCallbacks">heap callback
4266 function restrictions</internallink>.
4267 </description>
4268 <parameters>
4269 <param id="class_tag">
4270 <jlong/>
4271 <description>
4272 The tag of the class of the array object (zero if the class is not tagged).
4273 </description>
4274 </param>
4275 <param id="size">
4276 <jlong/>
4277 <description>
4278 Size of the array (in bytes).
4279 See <functionlink id="GetObjectSize"/>.
4280 </description>
4281 </param>
4282 <param id="tag_ptr">
4283 <outptr><jlong/></outptr>
4284 <description>
4285 Points to the tag of the array object, or zero if the object is not
4286 tagged.
4287 To set the tag value to be associated with the object
4288 the agent sets the <code>jlong</code> pointed to by the parameter.
4289 </description>
4290 </param>
4291 <param id="element_count">
4292 <jint/>
4293 <description>
4294 The length of the primitive array.
4295 </description>
4296 </param>
4297 <param id="element_type">
4298 <enum>jvmtiPrimitiveType</enum>
4299 <description>
4300 The type of the elements of the array.
4301 </description>
4302 </param>
4303 <param id="elements">
4304 <vmbuf><void/></vmbuf>
4305 <description>
4306 The elements of the array in a packed array of <code>element_count</code>
4307 items of <code>element_type</code> size each.
4308 </description>
4309 </param>
4310 <param id="user_data">
4311 <outptr><void/></outptr>
4312 <description>
4313 The user supplied data that was passed into the iteration function.
4314 </description>
4315 </param>
4316 </parameters>
4317 </callback>
4318
4319 <callback id="jvmtiStringPrimitiveValueCallback" since="1.1">
4320 <jint/>
4321 <synopsis>String Primitive Value Callback</synopsis>
4322 <description>
4323 Agent supplied callback function.
4324 Describes the value of a java.lang.String.
4325 <p/>
4326 This function should return a bit vector of the desired
4327 <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>.
4328 This will determine if the entire iteration should be aborted
4329 (the <code>JVMTI_VISIT_OBJECTS</code> flag is ignored).
4330 <p/>
4331 See the <internallink id="heapCallbacks">heap callback
4332 function restrictions</internallink>.
4333 </description>
4334 <parameters>
4335 <param id="class_tag">
4336 <jlong/>
4337 <description>
4338 The tag of the class of the String class (zero if the class is not tagged).
4339 <issue>Is this needed?</issue>
4340 </description>
4341 </param>
4342 <param id="size">
4343 <jlong/>
4344 <description>
4345 Size of the string (in bytes).
4346 See <functionlink id="GetObjectSize"/>.
4347 </description>
4348 </param>
4349 <param id="tag_ptr">
4350 <outptr><jlong/></outptr>
4351 <description>
4352 Points to the tag of the String object, or zero if the object is not
4353 tagged.
4354 To set the tag value to be associated with the object
4355 the agent sets the <code>jlong</code> pointed to by the parameter.
4356 </description>
4357 </param>
4358 <param id="value">
4359 <vmbuf><jchar/></vmbuf>
4360 <description>
4361 The value of the String, encoded as a Unicode string.
4362 </description>
4363 </param>
4364 <param id="value_length">
4365 <jint/>
4366 <description>
4367 The length of the string.
4368 The length is equal to the number of 16-bit Unicode
4369 characters in the string.
4370 </description>
4371 </param>
4372 <param id="user_data">
4373 <outptr><void/></outptr>
4374 <description>
4375 The user supplied data that was passed into the iteration function.
4376 </description>
4377 </param>
4378 </parameters>
4379 </callback>
4380
4381
4382 <callback id="jvmtiReservedCallback" since="1.1">
4383 <jint/>
4384 <synopsis>reserved for future use Callback</synopsis>
4385 <description>
4386 Placeholder -- reserved for future use.
4387 </description>
4388 <parameters>
4389 </parameters>
4390 </callback>
4391
4392 <function id="FollowReferences" num="115" since="1.1">
4393 <synopsis>Follow References</synopsis>
4394 <description>
4395 This function initiates a traversal over the objects that are
4396 directly and indirectly reachable from the specified object or,
4397 if <code>initial_object</code> is not specified, all objects
4398 reachable from the heap roots.
4399 The heap root are the set of system classes,
4400 JNI globals, references from thread stacks, and other objects used as roots
4401 for the purposes of garbage collection.
4402 <p/>
4403 This function operates by traversing the reference graph.
4404 Let <i>A</i>, <i>B</i>, ... represent objects.
4405 When a reference from <i>A</i> to <i>B</i> is traversed,
4406 when a reference from a heap root to <i>B</i> is traversed,
4407 or when <i>B</i> is specified as the <paramlink id="initial_object"/>,
4408 then <i>B</i> is said to be <i>visited</i>.
4409 A reference from <i>A</i> to <i>B</i> is not traversed until <i>A</i>
4410 is visited.
4411 References are reported in the same order that the references are traversed.
4412 Object references are reported by invoking the agent supplied
4413 callback function <functionlink id="jvmtiHeapReferenceCallback"/>.
4414 In a reference from <i>A</i> to <i>B</i>, <i>A</i> is known
4415 as the <i>referrer</i> and <i>B</i> as the <i>referree</i>.
4416 The callback is invoked exactly once for each reference from a referrer;
4417 this is true even if there are reference cycles or multiple paths to
4418 the referrer.
4419 There may be more than one reference between a referrer and a referree,
4420 each reference is reported.
4421 These references may be distinguished by examining the
4422 <datalink
4423 id="jvmtiHeapReferenceCallback.reference_kind"><code>reference_kind</code></datalink>
4424 and
4425 <datalink
4426 id="jvmtiHeapReferenceCallback.reference_info"><code>reference_info</code></datalink>
4427 parameters of the <functionlink id="jvmtiHeapReferenceCallback"/> callback.
4428 <p/>
4429 This function reports a Java programming language view of object references,
4430 not a virtual machine implementation view. The following object references
4431 are reported when they are non-null:
4432 <ul>
4433 <li>Instance objects report references to each non-primitive instance fields
4434 (including inherited fields).</li>
4435 <li>Instance objects report a reference to the object type (class).</li>
4436 <li>Classes report a reference to the superclass and directly
4437 implemented/extended interfaces.</li>
4438 <li>Classes report a reference to the class loader, protection domain,
4439 signers, and resolved entries in the constant pool.</li>
4440 <li>Classes report a reference to each directly declared non-primitive
4441 static field.</li>
4442 <li>Arrays report a reference to the array type (class) and each
4443 array element.</li>
4444 <li>Primitive arrays report a reference to the array type.</li>
4445 </ul>
4446 <p/>
4447 This function can also be used to examine primitive (non-object) values.
4448 The primitive value of an array or String
4449 is reported after the object has been visited;
4450 it is reported by invoking the agent supplied callback function
4451 <functionlink id="jvmtiArrayPrimitiveValueCallback"/> or
4452 <functionlink id="jvmtiStringPrimitiveValueCallback"/>.
4453 A primitive field
4454 is reported after the object with that field is visited;
4455 it is reported by invoking the agent supplied callback function
4456 <functionlink id="jvmtiPrimitiveFieldCallback"/>.
4457 <p/>
4458 Whether a callback is provided or is <code>NULL</code> only determines
4459 whether the callback will be invoked, it does not influence
4460 which objects are visited nor does it influence whether other callbacks
4461 will be invoked.
4462 However, the
4463 <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>
4464 returned by <functionlink id="jvmtiHeapReferenceCallback"/>
4465 do determine if the objects referenced by the
4466 current object as visited.
4467 The <datalink id="jvmtiHeapFilter">heap filter flags</datalink>
4468 and <paramlink id="klass"/> provided as parameters to this function
4469 do not control which objects are visited but they do control which
4470 objects and primitive values are reported by the callbacks.
4471 For example, if the only callback that was set is
4472 <fieldlink id="array_primitive_value_callback" struct="jvmtiHeapCallbacks"/> and <code>klass</code>
4473 is set to the array of bytes class, then only arrays of byte will be
4474 reported.
4475 The table below summarizes this:
4476 <p/>
4477 <table>
4478 <tr>
4479 <th/>
4480 <th>
4481 Controls objects visited
4482 </th>
4483 <th>
4484 Controls objects reported
4485 </th>
4486 <th>
4487 Controls primitives reported
4488 </th>
4489 </tr>
4490 <tr>
4491 <th class="leftAligned">
4492 the
4493 <datalink id="jvmtiHeapVisitControl">Heap Visit Control Flags</datalink>
4494 returned by <functionlink id="jvmtiHeapReferenceCallback"/>
4495 </th>
4496 <td class="centered">
4497 <b>Yes</b>
4498 </td>
4499 <td class="centered">
4500 <b>Yes</b>, since visits are controlled
4501 </td>
4502 <td class="centered">
4503 <b>Yes</b>, since visits are controlled
4504 </td>
4505 </tr>
4506 <tr>
4507 <th class="leftAligned">
4508 <fieldlink id="array_primitive_value_callback" struct="jvmtiHeapCallbacks"/>
4509 in <paramlink id="callbacks"/> set
4510 </th>
4511 <td class="centered">
4512 No
4513 </td>
4514 <td class="centered">
4515 <b>Yes</b>
4516 </td>
4517 <td class="centered">
4518 No
4519 </td>
4520 </tr>
4521 <tr>
4522 <th class="leftAligned">
4523 <paramlink id="heap_filter"/>
4524 </th>
4525 <td class="centered">
4526 No
4527 </td>
4528 <td class="centered">
4529 <b>Yes</b>
4530 </td>
4531 <td class="centered">
4532 <b>Yes</b>
4533 </td>
4534 </tr>
4535 <tr>
4536 <th class="leftAligned">
4537 <paramlink id="klass"/>
4538 </th>
4539 <td class="centered">
4540 No
4541 </td>
4542 <td class="centered">
4543 <b>Yes</b>
4544 </td>
4545 <td class="centered">
4546 <b>Yes</b>
4547 </td>
4548 </tr>
4549 </table>
4550 <p/>
4551 During the execution of this function the state of the heap
4552 does not change: no objects are allocated, no objects are
4553 garbage collected, and the state of objects (including
4554 held values) does not change.
4555 As a result, threads executing Java
4556 programming language code, threads attempting to resume the
4557 execution of Java programming language code, and threads
4558 attempting to execute JNI functions are typically stalled.
4559 </description>
4560 <origin>new</origin>
4561 <capabilities>
4562 <required id="can_tag_objects"></required>
4563 </capabilities>
4564 <parameters>
4565 <param id="heap_filter">
4566 <jint/>
4567 <description>
4568 This bit vector of
4569 <datalink id="jvmtiHeapFilter">heap filter flags</datalink>.
4570 restricts the objects for which the callback function is called.
4571 This applies to both the object and primitive callbacks.
4572 </description>
4573 </param>
4574 <param id="klass">
4575 <ptrtype>
4576 <jclass/>
4577 <nullok>callbacks are not limited to instances of a particular
4578 class</nullok>
4579 </ptrtype>
4580 <description>
4581 Callbacks are only reported when the object is an instance of
4582 this class.
4583 Objects which are instances of a subclass of <code>klass</code>
4584 are not reported.
4585 If <code>klass</code> is an interface, no objects are reported.
4586 This applies to both the object and primitive callbacks.
4587 </description>
4588 </param>
4589 <param id="initial_object">
4590 <ptrtype>
4591 <jobject/>
4592 <nullok>references are followed from the heap roots</nullok>
4593 </ptrtype>
4594 <description>
4595 The object to follow
4596 </description>
4597 </param>
4598 <param id="callbacks">
4599 <inptr>
4600 <struct>jvmtiHeapCallbacks</struct>
4601 </inptr>
4602 <description>
4603 Structure defining the set of callback functions.
4604 </description>
4605 </param>
4606 <param id="user_data">
4607 <inbuf>
4608 <void/>
4609 <nullok><code>NULL</code> is passed as the user supplied data</nullok>
4610 </inbuf>
4611 <description>
4612 User supplied data to be passed to the callback.
4613 </description>
4614 </param>
4615 </parameters>
4616 <errors>
4617 <error id="JVMTI_ERROR_INVALID_CLASS">
4618 <paramlink id="klass"/> is not a valid class.
4619 </error>
4620 <error id="JVMTI_ERROR_INVALID_OBJECT">
4621 <paramlink id="initial_object"/> is not a valid object.
4622 </error>
4623 </errors>
4624 </function>
4625
4626
4627 <function id="IterateThroughHeap" num="116" since="1.1">
4628 <synopsis>Iterate Through Heap</synopsis>
4629 <description>
4630 Initiate an iteration over all objects in the heap.
4631 This includes both reachable and
4632 unreachable objects. Objects are visited in no particular order.
4633 <p/>
4634 Heap objects are reported by invoking the agent supplied
4635 callback function <functionlink id="jvmtiHeapIterationCallback"/>.
4636 References between objects are not reported.
4637 If only reachable objects are desired, or if object reference information
4638 is needed, use <functionlink id="FollowReferences"/>.
4639 <p/>
4640 This function can also be used to examine primitive (non-object) values.
4641 The primitive value of an array or String
4642 is reported after the object has been visited;
4643 it is reported by invoking the agent supplied callback function
4644 <functionlink id="jvmtiArrayPrimitiveValueCallback"/> or
4645 <functionlink id="jvmtiStringPrimitiveValueCallback"/>.
4646 A primitive field
4647 is reported after the object with that field is visited;
4648 it is reported by invoking the agent supplied
4649 callback function
4650 <functionlink id="jvmtiPrimitiveFieldCallback"/>.
4651 <p/>
4652 Unless the iteration is aborted by the
4653 <datalink id="jvmtiHeapVisitControl">Heap Visit Control Flags</datalink>
4654 returned by a callback, all objects in the heap are visited.
4655 Whether a callback is provided or is <code>NULL</code> only determines
4656 whether the callback will be invoked, it does not influence
4657 which objects are visited nor does it influence whether other callbacks
4658 will be invoked.
4659 The <datalink id="jvmtiHeapFilter">heap filter flags</datalink>
4660 and <paramlink id="klass"/> provided as parameters to this function
4661 do not control which objects are visited but they do control which
4662 objects and primitive values are reported by the callbacks.
4663 For example, if the only callback that was set is
4664 <fieldlink id="array_primitive_value_callback" struct="jvmtiHeapCallbacks"/> and <code>klass</code>
4665 is set to the array of bytes class, then only arrays of byte will be
4666 reported. The table below summarizes this (contrast this with
4667 <functionlink id="FollowReferences"/>):
4668 <p/>
4669 <table>
4670 <tr>
4671 <th/>
4672 <th>
4673 Controls objects visited
4674 </th>
4675 <th>
4676 Controls objects reported
4677 </th>
4678 <th>
4679 Controls primitives reported
4680 </th>
4681 </tr>
4682 <tr>
4683 <th class="leftAligned">
4684 the
4685 <datalink id="jvmtiHeapVisitControl">Heap Visit Control Flags</datalink>
4686 returned by <functionlink id="jvmtiHeapIterationCallback"/>
4687 </th>
4688 <td class="centered">
4689 No<br/>(unless they abort the iteration)
4690 </td>
4691 <td class="centered">
4692 No<br/>(unless they abort the iteration)
4693 </td>
4694 <td class="centered">
4695 No<br/>(unless they abort the iteration)
4696 </td>
4697 </tr>
4698 <tr>
4699 <th class="leftAligned">
4700 <fieldlink id="array_primitive_value_callback" struct="jvmtiHeapCallbacks"/>
4701 in <paramlink id="callbacks"/> set
4702 </th>
4703 <td class="centered">
4704 No
4705 </td>
4706 <td class="centered">
4707 <b>Yes</b>
4708 </td>
4709 <td class="centered">
4710 No
4711 </td>
4712 </tr>
4713 <tr>
4714 <th class="leftAligned">
4715 <paramlink id="heap_filter"/>
4716 </th>
4717 <td class="centered">
4718 No
4719 </td>
4720 <td class="centered">
4721 <b>Yes</b>
4722 </td>
4723 <td class="centered">
4724 <b>Yes</b>
4725 </td>
4726 </tr>
4727 <tr>
4728 <th class="leftAligned">
4729 <paramlink id="klass"/>
4730 </th>
4731 <td class="centered">
4732 No
4733 </td>
4734 <td class="centered">
4735 <b>Yes</b>
4736 </td>
4737 <td class="centered">
4738 <b>Yes</b>
4739 </td>
4740 </tr>
4741 </table>
4742 <p/>
4743 During the execution of this function the state of the heap
4744 does not change: no objects are allocated, no objects are
4745 garbage collected, and the state of objects (including
4746 held values) does not change.
4747 As a result, threads executing Java
4748 programming language code, threads attempting to resume the
4749 execution of Java programming language code, and threads
4750 attempting to execute JNI functions are typically stalled.
4751 </description>
4752 <origin>new</origin>
4753 <capabilities>
4754 <required id="can_tag_objects"></required>
4755 </capabilities>
4756 <parameters>
4757 <param id="heap_filter">
4758 <jint/>
4759 <description>
4760 This bit vector of
4761 <datalink id="jvmtiHeapFilter">heap filter flags</datalink>.
4762 restricts the objects for which the callback function is called.
4763 This applies to both the object and primitive callbacks.
4764 </description>
4765 </param>
4766 <param id="klass">
4767 <ptrtype>
4768 <jclass/>
4769 <nullok>callbacks are not limited to instances of a particular class</nullok>
4770 </ptrtype>
4771 <description>
4772 Callbacks are only reported when the object is an instance of
4773 this class.
4774 Objects which are instances of a subclass of <code>klass</code>
4775 are not reported.
4776 If <code>klass</code> is an interface, no objects are reported.
4777 This applies to both the object and primitive callbacks.
4778 </description>
4779 </param>
4780 <param id="callbacks">
4781 <inptr>
4782 <struct>jvmtiHeapCallbacks</struct>
4783 </inptr>
4784 <description>
4785 Structure defining the set callback functions.
4786 </description>
4787 </param>
4788 <param id="user_data">
4789 <inbuf>
4790 <void/>
4791 <nullok><code>NULL</code> is passed as the user supplied data</nullok>
4792 </inbuf>
4793 <description>
4794 User supplied data to be passed to the callback.
4795 </description>
4796 </param>
4797 </parameters>
4798 <errors>
4799 <error id="JVMTI_ERROR_INVALID_CLASS">
4800 <paramlink id="klass"/> is not a valid class.
4801 </error>
4802 </errors>
4803 </function>
4804
4805 <function id="GetTag" phase="start" num="106">
4806 <synopsis>Get Tag</synopsis>
4807 <description>
4808 Retrieve the tag associated with an object.
4809 The tag is a long value typically used to store a
4810 unique identifier or pointer to object information.
4811 The tag is set with
4812 <functionlink id="SetTag"></functionlink>.
4813 Objects for which no tags have been set return a
4814 tag value of zero.
4815 </description>
4816 <origin>new</origin>
4817 <capabilities>
4818 <required id="can_tag_objects"></required>
4819 </capabilities>
4820 <parameters>
4821 <param id="object">
4822 <jobject/>
4823 <description>
4824 The object whose tag is to be retrieved.
4825 </description>
4826 </param>
4827 <param id="tag_ptr">
4828 <outptr><jlong/></outptr>
4829 <description>
4830 On return, the referenced long is set to the value
4831 of the tag.
4832 </description>
4833 </param>
4834 </parameters>
4835 <errors>
4836 </errors>
4837 </function>
4838
4839 <function id="SetTag" phase="start" num="107">
4840 <synopsis>Set Tag</synopsis>
4841 <description>
4842 Set the tag associated with an object.
4843 The tag is a long value typically used to store a
4844 unique identifier or pointer to object information.
4845 The tag is visible with
4846 <functionlink id="GetTag"></functionlink>.
4847 </description>
4848 <origin>new</origin>
4849 <capabilities>
4850 <required id="can_tag_objects"></required>
4851 </capabilities>
4852 <parameters>
4853 <param id="object">
4854 <jobject/>
4855 <description>
4856 The object whose tag is to be set.
4857 </description>
4858 </param>
4859 <param id="tag">
4860 <jlong/>
4861 <description>
4862 The new value of the tag.
4863 </description>
4864 </param>
4865 </parameters>
4866 <errors>
4867 </errors>
4868 </function>
4869
4870 <function id="GetObjectsWithTags" num="114">
4871 <synopsis>Get Objects With Tags</synopsis>
4872 <description>
4873 Return objects in the heap with the specified tags.
4874 The format is parallel arrays of objects and tags.
4875 </description>
4876 <origin>new</origin>
4877 <capabilities>
4878 <required id="can_tag_objects"></required>
4879 </capabilities>
4880 <parameters>
4881 <param id="tag_count">
4882 <jint min="0"/>
4883 <description>
4884 Number of tags to scan for.
4885 </description>
4886 </param>
4887 <param id="tags">
4888 <inbuf incount="tag_count">
4889 <jlong/>
4890 </inbuf>
4891 <description>
4892 Scan for objects with these tags.
4893 Zero is not permitted in this array.
4894 </description>
4895 </param>
4896 <param id="count_ptr">
4897 <outptr>
4898 <jint/>
4899 </outptr>
4900 <description>
4901 Return the number of objects with any of the tags
4902 in <paramlink id="tags"/>.
4903 </description>
4904 </param>
4905 <param id="object_result_ptr">
4906 <allocbuf outcount="count_ptr">
4907 <jobject/>
4908 <nullok>this information is not returned</nullok>
4909 </allocbuf>
4910 <description>
4911 Returns the array of objects with any of the tags
4912 in <paramlink id="tags"/>.
4913 </description>
4914 </param>
4915 <param id="tag_result_ptr">
4916 <allocbuf outcount="count_ptr">
4917 <jlong/>
4918 <nullok>this information is not returned</nullok>
4919 </allocbuf>
4920 <description>
4921 For each object in <paramlink id="object_result_ptr"/>,
4922 return the tag at the corresponding index.
4923 </description>
4924 </param>
4925 </parameters>
4926 <errors>
4927 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
4928 Zero is present in <paramlink id="tags"></paramlink>.
4929 </error>
4930 </errors>
4931 </function>
4932
4933 <function id="ForceGarbageCollection" num="108">
4934 <synopsis>Force Garbage Collection</synopsis>
4935 <description>
4936 Force the VM to perform a garbage collection.
4937 The garbage collection is as complete as possible.
4938 This function does not cause finalizers to be run.
4939 This function does not return until the garbage collection
4940 is finished.
4941 <p/>
4942 Although garbage collection is as complete
4943 as possible there is no guarantee that all
4944 <eventlink id="ObjectFree"/>
4945 events will have been
4946 sent by the time that this function
4947 returns. In particular, an object may be
4948 prevented from being freed because it
4949 is awaiting finalization.
4950 </description>
4951 <origin>new</origin>
4952 <capabilities>
4953 </capabilities>
4954 <parameters>
4955 </parameters>
4956 <errors>
4957 </errors>
4958 </function>
4959
4960
4961 </category>
4962
4963 <category id="Heap_1_0" label="Heap (1.0)">
4964 <intro>
4965 <b>
4966 These functions and data types were introduced in the original
4967 <jvmti/> version 1.0 and have been superseded by more
4968 </b>
4969 <internallink id="Heap"><b>powerful and flexible versions</b></internallink>
4970 <b>
4971 which:
4972 </b>
4973 <ul>
4974 <li>
4975 <b>
4976 Allow access to primitive values (the value of Strings, arrays,
4977 and primitive fields)
4978 </b>
4979 </li>
4980 <li>
4981 <b>
4982 Allow the tag of the referrer to be set, thus enabling more
4983 efficient localized reference graph building
4984 </b>
4985 </li>
4986 <li>
4987 <b>
4988 Provide more extensive filtering abilities
4989 </b>
4990 </li>
4991 <li>
4992 <b>
4993 Are extensible, allowing their abilities to grow in future versions of <jvmti/>
4994 </b>
4995 </li>
4996 </ul>
4997 <p/>
4998 <b>Please use the </b>
4999 <internallink id="Heap"><b>current Heap functions</b></internallink>.
5000 <p/>
5001 <constants id="jvmtiHeapObjectFilter" label="Heap Object Filter Enumeration" kind="enum">
5002 <constant id="JVMTI_HEAP_OBJECT_TAGGED" num="1">
5003 Tagged objects only.
5004 </constant>
5005 <constant id="JVMTI_HEAP_OBJECT_UNTAGGED" num="2">
5006 Untagged objects only.
5007 </constant>
5008 <constant id="JVMTI_HEAP_OBJECT_EITHER" num="3">
5009 Either tagged or untagged objects.
5010 </constant>
5011 </constants>
5012
5013 <constants id="jvmtiHeapRootKind" label="Heap Root Kind Enumeration" kind="enum">
5014 <constant id="JVMTI_HEAP_ROOT_JNI_GLOBAL" num="1">
5015 JNI global reference.
5016 </constant>
5017 <constant id="JVMTI_HEAP_ROOT_SYSTEM_CLASS" num="2">
5018 System class.
5019 </constant>
5020 <constant id="JVMTI_HEAP_ROOT_MONITOR" num="3">
5021 Monitor.
5022 </constant>
5023 <constant id="JVMTI_HEAP_ROOT_STACK_LOCAL" num="4">
5024 Stack local.
5025 </constant>
5026 <constant id="JVMTI_HEAP_ROOT_JNI_LOCAL" num="5">
5027 JNI local reference.
5028 </constant>
5029 <constant id="JVMTI_HEAP_ROOT_THREAD" num="6">
5030 Thread.
5031 </constant>
5032 <constant id="JVMTI_HEAP_ROOT_OTHER" num="7">
5033 Other.
5034 </constant>
5035 </constants>
5036
5037 <constants id="jvmtiObjectReferenceKind" label="Object Reference Enumeration" kind="enum">
5038 <constant id="JVMTI_REFERENCE_CLASS" num="1">
5039 Reference from an object to its class.
5040 </constant>
5041 <constant id="JVMTI_REFERENCE_FIELD" num="2">
5042 Reference from an object to the value of one of its instance fields.
5043 For references of this kind the <code>referrer_index</code>
5044 parameter to the <internallink id="jvmtiObjectReferenceCallback">
5045 jvmtiObjectReferenceCallback</internallink> is the index of the
5046 the instance field. The index is based on the order of all the
5047 object's fields. This includes all fields of the directly declared
5048 static and instance fields in the class, and includes all fields (both
5049 public and private) fields declared in superclasses and superinterfaces.
5050 The index is thus calculated by summing the index of the field in the directly
5051 declared class (see <functionlink id="GetClassFields"/>), with the total
5052 number of fields (both public and private) declared in all superclasses
5053 and superinterfaces. The index starts at zero.
5054 </constant>
5055 <constant id="JVMTI_REFERENCE_ARRAY_ELEMENT" num="3">
5056 Reference from an array to one of its elements.
5057 For references of this kind the <code>referrer_index</code>
5058 parameter to the <internallink id="jvmtiObjectReferenceCallback">
5059 jvmtiObjectReferenceCallback</internallink> is the array index.
5060 </constant>
5061 <constant id="JVMTI_REFERENCE_CLASS_LOADER" num="4">
5062 Reference from a class to its class loader.
5063 </constant>
5064 <constant id="JVMTI_REFERENCE_SIGNERS" num="5">
5065 Reference from a class to its signers array.
5066 </constant>
5067 <constant id="JVMTI_REFERENCE_PROTECTION_DOMAIN" num="6">
5068 Reference from a class to its protection domain.
5069 </constant>
5070 <constant id="JVMTI_REFERENCE_INTERFACE" num="7">
5071 Reference from a class to one of its interfaces.
5072 </constant>
5073 <constant id="JVMTI_REFERENCE_STATIC_FIELD" num="8">
5074 Reference from a class to the value of one of its static fields.
5075 For references of this kind the <code>referrer_index</code>
5076 parameter to the <internallink id="jvmtiObjectReferenceCallback">
5077 jvmtiObjectReferenceCallback</internallink> is the index of the
5078 the static field. The index is based on the order of all the
5079 object's fields. This includes all fields of the directly declared
5080 static and instance fields in the class, and includes all fields (both
5081 public and private) fields declared in superclasses and superinterfaces.
5082 The index is thus calculated by summing the index of the field in the directly
5083 declared class (see <functionlink id="GetClassFields"/>), with the total
5084 number of fields (both public and private) declared in all superclasses
5085 and superinterfaces. The index starts at zero.
5086 Note: this definition differs from that in the <jvmti/> 1.0 Specification.
5087 <rationale>No known implementations used the 1.0 definition.</rationale>
5088 </constant>
5089 <constant id="JVMTI_REFERENCE_CONSTANT_POOL" num="9">
5090 Reference from a class to a resolved entry in the constant pool.
5091 For references of this kind the <code>referrer_index</code>
5092 parameter to the <internallink id="jvmtiObjectReferenceCallback">
5093 jvmtiObjectReferenceCallback</internallink> is the index into
5094 constant pool table of the class, starting at 1. See
5095 <vmspec chapter="4.4"/>.
5096 </constant>
5097 </constants>
5098
5099 <constants id="jvmtiIterationControl" label="Iteration Control Enumeration" kind="enum">
5100 <constant id="JVMTI_ITERATION_CONTINUE" num="1">
5101 Continue the iteration.
5102 If this is a reference iteration, follow the references of this object.
5103 </constant>
5104 <constant id="JVMTI_ITERATION_IGNORE" num="2">
5105 Continue the iteration.
5106 If this is a reference iteration, ignore the references of this object.
5107 </constant>
5108 <constant id="JVMTI_ITERATION_ABORT" num="0">
5109 Abort the iteration.
5110 </constant>
5111 </constants>
5112 </intro>
5113
5114 <callback id="jvmtiHeapObjectCallback">
5115 <enum>jvmtiIterationControl</enum>
5116 <synopsis>Heap Object Callback</synopsis>
5117 <description>
5118 Agent supplied callback function.
5119 Describes (but does not pass in) an object in the heap.
5120 <p/>
5121 Return value should be <code>JVMTI_ITERATION_CONTINUE</code> to continue iteration,
5122 or <code>JVMTI_ITERATION_ABORT</code> to stop iteration.
5123 <p/>
5124 See the <internallink id="heapCallbacks">heap callback
5125 function restrictions</internallink>.
5126 </description>
5127 <parameters>
5128 <param id="class_tag">
5129 <jlong/>
5130 <description>
5131 The tag of the class of object (zero if the class is not tagged).
5132 If the object represents a runtime class,
5133 the <code>class_tag</code> is the tag
5134 associated with <code>java.lang.Class</code>
5135 (zero if <code>java.lang.Class</code> is not tagged).
5136 </description>
5137 </param>
5138 <param id="size">
5139 <jlong/>
5140 <description>
5141 Size of the object (in bytes). See <functionlink id="GetObjectSize"/>.
5142 </description>
5143 </param>
5144 <param id="tag_ptr">
5145 <outptr><jlong/></outptr>
5146 <description>
5147 The object tag value, or zero if the object is not tagged.
5148 To set the tag value to be associated with the object
5149 the agent sets the <code>jlong</code> pointed to by the parameter.
5150 </description>
5151 </param>
5152 <param id="user_data">
5153 <outptr><void/></outptr>
5154 <description>
5155 The user supplied data that was passed into the iteration function.
5156 </description>
5157 </param>
5158 </parameters>
5159 </callback>
5160
5161 <callback id="jvmtiHeapRootCallback">
5162 <enum>jvmtiIterationControl</enum>
5163 <synopsis>Heap Root Object Callback</synopsis>
5164 <description>
5165 Agent supplied callback function.
5166 Describes (but does not pass in) an object that is a root for the purposes
5167 of garbage collection.
5168 <p/>
5169 Return value should be <code>JVMTI_ITERATION_CONTINUE</code> to continue iteration,
5170 <code>JVMTI_ITERATION_IGNORE</code> to continue iteration without pursuing
5171 references from referree object or <code>JVMTI_ITERATION_ABORT</code> to stop iteration.
5172 <p/>
5173 See the <internallink id="heapCallbacks">heap callback
5174 function restrictions</internallink>.
5175 </description>
5176 <parameters>
5177 <param id="root_kind">
5178 <enum>jvmtiHeapRootKind</enum>
5179 <description>
5180 The kind of heap root.
5181 </description>
5182 </param>
5183 <param id="class_tag">
5184 <jlong/>
5185 <description>
5186 The tag of the class of object (zero if the class is not tagged).
5187 If the object represents a runtime class, the <code>class_tag</code> is the tag
5188 associated with <code>java.lang.Class</code>
5189 (zero if <code>java.lang.Class</code> is not tagged).
5190 </description>
5191 </param>
5192 <param id="size">
5193 <jlong/>
5194 <description>
5195 Size of the object (in bytes). See <functionlink id="GetObjectSize"/>.
5196 </description>
5197 </param>
5198 <param id="tag_ptr">
5199 <outptr><jlong/></outptr>
5200 <description>
5201 The object tag value, or zero if the object is not tagged.
5202 To set the tag value to be associated with the object
5203 the agent sets the <code>jlong</code> pointed to by the parameter.
5204 </description>
5205 </param>
5206 <param id="user_data">
5207 <outptr><void/></outptr>
5208 <description>
5209 The user supplied data that was passed into the iteration function.
5210 </description>
5211 </param>
5212 </parameters>
5213 </callback>
5214
5215 <callback id="jvmtiStackReferenceCallback">
5216 <enum>jvmtiIterationControl</enum>
5217 <synopsis>Stack Reference Object Callback</synopsis>
5218 <description>
5219 Agent supplied callback function.
5220 Describes (but does not pass in) an object on the stack that is a root for
5221 the purposes of garbage collection.
5222 <p/>
5223 Return value should be <code>JVMTI_ITERATION_CONTINUE</code> to continue iteration,
5224 <code>JVMTI_ITERATION_IGNORE</code> to continue iteration without pursuing
5225 references from referree object or <code>JVMTI_ITERATION_ABORT</code> to stop iteration.
5226 <p/>
5227 See the <internallink id="heapCallbacks">heap callback
5228 function restrictions</internallink>.
5229 </description>
5230 <parameters>
5231 <param id="root_kind">
5232 <enum>jvmtiHeapRootKind</enum>
5233 <description>
5234 The kind of root (either <code>JVMTI_HEAP_ROOT_STACK_LOCAL</code> or
5235 <code>JVMTI_HEAP_ROOT_JNI_LOCAL</code>).
5236 </description>
5237 </param>
5238 <param id="class_tag">
5239 <jlong/>
5240 <description>
5241 The tag of the class of object (zero if the class is not tagged).
5242 If the object represents a runtime class, the <code>class_tag</code> is the tag
5243 associated with <code>java.lang.Class</code>
5244 (zero if <code>java.lang.Class</code> is not tagged).
5245 </description>
5246 </param>
5247 <param id="size">
5248 <jlong/>
5249 <description>
5250 Size of the object (in bytes). See <functionlink id="GetObjectSize"/>.
5251 </description>
5252 </param>
5253 <param id="tag_ptr">
5254 <outptr><jlong/></outptr>
5255 <description>
5256 The object tag value, or zero if the object is not tagged.
5257 To set the tag value to be associated with the object
5258 the agent sets the <code>jlong</code> pointed to by the parameter.
5259 </description>
5260 </param>
5261 <param id="thread_tag">
5262 <jlong/>
5263 <description>
5264 The tag of the thread corresponding to this stack, zero if not tagged.
5265 </description>
5266 </param>
5267 <param id="depth">
5268 <jint/>
5269 <description>
5270 The depth of the frame.
5271 </description>
5272 </param>
5273 <param id="method">
5274 <jmethodID/>
5275 <description>
5276 The method executing in this frame.
5277 </description>
5278 </param>
5279 <param id="slot">
5280 <jint/>
5281 <description>
5282 The slot number.
5283 </description>
5284 </param>
5285 <param id="user_data">
5286 <outptr><void/></outptr>
5287 <description>
5288 The user supplied data that was passed into the iteration function.
5289 </description>
5290 </param>
5291 </parameters>
5292 </callback>
5293
5294 <callback id="jvmtiObjectReferenceCallback">
5295 <enum>jvmtiIterationControl</enum>
5296 <synopsis>Object Reference Callback</synopsis>
5297 <description>
5298 Agent supplied callback function.
5299 Describes a reference from an object (the referrer) to another object
5300 (the referree).
5301 <p/>
5302 Return value should be <code>JVMTI_ITERATION_CONTINUE</code> to continue iteration,
5303 <code>JVMTI_ITERATION_IGNORE</code> to continue iteration without pursuing
5304 references from referree object or <code>JVMTI_ITERATION_ABORT</code> to stop iteration.
5305 <p/>
5306 See the <internallink id="heapCallbacks">heap callback
5307 function restrictions</internallink>.
5308 </description>
5309 <parameters>
5310 <param id="reference_kind">
5311 <enum>jvmtiObjectReferenceKind</enum>
5312 <description>
5313 The type of reference.
5314 </description>
5315 </param>
5316 <param id="class_tag">
5317 <jlong/>
5318 <description>
5319 The tag of the class of referree object (zero if the class is not tagged).
5320 If the referree object represents a runtime class,
5321 the <code>class_tag</code> is the tag
5322 associated with <code>java.lang.Class</code>
5323 (zero if <code>java.lang.Class</code> is not tagged).
5324 </description>
5325 </param>
5326 <param id="size">
5327 <jlong/>
5328 <description>
5329 Size of the referree object (in bytes).
5330 See <functionlink id="GetObjectSize"/>.
5331 </description>
5332 </param>
5333 <param id="tag_ptr">
5334 <outptr><jlong/></outptr>
5335 <description>
5336 The referree object tag value, or zero if the object is not
5337 tagged.
5338 To set the tag value to be associated with the object
5339 the agent sets the <code>jlong</code> pointed to by the parameter.
5340 </description>
5341 </param>
5342 <param id="referrer_tag">
5343 <jlong/>
5344 <description>
5345 The tag of the referrer object, or zero if the referrer
5346 object is not tagged.
5347 </description>
5348 </param>
5349 <param id="referrer_index">
5350 <jint/>
5351 <description>
5352 For references of type <code>JVMTI_REFERENCE_FIELD</code> or
5353 <code>JVMTI_REFERENCE_STATIC_FIELD</code> the index
5354 of the field in the referrer object. The index is based on the
5355 order of all the object's fields - see <internallink
5356 id="JVMTI_REFERENCE_FIELD">JVMTI_REFERENCE_FIELD</internallink>
5357 or <internallink
5358 id="JVMTI_REFERENCE_STATIC_FIELD">JVMTI_REFERENCE_STATIC_FIELD
5359 </internallink> for further description.
5360 <p/>
5361 For references of type <code>JVMTI_REFERENCE_ARRAY_ELEMENT</code>
5362 the array index - see <internallink id="JVMTI_REFERENCE_ARRAY_ELEMENT">
5363 JVMTI_REFERENCE_ARRAY_ELEMENT</internallink> for further description.
5364 <p/>
5365 For references of type <code>JVMTI_REFERENCE_CONSTANT_POOL</code>
5366 the index into the constant pool of the class - see
5367 <internallink id="JVMTI_REFERENCE_CONSTANT_POOL">
5368 JVMTI_REFERENCE_CONSTANT_POOL</internallink> for further
5369 description.
5370 <p/>
5371 For references of other kinds the <code>referrer_index</code> is
5372 <code>-1</code>.
5373 </description>
5374 </param>
5375 <param id="user_data">
5376 <outptr><void/></outptr>
5377 <description>
5378 The user supplied data that was passed into the iteration function.
5379 </description>
5380 </param>
5381 </parameters>
5382 </callback>
5383
5384 <function id="IterateOverObjectsReachableFromObject" num="109">
5385 <synopsis>Iterate Over Objects Reachable From Object</synopsis>
5386 <description>
5387 This function iterates over all objects that are directly
5388 and indirectly reachable from the specified object.
5389 For each object <i>A</i> (known
5390 as the referrer) with a reference to object <i>B</i> the specified
5391 callback function is called to describe the object reference.
5392 The callback is called exactly once for each reference from a referrer;
5393 this is true even if there are reference cycles or multiple paths to
5394 the referrer.
5395 There may be more than one reference between a referrer and a referree,
5396 These may be distinguished by the
5397 <datalink id="jvmtiObjectReferenceCallback.reference_kind"></datalink> and
5398 <datalink id="jvmtiObjectReferenceCallback.referrer_index"></datalink>.
5399 The callback for an object will always occur after the callback for
5400 its referrer.
5401 <p/>
5402 See <functionlink id="FollowReferences"/> for the object
5403 references which are reported.
5404 <p/>
5405 During the execution of this function the state of the heap
5406 does not change: no objects are allocated, no objects are
5407 garbage collected, and the state of objects (including
5408 held values) does not change.
5409 As a result, threads executing Java
5410 programming language code, threads attempting to resume the
5411 execution of Java programming language code, and threads
5412 attempting to execute JNI functions are typically stalled.
5413 </description>
5414 <origin>new</origin>
5415 <capabilities>
5416 <required id="can_tag_objects"></required>
5417 </capabilities>
5418 <parameters>
5419 <param id="object">
5420 <jobject/>
5421 <description>
5422 The object
5423 </description>
5424 </param>
5425 <param id="object_reference_callback">
5426 <ptrtype>
5427 <struct>jvmtiObjectReferenceCallback</struct>
5428 </ptrtype>
5429 <description>
5430 The callback to be called to describe each
5431 object reference.
5432 </description>
5433 </param>
5434 <param id="user_data">
5435 <inbuf>
5436 <void/>
5437 <nullok><code>NULL</code> is passed as the user supplied data</nullok>
5438 </inbuf>
5439 <description>
5440 User supplied data to be passed to the callback.
5441 </description>
5442 </param>
5443 </parameters>
5444 <errors>
5445 </errors>
5446 </function>
5447
5448 <function id="IterateOverReachableObjects" num="110">
5449 <synopsis>Iterate Over Reachable Objects</synopsis>
5450 <description>
5451 This function iterates over the root objects and all objects that
5452 are directly and indirectly reachable from the root objects.
5453 The root objects comprise the set of system classes,
5454 JNI globals, references from thread stacks, and other objects used as roots
5455 for the purposes of garbage collection.
5456 <p/>
5457 For each root the <paramlink id="heap_root_callback"></paramlink>
5458 or <paramlink id="stack_ref_callback"></paramlink> callback is called.
5459 An object can be a root object for more than one reason and in that case
5460 the appropriate callback is called for each reason.
5461 <p/>
5462 For each object reference the <paramlink id="object_ref_callback"></paramlink>
5463 callback function is called to describe the object reference.
5464 The callback is called exactly once for each reference from a referrer;
5465 this is true even if there are reference cycles or multiple paths to
5466 the referrer.
5467 There may be more than one reference between a referrer and a referree,
5468 These may be distinguished by the
5469 <datalink id="jvmtiObjectReferenceCallback.reference_kind"></datalink> and
5470 <datalink id="jvmtiObjectReferenceCallback.referrer_index"></datalink>.
5471 The callback for an object will always occur after the callback for
5472 its referrer.
5473 <p/>
5474 See <functionlink id="FollowReferences"/> for the object
5475 references which are reported.
5476 <p/>
5477 Roots are always reported to the profiler before any object references
5478 are reported. In other words, the <paramlink id="object_ref_callback"></paramlink>
5479 callback will not be called until the appropriate callback has been called
5480 for all roots. If the <paramlink id="object_ref_callback"></paramlink> callback is
5481 specified as <code>NULL</code> then this function returns after
5482 reporting the root objects to the profiler.
5483 <p/>
5484 During the execution of this function the state of the heap
5485 does not change: no objects are allocated, no objects are
5486 garbage collected, and the state of objects (including
5487 held values) does not change.
5488 As a result, threads executing Java
5489 programming language code, threads attempting to resume the
5490 execution of Java programming language code, and threads
5491 attempting to execute JNI functions are typically stalled.
5492 </description>
5493 <origin>new</origin>
5494 <capabilities>
5495 <required id="can_tag_objects"></required>
5496 </capabilities>
5497 <parameters>
5498 <param id="heap_root_callback">
5499 <ptrtype>
5500 <struct>jvmtiHeapRootCallback</struct>
5501 <nullok>do not report heap roots</nullok>
5502 </ptrtype>
5503 <description>
5504 The callback function to be called for each heap root of type
5505 <code>JVMTI_HEAP_ROOT_JNI_GLOBAL</code>,
5506 <code>JVMTI_HEAP_ROOT_SYSTEM_CLASS</code>,
5507 <code>JVMTI_HEAP_ROOT_MONITOR</code>,
5508 <code>JVMTI_HEAP_ROOT_THREAD</code>, or
5509 <code>JVMTI_HEAP_ROOT_OTHER</code>.
5510 </description>
5511 </param>
5512 <param id="stack_ref_callback">
5513 <ptrtype>
5514 <struct>jvmtiStackReferenceCallback</struct>
5515 <nullok>do not report stack references</nullok>
5516 </ptrtype>
5517 <description>
5518 The callback function to be called for each heap root of
5519 <code>JVMTI_HEAP_ROOT_STACK_LOCAL</code> or
5520 <code>JVMTI_HEAP_ROOT_JNI_LOCAL</code>.
5521 </description>
5522 </param>
5523 <param id="object_ref_callback">
5524 <ptrtype>
5525 <struct>jvmtiObjectReferenceCallback</struct>
5526 <nullok>do not follow references from the root objects</nullok>
5527 </ptrtype>
5528 <description>
5529 The callback function to be called for each object reference.
5530 </description>
5531 </param>
5532 <param id="user_data">
5533 <inbuf>
5534 <void/>
5535 <nullok><code>NULL</code> is passed as the user supplied data</nullok>
5536 </inbuf>
5537 <description>
5538 User supplied data to be passed to the callback.
5539 </description>
5540 </param>
5541 </parameters>
5542 <errors>
5543 </errors>
5544 </function>
5545
5546 <function id="IterateOverHeap" num="111">
5547 <synopsis>Iterate Over Heap</synopsis>
5548 <description>
5549 Iterate over all objects in the heap. This includes both reachable and
5550 unreachable objects.
5551 <p/>
5552 The <paramlink id="object_filter"></paramlink> parameter indicates the
5553 objects for which the callback function is called. If this parameter
5554 is <code>JVMTI_HEAP_OBJECT_TAGGED</code> then the callback will only be
5555 called for every object that is tagged. If the parameter is
5556 <code>JVMTI_HEAP_OBJECT_UNTAGGED</code> then the callback will only be
5557 for objects that are not tagged. If the parameter
5558 is <code>JVMTI_HEAP_OBJECT_EITHER</code> then the callback will be
5559 called for every object in the heap, irrespective of whether it is
5560 tagged or not.
5561 <p/>
5562 During the execution of this function the state of the heap
5563 does not change: no objects are allocated, no objects are
5564 garbage collected, and the state of objects (including
5565 held values) does not change.
5566 As a result, threads executing Java
5567 programming language code, threads attempting to resume the
5568 execution of Java programming language code, and threads
5569 attempting to execute JNI functions are typically stalled.
5570 </description>
5571 <origin>new</origin>
5572 <capabilities>
5573 <required id="can_tag_objects"></required>
5574 </capabilities>
5575 <parameters>
5576 <param id="object_filter">
5577 <enum>jvmtiHeapObjectFilter</enum>
5578 <description>
5579 Indicates the objects for which the callback function is called.
5580 </description>
5581 </param>
5582 <param id="heap_object_callback">
5583 <ptrtype>
5584 <struct>jvmtiHeapObjectCallback</struct>
5585 </ptrtype>
5586 <description>
5587 The iterator function to be called for each
5588 object matching the <paramlink id="object_filter"/>.
