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25
26 <!DOCTYPE specification [
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356 ]>
357
358 <specification label="JVM(TM) Tool Interface"
359 majorversion="9"
360 minorversion="0"
361 microversion="0">
362 <title subtitle="Version">
363 <tm>JVM</tm> Tool Interface
364 </title>
365
366 <intro id="whatIs" label="What is the JVM Tool Interface?">
367 The <tm>JVM</tm> Tool Interface (<jvmti/>)
368 is a programming interface used by development and monitoring tools.
369 It provides both a way to inspect the state and
370 to control the execution of applications running in the
371 <tm>Java</tm> virtual machine (VM).
372 <p/>
373 <jvmti/> is intended to provide a VM interface for the full breadth of tools
374 that need access to VM state, including but not limited to: profiling,
375 debugging, monitoring, thread analysis, and coverage analysis tools.
376 <p/>
377 <jvmti/> may not be available in all implementations of the <tm>Java</tm> virtual
378 machine.
379 <p/>
380 <jvmti/> is a two-way interface.
381 A client of <jvmti/>, hereafter called an <i>agent</i>,
382 can be notified of
383 interesting occurrences through <internallink id="EventSection">events</internallink>.
384 <jvmti/>
385 can query and control the application through many
386 <internallink id="FunctionSection">functions</internallink>,
387 either in response to events or
388 independent of them.
389 <p/>
390 Agents run in the same process with and communicate directly with
391 the virtual machine executing
392 the application being examined. This communication is
393 through a native interface (<jvmti/>). The native in-process interface allows
394 maximal control with minimal intrusion on the part of a tool.
395 Typically, agents are relatively compact. They can be controlled
396 by a separate process which implements the bulk of a tool's
397 function without interfering with the target application's normal execution.
398 </intro>
399
400 <intro id="architecture" label="Architecture">
401 Tools can be written directly to <jvmti/> or indirectly
402 through higher level interfaces.
403 The Java Platform Debugger Architecture includes <jvmti/>, but also
404 contains higher-level, out-of-process debugger interfaces. The higher-level
405 interfaces are more appropriate than <jvmti/> for many tools.
406 For more information on the Java Platform Debugger Architecture,
407 see the
408 <externallink id="jpda/architecture.html">Java
409 Platform Debugger Architecture website</externallink>.
410 </intro>
411
412 <intro id="writingAgents" label="Writing Agents">
413 Agents can be written in any native language that supports C
414 language calling conventions and C or C++
415 definitions.
416 <p/>
417 The function, event, data type, and constant definitions needed for
418 using <jvmti/> are defined in the include file <code>jvmti.h</code>.
419 To use these definitions add the <tm>J2SE</tm> include directory
420 to your include path and add
421 <example>
422 #include <jvmti.h>
423 </example>
424 to your source code.
425 </intro>
426
427 <intro id="deployingAgents" label="Deploying Agents">
428 An agent is deployed in a platform specific manner but is typically the
429 platform equivalent of a dynamic library. On the <tm>Windows</tm> operating
430 system, for example, an agent library is a "Dynamic Linked Library" (DLL).
431 On the <tm>Solaris</tm> Operating Environment, an agent library is a shared
432 object (<code>.so</code> file).
433 <p/>
434
435 An agent may be started at VM startup by specifying the agent library
436 name using a <internallink id="starting">command line option</internallink>.
437 Some implementations may support a mechanism to <internallink id="onattach">
438 start agents</internallink> in the live <functionlink id="GetPhase">phase</functionlink>.
439 The details of how this is initiated are implementation specific.
440 </intro>
441
442 <intro id="entryPoint" label="Statically Linked Agents (since version 1.2.3)">
443
444 A native JVMTI Agent may be <i>statically linked</i> with the VM.
445 The manner in which the library and VM image are combined is
446 implementation-dependent.
447 An agent L whose image has been combined with the VM is defined as
448 <i>statically linked</i> if and only if the agent exports a function
449 called Agent_OnLoad_L.
450 <p/>
451 If a <i>statically linked</i> agent L exports a function called
452 Agent_OnLoad_L and a function called Agent_OnLoad, the Agent_OnLoad
453 function will be ignored.
454 If an agent L is <i>statically linked</i>, an Agent_OnLoad_L
455 function will be invoked with the same arguments and expected return
456 value as specified for the Agent_OnLoad function.
457 An agent L that is <i>statically linked</i> will prohibit an agent of
458 the same name from being loaded dynamically.
459 <p/>
460 The VM will invoke the Agent_OnUnload_L function of the agent, if such
461 a function is exported, at the same point during VM execution as it would
462 have called the dynamic entry point Agent_OnUnLoad. A statically loaded
463 agent cannot be unloaded. The Agent_OnUnload_L function will still be
464 called to do any other agent shutdown related tasks.
465 If a <i>statically linked</i> agent L exports a function called
466 Agent_OnUnLoad_L and a function called Agent_OnUnLoad, the Agent_OnUnLoad
467 function will be ignored.
468 <p/>
469 If an agent L is <i>statically linked</i>, an Agent_OnAttach_L function
470 will be invoked with the same arguments and expected return value as
471 specified for the Agent_OnAttach function.
472 If a <i>statically linked</i> agent L exports a function called
473 Agent_OnAttach_L and a function called Agent_OnAttach, the Agent_OnAttach
474 function will be ignored.
475 </intro>
476
477 <intro id="starting" label="Agent Command Line Options">
478 The term "command-line option" is used below to
479 mean options supplied in the <code>JavaVMInitArgs</code> argument
480 to the <code>JNI_CreateJavaVM</code> function of the JNI
481 Invocation API.
482 <p/>
483 One of the two following
484 command-line options is used on VM startup to
485 properly load and run agents.
486 These arguments identify the library containing
487 the agent as well as an options
488 string to be passed in at startup.
489 <dl>
490 <dt><code>-agentlib:</code><i><agent-lib-name></i><code>=</code><i><options></i></dt>
491 <dd>
492 The name following <code>-agentlib:</code> is the name of the
493 library to load. Lookup of the library, both its full name and location,
494 proceeds in a platform-specific manner.
495 Typically, the <i><agent-lib-name></i> is expanded to an
496 operating system specific file name.
497 The <i><options></i> will be passed to the agent on start-up.
498 For example, if the option
499 <code>-agentlib:foo=opt1,opt2</code> is specified, the VM will attempt to
500 load the shared library <code>foo.dll</code> from the system <code>PATH</code>
501 under <tm>Windows</tm> or <code>libfoo.so</code> from the
502 <code>LD_LIBRARY_PATH</code> under the <tm>Solaris</tm> operating
503 environment.
504 If the agent library is statically linked into the executable
505 then no actual loading takes place.
506 <p/>
507 </dd>
508 <dt><code>-agentpath:</code><i><path-to-agent></i><code>=</code><i><options></i></dt>
509 <dd>
510 The path following <code>-agentpath:</code> is the absolute path from which
511 to load the library.
512 No library name expansion will occur.
513 The <i><options></i> will be passed to the agent on start-up.
514 For example, if the option
515 <code>-agentpath:c:\myLibs\foo.dll=opt1,opt2</code> is specified, the VM will attempt to
516 load the shared library <code>c:\myLibs\foo.dll</code>. If the agent
517 library is statically linked into the executable
518 then no actual loading takes place.
519 <p/>
520 </dd>
521 </dl>
522 For a dynamic shared library agent, the start-up routine
523 <internallink id="onload"><code>Agent_OnLoad</code></internallink>
524 in the library will be invoked. If the agent library is statically linked
525 into the executable then the system will attempt to invoke the
526 <code>Agent_OnLoad_<agent-lib-name></code> entry point where
527 <agent-lib-name> is the basename of the
528 agent. In the above example <code>-agentpath:c:\myLibs\foo.dll=opt1,opt2</code>,
529 the system will attempt to find and call the <code>Agent_OnLoad_foo</code> start-up routine.
530 <p/>
531 Libraries loaded with <code>-agentlib:</code> or <code>-agentpath:</code>
532 will be searched for JNI native method implementations to facilitate the
533 use of Java programming language code in tools, as is needed for
534 <internallink id="bci">bytecode instrumentation</internallink>.
535 <p/>
536 The agent libraries will be searched after all other libraries have been
537 searched (agents wishing to override or intercept the native method
538 implementations of non-agent methods can use the
539 <eventlink id="NativeMethodBind">NativeMethodBind event</eventlink>).
540 <p/>
541 These switches do the above and nothing more - they do not change the
542 state of the VM or <jvmti/>. No command line options are needed
543 to enable <jvmti/>
544 or aspects of <jvmti/>, this is handled programmatically
545 by the use of
546 <internallink id="capability">capabilities</internallink>.
547 </intro>
548
549 <intro id="startup" label="Agent Start-Up">
550 The VM starts each agent by invoking a start-up function.
551 If the agent is started in the <code>OnLoad</code>
552 <functionlink id="GetPhase">phase</functionlink> the function
553 <internallink id="onload"><code>Agent_OnLoad</code></internallink>
554 or <internallink id="onload"><code>Agent_OnLoad_L</code></internallink>
555 for statically linked agents will be invoked.
556 If the agent is started in the live
557 <functionlink id="GetPhase">phase</functionlink> the function
558 <internallink id="onattach"><code>Agent_OnAttach</code></internallink>
559 or <internallink id="onattach"><code>Agent_OnAttach_L</code></internallink>
560 for statically linked agents will be invoked.
561 Exactly one call to a start-up function is made per agent.
562 </intro>
563
564 <intro id="onload" label="Agent Start-Up (OnLoad phase)">
565 If an agent is started during the <code>OnLoad</code> phase then its
566 agent library must export a start-up function with the following prototype:
567 <example>
568 JNIEXPORT jint JNICALL
569 Agent_OnLoad(JavaVM *vm, char *options, void *reserved)</example>
570 Or for a statically linked agent named 'L':
571 <example>
572 JNIEXPORT jint JNICALL
573 Agent_OnLoad_L(JavaVM *vm, char *options, void *reserved)</example>
574
575 The VM will start the agent by calling this function.
576 It will be called early enough in VM initialization that:
577 <ul>
578 <li><functionlink id="SetSystemProperty">system properties</functionlink>
579 may be set before they have been used in the start-up of the VM</li>
580 <li>the full set of
581 <internallink id="capability">capabilities</internallink>
582 is still available (note that capabilities that configure the VM
583 may only be available at this time--see the
584 <internallink id="capability">Capability function section</internallink>)</li>
585 <li>no bytecodes have executed</li>
586 <li>no classes have been loaded</li>
587 <li>no objects have been created</li>
588 </ul>
589 <p/>
590 The VM will call the <code>Agent_OnLoad</code> or
591 <code>Agent_OnLoad_<agent-lib-name></code> function with
592 <i><options></i> as the second argument -
593 that is, using the command-line option examples,
594 <code>"opt1,opt2"</code> will be passed to the <code>char *options</code>
595 argument of <code>Agent_OnLoad</code>.
596 The <code>options</code> argument is encoded as a
597 <internallink id="mUTF">modified UTF-8</internallink> string.
598 If <i>=<options></i> is not specified,
599 a zero length string is passed to <code>options</code>.
600 The lifespan of the <code>options</code> string is the
601 <code>Agent_OnLoad</code> or <code>Agent_OnLoad_<agent-lib-name></code>
602 call. If needed beyond this time the string or parts of the string must
603 be copied.
604 The period between when <code>Agent_OnLoad</code> is called and when it
605 returns is called the <i>OnLoad phase</i>.
606 Since the VM is not initialized during the OnLoad
607 <functionlink id="GetPhase">phase</functionlink>,
608 the set of allowed operations
609 inside <code>Agent_OnLoad</code> is restricted (see the function descriptions for the
610 functionality available at this time).
611 The agent can safely process the options and set
612 event callbacks with <functionlink id="SetEventCallbacks"></functionlink>. Once
613 the VM initialization event is received
614 (that is, the <eventlink id="VMInit">VMInit</eventlink>
615 callback is invoked), the agent
616 can complete its initialization.
617 <rationale>
618 Early startup is required so that agents can set the desired capabilities,
619 many of which must be set before the VM is initialized.
620 In JVMDI, the -Xdebug command-line option provided
621 very coarse-grain control of capabilities.
622 JVMPI implementations use various tricks to provide a single "JVMPI on" switch.
623 No reasonable command-line
624 option could provide the fine-grain of control required to balance needed capabilities vs
625 performance impact.
626 Early startup is also needed so that agents can control the execution
627 environment - modifying the file system and system properties to install
628 their functionality.
629 </rationale>
630 <p/>
631 The return value from <code>Agent_OnLoad</code> or
632 <code>Agent_OnLoad_<agent-lib-name></code> is used to indicate an error.
633 Any value other than zero indicates an error and causes termination of the VM.
634 </intro>
635
636 <intro id="onattach" label="Agent Start-Up (Live phase)">
637 A VM may support a mechanism that allows agents to be started in the VM during the live
638 <functionlink id="GetPhase">phase</functionlink>. The details of how this is supported,
639 are implementation specific. For example, a tool may use some platform specific mechanism,
640 or implementation specific API, to attach to the running VM, and request it start a given
641 agent.
642 <p/>
643 If an agent is started during the live phase then its agent library
644 must export a start-up function
645 with the following prototype:
646 <example>
647 JNIEXPORT jint JNICALL
648 Agent_OnAttach(JavaVM* vm, char *options, void *reserved)</example>
649 Or for a statically linked agent named 'L':
650 <example>
651 JNIEXPORT jint JNICALL
652 Agent_OnAttach_L(JavaVM* vm, char *options, void *reserved)</example>
653
654 <p/>
655 The VM will start the agent by calling this function.
656 It will be called in the context of a thread
657 that is attached to the VM. The first argument <i><vm></i> is the Java VM.
658 The <i><options></i> argument is the startup options provided to the agent.
659 <i><options></i> is encoded as a <internallink id="mUTF">modified UTF-8
660 </internallink> string.
661 If startup options were not provided, a zero length string is passed to
662 <code>options</code>. The lifespan of the <code>options</code> string is the
663 <code>Agent_OnAttach</code> or <code>Agent_OnAttach_<agent-lib-name></code> call.
664 If needed beyond this time the string or parts of the string must be copied.
665 <p/>
666 Note that some <internallink id="capability">capabilities</internallink>
667 may not be available in the live phase.
668 <p/>
669 The <code>Agent_OnAttach</code> or <code>Agent_OnAttach_<agent-lib-name
670 ></code> function initializes the agent and returns a value
671 to the VM to indicate if an error occurred. Any value other than zero indicates an error.
672 An error does not cause the VM to terminate. Instead the VM ignores the error, or takes
673 some implementation specific action -- for example it might print an error to standard error,
674 or record the error in a system log.
675 </intro>
676
677 <intro id="onunload" label="Agent Shutdown">
678 The library may optionally export a
679 shutdown function with the following prototype:
680 <example>
681 JNIEXPORT void JNICALL
682 Agent_OnUnload(JavaVM *vm)</example>
683 Or for a statically linked agent named 'L':
684 <example>
685 JNIEXPORT void JNICALL
686 Agent_OnUnload_L(JavaVM *vm)</example>
687
688 This function will be called by the VM when the library is about to be unloaded.
689 The library will be unloaded (unless it is statically linked into the
690 executable) and this function will be called if some platform specific
691 mechanism causes the unload (an unload mechanism is not specified in this document)
692 or the library is (in effect) unloaded by the termination of the VM whether through
693 normal termination or VM failure, including start-up failure.
694 Uncontrolled shutdown is, of couse, an exception to this rule.
695 Note the distinction between this function and the
696 <eventlink id="VMDeath">VM Death event</eventlink>: for the VM Death event
697 to be sent, the VM must have run at least to the point of initialization and a valid
698 <jvmti/> environment must exist which has set a callback for VMDeath
699 and enabled the event.
700 None of these are required for <code>Agent_OnUnload</code> or
701 <code>Agent_OnUnload_<agent-lib-name></code> and this function
702 is also called if the library is unloaded for other reasons.
703 In the case that a VM Death event is sent, it will be sent before this
704 function is called (assuming this function is called due to VM termination).
705 This function can be used to clean-up resources allocated by the agent.
706 </intro>
707
708 <intro id="tooloptions" label="JAVA_TOOL_OPTIONS">
709 Since the command-line cannot always be accessed or modified, for example in embedded VMs
710 or simply VMs launched deep within scripts, a <code>JAVA_TOOL_OPTIONS</code> variable is
711 provided so that agents may be launched in these cases.
712 <p/>
713 Platforms which support environment variables or other named strings, may support the
714 <code>JAVA_TOOL_OPTIONS</code> variable. This variable will be broken into options at white-space
715 boundaries. White-space characters include space, tab, carriage-return, new-line,
716 vertical-tab, and form-feed. Sequences of white-space characters are considered
717 equivalent to a single white-space character. No white-space is included in the options
718 unless quoted. Quoting is as follows:
719 <ul>
720 <li>All characters enclosed between a pair of single quote marks (''), except a single
721 quote, are quoted.</li>
722 <li>Double quote characters have no special meaning inside a pair of single quote marks.</li>
723 <li>All characters enclosed between a pair of double quote marks (""), except a double
724 quote, are quoted.</li>
725 <li>Single quote characters have no special meaning inside a pair of double quote marks.</li>
726 <li>A quoted part can start or end anywhere in the variable.</li>
727 <li>White-space characters have no special meaning when quoted -- they are included in
728 the option like any other character and do not mark white-space boundaries.</li>
729 <li>The pair of quote marks is not included in the option.</li>
730 </ul>
731 <code>JNI_CreateJavaVM</code> (in the JNI Invocation API) will prepend these options to the options supplied
732 in its <code>JavaVMInitArgs</code> argument. Platforms may disable this feature in cases where security is
733 a concern; for example, the Reference Implementation disables this feature on Unix systems when
734 the effective user or group ID differs from the real ID.
735 This feature is intended to support the initialization of tools -- specifically including the
736 launching of native or Java programming language agents. Multiple tools may wish to use this
737 feature, so the variable should not be overwritten, instead, options should be appended to
738 the variable. Note that since the variable is processed at the time of the JNI Invocation
739 API create VM call, options processed by a launcher (e.g., VM selection options) will not be handled.
740 </intro>
741
742 <intro id="environments" label="Environments">
743 The <jvmti/> specification supports the use of multiple simultaneous
744 <jvmti/> agents.
745 Each agent has its own <jvmti/> environment.
746 That is, the <jvmti/> state is
747 separate for each agent - changes to one environment do not affect the
748 others. The state of a <jvmti/>
749 environment includes:
750 <ul>
751 <li><functionlink id="SetEventCallbacks">the event callbacks</functionlink></li>
752 <li><functionlink id="SetEventNotificationMode">the set of events which are enabled</functionlink></li>
753 <li><internallink id="capability">the capabilities</internallink></li>
754 <li><internallink id="memory">the memory allocation/deallocation hooks</internallink></li>
755 </ul>
756 Although their <jvmti/> state
757 is separate, agents inspect and modify the shared state
758 of the VM, they also share the native environment in which they execute.
759 As such, an agent can perturb the results of other agents or cause them
760 to fail. It is the responsibility of the agent writer to specify the level
761 of compatibility with other agents. <jvmti/> implementations are not capable
762 of preventing destructive interactions between agents. Techniques to reduce
763 the likelihood of these occurrences are beyond the scope of this document.
764 <p/>
765 An agent creates a <jvmti/> environment
766 by passing a <jvmti/> version
767 as the interface ID to the JNI Invocation API function
768 <externallink id="jni/invocation.html#getenv">
769 <code>GetEnv</code></externallink>.
770 See <internallink id="jvmtiEnvAccess">Accessing <jvmti/> Functions</internallink>
771 for more details on the creation and use of
772 <jvmti/> environments.
773 Typically, <jvmti/> environments are created by calling <code>GetEnv</code> from
774 <internallink id="onload"><code>Agent_OnLoad</code></internallink>.
775 </intro>
776
777 <intro id="bci" label="Bytecode Instrumentation">
778 This interface does not include some events that one might expect in an interface with
779 profiling support. Some examples include object allocation events and full speed
780 method enter and exit events. The interface instead provides support for
781 <i>bytecode instrumentation</i>, the ability to alter the Java virtual machine
782 bytecode instructions which comprise the target program. Typically, these alterations
783 are to add "events" to the code of a method - for example, to add, at the beginning of a method,
784 a call to <code>MyProfiler.methodEntered()</code>.
785 Since the changes are purely additive, they do not modify application
786 state or behavior.
787 Because the inserted agent code is standard bytecodes, the VM can run at full speed,
788 optimizing not only the target program but also the instrumentation. If the
789 instrumentation does not involve switching from bytecode execution, no expensive
790 state transitions are needed. The result is high performance events.
791 This approach also provides complete control to the agent: instrumentation can be
792 restricted to "interesting" portions of the code (e.g., the end user's code) and
793 can be conditional. Instrumentation can run entirely in Java programming language
794 code or can call into the native agent. Instrumentation can simply maintain
795 counters or can statistically sample events.
796 <p/>
797 Instrumentation can be inserted in one of three ways:
798 <ul>
799 <li>
800 Static Instrumentation: The class file is instrumented before it
801 is loaded into the VM - for example, by creating a duplicate directory of
802 <code>*.class</code> files which have been modified to add the instrumentation.
803 This method is extremely awkward and, in general, an agent cannot know
804 the origin of the class files which will be loaded.
805 </li>
806 <li>
807 Load-Time Instrumentation: When a class file is loaded by the VM, the raw
808 bytes of the class file are sent for instrumentation to the agent.
809 The <eventlink id="ClassFileLoadHook"/>
810 event, triggered by the class load,
811 provides this functionality. This mechanism provides efficient
812 and complete access to one-time instrumentation.
813 </li>
814 <li>
815 Dynamic Instrumentation: A class which is already loaded (and possibly
816 even running) is modified. This optional feature is provided by the
817 <eventlink id="ClassFileLoadHook"/> event, triggered by calling the
818 <functionlink id="RetransformClasses"/> function.
819 Classes can be modified multiple times and can be returned to their
820 original state.
821 The mechanism allows instrumentation which changes during the
822 course of execution.
823 </li>
824 </ul>
825 <p/>
826 The class modification functionality provided in this interface
827 is intended to provide a mechanism for instrumentation
828 (the <eventlink id="ClassFileLoadHook"/> event
829 and the <functionlink id="RetransformClasses"/> function)
830 and, during development, for fix-and-continue debugging
831 (the <functionlink id="RedefineClasses"/> function).
832 <p/>
833 Care must be taken to avoid perturbing dependencies, especially when
834 instrumenting core classes. For example, an approach to getting notification
835 of every object allocation is to instrument the constructor on
836 <code>Object</code>. Assuming that the constructor is initially
837 empty, the constructor could be changed to:
838 <example>
839 public Object() {
840 MyProfiler.allocationTracker(this);
841 }
842 </example>
843 However, if this change was made using the
844 <eventlink id="ClassFileLoadHook"/>
845 event then this might impact a typical VM as follows:
846 the first created object will call the constructor causing a class load of
847 <code>MyProfiler</code>; which will then cause
848 object creation, and since <code>MyProfiler</code> isn't loaded yet,
849 infinite recursion; resulting in a stack overflow. A refinement of this
850 would be to delay invoking the tracking method until a safe time. For
851 example, <code>trackAllocations</code> could be set in the
852 handler for the <code>VMInit</code> event.
853 <example>
854 static boolean trackAllocations = false;
855
856 public Object() {
857 if (trackAllocations) {
858 MyProfiler.allocationTracker(this);
859 }
860 }
861 </example>
862 <p/>
863 The <functionlink id="SetNativeMethodPrefix"/> allows native methods
864 to be instrumented by the use of wrapper methods.
865 </intro>
866
867 <intro id="bcimodules" label="Bytecode Instrumentation of code in modules">
868 Agents can use the functions <functionlink id="AddModuleReads"/>,
869 <functionlink id="AddModuleExports"/>, <functionlink id="AddModuleOpens"/>,
870 <functionlink id="AddModuleUses"/> and <functionlink id="AddModuleProvides"/>
871 to update a module to expand the set of modules that it reads, the set of
872 packages that it exports or opens to other modules, or the services that it
873 uses and provides.
874 <p/>
875 As an aid to agents that deploy supporting classes on the search path of
876 the bootstrap class loader, or the search path of the class loader that
877 loads the main class, the Java virtual machine arranges for the module
878 of classes transformed by the <eventlink id="ClassFileLoadHook"/> event to
879 read the unnamed module of both class loaders.
880 </intro>
881
882 <intro id="mUTF" label="Modified UTF-8 String Encoding">
883 <jvmti/> uses modified UTF-8 to encode character strings.
884 This is the same encoding used by JNI.
885 Modified UTF-8 differs
886 from standard UTF-8 in the representation of supplementary characters
887 and of the null character. See the
888 <externallink id="jni/types.html#modified-utf-8-strings">
889 Modified UTF-8 Strings</externallink>
890 section of the JNI specification for details.
891 </intro>
892
893 <intro id="context" label="Specification Context">
894 Since this interface provides access to the state of applications running in the
895 Java virtual machine;
896 terminology refers to the Java platform and not the native
897 platform (unless stated otherwise). For example:
898 <ul>
899 <li>"thread" means Java programming language thread.</li>
900 <li>"stack frame" means Java virtual machine stack frame.</li>
901 <li>"class" means Java programming language class.</li>
902 <li>"heap" means Java virtual machine heap.</li>
903 <li>"monitor" means Java programming language object monitor.</li>
904 </ul>
905 <p/>
906 Sun, Sun Microsystems, the Sun logo, Java, and JVM
907 are trademarks or registered trademarks of Oracle
908 and/or its affiliates, in the U.S. and other countries.
909 </intro>
910
911
912 <functionsection label="Functions">
913 <intro id="jvmtiEnvAccess" label="Accessing Functions">
914 Native code accesses <jvmti/> features
915 by calling <jvmti/> functions.
916 Access to <jvmti/> functions is by use of an interface pointer
917 in the same manner as
918 <externallink id="jni/design.html">Java
919 Native Interface (JNI) functions</externallink> are accessed.
920 The <jvmti/> interface pointer is called the
921 <i>environment pointer</i>.
922 <p/>
923 An environment pointer is a pointer to an environment and has
924 the type <code>jvmtiEnv*</code>.
925 An environment has information about its <jvmti/> connection.
926 The first value in the environment is a pointer to the function table.
927 The function table is an array of pointers to <jvmti/> functions.
928 Every function pointer is at a predefined offset inside the
929 array.
930 <p/>
931 When used from the C language:
932 double indirection is used to access the functions;
933 the environment pointer provides context and is the first
934 parameter of each function call; for example:
935 <example>
936 jvmtiEnv *jvmti;
937 ...
938 jvmtiError err = (*jvmti)->GetLoadedClasses(jvmti, &class_count, &classes);
939 </example>
940 <p/>
941 When used from the C++ language:
942 functions are accessed as member functions of <code>jvmtiEnv</code>;
943 the environment pointer is not passed to the function call; for example:
944 <example>
945 jvmtiEnv *jvmti;
946 ...
947 jvmtiError err = jvmti->GetLoadedClasses(&class_count, &classes);
948 </example>
949 Unless otherwise stated, all examples and declarations in this
950 specification use the C language.
951 <p/>
952 A <jvmti/> environment can be obtained through the JNI Invocation API
953 <code>GetEnv</code> function:
954 <example>
955 jvmtiEnv *jvmti;
956 ...
957 (*jvm)->GetEnv(jvm, &jvmti, JVMTI_VERSION_1_0);
958 </example>
959 Each call to <code>GetEnv</code>
960 creates a new <jvmti/> connection and thus
961 a new <jvmti/> environment.
962 The <code>version</code> argument of <code>GetEnv</code> must be
963 a <jvmti/> version.
964 The returned environment may have a different version than the
965 requested version but the returned environment must be compatible.
966 <code>GetEnv</code> will return <code>JNI_EVERSION</code> if a
967 compatible version is not available, if <jvmti/> is not supported or
968 <jvmti/> is not supported in the current VM configuration.
969 Other interfaces may be added for creating <jvmti/> environments
970 in specific contexts.
971 Each environment has its own state (for example,
972 <functionlink id="SetEventNotificationMode">desired events</functionlink>,
973 <functionlink id="SetEventCallbacks">event handling functions</functionlink>, and
974 <functionlink id="AddCapabilities">capabilities</functionlink>).
975 An environment is released with
976 <functionlink id="DisposeEnvironment"></functionlink>.
977 Thus, unlike JNI which has one environment per thread, <jvmti/> environments work
978 across threads and are created dynamically.
979 </intro>
980
981 <intro id="functionReturn" label="Function Return Values">
982 <jvmti/> functions always return an
983 <internallink id="ErrorSection">error code</internallink> via the
984 <datalink id="jvmtiError"/> function return value.
985 Some functions can return additional
986 values through pointers provided by the calling function.
987 In some cases, <jvmti/> functions allocate memory that your program must
988 explicitly deallocate. This is indicated in the individual <jvmti/>
989 function descriptions. Empty lists, arrays, sequences, etc are
990 returned as <code>NULL</code>.
991 <p/>
992 In the event that the <jvmti/> function encounters
993 an error (any return value other than <code>JVMTI_ERROR_NONE</code>) the values
994 of memory referenced by argument pointers is undefined, but no memory
995 will have been allocated and no global references will have been allocated.
996 If the error occurs because of invalid input, no action will have occurred.
997 </intro>
998
999 <intro id="refs" label="Managing JNI Object References">
1000 <jvmti/> functions identify objects with JNI references
1001 (<datalink id="jobject"/> and <datalink id="jclass"/>)
1002 and their derivatives
1003 (<datalink id="jthread"/> and <datalink id="jthreadGroup"/>).
1004 References passed to
1005 <jvmti/> functions can be either global or local, but they must be
1006 strong references. All references returned by <jvmti/> functions are
1007 local references--these local references are created
1008 during the <jvmti/> call.
1009 Local references are a resource that must be managed (see the
1010 <externallink id="jni/functions.html#local-references">
1011 JNI Documentation</externallink>).
1012 When threads return from native code all local references
1013 are freed. Note that some threads, including typical
1014 agent threads, will never return from native code.
1015 A thread is ensured the ability to create sixteen local
1016 references without the need for any explicit management.
1017 For threads executing a limited number of <jvmti/> calls before
1018 returning from native code
1019 (for example, threads processing events),
1020 it may be determined that no explicit management
1021 is needed.
1022 However, long running agent threads will need explicit
1023 local reference management--usually with the JNI functions
1024 <code>PushLocalFrame</code> and <code>PopLocalFrame</code>.
1025 Conversely, to preserve references beyond the
1026 return from native code, they must be converted to global references.
1027 These rules do not apply to <datalink id="jmethodID"/> and <datalink id="jfieldID"/>
1028 as they are not <datalink id="jobject"/>s.
1029 </intro>
1030
1031 <intro id="prereqState" label="Prerequisite State for Calling Functions">
1032 Unless the function explicitly states that the agent must bring
1033 a thread or the VM to a particular state (for example, suspended),
1034 the <jvmti/> implementation is responsible for bringing the VM to a
1035 safe and consistent state for performing the function.
1036 </intro>
1037
1038 <intro id="functionsExceptions" label="Exceptions and Functions">
1039 <jvmti/> functions never throw exceptions; error conditions are
1040 communicated via the
1041 <internallink id="functionReturn">function return value</internallink>.
1042 Any existing exception state is preserved across a call to a
1043 <jvmti/> function.
1044 See the
1045 <externallink
1046 id="jni/design.html#java-exceptions"
1047 >Java Exceptions</externallink>
1048 section of the JNI specification for information on handling exceptions.
1049 </intro>
1050
1051 <category id="memory" label="Memory Management">
1052 <intro>
1053 These functions provide for the allocation and deallocation of
1054 memory used by <jvmti/> functionality and can be used to provide
1055 working memory for agents.
1056 Memory managed by <jvmti/> is not compatible with other memory
1057 allocation libraries and mechanisms.
1058 </intro>
1059
1060 <function id="Allocate" jkernel="yes" phase="any" callbacksafe="safe" impl="notrace" num="46">
1061 <synopsis>Allocate</synopsis>
1062 <description>
1063 Allocate an area of memory through the <jvmti/> allocator.
1064 The allocated
1065 memory should be freed with <functionlink id="Deallocate"></functionlink>.
1066 </description>
1067 <origin>jvmdi</origin>
1068 <capabilities>
1069 </capabilities>
1070 <parameters>
1071 <param id="size">
1072 <jlong/>
1073 <description>
1074 The number of bytes to allocate.
1075 <rationale>
1076 <code>jlong</code> is used for compatibility with JVMDI.
1077 </rationale>
1078 </description>
1079 </param>
1080 <param id="mem_ptr">
1081 <allocbuf incount="size"><uchar/></allocbuf>
1082 <description>
1083 On return, a pointer to the beginning of the allocated memory.
1084 If <code>size</code> is zero, <code>NULL</code> is returned.
1085 </description>
1086 </param>
1087 </parameters>
1088 <errors>
1089 <error id="JVMTI_ERROR_OUT_OF_MEMORY">
1090 Memory request cannot be honored.
1091 </error>
1092 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
1093 <paramlink id="size"></paramlink> is less than zero.
1094 </error>
1095 </errors>
1096 </function>
1097
1098 <function id="Deallocate" jkernel="yes" phase="any" callbacksafe="safe" impl="notrace" num="47">
1099 <synopsis>Deallocate</synopsis>
1100 <description>
1101 Deallocate <code>mem</code> using the <jvmti/> allocator.
1102 This function should
1103 be used to deallocate any memory allocated and returned
1104 by a <jvmti/> function
1105 (including memory allocated with <functionlink id="Allocate"></functionlink>).
1106 All allocated memory must be deallocated
1107 or the memory cannot be reclaimed.
1108 </description>
1109 <origin>jvmdi</origin>
1110 <capabilities>
1111 </capabilities>
1112 <parameters>
1113 <param id="mem">
1114 <outbuf>
1115 <uchar/>
1116 <nullok>the call is ignored</nullok>
1117 </outbuf>
1118 <description>
1119 A pointer to the beginning of the allocated memory.
1120 Please ignore "On return, the elements are set."
1121 <todo>keep it from generating "On return, the elements are set"</todo>
1122 </description>
1123 </param>
1124 </parameters>
1125 <errors>
1126 </errors>
1127 </function>
1128 </category>
1129
1130 <category id="threadCategory" label="Thread">
1131 <intro>
1132 </intro>
1133
1134 <function id="GetThreadState" num="17">
1135 <synopsis>Get Thread State</synopsis>
1136 <description>
1137 Get the state of a thread. The state of the thread is represented by the
1138 answers to the hierarchical set of questions below:
1139 <ul type="circle">
1140 <li><i>Alive?</i>
1141 <ul>
1142 <li>Not alive.
1143 <ul type="circle">
1144 <li><i>Why not alive?</i>
1145 <ul>
1146 <li>New.</li>
1147 <li>Terminated (<datalink
1148 id="JVMTI_THREAD_STATE_TERMINATED"><code>JVMTI_THREAD_STATE_TERMINATED</code></datalink>)</li>
1149 </ul>
1150 </li>
1151 </ul>
1152 </li>
1153 <li>Alive (<datalink
1154 id="JVMTI_THREAD_STATE_ALIVE"><code>JVMTI_THREAD_STATE_ALIVE</code></datalink>)
1155 <ul type="circle">
1156 <li><i>Suspended?</i>
1157 <ul>
1158 <li>Suspended (<datalink
1159 id="JVMTI_THREAD_STATE_SUSPENDED"><code>JVMTI_THREAD_STATE_SUSPENDED</code></datalink>)</li>
1160 <li>Not suspended</li>
1161 </ul>
1162 </li>
1163 <li><i>Interrupted?</i>
1164 <ul>
1165 <li>Interrupted (<datalink
1166 id="JVMTI_THREAD_STATE_INTERRUPTED"><code>JVMTI_THREAD_STATE_INTERRUPTED</code></datalink>)</li>
1167 <li>Not interrupted.</li>
1168 </ul>
1169 </li>
1170 <li><i>In native?</i>
1171 <ul>
1172 <li>In native code (<datalink
1173 id="JVMTI_THREAD_STATE_IN_NATIVE"><code>JVMTI_THREAD_STATE_IN_NATIVE</code></datalink>)</li>
1174 <li>In Java programming language code</li>
1175 </ul>
1176 </li>
1177 <li><i>What alive state?</i>
1178 <ul>
1179 <li>Runnable (<datalink
1180 id="JVMTI_THREAD_STATE_RUNNABLE"><code>JVMTI_THREAD_STATE_RUNNABLE</code></datalink>)</li>
1181 <li>Blocked (<datalink
1182 id="JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER"><code>JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER</code></datalink>)</li>
1183 <li>Waiting (<datalink
1184 id="JVMTI_THREAD_STATE_WAITING"><code>JVMTI_THREAD_STATE_WAITING</code></datalink>)
1185 <ul type="circle">
1186 <li><i>Timed wait?</i>
1187 <ul>
1188 <li>Indefinite (<datalink
1189 id="JVMTI_THREAD_STATE_WAITING_INDEFINITELY"><code>JVMTI_THREAD_STATE_WAITING_INDEFINITELY</code></datalink></li>
1190 <li>Timed (<datalink
1191 id="JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT"><code>JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT</code></datalink>)</li>
1192 </ul>
1193 </li>
1194 <li><i>Why waiting?</i>
1195 <ul>
1196 <li>Object.wait (<datalink
1197 id="JVMTI_THREAD_STATE_IN_OBJECT_WAIT"><code>JVMTI_THREAD_STATE_IN_OBJECT_WAIT</code></datalink>)</li>
1198 <li>LockSupport.park (<datalink
1199 id="JVMTI_THREAD_STATE_PARKED"><code>JVMTI_THREAD_STATE_PARKED</code></datalink>)</li>
1200 <li>Sleeping (<datalink
1201 id="JVMTI_THREAD_STATE_SLEEPING"><code>JVMTI_THREAD_STATE_SLEEPING</code></datalink>)</li>
1202 </ul>
1203 </li>
1204 </ul>
1205 </li>
1206 </ul>
1207 </li>
1208 </ul>
1209 </li>
1210 </ul>
1211 </li>
1212 </ul>
1213 <p/>
1214 The answers are represented by the following bit vector.
1215 <constants id="jvmtiThreadState" label="Thread State Flags" kind="bits">
1216 <constant id="JVMTI_THREAD_STATE_ALIVE" num="0x0001">
1217 Thread is alive. Zero if thread is new (not started) or terminated.
1218 </constant>
1219 <constant id="JVMTI_THREAD_STATE_TERMINATED" num="0x0002">
1220 Thread has completed execution.
1221 </constant>
1222 <constant id="JVMTI_THREAD_STATE_RUNNABLE" num="0x0004">
1223 Thread is runnable.
1224 </constant>
1225 <constant id="JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER" num="0x0400">
1226 Thread is waiting to enter a synchronization block/method or,
1227 after an <code>Object.wait()</code>, waiting to re-enter a
1228 synchronization block/method.
1229 </constant>
1230 <constant id="JVMTI_THREAD_STATE_WAITING" num="0x0080">
1231 Thread is waiting.
1232 </constant>
1233 <constant id="JVMTI_THREAD_STATE_WAITING_INDEFINITELY" num="0x0010">
1234 Thread is waiting without a timeout.
1235 For example, <code>Object.wait()</code>.
1236 </constant>
1237 <constant id="JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT" num="0x0020">
1238 Thread is waiting with a maximum time to wait specified.
1239 For example, <code>Object.wait(long)</code>.
1240 </constant>
1241 <constant id="JVMTI_THREAD_STATE_SLEEPING" num="0x0040">
1242 Thread is sleeping -- <code>Thread.sleep(long)</code>.
1243 </constant>
1244 <constant id="JVMTI_THREAD_STATE_IN_OBJECT_WAIT" num="0x0100">
1245 Thread is waiting on an object monitor -- <code>Object.wait</code>.
1246 </constant>
1247 <constant id="JVMTI_THREAD_STATE_PARKED" num="0x0200">
1248 Thread is parked, for example: <code>LockSupport.park</code>,
1249 <code>LockSupport.parkUtil</code> and <code>LockSupport.parkNanos</code>.
1250 </constant>
1251 <constant id="JVMTI_THREAD_STATE_SUSPENDED" num="0x100000">
1252 Thread suspended.
1253 <code>java.lang.Thread.suspend()</code>
1254 or a <jvmti/> suspend function
1255 (such as <functionlink id="SuspendThread"></functionlink>)
1256 has been called on the thread. If this bit
1257 is set, the other bits refer to the thread state before suspension.
1258 </constant>
1259 <constant id="JVMTI_THREAD_STATE_INTERRUPTED" num="0x200000">
1260 Thread has been interrupted.
1261 </constant>
1262 <constant id="JVMTI_THREAD_STATE_IN_NATIVE" num="0x400000">
1263 Thread is in native code--that is, a native method is running
1264 which has not called back into the VM or Java programming
1265 language code.
1266 <p/>
1267 This flag is not set when running VM compiled Java programming
1268 language code nor is it set when running VM code or
1269 VM support code. Native VM interface functions, such as JNI and
1270 <jvmti/> functions, may be implemented as VM code.
1271 </constant>
1272 <constant id="JVMTI_THREAD_STATE_VENDOR_1" num="0x10000000">
1273 Defined by VM vendor.
1274 </constant>
1275 <constant id="JVMTI_THREAD_STATE_VENDOR_2" num="0x20000000">
1276 Defined by VM vendor.
1277 </constant>
1278 <constant id="JVMTI_THREAD_STATE_VENDOR_3" num="0x40000000">
1279 Defined by VM vendor.
1280 </constant>
1281 </constants>
1282 The following definitions are used to convert <jvmti/> thread state
1283 to <code>java.lang.Thread.State</code> style states.
1284 <constants id="jvmtiJavaLangThreadState" label="java.lang.Thread.State Conversion Masks" kind="bits">
1285 <constant id="JVMTI_JAVA_LANG_THREAD_STATE_MASK"
1286 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">
1287 Mask the state with this before comparison
1288 </constant>
1289 <constant id="JVMTI_JAVA_LANG_THREAD_STATE_NEW"
1290 num="0">
1291 <code>java.lang.Thread.State.NEW</code>
1292 </constant>
1293 <constant id="JVMTI_JAVA_LANG_THREAD_STATE_TERMINATED"
1294 num="JVMTI_THREAD_STATE_TERMINATED">
1295 <code>java.lang.Thread.State.TERMINATED</code>
1296 </constant>
1297 <constant id="JVMTI_JAVA_LANG_THREAD_STATE_RUNNABLE"
1298 num="JVMTI_THREAD_STATE_ALIVE | JVMTI_THREAD_STATE_RUNNABLE">
1299 <code>java.lang.Thread.State.RUNNABLE</code>
1300 </constant>
1301 <constant id="JVMTI_JAVA_LANG_THREAD_STATE_BLOCKED"
1302 num="JVMTI_THREAD_STATE_ALIVE | JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER">
1303 <code>java.lang.Thread.State.BLOCKED</code>
1304 </constant>
1305 <constant id="JVMTI_JAVA_LANG_THREAD_STATE_WAITING"
1306 num="JVMTI_THREAD_STATE_ALIVE | JVMTI_THREAD_STATE_WAITING | JVMTI_THREAD_STATE_WAITING_INDEFINITELY">
1307 <code>java.lang.Thread.State.WAITING</code>
1308 </constant>
1309 <constant id="JVMTI_JAVA_LANG_THREAD_STATE_TIMED_WAITING"
1310 num="JVMTI_THREAD_STATE_ALIVE | JVMTI_THREAD_STATE_WAITING | JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT">
1311 <code>java.lang.Thread.State.TIMED_WAITING</code>
1312 </constant>
1313 </constants>
1314 <b>Rules</b>
1315 <p/>
1316 There can be no more than one answer to a question, although there can be no
1317 answer (because the answer is unknown, does not apply, or none of the answers is
1318 correct). An answer is set only when the enclosing answers match.
1319 That is, no more than one of
1320 <ul type="circle">
1321 <li><code>JVMTI_THREAD_STATE_RUNNABLE</code></li>
1322 <li><code>JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER</code></li>
1323 <li><code>JVMTI_THREAD_STATE_WAITING</code></li>
1324 </ul>
1325 can be set (a <tm>J2SE</tm> compliant implementation will always set
1326 one of these if <code>JVMTI_THREAD_STATE_ALIVE</code> is set).
1327 And if any of these are set, the enclosing answer
1328 <code>JVMTI_THREAD_STATE_ALIVE</code> is set.
1329 No more than one of
1330 <ul type="circle">
1331 <li><code>JVMTI_THREAD_STATE_WAITING_INDEFINITELY</code></li>
1332 <li><code>JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT</code></li>
1333 </ul>
1334 can be set (a <tm>J2SE</tm> compliant implementation will always set
1335 one of these if <code>JVMTI_THREAD_STATE_WAITING</code> is set).
1336 And if either is set, the enclosing answers
1337 <code>JVMTI_THREAD_STATE_ALIVE</code> and
1338 <code>JVMTI_THREAD_STATE_WAITING</code> are set.
1339 No more than one of
1340 <ul type="circle">
1341 <li><code>JVMTI_THREAD_STATE_IN_OBJECT_WAIT</code></li>
1342 <li><code>JVMTI_THREAD_STATE_PARKED</code></li>
1343 <li><code>JVMTI_THREAD_STATE_SLEEPING</code></li>
1344 </ul>
1345 can be set. And if any of these is set, the enclosing answers
1346 <code>JVMTI_THREAD_STATE_ALIVE</code> and
1347 <code>JVMTI_THREAD_STATE_WAITING</code> are set.
1348 Also, if <code>JVMTI_THREAD_STATE_SLEEPING</code> is set,
1349 then <code>JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT</code> is set.
1350 If a state <i>A</i> is implemented using the mechanism of
1351 state <i>B</i> then it is state <i>A</i> which
1352 is returned by this function.
1353 For example, if <code>Thread.sleep(long)</code>
1354 is implemented using <code>Object.wait(long)</code>
1355 then it is still <code>JVMTI_THREAD_STATE_SLEEPING</code>
1356 which is returned.
1357 More than one of
1358 <ul type="circle">
1359 <li><code>JVMTI_THREAD_STATE_SUSPENDED</code></li>
1360 <li><code>JVMTI_THREAD_STATE_INTERRUPTED</code></li>
1361 <li><code>JVMTI_THREAD_STATE_IN_NATIVE</code></li>
1362 </ul>
1363 can be set, but if any is set,
1364 <code>JVMTI_THREAD_STATE_ALIVE</code> is set.
1365 <p/>
1366 And finally,
1367 <code>JVMTI_THREAD_STATE_TERMINATED</code> cannot be set unless
1368 <code>JVMTI_THREAD_STATE_ALIVE</code> is not set.
1369 <p/>
1370 The thread state representation is designed for extension in future versions
1371 of the specification; thread state values should be used accordingly, that is
1372 they should not be used as ordinals.
1373 Most queries can be made by testing a single bit, if use in a switch statement is desired,
1374 the state bits should be masked with the interesting bits.
1375 All bits not defined above are reserved for future use.
1376 A VM, compliant to the current specification, must set reserved bits to zero.
1377 An agent should ignore reserved bits --
1378 they should not be assumed to be zero and thus should not be included in comparisons.
1379 <p/>
1380 <b>Examples</b>
1381 <p/>
1382 Note that the values below exclude reserved and vendor bits.
1383 <p/>
1384 The state of a thread blocked at a <code>synchronized</code>-statement would be:
1385 <example>
1386 JVMTI_THREAD_STATE_ALIVE + JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER
1387 </example>
1388 The state of a thread which hasn't started yet would be:
1389 <example>
1390 0
1391 </example>
1392 The state of a thread at a <code>Object.wait(3000)</code> would be:
1393 <example>
1394 JVMTI_THREAD_STATE_ALIVE + JVMTI_THREAD_STATE_WAITING +
1395 JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT +
1396 JVMTI_THREAD_STATE_MONITOR_WAITING
1397 </example>
1398 The state of a thread suspended while runnable would be:
1399 <example>
1400 JVMTI_THREAD_STATE_ALIVE + JVMTI_THREAD_STATE_RUNNABLE + JVMTI_THREAD_STATE_SUSPENDED
1401 </example>
1402 <p/>
1403 <b>Testing the State</b>
1404 <p/>
1405 In most cases, the thread state can be determined by testing the one bit corresponding
1406 to that question. For example, the code to test if a thread is sleeping:
1407 <example>
1408 jint state;
1409 jvmtiError err;
1410
1411 err = (*jvmti)->GetThreadState(jvmti, thread, &state);
1412 if (err == JVMTI_ERROR_NONE) {
1413 if (state & JVMTI_THREAD_STATE_SLEEPING) { ...
1414 </example>
1415 <p/>
1416 For waiting (that is, in <code>Object.wait</code>, parked, or sleeping) it would be:
1417 <example>
1418 if (state & JVMTI_THREAD_STATE_WAITING) { ...
1419 </example>
1420 For some states, more than one bit will need to be tested as is the case
1421 when testing if a thread has not yet been started:
1422 <example>
1423 if ((state & (JVMTI_THREAD_STATE_ALIVE | JVMTI_THREAD_STATE_TERMINATED)) == 0) { ...
1424 </example>
1425 To distinguish timed from untimed <code>Object.wait</code>:
1426 <example>
1427 if (state & JVMTI_THREAD_STATE_IN_OBJECT_WAIT) {
1428 if (state & JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT) {
1429 printf("in Object.wait(long timeout)\n");
1430 } else {
1431 printf("in Object.wait()\n");
1432 }
1433 }
1434 </example>
1435 <p/>
1436 <b>Relationship to <code>java.lang.Thread.State</code></b>
1437 <p/>
1438 The thread state represented by <code>java.lang.Thread.State</code>
1439 returned from <code>java.lang.Thread.getState()</code> is a subset of the
1440 information returned from this function.
1441 The corresponding <code>java.lang.Thread.State</code> can be determined
1442 by using the provided conversion masks.
1443 For example, this returns the name of the <code>java.lang.Thread.State</code> thread state:
1444 <example>
1445 err = (*jvmti)->GetThreadState(jvmti, thread, &state);
1446 abortOnError(err);
1447 switch (state & JVMTI_JAVA_LANG_THREAD_STATE_MASK) {
1448 case JVMTI_JAVA_LANG_THREAD_STATE_NEW:
1449 return "NEW";
1450 case JVMTI_JAVA_LANG_THREAD_STATE_TERMINATED:
1451 return "TERMINATED";
1452 case JVMTI_JAVA_LANG_THREAD_STATE_RUNNABLE:
1453 return "RUNNABLE";
1454 case JVMTI_JAVA_LANG_THREAD_STATE_BLOCKED:
1455 return "BLOCKED";
1456 case JVMTI_JAVA_LANG_THREAD_STATE_WAITING:
1457 return "WAITING";
1458 case JVMTI_JAVA_LANG_THREAD_STATE_TIMED_WAITING:
1459 return "TIMED_WAITING";
1460 }
1461 </example>
1462 </description>
1463 <origin>new</origin>
1464 <capabilities>
1465 </capabilities>
1466 <parameters>
1467 <param id="thread">
1468 <jthread null="current" started="maybe" impl="noconvert"/>
1469 <description>
1470 The thread to query.
1471 </description>
1472 </param>
1473 <param id="thread_state_ptr">
1474 <outptr><jint/></outptr>
1475 <description>
1476 On return, points to state flags,
1477 as defined by the <internallink id="jvmtiThreadState">Thread State Flags</internallink>.
1478 </description>
1479 </param>
1480 </parameters>
1481 <errors>
1482 </errors>
1483 </function>
1484
1485 <function id="GetCurrentThread" phase="start" num="18" since="1.1">
1486 <synopsis>Get Current Thread</synopsis>
1487 <description>
1488 Get the current thread.
1489 The current thread is the Java programming language thread which has called the function.
1490 The function may return <code>NULL</code> in the start phase if the
1491 <internallink id="jvmtiCapabilities.can_generate_early_vmstart">
1492 <code>can_generate_early_vmstart</code></internallink> capability is enabled
1493 and the <code>java.lang.Thread</code> class has not been initialized yet.
1494 <p/>
1495 Note that most <jvmti/> functions that take a thread
1496 as an argument will accept <code>NULL</code> to mean
1497 the current thread.
1498 </description>
1499 <origin>new</origin>
1500 <capabilities>
1501 </capabilities>
1502 <parameters>
1503 <param id="thread_ptr">
1504 <outptr><jthread/></outptr>
1505 <description>
1506 On return, points to the current thread, or <code>NULL</code>.
1507 </description>
1508 </param>
1509 </parameters>
1510 <errors>
1511 </errors>
1512 </function>
1513
1514 <function id="GetAllThreads" num="4">
1515 <synopsis>Get All Threads</synopsis>
1516 <description>
1517 Get all live threads.
1518 The threads are Java programming language threads;
1519 that is, threads that are attached to the VM.
1520 A thread is live if <code>java.lang.Thread.isAlive()</code>
1521 would return <code>true</code>, that is, the thread has
1522 been started and has not yet died.
1523 The universe of threads is determined by the context of the <jvmti/>
1524 environment, which typically is all threads attached to the VM.
1525 Note that this includes <jvmti/> agent threads
1526 (see <functionlink id="RunAgentThread"/>).
1527 </description>
1528 <origin>jvmdi</origin>
1529 <capabilities>
1530 </capabilities>
1531 <parameters>
1532 <param id="threads_count_ptr">
1533 <outptr><jint/></outptr>
1534 <description>
1535 On return, points to the number of running threads.
1536 </description>
1537 </param>
1538 <param id="threads_ptr">
1539 <allocbuf outcount="threads_count_ptr"><jthread/></allocbuf>
1540 <description>
1541 On return, points to an array of references, one
1542 for each running thread.
1543 </description>
1544 </param>
1545 </parameters>
1546 <errors>
1547 </errors>
1548 </function>
1549
1550 <function id="SuspendThread" num="5">
1551 <synopsis>Suspend Thread</synopsis>
1552 <description>
1553 Suspend the specified thread. If the calling thread is specified,
1554 this function will not return until some other thread calls
1555 <functionlink id="ResumeThread"></functionlink>.
1556 If the thread is currently suspended, this function
1557 does nothing and returns an error.
1558 </description>
1559 <origin>jvmdi</origin>
1560 <capabilities>
1561 <required id="can_suspend"></required>
1562 </capabilities>
1563 <parameters>
1564 <param id="thread">
1565 <jthread null="current"/>
1566 <description>
1567 The thread to suspend.
1568 </description>
1569 </param>
1570 </parameters>
1571 <errors>
1572 <error id="JVMTI_ERROR_THREAD_SUSPENDED">
1573 Thread already suspended.
1574 </error>
1575 </errors>
1576 </function>
1577
1578 <elide>
1579 <function id="SuspendAllThreads" num="101">
1580 <synopsis>Suspend All Threads</synopsis>
1581 <description>
1582 <issue>
1583 There has been no explicit call for this function, and it will
1584 thus be removed if there is no interest.
1585 </issue>
1586 Suspend all live threads except:
1587 <ul>
1588 <li>already suspended threads</li>
1589 <li>those listed in <paramlink id="except_list"></paramlink></li>
1590 <li>certain system (non application) threads, as determined
1591 by the VM implementation</li>
1592 </ul>
1593 The threads are Java programming language threads;
1594 native threads which are not attached to the VM are not
1595 Java programming language threads.
1596 A thread is live if <code>java.lang.Thread.isAlive()</code>
1597 would return <code>true</code>, that is, the thread has
1598 been started and has not yet died.
1599 The universe of threads is determined
1600 by the context of the <jvmti/>
1601 environment, which, typically, is all threads attached to the VM,
1602 except critical VM internal threads and <jvmti/> agent threads
1603 (see <functionlink id="RunAgentThread"/>).
1604 <p/>
1605 If the calling thread is specified,
1606 all other threads are suspended first then the caller thread is suspended -
1607 this function will not return until some other thread calls
1608 <functionlink id="ResumeThread"></functionlink>.
1609 <p/>
1610 The list of actually
1611 suspended threads is returned in
1612 <paramlink id="suspended_list_ptr"></paramlink>.
1613 Suspension is as defined in <functionlink id="SuspendThread"></functionlink>.
1614 <functionlink id="ResumeThreadList"></functionlink>
1615 can be used to resume the suspended threads.
1616 </description>
1617 <origin>new</origin>
1618 <capabilities>
1619 <required id="can_suspend"></required>
1620 </capabilities>
1621 <parameters>
1622 <param id="except_count">
1623 <jint min="0"/>
1624 <description>
1625 The number of threads in the list of threads not to be suspended.
1626 </description>
1627 </param>
1628 <param id="except_list">
1629 <inbuf incount="except_count">
1630 <jthread/>
1631 <nullok>not an error if <code>except_count == 0</code></nullok>
1632 </inbuf>
1633 <description>
1634 The list of threads not to be suspended.
1635 </description>
1636 </param>
1637 <param id="suspended_count_ptr">
1638 <outptr><jint/></outptr>
1639 <description>
1640 On return, points to the number of threads suspended by this call.
1641 </description>
1642 </param>
1643 <param id="suspended_list_ptr">
1644 <allocbuf outcount="suspended_count_ptr"><jthread/></allocbuf>
1645 <description>
1646 On return, points to an array of references, one
1647 for each thread suspended.
1648 </description>
1649 </param>
1650 </parameters>
1651 <errors>
1652 <error id="JVMTI_ERROR_INVALID_THREAD">
1653 A thread in <paramlink id="except_list"></paramlink> was invalid.
1654 </error>
1655 <error id="JVMTI_ERROR_NULL_POINTER">
1656 Both <paramlink id="except_list"></paramlink> was <code>NULL</code>
1657 and <paramlink id="except_count"></paramlink> was non-zero.
1658 </error>
1659 </errors>
1660 </function>
1661 </elide>
1662
1663 <function id="SuspendThreadList" num="92">
1664 <synopsis>Suspend Thread List</synopsis>
1665 <description>
1666 Suspend the <paramlink id="request_count"></paramlink>
1667 threads specified in the
1668 <paramlink id="request_list"></paramlink> array.
1669 Threads may be resumed with
1670 <functionlink id="ResumeThreadList"></functionlink> or
1671 <functionlink id="ResumeThread"></functionlink>.
1672 If the calling thread is specified in the
1673 <paramlink id="request_list"></paramlink> array, this function will
1674 not return until some other thread resumes it.
1675 Errors encountered in the suspension of a thread
1676 are returned in the <paramlink id="results"></paramlink>
1677 array, <b>not</b> in the return value of this function.
1678 Threads that are currently suspended do not change state.
1679 </description>
1680 <origin>jvmdi</origin>
1681 <capabilities>
1682 <required id="can_suspend"></required>
1683 </capabilities>
1684 <parameters>
1685 <param id="request_count">
1686 <jint min="0"/>
1687 <description>
1688 The number of threads to suspend.
1689 </description>
1690 </param>
1691 <param id="request_list">
1692 <inbuf incount="request_count"><jthread/></inbuf>
1693 <description>
1694 The list of threads to suspend.
1695 </description>
1696 </param>
1697 <param id="results">
1698 <outbuf incount="request_count"><enum>jvmtiError</enum></outbuf>
1699 <description>
1700 An agent supplied array of
1701 <paramlink id="request_count"></paramlink> elements.
1702 On return, filled with the error code for
1703 the suspend of the corresponding thread.
1704 The error code will be
1705 <errorlink id="JVMTI_ERROR_NONE"></errorlink>
1706 if the thread was suspended by this call.
1707 Possible error codes are those specified
1708 for <functionlink id="SuspendThread"></functionlink>.
1709 </description>
1710 </param>
1711 </parameters>
1712 <errors>
1713 </errors>
1714 </function>
1715
1716 <function id="ResumeThread" num="6">
1717 <synopsis>Resume Thread</synopsis>
1718 <description>
1719 Resume a suspended thread.
1720 Any threads currently suspended through
1721 a <jvmti/> suspend function (eg.
1722 <functionlink id="SuspendThread"></functionlink>)
1723 or <code>java.lang.Thread.suspend()</code>
1724 will resume execution;
1725 all other threads are unaffected.
1726 </description>
1727 <origin>jvmdi</origin>
1728 <capabilities>
1729 <required id="can_suspend"></required>
1730 </capabilities>
1731 <parameters>
1732 <param id="thread">
1733 <jthread/>
1734 <description>
1735 The thread to resume.
1736 </description>
1737 </param>
1738 </parameters>
1739 <errors>
1740 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
1741 Thread was not suspended.
1742 </error>
1743 <error id="JVMTI_ERROR_INVALID_TYPESTATE">
1744 The state of the thread has been modified, and is now inconsistent.
1745 </error>
1746 </errors>
1747 </function>
1748
1749 <function id="ResumeThreadList" num="93">
1750 <synopsis>Resume Thread List</synopsis>
1751 <description>
1752 Resume the <paramlink id="request_count"></paramlink>
1753 threads specified in the
1754 <paramlink id="request_list"></paramlink> array.
1755 Any thread suspended through
1756 a <jvmti/> suspend function (eg.
1757 <functionlink id="SuspendThreadList"></functionlink>)
1758 or <code>java.lang.Thread.suspend()</code>
1759 will resume execution.
1760 </description>
1761 <origin>jvmdi</origin>
1762 <capabilities>
1763 <required id="can_suspend"></required>
1764 </capabilities>
1765 <parameters>
1766 <param id="request_count">
1767 <jint min="0"/>
1768 <description>
1769 The number of threads to resume.
1770 </description>
1771 </param>
1772 <param id="request_list">
1773 <inbuf incount="request_count"><jthread/></inbuf>
1774 <description>
1775 The threads to resume.
1776 </description>
1777 </param>
1778 <param id="results">
1779 <outbuf incount="request_count"><enum>jvmtiError</enum></outbuf>
1780 <description>
1781 An agent supplied array of
1782 <paramlink id="request_count"></paramlink> elements.
1783 On return, filled with the error code for
1784 the resume of the corresponding thread.
1785 The error code will be
1786 <errorlink id="JVMTI_ERROR_NONE"></errorlink>
1787 if the thread was suspended by this call.
1788 Possible error codes are those specified
1789 for <functionlink id="ResumeThread"></functionlink>.
1790 </description>
1791 </param>
1792 </parameters>
1793 <errors>
1794 </errors>
1795 </function>
1796
1797 <function id="StopThread" num="7">
1798 <synopsis>Stop Thread</synopsis>
1799 <description>
1800 Send the specified asynchronous exception to the specified thread
1801 (similar to <code>java.lang.Thread.stop</code>).
1802 Normally, this function is used to kill the specified thread with an
1803 instance of the exception <code>ThreadDeath</code>.
1804 </description>
1805 <origin>jvmdi</origin>
1806 <capabilities>
1807 <required id="can_signal_thread"></required>
1808 </capabilities>
1809 <parameters>
1810 <param id="thread">
1811 <jthread/>
1812 <description>
1813 The thread to stop.
1814 </description>
1815 </param>
1816 <param id="exception">
1817 <jobject/>
1818 <description>
1819 The asynchronous exception object.
1820 </description>
1821 </param>
1822 </parameters>
1823 <errors>
1824 </errors>
1825 </function>
1826
1827 <function id="InterruptThread" num="8">
1828 <synopsis>Interrupt Thread</synopsis>
1829 <description>
1830 Interrupt the specified thread
1831 (similar to <code>java.lang.Thread.interrupt</code>).
1832 </description>
1833 <origin>jvmdi</origin>
1834 <capabilities>
1835 <required id="can_signal_thread"></required>
1836 </capabilities>
1837 <parameters>
1838 <param id="thread">
1839 <jthread impl="noconvert"/>
1840 <description>
1841 The thread to interrupt.
1842 </description>
1843 </param>
1844 </parameters>
1845 <errors>
1846 </errors>
1847 </function>
1848
1849 <function id="GetThreadInfo" num="9">
1850 <synopsis>Get Thread Info</synopsis>
1851 <typedef id="jvmtiThreadInfo" label="Thread information structure">
1852 <field id="name">
1853 <allocfieldbuf><char/></allocfieldbuf>
1854 <description>
1855 The thread name, encoded as a
1856 <internallink id="mUTF">modified UTF-8</internallink> string.
1857 </description>
1858 </field>
1859 <field id="priority">
1860 <jint/>
1861 <description>
1862 The thread priority. See the thread priority constants:
1863 <datalink id="jvmtiThreadPriority"></datalink>.
1864 </description>
1865 </field>
1866 <field id="is_daemon">
1867 <jboolean/>
1868 <description>
1869 Is this a daemon thread?
1870 </description>
1871 </field>
1872 <field id="thread_group">
1873 <jthreadGroup/>
1874 <description>
1875 The thread group to which this thread belongs.
1876 <code>NULL</code> if the thread has died.
1877 </description>
1878 </field>
1879 <field id="context_class_loader">
1880 <jobject/>
1881 <description>
1882 The context class loader associated with this thread.
1883 </description>
1884 </field>
1885 </typedef>
1886 <description>
1887 Get thread information. The fields of the <datalink id="jvmtiThreadInfo"/> structure
1888 are filled in with details of the specified thread.
1889 </description>
1890 <origin>jvmdi</origin>
1891 <capabilities>
1892 </capabilities>
1893 <parameters>
1894 <param id="thread">
1895 <jthread null="current" impl="noconvert" started="maybe"/>
1896 <description>
1897 The thread to query.
1898 </description>
1899 </param>
1900 <param id="info_ptr">
1901 <outptr><struct>jvmtiThreadInfo</struct></outptr>
1902 <description>
1903 On return, filled with information describing the specified thread.
1904 </description>
1905 </param>
1906 </parameters>
1907 <errors>
1908 </errors>
1909 </function>
1910
1911 <function id="GetOwnedMonitorInfo" num="10">
1912 <synopsis>Get Owned Monitor Info</synopsis>
1913 <description>
1914 Get information about the monitors owned by the
1915 specified thread.
1916 </description>
1917 <origin>jvmdiClone</origin>
1918 <capabilities>
1919 <required id="can_get_owned_monitor_info"></required>
1920 </capabilities>
1921 <parameters>
1922 <param id="thread">
1923 <jthread null="current"/>
1924 <description>
1925 The thread to query.
1926 </description>
1927 </param>
1928 <param id="owned_monitor_count_ptr">
1929 <outptr><jint/></outptr>
1930 <description>
1931 The number of monitors returned.
1932 </description>
1933 </param>
1934 <param id="owned_monitors_ptr">
1935 <allocbuf outcount="owned_monitor_count_ptr"><jobject/></allocbuf>
1936 <description>
1937 The array of owned monitors.
1938 </description>
1939 </param>
1940 </parameters>
1941 <errors>
1942 </errors>
1943 </function>
1944
1945 <function id="GetOwnedMonitorStackDepthInfo" num="153" since="1.1">
1946 <synopsis>Get Owned Monitor Stack Depth Info</synopsis>
1947 <typedef id="jvmtiMonitorStackDepthInfo"
1948 label="Monitor stack depth information structure">
1949 <field id="monitor">
1950 <jobject/>
1951 <description>
1952 The owned monitor.
1953 </description>
1954 </field>
1955 <field id="stack_depth">
1956 <jint/>
1957 <description>
1958 The stack depth. Corresponds to the stack depth used in the
1959 <internallink id="stack">Stack Frame functions</internallink>.
1960 That is, zero is the current frame, one is the frame which
1961 called the current frame. And it is negative one if the
1962 implementation cannot determine the stack depth (e.g., for
1963 monitors acquired by JNI <code>MonitorEnter</code>).
1964 </description>
1965 </field>
1966 </typedef>
1967 <description>
1968 Get information about the monitors owned by the
1969 specified thread and the depth of the stack frame which locked them.
1970 </description>
1971 <origin>new</origin>
1972 <capabilities>
1973 <required id="can_get_owned_monitor_stack_depth_info"></required>
1974 </capabilities>
1975 <parameters>
1976 <param id="thread">
1977 <jthread null="current"/>
1978 <description>
1979 The thread to query.
1980 </description>
1981 </param>
1982 <param id="monitor_info_count_ptr">
1983 <outptr><jint/></outptr>
1984 <description>
1985 The number of monitors returned.
1986 </description>
1987 </param>
1988 <param id="monitor_info_ptr">
1989 <allocbuf outcount="monitor_info_count_ptr">
1990 <struct>jvmtiMonitorStackDepthInfo</struct>
1991 </allocbuf>
1992 <description>
1993 The array of owned monitor depth information.
1994 </description>
1995 </param>
1996 </parameters>
1997 <errors>
1998 </errors>
1999 </function>
2000
2001 <function id="GetCurrentContendedMonitor" num="11">
2002 <synopsis>Get Current Contended Monitor</synopsis>
2003 <description>
2004 Get the object, if any, whose monitor the specified thread is waiting to
2005 enter or waiting to regain through <code>java.lang.Object.wait</code>.
2006 </description>
2007 <origin>jvmdi</origin>
2008 <capabilities>
2009 <required id="can_get_current_contended_monitor"></required>
2010 </capabilities>
2011 <parameters>
2012 <param id="thread">
2013 <jthread null="current"/>
2014 <description>
2015 The thread to query.
2016 </description>
2017 </param>
2018 <param id="monitor_ptr">
2019 <outptr><jobject/></outptr>
2020 <description>
2021 On return, filled with the current contended monitor, or
2022 NULL if there is none.
2023 </description>
2024 </param>
2025 </parameters>
2026 <errors>
2027 </errors>
2028 </function>
2029
2030 <callback id="jvmtiStartFunction">
2031 <void/>
2032 <synopsis>Agent Start Function</synopsis>
2033 <description>
2034 Agent supplied callback function.
2035 This function is the entry point for an agent thread
2036 started with
2037 <functionlink id="RunAgentThread"></functionlink>.
2038 </description>
2039 <parameters>
2040 <param id="jvmti_env">
2041 <outptr>
2042 <struct>jvmtiEnv</struct>
2043 </outptr>
2044 <description>
2045 The <jvmti/> environment.
2046 </description>
2047 </param>
2048 <param id="jni_env">
2049 <outptr>
2050 <struct>JNIEnv</struct>
2051 </outptr>
2052 <description>
2053 The JNI environment.
2054 </description>
2055 </param>
2056 <param id="arg">
2057 <outptr>
2058 <void/>
2059 </outptr>
2060 <description>
2061 The <code>arg</code> parameter passed to
2062 <functionlink id="RunAgentThread"></functionlink>.
2063 </description>
2064 </param>
2065 </parameters>
2066 </callback>
2067
2068 <function id="RunAgentThread" num="12">
2069 <synopsis>Run Agent Thread</synopsis>
2070 <description>
2071 Starts the execution of an agent thread. with the specified native function.
2072 The parameter <paramlink id="arg"></paramlink> is forwarded on to the
2073 <functionlink id="jvmtiStartFunction">start function</functionlink>
2074 (specified with <paramlink id="proc"></paramlink>) as its single argument.
2075 This function allows the creation of agent threads
2076 for handling communication with another process or for handling events
2077 without the need to load a special subclass of <code>java.lang.Thread</code> or
2078 implementer of <code>java.lang.Runnable</code>.
2079 Instead, the created thread can run entirely in native code.
2080 However, the created thread does require a newly created instance
2081 of <code>java.lang.Thread</code> (referenced by the argument <code>thread</code>) to
2082 which it will be associated.
2083 The thread object can be created with JNI calls.
2084 <p/>
2085 The following common thread priorities are provided for your convenience:
2086 <constants id="jvmtiThreadPriority" label="Thread Priority Constants" kind="const">
2087 <constant id="JVMTI_THREAD_MIN_PRIORITY" num="1">
2088 Minimum possible thread priority
2089 </constant>
2090 <constant id="JVMTI_THREAD_NORM_PRIORITY" num="5">
2091 Normal thread priority
2092 </constant>
2093 <constant id="JVMTI_THREAD_MAX_PRIORITY" num="10">
2094 Maximum possible thread priority
2095 </constant>
2096 </constants>
2097 <p/>
2098 The new thread is started as a daemon thread with the specified
2099 <paramlink id="priority"></paramlink>.
2100 If enabled, a <eventlink id="ThreadStart"/> event will be sent.
2101 <p/>
2102 Since the thread has been started, the thread will be live when this function
2103 returns, unless the thread has died immediately.
2104 <p/>
2105 The thread group of the thread is ignored -- specifically, the thread is not
2106 added to the thread group and the thread is not seen on queries of the thread
2107 group at either the Java programming language or <jvmti/> levels.
2108 <p/>
2109 The thread is not visible to Java programming language queries but is
2110 included in <jvmti/> queries (for example,
2111 <functionlink id="GetAllThreads"/> and
2112 <functionlink id="GetAllStackTraces"/>).
2113 <p/>
2114 Upon execution of <code>proc</code>, the new thread will be attached to the
2115 VM -- see the JNI documentation on
2116 <externallink id="jni/invocation.html#attaching-to-the-vm"
2117 >Attaching to the VM</externallink>.
2118 </description>
2119 <origin>jvmdiClone</origin>
2120 <capabilities>
2121 </capabilities>
2122 <parameters>
2123 <param id="thread">
2124 <jthread impl="noconvert" started="no"/>
2125 <description>
2126 The thread to run.
2127 </description>
2128 </param>
2129 <param id="proc">
2130 <ptrtype>
2131 <struct>jvmtiStartFunction</struct>
2132 </ptrtype>
2133 <description>
2134 The start function.
2135 </description>
2136 </param>
2137 <param id="arg">
2138 <inbuf>
2139 <void/>
2140 <nullok><code>NULL</code> is passed to the start function</nullok>
2141 </inbuf>
2142 <description>
2143 The argument to the start function.
2144 </description>
2145 </param>
2146 <param id="priority">
2147 <jint/>
2148 <description>
2149 The priority of the started thread. Any thread
2150 priority allowed by <code>java.lang.Thread.setPriority</code> can be used including
2151 those in <datalink id="jvmtiThreadPriority"></datalink>.
2152 </description>
2153 </param>
2154 </parameters>
2155 <errors>
2156 <error id="JVMTI_ERROR_INVALID_PRIORITY">
2157 <paramlink id="priority"/> is less than
2158 <datalink id="JVMTI_THREAD_MIN_PRIORITY"/>
2159 or greater than
2160 <datalink id="JVMTI_THREAD_MAX_PRIORITY"/>
2161 </error>
2162 </errors>
2163 </function>
2164
2165 <function id="SetThreadLocalStorage" jkernel="yes" impl="notrace" phase="start" num="103">
2166 <synopsis>Set Thread Local Storage</synopsis>
2167 <description>
2168 The VM stores a pointer value associated with each environment-thread
2169 pair. This pointer value is called <i>thread-local storage</i>.
2170 This value is <code>NULL</code> unless set with this function.
2171 Agents can allocate memory in which they store thread specific
2172 information. By setting thread-local storage it can then be
2173 accessed with
2174 <functionlink id="GetThreadLocalStorage"></functionlink>.
2175 <p/>
2176 This function is called by the agent to set the value of the <jvmti/>
2177 thread-local storage. <jvmti/> supplies to the agent a pointer-size
2178 thread-local storage that can be used to record per-thread
2179 information.
2180 </description>
2181 <origin>jvmpi</origin>
2182 <capabilities>
2183 </capabilities>
2184 <parameters>
2185 <param id="thread">
2186 <jthread null="current"/>
2187 <description>
2188 Store to this thread.
2189 </description>
2190 </param>
2191 <param id="data">
2192 <inbuf>
2193 <void/>
2194 <nullok>value is set to <code>NULL</code></nullok>
2195 </inbuf>
2196 <description>
2197 The value to be entered into the thread-local storage.
2198 </description>
2199 </param>
2200 </parameters>
2201 <errors>
2202 </errors>
2203 </function>
2204
2205 <function id="GetThreadLocalStorage" jkernel="yes" impl="innative notrace" phase="start" num="102">
2206 <synopsis>Get Thread Local Storage</synopsis>
2207 <description>
2208 Called by the agent to get the value of the <jvmti/> thread-local
2209 storage.
2210 </description>
2211 <origin>jvmpi</origin>
2212 <capabilities>
2213 </capabilities>
2214 <parameters>
2215 <param id="thread">
2216 <jthread null="current" impl="noconvert"/>
2217 <description>
2218 Retrieve from this thread.
2219 </description>
2220 </param>
2221 <param id="data_ptr">
2222 <agentbuf><void/></agentbuf>
2223 <description>
2224 Pointer through which the value of the thread local
2225 storage is returned.
2226 If thread-local storage has not been set with
2227 <functionlink id="SetThreadLocalStorage"></functionlink> the returned
2228 pointer is <code>NULL</code>.