5589 </description>
5590 </param>
5591 <param id="user_data">
5592 <inbuf>
5593 <void/>
5594 <nullok><code>NULL</code> is passed as the user supplied data</nullok>
5595 </inbuf>
5596 <description>
5597 User supplied data to be passed to the callback.
5598 </description>
5599 </param>
5600 </parameters>
5601 <errors>
5602 </errors>
5603 </function>
5604
5605 <function id="IterateOverInstancesOfClass" num="112">
5606 <synopsis>Iterate Over Instances Of Class</synopsis>
5607 <description>
5608 Iterate over all objects in the heap that are instances of the specified class.
5609 This includes direct instances of the specified class and
5610 instances of all subclasses of the specified class.
5611 This includes both reachable and unreachable objects.
5612 <p/>
5613 The <paramlink id="object_filter"></paramlink> parameter indicates the
5614 objects for which the callback function is called. If this parameter
5615 is <code>JVMTI_HEAP_OBJECT_TAGGED</code> then the callback will only be
5616 called for every object that is tagged. If the parameter is
5617 <code>JVMTI_HEAP_OBJECT_UNTAGGED</code> then the callback will only be
5618 called for objects that are not tagged. If the parameter
5619 is <code>JVMTI_HEAP_OBJECT_EITHER</code> then the callback will be
5620 called for every object in the heap, irrespective of whether it is
5621 tagged or not.
5622 <p/>
5623 During the execution of this function the state of the heap
5624 does not change: no objects are allocated, no objects are
5625 garbage collected, and the state of objects (including
5626 held values) does not change.
5627 As a result, threads executing Java
5628 programming language code, threads attempting to resume the
5629 execution of Java programming language code, and threads
5630 attempting to execute JNI functions are typically stalled.
5631 </description>
5632 <origin>new</origin>
5633 <capabilities>
5634 <required id="can_tag_objects"></required>
5635 </capabilities>
5636 <parameters>
5637 <param id="klass">
5638 <jclass/>
5639 <description>
5640 Iterate over objects of this class only.
5641 </description>
5642 </param>
5643 <param id="object_filter">
5644 <enum>jvmtiHeapObjectFilter</enum>
5645 <description>
5646 Indicates the objects for which the callback function is called.
5647 </description>
5648 </param>
5649 <param id="heap_object_callback">
5650 <ptrtype>
5651 <struct>jvmtiHeapObjectCallback</struct>
5652 </ptrtype>
5653 <description>
5654 The iterator function to be called for each
5655 <paramlink id="klass"/> instance matching
5656 the <paramlink id="object_filter"/>.
5657 </description>
5658 </param>
5659 <param id="user_data">
5660 <inbuf>
5661 <void/>
5662 <nullok><code>NULL</code> is passed as the user supplied data</nullok>
5663 </inbuf>
5664 <description>
5665 User supplied data to be passed to the callback.
5666 </description>
5667 </param>
5668 </parameters>
5669 <errors>
5670 </errors>
5671 </function>
5672
5673 </category>
5674
5675 <category id="local" label="Local Variable">
5676
5677 <intro>
5678 These functions are used to retrieve or set the value of a local variable.
5679 The variable is identified by the depth of the frame containing its
5680 value and the variable's slot number within that frame.
5681 The mapping of variables to
5682 slot numbers can be obtained with the function
5683 <functionlink id="GetLocalVariableTable"></functionlink>.
5684 </intro>
5685
5686 <function id="GetLocalObject" num="21">
5687 <synopsis>Get Local Variable - Object</synopsis>
5688 <description>
5689 This function can be used to retrieve the value of a local
5690 variable whose type is <code>Object</code> or a subclass of <code>Object</code>.
5691 </description>
5692 <origin>jvmdi</origin>
5693 <capabilities>
5694 <required id="can_access_local_variables"></required>
5695 </capabilities>
5696 <parameters>
5697 <param id="thread">
5698 <jthread null="current" frame="frame"/>
5699 <description>
5700 The thread of the frame containing the variable's value.
5701 </description>
5702 </param>
5703 <param id="depth">
5704 <jframeID thread="thread"/>
5705 <description>
5706 The depth of the frame containing the variable's value.
5707 </description>
5708 </param>
5709 <param id="slot">
5710 <jint/>
5711 <description>
5712 The variable's slot number.
5713 </description>
5714 </param>
5715 <param id="value_ptr">
5716 <outptr><jobject/></outptr>
5717 <description>
5718 On return, points to the variable's value.
5719 </description>
5720 </param>
5721 </parameters>
5722 <errors>
5723 <error id="JVMTI_ERROR_INVALID_SLOT">
5724 Invalid <code>slot</code>.
5725 </error>
5726 <error id="JVMTI_ERROR_TYPE_MISMATCH">
5727 The variable type is not
5728 <code>Object</code> or a subclass of <code>Object</code>.
5729 </error>
5730 <error id="JVMTI_ERROR_OPAQUE_FRAME">
5731 Not a visible frame
5732 </error>
5733 </errors>
5734 </function>
5735
5736 <function id="GetLocalInstance" num="155" since="1.2">
5737 <synopsis>Get Local Instance</synopsis>
5738 <description>
5739 This function can be used to retrieve the value of the local object
5740 variable at slot 0 (the "<code>this</code>" object) from non-static
5741 frames. This function can retrieve the "<code>this</code>" object from
5742 native method frames, whereas <code>GetLocalObject()</code> would
5743 return <code>JVMTI_ERROR_OPAQUE_FRAME</code> in those cases.
5744 </description>
5745 <origin>new</origin>
5746 <capabilities>
5747 <required id="can_access_local_variables"></required>
5748 </capabilities>
5749 <parameters>
5750 <param id="thread">
5751 <jthread null="current" frame="frame"/>
5752 <description>
5753 The thread of the frame containing the variable's value.
5754 </description>
5755 </param>
5756 <param id="depth">
5757 <jframeID thread="thread"/>
5758 <description>
5759 The depth of the frame containing the variable's value.
5760 </description>
5761 </param>
5762 <param id="value_ptr">
5763 <outptr><jobject/></outptr>
5764 <description>
5765 On return, points to the variable's value.
5766 </description>
5767 </param>
5768 </parameters>
5769 <errors>
5770 <error id="JVMTI_ERROR_INVALID_SLOT">
5771 If the specified frame is a static method frame.
5772 </error>
5773 </errors>
5774 </function>
5775 <function id="GetLocalInt" num="22">
5776 <synopsis>Get Local Variable - Int</synopsis>
5777 <description>
5778 This function can be used to retrieve the value of a local
5779 variable whose type is <code>int</code>,
5780 <code>short</code>, <code>char</code>, <code>byte</code>, or
5781 <code>boolean</code>.
5782 </description>
5783 <origin>jvmdi</origin>
5784 <capabilities>
5785 <required id="can_access_local_variables"></required>
5786 </capabilities>
5787 <parameters>
5788 <param id="thread">
5789 <jthread null="current" frame="frame"/>
5790 <description>
5791 The thread of the frame containing the variable's value.
5792 </description>
5793 </param>
5794 <param id="depth">
5795 <jframeID thread="thread"/>
5796 <description>
5797 The depth of the frame containing the variable's value.
5798 </description>
5799 </param>
5800 <param id="slot">
5801 <jint/>
5802 <description>
5803 The variable's slot number.
5804 </description>
5805 </param>
5806 <param id="value_ptr">
5807 <outptr><jint/></outptr>
5808 <description>
5809 On return, points to the variable's value.
5810 </description>
5811 </param>
5812 </parameters>
5813 <errors>
5814 <error id="JVMTI_ERROR_INVALID_SLOT">
5815 Invalid <code>slot</code>.
5816 </error>
5817 <error id="JVMTI_ERROR_TYPE_MISMATCH">
5818 The variable type is not
5819 <code>int</code>, <code>short</code>,
5820 <code>char</code>, <code>byte</code>, or
5821 <code>boolean</code>.
5822 </error>
5823 <error id="JVMTI_ERROR_OPAQUE_FRAME">
5824 Not a visible frame
5825 </error>
5826 </errors>
5827 </function>
5828
5829 <function id="GetLocalLong" num="23">
5830 <synopsis>Get Local Variable - Long</synopsis>
5831 <description>
5832 This function can be used to retrieve the value of a local
5833 variable whose type is <code>long</code>.
5834 </description>
5835 <origin>jvmdi</origin>
5836 <capabilities>
5837 <required id="can_access_local_variables"></required>
5838 </capabilities>
5839 <parameters>
5840 <param id="thread">
5841 <jthread null="current" frame="frame"/>
5842 <description>
5843 The thread of the frame containing the variable's value.
5844 </description>
5845 </param>
5846 <param id="depth">
5847 <jframeID thread="thread"/>
5848 <description>
5849 The depth of the frame containing the variable's value.
5850 </description>
5851 </param>
5852 <param id="slot">
5853 <jint/>
5854 <description>
5855 The variable's slot number.
5856 </description>
5857 </param>
5858 <param id="value_ptr">
5859 <outptr><jlong/></outptr>
5860 <description>
5861 On return, points to the variable's value.
5862 </description>
5863 </param>
5864 </parameters>
5865 <errors>
5866 <error id="JVMTI_ERROR_INVALID_SLOT">
5867 Invalid <code>slot</code>.
5868 </error>
5869 <error id="JVMTI_ERROR_TYPE_MISMATCH">
5870 The variable type is not <code>long</code>.
5871 </error>
5872 <error id="JVMTI_ERROR_OPAQUE_FRAME">
5873 Not a visible frame
5874 </error>
5875 </errors>
5876 </function>
5877
5878 <function id="GetLocalFloat" num="24">
5879 <synopsis>Get Local Variable - Float</synopsis>
5880 <description>
5881 This function can be used to retrieve the value of a local
5882 variable whose type is <code>float</code>.
5883 </description>
5884 <origin>jvmdi</origin>
5885 <capabilities>
5886 <required id="can_access_local_variables"></required>
5887 </capabilities>
5888 <parameters>
5889 <param id="thread">
5890 <jthread null="current" frame="frame"/>
5891 <description>
5892 The thread of the frame containing the variable's value.
5893 </description>
5894 </param>
5895 <param id="depth">
5896 <jframeID thread="thread"/>
5897 <description>
5898 The depth of the frame containing the variable's value.
5899 </description>
5900 </param>
5901 <param id="slot">
5902 <jint/>
5903 <description>
5904 The variable's slot number.
5905 </description>
5906 </param>
5907 <param id="value_ptr">
5908 <outptr><jfloat/></outptr>
5909 <description>
5910 On return, points to the variable's value.
5911 </description>
5912 </param>
5913 </parameters>
5914 <errors>
5915 <error id="JVMTI_ERROR_INVALID_SLOT">
5916 Invalid <code>slot</code>.
5917 </error>
5918 <error id="JVMTI_ERROR_TYPE_MISMATCH">
5919 The variable type is not <code>float</code>.
5920 </error>
5921 <error id="JVMTI_ERROR_OPAQUE_FRAME">
5922 Not a visible frame
5923 </error>
5924 </errors>
5925 </function>
5926
5927 <function id="GetLocalDouble" num="25">
5928 <synopsis>Get Local Variable - Double</synopsis>
5929 <description>
5930 This function can be used to retrieve the value of a local
5931 variable whose type is <code>long</code>.
5932 </description>
5933 <origin>jvmdi</origin>
5934 <capabilities>
5935 <required id="can_access_local_variables"></required>
5936 </capabilities>
5937 <parameters>
5938 <param id="thread">
5939 <jthread null="current" frame="frame"/>
5940 <description>
5941 The thread of the frame containing the variable's value.
5942 </description>
5943 </param>
5944 <param id="depth">
5945 <jframeID thread="thread"/>
5946 <description>
5947 The depth of the frame containing the variable's value.
5948 </description>
5949 </param>
5950 <param id="slot">
5951 <jint/>
5952 <description>
5953 The variable's slot number.
5954 </description>
5955 </param>
5956 <param id="value_ptr">
5957 <outptr><jdouble/></outptr>
5958 <description>
5959 On return, points to the variable's value.
5960 </description>
5961 </param>
5962 </parameters>
5963 <errors>
5964 <error id="JVMTI_ERROR_INVALID_SLOT">
5965 Invalid <code>slot</code>.
5966 </error>
5967 <error id="JVMTI_ERROR_TYPE_MISMATCH">
5968 The variable type is not <code>double</code>.
5969 </error>
5970 <error id="JVMTI_ERROR_OPAQUE_FRAME">
5971 Not a visible frame
5972 </error>
5973 </errors>
5974 </function>
5975
5976 <function id="SetLocalObject" num="26">
5977 <synopsis>Set Local Variable - Object</synopsis>
5978 <description>
5979 This function can be used to set the value of a local
5980 variable whose type is <code>Object</code> or a subclass of <code>Object</code>.
5981 </description>
5982 <origin>jvmdi</origin>
5983 <capabilities>
5984 <required id="can_access_local_variables"></required>
5985 </capabilities>
5986 <parameters>
5987 <param id="thread">
5988 <jthread null="current" frame="frame"/>
5989 <description>
5990 The thread of the frame containing the variable's value.
5991 </description>
5992 </param>
5993 <param id="depth">
5994 <jframeID thread="thread"/>
5995 <description>
5996 The depth of the frame containing the variable's value.
5997 </description>
5998 </param>
5999 <param id="slot">
6000 <jint/>
6001 <description>
6002 The variable's slot number.
6003 </description>
6004 </param>
6005 <param id="value">
6006 <jobject/>
6007 <description>
6008 The new value for the variable.
6009 </description>
6010 </param>
6011 </parameters>
6012 <errors>
6013 <error id="JVMTI_ERROR_INVALID_SLOT">
6014 Invalid <code>slot</code>.
6015 </error>
6016 <error id="JVMTI_ERROR_TYPE_MISMATCH">
6017 The variable type is not
6018 <code>Object</code> or a subclass of <code>Object</code>.
6019 </error>
6020 <error id="JVMTI_ERROR_TYPE_MISMATCH">
6021 The supplied <paramlink id="value"/> is not compatible
6022 with the variable type.
6023 </error>
6024 <error id="JVMTI_ERROR_OPAQUE_FRAME">
6025 Not a visible frame
6026 </error>
6027 </errors>
6028 </function>
6029
6030 <function id="SetLocalInt" num="27">
6031 <synopsis>Set Local Variable - Int</synopsis>
6032 <description>
6033 This function can be used to set the value of a local
6034 variable whose type is <code>int</code>,
6035 <code>short</code>, <code>char</code>, <code>byte</code>, or
6036 <code>boolean</code>.
6037 </description>
6038 <origin>jvmdi</origin>
6039 <capabilities>
6040 <required id="can_access_local_variables"></required>
6041 </capabilities>
6042 <parameters>
6043 <param id="thread">
6044 <jthread null="current" frame="frame"/>
6045 <description>
6046 The thread of the frame containing the variable's value.
6047 </description>
6048 </param>
6049 <param id="depth">
6050 <jframeID thread="thread"/>
6051 <description>
6052 The depth of the frame containing the variable's value.
6053 </description>
6054 </param>
6055 <param id="slot">
6056 <jint/>
6057 <description>
6058 The variable's slot number.
6059 </description>
6060 </param>
6061 <param id="value">
6062 <jint/>
6063 <description>
6064 The new value for the variable.
6065 </description>
6066 </param>
6067 </parameters>
6068 <errors>
6069 <error id="JVMTI_ERROR_INVALID_SLOT">
6070 Invalid <code>slot</code>.
6071 </error>
6072 <error id="JVMTI_ERROR_TYPE_MISMATCH">
6073 The variable type is not
6074 <code>int</code>, <code>short</code>,
6075 <code>char</code>, <code>byte</code>, or
6076 <code>boolean</code>.
6077 </error>
6078 <error id="JVMTI_ERROR_OPAQUE_FRAME">
6079 Not a visible frame
6080 </error>
6081 </errors>
6082 </function>
6083
6084 <function id="SetLocalLong" num="28">
6085 <synopsis>Set Local Variable - Long</synopsis>
6086 <description>
6087 This function can be used to set the value of a local
6088 variable whose type is <code>long</code>.
6089 </description>
6090 <origin>jvmdi</origin>
6091 <capabilities>
6092 <required id="can_access_local_variables"></required>
6093 </capabilities>
6094 <parameters>
6095 <param id="thread">
6096 <jthread null="current" frame="frame"/>
6097 <description>
6098 The thread of the frame containing the variable's value.
6099 </description>
6100 </param>
6101 <param id="depth">
6102 <jframeID thread="thread"/>
6103 <description>
6104 The depth of the frame containing the variable's value.
6105 </description>
6106 </param>
6107 <param id="slot">
6108 <jint/>
6109 <description>
6110 The variable's slot number.
6111 </description>
6112 </param>
6113 <param id="value">
6114 <jlong/>
6115 <description>
6116 The new value for the variable.
6117 </description>
6118 </param>
6119 </parameters>
6120 <errors>
6121 <error id="JVMTI_ERROR_INVALID_SLOT">
6122 Invalid <code>slot</code>.
6123 </error>
6124 <error id="JVMTI_ERROR_TYPE_MISMATCH">
6125 The variable type is not <code>long</code>.
6126 </error>
6127 <error id="JVMTI_ERROR_OPAQUE_FRAME">
6128 Not a visible frame
6129 </error>
6130 </errors>
6131 </function>
6132
6133 <function id="SetLocalFloat" num="29">
6134 <synopsis>Set Local Variable - Float</synopsis>
6135 <description>
6136 This function can be used to set the value of a local
6137 variable whose type is <code>float</code>.
6138 </description>
6139 <origin>jvmdi</origin>
6140 <capabilities>
6141 <required id="can_access_local_variables"></required>
6142 </capabilities>
6143 <parameters>
6144 <param id="thread">
6145 <jthread null="current" frame="frame"/>
6146 <description>
6147 The thread of the frame containing the variable's value.
6148 </description>
6149 </param>
6150 <param id="depth">
6151 <jframeID thread="thread"/>
6152 <description>
6153 The depth of the frame containing the variable's value.
6154 </description>
6155 </param>
6156 <param id="slot">
6157 <jint/>
6158 <description>
6159 The variable's slot number.
6160 </description>
6161 </param>
6162 <param id="value">
6163 <jfloat/>
6164 <description>
6165 The new value for the variable.
6166 </description>
6167 </param>
6168 </parameters>
6169 <errors>
6170 <error id="JVMTI_ERROR_INVALID_SLOT">
6171 Invalid <code>slot</code>.
6172 </error>
6173 <error id="JVMTI_ERROR_TYPE_MISMATCH">
6174 The variable type is not <code>float</code>.
6175 </error>
6176 <error id="JVMTI_ERROR_OPAQUE_FRAME">
6177 Not a visible frame
6178 </error>
6179 </errors>
6180 </function>
6181
6182 <function id="SetLocalDouble" num="30">
6183 <synopsis>Set Local Variable - Double</synopsis>
6184 <description>
6185 This function can be used to set the value of a local
6186 variable whose type is <code>double</code>.
6187 </description>
6188 <origin>jvmdi</origin>
6189 <capabilities>
6190 <required id="can_access_local_variables"></required>
6191 </capabilities>
6192 <parameters>
6193 <param id="thread">
6194 <jthread null="current" frame="frame"/>
6195 <description>
6196 The thread of the frame containing the variable's value.
6197 </description>
6198 </param>
6199 <param id="depth">
6200 <jframeID thread="thread"/>
6201 <description>
6202 The depth of the frame containing the variable's value.
6203 </description>
6204 </param>
6205 <param id="slot">
6206 <jint/>
6207 <description>
6208 The variable's slot number.
6209 </description>
6210 </param>
6211 <param id="value">
6212 <jdouble/>
6213 <description>
6214 The new value for the variable.
6215 </description>
6216 </param>
6217 </parameters>
6218 <errors>
6219 <error id="JVMTI_ERROR_INVALID_SLOT">
6220 Invalid <code>slot</code>.
6221 </error>
6222 <error id="JVMTI_ERROR_TYPE_MISMATCH">
6223 The variable type is not <code>double</code>.
6224 </error>
6225 <error id="JVMTI_ERROR_OPAQUE_FRAME">
6226 Not a visible frame
6227 </error>
6228 </errors>
6229 </function>
6230 </category>
6231
6232 <category id="breakpointCategory" label="Breakpoint">
6233
6234 <intro>
6235 </intro>
6236
6237 <function id="SetBreakpoint" num="38">
6238 <synopsis>Set Breakpoint</synopsis>
6239 <description>
6240 Set a breakpoint at the instruction indicated by
6241 <code>method</code> and <code>location</code>.
6242 An instruction can only have one breakpoint.
6243 <p/>
6244 Whenever the designated instruction is about to be executed, a
6245 <eventlink id="Breakpoint"></eventlink> event is generated.
6246 </description>
6247 <origin>jvmdi</origin>
6248 <capabilities>
6249 <required id="can_generate_breakpoint_events"></required>
6250 </capabilities>
6251 <parameters>
6252 <param id="klass">
6253 <jclass method="method"/>
6254 <description>
6255 The class in which to set the breakpoint
6256 </description>
6257 </param>
6258 <param id="method">
6259 <jmethodID class="klass"/>
6260 <description>
6261 The method in which to set the breakpoint
6262 </description>
6263 </param>
6264 <param id="location">
6265 <jlocation/>
6266 <description>
6267 the index of the instruction at which to set the breakpoint
6268
6269 </description>
6270 </param>
6271 </parameters>
6272 <errors>
6273 <error id="JVMTI_ERROR_DUPLICATE">
6274 The designated bytecode already has a breakpoint.
6275 </error>
6276 </errors>
6277 </function>
6278
6279 <function id="ClearBreakpoint" num="39">
6280 <synopsis>Clear Breakpoint</synopsis>
6281 <description>
6282 Clear the breakpoint at the bytecode indicated by
6283 <code>method</code> and <code>location</code>.
6284 </description>
6285 <origin>jvmdi</origin>
6286 <capabilities>
6287 <required id="can_generate_breakpoint_events"></required>
6288 </capabilities>
6289 <parameters>
6290 <param id="klass">
6291 <jclass method="method"/>
6292 <description>
6293 The class in which to clear the breakpoint
6294 </description>
6295 </param>
6296 <param id="method">
6297 <jmethodID class="klass"/>
6298 <description>
6299 The method in which to clear the breakpoint
6300 </description>
6301 </param>
6302 <param id="location">
6303 <jlocation/>
6304 <description>
6305 the index of the instruction at which to clear the breakpoint
6306 </description>
6307 </param>
6308 </parameters>
6309 <errors>
6310 <error id="JVMTI_ERROR_NOT_FOUND">
6311 There's no breakpoint at the designated bytecode.
6312 </error>
6313 </errors>
6314 </function>
6315
6316 </category>
6317
6318 <category id="fieldWatch" label="Watched Field">
6319
6320 <intro>
6321 </intro>
6322
6323 <function id="SetFieldAccessWatch" num="41">
6324 <synopsis>Set Field Access Watch</synopsis>
6325 <description>
6326 Generate a <eventlink id="FieldAccess"></eventlink> event
6327 when the field specified
6328 by <code>klass</code> and
6329 <code>field</code> is about to be accessed.
6330 An event will be generated for each access of the field
6331 until it is canceled with
6332 <functionlink id="ClearFieldAccessWatch"></functionlink>.
6333 Field accesses from Java programming language code or from JNI code are watched,
6334 fields modified by other means are not watched.
6335 Note that <jvmti/> users should be aware that their own field accesses
6336 will trigger the watch.
6337 A field can only have one field access watch set.
6338 Modification of a field is not considered an access--use
6339 <functionlink id="SetFieldModificationWatch"></functionlink>
6340 to monitor modifications.
6341 </description>
6342 <origin>jvmdi</origin>
6343 <capabilities>
6344 <required id="can_generate_field_access_events"></required>
6345 </capabilities>
6346 <parameters>
6347 <param id="klass">
6348 <jclass field="field"/>
6349 <description>
6350 The class containing the field to watch
6351 </description>
6352 </param>
6353 <param id="field">
6354 <jfieldID class="klass"/>
6355 <description>
6356 The field to watch
6357
6358 </description>
6359 </param>
6360 </parameters>
6361 <errors>
6362 <error id="JVMTI_ERROR_DUPLICATE">
6363 The designated field is already being watched for accesses.
6364 </error>
6365 </errors>
6366 </function>
6367
6368 <function id="ClearFieldAccessWatch" num="42">
6369 <synopsis>Clear Field Access Watch</synopsis>
6370 <description>
6371 Cancel a field access watch previously set by
6372 <functionlink id="SetFieldAccessWatch"></functionlink>, on the
6373 field specified
6374 by <code>klass</code> and
6375 <code>field</code>.
6376 </description>
6377 <origin>jvmdi</origin>
6378 <capabilities>
6379 <required id="can_generate_field_access_events"></required>
6380 </capabilities>
6381 <parameters>
6382 <param id="klass">
6383 <jclass field="field"/>
6384 <description>
6385 The class containing the field to watch
6386 </description>
6387 </param>
6388 <param id="field">
6389 <jfieldID class="klass"/>
6390 <description>
6391 The field to watch
6392
6393 </description>
6394 </param>
6395 </parameters>
6396 <errors>
6397 <error id="JVMTI_ERROR_NOT_FOUND">
6398 The designated field is not being watched for accesses.
6399 </error>
6400 </errors>
6401 </function>
6402
6403 <function id="SetFieldModificationWatch" num="43">
6404 <synopsis>Set Field Modification Watch</synopsis>
6405 <description>
6406 Generate a <eventlink id="FieldModification"></eventlink> event
6407 when the field specified
6408 by <code>klass</code> and
6409 <code>field</code> is about to be modified.
6410 An event will be generated for each modification of the field
6411 until it is canceled with
6412 <functionlink id="ClearFieldModificationWatch"></functionlink>.
6413 Field modifications from Java programming language code or from JNI code are watched,
6414 fields modified by other means are not watched.
6415 Note that <jvmti/> users should be aware that their own field modifications
6416 will trigger the watch.
6417 A field can only have one field modification watch set.
6418 </description>
6419 <origin>jvmdi</origin>
6420 <capabilities>
6421 <required id="can_generate_field_modification_events"></required>
6422 </capabilities>
6423 <parameters>
6424 <param id="klass">
6425 <jclass field="field"/>
6426 <description>
6427 The class containing the field to watch
6428 </description>
6429 </param>
6430 <param id="field">
6431 <jfieldID class="klass"/>
6432 <description>
6433 The field to watch
6434
6435 </description>
6436 </param>
6437 </parameters>
6438 <errors>
6439 <error id="JVMTI_ERROR_DUPLICATE">
6440 The designated field is already being watched for modifications.
6441 </error>
6442 </errors>
6443 </function>
6444
6445 <function id="ClearFieldModificationWatch" num="44">
6446 <synopsis>Clear Field Modification Watch</synopsis>
6447 <description>
6448
6449 Cancel a field modification watch previously set by
6450 <functionlink id="SetFieldModificationWatch"></functionlink>, on the
6451 field specified
6452 by <code>klass</code> and
6453 <code>field</code>.
6454 </description>
6455 <origin>jvmdi</origin>
6456 <capabilities>
6457 <required id="can_generate_field_modification_events"></required>
6458 </capabilities>
6459 <parameters>
6460 <param id="klass">
6461 <jclass field="field"/>
6462 <description>
6463 The class containing the field to watch
6464 </description>
6465 </param>
6466 <param id="field">
6467 <jfieldID class="klass"/>
6468 <description>
6469 The field to watch
6470
6471 </description>
6472 </param>
6473 </parameters>
6474 <errors>
6475 <error id="JVMTI_ERROR_NOT_FOUND">
6476 The designated field is not being watched for modifications.
6477 </error>
6478 </errors>
6479 </function>
6480 </category>
6481
6482 <category id="module" label="Module">
6483
6484 <intro>
6485 </intro>
6486
6487 <function id="GetAllModules" num="3" since="9">
6488 <synopsis>Get All Modules</synopsis>
6489 <description>
6490 Return an array of all modules loaded in the virtual machine.
6491 The array includes the unnamed module for each class loader.
6492 The number of modules in the array is returned via
6493 <code>module_count_ptr</code>, and the array itself via
6494 <code>modules_ptr</code>.
6495 <p/>
6496 </description>
6497 <origin>new</origin>
6498 <capabilities>
6499 </capabilities>
6500 <parameters>
6501 <param id="module_count_ptr">
6502 <outptr><jint/></outptr>
6503 <description>
6504 On return, points to the number of returned modules.
6505 </description>
6506 </param>
6507 <param id="modules_ptr">
6508 <allocbuf outcount="module_count_ptr"><jobject/></allocbuf>
6509 <description>
6510 On return, points to an array of references, one
6511 for each module.
6512 </description>
6513 </param>
6514 </parameters>
6515 <errors>
6516 </errors>
6517 </function>
6518
6519 <function id="GetNamedModule" num="40" since="9">
6520 <synopsis>Get Named Module</synopsis>
6521 <description>
6522 Return the <code>java.lang.Module</code> object for a named
6523 module defined to a class loader that contains a given package.
6524 The module is returned via <code>module_ptr</code>.
6525 <p/>
6526 If a named module is defined to the class loader and it
6527 contains the package then that named module is returned,
6528 otherwise <code>NULL</code> is returned.
6529 <p/>
6530 </description>
6531 <origin>new</origin>
6532 <capabilities>
6533 </capabilities>
6534 <parameters>
6535 <param id="class_loader">
6536 <ptrtype>
6537 <jobject/>
6538 <nullok>the bootstrap loader is assumed</nullok>
6539 </ptrtype>
6540 <description>
6541 A class loader.
6542 If the <code>class_loader</code> is not <code>NULL</code>
6543 or a subclass of <code>java.lang.ClassLoader</code>
6544 this function returns
6545 <errorlink id="JVMTI_ERROR_ILLEGAL_ARGUMENT"></errorlink>.
6546 </description>
6547 </param>
6548 <param id="package_name">
6549 <inbuf><char/></inbuf>
6550 <description>
6551 The name of the package, encoded as a
6552 <internallink id="mUTF">modified UTF-8</internallink> string.
6553 The package name is in internal form (JVMS 4.2.1);
6554 identifiers are separated by forward slashes rather than periods.
6555 </description>
6556 </param>
6557 <param id="module_ptr">
6558 <outptr><jobject/></outptr>
6559 <description>
6560 On return, points to a <code>java.lang.Module</code> object
6561 or points to <code>NULL</code>.
6562 </description>
6563 </param>
6564 </parameters>
6565 <errors>
6566 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
6567 If class loader is not <code>NULL</code> and is not a class loader object.
6568 </error>
6569 </errors>
6570 </function>
6571
6572 <function id="AddModuleReads" num="94" since="9">
6573 <synopsis>Add Module Reads</synopsis>
6574 <description>
6575 Update a module to read another module. This function is a no-op
6576 when <paramlink id="module"></paramlink> is an unnamed module.
6577 This function facilitates the instrumentation of code
6578 in named modules where that instrumentation requires
6579 expanding the set of modules that a module reads.
6580 </description>
6581 <origin>new</origin>
6582 <capabilities>
6583 </capabilities>
6584 <parameters>
6585 <param id="module">
6586 <ptrtype><jobject/></ptrtype>
6587 <description>
6588 The module to update.
6589 </description>
6590 </param>
6591 <param id="to_module">
6592 <ptrtype><jobject/></ptrtype>
6593 <description>
6594 The additional module to read.
6595 </description>
6596 </param>
6597 </parameters>
6598 <errors>
6599 <error id="JVMTI_ERROR_INVALID_MODULE">
6600 If <paramlink id="module"></paramlink> is not a module object.
6601 </error>
6602 <error id="JVMTI_ERROR_INVALID_MODULE">
6603 If <paramlink id="to_module"></paramlink> is not a module object.
6604 </error>
6605 <error id="JVMTI_ERROR_UNMODIFIABLE_MODULE">
6606 if the module cannot be modified.
6607 See <functionlink id="IsModifiableModule"/>.
6608 </error>
6609 </errors>
6610 </function>
6611
6612 <function id="AddModuleExports" num="95" since="9">
6613 <synopsis>Add Module Exports</synopsis>
6614 <description>
6615 Update a module to export a package to another module.
6616 This function is a no-op when <paramlink id="module"></paramlink>
6617 is an unnamed module or an open module.
6618 This function facilitates the instrumentation of code
6619 in named modules where that instrumentation requires
6620 expanding the set of packages that a module exports.
6621 </description>
6622 <origin>new</origin>
6623 <capabilities>
6624 </capabilities>
6625 <parameters>
6626 <param id="module">
6627 <ptrtype><jobject/></ptrtype>
6628 <description>
6629 The module to update.
6630 </description>
6631 </param>
6632 <param id="pkg_name">
6633 <inbuf><char/></inbuf>
6634 <description>
6635 The exported package name.
6636 </description>
6637 </param>
6638 <param id="to_module">
6639 <ptrtype><jobject/></ptrtype>
6640 <description>
6641 The module the package is exported to.
6642 If the <code>to_module</code> is not a subclass of
6643 <code>java.lang.Module</code> this function returns
6644 <errorlink id="JVMTI_ERROR_INVALID_MODULE"></errorlink>.
6645 </description>
6646 </param>
6647 </parameters>
6648 <errors>
6649 <error id="JVMTI_ERROR_INVALID_MODULE">
6650 If <paramlink id="module"></paramlink> is not a module object.
6651 </error>
6652 <error id="JVMTI_ERROR_INVALID_MODULE">
6653 If <paramlink id="to_module"></paramlink> is not a module object.
6654 </error>
6655 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
6656 If the package <paramlink id="pkg_name"></paramlink>
6657 does not belong to the module.
6658 </error>
6659 <error id="JVMTI_ERROR_UNMODIFIABLE_MODULE">
6660 if the module cannot be modified.
6661 See <functionlink id="IsModifiableModule"/>.
6662 </error>
6663 </errors>
6664 </function>
6665
6666 <function id="AddModuleOpens" num="96" since="9">
6667 <synopsis>Add Module Opens</synopsis>
6668 <description>
6669 Update a module to open a package to another module.
6670 This function is a no-op when <paramlink id="module"></paramlink>
6671 is an unnamed module or an open module.
6672 This function facilitates the instrumentation of code
6673 in modules where that instrumentation requires
6674 expanding the set of packages that a module opens to
6675 other modules.
6676 </description>
6677 <origin>new</origin>
6678 <capabilities>
6679 </capabilities>
6680 <parameters>
6681 <param id="module">
6682 <ptrtype><jobject/></ptrtype>
6683 <description>
6684 The module to update.
6685 </description>
6686 </param>
6687 <param id="pkg_name">
6688 <inbuf><char/></inbuf>
6689 <description>
6690 The package name of the package to open.
6691 </description>
6692 </param>
6693 <param id="to_module">
6694 <ptrtype><jobject/></ptrtype>
6695 <description>
6696 The module with the package to open.
6697 If the <code>to_module</code> is not a subclass of
6698 <code>java.lang.Module</code> this function returns
6699 <errorlink id="JVMTI_ERROR_INVALID_MODULE"></errorlink>.
6700 </description>
6701 </param>
6702 </parameters>
6703 <errors>
6704 <error id="JVMTI_ERROR_INVALID_MODULE">
6705 If <paramlink id="module"></paramlink> is not a module object.
6706 </error>
6707 <error id="JVMTI_ERROR_INVALID_MODULE">
6708 If <paramlink id="to_module"></paramlink> is not a module object.
6709 </error>
6710 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
6711 If the package <paramlink id="pkg_name"></paramlink>
6712 does not belong to the module.
6713 </error>
6714 <error id="JVMTI_ERROR_UNMODIFIABLE_MODULE">
6715 if the module cannot be modified.
6716 See <functionlink id="IsModifiableModule"/>.
6717 </error>
6718 </errors>
6719 </function>
6720
6721 <function id="AddModuleUses" num="97" since="9">
6722 <synopsis>Add Module Uses</synopsis>
6723 <description>
6724 Updates a module to add a service to the set of services that
6725 a module uses. This function is a no-op when the module
6726 is an unnamed module.
6727 This function facilitates the instrumentation of code
6728 in named modules where that instrumentation requires
6729 expanding the set of services that a module is using.
6730 </description>
6731 <origin>new</origin>
6732 <capabilities>
6733 </capabilities>
6734 <parameters>
6735 <param id="module">
6736 <ptrtype><jobject/></ptrtype>
6737 <description>
6738 The module to update.
6739 </description>
6740 </param>
6741 <param id="service">
6742 <ptrtype><jclass/></ptrtype>
6743 <description>
6744 The service to use.
6745 </description>
6746 </param>
6747 </parameters>
6748 <errors>
6749 <error id="JVMTI_ERROR_INVALID_MODULE">
6750 If <paramlink id="module"></paramlink> is not a module object.
6751 </error>
6752 <error id="JVMTI_ERROR_INVALID_CLASS">
6753 If <paramlink id="service"></paramlink> is not a class object.
6754 </error>
6755 <error id="JVMTI_ERROR_UNMODIFIABLE_MODULE">
6756 if the module cannot be modified.
6757 See <functionlink id="IsModifiableModule"/>.
6758 </error>
6759 </errors>
6760 </function>
6761
6762 <function id="AddModuleProvides" num="98" since="9">
6763 <synopsis>Add Module Provides</synopsis>
6764 <description>
6765 Updates a module to add a service to the set of services that
6766 a module provides. This function is a no-op when the module
6767 is an unnamed module.
6768 This function facilitates the instrumentation of code
6769 in named modules where that instrumentation requires
6770 changes to the services that are provided.
6771 </description>
6772 <origin>new</origin>
6773 <capabilities>
6774 </capabilities>
6775 <parameters>
6776 <param id="module">
6777 <ptrtype><jobject/></ptrtype>
6778 <description>
6779 The module to update.
6780 </description>
6781 </param>
6782 <param id="service">
6783 <ptrtype><jclass/></ptrtype>
6784 <description>
6785 The service to provide.
6786 </description>
6787 </param>
6788 <param id="impl_class">
6789 <ptrtype><jclass/></ptrtype>
6790 <description>
6791 The implementation class for the provided service.
6792 </description>
6793 </param>
6794 </parameters>
6795 <errors>
6796 <error id="JVMTI_ERROR_INVALID_MODULE">
6797 If <paramlink id="module"></paramlink> is not a module object.
6798 </error>
6799 <error id="JVMTI_ERROR_INVALID_CLASS">
6800 If <paramlink id="service"></paramlink> is not a class object.
6801 </error>
6802 <error id="JVMTI_ERROR_INVALID_CLASS">
6803 If <paramlink id="impl_class"></paramlink> is not a class object.
6804 </error>
6805 <error id="JVMTI_ERROR_UNMODIFIABLE_MODULE">
6806 if the module cannot be modified.
6807 See <functionlink id="IsModifiableModule"/>.
6808 </error>
6809 </errors>
6810 </function>
6811
6812 <function id="IsModifiableModule" num="99" since="9">
6813 <synopsis>Is Modifiable Module</synopsis>
6814 <description>
6815 Determines whether a module is modifiable.
6816 If a module is modifiable then this module can be updated with
6817 <functionlink id="AddModuleReads"/>, <functionlink id="AddModuleExports"/>,
6818 <functionlink id="AddModuleOpens"/>, <functionlink id="AddModuleUses"/>,
6819 and <functionlink id="AddModuleProvides"/>. If a module is not modifiable
6820 then the module can not be updated with these functions. The result of
6821 this function is always <code>JNI_TRUE</code> when called to determine
6822 if an unnamed module is modifiable.
6823 </description>
6824 <origin>new</origin>
6825 <capabilities>
6826 </capabilities>
6827 <parameters>
6828 <param id="module">
6829 <ptrtype><jobject/></ptrtype>
6830 <description>
6831 The module to query.
6832 </description>
6833 </param>
6834 <param id="is_modifiable_module_ptr">
6835 <outptr><jboolean/></outptr>
6836 <description>
6837 On return, points to the boolean result of this function.
6838 </description>
6839 </param>
6840 </parameters>
6841 <errors>
6842 <error id="JVMTI_ERROR_INVALID_MODULE">
6843 If <paramlink id="module"></paramlink> is not a module object.
6844 </error>
6845 </errors>
6846 </function>
6847
6848 </category>
6849
6850 <category id="class" label="Class">
6851
6852 <intro>
6853 </intro>
6854
6855 <function id="GetLoadedClasses" jkernel="yes" num="78">
6856 <synopsis>Get Loaded Classes</synopsis>
6857 <description>
6858 Return an array of all classes loaded in the virtual machine.
6859 The number of classes in the array is returned via
6860 <code>class_count_ptr</code>, and the array itself via
6861 <code>classes_ptr</code>.
6862 <p/>
6863 Array classes of all types (including arrays of primitive types) are
6864 included in the returned list. Primitive classes (for example,
6865 <code>java.lang.Integer.TYPE</code>) are <i>not</i> included in this list.
6866 </description>
6867 <origin>jvmdi</origin>
6868 <capabilities>
6869 </capabilities>
6870 <parameters>
6871 <param id="class_count_ptr">
6872 <outptr><jint/></outptr>
6873 <description>
6874 On return, points to the number of classes.
6875 </description>
6876 </param>
6877 <param id="classes_ptr">
6878 <allocbuf outcount="class_count_ptr"><jclass/></allocbuf>
6879 <description>
6880 On return, points to an array of references, one
6881 for each class.
6882 </description>
6883 </param>
6884 </parameters>
6885 <errors>
6886 </errors>
6887 </function>
6888
6889 <function id="GetClassLoaderClasses" jkernel="yes" num="79">
6890 <synopsis>Get Classloader Classes</synopsis>
6891 <description>
6892 Returns an array of those classes for which this class loader has
6893 been recorded as an initiating loader. Each
6894 class in the returned array was created by this class loader,
6895 either by defining it directly or by delegation to another class loader.
6896 See <vmspec chapter="5.3"/>.
6897 <p/>
6898 The number of classes in the array is returned via
6899 <code>class_count_ptr</code>, and the array itself via
6900 <code>classes_ptr</code>.
6901 </description>
6902 <origin>jvmdi</origin>
6903 <capabilities>
6904 </capabilities>
6905 <parameters>
6906 <param id="initiating_loader">
6907 <ptrtype>
6908 <jobject/>
6909 <nullok>the classes initiated by the bootstrap loader will be returned</nullok>
6910 </ptrtype>
6911 <description>
6912 An initiating class loader.
6913 </description>
6914 </param>
6915 <param id="class_count_ptr">
6916 <outptr><jint/></outptr>
6917 <description>
6918 On return, points to the number of classes.
6919 </description>
6920 </param>
6921 <param id="classes_ptr">
6922 <allocbuf outcount="class_count_ptr"><jclass/></allocbuf>
6923 <description>
6924 On return, points to an array of references, one
6925 for each class.
6926 </description>
6927 </param>
6928 </parameters>
6929 <errors>
6930 </errors>
6931 </function>
6932
6933 <function id="GetClassSignature" phase="start" num="48">
6934 <synopsis>Get Class Signature</synopsis>
6935 <description>
6936 For the class indicated by <code>klass</code>, return the
6937 <externallink id="jni/types.html#type-signatures">JNI
6938 type signature</externallink>
6939 and the generic signature of the class.
6940 For example, <code>java.util.List</code> is <code>"Ljava/util/List;"</code>
6941 and <code>int[]</code> is <code>"[I"</code>
6942 The returned name for primitive classes
6943 is the type signature character of the corresponding primitive type.
6944 For example, <code>java.lang.Integer.TYPE</code> is <code>"I"</code>.
6945 </description>
6946 <origin>jvmdiClone</origin>
6947 <capabilities>
6948 </capabilities>
6949 <parameters>
6950 <param id="klass">
6951 <jclass/>
6952 <description>
6953 The class to query.
6954 </description>
6955 </param>
6956 <param id="signature_ptr">
6957 <allocbuf>
6958 <char/>
6959 <nullok>the signature is not returned</nullok>
6960 </allocbuf>
6961 <description>
6962 On return, points to the JNI type signature of the class, encoded as a
6963 <internallink id="mUTF">modified UTF-8</internallink> string.
6964 </description>
6965 </param>
6966 <param id="generic_ptr">
6967 <allocbuf>
6968 <char/>
6969 <nullok>the generic signature is not returned</nullok>
6970 </allocbuf>
6971 <description>
6972 On return, points to the generic signature of the class, encoded as a
6973 <internallink id="mUTF">modified UTF-8</internallink> string.
6974 If there is no generic signature attribute for the class, then,
6975 on return, points to <code>NULL</code>.
6976 </description>
6977 </param>
6978 </parameters>
6979 <errors>
6980 </errors>
6981 </function>
6982
6983 <function id="GetClassStatus" phase="start" num="49">
6984 <synopsis>Get Class Status</synopsis>
6985 <description>
6986 Get the status of the class. Zero or more of the following bits can be
6987 set.
6988 <constants id="jvmtiClassStatus" label="Class Status Flags" kind="bits">
6989 <constant id="JVMTI_CLASS_STATUS_VERIFIED" num="1">
6990 Class bytecodes have been verified
6991 </constant>
6992 <constant id="JVMTI_CLASS_STATUS_PREPARED" num="2">
6993 Class preparation is complete
6994 </constant>
6995 <constant id="JVMTI_CLASS_STATUS_INITIALIZED" num="4">
6996 Class initialization is complete. Static initializer has been run.
6997 </constant>
6998 <constant id="JVMTI_CLASS_STATUS_ERROR" num="8">
6999 Error during initialization makes class unusable
7000 </constant>
7001 <constant id="JVMTI_CLASS_STATUS_ARRAY" num="16">
7002 Class is an array. If set, all other bits are zero.
7003 </constant>
7004 <constant id="JVMTI_CLASS_STATUS_PRIMITIVE" num="32">
7005 Class is a primitive class (for example, <code>java.lang.Integer.TYPE</code>).
7006 If set, all other bits are zero.
7007 </constant>
7008 </constants>
7009 </description>
7010 <origin>jvmdi</origin>
7011 <capabilities>
7012 </capabilities>
7013 <parameters>
7014 <param id="klass">
7015 <jclass/>
7016 <description>
7017 The class to query.
7018 </description>
7019 </param>
7020 <param id="status_ptr">
7021 <outptr><jint/></outptr>
7022 <description>
7023 On return, points to the current state of this class as one or
7024 more of the <internallink id="jvmtiClassStatus">class status flags</internallink>.
7025 </description>
7026 </param>
7027 </parameters>
7028 <errors>
7029 </errors>
7030 </function>
7031
7032 <function id="GetSourceFileName" phase="start" num="50">
7033 <synopsis>Get Source File Name</synopsis>
7034 <description>
7035 For the class indicated by <code>klass</code>, return the source file
7036 name via <code>source_name_ptr</code>. The returned string
7037 is a file name only and never contains a directory name.
7038 <p/>
7039 For primitive classes (for example, <code>java.lang.Integer.TYPE</code>)
7040 and for arrays this function returns
7041 <errorlink id="JVMTI_ERROR_ABSENT_INFORMATION"></errorlink>.
7042 </description>
7043 <origin>jvmdi</origin>
7044 <capabilities>
7045 <required id="can_get_source_file_name"></required>
7046 </capabilities>
7047 <parameters>
7048 <param id="klass">
7049 <jclass/>
7050 <description>
7051 The class to query.
7052 </description>
7053 </param>
7054 <param id="source_name_ptr">
7055 <allocbuf><char/></allocbuf>
7056 <description>
7057 On return, points to the class's source file name, encoded as a
7058 <internallink id="mUTF">modified UTF-8</internallink> string.