2229 </description>
2230 </param>
2231 </parameters>
2232 <errors>
2233 </errors>
2234 </function>
2235
2236 </category>
2237
2238 <category id="thread_groups" label="Thread Group">
2239 <intro>
2240 </intro>
2241
2242 <function id="GetTopThreadGroups" num="13">
2243 <synopsis>Get Top Thread Groups</synopsis>
2244 <description>
2245 Return all top-level (parentless) thread groups in the VM.
2246 </description>
2247 <origin>jvmdi</origin>
2248 <capabilities>
2249 </capabilities>
2250 <parameters>
2251 <param id="group_count_ptr">
2252 <outptr><jint/></outptr>
2253 <description>
2254 On return, points to the number of top-level thread groups.
2255 </description>
2256 </param>
2257 <param id="groups_ptr">
2258 <allocbuf outcount="group_count_ptr"><jthreadGroup/></allocbuf>
2259 <description>
2260 On return, refers to a pointer to the top-level thread group array.
2261 </description>
2262 </param>
2263 </parameters>
2264 <errors>
2265 </errors>
2266 </function>
2267
2268 <function id="GetThreadGroupInfo" num="14">
2269 <synopsis>Get Thread Group Info</synopsis>
2270 <typedef id="jvmtiThreadGroupInfo" label="Thread group information structure">
2271 <field id="parent">
2272 <jthreadGroup/>
2273 <description>
2274 The parent thread group.
2275 </description>
2276 </field>
2277 <field id="name">
2278 <allocfieldbuf><char/></allocfieldbuf>
2279 <description>
2280 The thread group's name, encoded as a
2281 <internallink id="mUTF">modified UTF-8</internallink> string.
2282 </description>
2283 </field>
2284 <field id="max_priority">
2285 <jint/>
2286 <description>
2287 The maximum priority for this thread group.
2288 </description>
2289 </field>
2290 <field id="is_daemon">
2291 <jboolean/>
2292 <description>
2293 Is this a daemon thread group?
2294 </description>
2295 </field>
2296 </typedef>
2297 <description>
2298 Get information about the thread group. The fields of the
2299 <functionlink id="jvmtiThreadGroupInfo"></functionlink> structure
2300 are filled in with details of the specified thread group.
2301 </description>
2302 <origin>jvmdi</origin>
2303 <capabilities>
2304 </capabilities>
2305 <parameters>
2306 <param id="group">
2307 <jthreadGroup/>
2308 <description>
2309 The thread group to query.
2310 </description>
2311 </param>
2312 <param id="info_ptr">
2313 <outptr><struct>jvmtiThreadGroupInfo</struct></outptr>
2314 <description>
2315 On return, filled with information describing the specified
2316 thread group.
2317 </description>
2318 </param>
2319 </parameters>
2320 <errors>
2321 </errors>
2322 </function>
2323
2324 <function id="GetThreadGroupChildren" num="15">
2325 <synopsis>Get Thread Group Children</synopsis>
2326 <description>
2327 Get the live threads and active subgroups in this thread group.
2328 </description>
2329 <origin>jvmdi</origin>
2330 <capabilities>
2331 </capabilities>
2332 <parameters>
2333 <param id="group">
2334 <jthreadGroup/>
2335 <description>
2336 The group to query.
2337 </description>
2338 </param>
2339 <param id="thread_count_ptr">
2340 <outptr><jint/></outptr>
2341 <description>
2342 On return, points to the number of live threads in this thread group.
2343 </description>
2344 </param>
2345 <param id="threads_ptr">
2346 <allocbuf outcount="thread_count_ptr"><jthread/></allocbuf>
2347 <description>
2348 On return, points to an array of the live threads in this thread group.
2349 </description>
2350 </param>
2351 <param id="group_count_ptr">
2352 <outptr><jint/></outptr>
2353 <description>
2354 On return, points to the number of active child thread groups
2355 </description>
2356 </param>
2357 <param id="groups_ptr">
2358 <allocbuf outcount="group_count_ptr"><jthreadGroup/></allocbuf>
2359 <description>
2360 On return, points to an array of the active child thread groups.
2361 </description>
2362 </param>
2363 </parameters>
2364 <errors>
2365 </errors>
2366 </function>
2367 </category>
2368
2369 <category id="stack" label="Stack Frame">
2370 <intro>
2371 These functions provide information about the stack of a thread.
2372 Stack frames are referenced by depth.
2373 The frame at depth zero is the current frame.
2374 <p/>
2375 Stack frames are as described in
2376 <vmspec chapter="3.6"/>,
2377 That is, they correspond to method
2378 invocations (including native methods) but do not correspond to platform native or
2379 VM internal frames.
2380 <p/>
2381 A <jvmti/> implementation may use method invocations to launch a thread and
2382 the corresponding frames may be included in the stack as presented by these functions --
2383 that is, there may be frames shown
2384 deeper than <code>main()</code> and <code>run()</code>.
2385 However this presentation must be consistent across all <jvmti/> functionality which
2386 uses stack frames or stack depth.
2387 </intro>
2388
2389 <typedef id="jvmtiFrameInfo" label="Stack frame information structure">
2390 <description>
2391 Information about a stack frame is returned in this structure.
2392 </description>
2393 <field id="method">
2394 <jmethodID/>
2395 <description>
2396 The method executing in this frame.
2397 </description>
2398 </field>
2399 <field id="location">
2400 <jlocation/>
2401 <description>
2402 The index of the instruction executing in this frame.
2403 <code>-1</code> if the frame is executing a native method.
2404 </description>
2405 </field>
2406 </typedef>
2407
2408 <typedef id="jvmtiStackInfo" label="Stack information structure">
2409 <description>
2410 Information about a set of stack frames is returned in this structure.
2411 </description>
2412 <field id="thread">
2413 <jthread/>
2414 <description>
2415 On return, the thread traced.
2416 </description>
2417 </field>
2418 <field id="state">
2419 <jint/>
2420 <description>
2421 On return, the thread state. See <functionlink id="GetThreadState"></functionlink>.
2422 </description>
2423 </field>
2424 <field id="frame_buffer">
2425 <outbuf incount="max_frame_count">
2426 <struct>jvmtiFrameInfo</struct>
2427 </outbuf>
2428 <description>
2429 On return, this agent allocated buffer is filled
2430 with stack frame information.
2431 </description>
2432 </field>
2433 <field id="frame_count">
2434 <jint/>
2435 <description>
2436 On return, the number of records filled into
2437 <code>frame_buffer</code>.
2438 This will be
2439 min(<code>max_frame_count</code>, <i>stackDepth</i>).
2440 </description>
2441 </field>
2442 </typedef>
2443
2444 <function id="GetStackTrace" num="104">
2445 <synopsis>Get Stack Trace</synopsis>
2446 <description>
2447 Get information about the stack of a thread.
2448 If <paramlink id="max_frame_count"></paramlink> is less than the depth of the stack,
2449 the <paramlink id="max_frame_count"></paramlink> topmost frames are returned,
2450 otherwise the entire stack is returned.
2451 The topmost frames, those most recently invoked, are at the beginning of the returned buffer.
2452 <p/>
2453 The following example causes up to five of the topmost frames
2454 to be returned and (if there are any frames) the currently
2455 executing method name to be printed.
2456 <example>
2457 jvmtiFrameInfo frames[5];
2458 jint count;
2459 jvmtiError err;
2460
2461 err = (*jvmti)->GetStackTrace(jvmti, aThread, 0, 5,
2462 frames, &count);
2463 if (err == JVMTI_ERROR_NONE && count >= 1) {
2464 char *methodName;
2465 err = (*jvmti)->GetMethodName(jvmti, frames[0].method,
2466 &methodName, NULL, NULL);
2467 if (err == JVMTI_ERROR_NONE) {
2468 printf("Executing method: %s", methodName);
2469 }
2470 }
2471 </example>
2472 <todo>
2473 check example code.
2474 </todo>
2475 <p/>
2476 The <paramlink id="thread"></paramlink> need not be suspended
2477 to call this function.
2478 <p/>
2479 The <functionlink id="GetLineNumberTable"></functionlink>
2480 function can be used to map locations to line numbers. Note that
2481 this mapping can be done lazily.
2482 </description>
2483 <origin>jvmpi</origin>
2484 <capabilities>
2485 </capabilities>
2486 <parameters>
2487 <param id="thread">
2488 <jthread null="current"/>
2489 <description>
2490 Fetch the stack trace of this thread.
2491 </description>
2492 </param>
2493 <param id="start_depth">
2494 <jint/>
2495 <description>
2496 Begin retrieving frames at this depth.
2497 If non-negative, count from the current frame,
2498 the first frame retrieved is at depth <code>start_depth</code>.
2499 For example, if zero, start from the current frame; if one, start from the
2500 caller of the current frame; if two, start from the caller of the
2501 caller of the current frame; and so on.
2502 If negative, count from below the oldest frame,
2503 the first frame retrieved is at depth <i>stackDepth</i><code> + start_depth</code>,
2504 where <i>stackDepth</i> is the count of frames on the stack.
2505 For example, if negative one, only the oldest frame is retrieved;
2506 if negative two, start from the frame called by the oldest frame.
2507 </description>
2508 </param>
2509 <param id="max_frame_count">
2510 <jint min="0"/>
2511 <description>
2512 The maximum number of <datalink id="jvmtiFrameInfo"/> records to retrieve.
2513 </description>
2514 </param>
2515 <param id="frame_buffer">
2516 <outbuf incount="max_frame_count" outcount="count_ptr">
2517 <struct>jvmtiFrameInfo</struct>
2518 </outbuf>
2519 <description>
2520 On return, this agent allocated buffer is filled
2521 with stack frame information.
2522 </description>
2523 </param>
2524 <param id="count_ptr">
2525 <outptr><jint/></outptr>
2526 <description>
2527 On return, points to the number of records filled in.
2528 For non-negative <code>start_depth</code>, this will be
2529 min(<code>max_frame_count</code>, <i>stackDepth</i><code> - start_depth</code>).
2530 For negative <code>start_depth</code>, this will be
2531 min(<code>max_frame_count</code>, <code>-start_depth</code>).
2532 </description>
2533 </param>
2534 </parameters>
2535 <errors>
2536 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
2537 <paramlink id="start_depth"/> is positive and greater than or equal to <i>stackDepth</i>.
2538 Or <paramlink id="start_depth"/> is negative and less than <i>-stackDepth</i>.
2539 </error>
2540 </errors>
2541 </function>
2542
2543
2544 <function id="GetAllStackTraces" num="100">
2545 <synopsis>Get All Stack Traces</synopsis>
2546 <description>
2547 Get information about the stacks of all live threads
2548 (including <internallink id="RunAgentThread">agent threads</internallink>).
2549 If <paramlink id="max_frame_count"/> is less than the depth of a stack,
2550 the <paramlink id="max_frame_count"/> topmost frames are returned for that thread,
2551 otherwise the entire stack is returned.
2552 The topmost frames, those most recently invoked, are at the beginning of the returned buffer.
2553 <p/>
2554 All stacks are collected simultaneously, that is, no changes will occur to the
2555 thread state or stacks between the sampling of one thread and the next.
2556 The threads need not be suspended.
2557
2558 <example>
2559 jvmtiStackInfo *stack_info;
2560 jint thread_count;
2561 int ti;
2562 jvmtiError err;
2563
2564 err = (*jvmti)->GetAllStackTraces(jvmti, MAX_FRAMES, &stack_info, &thread_count);
2565 if (err != JVMTI_ERROR_NONE) {
2566 ...
2567 }
2568 for (ti = 0; ti < thread_count; ++ti) {
2569 jvmtiStackInfo *infop = &stack_info[ti];
2570 jthread thread = infop->thread;
2571 jint state = infop->state;
2572 jvmtiFrameInfo *frames = infop->frame_buffer;
2573 int fi;
2574
2575 myThreadAndStatePrinter(thread, state);
2576 for (fi = 0; fi < infop->frame_count; fi++) {
2577 myFramePrinter(frames[fi].method, frames[fi].location);
2578 }
2579 }
2580 /* this one Deallocate call frees all data allocated by GetAllStackTraces */
2581 err = (*jvmti)->Deallocate(jvmti, stack_info);
2582 </example>
2583 <todo>
2584 check example code.
2585 </todo>
2586
2587 </description>
2588 <origin>new</origin>
2589 <capabilities>
2590 </capabilities>
2591 <parameters>
2592 <param id="max_frame_count">
2593 <jint min="0"/>
2594 <description>
2595 The maximum number of <datalink id="jvmtiFrameInfo"/> records to retrieve per thread.
2596 </description>
2597 </param>
2598 <param id="stack_info_ptr">
2599 <allocbuf>
2600 <struct>jvmtiStackInfo</struct>
2601 </allocbuf>
2602 <description>
2603 On return, this buffer is filled
2604 with stack information for each thread.
2605 The number of <datalink id="jvmtiStackInfo"/> records is determined
2606 by <paramlink id="thread_count_ptr"/>.
2607 <p/>
2608 Note that this buffer is allocated to include the <datalink id="jvmtiFrameInfo"/>
2609 buffers pointed to by <datalink id="jvmtiStackInfo.frame_buffer"/>.
2610 These buffers must not be separately deallocated.
2611 </description>
2612 </param>
2613 <param id="thread_count_ptr">
2614 <outptr><jint/></outptr>
2615 <description>
2616 The number of threads traced.
2617 </description>
2618 </param>
2619 </parameters>
2620 <errors>
2621 </errors>
2622 </function>
2623
2624 <function id="GetThreadListStackTraces" num="101">
2625 <synopsis>Get Thread List Stack Traces</synopsis>
2626 <description>
2627 Get information about the stacks of the supplied threads.
2628 If <paramlink id="max_frame_count"/> is less than the depth of a stack,
2629 the <paramlink id="max_frame_count"/> topmost frames are returned for that thread,
2630 otherwise the entire stack is returned.
2631 The topmost frames, those most recently invoked, are at the beginning of the returned buffer.
2632 <p/>
2633 All stacks are collected simultaneously, that is, no changes will occur to the
2634 thread state or stacks between the sampling one thread and the next.
2635 The threads need not be suspended.
2636 <p/>
2637 If a thread has not yet started or terminates before the stack information is collected,
2638 a zero length stack (<datalink id="jvmtiStackInfo.frame_count"/> will be zero)
2639 will be returned and the thread <datalink id="jvmtiStackInfo.state"/> can be checked.
2640 <p/>
2641 See the example for the similar function
2642 <functionlink id="GetAllStackTraces"/>.
2643 </description>
2644 <origin>new</origin>
2645 <capabilities>
2646 </capabilities>
2647 <parameters>
2648 <param id="thread_count">
2649 <jint min="0"/>
2650 <description>
2651 The number of threads to trace.
2652 </description>
2653 </param>
2654 <param id="thread_list">
2655 <inbuf incount="thread_count"><jthread/></inbuf>
2656 <description>
2657 The list of threads to trace.
2658 </description>
2659 </param>
2660 <param id="max_frame_count">
2661 <jint min="0"/>
2662 <description>
2663 The maximum number of <datalink id="jvmtiFrameInfo"/> records to retrieve per thread.
2664 </description>
2665 </param>
2666 <param id="stack_info_ptr">
2667 <allocbuf outcount="thread_count">
2668 <struct>jvmtiStackInfo</struct>
2669 </allocbuf>
2670 <description>
2671 On return, this buffer is filled
2672 with stack information for each thread.
2673 The number of <datalink id="jvmtiStackInfo"/> records is determined
2674 by <paramlink id="thread_count"/>.
2675 <p/>
2676 Note that this buffer is allocated to include the <datalink id="jvmtiFrameInfo"/>
2677 buffers pointed to by <datalink id="jvmtiStackInfo.frame_buffer"/>.
2678 These buffers must not be separately deallocated.
2679 </description>
2680 </param>
2681 </parameters>
2682 <errors>
2683 <error id="JVMTI_ERROR_INVALID_THREAD">
2684 An element in <paramlink id="thread_list"/> is not a thread object.
2685 </error>
2686 </errors>
2687 </function>
2688
2689 <elide>
2690 <function id="AsyncGetStackTrace" num="1000">
2691 <synopsis>Get Stack Trace--Asynchronous</synopsis>
2692 <description>
2693 Get information about the entire stack of a thread (or a sub-section of it).
2694 This is the asynchronous version of <functionlink id="GetStackTrace"></functionlink>
2695 and is reentrant and safe to call
2696 from asynchronous signal handlers.
2697 The stack trace is returned only for the calling thread.
2698 <p/>
2699 The <functionlink id="GetLineNumberTable"></functionlink>
2700 function can be used to map locations to line numbers. Note that
2701 this mapping can be done lazily.
2702 </description>
2703 <origin>jvmpi</origin>
2704 <capabilities>
2705 <required id="can_get_async_stack_trace"></required>
2706 <capability id="can_show_JVM_spec_async_frames">
2707 If <code>false</code>,
2708 <paramlink id="use_java_stack"></paramlink>
2709 must be <code>false</code>.
2710 </capability>
2711 </capabilities>
2712 <parameters>
2713 <param id="use_java_stack">
2714 <jboolean/>
2715 <description>
2716 Return the stack showing <vmspec/>
2717 model of the stack;
2718 otherwise, show the internal representation of the stack with
2719 inlined and optimized methods missing. If the virtual machine
2720 is using the <i>Java Virtual Machine Specification</i> stack model
2721 internally, this flag is ignored.
2722 </description>
2723 </param>
2724 <param id="max_count">
2725 <jint min="0"/>
2726 <description>
2727 The maximum number of <datalink id="jvmtiFrameInfo"/> records to retrieve.
2728 Retrieve this many unless the stack depth is less than <code>max_count</code>.
2729 </description>
2730 </param>
2731 <param id="frame_buffer">
2732 <outbuf incount="max_count" outcount="count_ptr">
2733 <struct>jvmtiFrameInfo</struct>
2734 <nullok>this information is not returned</nullok>
2735 </outbuf>
2736 <description>
2737 The agent passes in a buffer
2738 large enough to hold <code>max_count</code> records of
2739 <datalink id="jvmtiFrameInfo"></datalink>. This buffer must be
2740 pre-allocated by the agent.
2741 </description>
2742 </param>
2743 <param id="count_ptr">
2744 <outptr><jint/></outptr>
2745 <description>
2746 On return, points to the number of records filled in..
2747 </description>
2748 </param>
2749 </parameters>
2750 <errors>
2751 <error id="JVMTI_ERROR_UNATTACHED_THREAD">
2752 The thread being used to call this function is not attached
2753 to the virtual machine. Calls must be made from attached threads.
2754 </error>
2755 </errors>
2756 </function>
2757 </elide>
2758
2759 <function id="GetFrameCount" num="16">
2760 <synopsis>Get Frame Count</synopsis>
2761 <description>
2762 Get the number of frames currently in the specified thread's call stack.
2763 <p/>
2764 If this function is called for a thread actively executing bytecodes (for example,
2765 not the current thread and not suspended), the information returned is transient.
2766 </description>
2767 <origin>jvmdi</origin>
2768 <capabilities>
2769 </capabilities>
2770 <parameters>
2771 <param id="thread">
2772 <jthread null="current"/>
2773 <description>
2774 The thread to query.
2775 </description>
2776 </param>
2777 <param id="count_ptr">
2778 <outptr><jint/></outptr>
2779 <description>
2780 On return, points to the number of frames in the call stack.
2781 </description>
2782 </param>
2783 </parameters>
2784 <errors>
2785 </errors>
2786 </function>
2787
2788 <function id="PopFrame" num="80">
2789 <synopsis>Pop Frame</synopsis>
2790 <description>
2791 Pop the current frame of <code>thread</code>'s stack.
2792 Popping a frame takes you to the previous frame.
2793 When the thread is resumed, the execution
2794 state of the thread is reset to the state
2795 immediately before the called method was invoked.
2796 That is (using <vmspec/> terminology):
2797 <ul>
2798 <li>the current frame is discarded as the previous frame becomes the current one</li>
2799 <li>the operand stack is restored--the argument values are added back
2800 and if the invoke was not <code>invokestatic</code>,
2801 <code>objectref</code> is added back as well</li>
2802 <li>the Java virtual machine PC is restored to the opcode
2803 of the invoke instruction</li>
2804 </ul>
2805 Note however, that any changes to the arguments, which
2806 occurred in the called method, remain;
2807 when execution continues, the first instruction to
2808 execute will be the invoke.
2809 <p/>
2810 Between calling <code>PopFrame</code> and resuming the
2811 thread the state of the stack is undefined.
2812 To pop frames beyond the first,
2813 these three steps must be repeated:
2814 <ul>
2815 <li>suspend the thread via an event (step, breakpoint, ...)</li>
2816 <li>call <code>PopFrame</code></li>
2817 <li>resume the thread</li>
2818 </ul>
2819 <p/>
2820 A lock acquired by calling the called method
2821 (if it is a <code>synchronized</code> method)
2822 and locks acquired by entering <code>synchronized</code>
2823 blocks within the called method are released.
2824 Note: this does not apply to native locks or
2825 <code>java.util.concurrent.locks</code> locks.
2826 <p/>
2827 Finally blocks are not executed.
2828 <p/>
2829 Changes to global state are not addressed and thus remain changed.
2830 <p/>
2831 The specified thread must be suspended (which implies it cannot be the current thread).
2832 <p/>
2833 Both the called method and calling method must be non-native Java programming
2834 language methods.
2835 <p/>
2836 No <jvmti/> events are generated by this function.
2837 </description>
2838 <origin>jvmdi</origin>
2839 <capabilities>
2840 <required id="can_pop_frame"></required>
2841 </capabilities>
2842 <parameters>
2843 <param id="thread">
2844 <jthread/>
2845 <description>
2846 The thread whose current frame is to be popped.
2847 </description>
2848 </param>
2849 </parameters>
2850 <errors>
2851 <error id="JVMTI_ERROR_OPAQUE_FRAME">
2852 Called or calling method is a native method.
2853 The implementation is unable to pop this frame.
2854 </error>
2855 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
2856 Thread was not suspended.
2857 </error>
2858 <error id="JVMTI_ERROR_NO_MORE_FRAMES">
2859 There are less than two stack frames on the call stack.
2860 </error>
2861 </errors>
2862 </function>
2863
2864 <function id="GetFrameLocation" num="19">
2865 <synopsis>Get Frame Location</synopsis>
2866 <description>
2867 <p/>
2868 For a Java programming language frame, return the location of the instruction
2869 currently executing.
2870 </description>
2871 <origin>jvmdiClone</origin>
2872 <capabilities>
2873 </capabilities>
2874 <parameters>
2875 <param id="thread">
2876 <jthread null="current" frame="frame"/>
2877 <description>
2878 The thread of the frame to query.
2879 </description>
2880 </param>
2881 <param id="depth">
2882 <jframeID thread="thread"/>
2883 <description>
2884 The depth of the frame to query.
2885 </description>
2886 </param>
2887 <param id="method_ptr">
2888 <outptr><jmethodID/></outptr>
2889 <description>
2890 On return, points to the method for the current location.
2891 </description>
2892 </param>
2893 <param id="location_ptr">
2894 <outptr><jlocation/></outptr>
2895 <description>
2896 On return, points to the index of the currently
2897 executing instruction.
2898 Is set to <code>-1</code> if the frame is executing
2899 a native method.
2900 </description>
2901 </param>
2902 </parameters>
2903 <errors>
2904 </errors>
2905 </function>
2906
2907 <function id="NotifyFramePop" num="20">
2908 <synopsis>Notify Frame Pop</synopsis>
2909 <description>
2910 When the frame that is currently at <paramlink id="depth"></paramlink>
2911 is popped from the stack, generate a
2912 <eventlink id="FramePop"></eventlink> event. See the
2913 <eventlink id="FramePop"></eventlink> event for details.
2914 Only frames corresponding to non-native Java programming language
2915 methods can receive notification.
2916 <p/>
2917 The specified thread must either be the current thread
2918 or the thread must be suspended.
2919 </description>
2920 <origin>jvmdi</origin>
2921 <capabilities>
2922 <required id="can_generate_frame_pop_events"></required>
2923 </capabilities>
2924 <parameters>
2925 <param id="thread">
2926 <jthread null="current" frame="depth"/>
2927 <description>
2928 The thread of the frame for which the frame pop event will be generated.
2929 </description>
2930 </param>
2931 <param id="depth">
2932 <jframeID thread="thread"/>
2933 <description>
2934 The depth of the frame for which the frame pop event will be generated.
2935 </description>
2936 </param>
2937 </parameters>
2938 <errors>
2939 <error id="JVMTI_ERROR_OPAQUE_FRAME">
2940 The frame at <code>depth</code> is executing a
2941 native method.
2942 </error>
2943 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
2944 Thread was not suspended and was not the current thread.
2945 </error>
2946 </errors>
2947 </function>
2948
2949 </category>
2950
2951 <category id="ForceEarlyReturn" label="Force Early Return">
2952 <intro>
2953 These functions allow an agent to force a method
2954 to return at any point during its execution.
2955 The method which will return early is referred to as the <i>called method</i>.
2956 The called method is the current method
2957 (as defined by
2958 <vmspec chapter="3.6"/>)
2959 for the specified thread at
2960 the time the function is called.
2961 <p/>
2962 The specified thread must be suspended or must be the current thread.
2963 The return occurs when execution of Java programming
2964 language code is resumed on this thread.
2965 Between calling one of these functions and resumption
2966 of thread execution, the state of the stack is undefined.
2967 <p/>
2968 No further instructions are executed in the called method.
2969 Specifically, finally blocks are not executed.
2970 Note: this can cause inconsistent states in the application.
2971 <p/>
2972 A lock acquired by calling the called method
2973 (if it is a <code>synchronized</code> method)
2974 and locks acquired by entering <code>synchronized</code>
2975 blocks within the called method are released.
2976 Note: this does not apply to native locks or
2977 <code>java.util.concurrent.locks</code> locks.
2978 <p/>
2979 Events, such as <eventlink id="MethodExit"></eventlink>,
2980 are generated as they would be in a normal return.
2981 <p/>
2982 The called method must be a non-native Java programming
2983 language method.
2984 Forcing return on a thread with only one frame on the
2985 stack causes the thread to exit when resumed.
2986 </intro>
2987
2988 <function id="ForceEarlyReturnObject" num="81" since="1.1">
2989 <synopsis>Force Early Return - Object</synopsis>
2990 <description>
2991 This function can be used to return from a method whose
2992 result type is <code>Object</code>
2993 or a subclass of <code>Object</code>.
2994 </description>
2995 <origin>new</origin>
2996 <capabilities>
2997 <required id="can_force_early_return"></required>
2998 </capabilities>
2999 <parameters>
3000 <param id="thread">
3001 <jthread null="current"/>
3002 <description>
3003 The thread whose current frame is to return early.
3004 </description>
3005 </param>
3006 <param id="value">
3007 <jobject/>
3008 <description>
3009 The return value for the called frame.
3010 An object or <code>NULL</code>.
3011 </description>
3012 </param>
3013 </parameters>
3014 <errors>
3015 <error id="JVMTI_ERROR_OPAQUE_FRAME">
3016 Attempted to return early from a frame
3017 corresponding to a native method.
3018 Or the implementation is unable to provide
3019 this functionality on this frame.
3020 </error>
3021 <error id="JVMTI_ERROR_TYPE_MISMATCH">
3022 The result type of the called method is not
3023 <code>Object</code> or a subclass of <code>Object</code>.
3024 </error>
3025 <error id="JVMTI_ERROR_TYPE_MISMATCH">
3026 The supplied <paramlink id="value"/> is not compatible with the
3027 result type of the called method.
3028 </error>
3029 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
3030 Thread was not the current thread and was not suspended.
3031 </error>
3032 <error id="JVMTI_ERROR_NO_MORE_FRAMES">
3033 There are no more frames on the call stack.
3034 </error>
3035 </errors>
3036 </function>
3037
3038 <function id="ForceEarlyReturnInt" num="82" since="1.1">
3039 <synopsis>Force Early Return - Int</synopsis>
3040 <description>
3041 This function can be used to return from a method whose
3042 result type is <code>int</code>, <code>short</code>,
3043 <code>char</code>, <code>byte</code>, or
3044 <code>boolean</code>.
3045 </description>
3046 <origin>new</origin>
3047 <capabilities>
3048 <required id="can_force_early_return"></required>
3049 </capabilities>
3050 <parameters>
3051 <param id="thread">
3052 <jthread null="current"/>
3053 <description>
3054 The thread whose current frame is to return early.
3055 </description>
3056 </param>
3057 <param id="value">
3058 <jint/>
3059 <description>
3060 The return value for the called frame.
3061 </description>
3062 </param>
3063 </parameters>
3064 <errors>
3065 <error id="JVMTI_ERROR_OPAQUE_FRAME">
3066 Attempted to return early from a frame
3067 corresponding to a native method.
3068 Or the implementation is unable to provide
3069 this functionality on this frame.
3070 </error>
3071 <error id="JVMTI_ERROR_TYPE_MISMATCH">
3072 The result type of the called method is not
3073 <code>int</code>, <code>short</code>,
3074 <code>char</code>, <code>byte</code>, or
3075 <code>boolean</code>.
3076 </error>
3077 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
3078 Thread was not the current thread and was not suspended.
3079 </error>
3080 <error id="JVMTI_ERROR_NO_MORE_FRAMES">
3081 There are no frames on the call stack.
3082 </error>
3083 </errors>
3084 </function>
3085
3086 <function id="ForceEarlyReturnLong" num="83" since="1.1">
3087 <synopsis>Force Early Return - Long</synopsis>
3088 <description>
3089 This function can be used to return from a method whose
3090 result type is <code>long</code>.
3091 </description>
3092 <origin>new</origin>
3093 <capabilities>
3094 <required id="can_force_early_return"></required>
3095 </capabilities>
3096 <parameters>
3097 <param id="thread">
3098 <jthread null="current"/>
3099 <description>
3100 The thread whose current frame is to return early.
3101 </description>
3102 </param>
3103 <param id="value">
3104 <jlong/>
3105 <description>
3106 The return value for the called frame.
3107 </description>
3108 </param>
3109 </parameters>
3110 <errors>
3111 <error id="JVMTI_ERROR_OPAQUE_FRAME">
3112 Attempted to return early from a frame
3113 corresponding to a native method.
3114 Or the implementation is unable to provide
3115 this functionality on this frame.
3116 </error>
3117 <error id="JVMTI_ERROR_TYPE_MISMATCH">
3118 The result type of the called method is not <code>long</code>.
3119 </error>
3120 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
3121 Thread was not the current thread and was not suspended.
3122 </error>
3123 <error id="JVMTI_ERROR_NO_MORE_FRAMES">
3124 There are no frames on the call stack.
3125 </error>
3126 </errors>
3127 </function>
3128
3129 <function id="ForceEarlyReturnFloat" num="84" since="1.1">
3130 <synopsis>Force Early Return - Float</synopsis>
3131 <description>
3132 This function can be used to return from a method whose
3133 result type is <code>float</code>.
3134 </description>
3135 <origin>new</origin>
3136 <capabilities>
3137 <required id="can_force_early_return"></required>
3138 </capabilities>
3139 <parameters>
3140 <param id="thread">
3141 <jthread null="current"/>
3142 <description>
3143 The thread whose current frame is to return early.
3144 </description>
3145 </param>
3146 <param id="value">
3147 <jfloat/>
3148 <description>
3149 The return value for the called frame.
3150 </description>
3151 </param>
3152 </parameters>
3153 <errors>
3154 <error id="JVMTI_ERROR_OPAQUE_FRAME">
3155 Attempted to return early from a frame
3156 corresponding to a native method.
3157 Or the implementation is unable to provide
3158 this functionality on this frame.
3159 </error>
3160 <error id="JVMTI_ERROR_TYPE_MISMATCH">
3161 The result type of the called method is not <code>float</code>.
3162 </error>
3163 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
3164 Thread was not the current thread and was not suspended.
3165 </error>
3166 <error id="JVMTI_ERROR_NO_MORE_FRAMES">
3167 There are no frames on the call stack.
3168 </error>
3169 </errors>
3170 </function>
3171
3172 <function id="ForceEarlyReturnDouble" num="85" since="1.1">
3173 <synopsis>Force Early Return - Double</synopsis>
3174 <description>
3175 This function can be used to return from a method whose
3176 result type is <code>double</code>.
3177 </description>
3178 <origin>new</origin>
3179 <capabilities>
3180 <required id="can_force_early_return"></required>
3181 </capabilities>
3182 <parameters>
3183 <param id="thread">
3184 <jthread null="current"/>
3185 <description>
3186 The thread whose current frame is to return early.
3187 </description>
3188 </param>
3189 <param id="value">
3190 <jdouble/>
3191 <description>
3192 The return value for the called frame.
3193 </description>
3194 </param>
3195 </parameters>
3196 <errors>
3197 <error id="JVMTI_ERROR_OPAQUE_FRAME">
3198 Attempted to return early from a frame corresponding to a native method.
3199 Or the implementation is unable to provide this functionality on this frame.
3200 </error>
3201 <error id="JVMTI_ERROR_TYPE_MISMATCH">
3202 The result type of the called method is not <code>double</code>.
3203 </error>
3204 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
3205 Thread was not the current thread and was not suspended.
3206 </error>
3207 <error id="JVMTI_ERROR_NO_MORE_FRAMES">
3208 There are no frames on the call stack.
3209 </error>
3210 </errors>
3211 </function>
3212
3213 <function id="ForceEarlyReturnVoid" num="86" since="1.1">
3214 <synopsis>Force Early Return - Void</synopsis>
3215 <description>
3216 This function can be used to return from a method with no result type.
3217 That is, the called method must be declared <code>void</code>.
3218 </description>
3219 <origin>new</origin>
3220 <capabilities>
3221 <required id="can_force_early_return"></required>
3222 </capabilities>
3223 <parameters>
3224 <param id="thread">
3225 <jthread null="current"/>
3226 <description>
3227 The thread whose current frame is to return early.
3228 </description>
3229 </param>
3230 </parameters>
3231 <errors>
3232 <error id="JVMTI_ERROR_OPAQUE_FRAME">
3233 Attempted to return early from a frame
3234 corresponding to a native method.
3235 Or the implementation is unable to provide
3236 this functionality on this frame.
3237 </error>
3238 <error id="JVMTI_ERROR_TYPE_MISMATCH">
3239 The called method has a result type.
3240 </error>
3241 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
3242 Thread was not the current thread and was not suspended.
3243 </error>
3244 <error id="JVMTI_ERROR_NO_MORE_FRAMES">
3245 There are no frames on the call stack.
3246 </error>
3247 </errors>
3248 </function>
3249
3250 </category>
3251
3252 <category id="Heap" label="Heap">
3253 <intro>
3254 These functions are used to analyze the heap.
3255 Functionality includes the ability to view the objects in the
3256 heap and to tag these objects.
3257 </intro>
3258
3259 <intro id="objectTags" label="Object Tags">
3260 A <i>tag</i> is a value associated with an object.
3261 Tags are explicitly set by the agent using the
3262 <functionlink id="SetTag"></functionlink> function or by
3263 callback functions such as <functionlink id="jvmtiHeapIterationCallback"/>.
3264 <p/>
3265 Tags are local to the environment; that is, the tags of one
3266 environment are not visible in another.
3267 <p/>
3268 Tags are <code>jlong</code> values which can be used
3269 simply to mark an object or to store a pointer to more detailed
3270 information. Objects which have not been tagged have a
3271 tag of zero.
3272 Setting a tag to zero makes the object untagged.
3273 </intro>
3274
3275 <intro id="heapCallbacks" label="Heap Callback Functions">
3276 Heap functions which iterate through the heap and recursively
3277 follow object references use agent supplied callback functions
3278 to deliver the information.
3279 <p/>
3280 These heap callback functions must adhere to the following restrictions --
3281 These callbacks must not use JNI functions.
3282 These callbacks must not use <jvmti/> functions except
3283 <i>callback safe</i> functions which
3284 specifically allow such use (see the raw monitor, memory management,
3285 and environment local storage functions).
3286 <p/>
3287 An implementation may invoke a callback on an internal thread or
3288 the thread which called the iteration function.
3289 Heap callbacks are single threaded -- no more than one callback will
3290 be invoked at a time.
3291 <p/>
3292 The Heap Filter Flags can be used to prevent reporting
3293 based on the tag status of an object or its class.
3294 If no flags are set (the <code>jint</code> is zero), objects
3295 will not be filtered out.
3296
3297 <constants id="jvmtiHeapFilter" label="Heap Filter Flags" kind="bits">
3298 <constant id="JVMTI_HEAP_FILTER_TAGGED" num="0x4">
3299 Filter out tagged objects. Objects which are tagged are not included.
3300 </constant>
3301 <constant id="JVMTI_HEAP_FILTER_UNTAGGED" num="0x8">
3302 Filter out untagged objects. Objects which are not tagged are not included.
3303 </constant>
3304 <constant id="JVMTI_HEAP_FILTER_CLASS_TAGGED" num="0x10">
3305 Filter out objects with tagged classes. Objects whose class is tagged are not included.
3306 </constant>
3307 <constant id="JVMTI_HEAP_FILTER_CLASS_UNTAGGED" num="0x20">
3308 Filter out objects with untagged classes. Objects whose class is not tagged are not included.
3309 </constant>
3310 </constants>
3311
3312 <p/>
3313 The Heap Visit Control Flags are returned by the heap callbacks
3314 and can be used to abort the iteration. For the
3315 <functionlink id="jvmtiHeapReferenceCallback">Heap
3316 Reference Callback</functionlink>, it can also be used
3317 to prune the graph of traversed references
3318 (<code>JVMTI_VISIT_OBJECTS</code> is not set).
3319
3320 <constants id="jvmtiHeapVisitControl"
3321 label="Heap Visit Control Flags"
3322 kind="bits"
3323 since="1.1">
3324 <constant id="JVMTI_VISIT_OBJECTS" num="0x100">
3325 If we are visiting an object and if this callback
3326 was initiated by <functionlink id="FollowReferences"/>,
3327 traverse the references of this object.
3328 Otherwise ignored.
3329 </constant>
3330 <constant id="JVMTI_VISIT_ABORT" num="0x8000">
3331 Abort the iteration. Ignore all other bits.
3332 </constant>
3333 </constants>
3334
3335 <p/>
3336 The Heap Reference Enumeration is provided by the
3337 <functionlink id="jvmtiHeapReferenceCallback">Heap
3338 Reference Callback</functionlink> and
3339 <functionlink id="jvmtiPrimitiveFieldCallback">Primitive Field
3340 Callback</functionlink> to
3341 describe the kind of reference
3342 being reported.
3343
3344 <constants id="jvmtiHeapReferenceKind"
3345 label="Heap Reference Enumeration"
3346 kind="enum"
3347 since="1.1">
3348 <constant id="JVMTI_HEAP_REFERENCE_CLASS" num="1">
3349 Reference from an object to its class.
3350 </constant>
3351 <constant id="JVMTI_HEAP_REFERENCE_FIELD" num="2">
3352 Reference from an object to the value of one of its instance fields.
3353 </constant>
3354 <constant id="JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT" num="3">
3355 Reference from an array to one of its elements.
3356 </constant>
3357 <constant id="JVMTI_HEAP_REFERENCE_CLASS_LOADER" num="4">
3358 Reference from a class to its class loader.
3359 </constant>
3360 <constant id="JVMTI_HEAP_REFERENCE_SIGNERS" num="5">
3361 Reference from a class to its signers array.
3362 </constant>
3363 <constant id="JVMTI_HEAP_REFERENCE_PROTECTION_DOMAIN" num="6">
3364 Reference from a class to its protection domain.
3365 </constant>
3366 <constant id="JVMTI_HEAP_REFERENCE_INTERFACE" num="7">
3367 Reference from a class to one of its interfaces.
3368 Note: interfaces are defined via a constant pool reference,
3369 so the referenced interfaces may also be reported with a
3370 <code>JVMTI_HEAP_REFERENCE_CONSTANT_POOL</code> reference kind.
3371 </constant>
3372 <constant id="JVMTI_HEAP_REFERENCE_STATIC_FIELD" num="8">
3373 Reference from a class to the value of one of its static fields.
3374 </constant>
3375 <constant id="JVMTI_HEAP_REFERENCE_CONSTANT_POOL" num="9">
3376 Reference from a class to a resolved entry in the constant pool.
3377 </constant>
3378 <constant id="JVMTI_HEAP_REFERENCE_SUPERCLASS" num="10">
3379 Reference from a class to its superclass.
3380 A callback is not sent if the superclass is <code>java.lang.Object</code>.
3381 Note: loaded classes define superclasses via a constant pool
3382 reference, so the referenced superclass may also be reported with
3383 a <code>JVMTI_HEAP_REFERENCE_CONSTANT_POOL</code> reference kind.
3384 </constant>
3385 <constant id="JVMTI_HEAP_REFERENCE_JNI_GLOBAL" num="21">
3386 Heap root reference: JNI global reference.
3387 </constant>
3388 <constant id="JVMTI_HEAP_REFERENCE_SYSTEM_CLASS" num="22">
3389 Heap root reference: System class.
3390 </constant>
3391 <constant id="JVMTI_HEAP_REFERENCE_MONITOR" num="23">
3392 Heap root reference: monitor.
3393 </constant>
3394 <constant id="JVMTI_HEAP_REFERENCE_STACK_LOCAL" num="24">
3395 Heap root reference: local variable on the stack.
3396 </constant>
3397 <constant id="JVMTI_HEAP_REFERENCE_JNI_LOCAL" num="25">
3398 Heap root reference: JNI local reference.
3399 </constant>
3400 <constant id="JVMTI_HEAP_REFERENCE_THREAD" num="26">
3401 Heap root reference: Thread.
3402 </constant>
3403 <constant id="JVMTI_HEAP_REFERENCE_OTHER" num="27">
3404 Heap root reference: other heap root reference.
3405 </constant>
3406 </constants>
3407
3408 <p/>
3409 Definitions for the single character type descriptors of
3410 primitive types.
3411
3412 <constants id="jvmtiPrimitiveType"
3413 label="Primitive Type Enumeration"
3414 kind="enum"
3415 since="1.1">
3416 <constant id="JVMTI_PRIMITIVE_TYPE_BOOLEAN" num="90">
3417 'Z' - Java programming language <code>boolean</code> - JNI <code>jboolean</code>
3418 </constant>
3419 <constant id="JVMTI_PRIMITIVE_TYPE_BYTE" num="66">
3420 'B' - Java programming language <code>byte</code> - JNI <code>jbyte</code>
3421 </constant>
3422 <constant id="JVMTI_PRIMITIVE_TYPE_CHAR" num="67">
3423 'C' - Java programming language <code>char</code> - JNI <code>jchar</code>
3424 </constant>
3425 <constant id="JVMTI_PRIMITIVE_TYPE_SHORT" num="83">
3426 'S' - Java programming language <code>short</code> - JNI <code>jshort</code>
3427 </constant>
3428 <constant id="JVMTI_PRIMITIVE_TYPE_INT" num="73">
3429 'I' - Java programming language <code>int</code> - JNI <code>jint</code>
3430 </constant>
3431 <constant id="JVMTI_PRIMITIVE_TYPE_LONG" num="74">
3432 'J' - Java programming language <code>long</code> - JNI <code>jlong</code>
3433 </constant>
3434 <constant id="JVMTI_PRIMITIVE_TYPE_FLOAT" num="70">
3435 'F' - Java programming language <code>float</code> - JNI <code>jfloat</code>
3436 </constant>
3437 <constant id="JVMTI_PRIMITIVE_TYPE_DOUBLE" num="68">
3438 'D' - Java programming language <code>double</code> - JNI <code>jdouble</code>
3439 </constant>
3440 </constants>
3441 </intro>
3442
3443 <typedef id="jvmtiHeapReferenceInfoField"
3444 label="Reference information structure for Field references"
3445 since="1.1">
3446 <description>
3447 Reference information returned for
3448 <datalink id="JVMTI_HEAP_REFERENCE_FIELD"/> and
3449 <datalink id="JVMTI_HEAP_REFERENCE_STATIC_FIELD"/> references.
3450 </description>
3451 <field id="index">
3452 <jint/>
3453 <description>
3454 For <datalink id="JVMTI_HEAP_REFERENCE_FIELD"/>, the
3455 referrer object is not a class or an inteface.
3456 In this case, <code>index</code> is the index of the field
3457 in the class of the referrer object.
3458 This class is referred to below as <i>C</i>.
3459 <p/>
3460 For <datalink id="JVMTI_HEAP_REFERENCE_STATIC_FIELD"/>,
3461 the referrer object is a class (referred to below as <i>C</i>)
3462 or an interface (referred to below as <i>I</i>).
3463 In this case, <code>index</code> is the index of the field in
3464 that class or interface.
3465 <p/>
3466 If the referrer object is not an interface, then the field
3467 indices are determined as follows:
3468 <ul>
3469 <li>make a list of all the fields in <i>C</i> and its
3470 superclasses, starting with all the fields in
3471 <code>java.lang.Object</code> and ending with all the
3472 fields in <i>C</i>.</li>
3473 <li>Within this list, put
3474 the fields for a given class in the order returned by
3475 <functionlink id="GetClassFields"/>.</li>
3476 <li>Assign the fields in this list indices
3477 <i>n</i>, <i>n</i>+1, ..., in order, where <i>n</i>
3478 is the count of the fields in all the interfaces
3479 implemented by <i>C</i>.
3480 Note that <i>C</i> implements all interfaces
3481 directly implemented by its superclasses; as well
3482 as all superinterfaces of these interfaces.</li>
3483 </ul>
3484 If the referrer object is an interface, then the field
3485 indices are determined as follows:
3486 <ul>
3487 <li>make a list of the fields directly declared in
3488 <i>I</i>.</li>
3489 <li>Within this list, put
3490 the fields in the order returned by
3491 <functionlink id="GetClassFields"/>.</li>
3492 <li>Assign the fields in this list indices
3493 <i>n</i>, <i>n</i>+1, ..., in order, where <i>n</i>
3494 is the count of the fields in all the superinterfaces
3495 of <i>I</i>.</li>
3496 </ul>
3497 All fields are included in this computation, regardless of
3498 field modifier (static, public, private, etc).
3499 <p/>
3500 For example, given the following classes and interfaces:
3501 <example>
3502 interface I0 {
3503 int p = 0;
3504 }
3505
3506 interface I1 extends I0 {
3507 int x = 1;
3508 }
3509
3510 interface I2 extends I0 {
3511 int y = 2;
3512 }
3513
3514 class C1 implements I1 {
3515 public static int a = 3;
3516 private int b = 4;
3517 }
3518
3519 class C2 extends C1 implements I2 {
3520 static int q = 5;
3521 final int r = 6;
3522 }
3523 </example>
3524 Assume that <functionlink id="GetClassFields"/> called on
3525 <code>C1</code> returns the fields of <code>C1</code> in the
3526 order: a, b; and that the fields of <code>C2</code> are
3527 returned in the order: q, r.
3528 An instance of class <code>C1</code> will have the
3529 following field indices:
3530 <dl><dd><table>
3531 <tr>
3532 <td>
3533 a
3534 </td>
3535 <td>
3536 2
3537 </td>
3538 <td align="left">
3539 The count of the fields in the interfaces
3540 implemented by <code>C1</code> is two (<i>n</i>=2):
3541 <code>p</code> of <code>I0</code>
3542 and <code>x</code> of <code>I1</code>.
3543 </td>
3544 </tr>
3545 <tr>
3546 <td>
3547 b
3548 </td>
3549 <td>
3550 3
3551 </td>
3552 <td align="left">
3553 the subsequent index.
3554 </td>
3555 </tr>
3556 </table></dd></dl>
3557 The class <code>C1</code> will have the same field indices.
3558 <p/>
3559 An instance of class <code>C2</code> will have the
3560 following field indices:
3561 <dl><dd><table>
3562 <tr>
3563 <td>
3564 a
3565 </td>
3566 <td>
3567 3
3568 </td>
3569 <td align="left">
3570 The count of the fields in the interfaces
3571 implemented by <code>C2</code> is three (<i>n</i>=3):
3572 <code>p</code> of <code>I0</code>,
3573 <code>x</code> of <code>I1</code> and <code>y</code> of <code>I2</code>
3574 (an interface of <code>C2</code>). Note that the field <code>p</code>
3575 of <code>I0</code> is only included once.
3576 </td>
3577 </tr>
3578 <tr>
3579 <td>
3580 b
3581 </td>
3582 <td>
3583 4
3584 </td>
3585 <td align="left">
3586 the subsequent index to "a".
3587 </td>
3588 </tr>
3589 <tr>
3590 <td>
3591 q
3592 </td>
3593 <td>
3594 5
3595 </td>
3596 <td align="left">
3597 the subsequent index to "b".
3598 </td>
3599 </tr>
3600 <tr>
3601 <td>
3602 r
3603 </td>
3604 <td>
3605 6
3606 </td>
3607 <td align="left">
3608 the subsequent index to "q".
3609 </td>
3610 </tr>
3611 </table></dd></dl>
3612 The class <code>C2</code> will have the same field indices.
3613 Note that a field may have a different index depending on the
3614 object that is viewing it -- for example field "a" above.
3615 Note also: not all field indices may be visible from the
3616 callbacks, but all indices are shown for illustrative purposes.
3617 <p/>
3618 The interface <code>I1</code> will have the
3619 following field indices:
3620 <dl><dd><table>
3621 <tr>
3622 <td>
3623 x
3624 </td>
3625 <td>
3626 1
3627 </td>
3628 <td align="left">
3629 The count of the fields in the superinterfaces
3630 of <code>I1</code> is one (<i>n</i>=1):
3631 <code>p</code> of <code>I0</code>.
3632 </td>
3633 </tr>
3634 </table></dd></dl>
3635 </description>
3636 </field>
3637 </typedef>
3638
3639 <typedef id="jvmtiHeapReferenceInfoArray"
3640 label="Reference information structure for Array references"
3641 since="1.1">
3642 <description>
3643 Reference information returned for
3644 <datalink id="JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT"/> references.
3645 </description>
3646 <field id="index">
3647 <jint/>
3648 <description>
3649 The array index.
3650 </description>
3651 </field>
3652 </typedef>
3653
3654 <typedef id="jvmtiHeapReferenceInfoConstantPool"
3655 label="Reference information structure for Constant Pool references"
3656 since="1.1">
3657 <description>
3658 Reference information returned for
3659 <datalink id="JVMTI_HEAP_REFERENCE_CONSTANT_POOL"/> references.
3660 </description>
3661 <field id="index">
3662 <jint/>
3663 <description>
3664 The index into the constant pool of the class. See the description in
3665 <vmspec chapter="4.4"/>.
3666 </description>
3667 </field>
3668 </typedef>
3669
3670 <typedef id="jvmtiHeapReferenceInfoStackLocal"
3671 label="Reference information structure for Local Variable references"
3672 since="1.1">
3673 <description>
3674 Reference information returned for
3675 <datalink id="JVMTI_HEAP_REFERENCE_STACK_LOCAL"/> references.
3676 </description>
3677 <field id="thread_tag">
3678 <jlong/>
3679 <description>
3680 The tag of the thread corresponding to this stack, zero if not tagged.
3681 </description>
3682 </field>
3683 <field id="thread_id">
3684 <jlong/>
3685 <description>
3686 The unique thread ID of the thread corresponding to this stack.
3687 </description>
3688 </field>
3689 <field id="depth">
3690 <jint/>
3691 <description>
3692 The depth of the frame.
3693 </description>
3694 </field>
3695 <field id="method">
3696 <jmethodID/>
3697 <description>
3698 The method executing in this frame.
3699 </description>
3700 </field>
3701 <field id="location">
3702 <jlocation/>
3703 <description>
3704 The currently executing location in this frame.
3705 </description>
3706 </field>
3707 <field id="slot">
3708 <jint/>
3709 <description>
3710 The slot number of the local variable.
3711 </description>
3712 </field>
3713 </typedef>
3714
3715 <typedef id="jvmtiHeapReferenceInfoJniLocal"
3716 label="Reference information structure for JNI local references"
3717 since="1.1">
3718 <description>
3719 Reference information returned for
3720 <datalink id="JVMTI_HEAP_REFERENCE_JNI_LOCAL"/> references.
3721 </description>
3722 <field id="thread_tag">
3723 <jlong/>
3724 <description>
3725 The tag of the thread corresponding to this stack, zero if not tagged.
3726 </description>
3727 </field>
3728 <field id="thread_id">
3729 <jlong/>
3730 <description>
3731 The unique thread ID of the thread corresponding to this stack.
3732 </description>
3733 </field>
3734 <field id="depth">
3735 <jint/>
3736 <description>
3737 The depth of the frame.
3738 </description>
3739 </field>
3740 <field id="method">
3741 <jmethodID/>
3742 <description>
3743 The method executing in this frame.
3744 </description>
3745 </field>
3746 </typedef>
3747
3748 <typedef id="jvmtiHeapReferenceInfoReserved"
3749 label="Reference information structure for Other references"
3750 since="1.1">
3751 <description>
3752 Reference information returned for other references.
3753 </description>
3754 <field id="reserved1">
3755 <jlong/>
3756 <description>
3757 reserved for future use.
3758 </description>
3759 </field>
3760 <field id="reserved2">
3761 <jlong/>
3762 <description>
3763 reserved for future use.
3764 </description>
3765 </field>
3766 <field id="reserved3">
3767 <jlong/>
3768 <description>
3769 reserved for future use.
3770 </description>
3771 </field>
3772 <field id="reserved4">
3773 <jlong/>
3774 <description>
3775 reserved for future use.
3776 </description>
3777 </field>
3778 <field id="reserved5">
3779 <jlong/>
3780 <description>
3781 reserved for future use.
3782 </description>
3783 </field>
3784 <field id="reserved6">
3785 <jlong/>
3786 <description>
3787 reserved for future use.
3788 </description>
3789 </field>
3790 <field id="reserved7">
3791 <jlong/>
3792 <description>
3793 reserved for future use.
3794 </description>
3795 </field>
3796 <field id="reserved8">
3797 <jlong/>
3798 <description>
3799 reserved for future use.
3800 </description>
3801 </field>
3802 </typedef>
3803
3804 <uniontypedef id="jvmtiHeapReferenceInfo"
3805 label="Reference information structure"
3806 since="1.1">
3807 <description>
3808 The information returned about referrers.
3809 Represented as a union of the various kinds of reference information.
3810 </description>
3811 <field id="field">
3812 <struct>jvmtiHeapReferenceInfoField</struct>
3813 <description>
3814 The referrer information for
3815 <datalink id="JVMTI_HEAP_REFERENCE_FIELD"/>
3816 and <datalink id="JVMTI_HEAP_REFERENCE_STATIC_FIELD"/> references.
3817 </description>
3818 </field>
3819 <field id="array">
3820 <struct>jvmtiHeapReferenceInfoArray</struct>
3821 <description>
3822 The referrer information for
3823 For <datalink id="JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT"/> references.
3824 </description>
3825 </field>
3826 <field id="constant_pool">
3827 <struct>jvmtiHeapReferenceInfoConstantPool</struct>
3828 <description>
3829 The referrer information for
3830 For <datalink id="JVMTI_HEAP_REFERENCE_CONSTANT_POOL"/> references.
3831 </description>
3832 </field>
3833 <field id="stack_local">
3834 <struct>jvmtiHeapReferenceInfoStackLocal</struct>
3835 <description>
3836 The referrer information for
3837 For <datalink id="JVMTI_HEAP_REFERENCE_STACK_LOCAL"/> references.
3838 </description>
3839 </field>
3840 <field id="jni_local">
3841 <struct>jvmtiHeapReferenceInfoJniLocal</struct>
3842 <description>
3843 The referrer information for
3844 For <datalink id="JVMTI_HEAP_REFERENCE_JNI_LOCAL"/> references.
3845 </description>
3846 </field>
3847 <field id="other">
3848 <struct>jvmtiHeapReferenceInfoReserved</struct>
3849 <description>
3850 reserved for future use.
3851 </description>
3852 </field>
3853 </uniontypedef>
3854
3855 <typedef id="jvmtiHeapCallbacks"
3856 label="Heap callback function structure"
3857 since="1.1">
3858 <field id="heap_iteration_callback">
3859 <ptrtype>
3860 <struct>jvmtiHeapIterationCallback</struct>
3861 </ptrtype>
3862 <description>
3863 The callback to be called to describe an
3864 object in the heap. Used by the
3865 <functionlink id="IterateThroughHeap"/> function, ignored by the
3866 <functionlink id="FollowReferences"/> function.
3867 </description>
3868 </field>
3869 <field id="heap_reference_callback">
3870 <ptrtype>
3871 <struct>jvmtiHeapReferenceCallback</struct>
3872 </ptrtype>
3873 <description>
3874 The callback to be called to describe an
3875 object reference. Used by the
3876 <functionlink id="FollowReferences"/> function, ignored by the
3877 <functionlink id="IterateThroughHeap"/> function.
3878 </description>
3879 </field>
3880 <field id="primitive_field_callback">
3881 <ptrtype>
3882 <struct>jvmtiPrimitiveFieldCallback</struct>
3883 </ptrtype>
3884 <description>
3885 The callback to be called to describe a
3886 primitive field.
3887 </description>
3888 </field>
3889 <field id="array_primitive_value_callback">
3890 <ptrtype>
3891 <struct>jvmtiArrayPrimitiveValueCallback</struct>
3892 </ptrtype>
3893 <description>
3894 The callback to be called to describe an
3895 array of primitive values.
3896 </description>
3897 </field>
3898 <field id="string_primitive_value_callback">
3899 <ptrtype>
3900 <struct>jvmtiStringPrimitiveValueCallback</struct>
3901 </ptrtype>
3902 <description>
3903 The callback to be called to describe a String value.
3904 </description>
3905 </field>
3906 <field id="reserved5">
3907 <ptrtype>
3908 <struct>jvmtiReservedCallback</struct>
3909 </ptrtype>
3910 <description>
3911 Reserved for future use..
3912 </description>
3913 </field>
3914 <field id="reserved6">
3915 <ptrtype>
3916 <struct>jvmtiReservedCallback</struct>
3917 </ptrtype>
3918 <description>
3919 Reserved for future use..
3920 </description>
3921 </field>
3922 <field id="reserved7">
3923 <ptrtype>
3924 <struct>jvmtiReservedCallback</struct>
3925 </ptrtype>
3926 <description>
3927 Reserved for future use..
3928 </description>
3929 </field>
3930 <field id="reserved8">
3931 <ptrtype>
3932 <struct>jvmtiReservedCallback</struct>
3933 </ptrtype>
3934 <description>
3935 Reserved for future use..
3936 </description>
3937 </field>
3938 <field id="reserved9">
3939 <ptrtype>
3940 <struct>jvmtiReservedCallback</struct>
3941 </ptrtype>
3942 <description>
3943 Reserved for future use..
3944 </description>
3945 </field>
3946 <field id="reserved10">
3947 <ptrtype>
3948 <struct>jvmtiReservedCallback</struct>
3949 </ptrtype>
3950 <description>
3951 Reserved for future use..
3952 </description>
3953 </field>
3954 <field id="reserved11">
3955 <ptrtype>
3956 <struct>jvmtiReservedCallback</struct>
3957 </ptrtype>
3958 <description>
3959 Reserved for future use..
3960 </description>
3961 </field>
3962 <field id="reserved12">
3963 <ptrtype>
3964 <struct>jvmtiReservedCallback</struct>
3965 </ptrtype>
3966 <description>
3967 Reserved for future use..
3968 </description>
3969 </field>
3970 <field id="reserved13">
3971 <ptrtype>
3972 <struct>jvmtiReservedCallback</struct>
3973 </ptrtype>
3974 <description>
3975 Reserved for future use..
3976 </description>
3977 </field>
3978 <field id="reserved14">
3979 <ptrtype>
3980 <struct>jvmtiReservedCallback</struct>
3981 </ptrtype>
3982 <description>
3983 Reserved for future use..
3984 </description>
3985 </field>
3986 <field id="reserved15">
3987 <ptrtype>
3988 <struct>jvmtiReservedCallback</struct>
3989 </ptrtype>
3990 <description>
3991 Reserved for future use..
3992 </description>
3993 </field>
3994 </typedef>
3995
3996
3997 <intro>
3998 <rationale>
3999 The heap dumping functionality (below) uses a callback
4000 for each object. While it would seem that a buffered approach
4001 would provide better throughput, tests do
4002 not show this to be the case--possibly due to locality of
4003 memory reference or array access overhead.
4004 </rationale>
4005
4006 <issue>
4007 Still under investigation as to if java.lang.ref references
4008 are reported as a different type of reference.
4009 </issue>
4010
4011 <issue>
4012 Should or can an indication of the cost or relative cost of
4013 these operations be included?
4014 </issue>
4015
4016 </intro>
4017
4018 <callback id="jvmtiHeapIterationCallback" since="1.1">
4019 <jint/>
4020 <synopsis>Heap Iteration Callback</synopsis>
4021 <description>
4022 Agent supplied callback function.
4023 Describes (but does not pass in) an object in the heap.
4024 <p/>
4025 This function should return a bit vector of the desired
4026 <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>.
4027 This will determine if the entire iteration should be aborted
4028 (the <code>JVMTI_VISIT_OBJECTS</code> flag is ignored).
4029 <p/>
4030 See the <internallink id="heapCallbacks">heap callback
4031 function restrictions</internallink>.
4032 </description>
4033 <parameters>
4034 <param id="class_tag">
4035 <jlong/>
4036 <description>
4037 The tag of the class of object (zero if the class is not tagged).
4038 If the object represents a runtime class,
4039 the <code>class_tag</code> is the tag
4040 associated with <code>java.lang.Class</code>
4041 (zero if <code>java.lang.Class</code> is not tagged).
4042 </description>
4043 </param>
4044 <param id="size">
4045 <jlong/>
4046 <description>
4047 Size of the object (in bytes). See <functionlink id="GetObjectSize"/>.
4048 </description>
4049 </param>
4050 <param id="tag_ptr">
4051 <outptr><jlong/></outptr>
4052 <description>
4053 The object tag value, or zero if the object is not tagged.
4054 To set the tag value to be associated with the object
4055 the agent sets the <code>jlong</code> pointed to by the parameter.
4056 </description>
4057 </param>
4058 <param id="length">
4059 <jint/>
4060 <description>
4061 If this object is an array, the length of the array. Otherwise negative one (-1).
4062 </description>
4063 </param>
4064 <param id="user_data">
4065 <outptr><void/></outptr>
4066 <description>
4067 The user supplied data that was passed into the iteration function.
4068 </description>
4069 </param>
4070 </parameters>
4071 </callback>
4072
4073 <callback id="jvmtiHeapReferenceCallback" since="1.1">
4074 <jint/>
4075 <synopsis>Heap Reference Callback</synopsis>
4076 <description>
4077 Agent supplied callback function.
4078 Describes a reference from an object or the VM (the referrer) to another object
4079 (the referree) or a heap root to a referree.
4080 <p/>
4081 This function should return a bit vector of the desired
4082 <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>.
4083 This will determine if the objects referenced by the referree
4084 should be visited or if the entire iteration should be aborted.
4085 <p/>
4086 See the <internallink id="heapCallbacks">heap callback
4087 function restrictions</internallink>.
4088 </description>
4089 <parameters>
4090 <param id="reference_kind">
4091 <enum>jvmtiHeapReferenceKind</enum>
4092 <description>
4093 The kind of reference.
4094 </description>
4095 </param>
4096 <param id="reference_info">
4097 <inptr>
4098 <struct>jvmtiHeapReferenceInfo</struct>
4099 </inptr>
4100 <description>
4101 Details about the reference.
4102 Set when the <datalink id="jvmtiHeapReferenceCallback.reference_kind">reference_kind</datalink> is
4103 <datalink id="JVMTI_HEAP_REFERENCE_FIELD"/>,
4104 <datalink id="JVMTI_HEAP_REFERENCE_STATIC_FIELD"/>,
4105 <datalink id="JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT"/>,
4106 <datalink id="JVMTI_HEAP_REFERENCE_CONSTANT_POOL"/>,
4107 <datalink id="JVMTI_HEAP_REFERENCE_STACK_LOCAL"/>,
4108 or <datalink id="JVMTI_HEAP_REFERENCE_JNI_LOCAL"/>.
4109 Otherwise <code>NULL</code>.
4110 </description>
4111 </param>
4112 <param id="class_tag">
4113 <jlong/>
4114 <description>
4115 The tag of the class of referree object (zero if the class is not tagged).
4116 If the referree object represents a runtime class,
4117 the <code>class_tag</code> is the tag
4118 associated with <code>java.lang.Class</code>
4119 (zero if <code>java.lang.Class</code> is not tagged).
4120 </description>
4121 </param>
4122 <param id="referrer_class_tag">
4123 <jlong/>
4124 <description>
4125 The tag of the class of the referrer object (zero if the class is not tagged
4126 or the referree is a heap root). If the referrer object represents a runtime
4127 class, the <code>referrer_class_tag</code> is the tag associated with
4128 the <code>java.lang.Class</code>
4129 (zero if <code>java.lang.Class</code> is not tagged).
4130 </description>
4131 </param>
4132 <param id="size">
4133 <jlong/>
4134 <description>
4135 Size of the referree object (in bytes).
4136 See <functionlink id="GetObjectSize"/>.
4137 </description>
4138 </param>
4139 <param id="tag_ptr">
4140 <outptr><jlong/></outptr>
4141 <description>
4142 Points to the referree object tag value, or zero if the object is not
4143 tagged.
4144 To set the tag value to be associated with the object
4145 the agent sets the <code>jlong</code> pointed to by the parameter.
4146 </description>
4147 </param>
4148 <param id="referrer_tag_ptr">
4149 <outptr><jlong/></outptr>
4150 <description>
4151 Points to the tag of the referrer object, or
4152 points to the zero if the referrer
4153 object is not tagged.
4154 <code>NULL</code> if the referrer in not an object (that is,
4155 this callback is reporting a heap root).
4156 To set the tag value to be associated with the referrer object
4157 the agent sets the <code>jlong</code> pointed to by the parameter.
4158 If this callback is reporting a reference from an object to itself,
4159 <code>referrer_tag_ptr == tag_ptr</code>.
4160 </description>
4161 </param>
4162 <param id="length">
4163 <jint/>
4164 <description>
4165 If this object is an array, the length of the array. Otherwise negative one (-1).
4166 </description>
4167 </param>
4168 <param id="user_data">
4169 <outptr><void/></outptr>
4170 <description>
4171 The user supplied data that was passed into the iteration function.
4172 </description>
4173 </param>
4174 </parameters>
4175 </callback>
4176
4177 <callback id="jvmtiPrimitiveFieldCallback" since="1.1">
4178 <jint/>
4179 <synopsis>Primitive Field Callback</synopsis>
4180 <description>
4181 Agent supplied callback function which
4182 describes a primitive field of an object (<i>the object</i>).
4183 A primitive field is a field whose type is a primitive type.
4184 This callback will describe a static field if the object is a class,
4185 and otherwise will describe an instance field.
4186 <p/>
4187 This function should return a bit vector of the desired
4188 <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>.
4189 This will determine if the entire iteration should be aborted
4190 (the <code>JVMTI_VISIT_OBJECTS</code> flag is ignored).
4191 <p/>
4192 See the <internallink id="heapCallbacks">heap callback
4193 function restrictions</internallink>.
4194 </description>
4195 <parameters>
4196 <param id="kind">
4197 <enum>jvmtiHeapReferenceKind</enum>
4198 <description>
4199 The kind of field -- instance or static (<datalink id="JVMTI_HEAP_REFERENCE_FIELD"/> or
4200 <datalink id="JVMTI_HEAP_REFERENCE_STATIC_FIELD"/>).
4201 </description>
4202 </param>
4203 <param id="info">
4204 <inptr>
4205 <struct>jvmtiHeapReferenceInfo</struct>
4206 </inptr>
4207 <description>
4208 Which field (the field index).
4209 </description>
4210 </param>
4211 <param id="object_class_tag">
4212 <jlong/>
4213 <description>
4214 The tag of the class of the object (zero if the class is not tagged).
4215 If the object represents a runtime class, the
4216 <code>object_class_tag</code> is the tag
4217 associated with <code>java.lang.Class</code>
4218 (zero if <code>java.lang.Class</code> is not tagged).
4219 </description>
4220 </param>
4221 <param id="object_tag_ptr">
4222 <outptr><jlong/></outptr>
4223 <description>
4224 Points to the tag of the object, or zero if the object is not
4225 tagged.
4226 To set the tag value to be associated with the object
4227 the agent sets the <code>jlong</code> pointed to by the parameter.
4228 </description>
4229 </param>
4230 <param id="value">
4231 <jvalue/>
4232 <description>
4233 The value of the field.
4234 </description>
4235 </param>
4236 <param id="value_type">
4237 <enum>jvmtiPrimitiveType</enum>
4238 <description>
4239 The type of the field.
4240 </description>
4241 </param>
4242 <param id="user_data">
4243 <outptr><void/></outptr>
4244 <description>
4245 The user supplied data that was passed into the iteration function.
4246 </description>
4247 </param>
4248 </parameters>
4249 </callback>
4250
4251 <callback id="jvmtiArrayPrimitiveValueCallback" since="1.1">
4252 <jint/>
4253 <synopsis>Array Primitive Value Callback</synopsis>
4254 <description>
4255 Agent supplied callback function.
4256 Describes the values in an array of a primitive type.
4257 <p/>
4258 This function should return a bit vector of the desired
4259 <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>.
4260 This will determine if the entire iteration should be aborted
4261 (the <code>JVMTI_VISIT_OBJECTS</code> flag is ignored).
4262 <p/>
4263 See the <internallink id="heapCallbacks">heap callback
4264 function restrictions</internallink>.
4265 </description>
4266 <parameters>
4267 <param id="class_tag">
4268 <jlong/>
4269 <description>
4270 The tag of the class of the array object (zero if the class is not tagged).
4271 </description>
4272 </param>
4273 <param id="size">
4274 <jlong/>
4275 <description>
4276 Size of the array (in bytes).
4277 See <functionlink id="GetObjectSize"/>.
4278 </description>
4279 </param>
4280 <param id="tag_ptr">
4281 <outptr><jlong/></outptr>
4282 <description>
4283 Points to the tag of the array object, or zero if the object is not
4284 tagged.
4285 To set the tag value to be associated with the object
4286 the agent sets the <code>jlong</code> pointed to by the parameter.
4287 </description>
4288 </param>
4289 <param id="element_count">
4290 <jint/>
4291 <description>
4292 The length of the primitive array.
4293 </description>
4294 </param>
4295 <param id="element_type">
4296 <enum>jvmtiPrimitiveType</enum>
4297 <description>
4298 The type of the elements of the array.
4299 </description>
4300 </param>
4301 <param id="elements">
4302 <vmbuf><void/></vmbuf>
4303 <description>
4304 The elements of the array in a packed array of <code>element_count</code>
4305 items of <code>element_type</code> size each.
4306 </description>
4307 </param>
4308 <param id="user_data">
4309 <outptr><void/></outptr>
4310 <description>
4311 The user supplied data that was passed into the iteration function.
4312 </description>
4313 </param>
4314 </parameters>
4315 </callback>
4316
4317 <callback id="jvmtiStringPrimitiveValueCallback" since="1.1">
4318 <jint/>
4319 <synopsis>String Primitive Value Callback</synopsis>
4320 <description>
4321 Agent supplied callback function.
4322 Describes the value of a java.lang.String.
4323 <p/>
4324 This function should return a bit vector of the desired
4325 <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>.
4326 This will determine if the entire iteration should be aborted
4327 (the <code>JVMTI_VISIT_OBJECTS</code> flag is ignored).
4328 <p/>
4329 See the <internallink id="heapCallbacks">heap callback
4330 function restrictions</internallink>.
4331 </description>
4332 <parameters>
4333 <param id="class_tag">
4334 <jlong/>
4335 <description>
4336 The tag of the class of the String class (zero if the class is not tagged).
4337 <issue>Is this needed?</issue>
4338 </description>
4339 </param>
4340 <param id="size">
4341 <jlong/>
4342 <description>
4343 Size of the string (in bytes).
4344 See <functionlink id="GetObjectSize"/>.
4345 </description>
4346 </param>
4347 <param id="tag_ptr">
4348 <outptr><jlong/></outptr>
4349 <description>
4350 Points to the tag of the String object, or zero if the object is not
4351 tagged.
4352 To set the tag value to be associated with the object
4353 the agent sets the <code>jlong</code> pointed to by the parameter.
4354 </description>
4355 </param>
4356 <param id="value">
4357 <vmbuf><jchar/></vmbuf>
4358 <description>
4359 The value of the String, encoded as a Unicode string.
4360 </description>
4361 </param>
4362 <param id="value_length">
4363 <jint/>
4364 <description>
4365 The length of the string.
4366 The length is equal to the number of 16-bit Unicode
4367 characters in the string.
4368 </description>
4369 </param>
4370 <param id="user_data">
4371 <outptr><void/></outptr>
4372 <description>
4373 The user supplied data that was passed into the iteration function.
4374 </description>
4375 </param>
4376 </parameters>
4377 </callback>
4378
4379
4380 <callback id="jvmtiReservedCallback" since="1.1">
4381 <jint/>
4382 <synopsis>reserved for future use Callback</synopsis>
4383 <description>
4384 Placeholder -- reserved for future use.
4385 </description>
4386 <parameters>
4387 </parameters>
4388 </callback>
4389
4390 <function id="FollowReferences" num="115" since="1.1">
4391 <synopsis>Follow References</synopsis>
4392 <description>
4393 This function initiates a traversal over the objects that are
4394 directly and indirectly reachable from the specified object or,
4395 if <code>initial_object</code> is not specified, all objects
4396 reachable from the heap roots.
4397 The heap root are the set of system classes,
4398 JNI globals, references from thread stacks, and other objects used as roots
4399 for the purposes of garbage collection.
4400 <p/>
4401 This function operates by traversing the reference graph.
4402 Let <i>A</i>, <i>B</i>, ... represent objects.
4403 When a reference from <i>A</i> to <i>B</i> is traversed,
4404 when a reference from a heap root to <i>B</i> is traversed,
4405 or when <i>B</i> is specified as the <paramlink id="initial_object"/>,
4406 then <i>B</i> is said to be <i>visited</i>.
4407 A reference from <i>A</i> to <i>B</i> is not traversed until <i>A</i>
4408 is visited.
4409 References are reported in the same order that the references are traversed.
4410 Object references are reported by invoking the agent supplied
4411 callback function <functionlink id="jvmtiHeapReferenceCallback"/>.
4412 In a reference from <i>A</i> to <i>B</i>, <i>A</i> is known
4413 as the <i>referrer</i> and <i>B</i> as the <i>referree</i>.
4414 The callback is invoked exactly once for each reference from a referrer;
4415 this is true even if there are reference cycles or multiple paths to
4416 the referrer.
4417 There may be more than one reference between a referrer and a referree,
4418 each reference is reported.
4419 These references may be distinguished by examining the
4420 <datalink
4421 id="jvmtiHeapReferenceCallback.reference_kind"><code>reference_kind</code></datalink>
4422 and
4423 <datalink
4424 id="jvmtiHeapReferenceCallback.reference_info"><code>reference_info</code></datalink>
4425 parameters of the <functionlink id="jvmtiHeapReferenceCallback"/> callback.
4426 <p/>
4427 This function reports a Java programming language view of object references,
4428 not a virtual machine implementation view. The following object references
4429 are reported when they are non-null:
4430 <ul>
4431 <li>Instance objects report references to each non-primitive instance fields
4432 (including inherited fields).</li>
4433 <li>Instance objects report a reference to the object type (class).</li>
4434 <li>Classes report a reference to the superclass and directly
4435 implemented/extended interfaces.</li>
4436 <li>Classes report a reference to the class loader, protection domain,
4437 signers, and resolved entries in the constant pool.</li>
4438 <li>Classes report a reference to each directly declared non-primitive
4439 static field.</li>
4440 <li>Arrays report a reference to the array type (class) and each
4441 array element.</li>
4442 <li>Primitive arrays report a reference to the array type.</li>
4443 </ul>
4444 <p/>
4445 This function can also be used to examine primitive (non-object) values.
4446 The primitive value of an array or String
4447 is reported after the object has been visited;
4448 it is reported by invoking the agent supplied callback function
4449 <functionlink id="jvmtiArrayPrimitiveValueCallback"/> or
4450 <functionlink id="jvmtiStringPrimitiveValueCallback"/>.
4451 A primitive field
4452 is reported after the object with that field is visited;
4453 it is reported by invoking the agent supplied callback function
4454 <functionlink id="jvmtiPrimitiveFieldCallback"/>.
4455 <p/>
4456 Whether a callback is provided or is <code>NULL</code> only determines
4457 whether the callback will be invoked, it does not influence
4458 which objects are visited nor does it influence whether other callbacks
4459 will be invoked.
4460 However, the
4461 <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>
4462 returned by <functionlink id="jvmtiHeapReferenceCallback"/>
4463 do determine if the objects referenced by the
4464 current object as visited.