7059 </description>
7060 </param>
7061 </parameters>
7062 <errors>
7063 <error id="JVMTI_ERROR_ABSENT_INFORMATION">
7064 Class information does not include a source file name. This includes
7065 cases where the class is an array class or primitive class.
7066 </error>
7067 </errors>
7068 </function>
7069
7070 <function id="GetClassModifiers" phase="start" num="51">
7071 <synopsis>Get Class Modifiers</synopsis>
7072 <description>
7073 For the class indicated by <code>klass</code>, return the access
7074 flags
7075 via <code>modifiers_ptr</code>.
7076 Access flags are defined in <vmspec chapter="4"/>.
7077 <p/>
7078 If the class is an array class, then its public, private, and protected
7079 modifiers are the same as those of its component type. For arrays of
7080 primitives, this component type is represented by one of the primitive
7081 classes (for example, <code>java.lang.Integer.TYPE</code>).
7082 <p/>
7083 If the class is a primitive class, its public modifier is always true,
7084 and its protected and private modifiers are always false.
7085 <p/>
7086 If the class is an array class or a primitive class then its final
7087 modifier is always true and its interface modifier is always false.
7088 The values of its other modifiers are not determined by this specification.
7089
7090 </description>
7091 <origin>jvmdi</origin>
7092 <capabilities>
7093 </capabilities>
7094 <parameters>
7095 <param id="klass">
7096 <jclass/>
7097 <description>
7098 The class to query.
7099 </description>
7100 </param>
7101 <param id="modifiers_ptr">
7102 <outptr><jint/></outptr>
7103 <description>
7104 On return, points to the current access flags of this class.
7105
7106 </description>
7107 </param>
7108 </parameters>
7109 <errors>
7110 </errors>
7111 </function>
7112
7113 <function id="GetClassMethods" phase="start" num="52">
7114 <synopsis>Get Class Methods</synopsis>
7115 <description>
7116 For the class indicated by <code>klass</code>, return a count of
7117 methods via <code>method_count_ptr</code> and a list of
7118 method IDs via <code>methods_ptr</code>. The method list contains
7119 constructors and static initializers as well as true methods.
7120 Only directly declared methods are returned (not inherited methods).
7121 An empty method list is returned for array classes and primitive classes
7122 (for example, <code>java.lang.Integer.TYPE</code>).
7123 </description>
7124 <origin>jvmdi</origin>
7125 <capabilities>
7126 <capability id="can_maintain_original_method_order"/>
7127 </capabilities>
7128 <parameters>
7129 <param id="klass">
7130 <jclass/>
7131 <description>
7132 The class to query.
7133 </description>
7134 </param>
7135 <param id="method_count_ptr">
7136 <outptr><jint/></outptr>
7137 <description>
7138 On return, points to the number of methods declared in this class.
7139 </description>
7140 </param>
7141 <param id="methods_ptr">
7142 <allocbuf outcount="method_count_ptr"><jmethodID class="klass"/></allocbuf>
7143 <description>
7144 On return, points to the method ID array.
7145 </description>
7146 </param>
7147 </parameters>
7148 <errors>
7149 <error id="JVMTI_ERROR_CLASS_NOT_PREPARED">
7150 <paramlink id="klass"></paramlink> is not prepared.
7151 </error>
7152 </errors>
7153 </function>
7154
7155 <function id="GetClassFields" phase="start" num="53">
7156 <synopsis>Get Class Fields</synopsis>
7157 <description>
7158 For the class indicated by <code>klass</code>, return a count of fields
7159 via <code>field_count_ptr</code> and a list of field IDs via
7160 <code>fields_ptr</code>.
7161 Only directly declared fields are returned (not inherited fields).
7162 Fields are returned in the order they occur in the class file.
7163 An empty field list is returned for array classes and primitive classes
7164 (for example, <code>java.lang.Integer.TYPE</code>).
7165 Use JNI to determine the length of an array.
7166 </description>
7167 <origin>jvmdi</origin>
7168 <capabilities>
7169 </capabilities>
7170 <parameters>
7171 <param id="klass">
7172 <jclass/>
7173 <description>
7174 The class to query.
7175 </description>
7176 </param>
7177 <param id="field_count_ptr">
7178 <outptr><jint/></outptr>
7179 <description>
7180 On return, points to the number of fields declared in this class.
7181 </description>
7182 </param>
7183 <param id="fields_ptr">
7184 <allocbuf outcount="field_count_ptr"><jfieldID/></allocbuf>
7185 <description>
7186 On return, points to the field ID array.
7187 </description>
7188 </param>
7189 </parameters>
7190 <errors>
7191 <error id="JVMTI_ERROR_CLASS_NOT_PREPARED">
7192 <paramlink id="klass"></paramlink> is not prepared.
7193 </error>
7194 </errors>
7195 </function>
7196
7197 <function id="GetImplementedInterfaces" phase="start" num="54">
7198 <synopsis>Get Implemented Interfaces</synopsis>
7199 <description>
7200 Return the direct super-interfaces of this class. For a class, this
7201 function returns the interfaces declared in its <code>implements</code>
7202 clause. For an interface, this function returns the interfaces declared in
7203 its <code>extends</code> clause.
7204 An empty interface list is returned for array classes and primitive classes
7205 (for example, <code>java.lang.Integer.TYPE</code>).
7206 </description>
7207 <origin>jvmdi</origin>
7208 <capabilities>
7209 </capabilities>
7210 <parameters>
7211 <param id="klass">
7212 <jclass/>
7213 <description>
7214 The class to query.
7215 </description>
7216 </param>
7217 <param id="interface_count_ptr">
7218 <outptr><jint/></outptr>
7219 <description>
7220 On return, points to the number of interfaces.
7221 </description>
7222 </param>
7223 <param id="interfaces_ptr">
7224 <allocbuf outcount="interface_count_ptr"><jclass/></allocbuf>
7225 <description>
7226 On return, points to the interface array.
7227 </description>
7228 </param>
7229 </parameters>
7230 <errors>
7231 <error id="JVMTI_ERROR_CLASS_NOT_PREPARED">
7232 <paramlink id="klass"></paramlink> is not prepared.
7233 </error>
7234 </errors>
7235 </function>
7236
7237 <function id="GetClassVersionNumbers" phase="start" num="145" since="1.1">
7238 <synopsis>Get Class Version Numbers</synopsis>
7239 <description>
7240 For the class indicated by <code>klass</code>,
7241 return the minor and major version numbers,
7242 as defined in
7243 <vmspec chapter="4"/>.
7244 </description>
7245 <origin>new</origin>
7246 <capabilities>
7247 </capabilities>
7248 <parameters>
7249 <param id="klass">
7250 <jclass/>
7251 <description>
7252 The class to query.
7253 </description>
7254 </param>
7255 <param id="minor_version_ptr">
7256 <outptr><jint/></outptr>
7257 <description>
7258 On return, points to the value of the
7259 <code>minor_version</code> item of the
7260 Class File Format.
7261 Note: to be consistent with the Class File Format,
7262 the minor version number is the first parameter.
7263 </description>
7264 </param>
7265 <param id="major_version_ptr">
7266 <outptr><jint/></outptr>
7267 <description>
7268 On return, points to the value of the
7269 <code>major_version</code> item of the
7270 Class File Format.
7271 </description>
7272 </param>
7273 </parameters>
7274 <errors>
7275 <error id="JVMTI_ERROR_ABSENT_INFORMATION">
7276 The class is a primitive or array class.
7277 </error>
7278 </errors>
7279 </function>
7280
7281 <function id="GetConstantPool" phase="start" num="146" since="1.1">
7282 <synopsis>Get Constant Pool</synopsis>
7283 <description>
7284 For the class indicated by <code>klass</code>,
7285 return the raw bytes of the constant pool in the format of the
7286 <code>constant_pool</code> item of
7287 <vmspec chapter="4"/>.
7288 The format of the constant pool may differ between versions
7289 of the Class File Format, so, the
7290 <functionlink id="GetClassVersionNumbers">minor and major
7291 class version numbers</functionlink> should be checked for
7292 compatibility.
7293 <p/>
7294 The returned constant pool might not have the same layout or
7295 contents as the constant pool in the defining class file.
7296 The constant pool returned by GetConstantPool() may have
7297 more or fewer entries than the defining constant pool.
7298 Entries may be in a different order.
7299 The constant pool returned by GetConstantPool() will match the
7300 constant pool used by
7301 <functionlink id="GetBytecodes">GetBytecodes()</functionlink>.
7302 That is, the bytecodes returned by GetBytecodes() will have
7303 constant pool indices which refer to constant pool entries returned
7304 by GetConstantPool().
7305 Note that since <functionlink id="RetransformClasses"/>
7306 and <functionlink id="RedefineClasses"/> can change
7307 the constant pool, the constant pool returned by this function
7308 can change accordingly. Thus, the correspondence between
7309 GetConstantPool() and GetBytecodes() does not hold if there
7310 is an intervening class retransformation or redefinition.
7311 The value of a constant pool entry used by a given bytecode will
7312 match that of the defining class file (even if the indices don't match).
7313 Constant pool entries which are not used directly or indirectly by
7314 bytecodes (for example, UTF-8 strings associated with annotations) are
7315 not required to exist in the returned constant pool.
7316 </description>
7317 <origin>new</origin>
7318 <capabilities>
7319 <required id="can_get_constant_pool"></required>
7320 </capabilities>
7321 <parameters>
7322 <param id="klass">
7323 <jclass/>
7324 <description>
7325 The class to query.
7326 </description>
7327 </param>
7328 <param id="constant_pool_count_ptr">
7329 <outptr><jint/></outptr>
7330 <description>
7331 On return, points to the number of entries
7332 in the constant pool table plus one.
7333 This corresponds to the <code>constant_pool_count</code>
7334 item of the Class File Format.
7335 </description>
7336 </param>
7337 <param id="constant_pool_byte_count_ptr">
7338 <outptr><jint/></outptr>
7339 <description>
7340 On return, points to the number of bytes
7341 in the returned raw constant pool.
7342 </description>
7343 </param>
7344 <param id="constant_pool_bytes_ptr">
7345 <allocbuf outcount="constant_pool_byte_count_ptr"><uchar/></allocbuf>
7346 <description>
7347 On return, points to the raw constant pool, that is the bytes
7348 defined by the <code>constant_pool</code> item of the
7349 Class File Format
7350 </description>
7351 </param>
7352 </parameters>
7353 <errors>
7354 <error id="JVMTI_ERROR_ABSENT_INFORMATION">
7355 The class is a primitive or array class.
7356 </error>
7357 </errors>
7358 </function>
7359
7360 <function id="IsInterface" phase="start" num="55">
7361 <synopsis>Is Interface</synopsis>
7362 <description>
7363 Determines whether a class object reference represents an interface.
7364 The <code>jboolean</code> result is
7365 <code>JNI_TRUE</code> if the "class" is actually an interface,
7366 <code>JNI_FALSE</code> otherwise.
7367 </description>
7368 <origin>jvmdi</origin>
7369 <capabilities>
7370 </capabilities>
7371 <parameters>
7372 <param id="klass">
7373 <jclass/>
7374 <description>
7375 The class to query.
7376 </description>
7377 </param>
7378 <param id="is_interface_ptr">
7379 <outptr><jboolean/></outptr>
7380 <description>
7381 On return, points to the boolean result of this function.
7382
7383 </description>
7384 </param>
7385 </parameters>
7386 <errors>
7387 </errors>
7388 </function>
7389
7390 <function id="IsArrayClass" phase="start" num="56">
7391 <synopsis>Is Array Class</synopsis>
7392 <description>
7393 Determines whether a class object reference represents an array.
7394 The <code>jboolean</code> result is
7395 <code>JNI_TRUE</code> if the class is an array,
7396 <code>JNI_FALSE</code> otherwise.
7397 </description>
7398 <origin>jvmdi</origin>
7399 <capabilities>
7400 </capabilities>
7401 <parameters>
7402 <param id="klass">
7403 <jclass/>
7404 <description>
7405 The class to query.
7406 </description>
7407 </param>
7408 <param id="is_array_class_ptr">
7409 <outptr><jboolean/></outptr>
7410 <description>
7411 On return, points to the boolean result of this function.
7412
7413 </description>
7414 </param>
7415 </parameters>
7416 <errors>
7417 </errors>
7418 </function>
7419
7420 <function id="IsModifiableClass" jkernel="yes" phase="start" num="45" since="1.1">
7421 <synopsis>Is Modifiable Class</synopsis>
7422 <description>
7423 Determines whether a class is modifiable.
7424 If a class is modifiable (<paramlink id="is_modifiable_class_ptr"/>
7425 returns <code>JNI_TRUE</code>) the class can be
7426 redefined with <functionlink id="RedefineClasses"/> (assuming
7427 the agent possesses the
7428 <fieldlink id="can_redefine_classes" struct="jvmtiCapabilities"/>
7429 capability) or
7430 retransformed with <functionlink id="RetransformClasses"/> (assuming
7431 the agent possesses the
7432 <fieldlink id="can_retransform_classes" struct="jvmtiCapabilities"/>
7433 capability).
7434 If a class is not modifiable (<paramlink id="is_modifiable_class_ptr"/>
7435 returns <code>JNI_FALSE</code>) the class can be neither
7436 redefined nor retransformed.
7437 <p/>
7438 Primitive classes (for example, <code>java.lang.Integer.TYPE</code>),
7439 array classes, and some implementation defined classes are never modifiable.
7440 <p/>
7441 </description>
7442 <origin>new</origin>
7443 <capabilities>
7444 <capability id="can_redefine_any_class">
7445 If possessed then all classes (except primitive, array, and some implementation defined
7446 classes) are modifiable (redefine or retransform).
7447 </capability>
7448 <capability id="can_retransform_any_class">
7449 If possessed then all classes (except primitive, array, and some implementation defined
7450 classes) are modifiable with <functionlink id="RetransformClasses"/>.
7451 </capability>
7452 <capability id="can_redefine_classes">
7453 No effect on the result of the function.
7454 But must additionally be possessed to modify the class with
7455 <functionlink id="RedefineClasses"/>.
7456 </capability>
7457 <capability id="can_retransform_classes">
7458 No effect on the result of the function.
7459 But must additionally be possessed to modify the class with
7460 <functionlink id="RetransformClasses"/>.
7461 </capability>
7462 </capabilities>
7463 <parameters>
7464 <param id="klass">
7465 <jclass/>
7466 <description>
7467 The class to query.
7468 </description>
7469 </param>
7470 <param id="is_modifiable_class_ptr">
7471 <outptr><jboolean/></outptr>
7472 <description>
7473 On return, points to the boolean result of this function.
7474 </description>
7475 </param>
7476 </parameters>
7477 <errors>
7478 </errors>
7479 </function>
7480
7481 <function id="GetClassLoader" phase="start" num="57">
7482 <synopsis>Get Class Loader</synopsis>
7483 <description>
7484 For the class indicated by <code>klass</code>, return via
7485 <code>classloader_ptr</code> a reference to the class loader for the
7486 class.
7487 </description>
7488 <origin>jvmdi</origin>
7489 <capabilities>
7490 </capabilities>
7491 <parameters>
7492 <param id="klass">
7493 <jclass/>
7494 <description>
7495 The class to query.
7496 </description>
7497 </param>
7498 <param id="classloader_ptr">
7499 <outptr><jobject/></outptr>
7500 <description>
7501 On return, points to the class loader that loaded
7502 this class.
7503 If the class was not created by a class loader
7504 or if the class loader is the bootstrap class loader,
7505 points to <code>NULL</code>.
7506 </description>
7507 </param>
7508 </parameters>
7509 <errors>
7510 </errors>
7511
7512 </function>
7513
7514 <function id="GetSourceDebugExtension" phase="start" num="90">
7515 <synopsis>Get Source Debug Extension</synopsis>
7516 <description>
7517 For the class indicated by <code>klass</code>, return the debug
7518 extension via <code>source_debug_extension_ptr</code>.
7519 The returned string
7520 contains exactly the debug extension information present in the
7521 class file of <code>klass</code>.
7522 </description>
7523 <origin>jvmdi</origin>
7524 <capabilities>
7525 <required id="can_get_source_debug_extension"></required>
7526 </capabilities>
7527 <parameters>
7528 <param id="klass">
7529 <jclass/>
7530 <description>
7531 The class to query.
7532 </description>
7533 </param>
7534 <param id="source_debug_extension_ptr">
7535 <allocbuf><char/></allocbuf>
7536 <description>
7537 On return, points to the class's debug extension, encoded as a
7538 <internallink id="mUTF">modified UTF-8</internallink> string.
7539 </description>
7540 </param>
7541 </parameters>
7542 <errors>
7543 <error id="JVMTI_ERROR_ABSENT_INFORMATION">
7544 Class information does not include a debug extension.
7545 </error>
7546 </errors>
7547 </function>
7548
7549 <function id="RetransformClasses" jkernel="yes" num="152" since="1.1">
7550 <synopsis>Retransform Classes</synopsis>
7551 <description>
7552 This function facilitates the
7553 <internallink id="bci">bytecode instrumentation</internallink>
7554 of already loaded classes.
7555 To replace the class definition without reference to the existing
7556 bytecodes, as one might do when recompiling from source for
7557 fix-and-continue debugging, <functionlink id="RedefineClasses"/>
7558 function should be used instead.
7559 <p/>
7560 When classes are initially loaded or when they are
7561 <functionlink id="RedefineClasses">redefined</functionlink>,
7562 the initial class file bytes can be transformed with the
7563 <eventlink id="ClassFileLoadHook"/> event.
7564 This function reruns the transformation process
7565 (whether or not a transformation has previously occurred).
7566 This retransformation follows these steps:
7567 <ul>
7568 <li>starting from the initial class file bytes
7569 </li>
7570 <li>for each <fieldlink id="can_retransform_classes"
7571 struct="jvmtiCapabilities">retransformation
7572 incapable</fieldlink>
7573 agent which received a
7574 <code>ClassFileLoadHook</code> event during the previous
7575 load or redefine, the bytes it returned
7576 (via the <code>new_class_data</code> parameter)
7577 are reused as the output of the transformation;
7578 note that this is equivalent to reapplying
7579 the previous transformation, unaltered. except that
7580 the <code>ClassFileLoadHook</code> event
7581 is <b>not</b> sent to these agents
7582 </li>
7583 <li>for each <fieldlink id="can_retransform_classes"
7584 struct="jvmtiCapabilities">retransformation
7585 capable</fieldlink>
7586 agent, the <code>ClassFileLoadHook</code> event is sent,
7587 allowing a new transformation to be applied
7588 </li>
7589 <li>the transformed class file bytes are installed as the new
7590 definition of the class
7591 </li>
7592 </ul>
7593 See the <eventlink id="ClassFileLoadHook"/> event for more details.
7594 <p/>
7595 The initial class file bytes represent the bytes passed to
7596 <code>ClassLoader.defineClass</code>
7597 or <code>RedefineClasses</code> (before any transformations
7598 were applied), however they may not exactly match them.
7599 The constant pool may differ in ways described in
7600 <functionlink id="GetConstantPool"/>.
7601 Constant pool indices in the bytecodes of methods will correspond.
7602 Some attributes may not be present.
7603 Where order is not meaningful, for example the order of methods,
7604 order may not be preserved.
7605 <p/>
7606 Retransformation can cause new versions of methods to be installed.
7607 Old method versions may become
7608 <internallink id="obsoleteMethods">obsolete</internallink>
7609 The new method version will be used on new invokes.
7610 If a method has active stack frames, those active frames continue to
7611 run the bytecodes of the original method version.
7612 <p/>
7613 This function does not cause any initialization except that which
7614 would occur under the customary JVM semantics.
7615 In other words, retransforming a class does not cause its initializers to be
7616 run. The values of static fields will remain as they were
7617 prior to the call.
7618 <p/>
7619 Threads need not be suspended.
7620 <p/>
7621 All breakpoints in the class are cleared.
7622 <p/>
7623 All attributes are updated.
7624 <p/>
7625 Instances of the retransformed class are not affected -- fields retain their
7626 previous values.
7627 <functionlink id="GetTag">Tags</functionlink> on the instances are
7628 also unaffected.
7629 <p/>
7630 In response to this call, no events other than the
7631 <eventlink id="ClassFileLoadHook"/> event
7632 will be sent.
7633 <p/>
7634 The retransformation may change method bodies, the constant pool and attributes
7635 (unless explicitly prohibited).
7636 The retransformation must not add, remove or rename fields or methods, change the
7637 signatures of methods, change modifiers, or change inheritance.
7638 The retransformation must not change the <code>NestHost</code> or
7639 <code>NestMembers</code> attributes.
7640 These restrictions may be lifted in future versions.
7641 See the error return description below for information on error codes
7642 returned if an unsupported retransformation is attempted.
7643 The class file bytes are not verified or installed until they have passed
7644 through the chain of <eventlink id="ClassFileLoadHook"/> events, thus the
7645 returned error code reflects the result of the transformations.
7646 If any error code is returned other than <code>JVMTI_ERROR_NONE</code>,
7647 none of the classes to be retransformed will have a new definition installed.
7648 When this function returns (with the error code of <code>JVMTI_ERROR_NONE</code>)
7649 all of the classes to be retransformed will have their new definitions installed.
7650 </description>
7651 <origin>new</origin>
7652 <capabilities>
7653 <required id="can_retransform_classes"></required>
7654 <capability id="can_retransform_any_class"></capability>
7655 </capabilities>
7656 <parameters>
7657 <param id="class_count">
7658 <jint min="0"/>
7659 <description>
7660 The number of classes to be retransformed.
7661 </description>
7662 </param>
7663 <param id="classes">
7664 <inbuf incount="class_count"><jclass/></inbuf>
7665 <description>
7666 The array of classes to be retransformed.
7667 </description>
7668 </param>
7669 </parameters>
7670 <errors>
7671 <error id="JVMTI_ERROR_UNMODIFIABLE_CLASS">
7672 One of the <paramlink id="classes"/> cannot be modified.
7673 See <functionlink id="IsModifiableClass"/>.
7674 </error>
7675 <error id="JVMTI_ERROR_INVALID_CLASS">
7676 One of the <paramlink id="classes"/> is not a valid class.
7677 </error>
7678 <error id="JVMTI_ERROR_UNSUPPORTED_VERSION">
7679 A retransformed class file has a version number not supported by this VM.
7680 </error>
7681 <error id="JVMTI_ERROR_INVALID_CLASS_FORMAT">
7682 A retransformed class file is malformed (The VM would return a <code>ClassFormatError</code>).
7683 </error>
7684 <error id="JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION">
7685 The retransformed class file definitions would lead to a circular definition
7686 (the VM would return a <code>ClassCircularityError</code>).
7687 </error>
7688 <error id="JVMTI_ERROR_FAILS_VERIFICATION">
7689 The retransformed class file bytes fail verification.
7690 </error>
7691 <error id="JVMTI_ERROR_NAMES_DONT_MATCH">
7692 The class name defined in a retransformed class file is
7693 different from the name in the old class object.
7694 </error>
7695 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED">
7696 A retransformed class file would require adding a method.
7697 </error>
7698 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED">
7699 A retransformed class file changes a field.
7700 </error>
7701 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED">
7702 A direct superclass is different for a retransformed class file,
7703 or the set of directly implemented
7704 interfaces is different.
7705 </error>
7706 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED">
7707 A retransformed class file does not declare a method
7708 declared in the old class version.
7709 </error>
7710 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED">
7711 A retransformed class file has unsupported differences in class attributes.
7712 </error>
7713 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED">
7714 A retransformed class file has different class modifiers.
7715 </error>
7716 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED">
7717 A method in the retransformed class file has different modifiers
7718 than its counterpart in the old class version.
7719 </error>
7720 </errors>
7721 </function>
7722
7723 <function id="RedefineClasses" jkernel="yes" num="87">
7724 <synopsis>Redefine Classes</synopsis>
7725 <typedef id="jvmtiClassDefinition" label="Class redefinition description">
7726 <field id="klass">
7727 <jclass/>
7728 <description>
7729 Class object for this class
7730 </description>
7731 </field>
7732 <field id="class_byte_count">
7733 <jint/>
7734 <description>
7735 Number of bytes defining class (below)
7736 </description>
7737 </field>
7738 <field id="class_bytes">
7739 <inbuf incount="class_byte_count"><uchar/></inbuf>
7740 <description>
7741 Bytes defining class (in <vmspec chapter="4"/>)
7742 </description>
7743 </field>
7744 </typedef>
7745 <description>
7746 All classes given are redefined according to the definitions
7747 supplied.
7748 This function is used to replace the definition of a class
7749 with a new definition, as might be needed in fix-and-continue
7750 debugging.
7751 Where the existing class file bytes are to be transformed, for
7752 example in
7753 <internallink id="bci">bytecode instrumentation</internallink>,
7754 <functionlink id="RetransformClasses"/> should be used.
7755 <p/>
7756 Redefinition can cause new versions of methods to be installed.
7757 Old method versions may become
7758 <internallink id="obsoleteMethods">obsolete</internallink>
7759 The new method version will be used on new invokes.
7760 If a method has active stack frames, those active frames continue to
7761 run the bytecodes of the original method version.
7762 If resetting of stack frames is desired, use
7763 <functionlink id="PopFrame"></functionlink>
7764 to pop frames with obsolete method versions.
7765 <p/>
7766 This function does not cause any initialization except that which
7767 would occur under the customary JVM semantics.
7768 In other words, redefining a class does not cause its initializers to be
7769 run. The values of static fields will remain as they were
7770 prior to the call.
7771 <p/>
7772 Threads need not be suspended.
7773 <p/>
7774 All breakpoints in the class are cleared.
7775 <p/>
7776 All attributes are updated.
7777 <p/>
7778 Instances of the redefined class are not affected -- fields retain their
7779 previous values.
7780 <functionlink id="GetTag">Tags</functionlink> on the instances are
7781 also unaffected.
7782 <p/>
7783 In response to this call, the <jvmti/> event
7784 <eventlink id="ClassFileLoadHook">Class File Load Hook</eventlink>
7785 will be sent (if enabled), but no other <jvmti/> events will be sent.
7786 <p/>
7787 The redefinition may change method bodies, the constant pool and attributes
7788 (unless explicitly prohibited).
7789 The redefinition must not add, remove or rename fields or methods, change the
7790 signatures of methods, change modifiers, or change inheritance.
7791 The retransformation must not change the <code>NestHost</code> or
7792 <code>NestMembers</code> attributes.
7793 These restrictions may be lifted in future versions.
7794 See the error return description below for information on error codes
7795 returned if an unsupported redefinition is attempted.
7796 The class file bytes are not verified or installed until they have passed
7797 through the chain of <eventlink id="ClassFileLoadHook"/> events, thus the
7798 returned error code reflects the result of the transformations applied
7799 to the bytes passed into <paramlink id="class_definitions"/>.
7800 If any error code is returned other than <code>JVMTI_ERROR_NONE</code>,
7801 none of the classes to be redefined will have a new definition installed.
7802 When this function returns (with the error code of <code>JVMTI_ERROR_NONE</code>)
7803 all of the classes to be redefined will have their new definitions installed.
7804 </description>
7805 <origin>jvmdi</origin>
7806 <capabilities>
7807 <required id="can_redefine_classes"></required>
7808 <capability id="can_redefine_any_class"></capability>
7809 </capabilities>
7810 <parameters>
7811 <param id="class_count">
7812 <jint min="0"/>
7813 <description>
7814 The number of classes specified in <code>class_definitions</code>
7815 </description>
7816 </param>
7817 <param id="class_definitions">
7818 <inbuf incount="class_count"><struct>jvmtiClassDefinition</struct></inbuf>
7819 <description>
7820 The array of new class definitions
7821 </description>
7822 </param>
7823 </parameters>
7824 <errors>
7825 <error id="JVMTI_ERROR_NULL_POINTER">
7826 One of <code>class_bytes</code> is <code>NULL</code>.
7827 </error>
7828 <error id="JVMTI_ERROR_UNMODIFIABLE_CLASS">
7829 An element of <code>class_definitions</code> cannot be modified.
7830 See <functionlink id="IsModifiableClass"/>.
7831 </error>
7832 <error id="JVMTI_ERROR_INVALID_CLASS">
7833 An element of <code>class_definitions</code> is not a valid class.
7834 </error>
7835 <error id="JVMTI_ERROR_UNSUPPORTED_VERSION">
7836 A new class file has a version number not supported by this VM.
7837 </error>
7838 <error id="JVMTI_ERROR_INVALID_CLASS_FORMAT">
7839 A new class file is malformed (The VM would return a <code>ClassFormatError</code>).
7840 </error>
7841 <error id="JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION">
7842 The new class file definitions would lead to a circular definition
7843 (the VM would return a <code>ClassCircularityError</code>).
7844 </error>
7845 <error id="JVMTI_ERROR_FAILS_VERIFICATION">
7846 The class bytes fail verification.
7847 </error>
7848 <error id="JVMTI_ERROR_NAMES_DONT_MATCH">
7849 The class name defined in a new class file is
7850 different from the name in the old class object.
7851 </error>
7852 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED">
7853 A new class file would require adding a method.
7854 </error>
7855 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED">
7856 A new class version changes a field.
7857 </error>
7858 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED">
7859 A direct superclass is different for a new class
7860 version, or the set of directly implemented
7861 interfaces is different.
7862 </error>
7863 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED">
7864 A new class version does not declare a method
7865 declared in the old class version.
7866 </error>
7867 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED">
7868 A new class version has unsupported differences in class attributes.
7869 </error>
7870 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED">
7871 A new class version has different modifiers.
7872 </error>
7873 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED">
7874 A method in the new class version has different modifiers
7875 than its counterpart in the old class version.
7876 </error>
7877 <error id="JVMTI_ERROR_UNMODIFIABLE_MODULE">
7878 A module cannot be modified.
7879 See <functionlink id="IsModifiableModule"/>.
7880 </error>
7881 </errors>
7882 </function>
7883
7884 </category>
7885
7886 <category id="object" label="Object">
7887
7888 <function id="GetObjectSize" jkernel="yes" phase="start" num="154">
7889 <synopsis>Get Object Size</synopsis>
7890 <description>
7891 For the object indicated by <code>object</code>,
7892 return via <code>size_ptr</code> the size of the object.
7893 This size is an implementation-specific approximation of
7894 the amount of storage consumed by this object.
7895 It may include some or all of the object's overhead, and thus
7896 is useful for comparison within an implementation but not
7897 between implementations.
7898 The estimate may change during a single invocation of the JVM.
7899 </description>
7900 <origin>new</origin>
7901 <capabilities>
7902 </capabilities>
7903 <parameters>
7904 <param id="object">
7905 <jobject/>
7906 <description>
7907 The object to query.
7908 </description>
7909 </param>
7910 <param id="size_ptr">
7911 <outptr><jlong/></outptr>
7912 <description>
7913 On return, points to the object's size in bytes.
7914 </description>
7915 </param>
7916 </parameters>
7917 <errors>
7918 </errors>
7919 </function>
7920
7921 <function id="GetObjectHashCode" phase="start" num="58">
7922 <synopsis>Get Object Hash Code</synopsis>
7923 <description>
7924 For the object indicated by <code>object</code>,
7925 return via <code>hash_code_ptr</code> a hash code.
7926 This hash code could be used to maintain a hash table of object references,
7927 however, on some implementations this can cause significant performance
7928 impacts--in most cases
7929 <internallink id="Heap">tags</internallink>
7930 will be a more efficient means of associating information with objects.
7931 This function guarantees
7932 the same hash code value for a particular object throughout its life
7933 </description>
7934 <origin>jvmdi</origin>
7935 <capabilities>
7936 </capabilities>
7937 <parameters>
7938 <param id="object">
7939 <jobject/>
7940 <description>
7941 The object to query.
7942 </description>
7943 </param>
7944 <param id="hash_code_ptr">
7945 <outptr><jint/></outptr>
7946 <description>
7947 On return, points to the object's hash code.
7948 </description>
7949 </param>
7950 </parameters>
7951 <errors>
7952 </errors>
7953 </function>
7954
7955 <function id="GetObjectMonitorUsage" num="59">
7956 <synopsis>Get Object Monitor Usage</synopsis>
7957 <typedef id="jvmtiMonitorUsage" label="Object monitor usage information">
7958 <field id="owner">
7959 <jthread/>
7960 <description>
7961 The thread owning this monitor, or <code>NULL</code> if unused
7962 </description>
7963 </field>
7964 <field id="entry_count">
7965 <jint/>
7966 <description>
7967 The number of times the owning thread has entered the monitor
7968 </description>
7969 </field>
7970 <field id="waiter_count">
7971 <jint/>
7972 <description>
7973 The number of threads waiting to own this monitor
7974 </description>
7975 </field>
7976 <field id="waiters">
7977 <allocfieldbuf><jthread/></allocfieldbuf>
7978 <description>
7979 The <code>waiter_count</code> waiting threads
7980 </description>
7981 </field>
7982 <field id="notify_waiter_count">
7983 <jint/>
7984 <description>
7985 The number of threads waiting to be notified by this monitor
7986 </description>
7987 </field>
7988 <field id="notify_waiters">
7989 <allocfieldbuf><jthread/></allocfieldbuf>
7990 <description>
7991 The <code>notify_waiter_count</code> threads waiting to be notified
7992 </description>
7993 </field>
7994 </typedef>
7995 <description>
7996 Get information about the object's monitor.
7997 The fields of the <functionlink id="jvmtiMonitorUsage"></functionlink> structure
7998 are filled in with information about usage of the monitor.
7999 <todo>
8000 Decide and then clarify suspend requirements.
8001 </todo>
8002 </description>
8003 <origin>jvmdi</origin>
8004 <capabilities>
8005 <required id="can_get_monitor_info"></required>
8006 </capabilities>
8007 <parameters>
8008 <param id="object">
8009 <jobject/>
8010 <description>
8011 The object to query.
8012 </description>
8013 </param>
8014 <param id="info_ptr">
8015 <outptr><struct>jvmtiMonitorUsage</struct></outptr>
8016 <description>
8017 On return, filled with monitor information for the
8018 specified object.
8019 </description>
8020 </param>
8021 </parameters>
8022 <errors>
8023 </errors>
8024 </function>
8025
8026 <elide>
8027 <function id="GetObjectMonitors" num="116">
8028 <synopsis>Get Object Monitors</synopsis>
8029 <description>
8030 Return the list of object monitors.
8031 <p/>
8032 Note: details about each monitor can be examined with
8033 <functionlink id="GetObjectMonitorUsage"></functionlink>.
8034 </description>
8035 <origin>new</origin>
8036 <capabilities>
8037 <required id="can_get_monitor_info"></required>
8038 </capabilities>
8039 <parameters>
8040 <param id="monitorCnt">
8041 <outptr><jint/></outptr>
8042 <description>
8043 On return, pointer to the number
8044 of monitors returned in <code>monitors_ptr</code>.
8045 </description>
8046 </param>
8047 <param id="monitors_ptr">
8048 <allocbuf outcount="monitorCnt"><jobject/></allocbuf>
8049 <description>
8050 On return, pointer to the monitor list.
8051 </description>
8052 </param>
8053 </parameters>
8054 <errors>
8055 </errors>
8056 </function>
8057 </elide>
8058
8059 </category>
8060
8061 <category id="fieldCategory" label="Field">
8062
8063 <intro>
8064 </intro>
8065
8066 <function id="GetFieldName" phase="start" num="60">
8067 <synopsis>Get Field Name (and Signature)</synopsis>
8068 <description>
8069 For the field indicated by <paramlink id="klass"/> and <paramlink id="field"/>,
8070 return the field name via <paramlink id="name_ptr"/> and field signature via
8071 <paramlink id="signature_ptr"/>.
8072 <p/>
8073 Field signatures are defined in the
8074 <externallink id="jni/index.html">JNI Specification</externallink>
8075 and are referred to as <code>field descriptors</code> in
8076 <vmspec chapter="4.3.2"/>.
8077 </description>
8078 <origin>jvmdiClone</origin>
8079 <capabilities>
8080 </capabilities>
8081 <parameters>
8082 <param id="klass">
8083 <jclass field="field"/>
8084 <description>
8085 The class of the field to query.
8086 </description>
8087 </param>
8088 <param id="field">
8089 <jfieldID class="klass"/>
8090 <description>
8091 The field to query.
8092 </description>
8093 </param>
8094 <param id="name_ptr">
8095 <allocbuf>
8096 <char/>
8097 <nullok>the name is not returned</nullok>
8098 </allocbuf>
8099 <description>
8100 On return, points to the field name, encoded as a
8101 <internallink id="mUTF">modified UTF-8</internallink> string.
8102 </description>
8103 </param>
8104 <param id="signature_ptr">
8105 <allocbuf>
8106 <char/>
8107 <nullok>the signature is not returned</nullok>
8108 </allocbuf>
8109 <description>
8110 On return, points to the field signature, encoded as a
8111 <internallink id="mUTF">modified UTF-8</internallink> string.
8112 </description>
8113 </param>
8114 <param id="generic_ptr">
8115 <allocbuf>
8116 <char/>
8117 <nullok>the generic signature is not returned</nullok>
8118 </allocbuf>
8119 <description>
8120 On return, points to the generic signature of the field, encoded as a
8121 <internallink id="mUTF">modified UTF-8</internallink> string.
8122 If there is no generic signature attribute for the field, then,
8123 on return, points to <code>NULL</code>.
8124 </description>
8125 </param>
8126 </parameters>
8127 <errors>
8128 </errors>
8129 </function>
8130
8131 <function id="GetFieldDeclaringClass" phase="start" num="61">
8132 <synopsis>Get Field Declaring Class</synopsis>
8133 <description>
8134 For the field indicated by <code>klass</code> and <code>field</code>
8135 return the class that defined it via <code>declaring_class_ptr</code>.
8136 The declaring class will either be <code>klass</code>, a superclass, or
8137 an implemented interface.
8138 </description>
8139 <origin>jvmdi</origin>
8140 <capabilities>
8141 </capabilities>
8142 <parameters>
8143 <param id="klass">
8144 <jclass field="field"/>
8145 <description>
8146 The class to query.
8147 </description>
8148 </param>
8149 <param id="field">
8150 <jfieldID class="klass"/>
8151 <description>
8152 The field to query.
8153 </description>
8154 </param>
8155 <param id="declaring_class_ptr">
8156 <outptr><jclass/></outptr>
8157 <description>
8158 On return, points to the declaring class
8159 </description>
8160 </param>
8161 </parameters>
8162 <errors>
8163 </errors>
8164 </function>
8165
8166 <function id="GetFieldModifiers" phase="start" num="62">
8167 <synopsis>Get Field Modifiers</synopsis>
8168 <description>
8169 For the field indicated by <code>klass</code> and <code>field</code>
8170 return the access flags via <code>modifiers_ptr</code>.
8171 Access flags are defined in <vmspec chapter="4"/>.
8172 </description>
8173 <origin>jvmdi</origin>
8174 <capabilities>
8175 </capabilities>
8176 <parameters>
8177 <param id="klass">
8178 <jclass field="field"/>
8179 <description>
8180 The class to query.
8181 </description>
8182 </param>
8183 <param id="field">
8184 <jfieldID class="klass"/>
8185 <description>
8186 The field to query.
8187 </description>
8188 </param>
8189 <param id="modifiers_ptr">
8190 <outptr><jint/></outptr>
8191 <description>
8192 On return, points to the access flags.
8193 </description>
8194 </param>
8195 </parameters>
8196 <errors>
8197 </errors>
8198 </function>
8199
8200 <function id="IsFieldSynthetic" phase="start" num="63">
8201 <synopsis>Is Field Synthetic</synopsis>
8202 <description>
8203 For the field indicated by <code>klass</code> and <code>field</code>, return a
8204 value indicating whether the field is synthetic via <code>is_synthetic_ptr</code>.
8205 Synthetic fields are generated by the compiler but not present in the
8206 original source code.
8207 </description>
8208 <origin>jvmdi</origin>
8209 <capabilities>
8210 <required id="can_get_synthetic_attribute"></required>
8211 </capabilities>
8212 <parameters>
8213 <param id="klass">
8214 <jclass field="field"/>
8215 <description>
8216 The class of the field to query.
8217 </description>
8218 </param>
8219 <param id="field">
8220 <jfieldID class="klass"/>
8221 <description>
8222 The field to query.
8223 </description>
8224 </param>
8225 <param id="is_synthetic_ptr">
8226 <outptr><jboolean/></outptr>
8227 <description>
8228 On return, points to the boolean result of this function.
8229 </description>
8230 </param>
8231 </parameters>
8232 <errors>
8233 </errors>
8234 </function>
8235
8236 </category>
8237
8238 <category id="method" label="Method">
8239
8240 <intro>
8241 These functions provide information about a method (represented as a
8242 <typelink id="jmethodID"/>) and set how methods are processed.
8243 </intro>
8244
8245 <intro id="obsoleteMethods" label="Obsolete Methods">
8246 The functions <functionlink id="RetransformClasses"/> and
8247 <functionlink id="RedefineClasses"/> can cause new versions
8248 of methods to be installed.
8249 An original version of a method is considered equivalent
8250 to the new version if:
8251 <ul>
8252 <li>their bytecodes are the same except for indices into the
8253 constant pool and </li>
8254 <li>the referenced constants are equal.</li>
8255 </ul>
8256 An original method version which is not equivalent to the
8257 new method version is called obsolete and is assigned a new method ID;
8258 the original method ID now refers to the new method version.
8259 A method ID can be tested for obsolescence with
8260 <functionlink id="IsMethodObsolete"/>.
8261 </intro>
8262
8263 <function id="GetMethodName" phase="start" num="64">
8264 <synopsis>Get Method Name (and Signature)</synopsis>
8265 <description>
8266 For the method indicated by <code>method</code>,
8267 return the method name via <code>name_ptr</code> and method signature via
8268 <code>signature_ptr</code>.
8269 <p/>
8270 Method signatures are defined in the
8271 <externallink id="jni/index.html">JNI Specification</externallink>
8272 and are referred to as <code>method descriptors</code> in
8273 <vmspec chapter="4.3.3"/>.
8274 Note this is different
8275 than method signatures as defined in the <i>Java Language Specification</i>.
8276 </description>
8277 <origin>jvmdiClone</origin>
8278 <capabilities>
8279 </capabilities>
8280 <parameters>
8281 <param id="method">
8282 <jmethodID/>
8283 <description>
8284 The method to query.
8285 </description>
8286 </param>
8287 <param id="name_ptr">
8288 <allocbuf>
8289 <char/>
8290 <nullok>the name is not returned</nullok>
8291 </allocbuf>
8292 <description>
8293 On return, points to the method name, encoded as a
8294 <internallink id="mUTF">modified UTF-8</internallink> string.
8295 </description>
8296 </param>
8297 <param id="signature_ptr">
8298 <allocbuf>
8299 <char/>
8300 <nullok>the signature is not returned</nullok>
8301 </allocbuf>
8302 <description>
8303 On return, points to the method signature, encoded as a
8304 <internallink id="mUTF">modified UTF-8</internallink> string.
8305 </description>
8306 </param>
8307 <param id="generic_ptr">
8308 <allocbuf>
8309 <char/>
8310 <nullok>the generic signature is not returned</nullok>
8311 </allocbuf>
8312 <description>
8313 On return, points to the generic signature of the method, encoded as a
8314 <internallink id="mUTF">modified UTF-8</internallink> string.
8315 If there is no generic signature attribute for the method, then,
8316 on return, points to <code>NULL</code>.
8317 </description>
8318 </param>
8319 </parameters>
8320 <errors>
8321 </errors>
8322 </function>
8323
8324 <function id="GetMethodDeclaringClass" phase="start" num="65">
8325 <synopsis>Get Method Declaring Class</synopsis>
8326 <description>
8327 For the method indicated by <code>method</code>,
8328 return the class that defined it via <code>declaring_class_ptr</code>.
8329 </description>
8330 <origin>jvmdi</origin>
8331 <capabilities>
8332 </capabilities>
8333 <parameters>
8334 <param id="klass">
8335 <jclass method="method"/>
8336 <description>
8337 The class to query.
8338 </description>
8339 </param>
8340 <param id="method">
8341 <jmethodID class="klass"/>
8342 <description>
8343 The method to query.
8344 </description>
8345 </param>
8346 <param id="declaring_class_ptr">
8347 <outptr><jclass/></outptr>
8348 <description>
8349 On return, points to the declaring class
8350 </description>
8351 </param>
8352 </parameters>
8353 <errors>
8354 </errors>
8355 </function>
8356
8357 <function id="GetMethodModifiers" phase="start" num="66">
8358 <synopsis>Get Method Modifiers</synopsis>
8359 <description>
8360 For the method indicated by <code>method</code>,
8361 return the access flags via <code>modifiers_ptr</code>.
8362 Access flags are defined in <vmspec chapter="4"/>.
8363 </description>
8364 <origin>jvmdi</origin>
8365 <capabilities>
8366 </capabilities>
8367 <parameters>
8368 <param id="klass">
8369 <jclass method="method"/>
8370 <description>
8371 The class to query.
8372 </description>
8373 </param>
8374 <param id="method">
8375 <jmethodID class="klass"/>
8376 <description>
8377 The method to query.
8378 </description>
8379 </param>
8380 <param id="modifiers_ptr">
8381 <outptr><jint/></outptr>
8382 <description>
8383 On return, points to the access flags.
8384 </description>
8385 </param>
8386 </parameters>
8387 <errors>
8388 </errors>
8389 </function>
8390
8391 <function id="GetMaxLocals" phase="start" num="68">
8392 <synopsis>Get Max Locals</synopsis>
8393 <description>
8394 For the method indicated by <code>method</code>,
8395 return the number of local variable slots used by the method,
8396 including the local variables used to pass parameters to the
8397 method on its invocation.
8398 <p/>
8399 See <code>max_locals</code> in <vmspec chapter="4.7.3"/>.
8400 </description>
8401 <origin>jvmdi</origin>
8402 <capabilities>
8403 </capabilities>
8404 <parameters>
8405 <param id="klass">
8406 <jclass method="method"/>
8407 <description>
8408 The class to query.
8409 </description>
8410 </param>
8411 <param id="method">
8412 <jmethodID class="klass" native="error"/>
8413 <description>
8414 The method to query.
8415 </description>
8416 </param>
8417 <param id="max_ptr">
8418 <outptr><jint/></outptr>
8419 <description>
8420 On return, points to the maximum number of local slots
8421 </description>
8422 </param>
8423 </parameters>
8424 <errors>
8425 </errors>
8426 </function>
8427
8428 <function id="GetArgumentsSize" phase="start" num="69">
8429 <synopsis>Get Arguments Size</synopsis>
8430 <description>
8431 For the method indicated by <code>method</code>,
8432 return via <code>max_ptr</code> the number of local variable slots used
8433 by the method's arguments.
8434 Note that two-word arguments use two slots.
8435 </description>
8436 <origin>jvmdi</origin>
8437 <capabilities>
8438 </capabilities>
8439 <parameters>
8440 <param id="klass">
8441 <jclass method="method"/>
8442 <description>
8443 The class to query.
8444 </description>
8445 </param>
8446 <param id="method">
8447 <jmethodID class="klass" native="error"/>
8448 <description>
8449 The method to query.
8450 </description>
8451 </param>
8452 <param id="size_ptr">
8453 <outptr><jint/></outptr>
8454 <description>
8455 On return, points to the number of argument slots
8456 </description>
8457 </param>
8458 </parameters>
8459 <errors>
8460 </errors>
8461 </function>
8462
8463 <function id="GetLineNumberTable" phase="start" num="70">
8464 <synopsis>Get Line Number Table</synopsis>
8465 <typedef id="jvmtiLineNumberEntry" label="Line number table entry">
8466 <field id="start_location">
8467 <jlocation/>
8468 <description>
8469 the <datalink id="jlocation"></datalink> where the line begins
8470 </description>
8471 </field>
8472 <field id="line_number">
8473 <jint/>
8474 <description>
8475 the line number
8476 </description>
8477 </field>
8478 </typedef>
8479 <description>
8480 For the method indicated by <code>method</code>,
8481 return a table of source line number entries. The size of the table is
8482 returned via <code>entry_count_ptr</code> and the table itself is
8483 returned via <code>table_ptr</code>.