4465 The <datalink id="jvmtiHeapFilter">heap filter flags</datalink>
4466 and <paramlink id="klass"/> provided as parameters to this function
4467 do not control which objects are visited but they do control which
4468 objects and primitive values are reported by the callbacks.
4469 For example, if the only callback that was set is
4470 <fieldlink id="array_primitive_value_callback" struct="jvmtiHeapCallbacks"/> and <code>klass</code>
4471 is set to the array of bytes class, then only arrays of byte will be
4472 reported.
4473 The table below summarizes this:
4474 <p/>
4475 <table>
4476 <tr>
4477 <th/>
4478 <th>
4479 Controls objects visited
4480 </th>
4481 <th>
4482 Controls objects reported
4483 </th>
4484 <th>
4485 Controls primitives reported
4486 </th>
4487 </tr>
4488 <tr>
4489 <th align="left">
4490 the
4491 <datalink id="jvmtiHeapVisitControl">Heap Visit Control Flags</datalink>
4492 returned by <functionlink id="jvmtiHeapReferenceCallback"/>
4493 </th>
4494 <td>
4495 <b>Yes</b>
4496 </td>
4497 <td>
4498 <b>Yes</b>, since visits are controlled
4499 </td>
4500 <td>
4501 <b>Yes</b>, since visits are controlled
4502 </td>
4503 </tr>
4504 <tr>
4505 <th align="left">
4506 <fieldlink id="array_primitive_value_callback" struct="jvmtiHeapCallbacks"/>
4507 in <paramlink id="callbacks"/> set
4508 </th>
4509 <td>
4510 No
4511 </td>
4512 <td>
4513 <b>Yes</b>
4514 </td>
4515 <td>
4516 No
4517 </td>
4518 </tr>
4519 <tr>
4520 <th align="left">
4521 <paramlink id="heap_filter"/>
4522 </th>
4523 <td>
4524 No
4525 </td>
4526 <td>
4527 <b>Yes</b>
4528 </td>
4529 <td>
4530 <b>Yes</b>
4531 </td>
4532 </tr>
4533 <tr>
4534 <th align="left">
4535 <paramlink id="klass"/>
4536 </th>
4537 <td>
4538 No
4539 </td>
4540 <td>
4541 <b>Yes</b>
4542 </td>
4543 <td>
4544 <b>Yes</b>
4545 </td>
4546 </tr>
4547 </table>
4548 <p/>
4549 During the execution of this function the state of the heap
4550 does not change: no objects are allocated, no objects are
4551 garbage collected, and the state of objects (including
4552 held values) does not change.
4553 As a result, threads executing Java
4554 programming language code, threads attempting to resume the
4555 execution of Java programming language code, and threads
4556 attempting to execute JNI functions are typically stalled.
4557 </description>
4558 <origin>new</origin>
4559 <capabilities>
4560 <required id="can_tag_objects"></required>
4561 </capabilities>
4562 <parameters>
4563 <param id="heap_filter">
4564 <jint/>
4565 <description>
4566 This bit vector of
4567 <datalink id="jvmtiHeapFilter">heap filter flags</datalink>.
4568 restricts the objects for which the callback function is called.
4569 This applies to both the object and primitive callbacks.
4570 </description>
4571 </param>
4572 <param id="klass">
4573 <ptrtype>
4574 <jclass/>
4575 <nullok>callbacks are not limited to instances of a particular
4576 class</nullok>
4577 </ptrtype>
4578 <description>
4579 Callbacks are only reported when the object is an instance of
4580 this class.
4581 Objects which are instances of a subclass of <code>klass</code>
4582 are not reported.
4583 If <code>klass</code> is an interface, no objects are reported.
4584 This applies to both the object and primitive callbacks.
4585 </description>
4586 </param>
4587 <param id="initial_object">
4588 <ptrtype>
4589 <jobject/>
4590 <nullok>references are followed from the heap roots</nullok>
4591 </ptrtype>
4592 <description>
4593 The object to follow
4594 </description>
4595 </param>
4596 <param id="callbacks">
4597 <inptr>
4598 <struct>jvmtiHeapCallbacks</struct>
4599 </inptr>
4600 <description>
4601 Structure defining the set of callback functions.
4602 </description>
4603 </param>
4604 <param id="user_data">
4605 <inbuf>
4606 <void/>
4607 <nullok><code>NULL</code> is passed as the user supplied data</nullok>
4608 </inbuf>
4609 <description>
4610 User supplied data to be passed to the callback.
4611 </description>
4612 </param>
4613 </parameters>
4614 <errors>
4615 <error id="JVMTI_ERROR_INVALID_CLASS">
4616 <paramlink id="klass"/> is not a valid class.
4617 </error>
4618 <error id="JVMTI_ERROR_INVALID_OBJECT">
4619 <paramlink id="initial_object"/> is not a valid object.
4620 </error>
4621 </errors>
4622 </function>
4623
4624
4625 <function id="IterateThroughHeap" num="116" since="1.1">
4626 <synopsis>Iterate Through Heap</synopsis>
4627 <description>
4628 Initiate an iteration over all objects in the heap.
4629 This includes both reachable and
4630 unreachable objects. Objects are visited in no particular order.
4631 <p/>
4632 Heap objects are reported by invoking the agent supplied
4633 callback function <functionlink id="jvmtiHeapIterationCallback"/>.
4634 References between objects are not reported.
4635 If only reachable objects are desired, or if object reference information
4636 is needed, use <functionlink id="FollowReferences"/>.
4637 <p/>
4638 This function can also be used to examine primitive (non-object) values.
4639 The primitive value of an array or String
4640 is reported after the object has been visited;
4641 it is reported by invoking the agent supplied callback function
4642 <functionlink id="jvmtiArrayPrimitiveValueCallback"/> or
4643 <functionlink id="jvmtiStringPrimitiveValueCallback"/>.
4644 A primitive field
4645 is reported after the object with that field is visited;
4646 it is reported by invoking the agent supplied
4647 callback function
4648 <functionlink id="jvmtiPrimitiveFieldCallback"/>.
4649 <p/>
4650 Unless the iteration is aborted by the
4651 <datalink id="jvmtiHeapVisitControl">Heap Visit Control Flags</datalink>
4652 returned by a callback, all objects in the heap are visited.
4653 Whether a callback is provided or is <code>NULL</code> only determines
4654 whether the callback will be invoked, it does not influence
4655 which objects are visited nor does it influence whether other callbacks
4656 will be invoked.
4657 The <datalink id="jvmtiHeapFilter">heap filter flags</datalink>
4658 and <paramlink id="klass"/> provided as parameters to this function
4659 do not control which objects are visited but they do control which
4660 objects and primitive values are reported by the callbacks.
4661 For example, if the only callback that was set is
4662 <fieldlink id="array_primitive_value_callback" struct="jvmtiHeapCallbacks"/> and <code>klass</code>
4663 is set to the array of bytes class, then only arrays of byte will be
4664 reported. The table below summarizes this (contrast this with
4665 <functionlink id="FollowReferences"/>):
4666 <p/>
4667 <table>
4668 <tr>
4669 <th/>
4670 <th>
4671 Controls objects visited
4672 </th>
4673 <th>
4674 Controls objects reported
4675 </th>
4676 <th>
4677 Controls primitives reported
4678 </th>
4679 </tr>
4680 <tr>
4681 <th align="left">
4682 the
4683 <datalink id="jvmtiHeapVisitControl">Heap Visit Control Flags</datalink>
4684 returned by <functionlink id="jvmtiHeapIterationCallback"/>
4685 </th>
4686 <td>
4687 No<br/>(unless they abort the iteration)
4688 </td>
4689 <td>
4690 No<br/>(unless they abort the iteration)
4691 </td>
4692 <td>
4693 No<br/>(unless they abort the iteration)
4694 </td>
4695 </tr>
4696 <tr>
4697 <th align="left">
4698 <fieldlink id="array_primitive_value_callback" struct="jvmtiHeapCallbacks"/>
4699 in <paramlink id="callbacks"/> set
4700 </th>
4701 <td>
4702 No
4703 </td>
4704 <td>
4705 <b>Yes</b>
4706 </td>
4707 <td>
4708 No
4709 </td>
4710 </tr>
4711 <tr>
4712 <th align="left">
4713 <paramlink id="heap_filter"/>
4714 </th>
4715 <td>
4716 No
4717 </td>
4718 <td>
4719 <b>Yes</b>
4720 </td>
4721 <td>
4722 <b>Yes</b>
4723 </td>
4724 </tr>
4725 <tr>
4726 <th align="left">
4727 <paramlink id="klass"/>
4728 </th>
4729 <td>
4730 No
4731 </td>
4732 <td>
4733 <b>Yes</b>
4734 </td>
4735 <td>
4736 <b>Yes</b>
4737 </td>
4738 </tr>
4739 </table>
4740 <p/>
4741 During the execution of this function the state of the heap
4742 does not change: no objects are allocated, no objects are
4743 garbage collected, and the state of objects (including
4744 held values) does not change.
4745 As a result, threads executing Java
4746 programming language code, threads attempting to resume the
4747 execution of Java programming language code, and threads
4748 attempting to execute JNI functions are typically stalled.
4749 </description>
4750 <origin>new</origin>
4751 <capabilities>
4752 <required id="can_tag_objects"></required>
4753 </capabilities>
4754 <parameters>
4755 <param id="heap_filter">
4756 <jint/>
4757 <description>
4758 This bit vector of
4759 <datalink id="jvmtiHeapFilter">heap filter flags</datalink>.
4760 restricts the objects for which the callback function is called.
4761 This applies to both the object and primitive callbacks.
4762 </description>
4763 </param>
4764 <param id="klass">
4765 <ptrtype>
4766 <jclass/>
4767 <nullok>callbacks are not limited to instances of a particular class</nullok>
4768 </ptrtype>
4769 <description>
4770 Callbacks are only reported when the object is an instance of
4771 this class.
4772 Objects which are instances of a subclass of <code>klass</code>
4773 are not reported.
4774 If <code>klass</code> is an interface, no objects are reported.
4775 This applies to both the object and primitive callbacks.
4776 </description>
4777 </param>
4778 <param id="callbacks">
4779 <inptr>
4780 <struct>jvmtiHeapCallbacks</struct>
4781 </inptr>
4782 <description>
4783 Structure defining the set callback functions.
4784 </description>
4785 </param>
4786 <param id="user_data">
4787 <inbuf>
4788 <void/>
4789 <nullok><code>NULL</code> is passed as the user supplied data</nullok>
4790 </inbuf>
4791 <description>
4792 User supplied data to be passed to the callback.
4793 </description>
4794 </param>
4795 </parameters>
4796 <errors>
4797 <error id="JVMTI_ERROR_INVALID_CLASS">
4798 <paramlink id="klass"/> is not a valid class.
4799 </error>
4800 </errors>
4801 </function>
4802
4803 <function id="GetTag" phase="start" num="106">
4804 <synopsis>Get Tag</synopsis>
4805 <description>
4806 Retrieve the tag associated with an object.
4807 The tag is a long value typically used to store a
4808 unique identifier or pointer to object information.
4809 The tag is set with
4810 <functionlink id="SetTag"></functionlink>.
4811 Objects for which no tags have been set return a
4812 tag value of zero.
4813 </description>
4814 <origin>new</origin>
4815 <capabilities>
4816 <required id="can_tag_objects"></required>
4817 </capabilities>
4818 <parameters>
4819 <param id="object">
4820 <jobject/>
4821 <description>
4822 The object whose tag is to be retrieved.
4823 </description>
4824 </param>
4825 <param id="tag_ptr">
4826 <outptr><jlong/></outptr>
4827 <description>
4828 On return, the referenced long is set to the value
4829 of the tag.
4830 </description>
4831 </param>
4832 </parameters>
4833 <errors>
4834 </errors>
4835 </function>
4836
4837 <function id="SetTag" phase="start" num="107">
4838 <synopsis>Set Tag</synopsis>
4839 <description>
4840 Set the tag associated with an object.
4841 The tag is a long value typically used to store a
4842 unique identifier or pointer to object information.
4843 The tag is visible with
4844 <functionlink id="GetTag"></functionlink>.
4845 </description>
4846 <origin>new</origin>
4847 <capabilities>
4848 <required id="can_tag_objects"></required>
4849 </capabilities>
4850 <parameters>
4851 <param id="object">
4852 <jobject/>
4853 <description>
4854 The object whose tag is to be set.
4855 </description>
4856 </param>
4857 <param id="tag">
4858 <jlong/>
4859 <description>
4860 The new value of the tag.
4861 </description>
4862 </param>
4863 </parameters>
4864 <errors>
4865 </errors>
4866 </function>
4867
4868 <function id="GetObjectsWithTags" num="114">
4869 <synopsis>Get Objects With Tags</synopsis>
4870 <description>
4871 Return objects in the heap with the specified tags.
4872 The format is parallel arrays of objects and tags.
4873 </description>
4874 <origin>new</origin>
4875 <capabilities>
4876 <required id="can_tag_objects"></required>
4877 </capabilities>
4878 <parameters>
4879 <param id="tag_count">
4880 <jint min="0"/>
4881 <description>
4882 Number of tags to scan for.
4883 </description>
4884 </param>
4885 <param id="tags">
4886 <inbuf incount="tag_count">
4887 <jlong/>
4888 </inbuf>
4889 <description>
4890 Scan for objects with these tags.
4891 Zero is not permitted in this array.
4892 </description>
4893 </param>
4894 <param id="count_ptr">
4895 <outptr>
4896 <jint/>
4897 </outptr>
4898 <description>
4899 Return the number of objects with any of the tags
4900 in <paramlink id="tags"/>.
4901 </description>
4902 </param>
4903 <param id="object_result_ptr">
4904 <allocbuf outcount="count_ptr">
4905 <jobject/>
4906 <nullok>this information is not returned</nullok>
4907 </allocbuf>
4908 <description>
4909 Returns the array of objects with any of the tags
4910 in <paramlink id="tags"/>.
4911 </description>
4912 </param>
4913 <param id="tag_result_ptr">
4914 <allocbuf outcount="count_ptr">
4915 <jlong/>
4916 <nullok>this information is not returned</nullok>
4917 </allocbuf>
4918 <description>
4919 For each object in <paramlink id="object_result_ptr"/>,
4920 return the tag at the corresponding index.
4921 </description>
4922 </param>
4923 </parameters>
4924 <errors>
4925 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
4926 Zero is present in <paramlink id="tags"></paramlink>.
4927 </error>
4928 </errors>
4929 </function>
4930
4931 <function id="ForceGarbageCollection" num="108">
4932 <synopsis>Force Garbage Collection</synopsis>
4933 <description>
4934 Force the VM to perform a garbage collection.
4935 The garbage collection is as complete as possible.
4936 This function does not cause finalizers to be run.
4937 This function does not return until the garbage collection
4938 is finished.
4939 <p/>
4940 Although garbage collection is as complete
4941 as possible there is no guarantee that all
4942 <eventlink id="ObjectFree"/>
4943 events will have been
4944 sent by the time that this function
4945 returns. In particular, an object may be
4946 prevented from being freed because it
4947 is awaiting finalization.
4948 </description>
4949 <origin>new</origin>
4950 <capabilities>
4951 </capabilities>
4952 <parameters>
4953 </parameters>
4954 <errors>
4955 </errors>
4956 </function>
4957
4958
4959 </category>
4960
4961 <category id="Heap_1_0" label="Heap (1.0)">
4962 <intro>
4963 <b>
4964 These functions and data types were introduced in the original
4965 <jvmti/> version 1.0 and have been superseded by more
4966 </b>
4967 <internallink id="Heap"><b>powerful and flexible versions</b></internallink>
4968 <b>
4969 which:
4970 </b>
4971 <ul>
4972 <li>
4973 <b>
4974 Allow access to primitive values (the value of Strings, arrays,
4975 and primitive fields)
4976 </b>
4977 </li>
4978 <li>
4979 <b>
4980 Allow the tag of the referrer to be set, thus enabling more
4981 efficient localized reference graph building
4982 </b>
4983 </li>
4984 <li>
4985 <b>
4986 Provide more extensive filtering abilities
4987 </b>
4988 </li>
4989 <li>
4990 <b>
4991 Are extensible, allowing their abilities to grow in future versions of <jvmti/>
4992 </b>
4993 </li>
4994 </ul>
4995 <p/>
4996 <b>Please use the </b>
4997 <internallink id="Heap"><b>current Heap functions</b></internallink>.
4998 <p/>
4999 <constants id="jvmtiHeapObjectFilter" label="Heap Object Filter Enumeration" kind="enum">
5000 <constant id="JVMTI_HEAP_OBJECT_TAGGED" num="1">
5001 Tagged objects only.
5002 </constant>
5003 <constant id="JVMTI_HEAP_OBJECT_UNTAGGED" num="2">
5004 Untagged objects only.
5005 </constant>
5006 <constant id="JVMTI_HEAP_OBJECT_EITHER" num="3">
5007 Either tagged or untagged objects.
5008 </constant>
5009 </constants>
5010
5011 <constants id="jvmtiHeapRootKind" label="Heap Root Kind Enumeration" kind="enum">
5012 <constant id="JVMTI_HEAP_ROOT_JNI_GLOBAL" num="1">
5013 JNI global reference.
5014 </constant>
5015 <constant id="JVMTI_HEAP_ROOT_SYSTEM_CLASS" num="2">
5016 System class.
5017 </constant>
5018 <constant id="JVMTI_HEAP_ROOT_MONITOR" num="3">
5019 Monitor.
5020 </constant>
5021 <constant id="JVMTI_HEAP_ROOT_STACK_LOCAL" num="4">
5022 Stack local.
5023 </constant>
5024 <constant id="JVMTI_HEAP_ROOT_JNI_LOCAL" num="5">
5025 JNI local reference.
5026 </constant>
5027 <constant id="JVMTI_HEAP_ROOT_THREAD" num="6">
5028 Thread.
5029 </constant>
5030 <constant id="JVMTI_HEAP_ROOT_OTHER" num="7">
5031 Other.
5032 </constant>
5033 </constants>
5034
5035 <constants id="jvmtiObjectReferenceKind" label="Object Reference Enumeration" kind="enum">
5036 <constant id="JVMTI_REFERENCE_CLASS" num="1">
5037 Reference from an object to its class.
5038 </constant>
5039 <constant id="JVMTI_REFERENCE_FIELD" num="2">
5040 Reference from an object to the value of one of its instance fields.
5041 For references of this kind the <code>referrer_index</code>
5042 parameter to the <internallink id="jvmtiObjectReferenceCallback">
5043 jvmtiObjectReferenceCallback</internallink> is the index of the
5044 the instance field. The index is based on the order of all the
5045 object's fields. This includes all fields of the directly declared
5046 static and instance fields in the class, and includes all fields (both
5047 public and private) fields declared in superclasses and superinterfaces.
5048 The index is thus calculated by summing the index of the field in the directly
5049 declared class (see <functionlink id="GetClassFields"/>), with the total
5050 number of fields (both public and private) declared in all superclasses
5051 and superinterfaces. The index starts at zero.
5052 </constant>
5053 <constant id="JVMTI_REFERENCE_ARRAY_ELEMENT" num="3">
5054 Reference from an array to one of its elements.
5055 For references of this kind the <code>referrer_index</code>
5056 parameter to the <internallink id="jvmtiObjectReferenceCallback">
5057 jvmtiObjectReferenceCallback</internallink> is the array index.
5058 </constant>
5059 <constant id="JVMTI_REFERENCE_CLASS_LOADER" num="4">
5060 Reference from a class to its class loader.
5061 </constant>
5062 <constant id="JVMTI_REFERENCE_SIGNERS" num="5">
5063 Reference from a class to its signers array.
5064 </constant>
5065 <constant id="JVMTI_REFERENCE_PROTECTION_DOMAIN" num="6">
5066 Reference from a class to its protection domain.
5067 </constant>
5068 <constant id="JVMTI_REFERENCE_INTERFACE" num="7">
5069 Reference from a class to one of its interfaces.
5070 </constant>
5071 <constant id="JVMTI_REFERENCE_STATIC_FIELD" num="8">
5072 Reference from a class to the value of one of its static fields.
5073 For references of this kind the <code>referrer_index</code>
5074 parameter to the <internallink id="jvmtiObjectReferenceCallback">
5075 jvmtiObjectReferenceCallback</internallink> is the index of the
5076 the static field. The index is based on the order of all the
5077 object's fields. This includes all fields of the directly declared
5078 static and instance fields in the class, and includes all fields (both
5079 public and private) fields declared in superclasses and superinterfaces.
5080 The index is thus calculated by summing the index of the field in the directly
5081 declared class (see <functionlink id="GetClassFields"/>), with the total
5082 number of fields (both public and private) declared in all superclasses
5083 and superinterfaces. The index starts at zero.
5084 Note: this definition differs from that in the <jvmti/> 1.0 Specification.
5085 <rationale>No known implementations used the 1.0 definition.</rationale>
5086 </constant>
5087 <constant id="JVMTI_REFERENCE_CONSTANT_POOL" num="9">
5088 Reference from a class to a resolved entry in the constant pool.
5089 For references of this kind the <code>referrer_index</code>
5090 parameter to the <internallink id="jvmtiObjectReferenceCallback">
5091 jvmtiObjectReferenceCallback</internallink> is the index into
5092 constant pool table of the class, starting at 1. See
5093 <vmspec chapter="4.4"/>.
5094 </constant>
5095 </constants>
5096
5097 <constants id="jvmtiIterationControl" label="Iteration Control Enumeration" kind="enum">
5098 <constant id="JVMTI_ITERATION_CONTINUE" num="1">
5099 Continue the iteration.
5100 If this is a reference iteration, follow the references of this object.
5101 </constant>
5102 <constant id="JVMTI_ITERATION_IGNORE" num="2">
5103 Continue the iteration.
5104 If this is a reference iteration, ignore the references of this object.
5105 </constant>
5106 <constant id="JVMTI_ITERATION_ABORT" num="0">
5107 Abort the iteration.
5108 </constant>
5109 </constants>
5110 </intro>
5111
5112 <callback id="jvmtiHeapObjectCallback">
5113 <enum>jvmtiIterationControl</enum>
5114 <synopsis>Heap Object Callback</synopsis>
5115 <description>
5116 Agent supplied callback function.
5117 Describes (but does not pass in) an object in the heap.
5118 <p/>
5119 Return value should be <code>JVMTI_ITERATION_CONTINUE</code> to continue iteration,
5120 or <code>JVMTI_ITERATION_ABORT</code> to stop iteration.
5121 <p/>
5122 See the <internallink id="heapCallbacks">heap callback
5123 function restrictions</internallink>.
5124 </description>
5125 <parameters>
5126 <param id="class_tag">
5127 <jlong/>
5128 <description>
5129 The tag of the class of object (zero if the class is not tagged).
5130 If the object represents a runtime class,
5131 the <code>class_tag</code> is the tag
5132 associated with <code>java.lang.Class</code>
5133 (zero if <code>java.lang.Class</code> is not tagged).
5134 </description>
5135 </param>
5136 <param id="size">
5137 <jlong/>
5138 <description>
5139 Size of the object (in bytes). See <functionlink id="GetObjectSize"/>.
5140 </description>
5141 </param>
5142 <param id="tag_ptr">
5143 <outptr><jlong/></outptr>
5144 <description>
5145 The object tag value, or zero if the object is not tagged.
5146 To set the tag value to be associated with the object
5147 the agent sets the <code>jlong</code> pointed to by the parameter.
5148 </description>
5149 </param>
5150 <param id="user_data">
5151 <outptr><void/></outptr>
5152 <description>
5153 The user supplied data that was passed into the iteration function.
5154 </description>
5155 </param>
5156 </parameters>
5157 </callback>
5158
5159 <callback id="jvmtiHeapRootCallback">
5160 <enum>jvmtiIterationControl</enum>
5161 <synopsis>Heap Root Object Callback</synopsis>
5162 <description>
5163 Agent supplied callback function.
5164 Describes (but does not pass in) an object that is a root for the purposes
5165 of garbage collection.
5166 <p/>
5167 Return value should be <code>JVMTI_ITERATION_CONTINUE</code> to continue iteration,
5168 <code>JVMTI_ITERATION_IGNORE</code> to continue iteration without pursuing
5169 references from referree object or <code>JVMTI_ITERATION_ABORT</code> to stop iteration.
5170 <p/>
5171 See the <internallink id="heapCallbacks">heap callback
5172 function restrictions</internallink>.
5173 </description>
5174 <parameters>
5175 <param id="root_kind">
5176 <enum>jvmtiHeapRootKind</enum>
5177 <description>
5178 The kind of heap root.
5179 </description>
5180 </param>
5181 <param id="class_tag">
5182 <jlong/>
5183 <description>
5184 The tag of the class of object (zero if the class is not tagged).
5185 If the object represents a runtime class, the <code>class_tag</code> is the tag
5186 associated with <code>java.lang.Class</code>
5187 (zero if <code>java.lang.Class</code> is not tagged).
5188 </description>
5189 </param>
5190 <param id="size">
5191 <jlong/>
5192 <description>
5193 Size of the object (in bytes). See <functionlink id="GetObjectSize"/>.
5194 </description>
5195 </param>
5196 <param id="tag_ptr">
5197 <outptr><jlong/></outptr>
5198 <description>
5199 The object tag value, or zero if the object is not tagged.
5200 To set the tag value to be associated with the object
5201 the agent sets the <code>jlong</code> pointed to by the parameter.
5202 </description>
5203 </param>
5204 <param id="user_data">
5205 <outptr><void/></outptr>
5206 <description>
5207 The user supplied data that was passed into the iteration function.
5208 </description>
5209 </param>
5210 </parameters>
5211 </callback>
5212
5213 <callback id="jvmtiStackReferenceCallback">
5214 <enum>jvmtiIterationControl</enum>
5215 <synopsis>Stack Reference Object Callback</synopsis>
5216 <description>
5217 Agent supplied callback function.
5218 Describes (but does not pass in) an object on the stack that is a root for
5219 the purposes of garbage collection.
5220 <p/>
5221 Return value should be <code>JVMTI_ITERATION_CONTINUE</code> to continue iteration,
5222 <code>JVMTI_ITERATION_IGNORE</code> to continue iteration without pursuing
5223 references from referree object or <code>JVMTI_ITERATION_ABORT</code> to stop iteration.
5224 <p/>
5225 See the <internallink id="heapCallbacks">heap callback
5226 function restrictions</internallink>.
5227 </description>
5228 <parameters>
5229 <param id="root_kind">
5230 <enum>jvmtiHeapRootKind</enum>
5231 <description>
5232 The kind of root (either <code>JVMTI_HEAP_ROOT_STACK_LOCAL</code> or
5233 <code>JVMTI_HEAP_ROOT_JNI_LOCAL</code>).
5234 </description>
5235 </param>
5236 <param id="class_tag">
5237 <jlong/>
5238 <description>
5239 The tag of the class of object (zero if the class is not tagged).
5240 If the object represents a runtime class, the <code>class_tag</code> is the tag
5241 associated with <code>java.lang.Class</code>
5242 (zero if <code>java.lang.Class</code> is not tagged).
5243 </description>
5244 </param>
5245 <param id="size">
5246 <jlong/>
5247 <description>
5248 Size of the object (in bytes). See <functionlink id="GetObjectSize"/>.
5249 </description>
5250 </param>
5251 <param id="tag_ptr">
5252 <outptr><jlong/></outptr>
5253 <description>
5254 The object tag value, or zero if the object is not tagged.
5255 To set the tag value to be associated with the object
5256 the agent sets the <code>jlong</code> pointed to by the parameter.
5257 </description>
5258 </param>
5259 <param id="thread_tag">
5260 <jlong/>
5261 <description>
5262 The tag of the thread corresponding to this stack, zero if not tagged.
5263 </description>
5264 </param>
5265 <param id="depth">
5266 <jint/>
5267 <description>
5268 The depth of the frame.
5269 </description>
5270 </param>
5271 <param id="method">
5272 <jmethodID/>
5273 <description>
5274 The method executing in this frame.
5275 </description>
5276 </param>
5277 <param id="slot">
5278 <jint/>
5279 <description>
5280 The slot number.
5281 </description>
5282 </param>
5283 <param id="user_data">
5284 <outptr><void/></outptr>
5285 <description>
5286 The user supplied data that was passed into the iteration function.
5287 </description>
5288 </param>
5289 </parameters>
5290 </callback>
5291
5292 <callback id="jvmtiObjectReferenceCallback">
5293 <enum>jvmtiIterationControl</enum>
5294 <synopsis>Object Reference Callback</synopsis>
5295 <description>
5296 Agent supplied callback function.
5297 Describes a reference from an object (the referrer) to another object
5298 (the referree).
5299 <p/>
5300 Return value should be <code>JVMTI_ITERATION_CONTINUE</code> to continue iteration,
5301 <code>JVMTI_ITERATION_IGNORE</code> to continue iteration without pursuing
5302 references from referree object or <code>JVMTI_ITERATION_ABORT</code> to stop iteration.
5303 <p/>
5304 See the <internallink id="heapCallbacks">heap callback
5305 function restrictions</internallink>.
5306 </description>
5307 <parameters>
5308 <param id="reference_kind">
5309 <enum>jvmtiObjectReferenceKind</enum>
5310 <description>
5311 The type of reference.
5312 </description>
5313 </param>
5314 <param id="class_tag">
5315 <jlong/>
5316 <description>
5317 The tag of the class of referree object (zero if the class is not tagged).
5318 If the referree object represents a runtime class,
5319 the <code>class_tag</code> is the tag
5320 associated with <code>java.lang.Class</code>
5321 (zero if <code>java.lang.Class</code> is not tagged).
5322 </description>
5323 </param>
5324 <param id="size">
5325 <jlong/>
5326 <description>
5327 Size of the referree object (in bytes).
5328 See <functionlink id="GetObjectSize"/>.
5329 </description>
5330 </param>
5331 <param id="tag_ptr">
5332 <outptr><jlong/></outptr>
5333 <description>
5334 The referree object tag value, or zero if the object is not
5335 tagged.
5336 To set the tag value to be associated with the object
5337 the agent sets the <code>jlong</code> pointed to by the parameter.
5338 </description>
5339 </param>
5340 <param id="referrer_tag">
5341 <jlong/>
5342 <description>
5343 The tag of the referrer object, or zero if the referrer
5344 object is not tagged.
5345 </description>
5346 </param>
5347 <param id="referrer_index">
5348 <jint/>
5349 <description>
5350 For references of type <code>JVMTI_REFERENCE_FIELD</code> or
5351 <code>JVMTI_REFERENCE_STATIC_FIELD</code> the index
5352 of the field in the referrer object. The index is based on the
5353 order of all the object's fields - see <internallink
5354 id="JVMTI_REFERENCE_FIELD">JVMTI_REFERENCE_FIELD</internallink>
5355 or <internallink
5356 id="JVMTI_REFERENCE_STATIC_FIELD">JVMTI_REFERENCE_STATIC_FIELD
5357 </internallink> for further description.
5358 <p/>
5359 For references of type <code>JVMTI_REFERENCE_ARRAY_ELEMENT</code>
5360 the array index - see <internallink id="JVMTI_REFERENCE_ARRAY_ELEMENT">
5361 JVMTI_REFERENCE_ARRAY_ELEMENT</internallink> for further description.
5362 <p/>
5363 For references of type <code>JVMTI_REFERENCE_CONSTANT_POOL</code>
5364 the index into the constant pool of the class - see
5365 <internallink id="JVMTI_REFERENCE_CONSTANT_POOL">
5366 JVMTI_REFERENCE_CONSTANT_POOL</internallink> for further
5367 description.
5368 <p/>
5369 For references of other kinds the <code>referrer_index</code> is
5370 <code>-1</code>.
5371 </description>
5372 </param>
5373 <param id="user_data">
5374 <outptr><void/></outptr>
5375 <description>
5376 The user supplied data that was passed into the iteration function.
5377 </description>
5378 </param>
5379 </parameters>
5380 </callback>
5381
5382 <function id="IterateOverObjectsReachableFromObject" num="109">
5383 <synopsis>Iterate Over Objects Reachable From Object</synopsis>
5384 <description>
5385 This function iterates over all objects that are directly
5386 and indirectly reachable from the specified object.
5387 For each object <i>A</i> (known
5388 as the referrer) with a reference to object <i>B</i> the specified
5389 callback function is called to describe the object reference.
5390 The callback is called exactly once for each reference from a referrer;
5391 this is true even if there are reference cycles or multiple paths to
5392 the referrer.
5393 There may be more than one reference between a referrer and a referree,
5394 These may be distinguished by the
5395 <datalink id="jvmtiObjectReferenceCallback.reference_kind"></datalink> and
5396 <datalink id="jvmtiObjectReferenceCallback.referrer_index"></datalink>.
5397 The callback for an object will always occur after the callback for
5398 its referrer.
5399 <p/>
5400 See <functionlink id="FollowReferences"/> for the object
5401 references which are reported.
5402 <p/>
5403 During the execution of this function the state of the heap
5404 does not change: no objects are allocated, no objects are
5405 garbage collected, and the state of objects (including
5406 held values) does not change.
5407 As a result, threads executing Java
5408 programming language code, threads attempting to resume the
5409 execution of Java programming language code, and threads
5410 attempting to execute JNI functions are typically stalled.
5411 </description>
5412 <origin>new</origin>
5413 <capabilities>
5414 <required id="can_tag_objects"></required>
5415 </capabilities>
5416 <parameters>
5417 <param id="object">
5418 <jobject/>
5419 <description>
5420 The object
5421 </description>
5422 </param>
5423 <param id="object_reference_callback">
5424 <ptrtype>
5425 <struct>jvmtiObjectReferenceCallback</struct>
5426 </ptrtype>
5427 <description>
5428 The callback to be called to describe each
5429 object reference.
5430 </description>
5431 </param>
5432 <param id="user_data">
5433 <inbuf>
5434 <void/>
5435 <nullok><code>NULL</code> is passed as the user supplied data</nullok>
5436 </inbuf>
5437 <description>
5438 User supplied data to be passed to the callback.
5439 </description>
5440 </param>
5441 </parameters>
5442 <errors>
5443 </errors>
5444 </function>
5445
5446 <function id="IterateOverReachableObjects" num="110">
5447 <synopsis>Iterate Over Reachable Objects</synopsis>
5448 <description>
5449 This function iterates over the root objects and all objects that
5450 are directly and indirectly reachable from the root objects.
5451 The root objects comprise the set of system classes,
5452 JNI globals, references from thread stacks, and other objects used as roots
5453 for the purposes of garbage collection.
5454 <p/>
5455 For each root the <paramlink id="heap_root_callback"></paramlink>
5456 or <paramlink id="stack_ref_callback"></paramlink> callback is called.
5457 An object can be a root object for more than one reason and in that case
5458 the appropriate callback is called for each reason.
5459 <p/>
5460 For each object reference the <paramlink id="object_ref_callback"></paramlink>
5461 callback function is called to describe the object reference.
5462 The callback is called exactly once for each reference from a referrer;
5463 this is true even if there are reference cycles or multiple paths to
5464 the referrer.
5465 There may be more than one reference between a referrer and a referree,
5466 These may be distinguished by the
5467 <datalink id="jvmtiObjectReferenceCallback.reference_kind"></datalink> and
5468 <datalink id="jvmtiObjectReferenceCallback.referrer_index"></datalink>.
5469 The callback for an object will always occur after the callback for
5470 its referrer.
5471 <p/>
5472 See <functionlink id="FollowReferences"/> for the object
5473 references which are reported.
5474 <p/>
5475 Roots are always reported to the profiler before any object references
5476 are reported. In other words, the <paramlink id="object_ref_callback"></paramlink>
5477 callback will not be called until the appropriate callback has been called
5478 for all roots. If the <paramlink id="object_ref_callback"></paramlink> callback is
5479 specified as <code>NULL</code> then this function returns after
5480 reporting the root objects to the profiler.
5481 <p/>
5482 During the execution of this function the state of the heap
5483 does not change: no objects are allocated, no objects are
5484 garbage collected, and the state of objects (including
5485 held values) does not change.
5486 As a result, threads executing Java
5487 programming language code, threads attempting to resume the
5488 execution of Java programming language code, and threads
5489 attempting to execute JNI functions are typically stalled.
5490 </description>
5491 <origin>new</origin>
5492 <capabilities>
5493 <required id="can_tag_objects"></required>
5494 </capabilities>
5495 <parameters>
5496 <param id="heap_root_callback">
5497 <ptrtype>
5498 <struct>jvmtiHeapRootCallback</struct>
5499 <nullok>do not report heap roots</nullok>
5500 </ptrtype>
5501 <description>
5502 The callback function to be called for each heap root of type
5503 <code>JVMTI_HEAP_ROOT_JNI_GLOBAL</code>,
5504 <code>JVMTI_HEAP_ROOT_SYSTEM_CLASS</code>,
5505 <code>JVMTI_HEAP_ROOT_MONITOR</code>,
5506 <code>JVMTI_HEAP_ROOT_THREAD</code>, or
5507 <code>JVMTI_HEAP_ROOT_OTHER</code>.
5508 </description>
5509 </param>
5510 <param id="stack_ref_callback">
5511 <ptrtype>
5512 <struct>jvmtiStackReferenceCallback</struct>
5513 <nullok>do not report stack references</nullok>
5514 </ptrtype>
5515 <description>
5516 The callback function to be called for each heap root of
5517 <code>JVMTI_HEAP_ROOT_STACK_LOCAL</code> or
5518 <code>JVMTI_HEAP_ROOT_JNI_LOCAL</code>.
5519 </description>
5520 </param>
5521 <param id="object_ref_callback">
5522 <ptrtype>
5523 <struct>jvmtiObjectReferenceCallback</struct>
5524 <nullok>do not follow references from the root objects</nullok>
5525 </ptrtype>
5526 <description>
5527 The callback function to be called for each object reference.
5528 </description>
5529 </param>
5530 <param id="user_data">
5531 <inbuf>
5532 <void/>
5533 <nullok><code>NULL</code> is passed as the user supplied data</nullok>
5534 </inbuf>
5535 <description>
5536 User supplied data to be passed to the callback.
5537 </description>
5538 </param>
5539 </parameters>
5540 <errors>
5541 </errors>
5542 </function>
5543
5544 <function id="IterateOverHeap" num="111">
5545 <synopsis>Iterate Over Heap</synopsis>
5546 <description>
5547 Iterate over all objects in the heap. This includes both reachable and
5548 unreachable objects.