8484 </description>
8485 <origin>jvmdi</origin>
8486 <capabilities>
8487 <required id="can_get_line_numbers"></required>
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="entry_count_ptr">
8503 <outptr><jint/></outptr>
8504 <description>
8505 On return, points to the number of entries in the table
8506 </description>
8507 </param>
8508 <param id="table_ptr">
8509 <allocbuf outcount="entry_count_ptr"><struct>jvmtiLineNumberEntry</struct></allocbuf>
8510 <description>
8511 On return, points to the line number table pointer.
8512 </description>
8513 </param>
8514 </parameters>
8515 <errors>
8516 <error id="JVMTI_ERROR_ABSENT_INFORMATION">
8517 Class information does not include line numbers.
8518 </error>
8519 </errors>
8520 </function>
8521
8522 <function id="GetMethodLocation" phase="start" num="71">
8523 <synopsis>Get Method Location</synopsis>
8524 <description>
8525 For the method indicated by <code>method</code>,
8526 return the beginning and ending addresses through
8527 <code>start_location_ptr</code> and <code>end_location_ptr</code>. In a
8528 conventional byte code indexing scheme,
8529 <code>start_location_ptr</code> will always point to zero
8530 and <code>end_location_ptr</code>
8531 will always point to the byte code count minus one.
8532 </description>
8533 <origin>jvmdi</origin>
8534 <capabilities>
8535 </capabilities>
8536 <parameters>
8537 <param id="klass">
8538 <jclass method="method"/>
8539 <description>
8540 The class to query.
8541 </description>
8542 </param>
8543 <param id="method">
8544 <jmethodID class="klass" native="error"/>
8545 <description>
8546 The method to query.
8547 </description>
8548 </param>
8549 <param id="start_location_ptr">
8550 <outptr><jlocation/></outptr>
8551 <description>
8552 On return, points to the first location, or
8553 <code>-1</code> if location information is not available.
8554 If the information is available and
8555 <functionlink id="GetJLocationFormat"></functionlink>
8556 returns <datalink id="JVMTI_JLOCATION_JVMBCI"></datalink>
8557 then this will always be zero.
8558 </description>
8559 </param>
8560 <param id="end_location_ptr">
8561 <outptr><jlocation/></outptr>
8562 <description>
8563 On return, points to the last location,
8564 or <code>-1</code> if location information is not available.
8565 </description>
8566 </param>
8567 </parameters>
8568 <errors>
8569 <error id="JVMTI_ERROR_ABSENT_INFORMATION">
8570 Class information does not include method sizes.
8571 </error>
8572 </errors>
8573 </function>
8574
8575 <function id="GetLocalVariableTable" num="72">
8576 <synopsis>Get Local Variable Table</synopsis>
8577 <typedef id="jvmtiLocalVariableEntry" label="Local variable table entry">
8578 <field id="start_location">
8579 <jlocation/>
8580 <description>
8581 The code array index where the local variable is first valid
8582 (that is, where it must have a value).
8583 </description>
8584 </field>
8585 <field id="length">
8586 <jint/>
8587 <description>
8588 The length of the valid section for this local variable.
8589 The last code array index where the local variable is valid
8590 is <code>start_location + length</code>.
8591 </description>
8592 </field>
8593 <field id="name">
8594 <allocfieldbuf><char/></allocfieldbuf>
8595 <description>
8596 The local variable name, encoded as a
8597 <internallink id="mUTF">modified UTF-8</internallink> string.
8598 </description>
8599 </field>
8600 <field id="signature">
8601 <allocfieldbuf><char/></allocfieldbuf>
8602 <description>
8603 The local variable's type signature, encoded as a
8604 <internallink id="mUTF">modified UTF-8</internallink> string.
8605 The signature format is the same as that defined in
8606 <vmspec chapter="4.3.2"/>.
8607 </description>
8608 </field>
8609 <field id="generic_signature">
8610 <allocfieldbuf><char/></allocfieldbuf>
8611 <description>
8612 The local variable's generic signature, encoded as a
8613 <internallink id="mUTF">modified UTF-8</internallink> string.
8614 The value of this field will be <code>NULL</code> for any local
8615 variable which does not have a generic type.
8616 </description>
8617 </field>
8618 <field id="slot">
8619 <jint/>
8620 <description>
8621 The local variable's slot. See <internallink id="local">Local Variables</internallink>.
8622 </description>
8623 </field>
8624 </typedef>
8625 <description>
8626 Return local variable information.
8627 </description>
8628 <origin>jvmdiClone</origin>
8629 <capabilities>
8630 <required id="can_access_local_variables"></required>
8631 </capabilities>
8632 <parameters>
8633 <param id="method">
8634 <jmethodID native="error"/>
8635 <description>
8636 The method to query.
8637 </description>
8638 </param>
8639 <param id="entry_count_ptr">
8640 <outptr><jint/></outptr>
8641 <description>
8642 On return, points to the number of entries in the table
8643 </description>
8644 </param>
8645 <param id="table_ptr">
8646 <allocbuf outcount="entry_count_ptr"><struct>jvmtiLocalVariableEntry</struct></allocbuf>
8647 <description>
8648 On return, points to an array of local variable table entries.
8649 </description>
8650 </param>
8651 </parameters>
8652 <errors>
8653 <error id="JVMTI_ERROR_ABSENT_INFORMATION">
8654 Class information does not include local variable
8655 information.
8656 </error>
8657 </errors>
8658 </function>
8659
8660 <function id="GetBytecodes" phase="start" num="75">
8661 <synopsis>Get Bytecodes</synopsis>
8662 <description>
8663 For the method indicated by <code>method</code>,
8664 return the byte codes that implement the method. The number of
8665 bytecodes is returned via <code>bytecode_count_ptr</code>. The byte codes
8666 themselves are returned via <code>bytecodes_ptr</code>.
8667 </description>
8668 <origin>jvmdi</origin>
8669 <capabilities>
8670 <required id="can_get_bytecodes"></required>
8671 </capabilities>
8672 <parameters>
8673 <param id="klass">
8674 <jclass method="method"/>
8675 <description>
8676 The class to query.
8677 </description>
8678 </param>
8679 <param id="method">
8680 <jmethodID class="klass" native="error"/>
8681 <description>
8682 The method to query.
8683 </description>
8684 </param>
8685 <param id="bytecode_count_ptr">
8686 <outptr><jint/></outptr>
8687 <description>
8688 On return, points to the length of the byte code array
8689 </description>
8690 </param>
8691 <param id="bytecodes_ptr">
8692 <allocbuf outcount="bytecode_count_ptr"><uchar/></allocbuf>
8693 <description>
8694 On return, points to the pointer to the byte code array
8695 </description>
8696 </param>
8697 </parameters>
8698 <errors>
8699 </errors>
8700 </function>
8701
8702 <function id="IsMethodNative" phase="start" num="76">
8703 <synopsis>Is Method Native</synopsis>
8704 <description>
8705 For the method indicated by <code>method</code>, return a
8706 value indicating whether the method is native via <code>is_native_ptr</code>
8707 </description>
8708 <origin>jvmdi</origin>
8709 <capabilities>
8710 </capabilities>
8711 <parameters>
8712 <param id="klass">
8713 <jclass method="method"/>
8714 <description>
8715 The class to query.
8716 </description>
8717 </param>
8718 <param id="method">
8719 <jmethodID class="klass"/>
8720 <description>
8721 The method to query.
8722 </description>
8723 </param>
8724 <param id="is_native_ptr">
8725 <outptr><jboolean/></outptr>
8726 <description>
8727 On return, points to the boolean result of this function.
8728 </description>
8729 </param>
8730 </parameters>
8731 <errors>
8732 </errors>
8733 </function>
8734
8735 <function id="IsMethodSynthetic" phase="start" num="77">
8736 <synopsis>Is Method Synthetic</synopsis>
8737 <description>
8738 For the method indicated by <code>method</code>, return a
8739 value indicating whether the method is synthetic via <code>is_synthetic_ptr</code>.
8740 Synthetic methods are generated by the compiler but not present in the
8741 original source code.
8742 </description>
8743 <origin>jvmdi</origin>
8744 <capabilities>
8745 <required id="can_get_synthetic_attribute"></required>
8746 </capabilities>
8747 <parameters>
8748 <param id="klass">
8749 <jclass method="method"/>
8750 <description>
8751 The class to query.
8752 </description>
8753 </param>
8754 <param id="method">
8755 <jmethodID class="klass"/>
8756 <description>
8757 The method to query.
8758 </description>
8759 </param>
8760 <param id="is_synthetic_ptr">
8761 <outptr><jboolean/></outptr>
8762 <description>
8763 On return, points to the boolean result of this function.
8764 </description>
8765 </param>
8766 </parameters>
8767 <errors>
8768 </errors>
8769 </function>
8770
8771 <function id="IsMethodObsolete" phase="start" num="91">
8772 <synopsis>Is Method Obsolete</synopsis>
8773 <description>
8774 Determine if a method ID refers to an
8775 <internallink id="obsoleteMethods">obsolete</internallink>
8776 method version.
8777 </description>
8778 <origin>jvmdi</origin>
8779 <capabilities>
8780 </capabilities>
8781 <parameters>
8782 <param id="klass">
8783 <jclass method="method"/>
8784 <description>
8785 The class to query.
8786 </description>
8787 </param>
8788 <param id="method">
8789 <jmethodID class="klass"/>
8790 <description>
8791 The method ID to query.
8792 </description>
8793 </param>
8794 <param id="is_obsolete_ptr">
8795 <outptr><jboolean/></outptr>
8796 <description>
8797 On return, points to the boolean result of this function.
8798 </description>
8799 </param>
8800 </parameters>
8801 <errors>
8802 </errors>
8803 </function>
8804
8805 <function id="SetNativeMethodPrefix" jkernel="yes" phase="any" num="73" since="1.1">
8806 <synopsis>Set Native Method Prefix</synopsis>
8807 <description>
8808 This function modifies the failure handling of
8809 native method resolution by allowing retry
8810 with a prefix applied to the name.
8811 When used with the
8812 <eventlink id="ClassFileLoadHook">ClassFileLoadHook
8813 event</eventlink>, it enables native methods to be
8814 <internallink id="bci">instrumented</internallink>.
8815 <p/>
8816 Since native methods cannot be directly instrumented
8817 (they have no bytecodes), they must be wrapped with
8818 a non-native method which can be instrumented.
8819 For example, if we had:
8820 <example>
8821 native boolean foo(int x);</example>
8822 <p/>
8823 We could transform the class file (with the
8824 ClassFileLoadHook event) so that this becomes:
8825 <example>
8826 boolean foo(int x) {
8827 <i>... record entry to foo ...</i>
8828 return wrapped_foo(x);
8829 }
8830
8831 native boolean wrapped_foo(int x);</example>
8832 <p/>
8833 Where foo becomes a wrapper for the actual native method
8834 with the appended prefix "wrapped_". Note that
8835 "wrapped_" would be a poor choice of prefix since it
8836 might conceivably form the name of an existing method
8837 thus something like "$$$MyAgentWrapped$$$_" would be
8838 better but would make these examples less readable.
8839 <p/>
8840 The wrapper will allow data to be collected on the native
8841 method call, but now the problem becomes linking up the
8842 wrapped method with the native implementation.
8843 That is, the method <code>wrapped_foo</code> needs to be
8844 resolved to the native implementation of <code>foo</code>,
8845 which might be:
8846 <example>
8847 Java_somePackage_someClass_foo(JNIEnv* env, jint x)</example>
8848 <p/>
8849 This function allows the prefix to be specified and the
8850 proper resolution to occur.
8851 Specifically, when the standard resolution fails, the
8852 resolution is retried taking the prefix into consideration.
8853 There are two ways that resolution occurs, explicit
8854 resolution with the JNI function <code>RegisterNatives</code>
8855 and the normal automatic resolution. For
8856 <code>RegisterNatives</code>, the VM will attempt this
8857 association:
8858 <example>
8859 method(foo) -> nativeImplementation(foo)</example>
8860 <p/>
8861 When this fails, the resolution will be retried with
8862 the specified prefix prepended to the method name,
8863 yielding the correct resolution:
8864 <example>
8865 method(wrapped_foo) -> nativeImplementation(foo)</example>
8866 <p/>
8867 For automatic resolution, the VM will attempt:
8868 <example>
8869 method(wrapped_foo) -> nativeImplementation(wrapped_foo)</example>
8870 <p/>
8871 When this fails, the resolution will be retried with
8872 the specified prefix deleted from the implementation name,
8873 yielding the correct resolution:
8874 <example>
8875 method(wrapped_foo) -> nativeImplementation(foo)</example>
8876 <p/>
8877 Note that since the prefix is only used when standard
8878 resolution fails, native methods can be wrapped selectively.
8879 <p/>
8880 Since each <jvmti/> environment is independent and
8881 can do its own transformation of the bytecodes, more
8882 than one layer of wrappers may be applied. Thus each
8883 environment needs its own prefix. Since transformations
8884 are applied in order, the prefixes, if applied, will
8885 be applied in the same order.
8886 The order of transformation application is described in
8887 the <eventlink id="ClassFileLoadHook"/> event.
8888 Thus if three environments applied
8889 wrappers, <code>foo</code> might become
8890 <code>$env3_$env2_$env1_foo</code>. But if, say,
8891 the second environment did not apply a wrapper to
8892 <code>foo</code> it would be just
8893 <code>$env3_$env1_foo</code>. To be able to
8894 efficiently determine the sequence of prefixes,
8895 an intermediate prefix is only applied if its non-native
8896 wrapper exists. Thus, in the last example, even though
8897 <code>$env1_foo</code> is not a native method, the
8898 <code>$env1_</code> prefix is applied since
8899 <code>$env1_foo</code> exists.
8900 <p/>
8901 Since the prefixes are used at resolution time
8902 and since resolution may be arbitrarily delayed, a
8903 native method prefix must remain set as long as there
8904 are corresponding prefixed native methods.
8905 </description>
8906 <origin>new</origin>
8907 <capabilities>
8908 <required id="can_set_native_method_prefix"></required>
8909 </capabilities>
8910 <parameters>
8911 <param id="prefix">
8912 <inbuf>
8913 <char/>
8914 <nullok>
8915 any existing prefix in this environment is cancelled
8916 </nullok>
8917 </inbuf>
8918 <description>
8919 The prefix to apply, encoded as a
8920 <internallink id="mUTF">modified UTF-8</internallink> string.
8921 </description>
8922 </param>
8923 </parameters>
8924 <errors>
8925 </errors>
8926 </function>
8927
8928 <function id="SetNativeMethodPrefixes" jkernel="yes" phase="any" num="74" since="1.1">
8929 <synopsis>Set Native Method Prefixes</synopsis>
8930 <description>
8931 For a normal agent, <functionlink id="SetNativeMethodPrefix"/>
8932 will provide all needed native method prefixing.
8933 For a meta-agent that performs multiple independent class
8934 file transformations (for example as a proxy for another
8935 layer of agents) this function allows each transformation
8936 to have its own prefix.
8937 The prefixes are applied in the order supplied and are
8938 processed in the same manor as described for the
8939 application of prefixes from multiple <jvmti/> environments
8940 in <functionlink id="SetNativeMethodPrefix"/>.
8941 <p/>
8942 Any previous prefixes are replaced. Thus, calling this
8943 function with a <paramlink id="prefix_count"/> of <code>0</code>
8944 disables prefixing in this environment.
8945 <p/>
8946 <functionlink id="SetNativeMethodPrefix"/> and this function
8947 are the two ways to set the prefixes.
8948 Calling <code>SetNativeMethodPrefix</code> with
8949 a prefix is the same as calling this function with
8950 <paramlink id="prefix_count"/> of <code>1</code>.
8951 Calling <code>SetNativeMethodPrefix</code> with
8952 <code>NULL</code> is the same as calling this function with
8953 <paramlink id="prefix_count"/> of <code>0</code>.
8954 </description>
8955 <origin>new</origin>
8956 <capabilities>
8957 <required id="can_set_native_method_prefix"></required>
8958 </capabilities>
8959 <parameters>
8960 <param id="prefix_count">
8961 <jint min="0"/>
8962 <description>
8963 The number of prefixes to apply.
8964 </description>
8965 </param>
8966 <param id="prefixes">
8967 <agentbuf>
8968 <char/>
8969 </agentbuf>
8970 <description>
8971 The prefixes to apply for this environment, each encoded as a
8972 <internallink id="mUTF">modified UTF-8</internallink> string.
8973 </description>
8974 </param>
8975 </parameters>
8976 <errors>
8977 </errors>
8978 </function>
8979
8980 </category>
8981
8982 <category id="RawMonitors" label="Raw Monitor">
8983
8984 <function id="CreateRawMonitor" phase="onload" callbacksafe="safe" num="31">
8985 <synopsis>Create Raw Monitor</synopsis>
8986 <description>
8987 Create a raw monitor.
8988 </description>
8989 <origin>jvmdi</origin>
8990 <capabilities>
8991 </capabilities>
8992 <parameters>
8993 <param id="name">
8994 <inbuf><char/></inbuf>
8995 <description>
8996 A name to identify the monitor, encoded as a
8997 <internallink id="mUTF">modified UTF-8</internallink> string.
8998 </description>
8999 </param>
9000 <param id="monitor_ptr">
9001 <outptr><jrawMonitorID/></outptr>
9002 <description>
9003 On return, points to the created monitor.
9004 </description>
9005 </param>
9006 </parameters>
9007 <errors>
9008 </errors>
9009 </function>
9010
9011 <function id="DestroyRawMonitor" phase="onload" callbacksafe="safe" num="32">
9012 <synopsis>Destroy Raw Monitor</synopsis>
9013 <description>
9014 Destroy the raw monitor.
9015 If the monitor being destroyed has been entered by this thread, it will be
9016 exited before it is destroyed.
9017 If the monitor being destroyed has been entered by another thread,
9018 an error will be returned and the monitor will not be destroyed.
9019 </description>
9020 <origin>jvmdi</origin>
9021 <capabilities>
9022 </capabilities>
9023 <parameters>
9024 <param id="monitor">
9025 <jrawMonitorID/>
9026 <description>
9027 The monitor
9028 </description>
9029 </param>
9030 </parameters>
9031 <errors>
9032 <error id="JVMTI_ERROR_NOT_MONITOR_OWNER">
9033 Not monitor owner
9034 </error>
9035 </errors>
9036 </function>
9037
9038 <function id="RawMonitorEnter" phase="any" callbacksafe="safe" impl="innative notrace" num="33">
9039 <synopsis>Raw Monitor Enter</synopsis>
9040 <description>
9041 Gain exclusive ownership of a raw monitor.
9042 The same thread may enter a monitor more then once.
9043 The thread must
9044 <functionlink id="RawMonitorExit">exit</functionlink>
9045 the monitor the same number of times as it is entered.
9046 If a monitor is entered during <code>OnLoad</code> (before attached threads exist)
9047 and has not exited when attached threads come into existence, the enter
9048 is considered to have occurred on the main thread.
9049 </description>
9050 <origin>jvmdi</origin>
9051 <capabilities>
9052 </capabilities>
9053 <parameters>
9054 <param id="monitor">
9055 <jrawMonitorID/>
9056 <description>
9057 The monitor
9058 </description>
9059 </param>
9060 </parameters>
9061 <errors>
9062 </errors>
9063 </function>
9064
9065 <function id="RawMonitorExit" phase="any" callbacksafe="safe" impl="innative notrace" num="34">
9066 <synopsis>Raw Monitor Exit</synopsis>
9067 <description>
9068 Release exclusive ownership of a raw monitor.
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="RawMonitorWait" phase="any" callbacksafe="safe" impl="innative notrace" num="35">
9089 <synopsis>Raw Monitor Wait</synopsis>
9090 <description>
9091 Wait for notification of the raw monitor.
9092 <p/>
9093 Causes the current thread to wait until either another thread calls
9094 <functionlink id="RawMonitorNotify"/> or
9095 <functionlink id="RawMonitorNotifyAll"/>
9096 for the specified raw monitor, or the specified
9097 <paramlink id="millis">timeout</paramlink>
9098 has elapsed.
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 <param id="millis">
9111 <jlong/>
9112 <description>
9113 The timeout, in milliseconds. If the timeout is
9114 zero, then real time is not taken into consideration
9115 and the thread simply waits until notified.
9116 </description>
9117 </param>
9118 </parameters>
9119 <errors>
9120 <error id="JVMTI_ERROR_NOT_MONITOR_OWNER">
9121 Not monitor owner
9122 </error>
9123 <error id="JVMTI_ERROR_INTERRUPT">
9124 Wait was interrupted, try again
9125 </error>
9126 </errors>
9127 </function>
9128
9129 <function id="RawMonitorNotify" phase="any" callbacksafe="safe" impl="notrace" num="36">
9130 <synopsis>Raw Monitor Notify</synopsis>
9131 <description>
9132 Notify a single thread waiting on the raw monitor.
9133 </description>
9134 <origin>jvmdi</origin>
9135 <capabilities>
9136 </capabilities>
9137 <parameters>
9138 <param id="monitor">
9139 <jrawMonitorID/>
9140 <description>
9141 The monitor
9142 </description>
9143 </param>
9144 </parameters>
9145 <errors>
9146 <error id="JVMTI_ERROR_NOT_MONITOR_OWNER">
9147 Not monitor owner
9148 </error>
9149 </errors>
9150 </function>
9151
9152 <function id="RawMonitorNotifyAll" phase="any" callbacksafe="safe" impl="notrace" num="37">
9153 <synopsis>Raw Monitor Notify All</synopsis>
9154 <description>
9155 Notify all threads waiting on the raw monitor.
9156 </description>
9157 <origin>jvmdi</origin>
9158 <capabilities>
9159 </capabilities>
9160 <parameters>
9161 <param id="monitor">
9162 <jrawMonitorID/>
9163 <description>
9164 The monitor
9165 </description>
9166 </param>
9167 </parameters>
9168 <errors>
9169 <error id="JVMTI_ERROR_NOT_MONITOR_OWNER">
9170 Not monitor owner
9171 </error>
9172 </errors>
9173 </function>
9174
9175 <elide>
9176 <function id="GetRawMonitorUse" num="118">
9177 <synopsis>Get Raw Monitor Use</synopsis>
9178 <description>
9179 The fields of the <functionlink id="jvmtiMonitorUsage"></functionlink> structure
9180 are filled in with information about usage of the raw monitor.
9181 </description>
9182 <origin>new</origin>
9183 <capabilities>
9184 <required id="can_get_raw_monitor_usage"></required>
9185 </capabilities>
9186 <parameters>
9187 <param id="monitor">
9188 <jrawMonitorID/>
9189 <description>
9190 the raw monitor to query.
9191 </description>
9192 </param>
9193 <param id="info_ptr">
9194 <outptr><struct>jvmtiMonitorUsage</struct></outptr>
9195 <description>
9196 On return, filled with monitor information for the
9197 specified raw monitor.
9198 </description>
9199 </param>
9200 </parameters>
9201 <errors>
9202 </errors>
9203 </function>
9204
9205 <function id="GetRawMonitors" num="119">
9206 <synopsis>Get Raw Monitors</synopsis>
9207 <description>
9208 Return the list of raw monitors.
9209 <p/>
9210 Note: details about each monitor can be examined with
9211 <functionlink id="GetRawMonitorUse"></functionlink>.
9212 </description>
9213 <origin>new</origin>
9214 <capabilities>
9215 <required id="can_get_raw_monitor_usage"></required>
9216 </capabilities>
9217 <parameters>
9218 <param id="monitorCnt">
9219 <outptr><jint/></outptr>
9220 <description>
9221 On return, pointer to the number
9222 of monitors returned in <code>monitors_ptr</code>.
9223 </description>
9224 </param>
9225 <param id="monitors_ptr">
9226 <allocbuf outcount="monitorCnt"><jrawMonitorID/></allocbuf>
9227 <description>
9228 On return, pointer to the monitor list.
9229 </description>
9230 </param>
9231 </parameters>
9232 <errors>
9233 </errors>
9234 </function>
9235 </elide>
9236 </category>
9237
9238 <category id="jniIntercept" label="JNI Function Interception">
9239
9240 <intro>
9241 Provides the ability to intercept and resend
9242 Java Native Interface (JNI) function calls
9243 by manipulating the JNI function table.
9244 See <externallink id="jni/functions.html">JNI
9245 Functions</externallink> in the <i>Java Native Interface Specification</i>.
9246 <p/>
9247 The following example illustrates intercepting the
9248 <code>NewGlobalRef</code> JNI call in order to count reference
9249 creation.
9250 <example>
9251 JNIEnv original_jni_Functions;
9252 JNIEnv redirected_jni_Functions;
9253 int my_global_ref_count = 0;
9254
9255 jobject
9256 MyNewGlobalRef(JNIEnv *jni_env, jobject lobj) {
9257 ++my_global_ref_count;
9258 return originalJNIFunctions->NewGlobalRef(env, lobj);
9259 }
9260
9261 void
9262 myInit() {
9263 jvmtiError err;
9264
9265 err = (*jvmti_env)->GetJNIFunctionTable(jvmti_env, &original_jni_Functions);
9266 if (err != JVMTI_ERROR_NONE) {
9267 die();
9268 }
9269 err = (*jvmti_env)->GetJNIFunctionTable(jvmti_env, &redirected_jni_Functions);
9270 if (err != JVMTI_ERROR_NONE) {
9271 die();
9272 }
9273 redirectedJNIFunctions->NewGlobalRef = MyNewGlobalRef;
9274 err = (*jvmti_env)->SetJNIFunctionTable(jvmti_env, redirected_jni_Functions);
9275 if (err != JVMTI_ERROR_NONE) {
9276 die();
9277 }
9278 }
9279 </example>
9280 Sometime after <code>myInit</code> is called the user's JNI
9281 code is executed which makes the call to create a new global
9282 reference. Instead of going to the normal JNI implementation
9283 the call goes to <code>myNewGlobalRef</code>. Note that a
9284 copy of the original function table is kept so that the normal
9285 JNI function can be called after the data is collected.
9286 Note also that any JNI functions which are not overwritten
9287 will behave normally.
9288 <todo>
9289 check that the example compiles and executes.
9290 </todo>
9291 </intro>
9292
9293 <function id="SetJNIFunctionTable" phase="start" num="120">
9294 <synopsis>Set JNI Function Table</synopsis>
9295 <description>
9296 Set the JNI function table
9297 in all current and future JNI environments.
9298 As a result, all future JNI calls are directed to the specified functions.
9299 Use <functionlink id="GetJNIFunctionTable"></functionlink> to get the
9300 function table to pass to this function.
9301 For this function to take effect the the updated table entries must be
9302 used by the JNI clients.
9303 Since the table is defined <code>const</code> some compilers may optimize
9304 away the access to the table, thus preventing this function from taking
9305 effect.
9306 The table is copied--changes to the local copy of the
9307 table have no effect.
9308 This function affects only the function table, all other aspects of the environment are
9309 unaffected.
9310 See the examples <internallink id="jniIntercept">above</internallink>.
9311 </description>
9312 <origin>new</origin>
9313 <capabilities>
9314 </capabilities>
9315 <parameters>
9316 <param id="function_table">
9317 <inptr>
9318 <struct>jniNativeInterface</struct>
9319 </inptr>
9320 <description>
9321 Points to the new JNI function table.
9322 </description>
9323 </param>
9324 </parameters>
9325 <errors>
9326 </errors>
9327 </function>
9328
9329 <function id="GetJNIFunctionTable" phase="start" num="121">
9330 <synopsis>Get JNI Function Table</synopsis>
9331 <description>
9332 Get the JNI function table.
9333 The JNI function table is copied into allocated memory.
9334 If <functionlink id="SetJNIFunctionTable"></functionlink>
9335 has been called, the modified (not the original) function
9336 table is returned.
9337 Only the function table is copied, no other aspects of the environment
9338 are copied.
9339 See the examples <internallink id="jniIntercept">above</internallink>.
9340 </description>
9341 <origin>new</origin>
9342 <capabilities>
9343 </capabilities>
9344 <parameters>
9345 <param id="function_table">
9346 <allocbuf>
9347 <struct>jniNativeInterface</struct>
9348 </allocbuf>
9349 <description>
9350 On return, <code>*function_table</code>
9351 points a newly allocated copy of the JNI function table.
9352 </description>
9353 </param>
9354 </parameters>
9355 <errors>
9356 </errors>
9357 </function>
9358
9359 </category>
9360
9361 <category id="eventManagement" label="Event Management">
9362
9363 <function id="SetEventCallbacks" jkernel="yes" phase="onload" num="122">
9364 <synopsis>Set Event Callbacks</synopsis>
9365 <description>
9366 Set the functions to be called for each event.
9367 The callbacks are specified by supplying a replacement function table.
9368 The function table is copied--changes to the local copy of the
9369 table have no effect.
9370 This is an atomic action, all callbacks are set at once.
9371 No events are sent before this function is called.
9372 When an entry is <code>NULL</code> or when the event is beyond
9373 <paramlink id="size_of_callbacks"></paramlink> no event is sent.
9374 Details on events are
9375 described <internallink id="EventSection">later</internallink> in this document.
9376 An event must be enabled and have a callback in order to be
9377 sent--the order in which this function and
9378 <functionlink id="SetEventNotificationMode"></functionlink>
9379 are called does not affect the result.
9380 </description>
9381 <origin>new</origin>
9382 <capabilities>
9383 </capabilities>
9384 <parameters>
9385 <param id="callbacks">
9386 <inptr>
9387 <struct>jvmtiEventCallbacks</struct>
9388 <nullok>remove the existing callbacks</nullok>
9389 </inptr>
9390 <description>
9391 The new event callbacks.
9392 </description>
9393 </param>
9394 <param id="size_of_callbacks">
9395 <jint min="0"/>
9396 <description>
9397 <code>sizeof(jvmtiEventCallbacks)</code>--for version
9398 compatibility.
9399 </description>
9400 </param>
9401 </parameters>
9402 <errors>
9403 </errors>
9404 </function>
9405
9406 <function id="SetEventNotificationMode" jkernel="yes" phase="onload" num="2">
9407 <synopsis>Set Event Notification Mode</synopsis>
9408 <description>
9409 Control the generation of events.
9410 <constants id="jvmtiEventMode" label="Event Enable/Disable" kind="enum">
9411 <constant id="JVMTI_ENABLE" num="1">
9412 If <paramlink id="mode"></paramlink> is <code>JVMTI_ENABLE</code>,
9413 the event <paramlink id="event_type"></paramlink> will be enabled
9414 </constant>
9415 <constant id="JVMTI_DISABLE" num="0">
9416 If <paramlink id="mode"></paramlink> is <code>JVMTI_DISABLE</code>,
9417 the event <paramlink id="event_type"></paramlink> will be disabled
9418 </constant>
9419 </constants>
9420 If <code>event_thread</code> is <code>NULL</code>,
9421 the event is enabled or disabled globally; otherwise, it is
9422 enabled or disabled for a particular thread.
9423 An event is generated for
9424 a particular thread if it is enabled either at the thread or global
9425 levels.
9426 <p/>
9427 See <internallink id="EventIndex">below</internallink> for information on specific events.
9428 <p/>
9429 The following events cannot be controlled at the thread
9430 level through this function.
9431 <ul>
9432 <li><eventlink id="VMInit"></eventlink></li>
9433 <li><eventlink id="VMStart"></eventlink></li>
9434 <li><eventlink id="VMDeath"></eventlink></li>
9435 <li><eventlink id="ThreadStart"></eventlink></li>
9436 <li><eventlink id="CompiledMethodLoad"></eventlink></li>
9437 <li><eventlink id="CompiledMethodUnload"></eventlink></li>
9438 <li><eventlink id="DynamicCodeGenerated"></eventlink></li>
9439 <li><eventlink id="DataDumpRequest"></eventlink></li>
9440 </ul>
9441 <p/>
9442 Initially, no events are enabled at either the thread level
9443 or the global level.
9444 <p/>
9445 Any needed capabilities (see Event Enabling Capabilities below) must be possessed
9446 before calling this function.
9447 <p/>
9448 Details on events are
9449 described <internallink id="EventSection">below</internallink>.
9450 </description>
9451 <origin>jvmdiClone</origin>
9452 <eventcapabilities></eventcapabilities>
9453 <parameters>
9454 <param id="mode">
9455 <enum>jvmtiEventMode</enum>
9456 <description>
9457 <code>JVMTI_ENABLE</code> or <code>JVMTI_DISABLE</code>
9458 </description>
9459 </param>
9460 <param id="event_type">
9461 <enum>jvmtiEvent</enum>
9462 <description>
9463 the event to control
9464 </description>
9465 </param>
9466 <param id="event_thread">
9467 <ptrtype>
9468 <jthread impl="noconvert"/>
9469 <nullok>event is controlled at the global level</nullok>
9470 </ptrtype>
9471 <description>
9472 The thread to control
9473 </description>
9474 </param>
9475 <param id="...">
9476 <varargs/>
9477 <description>
9478 for future expansion
9479 </description>
9480 </param>
9481 </parameters>
9482 <errors>
9483 <error id="JVMTI_ERROR_INVALID_THREAD">
9484 <paramlink id="event_thread"/> is non-<code>NULL</code> and is not a valid thread.
9485 </error>
9486 <error id="JVMTI_ERROR_THREAD_NOT_ALIVE">
9487 <paramlink id="event_thread"/> is non-<code>NULL</code> and is not live (has not been started or is now dead).
9488 </error>
9489 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
9490 thread level control was attempted on events which do not
9491 permit thread level control.
9492 </error>
9493 <error id="JVMTI_ERROR_MUST_POSSESS_CAPABILITY">
9494 The Required Event Enabling Capability is not possessed.
9495 </error>
9496 </errors>
9497 </function>
9498
9499 <function id="GenerateEvents" num="123">
9500 <synopsis>Generate Events</synopsis>
9501 <description>
9502 Generate events to represent the current state of the VM.
9503 For example, if <paramlink id="event_type"/> is
9504 <code>JVMTI_EVENT_COMPILED_METHOD_LOAD</code>,
9505 a <eventlink id="CompiledMethodLoad"></eventlink> event will be
9506 sent for each currently compiled method.
9507 Methods that were loaded and now have been unloaded are not sent.
9508 The history of what events have previously been sent does not
9509 effect what events are sent by this function--for example,
9510 all currently compiled methods
9511 will be sent each time this function is called.
9512 <p/>
9513 This function is useful when
9514 events may have been missed due to the agent attaching after program
9515 execution begins; this function generates the missed events.
9516 <p/>
9517 Attempts to execute Java programming language code or
9518 JNI functions may be paused until this function returns -
9519 so neither should be called from the thread sending the event.
9520 This function returns only after the missed events have been
9521 sent, processed and have returned.
9522 The event may be sent on a different thread than the thread
9523 on which the event occurred.
9524 The callback for the event must be set with
9525 <functionlink id="SetEventCallbacks"></functionlink>
9526 and the event must be enabled with
9527 <functionlink id="SetEventNotificationMode"></functionlink>
9528 or the events will not occur.
9529 If the VM no longer has the information to generate some or
9530 all of the requested events, the events are simply not sent -
9531 no error is returned.
9532 <p/>
9533 Only the following events are supported:
9534 <ul>
9535 <li><eventlink id="CompiledMethodLoad"></eventlink></li>
9536 <li><eventlink id="DynamicCodeGenerated"></eventlink></li>
9537 </ul>
9538 </description>
9539 <origin>new</origin>
9540 <capabilities>
9541 <capability id="can_generate_compiled_method_load_events"></capability>
9542 </capabilities>
9543 <parameters>
9544 <param id="event_type">
9545 <enum>jvmtiEvent</enum>
9546 <description>
9547 The type of event to generate. Must be one of these:
9548 <ul>
9549 <li><eventlink id="CompiledMethodLoad"><code>JVMTI_EVENT_COMPILED_METHOD_LOAD</code></eventlink></li>
9550 <li><eventlink id="DynamicCodeGenerated"><code>JVMTI_EVENT_DYNAMIC_CODE_GENERATED</code></eventlink></li>
9551 </ul>
9552 </description>
9553 </param>
9554 </parameters>
9555 <errors>
9556 <error id="JVMTI_ERROR_MUST_POSSESS_CAPABILITY">
9557 <paramlink id="event_type"/> is
9558 <eventlink id="CompiledMethodLoad"><code>JVMTI_EVENT_COMPILED_METHOD_LOAD</code></eventlink>
9559 and <fieldlink id="can_generate_compiled_method_load_events" struct="jvmtiCapabilities"></fieldlink>
9560 is <code>false</code>.
9561 </error>
9562 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
9563 <paramlink id="event_type"/> is other than
9564 <eventlink id="CompiledMethodLoad"><code>JVMTI_EVENT_COMPILED_METHOD_LOAD</code></eventlink>
9565 or <eventlink id="DynamicCodeGenerated"><code>JVMTI_EVENT_DYNAMIC_CODE_GENERATED</code></eventlink>.
9566 </error>
9567 </errors>
9568 </function>
9569
9570 </category>
9571
9572 <category id="extension" label="Extension Mechanism">
9573
9574 <intro>
9575 These functions
9576 allow a <jvmti/> implementation to provide functions and events
9577 beyond those defined in this specification.
9578 <p/>
9579 Both extension functions and extension events have parameters
9580 each of which has a 'type' and 'kind' chosen from the following tables:
9581
9582 <constants id="jvmtiParamTypes" label="Extension Function/Event Parameter Types" kind="enum">
9583 <constant id="JVMTI_TYPE_JBYTE" num="101">
9584 Java programming language primitive type - <code>byte</code>.
9585 JNI type <code>jbyte</code>.
9586 </constant>
9587 <constant id="JVMTI_TYPE_JCHAR" num="102">
9588 Java programming language primitive type - <code>char</code>.
9589 JNI type <code>jchar</code>.
9590 </constant>
9591 <constant id="JVMTI_TYPE_JSHORT" num="103">
9592 Java programming language primitive type - <code>short</code>.
9593 JNI type <code>jshort</code>.
9594 </constant>
9595 <constant id="JVMTI_TYPE_JINT" num="104">
9596 Java programming language primitive type - <code>int</code>.
9597 JNI type <datalink id="jint"></datalink>.
9598 </constant>
9599 <constant id="JVMTI_TYPE_JLONG" num="105">
9600 Java programming language primitive type - <code>long</code>.
9601 JNI type <datalink id="jlong"></datalink>.
9602 </constant>
9603 <constant id="JVMTI_TYPE_JFLOAT" num="106">
9604 Java programming language primitive type - <code>float</code>.
9605 JNI type <datalink id="jfloat"></datalink>.
9606 </constant>
9607 <constant id="JVMTI_TYPE_JDOUBLE" num="107">
9608 Java programming language primitive type - <code>double</code>.
9609 JNI type <datalink id="jdouble"></datalink>.
9610 </constant>
9611 <constant id="JVMTI_TYPE_JBOOLEAN" num="108">
9612 Java programming language primitive type - <code>boolean</code>.
9613 JNI type <datalink id="jboolean"></datalink>.
9614 </constant>
9615 <constant id="JVMTI_TYPE_JOBJECT" num="109">
9616 Java programming language object type - <code>java.lang.Object</code>.
9617 JNI type <datalink id="jobject"></datalink>.
9618 Returned values are JNI local references and must be managed.
9619 </constant>
9620 <constant id="JVMTI_TYPE_JTHREAD" num="110">
9621 Java programming language object type - <code>java.lang.Thread</code>.
9622 <jvmti/> type <datalink id="jthread"></datalink>.
9623 Returned values are JNI local references and must be managed.
9624 </constant>
9625 <constant id="JVMTI_TYPE_JCLASS" num="111">
9626 Java programming language object type - <code>java.lang.Class</code>.
9627 JNI type <datalink id="jclass"></datalink>.
9628 Returned values are JNI local references and must be managed.
9629 </constant>
9630 <constant id="JVMTI_TYPE_JVALUE" num="112">
9631 Union of all Java programming language primitive and object types -
9632 JNI type <datalink id="jvalue"></datalink>.
9633 Returned values which represent object types are JNI local references and must be managed.
9634 </constant>
9635 <constant id="JVMTI_TYPE_JFIELDID" num="113">
9636 Java programming language field identifier -
9637 JNI type <datalink id="jfieldID"></datalink>.
9638 </constant>
9639 <constant id="JVMTI_TYPE_JMETHODID" num="114">
9640 Java programming language method identifier -
9641 JNI type <datalink id="jmethodID"></datalink>.
9642 </constant>
9643 <constant id="JVMTI_TYPE_CCHAR" num="115">
9644 C programming language type - <code>char</code>.
9645 </constant>
9646 <constant id="JVMTI_TYPE_CVOID" num="116">
9647 C programming language type - <code>void</code>.
9648 </constant>
9649 <constant id="JVMTI_TYPE_JNIENV" num="117">
9650 JNI environment - <code>JNIEnv</code>.
9651 Should be used with the correct <datalink id="jvmtiParamKind"/> to make it a pointer type.
9652 </constant>
9653 </constants>
9654
9655 <constants id="jvmtiParamKind" label="Extension Function/Event Parameter Kinds" kind="enum">
9656 <constant id="JVMTI_KIND_IN" num="91">
9657 Ingoing argument - <code>foo</code>.
9658 </constant>
9659 <constant id="JVMTI_KIND_IN_PTR" num="92">
9660 Ingoing pointer argument - <code>const foo*</code>.
9661 </constant>
9662 <constant id="JVMTI_KIND_IN_BUF" num="93">
9663 Ingoing array argument - <code>const foo*</code>.
9664 </constant>
9665 <constant id="JVMTI_KIND_ALLOC_BUF" num="94">
9666 Outgoing allocated array argument - <code>foo**</code>.
9667 Free with <code>Deallocate</code>.
9668 </constant>
9669 <constant id="JVMTI_KIND_ALLOC_ALLOC_BUF" num="95">
9670 Outgoing allocated array of allocated arrays argument - <code>foo***</code>.
9671 Free with <code>Deallocate</code>.
9672 </constant>
9673 <constant id="JVMTI_KIND_OUT" num="96">
9674 Outgoing argument - <code>foo*</code>.
9675 </constant>
9676 <constant id="JVMTI_KIND_OUT_BUF" num="97">
9677 Outgoing array argument (pre-allocated by agent) - <code>foo*</code>.
9678 Do not <code>Deallocate</code>.
9679 </constant>
9680 </constants>
9681
9682 </intro>
9683
9684 <typedef id="jvmtiParamInfo" label="Extension Function/Event Parameter Info">
9685 <field id="name">
9686 <allocfieldbuf><char/></allocfieldbuf>
9687 <description>
9688 The parameter name, encoded as a
9689 <internallink id="mUTF">modified UTF-8</internallink> string
9690 </description>
9691 </field>
9692 <field id="kind">
9693 <enum>jvmtiParamKind</enum>
9694 <description>
9695 The kind of the parameter - type modifiers
9696 </description>
9697 </field>
9698 <field id="base_type">
9699 <enum>jvmtiParamTypes</enum>
9700 <description>
9701 The base type of the parameter - modified by <code>kind</code>
9702 </description>
9703 </field>
9704 <field id="null_ok">
9705 <jboolean/>
9706 <description>
9707 Is a <code>NULL</code> argument permitted? Applies only to pointer and object types.
9708 </description>
9709 </field>
9710 </typedef>
9711
9712 <callback id="jvmtiExtensionFunction">
9713 <enum>jvmtiError</enum>
9714 <synopsis>Extension Function</synopsis>
9715 <description>
9716 This is the implementation-specific extension function.
9717 </description>
9718 <parameters>
9719 <param id="jvmti_env">
9720 <outptr>
9721 <struct>jvmtiEnv</struct>
9722 </outptr>
9723 <description>
9724 The <jvmti/> environment is the only fixed parameter for extension functions.
9725 </description>
9726 </param>
9727 <param id="...">
9728 <varargs/>
9729 <description>
9730 The extension function-specific parameters
9731 </description>
9732 </param>
9733 </parameters>
9734 </callback>
9735
9736 <function id="GetExtensionFunctions" phase="onload" num="124">
9737 <synopsis>Get Extension Functions</synopsis>
9738
9739 <typedef id="jvmtiExtensionFunctionInfo" label="Extension Function Info">
9740 <field id="func">
9741 <ptrtype>
9742 <struct>jvmtiExtensionFunction</struct>
9743 </ptrtype>
9744 <description>
9745 The actual function to call
9746 </description>
9747 </field>
9748 <field id="id">
9749 <allocfieldbuf><char/></allocfieldbuf>
9750 <description>
9751 The identifier for the extension function, encoded as a
9752 <internallink id="mUTF">modified UTF-8</internallink> string.
9753 Uses package name conventions.
9754 For example, <code>com.sun.hotspot.bar</code>
9755 </description>
9756 </field>
9757 <field id="short_description">
9758 <allocfieldbuf><char/></allocfieldbuf>
9759 <description>
9760 A one sentence description of the function, encoded as a
9761 <internallink id="mUTF">modified UTF-8</internallink> string.
9762 </description>
9763 </field>
9764 <field id="param_count">
9765 <jint/>
9766 <description>
9767 The number of parameters excluding <code>jvmtiEnv *jvmti_env</code>
9768 </description>
9769 </field>
9770 <field id="params">
9771 <allocfieldbuf outcount="param_count">
9772 <struct>jvmtiParamInfo</struct>
9773 </allocfieldbuf>
9774 <description>
9775 Array of
9776 <fieldlink id="param_count" struct="jvmtiExtensionFunctionInfo"></fieldlink>
9777 parameters (<code>jvmtiEnv *jvmti_env</code> excluded)
9778 </description>
9779 </field>
9780 <field id="error_count">
9781 <jint/>
9782 <description>
9783 The number of possible error returns (excluding universal errors)
9784 </description>
9785 </field>
9786 <field id="errors">
9787 <allocfieldbuf outcount="error_count">
9788 <enum>jvmtiError</enum>
9789 </allocfieldbuf>
9790 <description>
9791 Array of <fieldlink id="error_count" struct="jvmtiExtensionFunctionInfo"></fieldlink>
9792 possible errors
9793 </description>
9794 </field>
9795 </typedef>
9796
9797 <description>
9798 Returns the set of extension functions.
9799 </description>
9800 <origin>new</origin>
9801 <capabilities>
9802 </capabilities>
9803 <parameters>
9804 <param id="extension_count_ptr">
9805 <outptr><jint/></outptr>
9806 <description>
9807 On return, points to the number of extension functions
9808 </description>
9809 </param>
9810 <param id="extensions">
9811 <allocbuf outcount="extension_count_ptr"><struct>jvmtiExtensionFunctionInfo</struct></allocbuf>
9812 <description>
9813 Returns an array of extension function info, one per function
9814 </description>
9815 </param>
9816 </parameters>
9817 <errors>
9818 </errors>
9819 </function>
9820
9821 <function id="GetExtensionEvents" phase="onload" num="125">
9822 <synopsis>Get Extension Events</synopsis>
9823
9824 <typedef id="jvmtiExtensionEventInfo" label="Extension Event Info">
9825 <field id="extension_event_index">
9826 <jint/>
9827 <description>
9828 The identifying index of the event
9829 </description>
9830 </field>
9831 <field id="id">
9832 <allocfieldbuf><char/></allocfieldbuf>
9833 <description>
9834 The identifier for the extension event, encoded as a
9835 <internallink id="mUTF">modified UTF-8</internallink> string.
9836 Uses package name conventions.
9837 For example, <code>com.sun.hotspot.bar</code>
9838 </description>
9839 </field>
9840 <field id="short_description">
9841 <allocfieldbuf><char/></allocfieldbuf>
9842 <description>
9843 A one sentence description of the event, encoded as a
9844 <internallink id="mUTF">modified UTF-8</internallink> string.
9845 </description>
9846 </field>
9847 <field id="param_count">
9848 <jint/>
9849 <description>
9850 The number of parameters excluding <code>jvmtiEnv *jvmti_env</code>
9851 </description>
9852 </field>
9853 <field id="params">
9854 <allocfieldbuf outcount="param_count">
9855 <struct>jvmtiParamInfo</struct>
9856 </allocfieldbuf>
9857 <description>
9858 Array of
9859 <fieldlink id="param_count" struct="jvmtiExtensionEventInfo"></fieldlink>
9860 parameters (<code>jvmtiEnv *jvmti_env</code> excluded)
9861 </description>
9862 </field>
9863 </typedef>
9864
9865 <description>
9866 Returns the set of extension events.
9867 </description>
9868 <origin>new</origin>
9869 <capabilities>
9870 </capabilities>
9871 <parameters>
9872 <param id="extension_count_ptr">
9873 <outptr><jint/></outptr>
9874 <description>
9875 On return, points to the number of extension events
9876 </description>
9877 </param>
9878 <param id="extensions">
9879 <allocbuf outcount="extension_count_ptr"><struct>jvmtiExtensionEventInfo</struct></allocbuf>
9880 <description>
9881 Returns an array of extension event info, one per event
9882 </description>
9883 </param>
9884 </parameters>
9885 <errors>
9886 </errors>
9887 </function>
9888
9889 <callback id="jvmtiExtensionEvent">
9890 <void/>
9891 <synopsis>Extension Event</synopsis>
9892 <description>
9893 This is the implementation-specific event.
9894 The event handler is set with
9895 <functionlink id="SetExtensionEventCallback"/>.
9896 <p/>
9897 Event handlers for extension events must be declared varargs to match this definition.
9898 Failure to do so could result in calling convention mismatch and undefined behavior
9899 on some platforms.
9900 <p/>
9901 For example, if the <code>jvmtiParamInfo</code>
9902 returned by <functionlink id="GetExtensionEvents"/> indicates that
9903 there is a <code>jint</code> parameter, the event handler should be
9904 declared:
9905 <example>
9906 void JNICALL myHandler(jvmtiEnv* jvmti_env, jint myInt, ...)
9907 </example>
9908 Note the terminal "<code>...</code>" which indicates varargs.
9909 </description>
9910 <parameters>
9911 <param id="jvmti_env">
9912 <outptr>
9913 <struct>jvmtiEnv</struct>
9914 </outptr>
9915 <description>
9916 The <jvmti/> environment is the only fixed parameter for extension events.
9917 </description>
9918 </param>
9919 <param id="...">
9920 <varargs/>
9921 <description>
9922 The extension event-specific parameters
9923 </description>
9924 </param>
9925 </parameters>
9926 </callback>
9927
9928 <function id="SetExtensionEventCallback" phase="onload" num="126">
9929 <synopsis>Set Extension Event Callback</synopsis>
9930
9931 <description>
9932 Sets the callback function for an extension event and
9933 enables the event. Or, if the callback is <code>NULL</code>, disables
9934 the event. Note that unlike standard events, setting
9935 the callback and enabling the event are a single operation.
9936 </description>
9937 <origin>new</origin>
9938 <capabilities>
9939 </capabilities>
9940 <parameters>
9941 <param id="extension_event_index">
9942 <jint/>
9943 <description>
9944 Identifies which callback to set.
9945 This index is the
9946 <fieldlink id="extension_event_index" struct="jvmtiExtensionEventInfo"></fieldlink>
9947 field of
9948 <datalink id="jvmtiExtensionEventInfo"/>.
9949 </description>
9950 </param>
9951 <param id="callback">
9952 <ptrtype>
9953 <struct>jvmtiExtensionEvent</struct>
9954 <nullok>disable the event</nullok>
9955 </ptrtype>
9956 <description>
9957 If <code>callback</code> is non-<code>NULL</code>,
9958 set <code>callback</code> to be the event callback function
9959 and enable the event.
9960 </description>
9961 </param>
9962 </parameters>
9963 <errors>
9964 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
9965 <paramlink id="extension_event_index"/> is not an
9966 <fieldlink id="extension_event_index"
9967 struct="jvmtiExtensionEventInfo"/>
9968 returned by
9969 <functionlink id="GetExtensionEvents"/>
9970 </error>
9971 </errors>
9972 </function>
9973
9974 </category>
9975
9976 <category id="capability" label="Capability">
9977
9978 <intro>
9979 The capabilities functions allow you to change the
9980 functionality available to <jvmti/>--that is,
9981 which <jvmti/>
9982 functions can be called, what events can be generated,
9983 and what functionality these events and functions can
9984 provide.
9985 <p/>
9986 The "Capabilities" section of each function and event describe which
9987 capabilities, if any, they are associated with. "Required Functionality"
9988 means it is available for use and no capabilities must be added to use it.
9989 "Optional Functionality" means the agent must possess the capability
9990 before it can be used.
9991 To possess a capability, the agent must
9992 <functionlink id="AddCapabilities">add the capability</functionlink>.
9993 "Optional Features" describe capabilities which,
9994 if added, extend the feature set.
9995 <p/>
9996 The potentially available capabilities of each <jvmti/> implementation are different.
9997 Depending on the implementation, a capability:
9998 <ul>
9999 <li>may never be added</li>
10000 <li>may be added in either the <code>OnLoad</code> or live phase in any environment</li>
10001 <li>may be added only during the <code>OnLoad</code> phase</li>
10002 <li>may be possessed by only one environment at a time</li>
10003 <li>may be possessed by only one environment at a time,
10004 and only during the <code>OnLoad</code> phase</li>
10005 <li>and so on ...</li>
10006 </ul>
10007 Frequently, the addition of a capability may incur a cost in execution speed, start up
10008 time, and/or memory footprint. Note that the overhead of using a capability
10009 is completely different than the overhead of possessing a capability.
10010 Take single stepping as an example. When single stepping is on (that
10011 is, when the event is enabled and thus actively sending events)
10012 the overhead of sending and processing an event
10013 on each instruction is huge in any implementation.
10014 However, the overhead of possessing the capability may be small or large,
10015 depending on the implementation. Also, when and if a capability is potentially
10016 available depends on the implementation. Some examples:
10017 <ul>
10018 <li>One VM might perform all execution by compiling bytecodes into
10019 native code and be unable to generate single step instructions.
10020 In this implementation the capability can not be added.</li>
10021 <li>Another VM may be able to switch execution to a single stepping
10022 interpreter at any time. In this implementation, having the capability has no
10023 overhead and could be added at any time.</li>
10024 <li>Yet another VM might be able to choose a bytecode compiling or single stepping capable interpreted
10025 execution engine at start up, but be unable to switch between them.
10026 In this implementation the capability would need to be added
10027 during the <code>OnLoad</code> phase (before bytecode
10028 execution begins) and would have a large impact on execution speed
10029 even if single stepping was never used.</li>
10030 <li>Still another VM might be able to add an "is single stepping on" check
10031 into compiled bytecodes or a generated interpreter. Again in this implementation
10032 the capability would need to be added during the <code>OnLoad</code> phase but the overhead (a test
10033 and branch on each instruction) would be considerably less.</li>
10034 </ul>
10035 <p/>
10036 Each <jvmti/> <internallink id="environments">environment</internallink>
10037 has its own set of capabilities.
10038 Initially, that set is empty.
10039 Any desired capability must be added.
10040 If possible, capabilities should be added during the <code>OnLoad</code> phase. For most
10041 virtual machines certain capabilities require special set up for
10042 the virtual machine and this set up must happen
10043 during the <code>OnLoad</code> phase, before the virtual machine begins execution.
10044 Once a capability is added, it can
10045 only be removed if explicitly relinquished by the environment.
10046 <p/>
10047 The agent can,
10048 <functionlink id="GetPotentialCapabilities">determine what
10049 capabilities this VM can potentially provide</functionlink>,
10050 <functionlink id="AddCapabilities">add the capabilities
10051 to be used</functionlink>,
10052 <functionlink id="RelinquishCapabilities">release capabilities
10053 which are no longer needed</functionlink>, and
10054 <functionlink id="GetCapabilities">examine the currently available
10055 capabilities</functionlink>.
10056 </intro>
10057
10058 <intro id="capabilityExamples" label="Capability Examples">
10059 For example, a freshly started agent (in the <code>OnLoad</code> function)
10060 wants to enable all possible capabilities.
10061 Note that, in general, this is not advisable as the agent may suffer
10062 a performance penalty for functionality it is not using.
10063 The code might look like this in C:
10064 <example>
10065 jvmtiCapabilities capa;
10066 jvmtiError err;
10067
10068 err = (*jvmti)->GetPotentialCapabilities(jvmti, &capa);
10069 if (err == JVMTI_ERROR_NONE) {
10070 err = (*jvmti)->AddCapabilities(jvmti, &capa);
10071 </example>
10072 For example, if an agent wants to check if it can get
10073 the bytecodes of a method (that is, it wants to check
10074 if it previously added this capability and has not
10075 relinquished it), the code might
10076 look like this in C:
10077 <example>
10078 jvmtiCapabilities capa;
10079 jvmtiError err;
10080
10081 err = (*jvmti)->GetCapabilities(jvmti, &capa);
10082 if (err == JVMTI_ERROR_NONE) {
10083 if (capa.can_get_bytecodes) { ... } }
10084 </example>
10085 </intro>
10086
10087 <capabilitiestypedef id="jvmtiCapabilities" label="The Capabilities Structure">
10088 <description>
10089 The functions in this category use this capabilities structure
10090 which contains boolean flags corresponding to each capability:
10091 </description>
10092 <capabilityfield id="can_tag_objects">
10093 <description>
10094 Can set and get tags, as described in the
10095 <internallink id="Heap">Heap category</internallink>.
10096 </description>
10097 </capabilityfield>
10098 <capabilityfield id="can_generate_field_modification_events">
10099 <description>
10100 Can set watchpoints on field modification -
10101 <functionlink id="SetFieldModificationWatch"></functionlink>
10102 </description>
10103 </capabilityfield>
10104 <capabilityfield id="can_generate_field_access_events">
10105 <description>
10106 Can set watchpoints on field access -
10107 <functionlink id="SetFieldAccessWatch"></functionlink>
10108 </description>
10109 </capabilityfield>
10110 <capabilityfield id="can_get_bytecodes">
10111 <description>
10112 Can get bytecodes of a method <functionlink id="GetBytecodes"></functionlink>
10113 </description>
10114 </capabilityfield>
10115 <capabilityfield id="can_get_synthetic_attribute">
10116 <description>
10117 Can test if a field or method is synthetic -
10118 <functionlink id="IsFieldSynthetic"></functionlink> and
10119 <functionlink id="IsMethodSynthetic"></functionlink>
10120 </description>
10121 </capabilityfield>
10122 <capabilityfield id="can_get_owned_monitor_info">
10123 <description>
10124 Can get information about ownership of monitors -
10125 <functionlink id="GetOwnedMonitorInfo"></functionlink>
10126 </description>
10127 </capabilityfield>
10128 <capabilityfield id="can_get_current_contended_monitor">
10129 <description>
10130 Can <functionlink id="GetCurrentContendedMonitor"></functionlink>
10131 </description>
10132 </capabilityfield>
10133 <capabilityfield id="can_get_monitor_info">
10134 <description>
10135 Can <functionlink id="GetObjectMonitorUsage"></functionlink>
10136 </description>
10137 </capabilityfield>
10138 <capabilityfield id="can_pop_frame">
10139 <description>
10140 Can pop frames off the stack - <functionlink id="PopFrame"></functionlink>
10141 </description>
10142 </capabilityfield>
10143 <capabilityfield id="can_redefine_classes">
10144 <description>
10145 Can redefine classes with <functionlink id="RedefineClasses"/>.
10146 </description>
10147 </capabilityfield>
10148 <capabilityfield id="can_signal_thread">
10149 <description>
10150 Can send stop or interrupt to threads
10151 </description>
10152 </capabilityfield>
10153 <capabilityfield id="can_get_source_file_name">
10154 <description>
10155 Can get the source file name of a class
10156 </description>
10157 </capabilityfield>
10158 <capabilityfield id="can_get_line_numbers">
10159 <description>
10160 Can get the line number table of a method
10161 </description>
10162 </capabilityfield>
10163 <capabilityfield id="can_get_source_debug_extension">
10164 <description>
10165 Can get the source debug extension of a class
10166 </description>
10167 </capabilityfield>
10168 <capabilityfield id="can_access_local_variables">
10169 <description>
10170 Can set and get local variables
10171 </description>
10172 </capabilityfield>
10173 <capabilityfield id="can_maintain_original_method_order">
10174 <description>
10175 Can return methods in the order they occur in the class file
10176 </description>
10177 </capabilityfield>
10178 <capabilityfield id="can_generate_single_step_events">
10179 <description>
10180 Can get <eventlink id="SingleStep">single step</eventlink> events
10181 </description>
10182 </capabilityfield>
10183 <capabilityfield id="can_generate_exception_events">
10184 <description>
10185 Can get <eventlink id="Exception">exception thrown</eventlink> and
10186 <eventlink id="ExceptionCatch">exception catch</eventlink> events
10187 </description>
10188 </capabilityfield>
10189 <capabilityfield id="can_generate_frame_pop_events">
10190 <description>
10191 Can <functionlink id="NotifyFramePop">set</functionlink> and thus get
10192 <eventlink id="FramePop"></eventlink> events
10193 </description>
10194 </capabilityfield>
10195 <capabilityfield id="can_generate_breakpoint_events">
10196 <description>
10197 Can <functionlink id="SetBreakpoint">set</functionlink> and thus get
10198 <eventlink id="Breakpoint"></eventlink> events
10199 </description>
10200 </capabilityfield>
10201 <capabilityfield id="can_suspend">
10202 <description>
10203 Can suspend and resume threads
10204 </description>
10205 </capabilityfield>
10206 <capabilityfield id="can_redefine_any_class">
10207 <description>
10208 Can modify (retransform or redefine) any modifiable class.
10209 See <functionlink id="IsModifiableClass"/>.
10210 </description>
10211 </capabilityfield>
10212 <capabilityfield id="can_get_current_thread_cpu_time">
10213 <description>
10214 Can <functionlink id="GetCurrentThreadCpuTime">get</functionlink>
10215 current thread CPU time
10216 </description>
10217 </capabilityfield>
10218 <capabilityfield id="can_get_thread_cpu_time">
10219 <description>
10220 Can <functionlink id="GetThreadCpuTime">get</functionlink>
10221 thread CPU time
10222 </description>
10223 </capabilityfield>
10224 <capabilityfield id="can_generate_method_entry_events"
10225 disp1="can_generate" disp2="_method_entry_events"
10226 >
10227 <description>
10228 Can generate method entry events on entering a method
10229 </description>
10230 </capabilityfield>
10231 <capabilityfield id="can_generate_method_exit_events"
10232 disp1="can_generate" disp2="_method_exit_events"
10233 >
10234 <description>
10235 Can generate method exit events on leaving a method
10236 </description>
10237 </capabilityfield>
10238 <capabilityfield id="can_generate_all_class_hook_events"
10239 disp1="can_generate" disp2="_all_class_hook_events"
10240 >
10241 <description>
10242 Can generate ClassFileLoadHook events for every loaded class.
10243 </description>
10244 </capabilityfield>
10245 <capabilityfield id="can_generate_compiled_method_load_events"
10246 disp1="can_generate" disp2="_compiled_method_load_events"
10247 >
10248 <description>
10249 Can generate events when a method is compiled or unloaded
10250 </description>
10251 </capabilityfield>
10252 <capabilityfield id="can_generate_monitor_events"
10253 disp1="can_generate" disp2="_monitor_events"
10254 >
10255 <description>
10256 Can generate events on monitor activity
10257 </description>
10258 </capabilityfield>
10259 <capabilityfield id="can_generate_vm_object_alloc_events"
10260 disp1="can_generate" disp2="_vm_object_alloc_events"
10261 >
10262 <description>
10263 Can generate events on VM allocation of an object
10264 </description>
10265 </capabilityfield>
10266 <capabilityfield id="can_generate_native_method_bind_events"
10267 disp1="can_generate" disp2="_native_method_bind_events"
10268 >
10269 <description>
10270 Can generate events when a native method is bound to its
10271 implementation
10272 </description>
10273 </capabilityfield>
10274 <capabilityfield id="can_generate_garbage_collection_events"
10275 disp1="can_generate" disp2="_garbage_collection_events"
10276 >
10277 <description>
10278 Can generate events when garbage collection begins or ends
10279 </description>
10280 </capabilityfield>
10281 <capabilityfield id="can_generate_object_free_events"
10282 disp1="can_generate" disp2="_object_free_events"
10283 >
10284 <description>
10285 Can generate events when the garbage collector frees an object
10286 </description>
10287 </capabilityfield>
10288 <capabilityfield id="can_force_early_return" since="1.1">
10289 <description>
10290 Can return early from a method, as described in the
10291 <internallink id="ForceEarlyReturn">Force Early Return category</internallink>.
10292 </description>
10293 </capabilityfield>
10294 <capabilityfield id="can_get_owned_monitor_stack_depth_info" since="1.1">
10295 <description>
10296 Can get information about owned monitors with stack depth -
10297 <functionlink id="GetOwnedMonitorStackDepthInfo"></functionlink>
10298 </description>
10299 </capabilityfield>
10300 <capabilityfield id="can_get_constant_pool" since="1.1">
10301 <description>
10302 Can get the constant pool of a class -
10303 <functionlink id="GetConstantPool"></functionlink>
10304 </description>
10305 </capabilityfield>
10306 <capabilityfield id="can_set_native_method_prefix" since="1.1">
10307 <description>
10308 Can set prefix to be applied when native method cannot be resolved -
10309 <functionlink id="SetNativeMethodPrefix"/> and
10310 <functionlink id="SetNativeMethodPrefixes"/>
10311 </description>
10312 </capabilityfield>
10313 <capabilityfield id="can_retransform_classes" since="1.1">
10314 <description>
10315 Can retransform classes with <functionlink id="RetransformClasses"/>.
10316 In addition to the restrictions imposed by the specific
10317 implementation on this capability (see the
10318 <internallink id="capability">Capability</internallink> section),
10319 this capability must be set before the
10320 <eventlink id="ClassFileLoadHook"/> event is enabled for the
10321 first time in this environment.
10322 An environment that possesses this capability at the time that
10323 <code>ClassFileLoadHook</code> is enabled for the first time is
10324 said to be <i>retransformation capable</i>.
10325 An environment that does not possess this capability at the time that
10326 <code>ClassFileLoadHook</code> is enabled for the first time is
10327 said to be <i>retransformation incapable</i>.
10328 </description>
10329 </capabilityfield>
10330 <capabilityfield id="can_retransform_any_class" since="1.1">
10331 <description>
10332 <functionlink id="RetransformClasses"/> can be called on any modifiable class.
10333 See <functionlink id="IsModifiableClass"/>.
10334 (<fieldlink id="can_retransform_classes" struct="jvmtiCapabilities"/>
10335 must also be set)
10336 </description>
10337 </capabilityfield>
10338 <capabilityfield id="can_generate_resource_exhaustion_heap_events" since="1.1">
10339 <description>
10340 Can generate events when the VM is unable to allocate memory from
10341 the <tm>Java</tm> platform heap.
10342 See <eventlink id="ResourceExhausted"/>.
10343 </description>
10344 </capabilityfield>
10345 <capabilityfield id="can_generate_resource_exhaustion_threads_events" since="1.1">
10346 <description>
10347 Can generate events when the VM is unable to create a thread.
10348 See <eventlink id="ResourceExhausted"/>.
10349 </description>
10350 </capabilityfield>
10351 <capabilityfield id="can_generate_early_vmstart" since="9">
10352 <description>
10353 Can generate the <code>VMStart</code> event early.
10354 See <eventlink id="VMStart"/>.
10355 </description>
10356 </capabilityfield>
10357 <capabilityfield id="can_generate_early_class_hook_events" since="9">
10358 <description>
10359 Can generate the <eventlink id="ClassFileLoadHook"/> events
10360 in the primordial phase. If this capability and
10361 <internallink id="jvmtiCapabilities.can_generate_all_class_hook_events">
10362 <code>can_generate_all_class_hook_events</code></internallink>
10363 are enabled then the <eventlink id="ClassFileLoadHook"/> events
10364 can be posted for classes loaded in the primordial phase.
10365 See <eventlink id="ClassFileLoadHook"/>.
10366 </description>
10367 </capabilityfield>
10368 </capabilitiestypedef>
10369
10370 <function id="GetPotentialCapabilities" jkernel="yes" phase="onload" num="140">
10371 <synopsis>Get Potential Capabilities</synopsis>
10372 <description>
10373 Returns via <paramlink id="capabilities_ptr"></paramlink> the <jvmti/>
10374 features that can potentially be possessed by this environment
10375 at this time.
10376 The returned capabilities differ from the complete set of capabilities
10377 implemented by the VM in two cases: another environment possesses
10378 capabilities that can only be possessed by one environment, or the
10379 current <functionlink id="GetPhase">phase</functionlink> is live,
10380 and certain capabilities can only be added during the <code>OnLoad</code> phase.
10381 The <functionlink id="AddCapabilities"></functionlink> function
10382 may be used to set any or all or these capabilities.
10383 Currently possessed capabilities are included.
10384 <p/>
10385 Typically this function is used in the <code>OnLoad</code> function.
10386 Some virtual machines may allow a limited set of capabilities to be
10387 added in the live phase.
10388 In this case, the set of potentially available capabilities
10389 will likely differ from the <code>OnLoad</code> phase set.
10390 <p/>
10391 See the
10392 <internallink id="capabilityExamples">Capability Examples</internallink>.
10393 </description>
10394 <origin>new</origin>
10395 <capabilities>
10396 </capabilities>
10397 <parameters>
10398 <param id="capabilities_ptr">
10399 <outptr><struct>jvmtiCapabilities</struct></outptr>
10400 <description>
10401 On return, points to the <jvmti/> capabilities that may be added.
10402 </description>
10403 </param>
10404 </parameters>
10405 <errors>
10406 </errors>
10407 </function>
10408
10409 <elide>
10410 <function id="EstimateCostOfCapabilities" phase="onload" num="141">
10411 <synopsis>Estimate Cost Of Capabilities</synopsis>
10412 <description>
10413 <issue>There is strong opposition to this function. The concern is
10414 that it would be difficult or impossible to provide meaningful
10415 numbers, as the amount of impact is conditional on many factors
10416 that a single number could not represent. There is doubt that
10417 conditional implementations would be used or are even a good idea.
10418 The thought is that release documentation for the implementation
10419 would be the best means of exposing this information.
10420 Unless new arguments are presented, I intend to remove this
10421 function in the next revision.
10422 </issue>
10423 <p/>
10424 Return via the <paramlink id="time_impact_ptr"></paramlink> and
10425 <paramlink id="space_impact_ptr"></paramlink> an estimate of the impact
10426 of adding the capabilities pointed to by
10427 <paramlink id="capabilities_ptr"></paramlink>.
10428 The returned estimates are in percentage of additional overhead, thus
10429 a time impact of 100 mean the application might run
10430 at half the speed.
10431 The estimates are very rough approximations and are not guaranteed.
10432 Note also, that the estimates are of the impact of having the
10433 capability available--when and if it is used the impact may be
10434 much greater.
10435 Estimates can be for a single capability or for a set of
10436 capabilities. Note that the costs are not necessarily additive,
10437 adding support for one capability might make another available
10438 for free or conversely having two capabilities at once may
10439 have multiplicative impact.
10440 Estimates are relative to the current set of capabilities -
10441 that is, how much more impact given the currently possessed capabilities.
10442 <p/>
10443 Typically this function is used in the OnLoad function,
10444 some virtual machines may allow a limited set of capabilities to be
10445 added in the live phase.
10446 In this case, the set of potentially available capabilities
10447 will likely differ from the OnLoad phase set.
10448 <p/>
10449 See the
10450 <internallink id="capabilityExamples">Capability Examples</internallink>.
10451 </description>
10452 <origin>new</origin>
10453 <capabilities>
10454 </capabilities>
10455 <parameters>
10456 <param id="capabilities_ptr">
10457 <inptr><struct>jvmtiCapabilities</struct></inptr>
10458 <description>
10459 points to the <jvmti/> capabilities to evaluate.
10460 </description>
10461 </param>
10462 <param id="time_impact_ptr">
10463 <outptr><jint/></outptr>
10464 <description>
10465 On return, points to the estimated percentage increase in
10466 run time if this capability was added.
10467 </description>
10468 </param>
10469 <param id="space_impact_ptr">
10470 <outptr><jint/></outptr>
10471 <description>
10472 On return, points to the estimated percentage increase in
10473 memory space used if this capability was added.
10474 </description>
10475 </param>
10476 </parameters>
10477 <errors>
10478 <error id="JVMTI_ERROR_NOT_AVAILABLE">
10479 The desired capabilities are not even potentially available.
10480 </error>
10481 </errors>
10482 </function>
10483 </elide>
10484
10485 <function id="AddCapabilities" jkernel="yes" phase="onload" num="142">
10486 <synopsis>Add Capabilities</synopsis>
10487 <description>
10488 Set new capabilities by adding the capabilities
10489 whose values are set to one (<code>1</code>) in
10490 <code>*</code><paramlink id="capabilities_ptr"></paramlink>.
10491 All previous capabilities are retained.
10492 Typically this function is used in the <code>OnLoad</code> function.
10493 Some virtual machines may allow a limited set of capabilities to be
10494 added in the live phase.
10495 <p/>
10496 See the
10497 <internallink id="capabilityExamples">Capability Examples</internallink>.
10498 </description>
10499 <origin>new</origin>
10500 <capabilities>
10501 </capabilities>
10502 <parameters>
10503 <param id="capabilities_ptr">
10504 <inptr><struct>jvmtiCapabilities</struct></inptr>
10505 <description>
10506 Points to the <jvmti/> capabilities to add.
10507 </description>
10508 </param>
10509 </parameters>
10510 <errors>
10511 <error id="JVMTI_ERROR_NOT_AVAILABLE">
10512 The desired capabilities are not even potentially available.
10513 </error>
10514 </errors>
10515 </function>
10516
10517
10518 <function id="RelinquishCapabilities" phase="onload" num="143">
10519 <synopsis>Relinquish Capabilities</synopsis>
10520 <description>
10521 Relinquish the capabilities
10522 whose values are set to one (<code>1</code>) in
10523 <code>*</code><paramlink id="capabilities_ptr"></paramlink>.
10524 Some implementations may allow only one environment to have a capability
10525 (see the <internallink id="capability">capability introduction</internallink>).
10526 This function releases capabilities
10527 so that they may be used by other agents.
10528 All other capabilities are retained.
10529 The capability will no longer be present in <functionlink id="GetCapabilities"></functionlink>.
10530 Attempting to relinquish a capability that the agent does not possess is not an error.
10531 <issue>
10532 It is possible for the agent to be actively using capabilities
10533 which are being relinquished. For example, a thread is currently
10534 suspended and can_suspend is being relinquished or an event is currently
10535 enabled and can_generate_whatever is being relinquished.
10536 There are three possible ways we could spec this:
10537 <ul>
10538 <li>relinquish automatically releases them</li>
10539 <li>relinquish checks and returns some error code if held</li>
10540 <li>it is the agent's responsibility and it is not checked</li>
10541 </ul>
10542 One of these should be chosen.
10543 </issue>
10544 </description>
10545 <origin>new</origin>
10546 <capabilities>
10547 </capabilities>
10548 <parameters>
10549 <param id="capabilities_ptr">
10550 <inptr><struct>jvmtiCapabilities</struct></inptr>
10551 <description>
10552 Points to the <jvmti/> capabilities to relinquish.
10553 </description>
10554 </param>
10555 </parameters>
10556 <errors>
10557 </errors>
10558 </function>
10559
10560
10561
10562 <function id="GetCapabilities" jkernel="yes" phase="any" num="89">
10563 <synopsis>Get Capabilities</synopsis>
10564 <description>
10565 Returns via <paramlink id="capabilities_ptr"></paramlink> the optional <jvmti/>
10566 features which this environment currently possesses.
10567 Each possessed capability is indicated by a one (<code>1</code>) in the
10568 corresponding field of the <internallink id="jvmtiCapabilities">capabilities
10569 structure</internallink>.
10570 An environment does not possess a capability unless it has been successfully added with
10571 <functionlink id="AddCapabilities"/>.
10572 An environment only loses possession of a capability if it has been relinquished with
10573 <functionlink id="RelinquishCapabilities"/>. Thus, this function returns the net result
10574 of the <code>AddCapabilities</code> and <code>RelinquishCapabilities</code> calls which
10575 have been made.
10576 <p/>
10577 See the
10578 <internallink id="capabilityExamples">Capability Examples</internallink>.
10579 </description>
10580 <origin>jvmdiClone</origin>
10581 <capabilities>
10582 </capabilities>
10583 <parameters>
10584 <param id="capabilities_ptr">
10585 <outptr><struct>jvmtiCapabilities</struct></outptr>
10586 <description>
10587 On return, points to the <jvmti/> capabilities.
10588 </description>
10589 </param>
10590 </parameters>
10591 <errors>
10592 </errors>
10593 </function>
10594
10595 </category>
10596
10597
10598 <category id="timers" label="Timers">
10599
10600 <intro>
10601 These functions provide timing information.
10602 The resolution at which the time is updated is not specified.
10603 They provides nanosecond precision, but not necessarily nanosecond accuracy.
10604 Details about the timers, such as their maximum values, can be accessed with
10605 the timer information functions.
10606 </intro>
10607
10608 <typedef id="jvmtiTimerInfo" label="Timer Info">
10609 <description>
10610 The information function for each timer returns this data structure.
10611 </description>
10612 <field id="max_value">
10613 <jlong/>
10614 <description>
10615 The maximum value the timer can reach.
10616 After this value is reached the timer wraps back to zero.
10617 This is an unsigned value. If tested or printed as a jlong (signed value)
10618 it may appear to be a negative number.
10619 </description>
10620 </field>
10621 <field id="may_skip_forward">
10622 <jboolean/>
10623 <description>
10624 If true, the timer can be externally adjusted and as a result skip forward.
10625 If false, the timer value will never increase faster than real time.
10626 </description>
10627 </field>
10628 <field id="may_skip_backward">
10629 <jboolean/>
10630 <description>
10631 If true, the timer can be externally adjusted and as a result skip backward.
10632 If false, the timer value will be monotonically increasing.
10633 </description>
10634 </field>
10635 <field id="kind">
10636 <enum>jvmtiTimerKind</enum>
10637 <description>
10638 The kind of timer.
10639 On a platform that does not distinguish between user and system time, <datalink
10640 id="JVMTI_TIMER_TOTAL_CPU"><code>JVMTI_TIMER_TOTAL_CPU</code></datalink>
10641 is returned.
10642 </description>
10643 </field>
10644 <field id="reserved1">
10645 <jlong/>
10646 <description>
10647 Reserved for future use.
10648 </description>
10649 </field>
10650 <field id="reserved2">
10651 <jlong/>
10652 <description>
10653 Reserved for future use.
10654 </description>
10655 </field>
10656 </typedef>
10657
10658 <intro>
10659 Where the timer kind is --
10660
10661 <constants id="jvmtiTimerKind" label="Timer Kinds" kind="enum">
10662 <constant id="JVMTI_TIMER_USER_CPU" num="30">
10663 CPU time that a thread is in user mode.
10664 </constant>
10665 <constant id="JVMTI_TIMER_TOTAL_CPU" num="31">
10666 CPU time that a thread is in user or system mode.
10667 </constant>
10668 <constant id="JVMTI_TIMER_ELAPSED" num="32">
10669 Elapsed time.
10670 </constant>
10671 </constants>
10672 </intro>
10673
10674 <function id="GetCurrentThreadCpuTimerInfo" callbacksafe="safe" impl="innative notrace" phase="start" num="134">
10675 <synopsis>Get Current Thread CPU Timer Information</synopsis>
10676 <description>
10677 Get information about the
10678 <functionlink id="GetCurrentThreadCpuTime"/> timer.
10679 The fields of the <datalink id="jvmtiTimerInfo"/> structure
10680 are filled in with details about the timer.
10681 This information is specific to the platform and the implementation of
10682 <functionlink id="GetCurrentThreadCpuTime"/> and thus
10683 does not vary by thread nor does it vary
10684 during a particular invocation of the VM.
10685 <p/>
10686 Note that the implementations of <functionlink id="GetCurrentThreadCpuTime"/>
10687 and <functionlink id="GetThreadCpuTime"/> may differ, and thus the values
10688 returned by <code>GetCurrentThreadCpuTimerInfo</code>
10689 and <functionlink id="GetThreadCpuTimerInfo"/>
10690 may differ -- see <functionlink id="GetCurrentThreadCpuTime"/> for more information.
10691 </description>
10692 <origin>new</origin>
10693 <capabilities>
10694 <required id="can_get_current_thread_cpu_time">
10695 Can get current thread CPU time.
10696 </required>
10697 </capabilities>
10698 <parameters>
10699 <param id="info_ptr">
10700 <outptr><struct>jvmtiTimerInfo</struct></outptr>
10701 <description>
10702 On return, filled with information describing the time
10703 returned by <functionlink id="GetCurrentThreadCpuTime"/>.
10704 </description>
10705 </param>
10706 </parameters>
10707 <errors>
10708 </errors>
10709 </function>
10710
10711 <function id="GetCurrentThreadCpuTime" callbacksafe="safe" impl="innative notrace" phase="start" num="135">
10712 <synopsis>Get Current Thread CPU Time</synopsis>
10713 <description>
10714 Return the CPU time utilized by the current thread.
10715 <p/>
10716 Note that the <functionlink id="GetThreadCpuTime"/>
10717 function provides CPU time for any thread, including
10718 the current thread. <code>GetCurrentThreadCpuTime</code>
10719 exists to support platforms which cannot
10720 supply CPU time for threads other than the current
10721 thread or which have more accurate information for
10722 the current thread (see
10723 <functionlink id="GetCurrentThreadCpuTimerInfo"/> vs
10724 <functionlink id="GetThreadCpuTimerInfo"/>).
10725 On many platforms this call will be equivalent to:
10726 <example>
10727 GetThreadCpuTime(env, NULL, nanos_ptr)
10728 </example>
10729 </description>
10730 <origin>new</origin>
10731 <capabilities>
10732 <required id="can_get_current_thread_cpu_time">
10733 Can get current thread CPU time.
10734 <p/>
10735 If this capability is enabled after threads have started,
10736 the implementation may choose any time up
10737 to and including the time that the capability is enabled
10738 as the point where CPU time collection starts.
10739 <p/>
10740 This capability must be potentially available on any
10741 platform where
10742 <internallink id="jvmtiCapabilities.can_get_thread_cpu_time"><code>can_get_thread_cpu_time</code></internallink>
10743 is potentially available.
10744 </required>
10745 </capabilities>
10746 <parameters>
10747 <param id="nanos_ptr">
10748 <outptr><jlong/></outptr>
10749 <description>
10750 On return, points to the CPU time used by this thread
10751 in nanoseconds.
10752 This is an unsigned value. If tested or printed as a jlong (signed value)
10753 it may appear to be a negative number.
10754 </description>
10755 </param>
10756 </parameters>
10757 <errors>
10758 </errors>
10759 </function>
10760
10761 <function id="GetThreadCpuTimerInfo" num="136">
10762 <synopsis>Get Thread CPU Timer Information</synopsis>
10763 <description>
10764 Get information about the
10765 <functionlink id="GetThreadCpuTime"/> timer.
10766 The fields of the <datalink id="jvmtiTimerInfo"/> structure
10767 are filled in with details about the timer.
10768 This information is specific to the platform and the implementation of
10769 <functionlink id="GetThreadCpuTime"/> and thus
10770 does not vary by thread nor does it vary
10771 during a particular invocation of the VM.
10772 <p/>
10773 Note that the implementations of <functionlink id="GetCurrentThreadCpuTime"/>
10774 and <functionlink id="GetThreadCpuTime"/> may differ, and thus the values
10775 returned by <functionlink id="GetCurrentThreadCpuTimerInfo"/>
10776 and <code>GetThreadCpuTimerInfo</code>
10777 may differ -- see <functionlink id="GetCurrentThreadCpuTime"/> for more information.
10778 </description>
10779 <origin>new</origin>
10780 <capabilities>
10781 <required id="can_get_thread_cpu_time">
10782 Can get thread CPU time.
10783 </required>
10784 </capabilities>
10785 <parameters>
10786 <param id="info_ptr">
10787 <outptr><struct>jvmtiTimerInfo</struct></outptr>
10788 <description>
10789 On return, filled with information describing the time
10790 returned by <functionlink id="GetThreadCpuTime"/>.
10791 </description>
10792 </param>
10793 </parameters>
10794 <errors>
10795 </errors>
10796 </function>
10797
10798 <function id="GetThreadCpuTime" num="137">
10799 <synopsis>Get Thread CPU Time</synopsis>
10800 <description>
10801 Return the CPU time utilized by the specified thread.
10802 <p/>
10803 Get information about this timer with
10804 <functionlink id="GetThreadCpuTimerInfo"/>.
10805 </description>
10806 <origin>new</origin>
10807 <capabilities>
10808 <required id="can_get_thread_cpu_time">
10809 Can get thread CPU time.
10810 <p/>
10811 If this capability is enabled after threads have started,
10812 the implementation may choose any time up
10813 to and including the time that the capability is enabled
10814 as the point where CPU time collection starts.
10815 </required>
10816 </capabilities>
10817 <parameters>
10818 <param id="thread">
10819 <jthread null="current"/>
10820 <description>
10821 The thread to query.
10822 </description>
10823 </param>
10824 <param id="nanos_ptr">
10825 <outptr><jlong/></outptr>
10826 <description>
10827 On return, points to the CPU time used by the specified thread
10828 in nanoseconds.
10829 This is an unsigned value. If tested or printed as a jlong (signed value)
10830 it may appear to be a negative number.
10831 </description>
10832 </param>
10833 </parameters>
10834 <errors>
10835 </errors>
10836 </function>
10837
10838 <function id="GetTimerInfo" phase="any" callbacksafe="safe" num="138">
10839 <synopsis>Get Timer Information</synopsis>
10840 <description>
10841 Get information about the
10842 <functionlink id="GetTime"/> timer.
10843 The fields of the <datalink id="jvmtiTimerInfo"/> structure
10844 are filled in with details about the timer.
10845 This information will not change during a particular invocation of the VM.
10846 </description>
10847 <origin>new</origin>
10848 <capabilities>
10849 </capabilities>
10850 <parameters>
10851 <param id="info_ptr">
10852 <outptr><struct>jvmtiTimerInfo</struct></outptr>
10853 <description>
10854 On return, filled with information describing the time
10855 returned by <functionlink id="GetTime"/>.
10856 </description>
10857 </param>
10858 </parameters>
10859 <errors>
10860 </errors>
10861 </function>
10862
10863 <function id="GetTime" phase="any" callbacksafe="safe" num="139">
10864 <synopsis>Get Time</synopsis>
10865 <description>
10866 Return the current value of the system timer, in nanoseconds.
10867 <p/>
10868 The value returned represents nanoseconds since some fixed but
10869 arbitrary time (perhaps in the future, so values may be
10870 negative). This function provides nanosecond precision, but not
10871 necessarily nanosecond accuracy. No guarantees are made about
10872 how frequently values change.
10873 <p/>
10874 Get information about this timer with
10875 <functionlink id="GetTimerInfo"/>.
10876 </description>
10877 <origin>new</origin>
10878 <capabilities>
10879 </capabilities>
10880 <parameters>
10881 <param id="nanos_ptr">
10882 <outptr><jlong/></outptr>
10883 <description>
10884 On return, points to the time in nanoseconds.
10885 This is an unsigned value. If tested or printed as a jlong (signed value)
10886 it may appear to be a negative number.
10887 </description>
10888 </param>
10889 </parameters>
10890 <errors>
10891 </errors>
10892 </function>
10893
10894 <function id="GetAvailableProcessors" phase="any" num="144">
10895 <synopsis>Get Available Processors</synopsis>
10896 <description>
10897 Returns the number of processors available to the Java virtual machine.
10898 <p/>
10899 This value may change during a particular invocation of the virtual machine.
10900 Applications that are sensitive to the number of available processors should
10901 therefore occasionally poll this property.
10902 </description>
10903 <origin>new</origin>
10904 <capabilities>
10905 </capabilities>
10906 <parameters>
10907 <param id="processor_count_ptr">
10908 <outptr><jint/></outptr>
10909 <description>
10910 On return, points to the maximum number of processors available to the
10911 virtual machine; never smaller than one.
10912 </description>
10913 </param>
10914 </parameters>
10915 <errors>
10916 </errors>
10917 </function>
10918
10919 </category>
10920
10921
10922 <category id="classLoaderSearch" label="Class Loader Search">
10923
10924 <intro>
10925 These functions allow the agent to add to the locations that a class loader searches for a class.
10926 This is useful for installing instrumentation under the correct class loader.
10927 </intro>
10928
10929 <function id="AddToBootstrapClassLoaderSearch" jkernel="yes" phase="onload" num="149">
10930 <synopsis>Add To Bootstrap Class Loader Search</synopsis>
10931 <description>
10932 This function can be used to cause instrumentation classes to be defined by the
10933 bootstrap class loader. See <vmspec chapter="5.3.1"/>.
10934 After the bootstrap
10935 class loader unsuccessfully searches for a class, the specified platform-dependent
10936 search path <paramlink id="segment"/> will be searched as well. Only one segment may be specified in
10937 the <paramlink id="segment"/>. This function may be called multiple times to add multiple segments,
10938 the segments will be searched in the order that this function was called.
10939 <p/>
10940 In the <code>OnLoad</code> phase the function may be used to specify any platform-dependent
10941 search path segment to be searched after the bootstrap class loader unsuccessfully searches
10942 for a class. The segment is typically a directory or JAR file.
10943 <p/>
10944 In the live phase the <paramlink id="segment"/> may be used to specify any platform-dependent
10945 path to a <externallink id="jar/jar.html">
10946 JAR file</externallink>. The agent should take care that the JAR file does not
10947 contain any classes or resources other than those to be defined by the bootstrap
10948 class loader for the purposes of instrumentation.
10949 <p/>
10950 <vmspec/> specifies that a subsequent attempt to resolve a symbolic
10951 reference that the Java virtual machine has previously unsuccessfully attempted
10952 to resolve always fails with the same error that was thrown as a result of the
10953 initial resolution attempt. Consequently, if the JAR file contains an entry
10954 that corresponds to a class for which the Java virtual machine has
10955 unsuccessfully attempted to resolve a reference, then subsequent attempts to
10956 resolve that reference will fail with the same error as the initial attempt.
10957 </description>
10958 <origin>new</origin>
10959 <capabilities>
10960 </capabilities>
10961 <parameters>
10962 <param id="segment">
10963 <inbuf><char/></inbuf>
10964 <description>
10965 The platform-dependent search path segment, encoded as a
10966 <internallink id="mUTF">modified UTF-8</internallink> string.
10967 </description>
10968 </param>
10969 </parameters>
10970 <errors>
10971 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
10972 <paramlink id="segment"/> is an invalid path. In the live phase, anything other than an
10973 existing JAR file is an invalid path.
10974 </error>
10975 </errors>
10976 </function>
10977
10978 <function id="AddToSystemClassLoaderSearch" jkernel="yes" phase="onload" num="151" since="1.1">
10979 <synopsis>Add To System Class Loader Search</synopsis>
10980 <description>
10981 This function can be used to cause instrumentation classes to be
10982 defined by the system class loader. See <vmspec chapter="5.3.2"/>.
10983 After the class loader unsuccessfully searches for a class, the specified platform-dependent search
10984 path <paramlink id="segment"/> will be searched as well. Only one segment may be specified in the
10985 <paramlink id="segment"/>. This function may be called multiple times to add multiple segments, the
10986 segments will be searched in the order that this function was called.
10987 <p/>
10988 In the <code>OnLoad</code> phase the function may be used to specify any platform-dependent
10989 search path segment to be searched after the system class loader unsuccessfully searches
10990 for a class. The segment is typically a directory or JAR file.
10991 <p/>
10992 In the live phase the <paramlink id="segment"/> is a platform-dependent path to a
10993 <externallink id="jar/jar.html">JAR file</externallink> to be
10994 searched after the system class loader unsuccessfully searches for a class. The agent should
10995 take care that the JAR file does not contain any classes or resources other than those to be
10996 defined by the system class loader for the purposes of instrumentation.
10997 <p/>
10998 In the live phase the system class loader supports adding a JAR file to be searched if
10999 the system class loader implements a method name <code>appendToClassPathForInstrumentation</code>
11000 which takes a single parameter of type <code>java.lang.String</code>. The method is not required
11001 to have <code>public</code> access.
11002 <p/>
11003 <vmspec/> specifies that a subsequent attempt to resolve a symbolic
11004 reference that the Java virtual machine has previously unsuccessfully attempted
11005 to resolve always fails with the same error that was thrown as a result of the
11006 initial resolution attempt. Consequently, if the JAR file contains an entry
11007 that corresponds to a class for which the Java virtual machine has
11008 unsuccessfully attempted to resolve a reference, then subsequent attempts to
11009 resolve that reference will fail with the same error as the initial attempt.
11010 </description>
11011 <origin>new</origin>
11012 <capabilities>
11013 </capabilities>
11014 <parameters>
11015 <param id="segment">
11016 <inbuf><char/></inbuf>
11017 <description>
11018 The platform-dependent search path segment, encoded as a
11019 <internallink id="mUTF">modified UTF-8</internallink> string.
11020 </description>
11021 </param>
11022 </parameters>
11023 <errors>
11024 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
11025 <paramlink id="segment"/> is an invalid path. In the live phase, anything other than an
11026 existing JAR file is an invalid path.
11027 </error>
11028 <error id="JVMTI_ERROR_CLASS_LOADER_UNSUPPORTED">
11029 Operation not supported by the system class loader.
11030 </error>
11031 </errors>
11032 </function>
11033
11034 </category>
11035
11036
11037 <category id="props" label="System Properties">
11038
11039 <intro>
11040 These functions get and set system properties.
11041 </intro>
11042
11043 <function id="GetSystemProperties" phase="onload" num="130">
11044 <synopsis>Get System Properties</synopsis>
11045 <description>
11046 The list of VM system property keys which may be used with
11047 <functionlink id="GetSystemProperty"/> is returned.
11048 It is strongly recommended that virtual machines provide the
11049 following property keys:
11050 <ul>
11051 <li><code>java.vm.vendor</code></li>
11052 <li><code>java.vm.version</code></li>
11053 <li><code>java.vm.name</code></li>
11054 <li><code>java.vm.info</code></li>
11055 <li><code>java.library.path</code></li>
11056 <li><code>java.class.path</code></li>
11057 </ul>
11058 Provides access to system properties defined by and used
11059 by the VM.
11060 Properties set on the command-line are included.
11061 This allows getting and setting of these properties
11062 before the VM even begins executing bytecodes.