5549 <p/>
5550 The <paramlink id="object_filter"></paramlink> parameter indicates the
5551 objects for which the callback function is called. If this parameter
5552 is <code>JVMTI_HEAP_OBJECT_TAGGED</code> then the callback will only be
5553 called for every object that is tagged. If the parameter is
5554 <code>JVMTI_HEAP_OBJECT_UNTAGGED</code> then the callback will only be
5555 for objects that are not tagged. If the parameter
5556 is <code>JVMTI_HEAP_OBJECT_EITHER</code> then the callback will be
5557 called for every object in the heap, irrespective of whether it is
5558 tagged or not.
5559 <p/>
5560 During the execution of this function the state of the heap
5561 does not change: no objects are allocated, no objects are
5562 garbage collected, and the state of objects (including
5563 held values) does not change.
5564 As a result, threads executing Java
5565 programming language code, threads attempting to resume the
5566 execution of Java programming language code, and threads
5567 attempting to execute JNI functions are typically stalled.
5568 </description>
5569 <origin>new</origin>
5570 <capabilities>
5571 <required id="can_tag_objects"></required>
5572 </capabilities>
5573 <parameters>
5574 <param id="object_filter">
5575 <enum>jvmtiHeapObjectFilter</enum>
5576 <description>
5577 Indicates the objects for which the callback function is called.
5578 </description>
5579 </param>
5580 <param id="heap_object_callback">
5581 <ptrtype>
5582 <struct>jvmtiHeapObjectCallback</struct>
5583 </ptrtype>
5584 <description>
5585 The iterator function to be called for each
5586 object matching the <paramlink id="object_filter"/>.
5587 </description>
5588 </param>
5589 <param id="user_data">
5590 <inbuf>
5591 <void/>
5592 <nullok><code>NULL</code> is passed as the user supplied data</nullok>
5593 </inbuf>
5594 <description>
5595 User supplied data to be passed to the callback.
5596 </description>
5597 </param>
5598 </parameters>
5599 <errors>
5600 </errors>
5601 </function>
5602
5603 <function id="IterateOverInstancesOfClass" num="112">
5604 <synopsis>Iterate Over Instances Of Class</synopsis>
5605 <description>
5606 Iterate over all objects in the heap that are instances of the specified class.
5607 This includes direct instances of the specified class and
5608 instances of all subclasses of the specified class.
5609 This includes both reachable and unreachable objects.
5610 <p/>
5611 The <paramlink id="object_filter"></paramlink> parameter indicates the
5612 objects for which the callback function is called. If this parameter
5613 is <code>JVMTI_HEAP_OBJECT_TAGGED</code> then the callback will only be
5614 called for every object that is tagged. If the parameter is
5615 <code>JVMTI_HEAP_OBJECT_UNTAGGED</code> then the callback will only be
5616 called for objects that are not tagged. If the parameter
5617 is <code>JVMTI_HEAP_OBJECT_EITHER</code> then the callback will be
5618 called for every object in the heap, irrespective of whether it is
5619 tagged or not.
5620 <p/>
5621 During the execution of this function the state of the heap
5622 does not change: no objects are allocated, no objects are
5623 garbage collected, and the state of objects (including
5624 held values) does not change.
5625 As a result, threads executing Java
5626 programming language code, threads attempting to resume the
5627 execution of Java programming language code, and threads
5628 attempting to execute JNI functions are typically stalled.
5629 </description>
5630 <origin>new</origin>
5631 <capabilities>
5632 <required id="can_tag_objects"></required>
5633 </capabilities>
5634 <parameters>
5635 <param id="klass">
5636 <jclass/>
5637 <description>
5638 Iterate over objects of this class only.
5639 </description>
5640 </param>
5641 <param id="object_filter">
5642 <enum>jvmtiHeapObjectFilter</enum>
5643 <description>
5644 Indicates the objects for which the callback function is called.
5645 </description>
5646 </param>
5647 <param id="heap_object_callback">
5648 <ptrtype>
5649 <struct>jvmtiHeapObjectCallback</struct>
5650 </ptrtype>
5651 <description>
5652 The iterator function to be called for each
5653 <paramlink id="klass"/> instance matching
5654 the <paramlink id="object_filter"/>.
5655 </description>
5656 </param>
5657 <param id="user_data">
5658 <inbuf>
5659 <void/>
5660 <nullok><code>NULL</code> is passed as the user supplied data</nullok>
5661 </inbuf>
5662 <description>
5663 User supplied data to be passed to the callback.
5664 </description>
5665 </param>
5666 </parameters>
5667 <errors>
5668 </errors>
5669 </function>
5670
5671 </category>
5672
5673 <category id="local" label="Local Variable">
5674
5675 <intro>
5676 These functions are used to retrieve or set the value of a local variable.
5677 The variable is identified by the depth of the frame containing its
5678 value and the variable's slot number within that frame.
5679 The mapping of variables to
5680 slot numbers can be obtained with the function
5681 <functionlink id="GetLocalVariableTable"></functionlink>.
5682 </intro>
5683
5684 <function id="GetLocalObject" num="21">
5685 <synopsis>Get Local Variable - Object</synopsis>
5686 <description>
5687 This function can be used to retrieve the value of a local
5688 variable whose type is <code>Object</code> or a subclass of <code>Object</code>.
5689 </description>
5690 <origin>jvmdi</origin>
5691 <capabilities>
5692 <required id="can_access_local_variables"></required>
5693 </capabilities>
5694 <parameters>
5695 <param id="thread">
5696 <jthread null="current" frame="frame"/>
5697 <description>
5698 The thread of the frame containing the variable's value.
5699 </description>
5700 </param>
5701 <param id="depth">
5702 <jframeID thread="thread"/>
5703 <description>
5704 The depth of the frame containing the variable's value.
5705 </description>
5706 </param>
5707 <param id="slot">
5708 <jint/>
5709 <description>
5710 The variable's slot number.
5711 </description>
5712 </param>
5713 <param id="value_ptr">
5714 <outptr><jobject/></outptr>
5715 <description>
5716 On return, points to the variable's value.
5717 </description>
5718 </param>
5719 </parameters>
5720 <errors>
5721 <error id="JVMTI_ERROR_INVALID_SLOT">
5722 Invalid <code>slot</code>.
5723 </error>
5724 <error id="JVMTI_ERROR_TYPE_MISMATCH">
5725 The variable type is not
5726 <code>Object</code> or a subclass of <code>Object</code>.
5727 </error>
5728 <error id="JVMTI_ERROR_OPAQUE_FRAME">
5729 Not a visible frame
5730 </error>
5731 </errors>
5732 </function>
5733
5734 <function id="GetLocalInstance" num="155" since="1.2">
5735 <synopsis>Get Local Instance</synopsis>
5736 <description>
5737 This function can be used to retrieve the value of the local object
5738 variable at slot 0 (the "<code>this</code>" object) from non-static
5739 frames. This function can retrieve the "<code>this</code>" object from
5740 native method frames, whereas <code>GetLocalObject()</code> would
5741 return <code>JVMTI_ERROR_OPAQUE_FRAME</code> in those cases.
5742 </description>
5743 <origin>new</origin>
5744 <capabilities>
5745 <required id="can_access_local_variables"></required>
5746 </capabilities>
5747 <parameters>
5748 <param id="thread">
5749 <jthread null="current" frame="frame"/>
5750 <description>
5751 The thread of the frame containing the variable's value.
5752 </description>
5753 </param>
5754 <param id="depth">
5755 <jframeID thread="thread"/>
5756 <description>
5757 The depth of the frame containing the variable's value.
5758 </description>
5759 </param>
5760 <param id="value_ptr">
5761 <outptr><jobject/></outptr>
5762 <description>
5763 On return, points to the variable's value.
5764 </description>
5765 </param>
5766 </parameters>
5767 <errors>
5768 <error id="JVMTI_ERROR_INVALID_SLOT">
5769 If the specified frame is a static method frame.
5770 </error>
5771 </errors>
5772 </function>
5773 <function id="GetLocalInt" num="22">
5774 <synopsis>Get Local Variable - Int</synopsis>
5775 <description>
5776 This function can be used to retrieve the value of a local
5777 variable whose type is <code>int</code>,
5778 <code>short</code>, <code>char</code>, <code>byte</code>, or
5779 <code>boolean</code>.
5780 </description>
5781 <origin>jvmdi</origin>
5782 <capabilities>
5783 <required id="can_access_local_variables"></required>
5784 </capabilities>
5785 <parameters>
5786 <param id="thread">
5787 <jthread null="current" frame="frame"/>
5788 <description>
5789 The thread of the frame containing the variable's value.
5790 </description>
5791 </param>
5792 <param id="depth">
5793 <jframeID thread="thread"/>
5794 <description>
5795 The depth of the frame containing the variable's value.
5796 </description>
5797 </param>
5798 <param id="slot">
5799 <jint/>
5800 <description>
5801 The variable's slot number.
5802 </description>
5803 </param>
5804 <param id="value_ptr">
5805 <outptr><jint/></outptr>
5806 <description>
5807 On return, points to the variable's value.
5808 </description>
5809 </param>
5810 </parameters>
5811 <errors>
5812 <error id="JVMTI_ERROR_INVALID_SLOT">
5813 Invalid <code>slot</code>.
5814 </error>
5815 <error id="JVMTI_ERROR_TYPE_MISMATCH">
5816 The variable type is not
5817 <code>int</code>, <code>short</code>,
5818 <code>char</code>, <code>byte</code>, or
5819 <code>boolean</code>.
5820 </error>
5821 <error id="JVMTI_ERROR_OPAQUE_FRAME">
5822 Not a visible frame
5823 </error>
5824 </errors>
5825 </function>
5826
5827 <function id="GetLocalLong" num="23">
5828 <synopsis>Get Local Variable - Long</synopsis>
5829 <description>
5830 This function can be used to retrieve the value of a local
5831 variable whose type is <code>long</code>.
5832 </description>
5833 <origin>jvmdi</origin>
5834 <capabilities>
5835 <required id="can_access_local_variables"></required>
5836 </capabilities>
5837 <parameters>
5838 <param id="thread">
5839 <jthread null="current" frame="frame"/>
5840 <description>
5841 The thread of the frame containing the variable's value.
5842 </description>
5843 </param>
5844 <param id="depth">
5845 <jframeID thread="thread"/>
5846 <description>
5847 The depth of the frame containing the variable's value.
5848 </description>
5849 </param>
5850 <param id="slot">
5851 <jint/>
5852 <description>
5853 The variable's slot number.
5854 </description>
5855 </param>
5856 <param id="value_ptr">
5857 <outptr><jlong/></outptr>
5858 <description>
5859 On return, points to the variable's value.
5860 </description>
5861 </param>
5862 </parameters>
5863 <errors>
5864 <error id="JVMTI_ERROR_INVALID_SLOT">
5865 Invalid <code>slot</code>.
5866 </error>
5867 <error id="JVMTI_ERROR_TYPE_MISMATCH">
5868 The variable type is not <code>long</code>.
5869 </error>
5870 <error id="JVMTI_ERROR_OPAQUE_FRAME">
5871 Not a visible frame
5872 </error>
5873 </errors>
5874 </function>
5875
5876 <function id="GetLocalFloat" num="24">
5877 <synopsis>Get Local Variable - Float</synopsis>
5878 <description>
5879 This function can be used to retrieve the value of a local
5880 variable whose type is <code>float</code>.
5881 </description>
5882 <origin>jvmdi</origin>
5883 <capabilities>
5884 <required id="can_access_local_variables"></required>
5885 </capabilities>
5886 <parameters>
5887 <param id="thread">
5888 <jthread null="current" frame="frame"/>
5889 <description>
5890 The thread of the frame containing the variable's value.
5891 </description>
5892 </param>
5893 <param id="depth">
5894 <jframeID thread="thread"/>
5895 <description>
5896 The depth of the frame containing the variable's value.
5897 </description>
5898 </param>
5899 <param id="slot">
5900 <jint/>
5901 <description>
5902 The variable's slot number.
5903 </description>
5904 </param>
5905 <param id="value_ptr">
5906 <outptr><jfloat/></outptr>
5907 <description>
5908 On return, points to the variable's value.
5909 </description>
5910 </param>
5911 </parameters>
5912 <errors>
5913 <error id="JVMTI_ERROR_INVALID_SLOT">
5914 Invalid <code>slot</code>.
5915 </error>
5916 <error id="JVMTI_ERROR_TYPE_MISMATCH">
5917 The variable type is not <code>float</code>.
5918 </error>
5919 <error id="JVMTI_ERROR_OPAQUE_FRAME">
5920 Not a visible frame
5921 </error>
5922 </errors>
5923 </function>
5924
5925 <function id="GetLocalDouble" num="25">
5926 <synopsis>Get Local Variable - Double</synopsis>
5927 <description>
5928 This function can be used to retrieve the value of a local
5929 variable whose type is <code>long</code>.
5930 </description>
5931 <origin>jvmdi</origin>
5932 <capabilities>
5933 <required id="can_access_local_variables"></required>
5934 </capabilities>
5935 <parameters>
5936 <param id="thread">
5937 <jthread null="current" frame="frame"/>
5938 <description>
5939 The thread of the frame containing the variable's value.
5940 </description>
5941 </param>
5942 <param id="depth">
5943 <jframeID thread="thread"/>
5944 <description>
5945 The depth of the frame containing the variable's value.
5946 </description>
5947 </param>
5948 <param id="slot">
5949 <jint/>
5950 <description>
5951 The variable's slot number.
5952 </description>
5953 </param>
5954 <param id="value_ptr">
5955 <outptr><jdouble/></outptr>
5956 <description>
5957 On return, points to the variable's value.
5958 </description>
5959 </param>
5960 </parameters>
5961 <errors>
5962 <error id="JVMTI_ERROR_INVALID_SLOT">
5963 Invalid <code>slot</code>.
5964 </error>
5965 <error id="JVMTI_ERROR_TYPE_MISMATCH">
5966 The variable type is not <code>double</code>.
5967 </error>
5968 <error id="JVMTI_ERROR_OPAQUE_FRAME">
5969 Not a visible frame
5970 </error>
5971 </errors>
5972 </function>
5973
5974 <function id="SetLocalObject" num="26">
5975 <synopsis>Set Local Variable - Object</synopsis>
5976 <description>
5977 This function can be used to set the value of a local
5978 variable whose type is <code>Object</code> or a subclass of <code>Object</code>.
5979 </description>
5980 <origin>jvmdi</origin>
5981 <capabilities>
5982 <required id="can_access_local_variables"></required>
5983 </capabilities>
5984 <parameters>
5985 <param id="thread">
5986 <jthread null="current" frame="frame"/>
5987 <description>
5988 The thread of the frame containing the variable's value.
5989 </description>
5990 </param>
5991 <param id="depth">
5992 <jframeID thread="thread"/>
5993 <description>
5994 The depth of the frame containing the variable's value.
5995 </description>
5996 </param>
5997 <param id="slot">
5998 <jint/>
5999 <description>
6000 The variable's slot number.
6001 </description>
6002 </param>
6003 <param id="value">
6004 <jobject/>
6005 <description>
6006 The new value for the variable.
6007 </description>
6008 </param>
6009 </parameters>
6010 <errors>
6011 <error id="JVMTI_ERROR_INVALID_SLOT">
6012 Invalid <code>slot</code>.
6013 </error>
6014 <error id="JVMTI_ERROR_TYPE_MISMATCH">
6015 The variable type is not
6016 <code>Object</code> or a subclass of <code>Object</code>.
6017 </error>
6018 <error id="JVMTI_ERROR_TYPE_MISMATCH">
6019 The supplied <paramlink id="value"/> is not compatible
6020 with the variable type.
6021 </error>
6022 <error id="JVMTI_ERROR_OPAQUE_FRAME">
6023 Not a visible frame
6024 </error>
6025 </errors>
6026 </function>
6027
6028 <function id="SetLocalInt" num="27">
6029 <synopsis>Set Local Variable - Int</synopsis>
6030 <description>
6031 This function can be used to set the value of a local
6032 variable whose type is <code>int</code>,
6033 <code>short</code>, <code>char</code>, <code>byte</code>, or
6034 <code>boolean</code>.
6035 </description>
6036 <origin>jvmdi</origin>
6037 <capabilities>
6038 <required id="can_access_local_variables"></required>
6039 </capabilities>
6040 <parameters>
6041 <param id="thread">
6042 <jthread null="current" frame="frame"/>
6043 <description>
6044 The thread of the frame containing the variable's value.
6045 </description>
6046 </param>
6047 <param id="depth">
6048 <jframeID thread="thread"/>
6049 <description>
6050 The depth of the frame containing the variable's value.
6051 </description>
6052 </param>
6053 <param id="slot">
6054 <jint/>
6055 <description>
6056 The variable's slot number.
6057 </description>
6058 </param>
6059 <param id="value">
6060 <jint/>
6061 <description>
6062 The new value for the variable.
6063 </description>
6064 </param>
6065 </parameters>
6066 <errors>
6067 <error id="JVMTI_ERROR_INVALID_SLOT">
6068 Invalid <code>slot</code>.
6069 </error>
6070 <error id="JVMTI_ERROR_TYPE_MISMATCH">
6071 The variable type is not
6072 <code>int</code>, <code>short</code>,
6073 <code>char</code>, <code>byte</code>, or
6074 <code>boolean</code>.
6075 </error>
6076 <error id="JVMTI_ERROR_OPAQUE_FRAME">
6077 Not a visible frame
6078 </error>
6079 </errors>
6080 </function>
6081
6082 <function id="SetLocalLong" num="28">
6083 <synopsis>Set Local Variable - Long</synopsis>
6084 <description>
6085 This function can be used to set the value of a local
6086 variable whose type is <code>long</code>.
6087 </description>
6088 <origin>jvmdi</origin>
6089 <capabilities>
6090 <required id="can_access_local_variables"></required>
6091 </capabilities>
6092 <parameters>
6093 <param id="thread">
6094 <jthread null="current" frame="frame"/>
6095 <description>
6096 The thread of the frame containing the variable's value.
6097 </description>
6098 </param>
6099 <param id="depth">
6100 <jframeID thread="thread"/>
6101 <description>
6102 The depth of the frame containing the variable's value.
6103 </description>
6104 </param>
6105 <param id="slot">
6106 <jint/>
6107 <description>
6108 The variable's slot number.
6109 </description>
6110 </param>
6111 <param id="value">
6112 <jlong/>
6113 <description>
6114 The new value for the variable.
6115 </description>
6116 </param>
6117 </parameters>
6118 <errors>
6119 <error id="JVMTI_ERROR_INVALID_SLOT">
6120 Invalid <code>slot</code>.
6121 </error>
6122 <error id="JVMTI_ERROR_TYPE_MISMATCH">
6123 The variable type is not <code>long</code>.
6124 </error>
6125 <error id="JVMTI_ERROR_OPAQUE_FRAME">
6126 Not a visible frame
6127 </error>
6128 </errors>
6129 </function>
6130
6131 <function id="SetLocalFloat" num="29">
6132 <synopsis>Set Local Variable - Float</synopsis>
6133 <description>
6134 This function can be used to set the value of a local
6135 variable whose type is <code>float</code>.
6136 </description>
6137 <origin>jvmdi</origin>
6138 <capabilities>
6139 <required id="can_access_local_variables"></required>
6140 </capabilities>
6141 <parameters>
6142 <param id="thread">
6143 <jthread null="current" frame="frame"/>
6144 <description>
6145 The thread of the frame containing the variable's value.
6146 </description>
6147 </param>
6148 <param id="depth">
6149 <jframeID thread="thread"/>
6150 <description>
6151 The depth of the frame containing the variable's value.
6152 </description>
6153 </param>
6154 <param id="slot">
6155 <jint/>
6156 <description>
6157 The variable's slot number.
6158 </description>
6159 </param>
6160 <param id="value">
6161 <jfloat/>
6162 <description>
6163 The new value for the variable.
6164 </description>
6165 </param>
6166 </parameters>
6167 <errors>
6168 <error id="JVMTI_ERROR_INVALID_SLOT">
6169 Invalid <code>slot</code>.
6170 </error>
6171 <error id="JVMTI_ERROR_TYPE_MISMATCH">
6172 The variable type is not <code>float</code>.
6173 </error>
6174 <error id="JVMTI_ERROR_OPAQUE_FRAME">
6175 Not a visible frame
6176 </error>
6177 </errors>
6178 </function>
6179
6180 <function id="SetLocalDouble" num="30">
6181 <synopsis>Set Local Variable - Double</synopsis>
6182 <description>
6183 This function can be used to set the value of a local
6184 variable whose type is <code>double</code>.
6185 </description>
6186 <origin>jvmdi</origin>
6187 <capabilities>
6188 <required id="can_access_local_variables"></required>
6189 </capabilities>
6190 <parameters>
6191 <param id="thread">
6192 <jthread null="current" frame="frame"/>
6193 <description>
6194 The thread of the frame containing the variable's value.
6195 </description>
6196 </param>
6197 <param id="depth">
6198 <jframeID thread="thread"/>
6199 <description>
6200 The depth of the frame containing the variable's value.
6201 </description>
6202 </param>
6203 <param id="slot">
6204 <jint/>
6205 <description>
6206 The variable's slot number.
6207 </description>
6208 </param>
6209 <param id="value">
6210 <jdouble/>
6211 <description>
6212 The new value for the variable.
6213 </description>
6214 </param>
6215 </parameters>
6216 <errors>
6217 <error id="JVMTI_ERROR_INVALID_SLOT">
6218 Invalid <code>slot</code>.
6219 </error>
6220 <error id="JVMTI_ERROR_TYPE_MISMATCH">
6221 The variable type is not <code>double</code>.
6222 </error>
6223 <error id="JVMTI_ERROR_OPAQUE_FRAME">
6224 Not a visible frame
6225 </error>
6226 </errors>
6227 </function>
6228 </category>
6229
6230 <category id="breakpointCategory" label="Breakpoint">
6231
6232 <intro>
6233 </intro>
6234
6235 <function id="SetBreakpoint" num="38">
6236 <synopsis>Set Breakpoint</synopsis>
6237 <description>
6238 Set a breakpoint at the instruction indicated by
6239 <code>method</code> and <code>location</code>.
6240 An instruction can only have one breakpoint.
6241 <p/>
6242 Whenever the designated instruction is about to be executed, a
6243 <eventlink id="Breakpoint"></eventlink> event is generated.
6244 </description>
6245 <origin>jvmdi</origin>
6246 <capabilities>
6247 <required id="can_generate_breakpoint_events"></required>
6248 </capabilities>
6249 <parameters>
6250 <param id="klass">
6251 <jclass method="method"/>
6252 <description>
6253 The class in which to set the breakpoint
6254 </description>
6255 </param>
6256 <param id="method">
6257 <jmethodID class="klass"/>
6258 <description>
6259 The method in which to set the breakpoint
6260 </description>
6261 </param>
6262 <param id="location">
6263 <jlocation/>
6264 <description>
6265 the index of the instruction at which to set the breakpoint
6266
6267 </description>
6268 </param>
6269 </parameters>
6270 <errors>
6271 <error id="JVMTI_ERROR_DUPLICATE">
6272 The designated bytecode already has a breakpoint.
6273 </error>
6274 </errors>
6275 </function>
6276
6277 <function id="ClearBreakpoint" num="39">
6278 <synopsis>Clear Breakpoint</synopsis>
6279 <description>
6280 Clear the breakpoint at the bytecode indicated by
6281 <code>method</code> and <code>location</code>.
6282 </description>
6283 <origin>jvmdi</origin>
6284 <capabilities>
6285 <required id="can_generate_breakpoint_events"></required>
6286 </capabilities>
6287 <parameters>
6288 <param id="klass">
6289 <jclass method="method"/>
6290 <description>
6291 The class in which to clear the breakpoint
6292 </description>
6293 </param>
6294 <param id="method">
6295 <jmethodID class="klass"/>
6296 <description>
6297 The method in which to clear the breakpoint
6298 </description>
6299 </param>
6300 <param id="location">
6301 <jlocation/>
6302 <description>
6303 the index of the instruction at which to clear the breakpoint
6304 </description>
6305 </param>
6306 </parameters>
6307 <errors>
6308 <error id="JVMTI_ERROR_NOT_FOUND">
6309 There's no breakpoint at the designated bytecode.
6310 </error>
6311 </errors>
6312 </function>
6313
6314 </category>
6315
6316 <category id="fieldWatch" label="Watched Field">
6317
6318 <intro>
6319 </intro>
6320
6321 <function id="SetFieldAccessWatch" num="41">
6322 <synopsis>Set Field Access Watch</synopsis>
6323 <description>
6324 Generate a <eventlink id="FieldAccess"></eventlink> event
6325 when the field specified
6326 by <code>klass</code> and
6327 <code>field</code> is about to be accessed.
6328 An event will be generated for each access of the field
6329 until it is canceled with
6330 <functionlink id="ClearFieldAccessWatch"></functionlink>.
6331 Field accesses from Java programming language code or from JNI code are watched,
6332 fields modified by other means are not watched.
6333 Note that <jvmti/> users should be aware that their own field accesses
6334 will trigger the watch.
6335 A field can only have one field access watch set.
6336 Modification of a field is not considered an access--use
6337 <functionlink id="SetFieldModificationWatch"></functionlink>
6338 to monitor modifications.
6339 </description>
6340 <origin>jvmdi</origin>
6341 <capabilities>
6342 <required id="can_generate_field_access_events"></required>
6343 </capabilities>
6344 <parameters>
6345 <param id="klass">
6346 <jclass field="field"/>
6347 <description>
6348 The class containing the field to watch
6349 </description>
6350 </param>
6351 <param id="field">
6352 <jfieldID class="klass"/>
6353 <description>
6354 The field to watch
6355
6356 </description>
6357 </param>
6358 </parameters>
6359 <errors>
6360 <error id="JVMTI_ERROR_DUPLICATE">
6361 The designated field is already being watched for accesses.
6362 </error>
6363 </errors>
6364 </function>
6365
6366 <function id="ClearFieldAccessWatch" num="42">
6367 <synopsis>Clear Field Access Watch</synopsis>
6368 <description>
6369 Cancel a field access watch previously set by
6370 <functionlink id="SetFieldAccessWatch"></functionlink>, on the
6371 field specified
6372 by <code>klass</code> and
6373 <code>field</code>.
6374 </description>
6375 <origin>jvmdi</origin>
6376 <capabilities>
6377 <required id="can_generate_field_access_events"></required>
6378 </capabilities>
6379 <parameters>
6380 <param id="klass">
6381 <jclass field="field"/>
6382 <description>
6383 The class containing the field to watch
6384 </description>
6385 </param>
6386 <param id="field">
6387 <jfieldID class="klass"/>
6388 <description>
6389 The field to watch
6390
6391 </description>
6392 </param>
6393 </parameters>
6394 <errors>
6395 <error id="JVMTI_ERROR_NOT_FOUND">
6396 The designated field is not being watched for accesses.
6397 </error>
6398 </errors>
6399 </function>
6400
6401 <function id="SetFieldModificationWatch" num="43">
6402 <synopsis>Set Field Modification Watch</synopsis>
6403 <description>
6404 Generate a <eventlink id="FieldModification"></eventlink> event
6405 when the field specified
6406 by <code>klass</code> and
6407 <code>field</code> is about to be modified.
6408 An event will be generated for each modification of the field
6409 until it is canceled with
6410 <functionlink id="ClearFieldModificationWatch"></functionlink>.
6411 Field modifications from Java programming language code or from JNI code are watched,
6412 fields modified by other means are not watched.
6413 Note that <jvmti/> users should be aware that their own field modifications
6414 will trigger the watch.
6415 A field can only have one field modification watch set.
6416 </description>
6417 <origin>jvmdi</origin>
6418 <capabilities>
6419 <required id="can_generate_field_modification_events"></required>
6420 </capabilities>
6421 <parameters>
6422 <param id="klass">
6423 <jclass field="field"/>
6424 <description>
6425 The class containing the field to watch
6426 </description>
6427 </param>
6428 <param id="field">
6429 <jfieldID class="klass"/>
6430 <description>
6431 The field to watch
6432
6433 </description>
6434 </param>
6435 </parameters>
6436 <errors>
6437 <error id="JVMTI_ERROR_DUPLICATE">
6438 The designated field is already being watched for modifications.
6439 </error>
6440 </errors>
6441 </function>
6442
6443 <function id="ClearFieldModificationWatch" num="44">
6444 <synopsis>Clear Field Modification Watch</synopsis>
6445 <description>
6446
6447 Cancel a field modification watch previously set by
6448 <functionlink id="SetFieldModificationWatch"></functionlink>, on the
6449 field specified
6450 by <code>klass</code> and
6451 <code>field</code>.
6452 </description>
6453 <origin>jvmdi</origin>
6454 <capabilities>
6455 <required id="can_generate_field_modification_events"></required>
6456 </capabilities>
6457 <parameters>
6458 <param id="klass">
6459 <jclass field="field"/>
6460 <description>
6461 The class containing the field to watch
6462 </description>
6463 </param>
6464 <param id="field">
6465 <jfieldID class="klass"/>
6466 <description>
6467 The field to watch
6468
6469 </description>
6470 </param>
6471 </parameters>
6472 <errors>
6473 <error id="JVMTI_ERROR_NOT_FOUND">
6474 The designated field is not being watched for modifications.
6475 </error>
6476 </errors>
6477 </function>
6478 </category>
6479
6480 <category id="module" label="Module">
6481
6482 <intro>
6483 </intro>
6484
6485 <function id="GetAllModules" num="3" since="9">
6486 <synopsis>Get All Modules</synopsis>
6487 <description>
6488 Return an array of all modules loaded in the virtual machine.
6489 The array includes the unnamed module for each class loader.
6490 The number of modules in the array is returned via
6491 <code>module_count_ptr</code>, and the array itself via
6492 <code>modules_ptr</code>.
6493 <p/>
6494 </description>
6495 <origin>new</origin>
6496 <capabilities>
6497 </capabilities>
6498 <parameters>
6499 <param id="module_count_ptr">
6500 <outptr><jint/></outptr>
6501 <description>
6502 On return, points to the number of returned modules.
6503 </description>
6504 </param>
6505 <param id="modules_ptr">
6506 <allocbuf outcount="module_count_ptr"><jobject/></allocbuf>
6507 <description>
6508 On return, points to an array of references, one
6509 for each module.
6510 </description>
6511 </param>
6512 </parameters>
6513 <errors>
6514 </errors>
6515 </function>
6516
6517 <function id="GetNamedModule" num="40" since="9">
6518 <synopsis>Get Named Module</synopsis>
6519 <description>
6520 Return the <code>java.lang.Module</code> object for a named
6521 module defined to a class loader that contains a given package.
6522 The module is returned via <code>module_ptr</code>.
6523 <p/>
6524 If a named module is defined to the class loader and it
6525 contains the package then that named module is returned,
6526 otherwise <code>NULL</code> is returned.
6527 <p/>
6528 </description>
6529 <origin>new</origin>
6530 <capabilities>
6531 </capabilities>
6532 <parameters>
6533 <param id="class_loader">
6534 <ptrtype>
6535 <jobject/>
6536 <nullok>the bootstrap loader is assumed</nullok>
6537 </ptrtype>
6538 <description>
6539 A class loader.
6540 If the <code>class_loader</code> is not <code>NULL</code>
6541 or a subclass of <code>java.lang.ClassLoader</code>
6542 this function returns
6543 <errorlink id="JVMTI_ERROR_ILLEGAL_ARGUMENT"></errorlink>.
6544 </description>
6545 </param>
6546 <param id="package_name">
6547 <inbuf><char/></inbuf>
6548 <description>
6549 The name of the package, encoded as a
6550 <internallink id="mUTF">modified UTF-8</internallink> string.
6551 The package name is in internal form (JVMS 4.2.1);
6552 identifiers are separated by forward slashes rather than periods.
6553 </description>
6554 </param>
6555 <param id="module_ptr">
6556 <outptr><jobject/></outptr>
6557 <description>
6558 On return, points to a <code>java.lang.Module</code> object
6559 or points to <code>NULL</code>.
6560 </description>
6561 </param>
6562 </parameters>
6563 <errors>
6564 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
6565 If class loader is not <code>NULL</code> and is not a class loader object.
6566 </error>
6567 </errors>
6568 </function>
6569
6570 <function id="AddModuleReads" num="94" since="9">
6571 <synopsis>Add Module Reads</synopsis>
6572 <description>
6573 Update a module to read another module. This function is a no-op
6574 when <paramlink id="module"></paramlink> is an unnamed module.
6575 This function facilitates the instrumentation of code
6576 in named modules where that instrumentation requires
6577 expanding the set of modules that a module reads.
6578 </description>
6579 <origin>new</origin>
6580 <capabilities>
6581 </capabilities>
6582 <parameters>
6583 <param id="module">
6584 <ptrtype><jobject/></ptrtype>
6585 <description>
6586 The module to update.
6587 </description>
6588 </param>
6589 <param id="to_module">
6590 <ptrtype><jobject/></ptrtype>
6591 <description>
6592 The additional module to read.
6593 </description>
6594 </param>
6595 </parameters>
6596 <errors>
6597 <error id="JVMTI_ERROR_INVALID_MODULE">
6598 If <paramlink id="module"></paramlink> is not a module object.
6599 </error>
6600 <error id="JVMTI_ERROR_INVALID_MODULE">
6601 If <paramlink id="to_module"></paramlink> is not a module object.
6602 </error>
6603 <error id="JVMTI_ERROR_UNMODIFIABLE_MODULE">
6604 if the module cannot be modified.
6605 See <functionlink id="IsModifiableModule"/>.
6606 </error>
6607 </errors>
6608 </function>
6609
6610 <function id="AddModuleExports" num="95" since="9">
6611 <synopsis>Add Module Exports</synopsis>
6612 <description>
6613 Update a module to export a package to another module.
6614 This function is a no-op when <paramlink id="module"></paramlink>
6615 is an unnamed module or an open module.
6616 This function facilitates the instrumentation of code
6617 in named modules where that instrumentation requires
6618 expanding the set of packages that a module exports.
6619 </description>
6620 <origin>new</origin>
6621 <capabilities>
6622 </capabilities>
6623 <parameters>
6624 <param id="module">
6625 <ptrtype><jobject/></ptrtype>
6626 <description>
6627 The module to update.
6628 </description>
6629 </param>
6630 <param id="pkg_name">
6631 <inbuf><char/></inbuf>
6632 <description>
6633 The exported package name.
6634 </description>
6635 </param>
6636 <param id="to_module">
6637 <ptrtype><jobject/></ptrtype>
6638 <description>
6639 The module the package is exported to.
6640 If the <code>to_module</code> is not a subclass of
6641 <code>java.lang.Module</code> this function returns
6642 <errorlink id="JVMTI_ERROR_INVALID_MODULE"></errorlink>.
6643 </description>
6644 </param>
6645 </parameters>
6646 <errors>
6647 <error id="JVMTI_ERROR_INVALID_MODULE">
6648 If <paramlink id="module"></paramlink> is not a module object.
6649 </error>
6650 <error id="JVMTI_ERROR_INVALID_MODULE">
6651 If <paramlink id="to_module"></paramlink> is not a module object.
6652 </error>
6653 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
6654 If the package <paramlink id="pkg_name"></paramlink>
6655 does not belong to the module.
6656 </error>
6657 <error id="JVMTI_ERROR_UNMODIFIABLE_MODULE">
6658 if the module cannot be modified.
6659 See <functionlink id="IsModifiableModule"/>.
6660 </error>
6661 </errors>
6662 </function>
6663
6664 <function id="AddModuleOpens" num="96" since="9">
6665 <synopsis>Add Module Opens</synopsis>
6666 <description>
6667 Update a module to open a package to another module.
6668 This function is a no-op when <paramlink id="module"></paramlink>
6669 is an unnamed module or an open module.
6670 This function facilitates the instrumentation of code
6671 in modules where that instrumentation requires
6672 expanding the set of packages that a module opens to
6673 other modules.
6674 </description>
6675 <origin>new</origin>
6676 <capabilities>
6677 </capabilities>
6678 <parameters>
6679 <param id="module">
6680 <ptrtype><jobject/></ptrtype>
6681 <description>
6682 The module to update.
6683 </description>
6684 </param>
6685 <param id="pkg_name">
6686 <inbuf><char/></inbuf>
6687 <description>
6688 The package name of the package to open.
6689 </description>
6690 </param>
6691 <param id="to_module">
6692 <ptrtype><jobject/></ptrtype>
6693 <description>
6694 The module with the package to open.
6695 If the <code>to_module</code> is not a subclass of
6696 <code>java.lang.Module</code> this function returns
6697 <errorlink id="JVMTI_ERROR_INVALID_MODULE"></errorlink>.
6698 </description>
6699 </param>
6700 </parameters>
6701 <errors>
6702 <error id="JVMTI_ERROR_INVALID_MODULE">
6703 If <paramlink id="module"></paramlink> is not a module object.
6704 </error>
6705 <error id="JVMTI_ERROR_INVALID_MODULE">
6706 If <paramlink id="to_module"></paramlink> is not a module object.
6707 </error>
6708 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
6709 If the package <paramlink id="pkg_name"></paramlink>
6710 does not belong to the module.
6711 </error>
6712 <error id="JVMTI_ERROR_UNMODIFIABLE_MODULE">
6713 if the module cannot be modified.
6714 See <functionlink id="IsModifiableModule"/>.
6715 </error>
6716 </errors>
6717 </function>
6718
6719 <function id="AddModuleUses" num="97" since="9">
6720 <synopsis>Add Module Uses</synopsis>
6721 <description>
6722 Updates a module to add a service to the set of services that
6723 a module uses. This function is a no-op when the module
6724 is an unnamed module.
6725 This function facilitates the instrumentation of code
6726 in named modules where that instrumentation requires
6727 expanding the set of services that a module is using.
6728 </description>
6729 <origin>new</origin>
6730 <capabilities>
6731 </capabilities>
6732 <parameters>
6733 <param id="module">
6734 <ptrtype><jobject/></ptrtype>
6735 <description>
6736 The module to update.
6737 </description>
6738 </param>
6739 <param id="service">
6740 <ptrtype><jclass/></ptrtype>
6741 <description>
6742 The service to use.
6743 </description>
6744 </param>
6745 </parameters>
6746 <errors>
6747 <error id="JVMTI_ERROR_INVALID_MODULE">
6748 If <paramlink id="module"></paramlink> is not a module object.
6749 </error>
6750 <error id="JVMTI_ERROR_INVALID_CLASS">
6751 If <paramlink id="service"></paramlink> is not a class object.
6752 </error>
6753 <error id="JVMTI_ERROR_UNMODIFIABLE_MODULE">
6754 if the module cannot be modified.
6755 See <functionlink id="IsModifiableModule"/>.
6756 </error>
6757 </errors>
6758 </function>
6759
6760 <function id="AddModuleProvides" num="98" since="9">
6761 <synopsis>Add Module Provides</synopsis>
6762 <description>
6763 Updates a module to add a service to the set of services that
6764 a module provides. This function is a no-op when the module
6765 is an unnamed module.