11063 Since this is a VM view of system properties, the set of available
11064 properties will usually be different than that
11065 in <code>java.lang.System.getProperties</code>.
11066 JNI method invocation may be used to access
11067 <code>java.lang.System.getProperties</code>.
11068 <p/>
11069 The set of properties may grow during execution.
11070 </description>
11071 <origin>new</origin>
11072 <capabilities>
11073 </capabilities>
11074 <parameters>
11075 <param id="count_ptr">
11076 <outptr><jint/></outptr>
11077 <description>
11078 On return, points to the number of property keys returned.
11079 </description>
11080 </param>
11081 <param id="property_ptr">
11082 <allocallocbuf outcount="count_ptr"><char/></allocallocbuf>
11083 <description>
11084 On return, points to an array of property keys, encoded as
11085 <internallink id="mUTF">modified UTF-8</internallink> strings.
11086 </description>
11087 </param>
11088 </parameters>
11089 <errors>
11090 </errors>
11091 </function>
11092
11093 <function id="GetSystemProperty" phase="onload" num="131">
11094 <synopsis>Get System Property</synopsis>
11095 <description>
11096 Return a VM system property value given the property key.
11097 <p/>
11098 The function <functionlink id="GetSystemProperties"/>
11099 returns the set of property keys which may be used.
11100 The properties which can be retrieved may grow during
11101 execution.
11102 <p/>
11103 Since this is a VM view of system properties, the values
11104 of properties may differ from that returned by
11105 <code>java.lang.System.getProperty(String)</code>.
11106 A typical VM might copy the values of the VM system
11107 properties into the <code>Properties</code> held by
11108 <code>java.lang.System</code> during the initialization
11109 of that class. Thereafter any changes to the VM system
11110 properties (with <functionlink id="SetSystemProperty"/>)
11111 or the <code>java.lang.System</code> system properties
11112 (with <code>java.lang.System.setProperty(String,String)</code>)
11113 would cause the values to diverge.
11114 JNI method invocation may be used to access
11115 <code>java.lang.System.getProperty(String)</code>.
11116 </description>
11117 <origin>new</origin>
11118 <capabilities>
11119 </capabilities>
11120 <parameters>
11121 <param id="property">
11122 <inbuf><char/></inbuf>
11123 <description>
11124 The key of the property to retrieve, encoded as a
11125 <internallink id="mUTF">modified UTF-8</internallink> string.
11126 </description>
11127 </param>
11128 <param id="value_ptr">
11129 <allocbuf><char/></allocbuf>
11130 <description>
11131 On return, points to the property value, encoded as a
11132 <internallink id="mUTF">modified UTF-8</internallink> string.
11133 </description>
11134 </param>
11135 </parameters>
11136 <errors>
11137 <error id="JVMTI_ERROR_NOT_AVAILABLE">
11138 This property is not available.
11139 Use <functionlink id="GetSystemProperties"/> to find available properties.
11140 </error>
11141 </errors>
11142 </function>
11143
11144 <function id="SetSystemProperty" phase="onloadOnly" num="132">
11145 <synopsis>Set System Property</synopsis>
11146 <description>
11147 Set a VM system property value.
11148 <p/>
11149 The function <functionlink id="GetSystemProperties"/>
11150 returns the set of property keys, some of these may be settable.
11151 See <functionlink id="GetSystemProperty"/>.
11152 </description>
11153 <origin>new</origin>
11154 <capabilities>
11155 </capabilities>
11156 <parameters>
11157 <param id="property">
11158 <inbuf><char/></inbuf>
11159 <description>
11160 The key of the property, encoded as a
11161 <internallink id="mUTF">modified UTF-8</internallink> string.
11162 </description>
11163 </param>
11164 <param id="value_ptr">
11165 <inbuf>
11166 <char/>
11167 <nullok>
11168 do not set the value, but return <errorlink id="JVMTI_ERROR_NOT_AVAILABLE"/>
11169 if the property is not writeable
11170 </nullok>
11171 </inbuf>
11172 <description>
11173 The property value to set, encoded as a
11174 <internallink id="mUTF">modified UTF-8</internallink> string.
11175 </description>
11176 </param>
11177 </parameters>
11178 <errors>
11179 <error id="JVMTI_ERROR_NOT_AVAILABLE">
11180 This property is not available or is not writeable.
11181 </error>
11182 </errors>
11183 </function>
11184
11185 </category>
11186
11187 <category id="general" label="General">
11188
11189 <intro>
11190 </intro>
11191
11192 <function id="GetPhase" jkernel="yes" phase="any" num="133">
11193 <synopsis>Get Phase</synopsis>
11194 <description>
11195 Return the current phase of VM execution.
11196 The phases proceed in sequence:
11197 <constants id="jvmtiPhase" label="Phases of execution" kind="enum">
11198 <constant id="JVMTI_PHASE_ONLOAD" num="1">
11199 <code>OnLoad</code> phase: while in the
11200 <internallink id="onload"><code>Agent_OnLoad</code></internallink>
11201 or, for statically linked agents, the <internallink id="onload">
11202 <code>Agent_OnLoad_<agent-lib-name>
11203 </code></internallink> function.
11204 </constant>
11205 <constant id="JVMTI_PHASE_PRIMORDIAL" num="2">
11206 Primordial phase: between return from <code>Agent_OnLoad</code>
11207 or <code>Agent_OnLoad_<agent-lib-name></code> and the
11208 <code>VMStart</code> event.
11209 </constant>
11210 <constant id="JVMTI_PHASE_START" num="6">
11211 Start phase: when the <eventlink id="VMStart"><code>VMStart</code></eventlink> event
11212 is sent and until the <code>VMInit</code> event is sent.
11213 </constant>
11214 <constant id="JVMTI_PHASE_LIVE" num="4">
11215 Live phase: when the <eventlink id="VMInit"><code>VMInit</code></eventlink> event is sent
11216 and until the <eventlink id="VMDeath"></eventlink> event returns.
11217 </constant>
11218 <constant id="JVMTI_PHASE_DEAD" num="8">
11219 Dead phase: after the <eventlink id="VMDeath"></eventlink> event returns or after
11220 start-up failure.
11221 </constant>
11222 </constants>
11223 In the case of start-up failure the VM will proceed directly to the dead
11224 phase skipping intermediate phases and neither a <code>VMInit</code> nor
11225 <code>VMDeath</code> event will be sent.
11226 <p/>
11227 Most <jvmti/> functions operate only in the live phase.
11228 The following functions operate in either the <code>OnLoad</code> or live phases:
11229 <functionphaselist phase="onload"/>
11230 The following functions operate in only the <code>OnLoad</code> phase:
11231 <functionphaselist phase="onloadOnly"/>
11232 The following functions operate in the start or live phases:
11233 <functionphaselist phase="start"/>
11234 The following functions operate in any phase:
11235 <functionphaselist phase="any"/>
11236 JNI functions (except the Invocation API) must only be used in the start or live phases.
11237 <p/>
11238 Most <jvmti/> events are sent only in the live phase.
11239 The following events operate in others phases:
11240 <eventphaselist phase="start"/>
11241 <eventphaselist phase="any"/>
11242 </description>
11243 <origin>new</origin>
11244 <capabilities>
11245 </capabilities>
11246 <parameters>
11247 <param id="phase_ptr">
11248 <outptr><enum>jvmtiPhase</enum></outptr>
11249 <description>
11250 On return, points to the phase.
11251 </description>
11252 </param>
11253 </parameters>
11254 <errors>
11255 </errors>
11256 </function>
11257
11258 <function id="DisposeEnvironment" jkernel="yes" phase="any" num="127">
11259 <synopsis>Dispose Environment</synopsis>
11260 <description>
11261 Shutdown a <jvmti/> connection created with JNI <code>GetEnv</code>
11262 (see <internallink id="environments"><jvmti/> Environments</internallink>).
11263 Dispose of any resources held by the environment.
11264 <issue>
11265 What resources are reclaimed? What is undone?
11266 Breakpoints,watchpoints removed?
11267 </issue>
11268 Threads suspended by this environment are not resumed by this call,
11269 this must be done explicitly by the agent.
11270 Memory allocated by this environment via calls to <jvmti/> functions
11271 is not released, this can be done explicitly by the agent
11272 by calling <functionlink id="Deallocate"/>.
11273 Raw monitors created by this environment are not destroyed,
11274 this can be done explicitly by the agent
11275 by calling <functionlink id="DestroyRawMonitor"/>.
11276 The state of threads waiting on raw monitors created by this environment
11277 are not affected.
11278 <p/>
11279 Any <functionlink id="SetNativeMethodPrefix">native method
11280 prefixes</functionlink> for this environment will be unset;
11281 the agent must remove any prefixed native methods before
11282 dispose is called.
11283 <p/>
11284 Any <internallink id="capability">capabilities</internallink>
11285 held by this environment are relinquished.
11286 <p/>
11287 Events enabled by this environment will no longer be sent, however
11288 event handlers currently running will continue to run. Caution must
11289 be exercised in the design of event handlers whose environment may
11290 be disposed and thus become invalid during their execution.
11291 <p/>
11292 This environment may not be used after this call.
11293 This call returns to the caller.
11294 </description>
11295 <origin>new</origin>
11296 <capabilities>
11297 </capabilities>
11298 <parameters>
11299 </parameters>
11300 <errors>
11301 </errors>
11302 </function>
11303
11304 <function id="SetEnvironmentLocalStorage" jkernel="yes" phase="any" callbacksafe="safe" impl="innative notrace" num="148">
11305 <synopsis>Set Environment Local Storage</synopsis>
11306 <description>
11307 The VM stores a pointer value associated with each environment.
11308 This pointer value is called <i>environment-local storage</i>.
11309 This value is <code>NULL</code> unless set with this function.
11310 Agents can allocate memory in which they store environment specific
11311 information. By setting environment-local storage it can then be
11312 accessed with
11313 <functionlink id="GetEnvironmentLocalStorage"></functionlink>.
11314 <p/>
11315 Called by the agent to set the value of the <jvmti/>
11316 environment-local storage. <jvmti/> supplies to the agent a pointer-size
11317 environment-local storage that can be used to record per-environment
11318 information.
11319 </description>
11320 <origin>new</origin>
11321 <capabilities>
11322 </capabilities>
11323 <parameters>
11324 <param id="data">
11325 <inbuf>
11326 <void/>
11327 <nullok>value is set to <code>NULL</code></nullok>
11328 </inbuf>
11329 <description>
11330 The value to be entered into the environment-local storage.
11331 </description>
11332 </param>
11333 </parameters>
11334 <errors>
11335 </errors>
11336 </function>
11337
11338 <function id="GetEnvironmentLocalStorage" jkernel="yes" phase="any" callbacksafe="safe" impl="innative notrace" num="147">
11339 <synopsis>Get Environment Local Storage</synopsis>
11340 <description>
11341 Called by the agent to get the value of the <jvmti/> environment-local
11342 storage.
11343 </description>
11344 <origin>new</origin>
11345 <capabilities>
11346 </capabilities>
11347 <parameters>
11348 <param id="data_ptr">
11349 <agentbuf><void/></agentbuf>
11350 <description>
11351 Pointer through which the value of the environment local
11352 storage is returned.
11353 If environment-local storage has not been set with
11354 <functionlink id="SetEnvironmentLocalStorage"></functionlink> returned
11355 pointer is <code>NULL</code>.
11356 </description>
11357 </param>
11358 </parameters>
11359 <errors>
11360 </errors>
11361 </function>
11362
11363 <function id="GetVersionNumber" jkernel="yes" phase="any" num="88">
11364 <synopsis>Get Version Number</synopsis>
11365 <description>
11366 Return the <jvmti/> version via <code>version_ptr</code>.
11367 The return value is the version identifier.
11368 The version identifier includes major, minor and micro
11369 version as well as the interface type.
11370 <constants id="jvmtiVersionInterfaceTypes" label="Version Interface Types" kind="bits">
11371 <constant id="JVMTI_VERSION_INTERFACE_JNI" num="0x00000000">
11372 Value of <code>JVMTI_VERSION_MASK_INTERFACE_TYPE</code> for JNI.
11373 </constant>
11374 <constant id="JVMTI_VERSION_INTERFACE_JVMTI" num="0x30000000">
11375 Value of <code>JVMTI_VERSION_MASK_INTERFACE_TYPE</code> for <jvmti/>.
11376 </constant>
11377 </constants>
11378 <constants id="jvmtiVersionMasks" label="Version Masks" kind="bits">
11379 <constant id="JVMTI_VERSION_MASK_INTERFACE_TYPE" num="0x70000000">
11380 Mask to extract interface type.
11381 The value of the version returned by this function masked with
11382 <code>JVMTI_VERSION_MASK_INTERFACE_TYPE</code> is always
11383 <code>JVMTI_VERSION_INTERFACE_JVMTI</code>
11384 since this is a <jvmti/> function.
11385 </constant>
11386 <constant id="JVMTI_VERSION_MASK_MAJOR" num="0x0FFF0000">
11387 Mask to extract major version number.
11388 </constant>
11389 <constant id="JVMTI_VERSION_MASK_MINOR" num="0x0000FF00">
11390 Mask to extract minor version number.
11391 </constant>
11392 <constant id="JVMTI_VERSION_MASK_MICRO" num="0x000000FF">
11393 Mask to extract micro version number.
11394 </constant>
11395 </constants>
11396 <constants id="jvmtiVersionShifts" label="Version Shifts" kind="bits">
11397 <constant id="JVMTI_VERSION_SHIFT_MAJOR" num="16">
11398 Shift to extract major version number.
11399 </constant>
11400 <constant id="JVMTI_VERSION_SHIFT_MINOR" num="8">
11401 Shift to extract minor version number.
11402 </constant>
11403 <constant id="JVMTI_VERSION_SHIFT_MICRO" num="0">
11404 Shift to extract micro version number.
11405 </constant>
11406 </constants>
11407 </description>
11408 <origin>jvmdi</origin>
11409 <capabilities>
11410 </capabilities>
11411 <parameters>
11412 <param id="version_ptr">
11413 <outptr><jint/></outptr>
11414 <description>
11415 On return, points to the <jvmti/> version.
11416 </description>
11417 </param>
11418 </parameters>
11419 <errors>
11420 </errors>
11421 </function>
11422
11423
11424 <function id="GetErrorName" phase="any" num="128">
11425 <synopsis>Get Error Name</synopsis>
11426 <description>
11427 Return the symbolic name for an
11428 <internallink id="ErrorSection">error code</internallink>.
11429 <p/>
11430 For example
11431 <code>GetErrorName(env, JVMTI_ERROR_NONE, &err_name)</code>
11432 would return in <code>err_name</code> the string
11433 <code>"JVMTI_ERROR_NONE"</code>.
11434 </description>
11435 <origin>new</origin>
11436 <capabilities>
11437 </capabilities>
11438 <parameters>
11439 <param id="error">
11440 <enum>jvmtiError</enum>
11441 <description>
11442 The error code.
11443 </description>
11444 </param>
11445 <param id="name_ptr">
11446 <allocbuf><char/></allocbuf>
11447 <description>
11448 On return, points to the error name.
11449 The name is encoded as a
11450 <internallink id="mUTF">modified UTF-8</internallink> string,
11451 but is restricted to the ASCII subset.
11452 </description>
11453 </param>
11454 </parameters>
11455 <errors>
11456 </errors>
11457 </function>
11458
11459 <function id="SetVerboseFlag" phase="any" num="150">
11460 <synopsis>Set Verbose Flag</synopsis>
11461 <description>
11462 <constants id="jvmtiVerboseFlag" label="Verbose Flag Enumeration" kind="enum">
11463 <constant id="JVMTI_VERBOSE_OTHER" num="0">
11464 Verbose output other than the below.
11465 </constant>
11466 <constant id="JVMTI_VERBOSE_GC" num="1">
11467 Verbose garbage collector output, like that specified with <code>-verbose:gc</code>.
11468 </constant>
11469 <constant id="JVMTI_VERBOSE_CLASS" num="2">
11470 Verbose class loading output, like that specified with <code>-verbose:class</code>.
11471 </constant>
11472 <constant id="JVMTI_VERBOSE_JNI" num="4">
11473 Verbose JNI output, like that specified with <code>-verbose:jni</code>.
11474 </constant>
11475 </constants>
11476 Control verbose output.
11477 This is the output which typically is sent to <code>stderr</code>.
11478 </description>
11479 <origin>new</origin>
11480 <capabilities>
11481 </capabilities>
11482 <parameters>
11483 <param id="flag">
11484 <enum>jvmtiVerboseFlag</enum>
11485 <description>
11486 Which verbose flag to set.
11487 </description>
11488 </param>
11489 <param id="value">
11490 <jboolean/>
11491 <description>
11492 New value of the flag.
11493 </description>
11494 </param>
11495 </parameters>
11496 <errors>
11497 </errors>
11498 </function>
11499
11500
11501 <function id="GetJLocationFormat" phase="any" num="129">
11502 <synopsis>Get JLocation Format</synopsis>
11503 <description>
11504 Although the greatest functionality is achieved with location information
11505 referencing the virtual machine bytecode index, the definition of
11506 <code>jlocation</code> has intentionally been left unconstrained to allow VM
11507 implementations that do not have this information.
11508 <p/>
11509 This function describes the representation of <code>jlocation</code> used in this VM.
11510 If the returned format is <datalink id="JVMTI_JLOCATION_JVMBCI"></datalink>,
11511 <code>jlocation</code>s can
11512 be used as in indices into the array returned by
11513 <functionlink id="GetBytecodes"></functionlink>.
11514 <constants id="jvmtiJlocationFormat" label="JLocation Format Enumeration" kind="enum">
11515 <constant id="JVMTI_JLOCATION_JVMBCI" num="1">
11516 <code>jlocation</code> values represent virtual machine
11517 bytecode indices--that is, offsets into the
11518 virtual machine code for a method.
11519 </constant>
11520 <constant id="JVMTI_JLOCATION_MACHINEPC" num="2">
11521 <code>jlocation</code> values represent native machine
11522 program counter values.
11523 </constant>
11524 <constant id="JVMTI_JLOCATION_OTHER" num="0">
11525 <code>jlocation</code> values have some other representation.
11526 </constant>
11527 </constants>
11528 </description>
11529 <origin>new</origin>
11530 <capabilities>
11531 </capabilities>
11532 <parameters>
11533 <param id="format_ptr">
11534 <outptr><enum>jvmtiJlocationFormat</enum></outptr>
11535 <description>
11536 On return, points to the format identifier for <code>jlocation</code> values.
11537 </description>
11538 </param>
11539 </parameters>
11540 <errors>
11541 </errors>
11542 </function>
11543
11544 </category>
11545
11546 </functionsection>
11547
11548 <errorsection label="Error Reference">
11549 <intro>
11550 Every <jvmti/> function returns a <b><code>jvmtiError</code></b> error code.
11551 <p/>
11552 It is the responsibility of the agent to call <jvmti/> functions with
11553 valid parameters and in the proper context (calling thread is attached,
11554 phase is correct, etc.).
11555 Detecting some error conditions may be difficult, inefficient, or
11556 impossible for an implementation.
11557 The errors listed in
11558 <internallink id="reqerrors">Function Specific Required Errors</internallink>
11559 must be detected by the implementation.
11560 All other errors represent the recommended response to the error
11561 condition.
11562 </intro>
11563
11564 <errorcategory id="universal-error" label="Universal Errors">
11565 <intro>
11566 The following errors may be returned by any function
11567 </intro>
11568
11569 <errorid id="JVMTI_ERROR_NONE" num="0">
11570 No error has occurred. This is the error code that is returned
11571 on successful completion of the function.
11572 </errorid>
11573 <errorid id="JVMTI_ERROR_NULL_POINTER" num="100">
11574 Pointer is unexpectedly <code>NULL</code>.
11575 </errorid>
11576 <errorid id="JVMTI_ERROR_OUT_OF_MEMORY" num="110">
11577 The function attempted to allocate memory and no more memory was
11578 available for allocation.
11579 </errorid>
11580 <errorid id="JVMTI_ERROR_ACCESS_DENIED" num="111">
11581 The desired functionality has not been enabled in this virtual machine.
11582 </errorid>
11583 <errorid id="JVMTI_ERROR_UNATTACHED_THREAD" num="115">
11584 The thread being used to call this function is not attached
11585 to the virtual machine. Calls must be made from attached threads.
11586 See <code>AttachCurrentThread</code> in the JNI invocation API.
11587 </errorid>
11588 <errorid id="JVMTI_ERROR_INVALID_ENVIRONMENT" num="116">
11589 The <jvmti/> environment provided is no longer connected or is
11590 not an environment.
11591 </errorid>
11592 <errorid id="JVMTI_ERROR_WRONG_PHASE" num="112">
11593 The desired functionality is not available in the current
11594 <functionlink id="GetPhase">phase</functionlink>.
11595 Always returned if the virtual machine has completed running.
11596 </errorid>
11597 <errorid id="JVMTI_ERROR_INTERNAL" num="113">
11598 An unexpected internal error has occurred.
11599 </errorid>
11600 </errorcategory>
11601
11602 <errorcategory id="reqerrors" label="Function Specific Required Errors">
11603 <intro>
11604 The following errors are returned by some <jvmti/> functions and must
11605 be returned by the implementation when the condition occurs.
11606 </intro>
11607
11608 <errorid id="JVMTI_ERROR_INVALID_PRIORITY" num="12">
11609 Invalid priority.
11610 </errorid>
11611 <errorid id="JVMTI_ERROR_THREAD_NOT_SUSPENDED" num="13">
11612 Thread was not suspended.
11613 </errorid>
11614 <errorid id="JVMTI_ERROR_THREAD_SUSPENDED" num="14">
11615 Thread already suspended.
11616 </errorid>
11617 <errorid id="JVMTI_ERROR_THREAD_NOT_ALIVE" num="15">
11618 This operation requires the thread to be alive--that is,
11619 it must be started and not yet have died.
11620 </errorid>
11621 <errorid id="JVMTI_ERROR_CLASS_NOT_PREPARED" num="22">
11622 The class has been loaded but not yet prepared.
11623 </errorid>
11624 <errorid id="JVMTI_ERROR_NO_MORE_FRAMES" num="31">
11625 There are no Java programming language or JNI stack frames at the specified depth.
11626 </errorid>
11627 <errorid id="JVMTI_ERROR_OPAQUE_FRAME" num="32">
11628 Information about the frame is not available (e.g. for native frames).
11629 </errorid>
11630 <errorid id="JVMTI_ERROR_DUPLICATE" num="40">
11631 Item already set.
11632 </errorid>
11633 <errorid id="JVMTI_ERROR_NOT_FOUND" num="41">
11634 Desired element (e.g. field or breakpoint) not found
11635 </errorid>
11636 <errorid id="JVMTI_ERROR_NOT_MONITOR_OWNER" num="51">
11637 This thread doesn't own the raw monitor.
11638 </errorid>
11639 <errorid id="JVMTI_ERROR_INTERRUPT" num="52">
11640 The call has been interrupted before completion.
11641 </errorid>
11642 <errorid id="JVMTI_ERROR_UNMODIFIABLE_CLASS" num="79">
11643 The class cannot be modified.
11644 </errorid>
11645 <errorid id="JVMTI_ERROR_UNMODIFIABLE_MODULE" num="80">
11646 The module cannot be modified.
11647 </errorid>
11648 <errorid id="JVMTI_ERROR_NOT_AVAILABLE" num="98">
11649 The functionality is not available in this virtual machine.
11650 </errorid>
11651 <errorid id="JVMTI_ERROR_ABSENT_INFORMATION" num="101">
11652 The requested information is not available.
11653 </errorid>
11654 <errorid id="JVMTI_ERROR_INVALID_EVENT_TYPE" num="102">
11655 The specified event type ID is not recognized.
11656 </errorid>
11657 <errorid id="JVMTI_ERROR_NATIVE_METHOD" num="104">
11658 The requested information is not available for native method.
11659 </errorid>
11660 <errorid id="JVMTI_ERROR_CLASS_LOADER_UNSUPPORTED" num="106">
11661 The class loader does not support this operation.
11662 </errorid>
11663 </errorcategory>
11664
11665 <errorcategory id="function-specific-errors" label="Function Specific Agent Errors">
11666 <intro>
11667 The following errors are returned by some <jvmti/> functions.
11668 They are returned in the event of invalid parameters passed by the
11669 agent or usage in an invalid context.
11670 An implementation is not required to detect these errors.
11671 </intro>
11672
11673 <errorid id="JVMTI_ERROR_INVALID_THREAD" num="10">
11674 The passed thread is not a valid thread.
11675 </errorid>
11676 <errorid id="JVMTI_ERROR_INVALID_FIELDID" num="25">
11677 Invalid field.
11678 </errorid>
11679 <errorid id="JVMTI_ERROR_INVALID_MODULE" num="26">
11680 Invalid module.
11681 </errorid>
11682 <errorid id="JVMTI_ERROR_INVALID_METHODID" num="23">
11683 Invalid method.
11684 </errorid>
11685 <errorid id="JVMTI_ERROR_INVALID_LOCATION" num="24">
11686 Invalid location.
11687 </errorid>
11688 <errorid id="JVMTI_ERROR_INVALID_OBJECT" num="20">
11689 Invalid object.
11690 </errorid>
11691 <errorid id="JVMTI_ERROR_INVALID_CLASS" num="21">
11692 Invalid class.
11693 </errorid>
11694 <errorid id="JVMTI_ERROR_TYPE_MISMATCH" num="34">
11695 The variable is not an appropriate type for the function used.
11696 </errorid>
11697 <errorid id="JVMTI_ERROR_INVALID_SLOT" num="35">
11698 Invalid slot.
11699 </errorid>
11700 <errorid id="JVMTI_ERROR_MUST_POSSESS_CAPABILITY" num="99">
11701 The capability being used is false in this environment.
11702 </errorid>
11703 <errorid id="JVMTI_ERROR_INVALID_THREAD_GROUP" num="11">
11704 Thread group invalid.
11705 </errorid>
11706 <errorid id="JVMTI_ERROR_INVALID_MONITOR" num="50">
11707 Invalid raw monitor.
11708 </errorid>
11709 <errorid id="JVMTI_ERROR_ILLEGAL_ARGUMENT" num="103">
11710 Illegal argument.
11711 </errorid>
11712 <errorid id="JVMTI_ERROR_INVALID_TYPESTATE" num="65">
11713 The state of the thread has been modified, and is now inconsistent.
11714 </errorid>
11715 <errorid id="JVMTI_ERROR_UNSUPPORTED_VERSION" num="68">
11716 A new class file has a version number not supported by this VM.
11717 </errorid>
11718 <errorid id="JVMTI_ERROR_INVALID_CLASS_FORMAT" num="60">
11719 A new class file is malformed (the VM would return a <code>ClassFormatError</code>).
11720 </errorid>
11721 <errorid id="JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION" num="61">
11722 The new class file definitions would lead to a circular
11723 definition (the VM would return a <code>ClassCircularityError</code>).
11724 </errorid>
11725 <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED" num="63">
11726 A new class file would require adding a method.
11727 </errorid>
11728 <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED" num="64">
11729 A new class version changes a field.
11730 </errorid>
11731 <errorid id="JVMTI_ERROR_FAILS_VERIFICATION" num="62">
11732 The class bytes fail verification.
11733 </errorid>
11734 <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED" num="66">
11735 A direct superclass is different for the new class
11736 version, or the set of directly implemented
11737 interfaces is different.
11738 </errorid>
11739 <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED" num="67">
11740 A new class version does not declare a method
11741 declared in the old class version.
11742 </errorid>
11743 <errorid id="JVMTI_ERROR_NAMES_DONT_MATCH" num="69">
11744 The class name defined in the new class file is
11745 different from the name in the old class object.
11746 </errorid>
11747 <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED" num="70">
11748 A new class version has different modifiers.
11749 </errorid>
11750 <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED" num="71">
11751 A method in the new class version has different modifiers
11752 than its counterpart in the old class version.
11753 </errorid>
11754 <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED" num="72">
11755 A new class version has unsupported differences in class attributes.
11756 </errorid>
11757 </errorcategory>
11758 </errorsection>
11759
11760 <eventsection label="Events">
11761 <intro label="Handling Events" id="eventIntro">
11762 Agents can be informed of many events that occur in application
11763 programs.
11764 <p/>
11765 To handle events, designate a set of callback functions with
11766 <functionlink id="SetEventCallbacks"></functionlink>.
11767 For each event the corresponding callback function will be
11768 called.
11769 Arguments to the callback function provide additional
11770 information about the event.
11771 <p/>
11772 The callback function is usually called from within an application
11773 thread. The <jvmti/> implementation does not
11774 queue events in any way. This means
11775 that event callback functions must be written
11776 carefully. Here are some general guidelines. See
11777 the individual event descriptions for further
11778 suggestions.
11779 <p/>
11780 <ul>
11781 <li>Any exception thrown during the execution of an event callback can
11782 overwrite any current pending exception in the current application thread.
11783 Care must be taken to preserve a pending exception
11784 when an event callback makes a JNI call that might generate an exception.
11785 </li>
11786 <li>Event callback functions must be re-entrant. The <jvmti/> implementation does
11787 not queue events. If an agent needs to process events one at a time, it
11788 can use a raw monitor inside the
11789 event callback functions to serialize event processing.
11790 </li>
11791 <li>Event callback functions that execute JNI's FindClass function to load
11792 classes need to note that FindClass locates the class loader associated
11793 with the current native method. For the purposes of class loading, an
11794 event callback that includes a JNI environment as a parameter to the
11795 callback will treated as if it is a native call, where the native method
11796 is in the class of the event thread's current frame.
11797 </li>
11798 </ul>
11799 <p/>
11800 Some <jvmti/> events identify objects with JNI references.
11801 All references
11802 in <jvmti/> events are JNI local references and will become invalid
11803 after the event callback returns.
11804 Unless stated otherwise, memory referenced by pointers sent in event
11805 callbacks may not be referenced after the event callback returns.
11806 <p/>
11807 Except where stated otherwise, events are delivered on the thread
11808 that caused the event.
11809 Events are sent at the time they occur.
11810 The specification for each event includes the set of
11811 <functionlink id="GetPhase">phases</functionlink> in which it can be sent;
11812 if an event triggering activity occurs during another phase, no event
11813 is sent.
11814 <p/>
11815 A thread that generates an event does not change its execution status
11816 (for example, the event does not cause the thread to be suspended).
11817 If an agent wishes the event to result in suspension, then the agent
11818 is responsible for explicitly suspending the thread with
11819 <functionlink id="SuspendThread"></functionlink>.
11820 <p/>
11821 If an event is enabled in multiple environments, the event will be sent
11822 to each agent in the order that the environments were created.
11823 </intro>
11824
11825 <intro label="Enabling Events" id="enablingevents">
11826 All events are initially disabled. In order to receive any
11827 event:
11828 <ul>
11829 <li>
11830 If the event requires a capability, that capability must
11831 be added with
11832 <functionlink id="AddCapabilities"></functionlink>.
11833 </li>
11834 <li>
11835 A callback for the event must be set with
11836 <functionlink id="SetEventCallbacks"></functionlink>.
11837 </li>
11838 <li>
11839 The event must be enabled with
11840 <functionlink id="SetEventNotificationMode"></functionlink>.
11841 </li>
11842 </ul>
11843 </intro>
11844
11845 <intro label="Multiple Co-located Events" id="eventorder">
11846 In many situations it is possible for multiple events to occur
11847 at the same location in one thread. When this happens, all the events
11848 are reported through the event callbacks in the order specified in this section.
11849 <p/>
11850 If the current location is at the entry point of a method, the
11851 <eventlink id="MethodEntry"></eventlink> event is reported before
11852 any other event at the current location in the same thread.
11853 <p/>
11854 If an exception catch has been detected at the current location,
11855 either because it is the beginning of a catch clause or a native method
11856 that cleared a pending exception has returned, the
11857 <code>exceptionCatch</code> event is reported before
11858 any other event at the current location in the same thread.
11859 <p/>
11860 If a <code>singleStep</code> event or
11861 <code>breakpoint</code> event is triggered at the
11862 current location, the event is defined to occur
11863 immediately before the code at the current location is executed.
11864 These events are reported before any events which are triggered
11865 by the execution of code at the current location in the same
11866 thread (specifically:
11867 <code>exception</code>,
11868 <code>fieldAccess</code>, and
11869 <code>fieldModification</code>).
11870 If both a step and breakpoint event are triggered for the same thread and
11871 location, the step event is reported before the breakpoint event.
11872 <p/>
11873 If the current location is the exit point of a method (that is, the last
11874 location before returning to the caller), the
11875 <eventlink id="MethodExit"></eventlink> event and
11876 the <eventlink id="FramePop"></eventlink> event (if requested)
11877 are reported after all other events at the current location in the same
11878 thread. There is no specified ordering of these two events
11879 with respect to each other.
11880 <p/>
11881 Co-located events can be triggered during the processing of some other
11882 event by the agent at the same location in the same thread.
11883 If such an event, of type <i>y</i>, is triggered during the processing of
11884 an event of type <i>x</i>, and if <i>x</i>
11885 precedes <i>y</i> in the ordering specified above, the co-located event
11886 <i>y</i> is reported for the current thread and location. If <i>x</i> does not precede
11887 <i>y</i>, <i>y</i> is not reported for the current thread and location.
11888 For example, if a breakpoint is set at the current location
11889 during the processing of <eventlink id="SingleStep"></eventlink>,
11890 that breakpoint will be reported before the thread moves off the current
11891 location.
11892 <p/>The following events are never considered to be co-located with
11893 other events.
11894 <ul>
11895 <li><eventlink id="VMStart"></eventlink></li>
11896 <li><eventlink id="VMInit"></eventlink></li>
11897 <li><eventlink id="VMDeath"></eventlink></li>
11898 <li><eventlink id="ThreadStart"></eventlink></li>
11899 <li><eventlink id="ThreadEnd"></eventlink></li>
11900 <li><eventlink id="ClassLoad"></eventlink></li>
11901 <li><eventlink id="ClassPrepare"></eventlink></li>
11902 </ul>
11903 </intro>
11904
11905 <intro label="Event Callbacks" id="jvmtiEventCallbacks">
11906 The event callback structure below is used to specify the handler function
11907 for events. It is set with the
11908 <functionlink id="SetEventCallbacks"></functionlink> function.
11909 </intro>
11910
11911 <event label="Single Step"
11912 id="SingleStep" const="JVMTI_EVENT_SINGLE_STEP" filtered="thread" num="60">
11913 <description>
11914 Single step events allow the agent to trace thread execution
11915 at the finest granularity allowed by the VM. A single step event is
11916 generated whenever a thread reaches a new location.
11917 Typically, single step events represent the completion of one VM
11918 instruction as defined in <vmspec/>. However, some implementations
11919 may define locations differently. In any case the
11920 <code>method</code> and <code>location</code>
11921 parameters uniquely identify the current location and allow
11922 the mapping to source file and line number when that information is
11923 available.
11924 <p/>
11925 No single step events are generated from within native methods.
11926 </description>
11927 <origin>jvmdi</origin>
11928 <capabilities>
11929 <required id="can_generate_single_step_events"></required>
11930 </capabilities>
11931 <parameters>
11932 <param id="jni_env">
11933 <outptr>
11934 <struct>JNIEnv</struct>
11935 </outptr>
11936 <description>
11937 The JNI environment of the event (current) thread
11938 </description>
11939 </param>
11940 <param id="thread">
11941 <jthread/>
11942 <description>
11943 Thread about to execution a new instruction
11944 </description>
11945 </param>
11946 <param id="klass">
11947 <jclass method="method"/>
11948 <description>
11949 Class of the method about to execute a new instruction
11950 </description>
11951 </param>
11952 <param id="method">
11953 <jmethodID class="klass"/>
11954 <description>
11955 Method about to execute a new instruction
11956 </description>
11957 </param>
11958 <param id="location">
11959 <jlocation/>
11960 <description>
11961 Location of the new instruction
11962 </description>
11963 </param>
11964 </parameters>
11965 </event>
11966
11967 <event label="Breakpoint"
11968 id="Breakpoint" const="JVMTI_EVENT_BREAKPOINT" filtered="thread" num="62">
11969 <description>
11970 Breakpoint events are generated whenever a thread reaches a location
11971 designated as a breakpoint with <functionlink id="SetBreakpoint"></functionlink>.
11972 The <code>method</code> and <code>location</code>
11973 parameters uniquely identify the current location and allow
11974 the mapping to source file and line number when that information is
11975 available.
11976 </description>
11977 <origin>jvmdi</origin>
11978 <capabilities>
11979 <required id="can_generate_breakpoint_events"></required>
11980 </capabilities>
11981 <parameters>
11982 <param id="jni_env">
11983 <outptr>
11984 <struct>JNIEnv</struct>
11985 </outptr>
11986 <description>
11987 The JNI environment of the event (current) thread.
11988 </description>
11989 </param>
11990 <param id="thread">
11991 <jthread/>
11992 <description>
11993 Thread that hit the breakpoint
11994 </description>
11995 </param>
11996 <param id="klass">
11997 <jclass method="method"/>
11998 <description>
11999 Class of the method that hit the breakpoint
12000 </description>
12001 </param>
12002 <param id="method">
12003 <jmethodID class="klass"/>
12004 <description>
12005 Method that hit the breakpoint
12006 </description>
12007 </param>
12008 <param id="location">
12009 <jlocation/>
12010 <description>
12011 location of the breakpoint
12012 </description>
12013 </param>
12014 </parameters>
12015 </event>
12016
12017 <event label="Field Access"
12018 id="FieldAccess" const="JVMTI_EVENT_FIELD_ACCESS" filtered="thread" num="63">
12019 <description>
12020 Field access events are generated whenever a thread accesses
12021 a field that was designated as a watchpoint
12022 with <functionlink id="SetFieldAccessWatch"></functionlink>.
12023 The <code>method</code> and <code>location</code>
12024 parameters uniquely identify the current location and allow
12025 the mapping to source file and line number when that information is
12026 available.
12027 </description>
12028 <origin>jvmdi</origin>
12029 <capabilities>
12030 <required id="can_generate_field_access_events"></required>
12031 </capabilities>
12032 <parameters>
12033 <param id="jni_env">
12034 <outptr>
12035 <struct>JNIEnv</struct>
12036 </outptr>
12037 <description>
12038 The JNI environment of the event (current) thread
12039 </description>
12040 </param>
12041 <param id="thread">
12042 <jthread/>
12043 <description>
12044 Thread accessing the field
12045 </description>
12046 </param>
12047 <param id="klass">
12048 <jclass method="method"/>
12049 <description>
12050 Class of the method where the access is occurring
12051 </description>
12052 </param>
12053 <param id="method">
12054 <jmethodID class="klass"/>
12055 <description>
12056 Method where the access is occurring
12057 </description>
12058 </param>
12059 <param id="location">
12060 <jlocation/>
12061 <description>
12062 Location where the access is occurring
12063 </description>
12064 </param>
12065 <param id="field_klass">
12066 <jclass field="field"/>
12067 <description>
12068 Class of the field being accessed
12069 </description>
12070 </param>
12071 <param id="object">
12072 <jobject/>
12073 <description>
12074 Object with the field being accessed if the field is an
12075 instance field; <code>NULL</code> otherwise
12076 </description>
12077 </param>
12078 <param id="field">
12079 <jfieldID class="field_klass"/>
12080 <description>
12081 Field being accessed
12082 </description>
12083 </param>
12084 </parameters>
12085 </event>
12086
12087 <event label="Field Modification"
12088 id="FieldModification" const="JVMTI_EVENT_FIELD_MODIFICATION" filtered="thread" num="64">
12089 <description>
12090 Field modification events are generated whenever a thread modifies
12091 a field that was designated as a watchpoint
12092 with <functionlink id="SetFieldModificationWatch"></functionlink>.
12093 The <code>method</code> and <code>location</code>
12094 parameters uniquely identify the current location and allow
12095 the mapping to source file and line number when that information is
12096 available.
12097 </description>
12098 <origin>jvmdi</origin>
12099 <capabilities>
12100 <required id="can_generate_field_modification_events"></required>
12101 </capabilities>
12102 <parameters>
12103 <param id="jni_env">
12104 <outptr>
12105 <struct>JNIEnv</struct>
12106 </outptr>
12107 <description>
12108 The JNI environment of the event (current) thread
12109 </description>
12110 </param>
12111 <param id="thread">
12112 <jthread/>
12113 <description>
12114 Thread modifying the field
12115 </description>
12116 </param>
12117 <param id="klass">
12118 <jclass method="method"/>
12119 <description>
12120 Class of the method where the modification is occurring
12121 </description>
12122 </param>
12123 <param id="method">
12124 <jmethodID class="klass"/>
12125 <description>
12126 Method where the modification is occurring
12127 </description>
12128 </param>
12129 <param id="location">
12130 <jlocation/>
12131 <description>
12132 Location where the modification is occurring
12133 </description>
12134 </param>
12135 <param id="field_klass">
12136 <jclass field="field"/>
12137 <description>
12138 Class of the field being modified
12139 </description>
12140 </param>
12141 <param id="object">
12142 <jobject/>
12143 <description>
12144 Object with the field being modified if the field is an
12145 instance field; <code>NULL</code> otherwise
12146 </description>
12147 </param>
12148 <param id="field">
12149 <jfieldID class="field_klass"/>
12150 <description>
12151 Field being modified
12152 </description>
12153 </param>
12154 <param id="signature_type">
12155 <char/>
12156 <description>
12157 Signature type of the new value
12158 </description>
12159 </param>
12160 <param id="new_value">
12161 <jvalue/>
12162 <description>
12163 The new value
12164 </description>
12165 </param>
12166 </parameters>
12167 </event>
12168
12169 <event label="Frame Pop"
12170 id="FramePop" const="JVMTI_EVENT_FRAME_POP" filtered="thread" num="61">
12171 <description>
12172 Frame pop events are generated upon exit from a single method
12173 in a single frame as specified
12174 in a call to <functionlink id="NotifyFramePop"></functionlink>.
12175 This is true whether termination is caused by
12176 executing its return instruction
12177 or by throwing an exception to its caller
12178 (see <paramlink id="was_popped_by_exception"></paramlink>).
12179 However, frame pops caused by the <functionlink id="PopFrame"/>
12180 function are not reported.
12181 <p/>
12182 The location reported by <functionlink id="GetFrameLocation"></functionlink>
12183 identifies the executable location in the returning method,
12184 immediately prior to the return.
12185 </description>
12186 <origin>jvmdi</origin>
12187 <capabilities>
12188 <required id="can_generate_frame_pop_events"></required>
12189 </capabilities>
12190 <parameters>
12191 <param id="jni_env">
12192 <outptr>
12193 <struct>JNIEnv</struct>
12194 </outptr>
12195 <description>
12196 The JNI environment of the event (current) thread
12197 </description>
12198 </param>
12199 <param id="thread">
12200 <jthread/>
12201 <description>
12202 Thread that is popping the frame
12203 </description>
12204 </param>
12205 <param id="klass">
12206 <jclass method="method"/>
12207 <description>
12208 Class of the method being popped
12209 </description>
12210 </param>
12211 <param id="method">
12212 <jmethodID class="klass"/>
12213 <description>
12214 Method being popped
12215 </description>
12216 </param>
12217 <param id="was_popped_by_exception">
12218 <jboolean/>
12219 <description>
12220 True if frame was popped by a thrown exception.
12221 False if method exited through its return instruction.
12222 </description>
12223 </param>
12224 </parameters>
12225 </event>
12226
12227 <event label="Method Entry"
12228 id="MethodEntry" const="JVMTI_EVENT_METHOD_ENTRY" filtered="thread" num="65">
12229 <description>
12230 Method entry events are generated upon entry of Java
12231 programming language methods (including native methods).
12232 <p/>
12233 The location reported by <functionlink id="GetFrameLocation"></functionlink>
12234 identifies the initial executable location in
12235 the method.
12236 <p/>
12237 Enabling method
12238 entry or exit events will significantly degrade performance on many platforms and is thus
12239 not advised for performance critical usage (such as profiling).
12240 <internallink id="bci">Bytecode instrumentation</internallink> should be
12241 used in these cases.
12242 </description>
12243 <origin>jvmdi</origin>
12244 <capabilities>
12245 <required id="can_generate_method_entry_events"></required>
12246 </capabilities>
12247 <parameters>
12248 <param id="jni_env">
12249 <outptr>
12250 <struct>JNIEnv</struct>
12251 </outptr>
12252 <description>
12253 The JNI environment of the event (current) thread
12254 </description>
12255 </param>
12256 <param id="thread">
12257 <jthread/>
12258 <description>
12259 Thread entering the method
12260 </description>
12261 </param>
12262 <param id="klass">
12263 <jclass method="method"/>
12264 <description>
12265 Class of the method being entered
12266 </description>
12267 </param>
12268 <param id="method">
12269 <jmethodID class="klass"/>
12270 <description>
12271 Method being entered
12272 </description>
12273 </param>
12274 </parameters>
12275 </event>
12276
12277 <event label="Method Exit"
12278 id="MethodExit" const="JVMTI_EVENT_METHOD_EXIT" filtered="thread" num="66">
12279 <description>
12280 Method exit events are generated upon exit from Java
12281 programming language methods (including native methods).
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 <p/>
12287 The <code>method</code> field uniquely identifies the
12288 method being entered or exited. The <code>frame</code> field provides
12289 access to the stack frame for the method.
12290 <p/>
12291 The location reported by <functionlink id="GetFrameLocation"></functionlink>
12292 identifies the executable location in the returning method
12293 immediately prior to the return.
12294 <p/>
12295 Enabling method
12296 entry or exit events will significantly degrade performance on many platforms and is thus
12297 not advised for performance critical usage (such as profiling).
12298 <internallink id="bci">Bytecode instrumentation</internallink> should be
12299 used in these cases.
12300 </description>
12301 <origin>jvmdi</origin>
12302 <capabilities>
12303 <required id="can_generate_method_exit_events"></required>
12304 </capabilities>
12305 <parameters>
12306 <param id="jni_env">
12307 <outptr>
12308 <struct>JNIEnv</struct>
12309 </outptr>
12310 <description>
12311 The JNI environment of the event (current) thread
12312 </description>
12313 </param>
12314 <param id="thread">
12315 <jthread/>
12316 <description>
12317 Thread exiting the method
12318 </description>
12319 </param>
12320 <param id="klass">
12321 <jclass method="method"/>
12322 <description>
12323 Class of the method being exited
12324 </description>
12325 </param>
12326 <param id="method">
12327 <jmethodID class="klass"/>
12328 <description>
12329 Method being exited
12330 </description>
12331 </param>
12332 <param id="was_popped_by_exception">
12333 <jboolean/>
12334 <description>
12335 True if frame was popped by a thrown exception.
12336 False if method exited through its return instruction.
12337 </description>
12338 </param>
12339 <param id="return_value">
12340 <jvalue/>
12341 <description>
12342 The return value of the method being exited.
12343 Undefined and should not be used if
12344 <paramlink id="was_popped_by_exception"></paramlink>
12345 is true.
12346 </description>
12347 </param>
12348 </parameters>
12349 </event>
12350
12351 <event label="Native Method Bind" phase="any"
12352 id="NativeMethodBind" const="JVMTI_EVENT_NATIVE_METHOD_BIND" num="67">
12353 <description>
12354 A Native Method Bind event is sent when a VM binds a
12355 Java programming language native method
12356 to the address of a function that implements the native method.
12357 This will occur when the native method is called for the first time
12358 and also occurs when the JNI function <code>RegisterNatives</code> is called.
12359 This event allows the bind to be redirected to an agent-specified
12360 proxy function.
12361 This event is not sent when the native method is unbound.
12362 Typically, this proxy function will need to be specific to a
12363 particular method or, to handle the general case, automatically
12364 generated assembly code, since after instrumentation code is
12365 executed the function at the original binding
12366 address will usually be invoked.
12367 The original binding can be restored or the redirection changed
12368 by use of the JNI function <code>RegisterNatives</code>.
12369 Some events may be sent during the primordial phase, JNI and
12370 most of <jvmti/> cannot be used at this time but the method and
12371 address can be saved for use later.
12372 </description>
12373 <origin>new</origin>
12374 <capabilities>
12375 <required id="can_generate_native_method_bind_events"></required>
12376 </capabilities>
12377 <parameters>
12378 <param id="jni_env">
12379 <outptr>
12380 <struct>JNIEnv</struct>
12381 </outptr>
12382 <description>
12383 The JNI environment of the event (current) thread
12384 Will be <code>NULL</code> if sent during the primordial
12385 <functionlink id="GetPhase">phase</functionlink>.
12386 </description>
12387 </param>
12388 <param id="thread">
12389 <jthread/>
12390 <description>
12391 Thread requesting the bind
12392 </description>
12393 </param>
12394 <param id="klass">
12395 <jclass method="method"/>
12396 <description>
12397 Class of the method being bound
12398 </description>
12399 </param>
12400 <param id="method">
12401 <jmethodID class="klass"/>
12402 <description>
12403 Native method being bound
12404 </description>
12405 </param>
12406 <param id="address">
12407 <outptr><void/></outptr>
12408 <description>
12409 The address the VM is about to bind to--that is, the
12410 address of the implementation of the native method
12411 </description>
12412 </param>
12413 <param id="new_address_ptr">
12414 <agentbuf><void/></agentbuf>
12415 <description>
12416 if the referenced address is changed (that is, if
12417 <code>*new_address_ptr</code> is set), the binding
12418 will instead be made to the supplied address.
12419 </description>
12420 </param>
12421 </parameters>
12422 </event>
12423
12424 <event label="Exception"
12425 id="Exception" const="JVMTI_EVENT_EXCEPTION" filtered="thread" num="58">
12426 <description>
12427 Exception events are generated whenever an exception is first detected
12428 in a Java programming language method.
12429 Where "exception" means any <code>java.lang.Throwable</code>.
12430 The exception may have been thrown by a Java programming language or native
12431 method, but in the case of native methods, the event is not generated
12432 until the exception is first seen by a Java programming language method. If an exception is
12433 set and cleared in a native method (and thus is never visible to Java programming language code),
12434 no exception event is generated.
12435 <p/>
12436 The <code>method</code> and <code>location</code>
12437 parameters uniquely identify the current location
12438 (where the exception was detected) and allow
12439 the mapping to source file and line number when that information is
12440 available. The <code>exception</code> field identifies the thrown
12441 exception object. The <code>catch_method</code>
12442 and <code>catch_location</code> identify the location of the catch clause,
12443 if any, that handles the thrown exception. If there is no such catch clause,
12444 each field is set to 0. There is no guarantee that the thread will ever
12445 reach this catch clause. If there are native methods on the call stack
12446 between the throw location and the catch clause, the exception may
12447 be reset by one of those native methods.
12448 Similarly, exceptions that are reported as uncaught (<code>catch_klass</code>
12449 et al. set to 0) may in fact be caught by native code.
12450 Agents can check for these occurrences by monitoring
12451 <eventlink id="ExceptionCatch"></eventlink> events.
12452 Note that finally clauses are implemented as catch and re-throw. Therefore they
12453 will be reported in the catch location.
12454 </description>
12455 <origin>jvmdi</origin>
12456 <capabilities>
12457 <required id="can_generate_exception_events"></required>
12458 </capabilities>
12459 <parameters>
12460 <param id="jni_env">
12461 <outptr>
12462 <struct>JNIEnv</struct>
12463 </outptr>
12464 <description>
12465 The JNI environment of the event (current) thread
12466 </description>
12467 </param>
12468 <param id="thread">
12469 <jthread/>
12470 <description>
12471 Thread generating the exception
12472 </description>
12473 </param>
12474 <param id="klass">
12475 <jclass method="method"/>
12476 <description>
12477 Class generating the exception
12478 </description>
12479 </param>
12480 <param id="method">
12481 <jmethodID class="klass"/>
12482 <description>
12483 Method generating the exception
12484 </description>
12485 </param>
12486 <param id="location">
12487 <jlocation/>
12488 <description>
12489 Location where exception occurred
12490 </description>
12491 </param>
12492 <param id="exception">
12493 <jobject/>
12494 <description>
12495 The exception being thrown
12496 </description>
12497 </param>
12498 <param id="catch_klass">
12499 <jclass method="catch_method"/>
12500 <description>
12501 Class that will catch the exception, or <code>NULL</code> if no known catch
12502 </description>
12503 </param>
12504 <param id="catch_method">
12505 <jmethodID class="catch_klass"/>
12506 <description>
12507 Method that will catch the exception, or <code>NULL</code> if no known catch
12508 </description>
12509 </param>
12510 <param id="catch_location">
12511 <jlocation/>
12512 <description>
12513 location which will catch the exception or zero if no known catch
12514 </description>
12515 </param>
12516 </parameters>
12517 </event>
12518
12519 <event label="Exception Catch"
12520 id="ExceptionCatch" const="JVMTI_EVENT_EXCEPTION_CATCH" filtered="thread" num="59">
12521 <description>
12522 Exception catch events are generated whenever a thrown exception is caught.
12523 Where "exception" means any <code>java.lang.Throwable</code>.
12524 If the exception is caught in a Java programming language method, the event is generated
12525 when the catch clause is reached. If the exception is caught in a native
12526 method, the event is generated as soon as control is returned to a Java programming language
12527 method. Exception catch events are generated for any exception for which
12528 a throw was detected in a Java programming language method.
12529 Note that finally clauses are implemented as catch and re-throw. Therefore they
12530 will generate exception catch events.
12531 <p/>
12532 The <code>method</code> and <code>location</code>
12533 parameters uniquely identify the current location
12534 and allow the mapping to source file and line number when that information is
12535 available. For exceptions caught in a Java programming language method, the
12536 <code>exception</code> object identifies the exception object. Exceptions
12537 caught in native methods are not necessarily available by the time the
12538 exception catch is reported, so the <code>exception</code> field is set
12539 to <code>NULL</code>.
12540 </description>
12541 <origin>jvmdi</origin>
12542 <capabilities>
12543 <required id="can_generate_exception_events"></required>
12544 </capabilities>
12545 <parameters>
12546 <param id="jni_env">
12547 <outptr>
12548 <struct>JNIEnv</struct>
12549 </outptr>
12550 <description>
12551 The JNI environment of the event (current) thread
12552 </description>
12553 </param>
12554 <param id="thread">
12555 <jthread/>
12556 <description>
12557 Thread catching the exception
12558 </description>
12559 </param>
12560 <param id="klass">
12561 <jclass method="method"/>
12562 <description>
12563 Class catching the exception
12564 </description>
12565 </param>
12566 <param id="method">
12567 <jmethodID class="klass"/>
12568 <description>
12569 Method catching the exception
12570 </description>
12571 </param>
12572 <param id="location">
12573 <jlocation/>
12574 <description>
12575 Location where exception is being caught
12576 </description>
12577 </param>
12578 <param id="exception">
12579 <jobject/>
12580 <description>
12581 Exception being caught
12582 </description>
12583 </param>
12584 </parameters>
12585 </event>
12586
12587 <event label="Thread Start"
12588 id="ThreadStart" const="JVMTI_EVENT_THREAD_START" num="52" phase="start">
12589 <description>
12590 Thread start events are generated by a new thread before its initial
12591 method executes.
12592 <p/>
12593 A thread may be listed in the array returned by
12594 <functionlink id="GetAllThreads"></functionlink>
12595 before its thread start event is generated.
12596 It is possible for other events to be generated
12597 on a thread before its thread start event.
12598 <p/>
12599 The event is sent on the newly started <paramlink id="thread"></paramlink>.
12600 </description>
12601 <origin>jvmdi</origin>
12602 <capabilities>
12603 </capabilities>
12604 <parameters>
12605 <param id="jni_env">
12606 <outptr>
12607 <struct>JNIEnv</struct>
12608 </outptr>
12609 <description>
12610 The JNI environment of the event (current) thread.
12611 </description>
12612 </param>
12613 <param id="thread">
12614 <jthread/>
12615 <description>
12616 Thread starting
12617 </description>
12618 </param>
12619 </parameters>
12620 </event>
12621
12622 <event label="Thread End"
12623 id="ThreadEnd" const="JVMTI_EVENT_THREAD_END" filtered="thread" num="53" phase="start">
12624 <description>
12625 Thread end events are generated by a terminating thread
12626 after its initial method has finished execution.
12627 <p/>
12628 A thread may be listed in the array returned by
12629 <functionlink id="GetAllThreads"></functionlink>
12630 after its thread end event is generated.
12631 No events are generated on a thread
12632 after its thread end event.
12633 <p/>
12634 The event is sent on the dying <paramlink id="thread"></paramlink>.
12635 </description>
12636 <origin>jvmdi</origin>
12637 <capabilities>
12638 </capabilities>
12639 <parameters>
12640 <param id="jni_env">
12641 <outptr>
12642 <struct>JNIEnv</struct>
12643 </outptr>
12644 <description>
12645 The JNI environment of the event (current) thread.
12646 </description>
12647 </param>
12648 <param id="thread">
12649 <jthread/>
12650 <description>
12651 Thread ending
12652 </description>
12653 </param>
12654 </parameters>
12655 </event>
12656
12657 <event label="Class Load"
12658 id="ClassLoad" const="JVMTI_EVENT_CLASS_LOAD" filtered="thread" phase="start" num="55">
12659 <description>
12660 A class load event is generated when a class is first loaded. The order
12661 of class load events generated by a particular thread are guaranteed
12662 to match the order of class loading within that thread.
12663 Array class creation does not generate a class load event.
12664 The creation of a primitive class (for example, java.lang.Integer.TYPE)
12665 does not generate a class load event.
12666 <p/>
12667 This event is sent at an early stage in loading the class. As
12668 a result the class should be used carefully. Note, for example,
12669 that methods and fields are not yet loaded, so queries for methods,
12670 fields, subclasses, and so on will not give correct results.
12671 See "Loading of Classes and Interfaces" in the <i>Java Language
12672 Specification</i>. For most
12673 purposes the <eventlink id="ClassPrepare"></eventlink> event will
12674 be more useful.
12675 </description>
12676 <origin>jvmdi</origin>
12677 <capabilities>
12678 </capabilities>
12679 <parameters>
12680 <param id="jni_env">
12681 <outptr>
12682 <struct>JNIEnv</struct>
12683 </outptr>
12684 <description>
12685 The JNI environment of the event (current) thread
12686 </description>
12687 </param>
12688 <param id="thread">
12689 <jthread/>
12690 <description>
12691 Thread loading the class
12692 </description>
12693 </param>
12694 <param id="klass">
12695 <jclass/>
12696 <description>
12697 Class being loaded
12698 </description>
12699 </param>
12700 </parameters>
12701 </event>
12702
12703 <elide>
12704 <event label="Class Unload"
12705 id="ClassUnload" const="JVMTI_EVENT_CLASS_UNLOAD" num="57">
12706 <description>
12707 A class unload event is generated when the class is about to be unloaded.
12708 Class unload events take place during garbage collection and must be
12709 handled extremely carefully. The garbage collector holds many locks
12710 and has suspended all other threads, so the event handler cannot depend
12711 on the ability to acquire any locks. The class unload event handler should
12712 do as little as possible, perhaps by queuing information to be processed
12713 later. In particular, the <code>jclass</code> should be used only in
12714 the JNI function <code>isSameObject</code> or in the following <jvmti/> functions:
12715 <ul>
12716 <li><functionlink id="GetClassSignature"></functionlink></li>
12717 <li><functionlink id="GetSourceFileName"></functionlink></li>
12718 <li><functionlink id="IsInterface"></functionlink></li>
12719 <li><functionlink id="IsArrayClass"></functionlink></li>
12720 </ul>
12721 </description>
12722 <origin>jvmdi</origin>
12723 <capabilities>
12724 </capabilities>
12725 <parameters>
12726 <param id="jni_env">
12727 <outptr>
12728 <struct>JNIEnv</struct>
12729 </outptr>
12730 <description>
12731 The JNI environment of the event (current) thread
12732 </description>
12733 </param>
12734 <param id="thread">
12735 <jthread/>
12736 <description>
12737 Thread generating the class unload
12738 </description>
12739 </param>
12740 <param id="klass">
12741 <jclass/>
12742 <description>
12743 Class being unloaded
12744 </description>
12745 </param>
12746 </parameters>
12747 </event>
12748 </elide>
12749
12750 <event label="Class Prepare"
12751 id="ClassPrepare" const="JVMTI_EVENT_CLASS_PREPARE" filtered="thread" phase="start" num="56">
12752 <description>
12753 A class prepare event is generated when class preparation is complete.
12754 At this point, class fields, methods, and implemented interfaces are
12755 available, and no code from the class has been executed. Since array
12756 classes never have fields or methods, class prepare events are not
12757 generated for them. Class prepare events are not generated for
12758 primitive classes (for example, <code>java.lang.Integer.TYPE</code>).
12759 </description>
12760 <origin>jvmdi</origin>
12761 <capabilities>
12762 </capabilities>
12763 <parameters>
12764 <param id="jni_env">
12765 <outptr>
12766 <struct>JNIEnv</struct>
12767 </outptr>
12768 <description>
12769 The JNI environment of the event (current) thread
12770 </description>
12771 </param>
12772 <param id="thread">
12773 <jthread/>
12774 <description>
12775 Thread generating the class prepare
12776 </description>
12777 </param>
12778 <param id="klass">
12779 <jclass/>
12780 <description>
12781 Class being prepared
12782 </description>
12783 </param>
12784 </parameters>
12785 </event>
12786
12787 <event label="Class File Load Hook" phase="any"
12788 id="ClassFileLoadHook" const="JVMTI_EVENT_CLASS_FILE_LOAD_HOOK" num="54">
12789 <description>
12790 This event is sent when the VM obtains class file data,
12791 but before it constructs
12792 the in-memory representation for that class.
12793 This event is also sent when the class is being modified by the
12794 <functionlink id="RetransformClasses"/> function or
12795 the <functionlink id="RedefineClasses"/> function,
12796 called in any <jvmti/> environment.
12797 The agent can instrument
12798 the existing class file data sent by the VM to include profiling/debugging hooks.
12799 See the description of
12800 <internallink id="bci">bytecode instrumentation</internallink>
12801 for usage information.
12802 <p/>
12803 When the capabilities
12804 <internallink id="jvmtiCapabilities.can_generate_early_class_hook_events">
12805 <code>can_generate_early_class_hook_events</code></internallink> and
12806 <internallink id="jvmtiCapabilities.can_generate_all_class_hook_events">
12807 <code>can_generate_all_class_hook_events</code></internallink>
12808 are enabled then this event may be sent in the primordial phase.
12809 Otherwise, this event may be sent before the VM is initialized (the start
12810 <functionlink id="GetPhase">phase</functionlink>).
12811 Some classes might not be compatible
12812 with the function (eg. ROMized classes or implementation defined classes) and this event will
12813 not be generated for these classes.
12814 <p/>
12815 The agent must allocate the space for the modified
12816 class file data buffer
12817 using the memory allocation function
12818 <functionlink id="Allocate"></functionlink> because the
12819 VM is responsible for freeing the new class file data buffer
12820 using <functionlink id="Deallocate"></functionlink>.
12821 <p/>
12822 If the agent wishes to modify the class file, it must set
12823 <code>new_class_data</code> to point
12824 to the newly instrumented class file data buffer and set
12825 <code>new_class_data_len</code> to the length of that
12826 buffer before returning
12827 from this call. If no modification is desired, the agent simply
12828 does not set <code>new_class_data</code>. If multiple agents
12829 have enabled this event the results are chained. That is, if
12830 <code>new_class_data</code> has been set, it becomes the
12831 <code>class_data</code> for the next agent.
12832 <p/>
12833 When handling a class load in the live phase, then the
12834 <functionlink id="GetNamedModule"></functionlink>
12835 function can be used to map class loader and a package name to a module.
12836 When a class is being redefined or retransformed then
12837 <code>class_being_redefined</code> is non <code>NULL</code> and so
12838 the JNI <code>GetModule</code> function can also be used
12839 to obtain the Module.
12840 <p/>
12841 The order that this event is sent to each environment differs
12842 from other events.
12843 This event is sent to environments in the following order:
12844 <ul>
12845 <li><fieldlink id="can_retransform_classes"
12846 struct="jvmtiCapabilities">retransformation
12847 incapable</fieldlink>
12848 environments, in the
12849 order in which they were created
12850 </li>
12851 <li><fieldlink id="can_retransform_classes"
12852 struct="jvmtiCapabilities">retransformation
12853 capable</fieldlink>
12854 environments, in the
12855 order in which they were created
12856 </li>
12857 </ul>
12858 When triggered by <functionlink id="RetransformClasses"/>,
12859 this event is sent only to <fieldlink id="can_retransform_classes"
12860 struct="jvmtiCapabilities">retransformation
12861 capable</fieldlink>
12862 environments.
12863 </description>
12864 <origin>jvmpi</origin>
12865 <capabilities>
12866 <capability id="can_generate_all_class_hook_events"></capability>
12867 <capability id="can_generate_early_class_hook_events"></capability>
12868 </capabilities>
12869 <parameters>
12870 <param id="jni_env">
12871 <outptr>
12872 <struct>JNIEnv</struct>
12873 </outptr>
12874 <description>
12875 The JNI environment of the event (current) thread.
12876 </description>
12877 </param>
12878 <param id="class_being_redefined">
12879 <jclass/>
12880 <description>
12881 The class being
12882 <functionlink id="RedefineClasses">redefined</functionlink> or
12883 <functionlink id="RetransformClasses">retransformed</functionlink>.
12884 <code>NULL</code> if sent by class load.
12885 </description>
12886 </param>
12887 <param id="loader">
12888 <jobject/>
12889 <description>
12890 The class loader loading the class.
12891 <code>NULL</code> if the bootstrap class loader.
12892 </description>
12893 </param>
12894 <param id="name">
12895 <vmbuf><char/></vmbuf>
12896 <description>
12897 Name of class being loaded as a VM internal qualified name
12898 (for example, "java/util/List"), encoded as a
12899 <internallink id="mUTF">modified UTF-8</internallink> string.
12900 Note: if the class is defined with a <code>NULL</code> name or
12901 without a name specified, <code>name</code> will be <code>NULL</code>.
12902 </description>
12903 </param>
12904 <param id="protection_domain">
12905 <jobject/>
12906 <description>
12907 The <code>ProtectionDomain</code> of the class.
12908 </description>
12909 </param>
12910 <param id="class_data_len">
12911 <jint/>
12912 <description>
12913 Length of current class file data buffer.
12914 </description>
12915 </param>
12916 <param id="class_data">
12917 <vmbuf><uchar/></vmbuf>
12918 <description>
12919 Pointer to the current class file data buffer.
12920 </description>
12921 </param>
12922 <param id="new_class_data_len">
12923 <outptr><jint/></outptr>
12924 <description>
12925 Pointer to the length of the new class file data buffer.
12926 </description>
12927 </param>
12928 <param id="new_class_data">
12929 <agentbuf incount="new_class_data_len"><uchar/></agentbuf>
12930 <description>
12931 Pointer to the pointer to the instrumented class file data buffer.
12932 </description>
12933 </param>
12934 </parameters>
12935 </event>
12936
12937 <event label="VM Start Event"
12938 id="VMStart" const="JVMTI_EVENT_VM_START" num="57" phase="start">
12939 <description>
12940 The VM start event signals the start of the VM.
12941 At this time JNI is live but the VM is not yet fully initialized.
12942 Once this event is generated, the agent is free to call any JNI function.
12943 This event signals the beginning of the start phase,
12944 <jvmti/> functions permitted in the start phase may be called.
12945 <p/>
12946 The timing of this event may depend on whether the agent has added the
12947 <internallink id="jvmtiCapabilities.can_generate_early_vmstart">
12948 <code>can_generate_early_vmstart</code></internallink> capability or not.
12949 If the capability has been added then the VM posts the event as early
12950 as possible. The VM is capable of executing bytecode but it may not have
12951 initialized to the point where it can load classes in modules other than
12952 <code>java.base</code>, or even arbitrary classes in <code>java.base</code>.
12953 Agents that do load-time instrumentation in this
12954 phase must take great care when instrumenting code that potentially
12955 executes in this phase. Extreme care should also be taken with JNI
12956 <code>FindClass</code> as it may not be possible to load classes and attempts
12957 to do so may result in unpredictable behavior, maybe even stability issues
12958 on some VM implementations.
12959 If the capability has not been added then the VM delays posting this
12960 event until it is capable of loading classes in modules other than
12961 <code>java.base</code> or the VM has completed its initialization.
12962 Agents that create more than one JVM TI environment, where the
12963 capability is added to some but not all environments, may observe the
12964 start phase beginning earlier in the JVM TI environments that possess
12965 the capabilty.
12966 <p/>
12967 In the case of VM start-up failure, this event will not be sent.
12968 </description>
12969 <origin>jvmdi</origin>
12970 <capabilities>
12971 </capabilities>
12972 <parameters>
12973 <param id="jni_env">
12974 <outptr>
12975 <struct>JNIEnv</struct>
12976 </outptr>
12977 <description>
12978 The JNI environment of the event (current) thread.
12979 </description>
12980 </param>
12981 </parameters>
12982 </event>
12983
12984 <event label="VM Initialization Event"
12985 id="VMInit" const="JVMTI_EVENT_VM_INIT" num="50">
12986 <description>
12987 The VM initialization event signals the completion of VM initialization. Once
12988 this event is generated, the agent is free to call any JNI or <jvmti/>
12989 function. The VM initialization event can be preceded by or can be concurrent
12990 with other events, but
12991 the preceding events should be handled carefully, if at all, because the
12992 VM has not completed its initialization. The thread start event for the
12993 main application thread is guaranteed not to occur until after the
12994 handler for the VM initialization event returns.
12995 <p/>
12996 In the case of VM start-up failure, this event will not be sent.
12997 </description>
12998 <origin>jvmdi</origin>
12999 <capabilities>
13000 </capabilities>
13001 <parameters>
13002 <param id="jni_env">
13003 <outptr>
13004 <struct>JNIEnv</struct>
13005 </outptr>
13006 <description>
13007 The JNI environment of the event (current) thread.
13008 </description>
13009 </param>
13010 <param id="thread">
13011 <jthread/>
13012 <description>
13013 The initial thread
13014 </description>
13015 </param>
13016 </parameters>
13017 </event>
13018
13019 <event label="VM Death Event"
13020 id="VMDeath" const="JVMTI_EVENT_VM_DEATH" num="51">
13021 <description>
13022 The VM death event notifies the agent of the termination of the VM.
13023 No events will occur after the VMDeath event.
13024 <p/>
13025 In the case of VM start-up failure, this event will not be sent.
13026 Note that <internallink id="onunload">Agent_OnUnload</internallink>
13027 will still be called in these cases.
13028 </description>
13029 <origin>jvmdi</origin>
13030 <capabilities>
13031 </capabilities>
13032 <parameters>
13033 <param id="jni_env">
13034 <outptr>
13035 <struct>JNIEnv</struct>
13036 </outptr>
13037 <description>
13038 The JNI environment of the event (current) thread
13039 </description>
13040 </param>
13041 </parameters>
13042 </event>
13043
13044 <event label="Compiled Method Load" phase="start"
13045 id="CompiledMethodLoad" const="JVMTI_EVENT_COMPILED_METHOD_LOAD" num="68">
13046 <description>
13047 Sent when a method is compiled and loaded into memory by the VM.
13048 If it is unloaded, the <eventlink id="CompiledMethodUnload"/> event is sent.
13049 If it is moved, the <eventlink id="CompiledMethodUnload"/> event is sent,
13050 followed by a new <code>CompiledMethodLoad</code> event.
13051 Note that a single method may have multiple compiled forms, and that
13052 this event will be sent for each form.
13053 Note also that several methods may be inlined into a single
13054 address range, and that this event will be sent for each method.
13055 <p/>
13056 These events can be sent after their initial occurrence with
13057 <functionlink id="GenerateEvents"></functionlink>.
13058 </description>
13059 <origin>jvmpi</origin>
13060 <typedef id="jvmtiAddrLocationMap" label="Native address to location entry">
13061 <field id="start_address">
13062 <vmbuf><void/></vmbuf>
13063 <description>
13064 Starting native address of code corresponding to a location
13065 </description>
13066 </field>
13067 <field id="location">
13068 <jlocation/>
13069 <description>
13070 Corresponding location. See
13071 <functionlink id="GetJLocationFormat"></functionlink>
13072 for the meaning of location.
13073 </description>
13074 </field>
13075 </typedef>
13076 <capabilities>
13077 <required id="can_generate_compiled_method_load_events"></required>
13078 </capabilities>
13079 <parameters>
13080 <param id="klass">
13081 <jclass method="method"/>
13082 <description>
13083 Class of the method being compiled and loaded
13084 </description>
13085 </param>
13086 <param id="method">
13087 <jmethodID class="klass"/>
13088 <description>
13089 Method being compiled and loaded
13090 </description>
13091 </param>
13092 <param id="code_size">
13093 <jint/>
13094 <description>
13095 Size of compiled code
13096 </description>
13097 </param>
13098 <param id="code_addr">
13099 <vmbuf><void/></vmbuf>
13100 <description>
13101 Address where compiled method code is loaded
13102 </description>
13103 </param>
13104 <param id="map_length">
13105 <jint/>
13106 <description>
13107 Number of <typelink id="jvmtiAddrLocationMap"></typelink>
13108 entries in the address map.
13109 Zero if mapping information cannot be supplied.
13110 </description>
13111 </param>
13112 <param id="map">
13113 <vmbuf><struct>jvmtiAddrLocationMap</struct></vmbuf>
13114 <description>
13115 Map from native addresses to location.
13116 The native address range of each entry is from
13117 <fieldlink id="start_address" struct="jvmtiAddrLocationMap"></fieldlink>
13118 to <code>start_address-1</code> of the next entry.
13119 <code>NULL</code> if mapping information cannot be supplied.
13120 </description>
13121 </param>
13122 <param id="compile_info">
13123 <vmbuf><void/></vmbuf>
13124 <description>
13125 VM-specific compilation information.
13126 The referenced compile information is managed by the VM
13127 and must not depend on the agent for collection.
13128 A VM implementation defines the content and lifetime
13129 of the information.
13130 </description>
13131 </param>
13132 </parameters>
13133 </event>
13134
13135 <event label="Compiled Method Unload" phase="start"
13136 id="CompiledMethodUnload" const="JVMTI_EVENT_COMPILED_METHOD_UNLOAD" num="69">
13137 <description>
13138 Sent when a compiled method is unloaded from memory.
13139 This event might not be sent on the thread which performed the unload.
13140 This event may be sent sometime after the unload occurs, but
13141 will be sent before the memory is reused
13142 by a newly generated compiled method. This event may be sent after
13143 the class is unloaded.
13144 </description>
13145 <origin>jvmpi</origin>
13146 <capabilities>
13147 <required id="can_generate_compiled_method_load_events"></required>
13148 </capabilities>
13149 <parameters>
13150 <param id="klass">
13151 <jclass method="method"/>
13152 <description>
13153 Class of the compiled method being unloaded.
13154 </description>
13155 </param>
13156 <param id="method">
13157 <jmethodID class="klass"/>
13158 <description>
13159 Compiled method being unloaded.
13160 For identification of the compiled method only -- the class
13161 may be unloaded and therefore the method should not be used
13162 as an argument to further JNI or <jvmti/> functions.
13163 </description>
13164 </param>
13165 <param id="code_addr">
13166 <vmbuf><void/></vmbuf>
13167 <description>
13168 Address where compiled method code was loaded.
13169 For identification of the compiled method only --
13170 the space may have been reclaimed.
13171 </description>
13172 </param>
13173 </parameters>
13174 </event>
13175
13176 <event label="Dynamic Code Generated" phase="any"
13177 id="DynamicCodeGenerated" const="JVMTI_EVENT_DYNAMIC_CODE_GENERATED" num="70">
13178 <description>
13179 Sent when a component of the virtual machine is generated dynamically.
13180 This does not correspond to Java programming language code that is
13181 compiled--see <eventlink id="CompiledMethodLoad"></eventlink>.
13182 This is for native code--for example, an interpreter that is generated
13183 differently depending on command-line options.
13184 <p/>
13185 Note that this event has no controlling capability.
13186 If a VM cannot generate these events, it simply does not send any.
13187 <p/>
13188 These events can be sent after their initial occurrence with
13189 <functionlink id="GenerateEvents"></functionlink>.
13190 </description>
13191 <origin>jvmpi</origin>
13192 <capabilities>
13193 </capabilities>
13194 <parameters>
13195 <param id="name">
13196 <vmbuf><char/></vmbuf>
13197 <description>
13198 Name of the code, encoded as a
13199 <internallink id="mUTF">modified UTF-8</internallink> string.
13200 Intended for display to an end-user.
13201 The name might not be unique.
13202 </description>
13203 </param>
13204 <param id="address">
13205 <vmbuf><void/></vmbuf>
13206 <description>
13207 Native address of the code
13208 </description>
13209 </param>
13210 <param id="length">
13211 <jint/>
13212 <description>
13213 Length in bytes of the code
13214 </description>
13215 </param>
13216 </parameters>
13217 </event>
13218
13219 <event label="Data Dump Request"
13220 id="DataDumpRequest" const="JVMTI_EVENT_DATA_DUMP_REQUEST" num="71">
13221 <description>
13222 Sent by the VM to request the agent to dump its data. This
13223 is just a hint and the agent need not react to this event.
13224 This is useful for processing command-line signals from users. For
13225 example, in the Java 2 SDK a CTRL-Break on Win32 and a CTRL-\ on Solaris
13226 causes the VM to send this event to the agent.
13227 </description>
13228 <origin>jvmpi</origin>
13229 <capabilities>
13230 </capabilities>
13231 <parameters>
13232 </parameters>
13233 </event>
13234
13235 <event label="Monitor Contended Enter"
13236 id="MonitorContendedEnter" const="JVMTI_EVENT_MONITOR_CONTENDED_ENTER" filtered="thread" num="75">
13237 <description>
13238 Sent when a thread is attempting to enter a Java programming language
13239 monitor already acquired by another thread.
13240 </description>
13241 <origin>jvmpi</origin>
13242 <capabilities>
13243 <required id="can_generate_monitor_events"></required>
13244 </capabilities>
13245 <parameters>
13246 <param id="jni_env">
13247 <outptr>
13248 <struct>JNIEnv</struct>
13249 </outptr>
13250 <description>
13251 The JNI environment of the event (current) thread
13252 </description>
13253 </param>
13254 <param id="thread">
13255 <jthread/>
13256 <description>
13257 JNI local reference to the thread
13258 attempting to enter the monitor
13259 </description>
13260 </param>
13261 <param id="object">
13262 <jobject/>
13263 <description>
13264 JNI local reference to the monitor
13265 </description>
13266 </param>
13267 </parameters>
13268 </event>
13269
13270 <event label="Monitor Contended Entered"
13271 id="MonitorContendedEntered" const="JVMTI_EVENT_MONITOR_CONTENDED_ENTERED" filtered="thread" num="76">
13272 <description>
13273 Sent when a thread enters a Java programming language
13274 monitor after waiting for it to be released by another thread.
13275 </description>
13276 <origin>jvmpi</origin>
13277 <capabilities>
13278 <required id="can_generate_monitor_events"></required>
13279 </capabilities>
13280 <parameters>
13281 <param id="jni_env">
13282 <outptr>
13283 <struct>JNIEnv</struct>
13284 </outptr>
13285 <description>
13286 The JNI environment of the event (current) thread
13287 </description>
13288 </param>
13289 <param id="thread">
13290 <jthread/>
13291 <description>
13292 JNI local reference to the thread entering
13293 the monitor
13294 </description>
13295 </param>
13296 <param id="object">
13297 <jobject/>
13298 <description>
13299 JNI local reference to the monitor
13300 </description>
13301 </param>
13302 </parameters>
13303 </event>
13304
13305 <event label="Monitor Wait"
13306 id="MonitorWait" const="JVMTI_EVENT_MONITOR_WAIT" filtered="thread" num="73">
13307 <description>
13308 Sent when a thread is about to wait on an object.
13309 </description>
13310 <origin>jvmpi</origin>
13311 <capabilities>
13312 <required id="can_generate_monitor_events"></required>
13313 </capabilities>
13314 <parameters>
13315 <param id="jni_env">
13316 <outptr>
13317 <struct>JNIEnv</struct>
13318 </outptr>
13319 <description>
13320 The JNI environment of the event (current) thread
13321 </description>
13322 </param>
13323 <param id="thread">
13324 <jthread/>
13325 <description>
13326 JNI local reference to the thread about to wait
13327 </description>
13328 </param>
13329 <param id="object">
13330 <jobject/>
13331 <description>
13332 JNI local reference to the monitor
13333 </description>
13334 </param>
13335 <param id="timeout">
13336 <jlong/>
13337 <description>
13338 The number of milliseconds the thread will wait
13339 </description>
13340 </param>
13341 </parameters>
13342 </event>
13343
13344 <event label="Monitor Waited"
13345 id="MonitorWaited" const="JVMTI_EVENT_MONITOR_WAITED" filtered="thread" num="74">
13346 <description>
13347 Sent when a thread finishes waiting on an object.
13348 </description>
13349 <origin>jvmpi</origin>
13350 <capabilities>
13351 <required id="can_generate_monitor_events"></required>
13352 </capabilities>
13353 <parameters>
13354 <param id="jni_env">
13355 <outptr>
13356 <struct>JNIEnv</struct>
13357 </outptr>
13358 <description>
13359 The JNI environment of the event (current) thread
13360 </description>
13361 </param>
13362 <param id="thread">
13363 <jthread/>
13364 <description>
13365 JNI local reference to the thread that was finished waiting
13366 </description>
13367 </param>
13368 <param id="object">
13369 <jobject/>
13370 <description>
13371 JNI local reference to the monitor.
13372 </description>
13373 </param>
13374 <param id="timed_out">
13375 <jboolean/>
13376 <description>
13377 True if the monitor timed out
13378 </description>
13379 </param>
13380 </parameters>
13381 </event>
13382
13383 <event label="Resource Exhausted"
13384 id="ResourceExhausted" const="JVMTI_EVENT_RESOURCE_EXHAUSTED" num="80"
13385 since="1.1">
13386 <description>
13387 Sent when a VM resource needed by a running application has been exhausted.
13388 Except as required by the optional capabilities, the set of resources
13389 which report exhaustion is implementation dependent.
13390 <p/>
13391 The following bit flags define the properties of the resource exhaustion:
13392 <constants id="jvmtiResourceExhaustionFlags"
13393 label="Resource Exhaustion Flags"
13394 kind="bits"
13395 since="1.1">
13396 <constant id="JVMTI_RESOURCE_EXHAUSTED_OOM_ERROR" num="0x0001">
13397 After this event returns, the VM will throw a
13398 <code>java.lang.OutOfMemoryError</code>.
13399 </constant>
13400 <constant id="JVMTI_RESOURCE_EXHAUSTED_JAVA_HEAP" num="0x0002">
13401 The VM was unable to allocate memory from the <tm>Java</tm>
13402 platform <i>heap</i>.
13403 The <i>heap</i> is the runtime
13404 data area from which memory for all class instances and
13405 arrays are allocated.
13406 </constant>
13407 <constant id="JVMTI_RESOURCE_EXHAUSTED_THREADS" num="0x0004">
13408 The VM was unable to create a thread.
13409 </constant>
13410 </constants>
13411 </description>
13412 <origin>new</origin>
13413 <capabilities>
13414 <capability id="can_generate_resource_exhaustion_heap_events">
13415 Can generate events when the VM is unable to allocate memory from the
13416 <internallink id="JVMTI_RESOURCE_EXHAUSTED_JAVA_HEAP">heap</internallink>.
13417 </capability>
13418 <capability id="can_generate_resource_exhaustion_threads_events">
13419 Can generate events when the VM is unable to
13420 <internallink id="JVMTI_RESOURCE_EXHAUSTED_THREADS">create
13421 a thread</internallink>.
13422 </capability>
13423 </capabilities>
13424 <parameters>
13425 <param id="jni_env">
13426 <outptr>
13427 <struct>JNIEnv</struct>
13428 </outptr>
13429 <description>
13430 The JNI environment of the event (current) thread
13431 </description>
13432 </param>
13433 <param id="flags">
13434 <jint/>
13435 <description>
13436 Flags defining the properties of the of resource exhaustion
13437 as specified by the
13438 <internallink id="jvmtiResourceExhaustionFlags">Resource
13439 Exhaustion Flags</internallink>.
13440 </description>
13441 </param>
13442 <param id="reserved">
13443 <vmbuf><void/></vmbuf>
13444 <description>
13445 Reserved.
13446 </description>
13447 </param>
13448 <param id="description">
13449 <vmbuf><char/></vmbuf>
13450 <description>
13451 Description of the resource exhaustion, encoded as a
13452 <internallink id="mUTF">modified UTF-8</internallink> string.
13453 </description>
13454 </param>
13455 </parameters>
13456 </event>
13457
13458 <event label="VM Object Allocation"
13459 id="VMObjectAlloc" const="JVMTI_EVENT_VM_OBJECT_ALLOC" num="84">
13460 <description>
13461 Sent when a method causes the virtual machine to allocate an
13462 Object visible to Java programming language code and the
13463 allocation is not detectable by other intrumentation mechanisms.
13464 Generally object allocation should be detected by instrumenting
13465 the bytecodes of allocating methods.
13466 Object allocation generated in native code by JNI function
13467 calls should be detected using
13468 <internallink id="jniIntercept">JNI function interception</internallink>.
13469 Some methods might not have associated bytecodes and are not
13470 native methods, they instead are executed directly by the
13471 VM. These methods should send this event.
13472 Virtual machines which are incapable of bytecode instrumentation
13473 for some or all of their methods can send this event.
13474 <p/>
13475 Typical examples where this event might be sent:
13476 <ul>
13477 <li>Reflection -- for example, <code>java.lang.Class.newInstance()</code></li>
13478 <li>Methods not represented by bytecodes -- for example, VM intrinsics and
13479 J2ME preloaded classes</li>
13480 </ul>
13481 Cases where this event would not be generated:
13482 <ul>
13483 <li>Allocation due to bytecodes -- for example, the <code>new</code>
13484 and <code>newarray</code> VM instructions</li>
13485 <li>Allocation due to JNI function calls -- for example,
13486 <code>AllocObject</code></li>
13487 <li>Allocations during VM initialization</li>
13488 <li>VM internal objects</li>
13489 </ul>
13490 </description>
13491 <origin>new</origin>
13492 <capabilities>
13493 <required id="can_generate_vm_object_alloc_events"></required>
13494 </capabilities>
13495 <parameters>
13496 <param id="jni_env">
13497 <outptr>
13498 <struct>JNIEnv</struct>
13499 </outptr>
13500 <description>
13501 The JNI environment of the event (current) thread
13502 </description>
13503 </param>
13504 <param id="thread">
13505 <jthread/>
13506 <description>
13507 Thread allocating the object.
13508 </description>
13509 </param>
13510 <param id="object">
13511 <jobject/>
13512 <description>
13513 JNI local reference to the object that was allocated
13514 </description>
13515 </param>
13516 <param id="object_klass">
13517 <jclass/>
13518 <description>
13519 JNI local reference to the class of the object
13520 </description>
13521 </param>
13522 <param id="size">
13523 <jlong/>
13524 <description>
13525 Size of the object (in bytes). See <functionlink id="GetObjectSize"/>.
13526 </description>
13527 </param>
13528 </parameters>
13529 </event>
13530
13531 <event label="Object Free"
13532 id="ObjectFree" const="JVMTI_EVENT_OBJECT_FREE" num="83">
13533 <description>
13534 An Object Free event is sent when the garbage collector frees an object.
13535 Events are only sent for tagged objects--see
13536 <internallink id="Heap">heap functions</internallink>.
13537 <p/>
13538 The event handler must not use JNI functions and
13539 must not use <jvmti/> functions except those which
13540 specifically allow such use (see the raw monitor, memory management,
13541 and environment local storage functions).
13542 </description>
13543 <origin>new</origin>
13544 <capabilities>
13545 <required id="can_generate_object_free_events"></required>
13546 </capabilities>
13547 <parameters>
13548 <param id="tag">
13549 <jlong/>
13550 <description>
13551 The freed object's tag
13552 </description>
13553 </param>
13554 </parameters>
13555 </event>
13556
13557 <event label="Garbage Collection Start"
13558 id="GarbageCollectionStart" const="JVMTI_EVENT_GARBAGE_COLLECTION_START" num="81">
13559 <description>
13560 A Garbage Collection Start event is sent when a
13561 garbage collection pause begins.
13562 Only stop-the-world collections are reported--that is, collections during
13563 which all threads cease to modify the state of the Java virtual machine.
13564 This means that some collectors will never generate these events.
13565 This event is sent while the VM is still stopped, thus
13566 the event handler must not use JNI functions and
13567 must not use <jvmti/> functions except those which
13568 specifically allow such use (see the raw monitor, memory management,
13569 and environment local storage functions).
13570 <p/>
13571 This event is always sent as a matched pair with
13572 <eventlink id="GarbageCollectionFinish"/>
13573 (assuming both events are enabled) and no garbage collection
13574 events will occur between them.
13575 </description>
13576 <origin>new</origin>
13577 <capabilities>
13578 <required id="can_generate_garbage_collection_events"></required>
13579 </capabilities>
13580 <parameters>
13581 </parameters>
13582 </event>
13583
13584 <event label="Garbage Collection Finish"
13585 id="GarbageCollectionFinish" const="JVMTI_EVENT_GARBAGE_COLLECTION_FINISH" num="82">
13586 <description>
13587 A Garbage Collection Finish event is sent when a
13588 garbage collection pause ends.
13589 This event is sent while the VM is still stopped, thus
13590 the event handler must not use JNI functions and
13591 must not use <jvmti/> functions except those which
13592 specifically allow such use (see the raw monitor, memory management,
13593 and environment local storage functions).
13594 <p/>
13595 Some agents may need to do post garbage collection operations that
13596 require the use of the disallowed <jvmti/> or JNI functions. For these
13597 cases an agent thread can be created which waits on a raw monitor,
13598 and the handler for the Garbage Collection Finish event simply
13599 notifies the raw monitor
13600 <p/>
13601 This event is always sent as a matched pair with
13602 <eventlink id="GarbageCollectionStart"/> (assuming both events are enabled).
13603 <issue>
13604 The most important use of this event is to provide timing information,
13605 and thus additional information is not required. However,
13606 information about the collection which is "free" should be included -
13607 what that information is needs to be determined.
13608 </issue>
13609 </description>
13610 <origin>new</origin>
13611 <capabilities>
13612 <required id="can_generate_garbage_collection_events"></required>
13613 </capabilities>
13614 <parameters>
13615 </parameters>
13616 </event>
13617
13618 <elide>
13619 <event label="Verbose Output" phase="any"
13620 id="VerboseOutput" const="JVMTI_EVENT_VERBOSE_OUTPUT" num="85">
13621 <description>
13622 Send verbose messages as strings.
13623 <issue>
13624 This format is extremely fragile, as it can change with each
13625 platform, collector and version. Alternatives include:
13626 <ul>
13627 <li>building off Java programming language M and M APIs</li>
13628 <li>XML</li>
13629 <li>key/value pairs</li>
13630 <li>removing it</li>
13631 </ul>
13632 </issue>
13633 <issue>
13634 Though this seemed trivial to implement.
13635 In the RI it appears this will be quite complex.
13636 </issue>
13637 </description>
13638 <origin>new</origin>
13639 <capabilities>
13640 </capabilities>
13641 <parameters>
13642 <param id="flag">
13643 <enum>jvmtiVerboseFlag</enum>
13644 <description>
13645 Which verbose output is being sent.
13646 </description>
13647 </param>
13648 <param id="message">
13649 <vmbuf><char/></vmbuf>
13650 <description>
13651 Message text, encoded as a
13652 <internallink id="mUTF">modified UTF-8</internallink> string.
13653 </description>
13654 </param>
13655 </parameters>
13656 </event>
13657 </elide>
13658
13659 </eventsection>
13660
13661 <datasection>
13662 <intro>
13663 <jvmti/> extends the data types defined by JNI.
13664 </intro>
13665 <basetypes id="jniTypes" label="JNI Types Used in the JVM Tool Interface">
13666 <basetype id="jboolean">
13667 <description>
13668 Holds a Java programming language <code>boolean</code>.
13669 Unsigned 8 bits.
13670 </description>
13671 </basetype>
13672 <basetype id="jchar">
13673 <description>
13674 Holds a Java programming language <code>char</code>.
13675 Unsigned 16 bits.
13676 </description>
13677 </basetype>
13678 <basetype id="jint">
13679 <description>
13680 Holds a Java programming language <code>int</code>.
13681 Signed 32 bits.
13682 </description>
13683 </basetype>
13684 <basetype id="jlong">
13685 <description>
13686 Holds a Java programming language <code>long</code>.
13687 Signed 64 bits.
13688 </description>
13689 </basetype>
13690 <basetype id="jfloat">
13691 <description>
13692 Holds a Java programming language <code>float</code>.
13693 32 bits.
13694 </description>
13695 </basetype>
13696 <basetype id="jdouble">
13697 <description>
13698 Holds a Java programming language <code>double</code>.
13699 64 bits.
13700 </description>
13701 </basetype>
13702 <basetype id="jobject">
13703 <description>
13704 Holds a Java programming language object.
13705 </description>
13706 </basetype>
13707 <basetype id="jclass">
13708 <description>
13709 Holds a Java programming language class.
13710 </description>
13711 </basetype>
13712 <basetype id="jvalue">
13713 <description>
13714 Is a union of all primitive types and <code>jobject</code>. Thus, holds any Java
13715 programming language value.
13716 </description>
13717 </basetype>
13718 <basetype id="jfieldID">
13719 <description>
13720 Identifies a Java programming language field.
13721 <code>jfieldID</code>s returned by <jvmti/> functions and events may be
13722 safely stored.
13723 </description>
13724 </basetype>
13725 <basetype id="jmethodID">
13726 <description>
13727 Identifies a Java programming language method, initializer, or constructor.
13728 <code>jmethodID</code>s returned by <jvmti/> functions and events may be
13729 safely stored. However, if the class is unloaded, they become invalid
13730 and must not be used.
13731 </description>
13732 </basetype>
13733 <basetype id="JNIEnv">
13734 <description>
13735 Pointer to the JNI function table. Pointer to this (<code>JNIEnv *</code>)
13736 is a JNI environment.
13737 </description>
13738 </basetype>
13739 </basetypes>
13740
13741 <basetypes id="jvmtiTypes" label="JVM Tool Interface Base Types">
13742 <basetype id="jvmtiEnv">
13743 <description>
13744 The <jvmti/> <internallink id="environments">environment</internallink> pointer.
13745 See the <internallink id="FunctionSection">Function Section</internallink>.
13746 <code>jvmtiEnv</code> points to the
13747 <internallink id="FunctionTable">function table</internallink> pointer.