6766 This function facilitates the instrumentation of code
6767 in named modules where that instrumentation requires
6768 changes to the services that are provided.
6769 </description>
6770 <origin>new</origin>
6771 <capabilities>
6772 </capabilities>
6773 <parameters>
6774 <param id="module">
6775 <ptrtype><jobject/></ptrtype>
6776 <description>
6777 The module to update.
6778 </description>
6779 </param>
6780 <param id="service">
6781 <ptrtype><jclass/></ptrtype>
6782 <description>
6783 The service to provide.
6784 </description>
6785 </param>
6786 <param id="impl_class">
6787 <ptrtype><jclass/></ptrtype>
6788 <description>
6789 The implementation class for the provided service.
6790 </description>
6791 </param>
6792 </parameters>
6793 <errors>
6794 <error id="JVMTI_ERROR_INVALID_MODULE">
6795 If <paramlink id="module"></paramlink> is not a module object.
6796 </error>
6797 <error id="JVMTI_ERROR_INVALID_CLASS">
6798 If <paramlink id="service"></paramlink> is not a class object.
6799 </error>
6800 <error id="JVMTI_ERROR_INVALID_CLASS">
6801 If <paramlink id="impl_class"></paramlink> is not a class object.
6802 </error>
6803 <error id="JVMTI_ERROR_UNMODIFIABLE_MODULE">
6804 if the module cannot be modified.
6805 See <functionlink id="IsModifiableModule"/>.
6806 </error>
6807 </errors>
6808 </function>
6809
6810 <function id="IsModifiableModule" num="99" since="9">
6811 <synopsis>Is Modifiable Module</synopsis>
6812 <description>
6813 Determines whether a module is modifiable.
6814 If a module is modifiable then this module can be updated with
6815 <functionlink id="AddModuleReads"/>, <functionlink id="AddModuleExports"/>,
6816 <functionlink id="AddModuleOpens"/>, <functionlink id="AddModuleUses"/>,
6817 and <functionlink id="AddModuleProvides"/>. If a module is not modifiable
6818 then the module can not be updated with these functions. The result of
6819 this function is always <code>JNI_TRUE</code> when called to determine
6820 if an unnamed module is modifiable.
6821 </description>
6822 <origin>new</origin>
6823 <capabilities>
6824 </capabilities>
6825 <parameters>
6826 <param id="module">
6827 <ptrtype><jobject/></ptrtype>
6828 <description>
6829 The module to query.
6830 </description>
6831 </param>
6832 <param id="is_modifiable_module_ptr">
6833 <outptr><jboolean/></outptr>
6834 <description>
6835 On return, points to the boolean result of this function.
6836 </description>
6837 </param>
6838 </parameters>
6839 <errors>
6840 <error id="JVMTI_ERROR_INVALID_MODULE">
6841 If <paramlink id="module"></paramlink> is not a module object.
6842 </error>
6843 </errors>
6844 </function>
6845
6846 </category>
6847
6848 <category id="class" label="Class">
6849
6850 <intro>
6851 </intro>
6852
6853 <function id="GetLoadedClasses" jkernel="yes" num="78">
6854 <synopsis>Get Loaded Classes</synopsis>
6855 <description>
6856 Return an array of all classes loaded in the virtual machine.
6857 The number of classes in the array is returned via
6858 <code>class_count_ptr</code>, and the array itself via
6859 <code>classes_ptr</code>.
6860 <p/>
6861 Array classes of all types (including arrays of primitive types) are
6862 included in the returned list. Primitive classes (for example,
6863 <code>java.lang.Integer.TYPE</code>) are <i>not</i> included in this list.
6864 </description>
6865 <origin>jvmdi</origin>
6866 <capabilities>
6867 </capabilities>
6868 <parameters>
6869 <param id="class_count_ptr">
6870 <outptr><jint/></outptr>
6871 <description>
6872 On return, points to the number of classes.
6873 </description>
6874 </param>
6875 <param id="classes_ptr">
6876 <allocbuf outcount="class_count_ptr"><jclass/></allocbuf>
6877 <description>
6878 On return, points to an array of references, one
6879 for each class.
6880 </description>
6881 </param>
6882 </parameters>
6883 <errors>
6884 </errors>
6885 </function>
6886
6887 <function id="GetClassLoaderClasses" jkernel="yes" num="79">
6888 <synopsis>Get Classloader Classes</synopsis>
6889 <description>
6890 Returns an array of those classes for which this class loader has
6891 been recorded as an initiating loader. Each
6892 class in the returned array was created by this class loader,
6893 either by defining it directly or by delegation to another class loader.
6894 See <vmspec chapter="5.3"/>.
6895 <p/>
6896 The number of classes in the array is returned via
6897 <code>class_count_ptr</code>, and the array itself via
6898 <code>classes_ptr</code>.
6899 </description>
6900 <origin>jvmdi</origin>
6901 <capabilities>
6902 </capabilities>
6903 <parameters>
6904 <param id="initiating_loader">
6905 <ptrtype>
6906 <jobject/>
6907 <nullok>the classes initiated by the bootstrap loader will be returned</nullok>
6908 </ptrtype>
6909 <description>
6910 An initiating class loader.
6911 </description>
6912 </param>
6913 <param id="class_count_ptr">
6914 <outptr><jint/></outptr>
6915 <description>
6916 On return, points to the number of classes.
6917 </description>
6918 </param>
6919 <param id="classes_ptr">
6920 <allocbuf outcount="class_count_ptr"><jclass/></allocbuf>
6921 <description>
6922 On return, points to an array of references, one
6923 for each class.
6924 </description>
6925 </param>
6926 </parameters>
6927 <errors>
6928 </errors>
6929 </function>
6930
6931 <function id="GetClassSignature" phase="start" num="48">
6932 <synopsis>Get Class Signature</synopsis>
6933 <description>
6934 For the class indicated by <code>klass</code>, return the
6935 <externallink id="jni/types.html#type-signatures">JNI
6936 type signature</externallink>
6937 and the generic signature of the class.
6938 For example, <code>java.util.List</code> is <code>"Ljava/util/List;"</code>
6939 and <code>int[]</code> is <code>"[I"</code>
6940 The returned name for primitive classes
6941 is the type signature character of the corresponding primitive type.
6942 For example, <code>java.lang.Integer.TYPE</code> is <code>"I"</code>.
6943 </description>
6944 <origin>jvmdiClone</origin>
6945 <capabilities>
6946 </capabilities>
6947 <parameters>
6948 <param id="klass">
6949 <jclass/>
6950 <description>
6951 The class to query.
6952 </description>
6953 </param>
6954 <param id="signature_ptr">
6955 <allocbuf>
6956 <char/>
6957 <nullok>the signature is not returned</nullok>
6958 </allocbuf>
6959 <description>
6960 On return, points to the JNI type signature of the class, encoded as a
6961 <internallink id="mUTF">modified UTF-8</internallink> string.
6962 </description>
6963 </param>
6964 <param id="generic_ptr">
6965 <allocbuf>
6966 <char/>
6967 <nullok>the generic signature is not returned</nullok>
6968 </allocbuf>
6969 <description>
6970 On return, points to the generic signature of the class, encoded as a
6971 <internallink id="mUTF">modified UTF-8</internallink> string.
6972 If there is no generic signature attribute for the class, then,
6973 on return, points to <code>NULL</code>.
6974 </description>
6975 </param>
6976 </parameters>
6977 <errors>
6978 </errors>
6979 </function>
6980
6981 <function id="GetClassStatus" phase="start" num="49">
6982 <synopsis>Get Class Status</synopsis>
6983 <description>
6984 Get the status of the class. Zero or more of the following bits can be
6985 set.
6986 <constants id="jvmtiClassStatus" label="Class Status Flags" kind="bits">
6987 <constant id="JVMTI_CLASS_STATUS_VERIFIED" num="1">
6988 Class bytecodes have been verified
6989 </constant>
6990 <constant id="JVMTI_CLASS_STATUS_PREPARED" num="2">
6991 Class preparation is complete
6992 </constant>
6993 <constant id="JVMTI_CLASS_STATUS_INITIALIZED" num="4">
6994 Class initialization is complete. Static initializer has been run.
6995 </constant>
6996 <constant id="JVMTI_CLASS_STATUS_ERROR" num="8">
6997 Error during initialization makes class unusable
6998 </constant>
6999 <constant id="JVMTI_CLASS_STATUS_ARRAY" num="16">
7000 Class is an array. If set, all other bits are zero.
7001 </constant>
7002 <constant id="JVMTI_CLASS_STATUS_PRIMITIVE" num="32">
7003 Class is a primitive class (for example, <code>java.lang.Integer.TYPE</code>).
7004 If set, all other bits are zero.
7005 </constant>
7006 </constants>
7007 </description>
7008 <origin>jvmdi</origin>
7009 <capabilities>
7010 </capabilities>
7011 <parameters>
7012 <param id="klass">
7013 <jclass/>
7014 <description>
7015 The class to query.
7016 </description>
7017 </param>
7018 <param id="status_ptr">
7019 <outptr><jint/></outptr>
7020 <description>
7021 On return, points to the current state of this class as one or
7022 more of the <internallink id="jvmtiClassStatus">class status flags</internallink>.
7023 </description>
7024 </param>
7025 </parameters>
7026 <errors>
7027 </errors>
7028 </function>
7029
7030 <function id="GetSourceFileName" phase="start" num="50">
7031 <synopsis>Get Source File Name</synopsis>
7032 <description>
7033 For the class indicated by <code>klass</code>, return the source file
7034 name via <code>source_name_ptr</code>. The returned string
7035 is a file name only and never contains a directory name.
7036 <p/>
7037 For primitive classes (for example, <code>java.lang.Integer.TYPE</code>)
7038 and for arrays this function returns
7039 <errorlink id="JVMTI_ERROR_ABSENT_INFORMATION"></errorlink>.
7040 </description>
7041 <origin>jvmdi</origin>
7042 <capabilities>
7043 <required id="can_get_source_file_name"></required>
7044 </capabilities>
7045 <parameters>
7046 <param id="klass">
7047 <jclass/>
7048 <description>
7049 The class to query.
7050 </description>
7051 </param>
7052 <param id="source_name_ptr">
7053 <allocbuf><char/></allocbuf>
7054 <description>
7055 On return, points to the class's source file name, encoded as a
7056 <internallink id="mUTF">modified UTF-8</internallink> string.
7057 </description>
7058 </param>
7059 </parameters>
7060 <errors>
7061 <error id="JVMTI_ERROR_ABSENT_INFORMATION">
7062 Class information does not include a source file name. This includes
7063 cases where the class is an array class or primitive class.
7064 </error>
7065 </errors>
7066 </function>
7067
7068 <function id="GetClassModifiers" phase="start" num="51">
7069 <synopsis>Get Class Modifiers</synopsis>
7070 <description>
7071 For the class indicated by <code>klass</code>, return the access
7072 flags
7073 via <code>modifiers_ptr</code>.
7074 Access flags are defined in <vmspec chapter="4"/>.
7075 <p/>
7076 If the class is an array class, then its public, private, and protected
7077 modifiers are the same as those of its component type. For arrays of
7078 primitives, this component type is represented by one of the primitive
7079 classes (for example, <code>java.lang.Integer.TYPE</code>).
7080 <p/>
7081 If the class is a primitive class, its public modifier is always true,
7082 and its protected and private modifiers are always false.
7083 <p/>
7084 If the class is an array class or a primitive class then its final
7085 modifier is always true and its interface modifier is always false.
7086 The values of its other modifiers are not determined by this specification.
7087
7088 </description>
7089 <origin>jvmdi</origin>
7090 <capabilities>
7091 </capabilities>
7092 <parameters>
7093 <param id="klass">
7094 <jclass/>
7095 <description>
7096 The class to query.
7097 </description>
7098 </param>
7099 <param id="modifiers_ptr">
7100 <outptr><jint/></outptr>
7101 <description>
7102 On return, points to the current access flags of this class.
7103
7104 </description>
7105 </param>
7106 </parameters>
7107 <errors>
7108 </errors>
7109 </function>
7110
7111 <function id="GetClassMethods" phase="start" num="52">
7112 <synopsis>Get Class Methods</synopsis>
7113 <description>
7114 For the class indicated by <code>klass</code>, return a count of
7115 methods via <code>method_count_ptr</code> and a list of
7116 method IDs via <code>methods_ptr</code>. The method list contains
7117 constructors and static initializers as well as true methods.
7118 Only directly declared methods are returned (not inherited methods).
7119 An empty method list is returned for array classes and primitive classes
7120 (for example, <code>java.lang.Integer.TYPE</code>).
7121 </description>
7122 <origin>jvmdi</origin>
7123 <capabilities>
7124 <capability id="can_maintain_original_method_order"/>
7125 </capabilities>
7126 <parameters>
7127 <param id="klass">
7128 <jclass/>
7129 <description>
7130 The class to query.
7131 </description>
7132 </param>
7133 <param id="method_count_ptr">
7134 <outptr><jint/></outptr>
7135 <description>
7136 On return, points to the number of methods declared in this class.
7137 </description>
7138 </param>
7139 <param id="methods_ptr">
7140 <allocbuf outcount="method_count_ptr"><jmethodID class="klass"/></allocbuf>
7141 <description>
7142 On return, points to the method ID array.
7143 </description>
7144 </param>
7145 </parameters>
7146 <errors>
7147 <error id="JVMTI_ERROR_CLASS_NOT_PREPARED">
7148 <paramlink id="klass"></paramlink> is not prepared.
7149 </error>
7150 </errors>
7151 </function>
7152
7153 <function id="GetClassFields" phase="start" num="53">
7154 <synopsis>Get Class Fields</synopsis>
7155 <description>
7156 For the class indicated by <code>klass</code>, return a count of fields
7157 via <code>field_count_ptr</code> and a list of field IDs via
7158 <code>fields_ptr</code>.
7159 Only directly declared fields are returned (not inherited fields).
7160 Fields are returned in the order they occur in the class file.
7161 An empty field list is returned for array classes and primitive classes
7162 (for example, <code>java.lang.Integer.TYPE</code>).
7163 Use JNI to determine the length of an array.
7164 </description>
7165 <origin>jvmdi</origin>
7166 <capabilities>
7167 </capabilities>
7168 <parameters>
7169 <param id="klass">
7170 <jclass/>
7171 <description>
7172 The class to query.
7173 </description>
7174 </param>
7175 <param id="field_count_ptr">
7176 <outptr><jint/></outptr>
7177 <description>
7178 On return, points to the number of fields declared in this class.
7179 </description>
7180 </param>
7181 <param id="fields_ptr">
7182 <allocbuf outcount="field_count_ptr"><jfieldID/></allocbuf>
7183 <description>
7184 On return, points to the field ID array.
7185 </description>
7186 </param>
7187 </parameters>
7188 <errors>
7189 <error id="JVMTI_ERROR_CLASS_NOT_PREPARED">
7190 <paramlink id="klass"></paramlink> is not prepared.
7191 </error>
7192 </errors>
7193 </function>
7194
7195 <function id="GetImplementedInterfaces" phase="start" num="54">
7196 <synopsis>Get Implemented Interfaces</synopsis>
7197 <description>
7198 Return the direct super-interfaces of this class. For a class, this
7199 function returns the interfaces declared in its <code>implements</code>
7200 clause. For an interface, this function returns the interfaces declared in
7201 its <code>extends</code> clause.
7202 An empty interface list is returned for array classes and primitive classes
7203 (for example, <code>java.lang.Integer.TYPE</code>).
7204 </description>
7205 <origin>jvmdi</origin>
7206 <capabilities>
7207 </capabilities>
7208 <parameters>
7209 <param id="klass">
7210 <jclass/>
7211 <description>
7212 The class to query.
7213 </description>
7214 </param>
7215 <param id="interface_count_ptr">
7216 <outptr><jint/></outptr>
7217 <description>
7218 On return, points to the number of interfaces.
7219 </description>
7220 </param>
7221 <param id="interfaces_ptr">
7222 <allocbuf outcount="interface_count_ptr"><jclass/></allocbuf>
7223 <description>
7224 On return, points to the interface array.
7225 </description>
7226 </param>
7227 </parameters>
7228 <errors>
7229 <error id="JVMTI_ERROR_CLASS_NOT_PREPARED">
7230 <paramlink id="klass"></paramlink> is not prepared.
7231 </error>
7232 </errors>
7233 </function>
7234
7235 <function id="GetClassVersionNumbers" phase="start" num="145" since="1.1">
7236 <synopsis>Get Class Version Numbers</synopsis>
7237 <description>
7238 For the class indicated by <code>klass</code>,
7239 return the minor and major version numbers,
7240 as defined in
7241 <vmspec chapter="4"/>.
7242 </description>
7243 <origin>new</origin>
7244 <capabilities>
7245 </capabilities>
7246 <parameters>
7247 <param id="klass">
7248 <jclass/>
7249 <description>
7250 The class to query.
7251 </description>
7252 </param>
7253 <param id="minor_version_ptr">
7254 <outptr><jint/></outptr>
7255 <description>
7256 On return, points to the value of the
7257 <code>minor_version</code> item of the
7258 Class File Format.
7259 Note: to be consistent with the Class File Format,
7260 the minor version number is the first parameter.
7261 </description>
7262 </param>
7263 <param id="major_version_ptr">
7264 <outptr><jint/></outptr>
7265 <description>
7266 On return, points to the value of the
7267 <code>major_version</code> item of the
7268 Class File Format.
7269 </description>
7270 </param>
7271 </parameters>
7272 <errors>
7273 <error id="JVMTI_ERROR_ABSENT_INFORMATION">
7274 The class is a primitive or array class.
7275 </error>
7276 </errors>
7277 </function>
7278
7279 <function id="GetConstantPool" phase="start" num="146" since="1.1">
7280 <synopsis>Get Constant Pool</synopsis>
7281 <description>
7282 For the class indicated by <code>klass</code>,
7283 return the raw bytes of the constant pool in the format of the
7284 <code>constant_pool</code> item of
7285 <vmspec chapter="4"/>.
7286 The format of the constant pool may differ between versions
7287 of the Class File Format, so, the
7288 <functionlink id="GetClassVersionNumbers">minor and major
7289 class version numbers</functionlink> should be checked for
7290 compatibility.
7291 <p/>
7292 The returned constant pool might not have the same layout or
7293 contents as the constant pool in the defining class file.
7294 The constant pool returned by GetConstantPool() may have
7295 more or fewer entries than the defining constant pool.
7296 Entries may be in a different order.
7297 The constant pool returned by GetConstantPool() will match the
7298 constant pool used by
7299 <functionlink id="GetBytecodes">GetBytecodes()</functionlink>.
7300 That is, the bytecodes returned by GetBytecodes() will have
7301 constant pool indices which refer to constant pool entries returned
7302 by GetConstantPool().
7303 Note that since <functionlink id="RetransformClasses"/>
7304 and <functionlink id="RedefineClasses"/> can change
7305 the constant pool, the constant pool returned by this function
7306 can change accordingly. Thus, the correspondence between
7307 GetConstantPool() and GetBytecodes() does not hold if there
7308 is an intervening class retransformation or redefinition.
7309 The value of a constant pool entry used by a given bytecode will
7310 match that of the defining class file (even if the indices don't match).
7311 Constant pool entries which are not used directly or indirectly by
7312 bytecodes (for example, UTF-8 strings associated with annotations) are
7313 not required to exist in the returned constant pool.
7314 </description>
7315 <origin>new</origin>
7316 <capabilities>
7317 <required id="can_get_constant_pool"></required>
7318 </capabilities>
7319 <parameters>
7320 <param id="klass">
7321 <jclass/>
7322 <description>
7323 The class to query.
7324 </description>
7325 </param>
7326 <param id="constant_pool_count_ptr">
7327 <outptr><jint/></outptr>
7328 <description>
7329 On return, points to the number of entries
7330 in the constant pool table plus one.
7331 This corresponds to the <code>constant_pool_count</code>
7332 item of the Class File Format.
7333 </description>
7334 </param>
7335 <param id="constant_pool_byte_count_ptr">
7336 <outptr><jint/></outptr>
7337 <description>
7338 On return, points to the number of bytes
7339 in the returned raw constant pool.
7340 </description>
7341 </param>
7342 <param id="constant_pool_bytes_ptr">
7343 <allocbuf outcount="constant_pool_byte_count_ptr"><uchar/></allocbuf>
7344 <description>
7345 On return, points to the raw constant pool, that is the bytes
7346 defined by the <code>constant_pool</code> item of the
7347 Class File Format
7348 </description>
7349 </param>
7350 </parameters>
7351 <errors>
7352 <error id="JVMTI_ERROR_ABSENT_INFORMATION">
7353 The class is a primitive or array class.
7354 </error>
7355 </errors>
7356 </function>
7357
7358 <function id="IsInterface" phase="start" num="55">
7359 <synopsis>Is Interface</synopsis>
7360 <description>
7361 Determines whether a class object reference represents an interface.
7362 The <code>jboolean</code> result is
7363 <code>JNI_TRUE</code> if the "class" is actually an interface,
7364 <code>JNI_FALSE</code> otherwise.
7365 </description>
7366 <origin>jvmdi</origin>
7367 <capabilities>
7368 </capabilities>
7369 <parameters>
7370 <param id="klass">
7371 <jclass/>
7372 <description>
7373 The class to query.
7374 </description>
7375 </param>
7376 <param id="is_interface_ptr">
7377 <outptr><jboolean/></outptr>
7378 <description>
7379 On return, points to the boolean result of this function.
7380
7381 </description>
7382 </param>
7383 </parameters>
7384 <errors>
7385 </errors>
7386 </function>
7387
7388 <function id="IsArrayClass" phase="start" num="56">
7389 <synopsis>Is Array Class</synopsis>
7390 <description>
7391 Determines whether a class object reference represents an array.
7392 The <code>jboolean</code> result is
7393 <code>JNI_TRUE</code> if the class is an array,
7394 <code>JNI_FALSE</code> otherwise.
7395 </description>
7396 <origin>jvmdi</origin>
7397 <capabilities>
7398 </capabilities>
7399 <parameters>
7400 <param id="klass">
7401 <jclass/>
7402 <description>
7403 The class to query.
7404 </description>
7405 </param>
7406 <param id="is_array_class_ptr">
7407 <outptr><jboolean/></outptr>
7408 <description>
7409 On return, points to the boolean result of this function.
7410
7411 </description>
7412 </param>
7413 </parameters>
7414 <errors>
7415 </errors>
7416 </function>
7417
7418 <function id="IsModifiableClass" jkernel="yes" phase="start" num="45" since="1.1">
7419 <synopsis>Is Modifiable Class</synopsis>
7420 <description>
7421 Determines whether a class is modifiable.
7422 If a class is modifiable (<paramlink id="is_modifiable_class_ptr"/>
7423 returns <code>JNI_TRUE</code>) the class can be
7424 redefined with <functionlink id="RedefineClasses"/> (assuming
7425 the agent possesses the
7426 <fieldlink id="can_redefine_classes" struct="jvmtiCapabilities"/>
7427 capability) or
7428 retransformed with <functionlink id="RetransformClasses"/> (assuming
7429 the agent possesses the
7430 <fieldlink id="can_retransform_classes" struct="jvmtiCapabilities"/>
7431 capability).
7432 If a class is not modifiable (<paramlink id="is_modifiable_class_ptr"/>
7433 returns <code>JNI_FALSE</code>) the class can be neither
7434 redefined nor retransformed.
7435 <p/>
7436 Primitive classes (for example, <code>java.lang.Integer.TYPE</code>),
7437 array classes, and some implementation defined classes are never modifiable.
7438 <p/>
7439 </description>
7440 <origin>new</origin>
7441 <capabilities>
7442 <capability id="can_redefine_any_class">
7443 If possessed then all classes (except primitive, array, and some implementation defined
7444 classes) are modifiable (redefine or retransform).
7445 </capability>
7446 <capability id="can_retransform_any_class">
7447 If possessed then all classes (except primitive, array, and some implementation defined
7448 classes) are modifiable with <functionlink id="RetransformClasses"/>.
7449 </capability>
7450 <capability id="can_redefine_classes">
7451 No effect on the result of the function.
7452 But must additionally be possessed to modify the class with
7453 <functionlink id="RedefineClasses"/>.
7454 </capability>
7455 <capability id="can_retransform_classes">
7456 No effect on the result of the function.
7457 But must additionally be possessed to modify the class with
7458 <functionlink id="RetransformClasses"/>.
7459 </capability>
7460 </capabilities>
7461 <parameters>
7462 <param id="klass">
7463 <jclass/>
7464 <description>
7465 The class to query.
7466 </description>
7467 </param>
7468 <param id="is_modifiable_class_ptr">
7469 <outptr><jboolean/></outptr>
7470 <description>
7471 On return, points to the boolean result of this function.
7472 </description>
7473 </param>
7474 </parameters>
7475 <errors>
7476 </errors>
7477 </function>
7478
7479 <function id="GetClassLoader" phase="start" num="57">
7480 <synopsis>Get Class Loader</synopsis>
7481 <description>
7482 For the class indicated by <code>klass</code>, return via
7483 <code>classloader_ptr</code> a reference to the class loader for the
7484 class.
7485 </description>
7486 <origin>jvmdi</origin>
7487 <capabilities>
7488 </capabilities>
7489 <parameters>
7490 <param id="klass">
7491 <jclass/>
7492 <description>
7493 The class to query.
7494 </description>
7495 </param>
7496 <param id="classloader_ptr">
7497 <outptr><jobject/></outptr>
7498 <description>
7499 On return, points to the class loader that loaded
7500 this class.
7501 If the class was not created by a class loader
7502 or if the class loader is the bootstrap class loader,
7503 points to <code>NULL</code>.
7504 </description>
7505 </param>
7506 </parameters>
7507 <errors>
7508 </errors>
7509
7510 </function>
7511
7512 <function id="GetSourceDebugExtension" phase="start" num="90">
7513 <synopsis>Get Source Debug Extension</synopsis>
7514 <description>
7515 For the class indicated by <code>klass</code>, return the debug
7516 extension via <code>source_debug_extension_ptr</code>.
7517 The returned string
7518 contains exactly the debug extension information present in the
7519 class file of <code>klass</code>.
7520 </description>
7521 <origin>jvmdi</origin>
7522 <capabilities>
7523 <required id="can_get_source_debug_extension"></required>
7524 </capabilities>
7525 <parameters>
7526 <param id="klass">
7527 <jclass/>
7528 <description>
7529 The class to query.
7530 </description>
7531 </param>
7532 <param id="source_debug_extension_ptr">
7533 <allocbuf><char/></allocbuf>
7534 <description>
7535 On return, points to the class's debug extension, encoded as a
7536 <internallink id="mUTF">modified UTF-8</internallink> string.
7537 </description>
7538 </param>
7539 </parameters>
7540 <errors>
7541 <error id="JVMTI_ERROR_ABSENT_INFORMATION">
7542 Class information does not include a debug extension.
7543 </error>
7544 </errors>
7545 </function>
7546
7547 <function id="RetransformClasses" jkernel="yes" num="152" since="1.1">
7548 <synopsis>Retransform Classes</synopsis>
7549 <description>
7550 This function facilitates the
7551 <internallink id="bci">bytecode instrumentation</internallink>
7552 of already loaded classes.
7553 To replace the class definition without reference to the existing
7554 bytecodes, as one might do when recompiling from source for
7555 fix-and-continue debugging, <functionlink id="RedefineClasses"/>
7556 function should be used instead.
7557 <p/>
7558 When classes are initially loaded or when they are
7559 <functionlink id="RedefineClasses">redefined</functionlink>,
7560 the initial class file bytes can be transformed with the
7561 <eventlink id="ClassFileLoadHook"/> event.
7562 This function reruns the transformation process
7563 (whether or not a transformation has previously occurred).
7564 This retransformation follows these steps:
7565 <ul>
7566 <li>starting from the initial class file bytes
7567 </li>
7568 <li>for each <fieldlink id="can_retransform_classes"
7569 struct="jvmtiCapabilities">retransformation
7570 incapable</fieldlink>
7571 agent which received a
7572 <code>ClassFileLoadHook</code> event during the previous
7573 load or redefine, the bytes it returned
7574 (via the <code>new_class_data</code> parameter)
7575 are reused as the output of the transformation;
7576 note that this is equivalent to reapplying
7577 the previous transformation, unaltered. except that
7578 the <code>ClassFileLoadHook</code> event
7579 is <b>not</b> sent to these agents
7580 </li>
7581 <li>for each <fieldlink id="can_retransform_classes"
7582 struct="jvmtiCapabilities">retransformation
7583 capable</fieldlink>
7584 agent, the <code>ClassFileLoadHook</code> event is sent,
7585 allowing a new transformation to be applied
7586 </li>
7587 <li>the transformed class file bytes are installed as the new
7588 definition of the class
7589 </li>
7590 </ul>
7591 See the <eventlink id="ClassFileLoadHook"/> event for more details.
7592 <p/>
7593 The initial class file bytes represent the bytes passed to
7594 <code>ClassLoader.defineClass</code>
7595 or <code>RedefineClasses</code> (before any transformations
7596 were applied), however they may not exactly match them.
7597 The constant pool may differ in ways described in
7598 <functionlink id="GetConstantPool"/>.
7599 Constant pool indices in the bytecodes of methods will correspond.
7600 Some attributes may not be present.
7601 Where order is not meaningful, for example the order of methods,
7602 order may not be preserved.
7603 <p/>
7604 Retransformation can cause new versions of methods to be installed.
7605 Old method versions may become
7606 <internallink id="obsoleteMethods">obsolete</internallink>
7607 The new method version will be used on new invokes.
7608 If a method has active stack frames, those active frames continue to
7609 run the bytecodes of the original method version.
7610 <p/>
7611 This function does not cause any initialization except that which
7612 would occur under the customary JVM semantics.
7613 In other words, retransforming a class does not cause its initializers to be
7614 run. The values of static fields will remain as they were
7615 prior to the call.
7616 <p/>
7617 Threads need not be suspended.
7618 <p/>
7619 All breakpoints in the class are cleared.
7620 <p/>
7621 All attributes are updated.
7622 <p/>
7623 Instances of the retransformed class are not affected -- fields retain their
7624 previous values.
7625 <functionlink id="GetTag">Tags</functionlink> on the instances are
7626 also unaffected.
7627 <p/>
7628 In response to this call, no events other than the
7629 <eventlink id="ClassFileLoadHook"/> event
7630 will be sent.
7631 <p/>
7632 The retransformation may change method bodies, the constant pool and attributes.
7633 The retransformation must not add, remove or rename fields or methods, change the
7634 signatures of methods, change modifiers, or change inheritance.
7635 These restrictions may be lifted in future versions.
7636 See the error return description below for information on error codes
7637 returned if an unsupported retransformation is attempted.
7638 The class file bytes are not verified or installed until they have passed
7639 through the chain of <eventlink id="ClassFileLoadHook"/> events, thus the
7640 returned error code reflects the result of the transformations.
7641 If any error code is returned other than <code>JVMTI_ERROR_NONE</code>,
7642 none of the classes to be retransformed will have a new definition installed.
7643 When this function returns (with the error code of <code>JVMTI_ERROR_NONE</code>)
7644 all of the classes to be retransformed will have their new definitions installed.
7645 </description>
7646 <origin>new</origin>
7647 <capabilities>
7648 <required id="can_retransform_classes"></required>
7649 <capability id="can_retransform_any_class"></capability>
7650 </capabilities>
7651 <parameters>
7652 <param id="class_count">
7653 <jint min="0"/>
7654 <description>
7655 The number of classes to be retransformed.
7656 </description>
7657 </param>
7658 <param id="classes">
7659 <inbuf incount="class_count"><jclass/></inbuf>
7660 <description>
7661 The array of classes to be retransformed.
7662 </description>
7663 </param>
7664 </parameters>
7665 <errors>
7666 <error id="JVMTI_ERROR_UNMODIFIABLE_CLASS">
7667 One of the <paramlink id="classes"/> cannot be modified.
7668 See <functionlink id="IsModifiableClass"/>.
7669 </error>
7670 <error id="JVMTI_ERROR_INVALID_CLASS">
7671 One of the <paramlink id="classes"/> is not a valid class.
7672 </error>
7673 <error id="JVMTI_ERROR_UNSUPPORTED_VERSION">
7674 A retransformed class file has a version number not supported by this VM.
7675 </error>
7676 <error id="JVMTI_ERROR_INVALID_CLASS_FORMAT">
7677 A retransformed class file is malformed (The VM would return a <code>ClassFormatError</code>).
7678 </error>
7679 <error id="JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION">
7680 The retransformed class file definitions would lead to a circular definition
7681 (the VM would return a <code>ClassCircularityError</code>).
7682 </error>
7683 <error id="JVMTI_ERROR_FAILS_VERIFICATION">
7684 The retransformed class file bytes fail verification.
7685 </error>
7686 <error id="JVMTI_ERROR_NAMES_DONT_MATCH">
7687 The class name defined in a retransformed class file is
7688 different from the name in the old class object.
7689 </error>
7690 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED">
7691 A retransformed class file would require adding a method.
7692 </error>
7693 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED">
7694 A retransformed class file changes a field.
7695 </error>
7696 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED">
7697 A direct superclass is different for a retransformed class file,
7698 or the set of directly implemented
7699 interfaces is different.
7700 </error>
7701 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED">
7702 A retransformed class file does not declare a method
7703 declared in the old class version.
7704 </error>
7705 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED">
7706 A retransformed class file has different class modifiers.
7707 </error>
7708 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED">
7709 A method in the retransformed class file has different modifiers
7710 than its counterpart in the old class version.
7711 </error>
7712 </errors>
7713 </function>
7714
7715 <function id="RedefineClasses" jkernel="yes" num="87">
7716 <synopsis>Redefine Classes</synopsis>
7717 <typedef id="jvmtiClassDefinition" label="Class redefinition description">
7718 <field id="klass">
7719 <jclass/>
7720 <description>
7721 Class object for this class
7722 </description>
7723 </field>
7724 <field id="class_byte_count">
7725 <jint/>
7726 <description>
7727 Number of bytes defining class (below)
7728 </description>
7729 </field>
7730 <field id="class_bytes">
7731 <inbuf incount="class_byte_count"><uchar/></inbuf>
7732 <description>
7733 Bytes defining class (in <vmspec chapter="4"/>)
7734 </description>
7735 </field>
7736 </typedef>
7737 <description>
7738 All classes given are redefined according to the definitions
7739 supplied.
7740 This function is used to replace the definition of a class
7741 with a new definition, as might be needed in fix-and-continue
7742 debugging.
7743 Where the existing class file bytes are to be transformed, for
7744 example in
7745 <internallink id="bci">bytecode instrumentation</internallink>,
7746 <functionlink id="RetransformClasses"/> should be used.
7747 <p/>
7748 Redefinition can cause new versions of methods to be installed.
7749 Old method versions may become
7750 <internallink id="obsoleteMethods">obsolete</internallink>
7751 The new method version will be used on new invokes.
7752 If a method has active stack frames, those active frames continue to
7753 run the bytecodes of the original method version.
7754 If resetting of stack frames is desired, use
7755 <functionlink id="PopFrame"></functionlink>
7756 to pop frames with obsolete method versions.
7757 <p/>
7758 This function does not cause any initialization except that which
7759 would occur under the customary JVM semantics.
7760 In other words, redefining a class does not cause its initializers to be
7761 run. The values of static fields will remain as they were
7762 prior to the call.
7763 <p/>
7764 Threads need not be suspended.
7765 <p/>
7766 All breakpoints in the class are cleared.
7767 <p/>
7768 All attributes are updated.
7769 <p/>
7770 Instances of the redefined class are not affected -- fields retain their
7771 previous values.
7772 <functionlink id="GetTag">Tags</functionlink> on the instances are
7773 also unaffected.
7774 <p/>
7775 In response to this call, the <jvmti/> event
7776 <eventlink id="ClassFileLoadHook">Class File Load Hook</eventlink>
7777 will be sent (if enabled), but no other <jvmti/> events will be sent.
7778 <p/>
7779 The redefinition may change method bodies, the constant pool and attributes.
7780 The redefinition must not add, remove or rename fields or methods, change the
7781 signatures of methods, change modifiers, or change inheritance.
7782 These restrictions may be lifted in future versions.
7783 See the error return description below for information on error codes
7784 returned if an unsupported redefinition is attempted.
7785 The class file bytes are not verified or installed until they have passed
7786 through the chain of <eventlink id="ClassFileLoadHook"/> events, thus the
7787 returned error code reflects the result of the transformations applied
7788 to the bytes passed into <paramlink id="class_definitions"/>.
7789 If any error code is returned other than <code>JVMTI_ERROR_NONE</code>,
7790 none of the classes to be redefined will have a new definition installed.
7791 When this function returns (with the error code of <code>JVMTI_ERROR_NONE</code>)
7792 all of the classes to be redefined will have their new definitions installed.
7793 </description>
7794 <origin>jvmdi</origin>
7795 <capabilities>
7796 <required id="can_redefine_classes"></required>
7797 <capability id="can_redefine_any_class"></capability>
7798 </capabilities>
7799 <parameters>
7800 <param id="class_count">
7801 <jint min="0"/>
7802 <description>
7803 The number of classes specified in <code>class_definitions</code>
7804 </description>
7805 </param>
7806 <param id="class_definitions">
7807 <inbuf incount="class_count"><struct>jvmtiClassDefinition</struct></inbuf>
7808 <description>
7809 The array of new class definitions
7810 </description>
7811 </param>
7812 </parameters>
7813 <errors>
7814 <error id="JVMTI_ERROR_NULL_POINTER">
7815 One of <code>class_bytes</code> is <code>NULL</code>.
7816 </error>
7817 <error id="JVMTI_ERROR_UNMODIFIABLE_CLASS">
7818 An element of <code>class_definitions</code> cannot be modified.
7819 See <functionlink id="IsModifiableClass"/>.
7820 </error>
7821 <error id="JVMTI_ERROR_INVALID_CLASS">
7822 An element of <code>class_definitions</code> is not a valid class.
7823 </error>
7824 <error id="JVMTI_ERROR_UNSUPPORTED_VERSION">
7825 A new class file has a version number not supported by this VM.
7826 </error>
7827 <error id="JVMTI_ERROR_INVALID_CLASS_FORMAT">
7828 A new class file is malformed (The VM would return a <code>ClassFormatError</code>).
7829 </error>
7830 <error id="JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION">
7831 The new class file definitions would lead to a circular definition
7832 (the VM would return a <code>ClassCircularityError</code>).