13748 </description>
13749 </basetype>
13750 <basetype id="jthread">
13751 <definition>typedef jobject jthread;</definition>
13752 <description>
13753 Subtype of <datalink id="jobject"></datalink> that holds a thread.
13754 </description>
13755 </basetype>
13756 <basetype id="jthreadGroup">
13757 <definition>typedef jobject jthreadGroup;</definition>
13758 <description>
13759 Subtype of <datalink id="jobject"></datalink> that holds a thread group.
13760 </description>
13761 </basetype>
13762 <basetype id="jlocation">
13763 <definition>typedef jlong jlocation;</definition>
13764 <description>
13765 A 64 bit value, representing a monotonically increasing
13766 executable position within a method.
13767 <code>-1</code> indicates a native method.
13768 See <functionlink id="GetJLocationFormat"></functionlink> for the format on a
13769 given VM.
13770 </description>
13771 </basetype>
13772 <basetype id="jrawMonitorID">
13773 <definition>struct _jrawMonitorID;
13774 typedef struct _jrawMonitorID *jrawMonitorID;</definition>
13775 <description>
13776 A raw monitor.
13777 </description>
13778 </basetype>
13779 <basetype id="jvmtiError">
13780 <description>
13781 Holds an error return code.
13782 See the <internallink id="ErrorSection">Error section</internallink> for possible values.
13783 <example>
13784 typedef enum {
13785 JVMTI_ERROR_NONE = 0,
13786 JVMTI_ERROR_INVALID_THREAD = 10,
13787 ...
13788 } jvmtiError;
13789 </example>
13790 </description>
13791 </basetype>
13792 <basetype id="jvmtiEvent">
13793 <description>
13794 An identifier for an event type.
13795 See the <internallink id="EventSection">Event section</internallink> for possible values.
13796 It is guaranteed that future versions of this specification will
13797 never assign zero as an event type identifier.
13798 <example>
13799 typedef enum {
13800 JVMTI_EVENT_SINGLE_STEP = 1,
13801 JVMTI_EVENT_BREAKPOINT = 2,
13802 ...
13803 } jvmtiEvent;
13804 </example>
13805 </description>
13806 </basetype>
13807 <basetype id="jvmtiEventCallbacks" name="eventCallbacks">
13808 <description>
13809 The callbacks used for events.
13810 <example>
13811 typedef struct {
13812 jvmtiEventVMInit VMInit;
13813 jvmtiEventVMDeath VMDeath;
13814 ...
13815 } jvmtiEventCallbacks;
13816 </example>
13817 See <internallink id="jvmtiEventCallbacks">event callbacks</internallink>
13818 for the complete structure.
13819 <p/>
13820 Where, for example, the VM initialization callback is defined:
13821 <example>
13822 typedef void (JNICALL *jvmtiEventVMInit)
13823 (jvmtiEnv *jvmti_env,
13824 JNIEnv* jni_env,
13825 jthread thread);
13826 </example>
13827 See the individual events for the callback function definition.
13828 </description>
13829 </basetype>
13830 <basetype id="jniNativeInterface">
13831 <definition>typedef struct JNINativeInterface_ jniNativeInterface;</definition>
13832 <description>
13833 Typedef for the JNI function table <code>JNINativeInterface</code>
13834 defined in the
13835 <externallink id="jni/functions.html#interface-function-table">
13836 JNI Specification</externallink>.
13837 The JNI reference implementation defines this with an underscore.
13838 </description>
13839 </basetype>
13840 </basetypes>
13841
13842 </datasection>
13843
13844 <issuessection label="Issues">
13845 <intro id="suspendRequired" label="Resolved Issue: Suspend - Required or Automatic">
13846 JVMDI requires that the agent suspend threads before calling
13847 certain sensitive functions. JVMPI requires garbage collection to be
13848 disabled before calling certain sensitive functions.
13849 It was suggested that rather than have this requirement, that
13850 VM place itself in a suitable state before performing an
13851 operation. This makes considerable sense since each VM
13852 knows its requirements and can most easily arrange a
13853 safe state.
13854 <p/>
13855 The ability to externally suspend/resume threads will, of
13856 course, remain. The ability to enable/disable garbage collection will not.
13857 <p/>
13858 This issue is resolved--suspend will not
13859 be required. The spec has been updated to reflect this.
13860 </intro>
13861
13862 <intro id="stackSampling" label="Resolved Issue: Call Stack Sampling">
13863 There are a variety of approaches to sampling call stacks.
13864 The biggest bifurcation is between VM controlled and agent
13865 controlled.
13866 <p/>
13867 This issue is resolved--agent controlled
13868 sampling will be the approach.
13869 </intro>
13870
13871 <intro id="threadRepresentation" label="Resolved Issue: Thread Representation">
13872 JVMDI represents threads as jthread. JVMPI primarily
13873 uses JNIEnv* to represent threads.
13874 <p/>
13875 The Expert Group has chosen jthread as the representation
13876 for threads in <jvmti/>.
13877 JNIEnv* is sent by
13878 events since it is needed to JNI functions. JNIEnv, per the
13879 JNI spec, are not supposed to be used outside their thread.
13880 </intro>
13881
13882 <intro id="design" label="Resolved Issue: Method Representation">
13883 The JNI spec allows an implementation to depend on jclass/jmethodID
13884 pairs, rather than simply a jmethodID, to reference a method.
13885 JVMDI, for consistency, choose the same representation.
13886 JVMPI, however, specifies that a jmethodID alone maps to a
13887 method. Both of the Sun <tm>J2SE</tm> virtual machines (Classic and <tm>HotSpot</tm>) store
13888 pointers in jmethodIDs, and as a result, a jmethodID is sufficient.
13889 In fact, any JVM implementation that supports JVMPI must have
13890 such a representation.
13891 <jvmti/> will use jmethodID as a unique representation of a method
13892 (no jclass is used).
13893 There should be efficiency gains, particularly in
13894 functionality like stack dumping, to this representation.
13895 <p/>
13896 Note that fields were not used in JVMPI and that the access profile
13897 of fields differs from methods--for implementation efficiency
13898 reasons, a jclass/jfieldID pair will still be needed for field
13899 reference.
13900 </intro>
13901
13902 <intro id="localReferenceIssue" label="Resolved Issue: Local References">
13903 Functions return local references.
13904 </intro>
13905
13906 <intro id="frameRep" label="Resolved Issue: Representation of frames">
13907 In JVMDI, a frame ID is used to represent a frame. Problem with this
13908 is that a VM must track when a frame becomes invalid, a far better
13909 approach, and the one used in <jvmti/>, is to reference frames by depth.
13910 </intro>
13911
13912 <intro id="requiredCapabilities" label="Issue: Required Capabilities">
13913 Currently, having a required capabilities means that the functionality
13914 is optional. Capabilities are useful even for required functionality
13915 since they can inform the VM is needed set-up. Thus, there should be
13916 a set of capabilities that a conformant implementation must provide
13917 (if requested during Agent_OnLoad).
13918 </intro>
13919
13920 <intro id="taghint" label="Proposal: add tag hint function">
13921 A hint of the percentage of objects that will be tagged would
13922 help the VM pick a good implementation.
13923 </intro>
13924
13925 <intro id="moreMonitorQueries" label="Request: More Monitor Quires">
13926 How difficult or easy would be to extend the monitor_info category to include
13927 <pre>
13928 - current number of monitors
13929 - enumeration of monitors
13930 - enumeration of threads waiting on a given monitor
13931 </pre>
13932 The reason for my question is the fact that current get_monitor_info support
13933 requires the agent to specify a given thread to get the info which is probably
13934 OK in the profiling/debugging space, while in the monitoring space the agent
13935 could be watching the monitor list and then decide which thread to ask for
13936 the info. You might ask why is this important for monitoring .... I think it
13937 can aid in the detection/prediction of application contention caused by hot-locks.
13938 </intro>
13939 </issuessection>
13940
13941 <changehistory id="ChangeHistory" update="09/05/07">
13942 <intro>
13943 The <jvmti/> specification is an evolving document with major, minor,
13944 and micro version numbers.
13945 A released version of the specification is uniquely identified
13946 by its major and minor version.
13947 The functions, events, and capabilities in this specification
13948 indicate a "Since" value which is the major and minor version in
13949 which it was introduced.
13950 The version of the specification implemented by the VM can
13951 be retrieved at runtime with the <functionlink id="GetVersionNumber"/>
13952 function.
13953 </intro>
13954 <change date="14 Nov 2002">
13955 Converted to XML document.
13956 </change>
13957 <change date="14 Nov 2002">
13958 Elided heap dump functions (for now) since what was there
13959 was wrong.
13960 </change>
13961 <change date="18 Nov 2002">
13962 Added detail throughout.
13963 </change>
13964 <change date="18 Nov 2002">
13965 Changed JVMTI_THREAD_STATUS_RUNNING to JVMTI_THREAD_STATUS_RUNNABLE.
13966 </change>
13967 <change date="19 Nov 2002">
13968 Added AsyncGetStackTrace.
13969 </change>
13970 <change date="19 Nov 2002">
13971 Added jframeID return to GetStackTrace.
13972 </change>
13973 <change date="19 Nov 2002">
13974 Elided GetCurrentFrame and GetCallingFrame functions (for now) since what was there
13975 since they are redundant with GetStackTrace.
13976 </change>
13977 <change date="19 Nov 2002">
13978 Elided ClearAllBreakpoints since it has always been redundant.
13979 </change>
13980 <change date="19 Nov 2002">
13981 Added GetSystemProperties.
13982 </change>
13983 <change date="19 Nov 2002">
13984 Changed the thread local storage functions to use jthread.
13985 </change>
13986 <change date="20 Nov 2002">
13987 Added GetJLocationFormat.
13988 </change>
13989 <change date="22 Nov 2002">
13990 Added events and introductory text.
13991 </change>
13992 <change date="22 Nov 2002">
13993 Cross reference type and constant definitions.
13994 </change>
13995 <change date="24 Nov 2002">
13996 Added DTD.
13997 </change>
13998 <change date="24 Nov 2002">
13999 Added capabilities function section.
14000 </change>
14001 <change date="29 Nov 2002">
14002 Assign capabilities to each function and event.
14003 </change>
14004 <change date="29 Nov 2002">
14005 Add <internallink id="jniIntercept">JNI interception functions</internallink>.
14006 </change>
14007 <change date="30 Nov 2002">
14008 Auto generate SetEventNotificationMode capabilities.
14009 </change>
14010 <change date="30 Nov 2002">
14011 Add <eventlink id="VMObjectAlloc"></eventlink> event.
14012 </change>
14013 <change date="30 Nov 2002">
14014 Add <eventlink id="DynamicCodeGenerated"></eventlink> event.
14015 </change>
14016 <change date="30 Nov 2002">
14017 Add const to declarations.
14018 </change>
14019 <change date="30 Nov 2002">
14020 Change method exit and frame pop to send on exception.
14021 </change>
14022 <change date="1 Dec 2002">
14023 Add ForceGarbageCollection.
14024 </change>
14025 <change date="2 Dec 2002">
14026 Redo Xrun section; clarify GetStackTrace and add example;
14027 Fix width problems; use "agent" consistently.
14028 </change>
14029 <change date="8 Dec 2002">
14030 Remove previous start-up intro.
14031 Add <internallink id="environments"><jvmti/> Environments</internallink>
14032 section.
14033 </change>
14034 <change date="8 Dec 2002">
14035 Add <functionlink id="DisposeEnvironment"></functionlink>.
14036 </change>
14037 <change date="9 Dec 2002">
14038 Numerous minor updates.
14039 </change>
14040 <change date="15 Dec 2002">
14041 Add heap profiling functions added:
14042 get/set annotation, iterate live objects/heap.
14043 Add heap profiling functions place holder added:
14044 heap roots.
14045 Heap profiling event added: object free.
14046 Heap profiling event redesigned: vm object allocation.
14047 Heap profiling event placeholders added: garbage collection start/finish.
14048 Native method bind event added.
14049 </change>
14050 <change date="19 Dec 2002">
14051 Revamp suspend/resume functions.
14052 Add origin information with jvmdi tag.
14053 Misc fixes.
14054 </change>
14055 <change date="24 Dec 2002">
14056 Add semantics to types.
14057 </change>
14058 <change date="27 Dec 2002">
14059 Add local reference section.
14060 Autogenerate parameter descriptions from types.
14061 </change>
14062 <change date="28 Dec 2002">
14063 Document that RunAgentThread sends threadStart.
14064 </change>
14065 <change date="29 Dec 2002">
14066 Remove redundant local ref and dealloc warning.
14067 Convert GetRawMonitorName to allocated buffer.
14068 Add GenerateEvents.
14069 </change>
14070 <change date="30 Dec 2002">
14071 Make raw monitors a type and rename to "jrawMonitorID".
14072 </change>
14073 <change date="1 Jan 2003">
14074 Include origin information.
14075 Clean-up JVMDI issue references.
14076 Remove Deallocate warnings which are now automatically generated.
14077 </change>
14078 <change date="2 Jan 2003">
14079 Fix representation issues for jthread.
14080 </change>
14081 <change date="3 Jan 2003">
14082 Make capabilities buffered out to 64 bits - and do it automatically.
14083 </change>
14084 <change date="4 Jan 2003">
14085 Make constants which are enumeration into enum types.
14086 Parameters now of enum type.
14087 Clean-up and index type section.
14088 Replace remaining datadef entities with callback.
14089 </change>
14090 <change date="7 Jan 2003">
14091 Correct GenerateEvents description.
14092 More internal semantics work.
14093 </change>
14094 <change date="9 Jan 2003">
14095 Replace previous GetSystemProperties with two functions
14096 which use allocated information instead fixed.
14097 Add SetSystemProperty.
14098 More internal semantics work.
14099 </change>
14100 <change date="12 Jan 2003">
14101 Add varargs to end of SetEventNotificationMode.
14102 </change>
14103 <change date="20 Jan 2003">
14104 Finish fixing spec to reflect that alloc sizes are jlong.
14105 </change>
14106 <change date="22 Jan 2003">
14107 Allow NULL as RunAgentThread arg.
14108 </change>
14109 <change date="22 Jan 2003">
14110 Fixed names to standardized naming convention
14111 Removed AsyncGetStackTrace.
14112 </change>
14113 <change date="29 Jan 2003">
14114 Since we are using jthread, removed GetThread.
14115 </change>
14116 <change date="31 Jan 2003">
14117 Change GetFieldName to allow NULLs like GetMethodName.
14118 </change>
14119 <change date="29 Feb 2003" version="v40">
14120 Rewrite the introductory text, adding sections on
14121 start-up, environments and bytecode instrumentation.
14122 Change the command line arguments per EG discussions.
14123 Add an introduction to the capabilities section.
14124 Add the extension mechanism category and functions.
14125 Mark for deletion, but clarified anyhow, SuspendAllThreads.
14126 Rename IterateOverLiveObjects to IterateOverReachableObjects and
14127 change the text accordingly.
14128 Clarify IterateOverHeap.
14129 Clarify CompiledMethodLoad.
14130 Discuss prerequisite state for Calling Functions.
14131 Clarify SetAllocationHooks.
14132 Added issues ("To be resolved:") through-out.
14133 And so on...
14134 </change>
14135 <change date="6 Mar 2003" version="v41">
14136 Remove struct from the call to GetOwnedMonitorInfo.
14137 Automatically generate most error documentation, remove
14138 (rather broken) hand written error doc.
14139 Better describe capability use (empty initial set).
14140 Add min value to jint params.
14141 Remove the capability can_access_thread_local_storage.
14142 Rename error JVMTI_ERROR_NOT_IMPLEMENTED to JVMTI_ERROR_MUST_POSSESS_CAPABILITY;
14143 same for *NOT_IMPLEMENTED.
14144 Description fixes.
14145 </change>
14146 <change date="8 Mar 2003" version="v42">
14147 Rename GetClassSignature to GetClassName.
14148 Rename IterateOverClassObjects to IterateOverInstancesOfClass.
14149 Remove GetMaxStack (operand stack isn't used in <jvmti/>).
14150 Description fixes: define launch-time, remove native frame pop
14151 from PopFrame, and assorted clarifications.
14152 </change>
14153 <change date="8 Mar 2003" version="v43">
14154 Fix minor editing problem.
14155 </change>
14156 <change date="10 Mar 2003" version="v44">
14157 Add phase information.
14158 Remap (compact) event numbers.
14159 </change>
14160 <change date="11 Mar 2003" version="v45">
14161 More phase information - allow "any".
14162 Elide raw monitor queries and events.
14163 Minor description fixes.
14164 </change>
14165 <change date="12 Mar 2003" version="v46">
14166 Add GetPhase.
14167 Use "phase" through document.
14168 Elide GetRawMonitorName.
14169 Elide GetObjectMonitors.
14170 </change>
14171 <change date="12 Mar 2003" version="v47">
14172 Fixes from link, XML, and spell checking.
14173 Auto-generate the callback structure.
14174 </change>
14175 <change date="13 Mar 2003" version="v48">
14176 One character XML fix.
14177 </change>
14178 <change date="13 Mar 2003" version="v49">
14179 Change function parameter names to be consistent with
14180 event parameters (fooBarBaz becomes foo_bar_baz).
14181 </change>
14182 <change date="14 Mar 2003" version="v50">
14183 Fix broken link. Fix thread markers.
14184 </change>
14185 <change date="14 Mar 2003" version="v51">
14186 Change constants so they are under 128 to workaround
14187 compiler problems.
14188 </change>
14189 <change date="23 Mar 2003" version="v52">
14190 Overhaul capabilities. Separate GetStackTrace into
14191 GetStackTrace and GetStackFrames.
14192 </change>
14193 <change date="8 Apr 2003" version="v54">
14194 Use depth instead of jframeID to reference frames.
14195 Remove the now irrelevant GetCurrentFrame, GetCallerFrame and GetStackFrames.
14196 Remove frame arg from events.
14197 </change>
14198 <change date="9 Apr 2003" version="v55">
14199 Remove GetObjectWithAnnotation since tests show bufferred approach more efficient.
14200 Add missing annotation_count to GetObjectsWithAnnotations
14201 </change>
14202 <change date="10 Apr 2003" version="v56">
14203 Remove confusing parenthetical statement in GetObjectsWithAnnotations
14204 </change>
14205 <change date="13 Apr 2003" version="v58">
14206 Replace jclass/jmethodID representation of method with simply jmethodID;
14207 Pass JvmtiEnv* as first arg of every event; remove JNIEnv* where inappropriate.
14208 Replace can_access_frames with can_access_local_variables; remove from purely stack access.
14209 Use can_get_synthetic_attribute; fix description.
14210 Clarify that zero length arrays must be deallocated.
14211 Clarify RelinquishCapabilities.
14212 Generalize JVMTI_ERROR_VM_DEAD to JVMTI_ERROR_WRONG_PHASE.
14213 </change>
14214 <change date="27 Apr 2003" version="v59">
14215 Remove lingering indirect references to OBSOLETE_METHOD_ID.
14216 </change>
14217 <change date="4 May 2003" version="v60">
14218 Allow DestroyRawMonitor during OnLoad.
14219 </change>
14220 <change date="7 May 2003" version="v61">
14221 Added not monitor owner error return to DestroyRawMonitor.
14222 </change>
14223 <change date="13 May 2003" version="v62">
14224 Clarify semantics of raw monitors.
14225 Change flags on <code>GetThreadStatus</code>.
14226 <code>GetClassLoader</code> return NULL for the bootstrap class loader.
14227 Add <code>GetClassName</code> issue.
14228 Define local variable signature.
14229 Disallow zero in annotations array of <code>GetObjectsWithAnnotations</code>.
14230 Remove over specification in <code>GetObjectsWithAnnotations</code>.
14231 Elide <code>SetAllocationHooks</code>.
14232 Elide <code>SuspendAllThreads</code>.
14233 </change>
14234 <change date="14 May 2003" version="v63">
14235 Define the data type <code>jvmtiEventCallbacks</code>.
14236 Zero length allocations return NULL.
14237 Keep SetAllocationHooks in JVMDI, but remove from <jvmti/>.
14238 Add JVMTI_THREAD_STATUS_FLAG_INTERRUPTED.
14239 </change>
14240 <change date="15 May 2003" version="v64">
14241 Better wording, per review.
14242 </change>
14243 <change date="15 May 2003" version="v65">
14244 First Alpha.
14245 Make jmethodID and jfieldID unique, jclass not used.
14246 </change>
14247 <change date="27 May 2003" version="v66">
14248 Fix minor XSLT errors.
14249 </change>
14250 <change date="13 June 2003" version="v67">
14251 Undo making jfieldID unique (jmethodID still is).
14252 </change>
14253 <change date="17 June 2003" version="v68">
14254 Changes per June 11th Expert Group meeting --
14255 Overhaul Heap functionality: single callback,
14256 remove GetHeapRoots, add reachable iterators,
14257 and rename "annotation" to "tag".
14258 NULL thread parameter on most functions is current
14259 thread.
14260 Add timers.
14261 Remove ForceExit.
14262 Add GetEnvironmentLocalStorage.
14263 Add verbose flag and event.
14264 Add AddToBootstrapClassLoaderSearch.
14265 Update ClassFileLoadHook.
14266 </change>
14267 <change date="18 June 2003" version="v69">
14268 Clean up issues sections.
14269 Rename GetClassName back to GetClassSignature and
14270 fix description.
14271 Add generic signature to GetClassSignature,
14272 GetFieldSignature, GetMethodSignature, and
14273 GetLocalVariableTable.
14274 Elide EstimateCostOfCapabilities.
14275 Clarify that the system property functions operate
14276 on the VM view of system properties.
14277 Clarify Agent_OnLoad.
14278 Remove "const" from JNIEnv* in events.
14279 Add metadata accessors.
14280 </change>
14281 <change date="18 June 2003" version="v70">
14282 Add start_depth to GetStackTrace.
14283 Move system properties to a new category.
14284 Add GetObjectSize.
14285 Remove "X" from command line flags.
14286 XML, HTML, and spell check corrections.
14287 </change>
14288 <change date="19 June 2003" version="v71">
14289 Fix JVMTI_HEAP_ROOT_THREAD to be 6.
14290 Make each synopsis match the function name.
14291 Fix unclear wording.
14292 </change>
14293 <change date="26 June 2003" version="v72">
14294 SetThreadLocalStorage and SetEnvironmentLocalStorage should allow value
14295 to be set to NULL.
14296 NotifyFramePop, GetFrameLocationm and all the local variable operations
14297 needed to have their wording about frames fixed.
14298 Grammar and clarity need to be fixed throughout.
14299 Capitalization and puntuation need to be consistent.
14300 Need micro version number and masks for accessing major, minor, and micro.
14301 The error code lists should indicate which must be returned by
14302 an implementation.
14303 The command line properties should be visible in the properties functions.
14304 Disallow popping from the current thread.
14305 Allow implementations to return opaque frame error when they cannot pop.
14306 The NativeMethodBind event should be sent during any phase.
14307 The DynamicCodeGenerated event should be sent during any phase.
14308 The following functions should be allowed to operate before VMInit:
14309 Set/GetEnvironmentLocalStorage
14310 GetMethodDeclaringClass
14311 GetClassSignature
14312 GetClassModifiers
14313 IsInterface
14314 IsArrayClass
14315 GetMethodName
14316 GetMethodModifiers
14317 GetMaxLocals
14318 GetArgumentsSize
14319 GetLineNumberTable
14320 GetMethodLocation
14321 IsMethodNative
14322 IsMethodSynthetic.
14323 Other changes (to XSL):
14324 Argument description should show asterisk after not before pointers.
14325 NotifyFramePop, GetFrameLocationm and all the local variable operations
14326 should hsve the NO_MORE_FRAMES error added.
14327 Not alive threads should have a different error return than invalid thread.
14328 </change>
14329 <change date="7 July 2003" version="v73">
14330 VerboseOutput event was missing message parameter.
14331 Minor fix-ups.
14332 </change>
14333 <change date="14 July 2003" version="v74">
14334 Technical Publications Department corrections.
14335 Allow thread and environment local storage to be set to NULL.
14336 </change>
14337 <change date="23 July 2003" version="v75">
14338 Use new Agent_OnLoad rather than overloaded JVM_OnLoad.
14339 Add JNICALL to callbacks (XSL).
14340 Document JNICALL requirement for both events and callbacks (XSL).
14341 Restrict RedefineClasses to methods and attributes.
14342 Elide the VerboseOutput event.
14343 VMObjectAlloc: restrict when event is sent and remove method parameter.
14344 Finish loose ends from Tech Pubs edit.
14345 </change>
14346 <change date="24 July 2003" version="v76">
14347 Change ClassFileLoadHook event to send the class instead of a boolean of redefine.
14348 </change>
14349 <change date="24 July 2003" version="v77">
14350 XML fixes.
14351 Minor text clarifications and corrections.
14352 </change>
14353 <change date="24 July 2003" version="v78">
14354 Remove GetExceptionHandlerTable and GetThrownExceptions from <jvmti/>.
14355 Clarify that stack frames are JVM Spec frames.
14356 Split can_get_source_info into can_get_source_file_name, can_get_line_numbers,
14357 and can_get_source_debug_extension.
14358 PopFrame cannot have a native calling method.
14359 Removed incorrect statement in GetClassloaderClasses
14360 (see <vmspec chapter="4.4"/>).
14361 </change>
14362 <change date="24 July 2003" version="v79">
14363 XML and text fixes.
14364 Move stack frame description into Stack Frame category.
14365 </change>
14366 <change date="26 July 2003" version="v80">
14367 Allow NULL (means bootstrap loader) for GetClassloaderClasses.
14368 Add new heap reference kinds for references from classes.
14369 Add timer information struct and query functions.
14370 Add AvailableProcessors.
14371 Rename GetOtherThreadCpuTime to GetThreadCpuTime.
14372 Explicitly add JVMTI_ERROR_INVALID_THREAD and JVMTI_ERROR_THREAD_NOT_ALIVE
14373 to SetEventNotification mode.
14374 Add initial thread to the VM_INIT event.
14375 Remove platform assumptions from AddToBootstrapClassLoaderSearch.
14376 </change>
14377 <change date="26 July 2003" version="v81">
14378 Grammar and clarity changes per review.
14379 </change>
14380 <change date="27 July 2003" version="v82">
14381 More grammar and clarity changes per review.
14382 Add Agent_OnUnload.
14383 </change>
14384 <change date="28 July 2003" version="v83">
14385 Change return type of Agent_OnUnload to void.
14386 </change>
14387 <change date="28 July 2003" version="v84">
14388 Rename JVMTI_REFERENCE_ARRAY to JVMTI_REFERENCE_ARRAY_ELEMENT.
14389 </change>
14390 <change date="28 July 2003" version="v85">
14391 Steal java.lang.Runtime.availableProcessors() wording for
14392 AvailableProcessors().
14393 Guarantee that zero will never be an event ID.
14394 Remove some issues which are no longer issues.
14395 Per review, rename and more completely document the timer
14396 information functions.
14397 </change>
14398 <change date="29 July 2003" version="v86">
14399 Non-spec visible change to XML controlled implementation:
14400 SetThreadLocalStorage must run in VM mode.
14401 </change>
14402 <change date="5 August 2003" version="0.1.87">
14403 Add GetErrorName.
14404 Add varargs warning to jvmtiExtensionEvent.
14405 Remove "const" on the jvmtiEnv* of jvmtiExtensionEvent.
14406 Remove unused can_get_exception_info capability.
14407 Pass jvmtiEnv* and JNIEnv* to the jvmtiStartFunction.
14408 Fix jvmtiExtensionFunctionInfo.func declared type.
14409 Extension function returns error code.
14410 Use new version numbering.
14411 </change>
14412 <change date="5 August 2003" version="0.2.88">
14413 Remove the ClassUnload event.
14414 </change>
14415 <change date="8 August 2003" version="0.2.89">
14416 Heap reference iterator callbacks return an enum that
14417 allows outgoing object references to be ignored.
14418 Allow JNIEnv as a param type to extension events/functions.
14419 </change>
14420 <change date="15 August 2003" version="0.2.90">
14421 Fix a typo.
14422 </change>
14423 <change date="2 September 2003" version="0.2.91">
14424 Remove all metadata functions: GetClassMetadata,
14425 GetFieldMetadata, and GetMethodMetadata.
14426 </change>
14427 <change date="1 October 2003" version="0.2.92">
14428 Mark the functions Allocate. Deallocate, RawMonitor*,
14429 SetEnvironmentLocalStorage, and GetEnvironmentLocalStorage
14430 as safe for use in heap callbacks and GC events.
14431 </change>
14432 <change date="24 November 2003" version="0.2.93">
14433 Add pass through opaque user data pointer to heap iterate
14434 functions and callbacks.
14435 In the CompiledMethodUnload event, send the code address.
14436 Add GarbageCollectionOccurred event.
14437 Add constant pool reference kind.
14438 Mark the functions CreateRawMonitor and DestroyRawMonitor
14439 as safe for use in heap callbacks and GC events.
14440 Clarify: VMDeath, GetCurrentThreadCpuTimerInfo,
14441 GetThreadCpuTimerInfo, IterateOverReachableObjects,
14442 IterateOverObjectsReachableFromObject, GetTime and
14443 JVMTI_ERROR_NULL_POINTER.
14444 Add missing errors to: GenerateEvents and
14445 AddToBootstrapClassLoaderSearch.
14446 Fix description of ClassFileLoadHook name parameter.
14447 In heap callbacks and GC/ObjectFree events, specify
14448 that only explicitly allowed functions can be called.
14449 Allow GetCurrentThreadCpuTimerInfo, GetCurrentThreadCpuTime,
14450 GetTimerInfo, and GetTime during callback.
14451 Allow calling SetTag/GetTag during the onload phase.
14452 SetEventNotificationMode, add: error attempted inappropriate
14453 thread level control.
14454 Remove jvmtiExceptionHandlerEntry.
14455 Fix handling of native methods on the stack --
14456 location_ptr param of GetFrameLocation, remove
14457 JVMTI_ERROR_OPAQUE_FRAME from GetFrameLocation,
14458 jvmtiFrameInfo.location, and jlocation.
14459 Remove typo (from JVMPI) implying that the MonitorWaited
14460 event is sent on sleep.
14461 </change>
14462 <change date="25 November 2003" version="0.2.94">
14463 Clarifications and typos.
14464 </change>
14465 <change date="3 December 2003" version="0.2.95">
14466 Allow NULL user_data in heap iterators.
14467 </change>
14468 <change date="28 January 2004" version="0.2.97">
14469 Add GetThreadState, deprecate GetThreadStatus.
14470 </change>
14471 <change date="29 January 2004" version="0.2.98">
14472 INVALID_SLOT and TYPE_MISMATCH errors should be optional.
14473 </change>
14474 <change date="12 February 2004" version="0.2.102">
14475 Remove MonitorContendedExit.
14476 Added JNIEnv parameter to VMObjectAlloc.
14477 Clarified definition of class_tag and referrer_index
14478 parameters to heap callbacks.
14479 </change>
14480 <change date="16 Febuary 2004" version="0.2.103">
14481 Document JAVA_TOOL_OPTIONS.
14482 </change>
14483 <change date="17 Febuary 2004" version="0.2.105">
14484 Divide start phase into primordial and start.
14485 Add VMStart event
14486 Change phase associations of functions and events.
14487 </change>
14488 <change date="18 Febuary 2004" version="0.3.6">
14489 Elide deprecated GetThreadStatus.
14490 Bump minor version, subtract 100 from micro version
14491 </change>
14492 <change date="18 Febuary 2004" version="0.3.7">
14493 Document that timer nanosecond values are unsigned.
14494 Clarify text having to do with native methods.
14495 </change>
14496 <change date="19 Febuary 2004" version="0.3.8">
14497 Fix typos.
14498 Remove elided deprecated GetThreadStatus.
14499 </change>
14500 <change date="23 Febuary 2004" version="0.3.9">
14501 Require NotifyFramePop to act on suspended threads.
14502 </change>
14503 <change date="24 Febuary 2004" version="0.3.10">
14504 Add capabilities
14505 (<internallink id="jvmtiCapabilities.can_redefine_any_class"
14506 ><code>can_redefine_any_class</code></internallink>
14507 and
14508 <internallink id="jvmtiCapabilities.can_generate_all_class_hook_events"
14509 ><code>can_generate_all_class_hook_events</code></internallink>)
14510 and an error (<errorlink id="JVMTI_ERROR_UNMODIFIABLE_CLASS"></errorlink>)
14511 which allow some classes to be unmodifiable.
14512 </change>
14513 <change date="28 Febuary 2004" version="0.3.11">
14514 Add JVMTI_ERROR_MUST_POSSESS_CAPABILITY to SetEventNotificationMode.
14515 </change>
14516 <change date="8 March 2004" version="0.3.12">
14517 Clarified CompiledMethodUnload so that it is clear the event
14518 may be posted after the class has been unloaded.
14519 </change>
14520 <change date="5 March 2004" version="0.3.13">
14521 Change the size parameter of VMObjectAlloc to jlong to match GetObjectSize.
14522 </change>
14523 <change date="13 March 2004" version="0.3.14">
14524 Added guideline for the use of the JNI FindClass function in event
14525 callback functions.
14526 </change>
14527 <change date="15 March 2004" version="0.3.15">
14528 Add GetAllStackTraces and GetThreadListStackTraces.
14529 </change>
14530 <change date="19 March 2004" version="0.3.16">
14531 ClassLoad and ClassPrepare events can be posted during start phase.
14532 </change>
14533 <change date="25 March 2004" version="0.3.17">
14534 Add JVMTI_ERROR_NATIVE_METHOD to GetLineNumberTable, GetLocalVariableTable,
14535 GetMaxLocals, GetArgumentsSize, GetMethodLocation, GetBytecodes.
14536 </change>
14537 <change date="29 March 2004" version="0.3.18">
14538 Return the timer kind in the timer information structure.
14539 </change>
14540 <change date="31 March 2004" version="0.3.19">
14541 Spec clarifications:
14542 JVMTI_THREAD_STATE_IN_NATIVE might not include JNI or <jvmti/>.
14543 ForceGarbageCollection does not run finalizers.
14544 The context of the specification is the Java platform.
14545 Warn about early instrumentation.
14546 </change>
14547 <change date="1 April 2004" version="0.3.20">
14548 Refinements to the above clarifications and
14549 Clarify that an error returned by Agent_OnLoad terminates the VM.
14550 </change>
14551 <change date="1 April 2004" version="0.3.21">
14552 Array class creation does not generate a class load event.
14553 </change>
14554 <change date="7 April 2004" version="0.3.22">
14555 Align thread state hierarchy more closely with java.lang.Thread.State.
14556 </change>
14557 <change date="12 April 2004" version="0.3.23">
14558 Clarify the documentation of thread state.
14559 </change>
14560 <change date="19 April 2004" version="0.3.24">
14561 Remove GarbageCollectionOccurred event -- can be done by agent.
14562 </change>
14563 <change date="22 April 2004" version="0.3.25">
14564 Define "command-line option".
14565 </change>
14566 <change date="29 April 2004" version="0.3.26">
14567 Describe the intended use of bytecode instrumentation.
14568 Fix description of extension event first parameter.
14569 </change>
14570 <change date="30 April 2004" version="0.3.27">
14571 Clarification and typos.
14572 </change>
14573 <change date="18 May 2004" version="0.3.28">
14574 Remove DataDumpRequest event.
14575 </change>
14576 <change date="18 May 2004" version="0.3.29">
14577 Clarify RawMonitorWait with zero timeout.
14578 Clarify thread state after RunAgentThread.
14579 </change>
14580 <change date="24 May 2004" version="0.3.30">
14581 Clean-up: fix bad/old links, etc.
14582 </change>
14583 <change date="30 May 2004" version="0.3.31">
14584 Clarifications including:
14585 All character strings are modified UTF-8.
14586 Agent thread visibiity.
14587 Meaning of obsolete method version.
14588 Thread invoking heap callbacks,
14589 </change>
14590 <change date="1 June 2004" version="1.0.32">
14591 Bump major.minor version numbers to "1.0".
14592 </change>
14593 <change date="2 June 2004" version="1.0.33">
14594 Clarify interaction between ForceGarbageCollection
14595 and ObjectFree.
14596 </change>
14597 <change date="6 June 2004" version="1.0.34">
14598 Restrict AddToBootstrapClassLoaderSearch and
14599 SetSystemProperty to the OnLoad phase only.
14600 </change>
14601 <change date="11 June 2004" version="1.0.35">
14602 Fix typo in SetTag.
14603 </change>
14604 <change date="18 June 2004" version="1.0.36">
14605 Fix trademarks.
14606 Add missing parameter in example GetThreadState usage.
14607 </change>
14608 <change date="4 August 2004" version="1.0.37">
14609 Copyright updates.
14610 </change>
14611 <change date="5 November 2004" version="1.0.38">
14612 Add missing function table layout.
14613 Add missing description of C++ member function format of functions.
14614 Clarify that name in CFLH can be NULL.
14615 Released as part of <tm>J2SE</tm> 5.0.
14616 </change>
14617 <change date="24 April 2005" version="1.1.47">
14618 Bump major.minor version numbers to "1.1".
14619 Add ForceEarlyReturn* functions.
14620 Add GetOwnedMonitorStackDepthInfo function.
14621 Add GetCurrentThread function.
14622 Add "since" version marker.
14623 Add AddToSystemClassLoaderSearch.
14624 Allow AddToBootstrapClassLoaderSearch be used in live phase.
14625 Fix historic rubbish in the descriptions of the heap_object_callback
14626 parameter of IterateOverHeap and IterateOverInstancesOfClass functions;
14627 disallow NULL for this parameter.
14628 Clarify, correct and make consistent: wording about current thread,
14629 opaque frames and insufficient number of frames in PopFrame.
14630 Consistently use "current frame" rather than "topmost".
14631 Clarify the JVMTI_ERROR_TYPE_MISMATCH errors in GetLocal* and SetLocal*
14632 by making them compatible with those in ForceEarlyReturn*.
14633 Many other clarifications and wording clean ups.
14634 </change>
14635 <change date="25 April 2005" version="1.1.48">
14636 Add GetConstantPool.
14637 Switch references to the first edition of the VM Spec, to the seconds edition.
14638 </change>
14639 <change date="26 April 2005" version="1.1.49">
14640 Clarify minor/major version order in GetConstantPool.
14641 </change>
14642 <change date="26 April 2005" version="1.1.50">
14643 Add SetNativeMethodPrefix and SetNativeMethodPrefixes.
14644 Reassign GetOwnedMonitorStackDepthInfo to position 153.
14645 Break out Class Loader Search in its own documentation category.
14646 Deal with overly long lines in XML source.
14647 </change>
14648 <change date="29 April 2005" version="1.1.51">
14649 Allow agents be started in the live phase.
14650 Added paragraph about deploying agents.
14651 </change>
14652 <change date="30 April 2005" version="1.1.52">
14653 Add specification description to SetNativeMethodPrefix(es).
14654 Better define the conditions on GetConstantPool.
14655 </change>
14656 <change date="30 April 2005" version="1.1.53">
14657 Break out the GetClassVersionNumber function from GetConstantPool.
14658 Clean-up the references to the VM Spec.
14659 </change>
14660 <change date="1 May 2005" version="1.1.54">
14661 Allow SetNativeMethodPrefix(es) in any phase.
14662 Add clarifications about the impact of redefinition on GetConstantPool.
14663 </change>
14664 <change date="2 May 2005" version="1.1.56">
14665 Various clarifications to SetNativeMethodPrefix(es).
14666 </change>
14667 <change date="2 May 2005" version="1.1.57">
14668 Add missing performance warning to the method entry event.
14669 </change>
14670 <change date="5 May 2005" version="1.1.58">
14671 Remove internal JVMDI support.
14672 </change>
14673 <change date="8 May 2005" version="1.1.59">
14674 Add <functionlink id="RetransformClasses"/>.
14675 Revamp the bytecode instrumentation documentation.
14676 Change <functionlink id="IsMethodObsolete"/> to no longer
14677 require the can_redefine_classes capability.
14678 </change>
14679 <change date="11 May 2005" version="1.1.63">
14680 Clarifications for retransformation.
14681 </change>
14682 <change date="11 May 2005" version="1.1.64">
14683 Clarifications for retransformation, per review.
14684 Lock "retransformation (in)capable" at class load enable time.
14685 </change>
14686 <change date="4 June 2005" version="1.1.67">
14687 Add new heap functionity which supports reporting primitive values,
14688 allows setting the referrer tag, and has more powerful filtering:
14689 FollowReferences, IterateThroughHeap, and their associated
14690 callbacks, structs, enums, and constants.
14691 </change>
14692 <change date="4 June 2005" version="1.1.68">
14693 Clarification.
14694 </change>
14695 <change date="6 June 2005" version="1.1.69">
14696 FollowReferences, IterateThroughHeap: Put callbacks in a struct;
14697 Add missing error codes; reduce bits in the visit control flags.
14698 </change>
14699 <change date="14 June 2005" version="1.1.70">
14700 More on new heap functionity: spec clean-up per review.
14701 </change>
14702 <change date="15 June 2005" version="1.1.71">
14703 More on new heap functionity: Rename old heap section to Heap (1.0).
14704 </change>
14705 <change date="21 June 2005" version="1.1.72">
14706 Fix typos.
14707 </change>
14708 <change date="27 June 2005" version="1.1.73">
14709 Make referrer info structure a union.
14710 </change>
14711 <change date="9 September 2005" version="1.1.74">
14712 In new heap functions:
14713 Add missing superclass reference kind.
14714 Use a single scheme for computing field indexes.
14715 Remove outdated references to struct based referrer info.
14716 </change>
14717 <change date="12 September 2005" version="1.1.75">
14718 Don't callback during FollowReferences on frivolous java.lang.Object superclass.
14719 </change>
14720 <change date="13 September 2005" version="1.1.76">
14721 In string primitive callback, length now Unicode length.
14722 In array and string primitive callbacks, value now "const".
14723 Note possible compiler impacts on setting JNI function table.
14724 </change>
14725 <change date="13 September 2005" version="1.1.77">
14726 GetClassVersionNumbers() and GetConstantPool() should return
14727 error on array or primitive class.
14728 </change>
14729 <change date="14 September 2005" version="1.1.78">
14730 Grammar fixes.
14731 </change>
14732 <change date="26 September 2005" version="1.1.79">
14733 Add IsModifiableClass query.
14734 </change>
14735 <change date="9 February 2006" version="1.1.81">
14736 Add referrer_class_tag parameter to jvmtiHeapReferenceCallback.
14737 </change>
14738 <change date="13 February 2006" version="1.1.82">
14739 Doc fixes: update can_redefine_any_class to include retransform.
14740 Clarify that exception events cover all Throwables.
14741 In GetStackTrace, no test is done for start_depth too big if start_depth is zero,
14742 Clarify fields reported in Primitive Field Callback -- static vs instance.
14743 Repair confusing names of heap types, including callback names.
14744 Require consistent usage of stack depth in the face of thread launch methods.
14745 Note incompatibility of <jvmti/> memory management with other systems.
14746 </change>
14747 <change date="14 February 2006" version="1.1.85">
14748 Fix typos and missing renames.
14749 </change>
14750 <change date="13 March 2006" version="1.1.86">
14751 Clarify that jmethodIDs and jfieldIDs can be saved.
14752 Clarify that Iterate Over Instances Of Class includes subclasses.
14753 </change>
14754 <change date="14 March 2006" version="1.1.87">
14755 Better phrasing.
14756 </change>
14757 <change date="16 March 2006" version="1.1.88">
14758 Match the referrer_index for static fields in Object Reference Callback
14759 with the Reference Implementation (and all other known implementations);
14760 that is, make it match the definition for instance fields.
14761 In GetThreadListStackTraces, add JVMTI_ERROR_INVALID_THREAD to cover
14762 an invalid thread in the list; and specify that not started threads
14763 return empty stacks.
14764 </change>
14765 <change date="17 March 2006" version="1.1.89">
14766 Typo.
14767 </change>
14768 <change date="25 March 2006" version="1.1.90">
14769 Typo.
14770 </change>
14771 <change date="6 April 2006" version="1.1.91">
14772 Remove restrictions on AddToBootstrapClassLoaderSearch and
14773 AddToSystemClassLoaderSearch.
14774 </change>
14775 <change date="1 May 2006" version="1.1.93">
14776 Changed spec to return -1 for monitor stack depth for the
14777 implementation which can not determine stack depth.
14778 </change>
14779 <change date="3 May 2006" version="1.1.94">
14780 Corrections for readability and accuracy courtesy of Alan Pratt of IBM.
14781 List the object relationships reported in FollowReferences.
14782 </change>
14783 <change date="5 May 2006" version="1.1.95">
14784 Clarify the object relationships reported in FollowReferences.
14785 </change>
14786 <change date="28 June 2006" version="1.1.98">
14787 Clarify DisposeEnvironment; add warning.
14788 Fix typos in SetLocalXXX "retrieve" => "set".
14789 Clarify that native method prefixes must remain set while used.
14790 Clarify that exactly one Agent_OnXXX is called per agent.
14791 Clarify that library loading is independent from start-up.
14792 Remove ambiguous reference to Agent_OnLoad in the Agent_OnUnload spec.
14793 </change>
14794 <change date="31 July 2006" version="1.1.99">
14795 Clarify the interaction between functions and exceptions.
14796 Clarify and give examples of field indices.
14797 Remove confusing "That is" sentence from MonitorWait and MonitorWaited events.
14798 Update links to point to Java 6.
14799 </change>
14800 <change date="6 August 2006" version="1.1.102">
14801 Add ResourceExhaustedEvent.
14802 </change>
14803 <change date="11 October 2012" version="1.2.2">
14804 Fixed the "HTTP" and "Missing Anchor" errors reported by the LinkCheck tool.
14805 </change>
14806 <change date="19 June 2013" version="1.2.3">
14807 Added support for statically linked agents.
14808 </change>
14809 <change date="13 October 2016" version="9.0.0">
14810 Support for modules:
14811 - The majorversion is 9 now
14812 - The ClassFileLoadHook events are not sent during the primordial phase anymore.
14813 - Allow CompiledMethodLoad events at start phase
14814 - Add new capabilities:
14815 - can_generate_early_vmstart
14816 - can_generate_early_class_hook_events
14817 - Add new functions:
14818 - GetAllModules
14819 - AddModuleReads, AddModuleExports, AddModuleOpens, AddModuleUses, AddModuleProvides
14820 - IsModifiableModule
14821 Clarified can_redefine_any_classes, can_retransform_any_classes and IsModifiableClass API to
14822 disallow some implementation defined classes.
14823 </change>
14824 <change date="12 February 2017" version="9.0.0">
14825 Minor update for GetCurrentThread function:
14826 - The function may return NULL in the start phase if the
14827 can_generate_early_vmstart capability is enabled.
14828 </change>
14829 <change date="7 February 2018" version="11.0.0">
14830 Minor update for new class file NestHost and NestMembers attributes:
14831 - Specify that RedefineClasses and RetransformClasses are not allowed
14832 to change the class file NestHost and NestMembers attributes.
14833 - Add new error JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED
14834 that can be returned by RedefineClasses and RetransformClasses.
14835 </change>
14836 </changehistory>
14837
14838 </specification>
14839 <!-- Keep this comment at the end of the file
14840 Local variables:
14841 mode: sgml
14842 sgml-omittag:t
14843 sgml-shorttag:t
14844 sgml-namecase-general:t
14845 sgml-general-insert-case:lower
14846 sgml-minimize-attributes:nil
14847 sgml-always-quote-attributes:t
14848 sgml-indent-step:2
14849 sgml-indent-data:t
14850 sgml-parent-document:nil
14851 sgml-exposed-tags:nil
14852 sgml-local-catalogs:nil
14853 sgml-local-ecat-files:nil
14854 End:
14855 -->