7833 </error>
7834 <error id="JVMTI_ERROR_FAILS_VERIFICATION">
7835 The class bytes fail verification.
7836 </error>
7837 <error id="JVMTI_ERROR_NAMES_DONT_MATCH">
7838 The class name defined in a new class file is
7839 different from the name in the old class object.
7840 </error>
7841 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED">
7842 A new class file would require adding a method.
7843 </error>
7844 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED">
7845 A new class version changes a field.
7846 </error>
7847 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED">
7848 A direct superclass is different for a new class
7849 version, or the set of directly implemented
7850 interfaces is different.
7851 </error>
7852 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED">
7853 A new class version does not declare a method
7854 declared in the old class version.
7855 </error>
7856 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED">
7857 A new class version has different modifiers.
7858 </error>
7859 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED">
7860 A method in the new class version has different modifiers
7861 than its counterpart in the old class version.
7862 </error>
7863 <error id="JVMTI_ERROR_UNMODIFIABLE_MODULE">
7864 A module cannot be modified.
7865 See <functionlink id="IsModifiableModule"/>.
7866 </error>
7867 </errors>
7868 </function>
7869
7870 </category>
7871
7872 <category id="object" label="Object">
7873
7874 <function id="GetObjectSize" jkernel="yes" phase="start" num="154">
7875 <synopsis>Get Object Size</synopsis>
7876 <description>
7877 For the object indicated by <code>object</code>,
7878 return via <code>size_ptr</code> the size of the object.
7879 This size is an implementation-specific approximation of
7880 the amount of storage consumed by this object.
7881 It may include some or all of the object's overhead, and thus
7882 is useful for comparison within an implementation but not
7883 between implementations.
7884 The estimate may change during a single invocation of the JVM.
7885 </description>
7886 <origin>new</origin>
7887 <capabilities>
7888 </capabilities>
7889 <parameters>
7890 <param id="object">
7891 <jobject/>
7892 <description>
7893 The object to query.
7894 </description>
7895 </param>
7896 <param id="size_ptr">
7897 <outptr><jlong/></outptr>
7898 <description>
7899 On return, points to the object's size in bytes.
7900 </description>
7901 </param>
7902 </parameters>
7903 <errors>
7904 </errors>
7905 </function>
7906
7907 <function id="GetObjectHashCode" phase="start" num="58">
7908 <synopsis>Get Object Hash Code</synopsis>
7909 <description>
7910 For the object indicated by <code>object</code>,
7911 return via <code>hash_code_ptr</code> a hash code.
7912 This hash code could be used to maintain a hash table of object references,
7913 however, on some implementations this can cause significant performance
7914 impacts--in most cases
7915 <internallink id="Heap">tags</internallink>
7916 will be a more efficient means of associating information with objects.
7917 This function guarantees
7918 the same hash code value for a particular object throughout its life
7919 </description>
7920 <origin>jvmdi</origin>
7921 <capabilities>
7922 </capabilities>
7923 <parameters>
7924 <param id="object">
7925 <jobject/>
7926 <description>
7927 The object to query.
7928 </description>
7929 </param>
7930 <param id="hash_code_ptr">
7931 <outptr><jint/></outptr>
7932 <description>
7933 On return, points to the object's hash code.
7934 </description>
7935 </param>
7936 </parameters>
7937 <errors>
7938 </errors>
7939 </function>
7940
7941 <function id="GetObjectMonitorUsage" num="59">
7942 <synopsis>Get Object Monitor Usage</synopsis>
7943 <typedef id="jvmtiMonitorUsage" label="Object monitor usage information">
7944 <field id="owner">
7945 <jthread/>
7946 <description>
7947 The thread owning this monitor, or <code>NULL</code> if unused
7948 </description>
7949 </field>
7950 <field id="entry_count">
7951 <jint/>
7952 <description>
7953 The number of times the owning thread has entered the monitor
7954 </description>
7955 </field>
7956 <field id="waiter_count">
7957 <jint/>
7958 <description>
7959 The number of threads waiting to own this monitor
7960 </description>
7961 </field>
7962 <field id="waiters">
7963 <allocfieldbuf><jthread/></allocfieldbuf>
7964 <description>
7965 The <code>waiter_count</code> waiting threads
7966 </description>
7967 </field>
7968 <field id="notify_waiter_count">
7969 <jint/>
7970 <description>
7971 The number of threads waiting to be notified by this monitor
7972 </description>
7973 </field>
7974 <field id="notify_waiters">
7975 <allocfieldbuf><jthread/></allocfieldbuf>
7976 <description>
7977 The <code>notify_waiter_count</code> threads waiting to be notified
7978 </description>
7979 </field>
7980 </typedef>
7981 <description>
7982 Get information about the object's monitor.
7983 The fields of the <functionlink id="jvmtiMonitorUsage"></functionlink> structure
7984 are filled in with information about usage of the monitor.
7985 <todo>
7986 Decide and then clarify suspend requirements.
7987 </todo>
7988 </description>
7989 <origin>jvmdi</origin>
7990 <capabilities>
7991 <required id="can_get_monitor_info"></required>
7992 </capabilities>
7993 <parameters>
7994 <param id="object">
7995 <jobject/>
7996 <description>
7997 The object to query.
7998 </description>
7999 </param>
8000 <param id="info_ptr">
8001 <outptr><struct>jvmtiMonitorUsage</struct></outptr>
8002 <description>
8003 On return, filled with monitor information for the
8004 specified object.
8005 </description>
8006 </param>
8007 </parameters>
8008 <errors>
8009 </errors>
8010 </function>
8011
8012 <elide>
8013 <function id="GetObjectMonitors" num="116">
8014 <synopsis>Get Object Monitors</synopsis>
8015 <description>
8016 Return the list of object monitors.
8017 <p/>
8018 Note: details about each monitor can be examined with
8019 <functionlink id="GetObjectMonitorUsage"></functionlink>.
8020 </description>
8021 <origin>new</origin>
8022 <capabilities>
8023 <required id="can_get_monitor_info"></required>
8024 </capabilities>
8025 <parameters>
8026 <param id="monitorCnt">
8027 <outptr><jint/></outptr>
8028 <description>
8029 On return, pointer to the number
8030 of monitors returned in <code>monitors_ptr</code>.
8031 </description>
8032 </param>
8033 <param id="monitors_ptr">
8034 <allocbuf outcount="monitorCnt"><jobject/></allocbuf>
8035 <description>
8036 On return, pointer to the monitor list.
8037 </description>
8038 </param>
8039 </parameters>
8040 <errors>
8041 </errors>
8042 </function>
8043 </elide>
8044
8045 </category>
8046
8047 <category id="fieldCategory" label="Field">
8048
8049 <intro>
8050 </intro>
8051
8052 <function id="GetFieldName" phase="start" num="60">
8053 <synopsis>Get Field Name (and Signature)</synopsis>
8054 <description>
8055 For the field indicated by <paramlink id="klass"/> and <paramlink id="field"/>,
8056 return the field name via <paramlink id="name_ptr"/> and field signature via
8057 <paramlink id="signature_ptr"/>.
8058 <p/>
8059 Field signatures are defined in the
8060 <externallink id="jni/index.html">JNI Specification</externallink>
8061 and are referred to as <code>field descriptors</code> in
8062 <vmspec chapter="4.3.2"/>.
8063 </description>
8064 <origin>jvmdiClone</origin>
8065 <capabilities>
8066 </capabilities>
8067 <parameters>
8068 <param id="klass">
8069 <jclass field="field"/>
8070 <description>
8071 The class of the field to query.
8072 </description>
8073 </param>
8074 <param id="field">
8075 <jfieldID class="klass"/>
8076 <description>
8077 The field to query.
8078 </description>
8079 </param>
8080 <param id="name_ptr">
8081 <allocbuf>
8082 <char/>
8083 <nullok>the name is not returned</nullok>
8084 </allocbuf>
8085 <description>
8086 On return, points to the field name, encoded as a
8087 <internallink id="mUTF">modified UTF-8</internallink> string.
8088 </description>
8089 </param>
8090 <param id="signature_ptr">
8091 <allocbuf>
8092 <char/>
8093 <nullok>the signature is not returned</nullok>
8094 </allocbuf>
8095 <description>
8096 On return, points to the field signature, encoded as a
8097 <internallink id="mUTF">modified UTF-8</internallink> string.
8098 </description>
8099 </param>
8100 <param id="generic_ptr">
8101 <allocbuf>
8102 <char/>
8103 <nullok>the generic signature is not returned</nullok>
8104 </allocbuf>
8105 <description>
8106 On return, points to the generic signature of the field, encoded as a
8107 <internallink id="mUTF">modified UTF-8</internallink> string.
8108 If there is no generic signature attribute for the field, then,
8109 on return, points to <code>NULL</code>.
8110 </description>
8111 </param>
8112 </parameters>
8113 <errors>
8114 </errors>
8115 </function>
8116
8117 <function id="GetFieldDeclaringClass" phase="start" num="61">
8118 <synopsis>Get Field Declaring Class</synopsis>
8119 <description>
8120 For the field indicated by <code>klass</code> and <code>field</code>
8121 return the class that defined it via <code>declaring_class_ptr</code>.
8122 The declaring class will either be <code>klass</code>, a superclass, or
8123 an implemented interface.
8124 </description>
8125 <origin>jvmdi</origin>
8126 <capabilities>
8127 </capabilities>
8128 <parameters>
8129 <param id="klass">
8130 <jclass field="field"/>
8131 <description>
8132 The class to query.
8133 </description>
8134 </param>
8135 <param id="field">
8136 <jfieldID class="klass"/>
8137 <description>
8138 The field to query.
8139 </description>
8140 </param>
8141 <param id="declaring_class_ptr">
8142 <outptr><jclass/></outptr>
8143 <description>
8144 On return, points to the declaring class
8145 </description>
8146 </param>
8147 </parameters>
8148 <errors>
8149 </errors>
8150 </function>
8151
8152 <function id="GetFieldModifiers" phase="start" num="62">
8153 <synopsis>Get Field Modifiers</synopsis>
8154 <description>
8155 For the field indicated by <code>klass</code> and <code>field</code>
8156 return the access flags via <code>modifiers_ptr</code>.
8157 Access flags are defined in <vmspec chapter="4"/>.
8158 </description>
8159 <origin>jvmdi</origin>
8160 <capabilities>
8161 </capabilities>
8162 <parameters>
8163 <param id="klass">
8164 <jclass field="field"/>
8165 <description>
8166 The class to query.
8167 </description>
8168 </param>
8169 <param id="field">
8170 <jfieldID class="klass"/>
8171 <description>
8172 The field to query.
8173 </description>
8174 </param>
8175 <param id="modifiers_ptr">
8176 <outptr><jint/></outptr>
8177 <description>
8178 On return, points to the access flags.
8179 </description>
8180 </param>
8181 </parameters>
8182 <errors>
8183 </errors>
8184 </function>
8185
8186 <function id="IsFieldSynthetic" phase="start" num="63">
8187 <synopsis>Is Field Synthetic</synopsis>
8188 <description>
8189 For the field indicated by <code>klass</code> and <code>field</code>, return a
8190 value indicating whether the field is synthetic via <code>is_synthetic_ptr</code>.
8191 Synthetic fields are generated by the compiler but not present in the
8192 original source code.
8193 </description>
8194 <origin>jvmdi</origin>
8195 <capabilities>
8196 <required id="can_get_synthetic_attribute"></required>
8197 </capabilities>
8198 <parameters>
8199 <param id="klass">
8200 <jclass field="field"/>
8201 <description>
8202 The class of the field to query.
8203 </description>
8204 </param>
8205 <param id="field">
8206 <jfieldID class="klass"/>
8207 <description>
8208 The field to query.
8209 </description>
8210 </param>
8211 <param id="is_synthetic_ptr">
8212 <outptr><jboolean/></outptr>
8213 <description>
8214 On return, points to the boolean result of this function.
8215 </description>
8216 </param>
8217 </parameters>
8218 <errors>
8219 </errors>
8220 </function>
8221
8222 </category>
8223
8224 <category id="method" label="Method">
8225
8226 <intro>
8227 These functions provide information about a method (represented as a
8228 <typelink id="jmethodID"/>) and set how methods are processed.
8229 </intro>
8230
8231 <intro id="obsoleteMethods" label="Obsolete Methods">
8232 The functions <functionlink id="RetransformClasses"/> and
8233 <functionlink id="RedefineClasses"/> can cause new versions
8234 of methods to be installed.
8235 An original version of a method is considered equivalent
8236 to the new version if:
8237 <ul>
8238 <li>their bytecodes are the same except for indices into the
8239 constant pool and </li>
8240 <li>the referenced constants are equal.</li>
8241 </ul>
8242 An original method version which is not equivalent to the
8243 new method version is called obsolete and is assigned a new method ID;
8244 the original method ID now refers to the new method version.
8245 A method ID can be tested for obsolescence with
8246 <functionlink id="IsMethodObsolete"/>.
8247 </intro>
8248
8249 <function id="GetMethodName" phase="start" num="64">
8250 <synopsis>Get Method Name (and Signature)</synopsis>
8251 <description>
8252 For the method indicated by <code>method</code>,
8253 return the method name via <code>name_ptr</code> and method signature via
8254 <code>signature_ptr</code>.
8255 <p/>
8256 Method signatures are defined in the
8257 <externallink id="jni/index.html">JNI Specification</externallink>
8258 and are referred to as <code>method descriptors</code> in
8259 <vmspec chapter="4.3.3"/>.
8260 Note this is different
8261 than method signatures as defined in the <i>Java Language Specification</i>.
8262 </description>
8263 <origin>jvmdiClone</origin>
8264 <capabilities>
8265 </capabilities>
8266 <parameters>
8267 <param id="method">
8268 <jmethodID/>
8269 <description>
8270 The method to query.
8271 </description>
8272 </param>
8273 <param id="name_ptr">
8274 <allocbuf>
8275 <char/>
8276 <nullok>the name is not returned</nullok>
8277 </allocbuf>
8278 <description>
8279 On return, points to the method name, encoded as a
8280 <internallink id="mUTF">modified UTF-8</internallink> string.
8281 </description>
8282 </param>
8283 <param id="signature_ptr">
8284 <allocbuf>
8285 <char/>
8286 <nullok>the signature is not returned</nullok>
8287 </allocbuf>
8288 <description>
8289 On return, points to the method signature, encoded as a
8290 <internallink id="mUTF">modified UTF-8</internallink> string.
8291 </description>
8292 </param>
8293 <param id="generic_ptr">
8294 <allocbuf>
8295 <char/>
8296 <nullok>the generic signature is not returned</nullok>
8297 </allocbuf>
8298 <description>
8299 On return, points to the generic signature of the method, encoded as a
8300 <internallink id="mUTF">modified UTF-8</internallink> string.
8301 If there is no generic signature attribute for the method, then,
8302 on return, points to <code>NULL</code>.
8303 </description>
8304 </param>
8305 </parameters>
8306 <errors>
8307 </errors>
8308 </function>
8309
8310 <function id="GetMethodDeclaringClass" phase="start" num="65">
8311 <synopsis>Get Method Declaring Class</synopsis>
8312 <description>
8313 For the method indicated by <code>method</code>,
8314 return the class that defined it via <code>declaring_class_ptr</code>.
8315 </description>
8316 <origin>jvmdi</origin>
8317 <capabilities>
8318 </capabilities>
8319 <parameters>
8320 <param id="klass">
8321 <jclass method="method"/>
8322 <description>
8323 The class to query.
8324 </description>
8325 </param>
8326 <param id="method">
8327 <jmethodID class="klass"/>
8328 <description>
8329 The method to query.
8330 </description>
8331 </param>
8332 <param id="declaring_class_ptr">
8333 <outptr><jclass/></outptr>
8334 <description>
8335 On return, points to the declaring class
8336 </description>
8337 </param>
8338 </parameters>
8339 <errors>
8340 </errors>
8341 </function>
8342
8343 <function id="GetMethodModifiers" phase="start" num="66">
8344 <synopsis>Get Method Modifiers</synopsis>
8345 <description>
8346 For the method indicated by <code>method</code>,
8347 return the access flags via <code>modifiers_ptr</code>.
8348 Access flags are defined in <vmspec chapter="4"/>.
8349 </description>
8350 <origin>jvmdi</origin>
8351 <capabilities>
8352 </capabilities>
8353 <parameters>
8354 <param id="klass">
8355 <jclass method="method"/>
8356 <description>
8357 The class to query.
8358 </description>
8359 </param>
8360 <param id="method">
8361 <jmethodID class="klass"/>
8362 <description>
8363 The method to query.
8364 </description>
8365 </param>
8366 <param id="modifiers_ptr">
8367 <outptr><jint/></outptr>
8368 <description>
8369 On return, points to the access flags.
8370 </description>
8371 </param>
8372 </parameters>
8373 <errors>
8374 </errors>
8375 </function>
8376
8377 <function id="GetMaxLocals" phase="start" num="68">
8378 <synopsis>Get Max Locals</synopsis>
8379 <description>
8380 For the method indicated by <code>method</code>,
8381 return the number of local variable slots used by the method,
8382 including the local variables used to pass parameters to the
8383 method on its invocation.
8384 <p/>
8385 See <code>max_locals</code> in <vmspec chapter="4.7.3"/>.
8386 </description>
8387 <origin>jvmdi</origin>
8388 <capabilities>
8389 </capabilities>
8390 <parameters>
8391 <param id="klass">
8392 <jclass method="method"/>
8393 <description>
8394 The class to query.
8395 </description>
8396 </param>
8397 <param id="method">
8398 <jmethodID class="klass" native="error"/>
8399 <description>
8400 The method to query.
8401 </description>
8402 </param>
8403 <param id="max_ptr">
8404 <outptr><jint/></outptr>
8405 <description>
8406 On return, points to the maximum number of local slots
8407 </description>
8408 </param>
8409 </parameters>
8410 <errors>
8411 </errors>
8412 </function>
8413
8414 <function id="GetArgumentsSize" phase="start" num="69">
8415 <synopsis>Get Arguments Size</synopsis>
8416 <description>
8417 For the method indicated by <code>method</code>,
8418 return via <code>max_ptr</code> the number of local variable slots used
8419 by the method's arguments.
8420 Note that two-word arguments use two slots.
8421 </description>
8422 <origin>jvmdi</origin>
8423 <capabilities>
8424 </capabilities>
8425 <parameters>
8426 <param id="klass">
8427 <jclass method="method"/>
8428 <description>
8429 The class to query.
8430 </description>
8431 </param>
8432 <param id="method">
8433 <jmethodID class="klass" native="error"/>
8434 <description>
8435 The method to query.
8436 </description>
8437 </param>
8438 <param id="size_ptr">
8439 <outptr><jint/></outptr>
8440 <description>
8441 On return, points to the number of argument slots
8442 </description>
8443 </param>
8444 </parameters>
8445 <errors>
8446 </errors>
8447 </function>
8448
8449 <function id="GetLineNumberTable" phase="start" num="70">
8450 <synopsis>Get Line Number Table</synopsis>
8451 <typedef id="jvmtiLineNumberEntry" label="Line number table entry">
8452 <field id="start_location">
8453 <jlocation/>
8454 <description>
8455 the <datalink id="jlocation"></datalink> where the line begins
8456 </description>
8457 </field>
8458 <field id="line_number">
8459 <jint/>
8460 <description>
8461 the line number
8462 </description>
8463 </field>
8464 </typedef>
8465 <description>
8466 For the method indicated by <code>method</code>,
8467 return a table of source line number entries. The size of the table is
8468 returned via <code>entry_count_ptr</code> and the table itself is
8469 returned via <code>table_ptr</code>.
8470 </description>
8471 <origin>jvmdi</origin>
8472 <capabilities>
8473 <required id="can_get_line_numbers"></required>
8474 </capabilities>
8475 <parameters>
8476 <param id="klass">
8477 <jclass method="method"/>
8478 <description>
8479 The class to query.
8480 </description>
8481 </param>
8482 <param id="method">
8483 <jmethodID class="klass" native="error"/>
8484 <description>
8485 The method to query.
8486 </description>
8487 </param>
8488 <param id="entry_count_ptr">
8489 <outptr><jint/></outptr>
8490 <description>
8491 On return, points to the number of entries in the table
8492 </description>
8493 </param>
8494 <param id="table_ptr">
8495 <allocbuf outcount="entry_count_ptr"><struct>jvmtiLineNumberEntry</struct></allocbuf>
8496 <description>
8497 On return, points to the line number table pointer.
8498 </description>
8499 </param>
8500 </parameters>
8501 <errors>
8502 <error id="JVMTI_ERROR_ABSENT_INFORMATION">
8503 Class information does not include line numbers.
8504 </error>
8505 </errors>
8506 </function>
8507
8508 <function id="GetMethodLocation" phase="start" num="71">
8509 <synopsis>Get Method Location</synopsis>
8510 <description>
8511 For the method indicated by <code>method</code>,
8512 return the beginning and ending addresses through
8513 <code>start_location_ptr</code> and <code>end_location_ptr</code>. In a
8514 conventional byte code indexing scheme,
8515 <code>start_location_ptr</code> will always point to zero
8516 and <code>end_location_ptr</code>
8517 will always point to the byte code count minus one.
8518 </description>
8519 <origin>jvmdi</origin>
8520 <capabilities>
8521 </capabilities>
8522 <parameters>
8523 <param id="klass">
8524 <jclass method="method"/>
8525 <description>
8526 The class to query.
8527 </description>
8528 </param>
8529 <param id="method">
8530 <jmethodID class="klass" native="error"/>
8531 <description>
8532 The method to query.
8533 </description>
8534 </param>
8535 <param id="start_location_ptr">
8536 <outptr><jlocation/></outptr>
8537 <description>
8538 On return, points to the first location, or
8539 <code>-1</code> if location information is not available.
8540 If the information is available and
8541 <functionlink id="GetJLocationFormat"></functionlink>
8542 returns <datalink id="JVMTI_JLOCATION_JVMBCI"></datalink>
8543 then this will always be zero.
8544 </description>
8545 </param>
8546 <param id="end_location_ptr">
8547 <outptr><jlocation/></outptr>
8548 <description>
8549 On return, points to the last location,
8550 or <code>-1</code> if location information is not available.
8551 </description>
8552 </param>
8553 </parameters>
8554 <errors>
8555 <error id="JVMTI_ERROR_ABSENT_INFORMATION">
8556 Class information does not include method sizes.
8557 </error>
8558 </errors>
8559 </function>
8560
8561 <function id="GetLocalVariableTable" num="72">
8562 <synopsis>Get Local Variable Table</synopsis>
8563 <typedef id="jvmtiLocalVariableEntry" label="Local variable table entry">
8564 <field id="start_location">
8565 <jlocation/>
8566 <description>
8567 The code array index where the local variable is first valid
8568 (that is, where it must have a value).
8569 </description>
8570 </field>
8571 <field id="length">
8572 <jint/>
8573 <description>
8574 The length of the valid section for this local variable.
8575 The last code array index where the local variable is valid
8576 is <code>start_location + length</code>.
8577 </description>
8578 </field>
8579 <field id="name">
8580 <allocfieldbuf><char/></allocfieldbuf>
8581 <description>
8582 The local variable name, encoded as a
8583 <internallink id="mUTF">modified UTF-8</internallink> string.
8584 </description>
8585 </field>
8586 <field id="signature">
8587 <allocfieldbuf><char/></allocfieldbuf>
8588 <description>
8589 The local variable's type signature, encoded as a
8590 <internallink id="mUTF">modified UTF-8</internallink> string.
8591 The signature format is the same as that defined in
8592 <vmspec chapter="4.3.2"/>.
8593 </description>
8594 </field>
8595 <field id="generic_signature">
8596 <allocfieldbuf><char/></allocfieldbuf>
8597 <description>
8598 The local variable's generic signature, encoded as a
8599 <internallink id="mUTF">modified UTF-8</internallink> string.
8600 The value of this field will be <code>NULL</code> for any local
8601 variable which does not have a generic type.
8602 </description>
8603 </field>
8604 <field id="slot">
8605 <jint/>
8606 <description>
8607 The local variable's slot. See <internallink id="local">Local Variables</internallink>.
8608 </description>
8609 </field>
8610 </typedef>
8611 <description>
8612 Return local variable information.
8613 </description>
8614 <origin>jvmdiClone</origin>
8615 <capabilities>
8616 <required id="can_access_local_variables"></required>
8617 </capabilities>
8618 <parameters>
8619 <param id="method">
8620 <jmethodID native="error"/>
8621 <description>
8622 The method to query.
8623 </description>
8624 </param>
8625 <param id="entry_count_ptr">
8626 <outptr><jint/></outptr>
8627 <description>
8628 On return, points to the number of entries in the table
8629 </description>
8630 </param>
8631 <param id="table_ptr">
8632 <allocbuf outcount="entry_count_ptr"><struct>jvmtiLocalVariableEntry</struct></allocbuf>
8633 <description>
8634 On return, points to an array of local variable table entries.
8635 </description>
8636 </param>
8637 </parameters>
8638 <errors>
8639 <error id="JVMTI_ERROR_ABSENT_INFORMATION">
8640 Class information does not include local variable
8641 information.
8642 </error>
8643 </errors>
8644 </function>
8645
8646 <function id="GetBytecodes" phase="start" num="75">
8647 <synopsis>Get Bytecodes</synopsis>
8648 <description>
8649 For the method indicated by <code>method</code>,
8650 return the byte codes that implement the method. The number of
8651 bytecodes is returned via <code>bytecode_count_ptr</code>. The byte codes
8652 themselves are returned via <code>bytecodes_ptr</code>.
8653 </description>
8654 <origin>jvmdi</origin>
8655 <capabilities>
8656 <required id="can_get_bytecodes"></required>
8657 </capabilities>
8658 <parameters>
8659 <param id="klass">
8660 <jclass method="method"/>
8661 <description>
8662 The class to query.
8663 </description>
8664 </param>
8665 <param id="method">
8666 <jmethodID class="klass" native="error"/>
8667 <description>
8668 The method to query.
8669 </description>
8670 </param>
8671 <param id="bytecode_count_ptr">
8672 <outptr><jint/></outptr>
8673 <description>
8674 On return, points to the length of the byte code array
8675 </description>
8676 </param>
8677 <param id="bytecodes_ptr">
8678 <allocbuf outcount="bytecode_count_ptr"><uchar/></allocbuf>
8679 <description>
8680 On return, points to the pointer to the byte code array
8681 </description>
8682 </param>
8683 </parameters>
8684 <errors>
8685 </errors>
8686 </function>
8687
8688 <function id="IsMethodNative" phase="start" num="76">
8689 <synopsis>Is Method Native</synopsis>
8690 <description>
8691 For the method indicated by <code>method</code>, return a
8692 value indicating whether the method is native via <code>is_native_ptr</code>
8693 </description>
8694 <origin>jvmdi</origin>
8695 <capabilities>
8696 </capabilities>
8697 <parameters>
8698 <param id="klass">
8699 <jclass method="method"/>
8700 <description>
8701 The class to query.
8702 </description>
8703 </param>
8704 <param id="method">
8705 <jmethodID class="klass"/>
8706 <description>
8707 The method to query.
8708 </description>
8709 </param>
8710 <param id="is_native_ptr">
8711 <outptr><jboolean/></outptr>
8712 <description>
8713 On return, points to the boolean result of this function.
8714 </description>
8715 </param>
8716 </parameters>
8717 <errors>
8718 </errors>
8719 </function>
8720
8721 <function id="IsMethodSynthetic" phase="start" num="77">
8722 <synopsis>Is Method Synthetic</synopsis>
8723 <description>
8724 For the method indicated by <code>method</code>, return a
8725 value indicating whether the method is synthetic via <code>is_synthetic_ptr</code>.
8726 Synthetic methods are generated by the compiler but not present in the
8727 original source code.
8728 </description>
8729 <origin>jvmdi</origin>
8730 <capabilities>
8731 <required id="can_get_synthetic_attribute"></required>
8732 </capabilities>
8733 <parameters>
8734 <param id="klass">
8735 <jclass method="method"/>
8736 <description>
8737 The class to query.
8738 </description>
8739 </param>
8740 <param id="method">
8741 <jmethodID class="klass"/>
8742 <description>
8743 The method to query.
8744 </description>
8745 </param>
8746 <param id="is_synthetic_ptr">
8747 <outptr><jboolean/></outptr>
8748 <description>
8749 On return, points to the boolean result of this function.
8750 </description>
8751 </param>
8752 </parameters>
8753 <errors>
8754 </errors>
8755 </function>
8756
8757 <function id="IsMethodObsolete" phase="start" num="91">
8758 <synopsis>Is Method Obsolete</synopsis>
8759 <description>
8760 Determine if a method ID refers to an
8761 <internallink id="obsoleteMethods">obsolete</internallink>
8762 method version.
8763 </description>
8764 <origin>jvmdi</origin>
8765 <capabilities>
8766 </capabilities>
8767 <parameters>
8768 <param id="klass">
8769 <jclass method="method"/>
8770 <description>
8771 The class to query.
8772 </description>
8773 </param>
8774 <param id="method">
8775 <jmethodID class="klass"/>
8776 <description>
8777 The method ID to query.
8778 </description>
8779 </param>
8780 <param id="is_obsolete_ptr">
8781 <outptr><jboolean/></outptr>
8782 <description>
8783 On return, points to the boolean result of this function.
8784 </description>
8785 </param>
8786 </parameters>
8787 <errors>
8788 </errors>
8789 </function>
8790
8791 <function id="SetNativeMethodPrefix" jkernel="yes" phase="any" num="73" since="1.1">
8792 <synopsis>Set Native Method Prefix</synopsis>
8793 <description>
8794 This function modifies the failure handling of
8795 native method resolution by allowing retry
8796 with a prefix applied to the name.
8797 When used with the
8798 <eventlink id="ClassFileLoadHook">ClassFileLoadHook
8799 event</eventlink>, it enables native methods to be
8800 <internallink id="bci">instrumented</internallink>.
8801 <p/>
8802 Since native methods cannot be directly instrumented
8803 (they have no bytecodes), they must be wrapped with
8804 a non-native method which can be instrumented.
8805 For example, if we had:
8806 <example>
8807 native boolean foo(int x);</example>
8808 <p/>
8809 We could transform the class file (with the
8810 ClassFileLoadHook event) so that this becomes:
8811 <example>
8812 boolean foo(int x) {
8813 <i>... record entry to foo ...</i>
8814 return wrapped_foo(x);
8815 }
8816
8817 native boolean wrapped_foo(int x);</example>
8818 <p/>
8819 Where foo becomes a wrapper for the actual native method
8820 with the appended prefix "wrapped_". Note that
8821 "wrapped_" would be a poor choice of prefix since it
8822 might conceivably form the name of an existing method
8823 thus something like "$$$MyAgentWrapped$$$_" would be
8824 better but would make these examples less readable.
8825 <p/>
8826 The wrapper will allow data to be collected on the native
8827 method call, but now the problem becomes linking up the
8828 wrapped method with the native implementation.
8829 That is, the method <code>wrapped_foo</code> needs to be
8830 resolved to the native implementation of <code>foo</code>,
8831 which might be:
8832 <example>
8833 Java_somePackage_someClass_foo(JNIEnv* env, jint x)</example>
8834 <p/>
8835 This function allows the prefix to be specified and the
8836 proper resolution to occur.
8837 Specifically, when the standard resolution fails, the
8838 resolution is retried taking the prefix into consideration.
8839 There are two ways that resolution occurs, explicit
8840 resolution with the JNI function <code>RegisterNatives</code>
8841 and the normal automatic resolution. For
8842 <code>RegisterNatives</code>, the VM will attempt this
8843 association:
8844 <example>
8845 method(foo) -> nativeImplementation(foo)</example>
8846 <p/>
8847 When this fails, the resolution will be retried with
8848 the specified prefix prepended to the method name,
8849 yielding the correct resolution:
8850 <example>
8851 method(wrapped_foo) -> nativeImplementation(foo)</example>
8852 <p/>
8853 For automatic resolution, the VM will attempt:
8854 <example>
8855 method(wrapped_foo) -> nativeImplementation(wrapped_foo)</example>
8856 <p/>
8857 When this fails, the resolution will be retried with
8858 the specified prefix deleted from the implementation name,
8859 yielding the correct resolution:
8860 <example>
8861 method(wrapped_foo) -> nativeImplementation(foo)</example>
8862 <p/>
8863 Note that since the prefix is only used when standard
8864 resolution fails, native methods can be wrapped selectively.
8865 <p/>
8866 Since each <jvmti/> environment is independent and
8867 can do its own transformation of the bytecodes, more
8868 than one layer of wrappers may be applied. Thus each
8869 environment needs its own prefix. Since transformations
8870 are applied in order, the prefixes, if applied, will
8871 be applied in the same order.
8872 The order of transformation application is described in
8873 the <eventlink id="ClassFileLoadHook"/> event.
8874 Thus if three environments applied
8875 wrappers, <code>foo</code> might become
8876 <code>$env3_$env2_$env1_foo</code>. But if, say,
8877 the second environment did not apply a wrapper to
8878 <code>foo</code> it would be just
8879 <code>$env3_$env1_foo</code>. To be able to
8880 efficiently determine the sequence of prefixes,
8881 an intermediate prefix is only applied if its non-native
8882 wrapper exists. Thus, in the last example, even though
8883 <code>$env1_foo</code> is not a native method, the
8884 <code>$env1_</code> prefix is applied since
8885 <code>$env1_foo</code> exists.
8886 <p/>
8887 Since the prefixes are used at resolution time
8888 and since resolution may be arbitrarily delayed, a
8889 native method prefix must remain set as long as there
8890 are corresponding prefixed native methods.
8891 </description>
8892 <origin>new</origin>
8893 <capabilities>
8894 <required id="can_set_native_method_prefix"></required>
8895 </capabilities>
8896 <parameters>
8897 <param id="prefix">
8898 <inbuf>
8899 <char/>
8900 <nullok>
8901 any existing prefix in this environment is cancelled
8902 </nullok>
8903 </inbuf>
8904 <description>
8905 The prefix to apply, encoded as a
8906 <internallink id="mUTF">modified UTF-8</internallink> string.
8907 </description>
8908 </param>
8909 </parameters>
8910 <errors>
8911 </errors>
8912 </function>
8913
8914 <function id="SetNativeMethodPrefixes" jkernel="yes" phase="any" num="74" since="1.1">
8915 <synopsis>Set Native Method Prefixes</synopsis>
8916 <description>
8917 For a normal agent, <functionlink id="SetNativeMethodPrefix"/>
8918 will provide all needed native method prefixing.
8919 For a meta-agent that performs multiple independent class
8920 file transformations (for example as a proxy for another
8921 layer of agents) this function allows each transformation
8922 to have its own prefix.
8923 The prefixes are applied in the order supplied and are
8924 processed in the same manor as described for the
8925 application of prefixes from multiple <jvmti/> environments
8926 in <functionlink id="SetNativeMethodPrefix"/>.
8927 <p/>
8928 Any previous prefixes are replaced. Thus, calling this
8929 function with a <paramlink id="prefix_count"/> of <code>0</code>
8930 disables prefixing in this environment.
8931 <p/>
8932 <functionlink id="SetNativeMethodPrefix"/> and this function
8933 are the two ways to set the prefixes.
8934 Calling <code>SetNativeMethodPrefix</code> with
8935 a prefix is the same as calling this function with
8936 <paramlink id="prefix_count"/> of <code>1</code>.
8937 Calling <code>SetNativeMethodPrefix</code> with
8938 <code>NULL</code> is the same as calling this function with
8939 <paramlink id="prefix_count"/> of <code>0</code>.
8940 </description>
8941 <origin>new</origin>
8942 <capabilities>
8943 <required id="can_set_native_method_prefix"></required>
8944 </capabilities>
8945 <parameters>
8946 <param id="prefix_count">
8947 <jint min="0"/>
8948 <description>
8949 The number of prefixes to apply.
8950 </description>
8951 </param>
8952 <param id="prefixes">
8953 <agentbuf>
8954 <char/>
8955 </agentbuf>
8956 <description>
8957 The prefixes to apply for this environment, each encoded as a
8958 <internallink id="mUTF">modified UTF-8</internallink> string.
8959 </description>
8960 </param>
8961 </parameters>
8962 <errors>
8963 </errors>
8964 </function>
8965
8966 </category>
8967
8968 <category id="RawMonitors" label="Raw Monitor">
8969
8970 <function id="CreateRawMonitor" phase="onload" callbacksafe="safe" num="31">
8971 <synopsis>Create Raw Monitor</synopsis>
8972 <description>
8973 Create a raw monitor.
8974 </description>
8975 <origin>jvmdi</origin>
8976 <capabilities>
8977 </capabilities>
8978 <parameters>
8979 <param id="name">
8980 <inbuf><char/></inbuf>
8981 <description>
8982 A name to identify the monitor, encoded as a
8983 <internallink id="mUTF">modified UTF-8</internallink> string.
8984 </description>
8985 </param>
8986 <param id="monitor_ptr">
8987 <outptr><jrawMonitorID/></outptr>
8988 <description>
8989 On return, points to the created monitor.
8990 </description>
8991 </param>
8992 </parameters>
8993 <errors>
8994 </errors>
8995 </function>
8996
8997 <function id="DestroyRawMonitor" phase="onload" callbacksafe="safe" num="32">
8998 <synopsis>Destroy Raw Monitor</synopsis>
8999 <description>
9000 Destroy the raw monitor.
9001 If the monitor being destroyed has been entered by this thread, it will be
9002 exited before it is destroyed.
9003 If the monitor being destroyed has been entered by another thread,
9004 an error will be returned and the monitor will not be destroyed.
9005 </description>
9006 <origin>jvmdi</origin>
9007 <capabilities>
9008 </capabilities>
9009 <parameters>
9010 <param id="monitor">
9011 <jrawMonitorID/>
9012 <description>
9013 The monitor
9014 </description>
9015 </param>
9016 </parameters>
9017 <errors>
9018 <error id="JVMTI_ERROR_NOT_MONITOR_OWNER">
9019 Not monitor owner
9020 </error>
9021 </errors>
9022 </function>
9023
9024 <function id="RawMonitorEnter" phase="any" callbacksafe="safe" impl="innative notrace" num="33">
9025 <synopsis>Raw Monitor Enter</synopsis>
9026 <description>
9027 Gain exclusive ownership of a raw monitor.
9028 The same thread may enter a monitor more then once.
9029 The thread must
9030 <functionlink id="RawMonitorExit">exit</functionlink>
9031 the monitor the same number of times as it is entered.
9032 If a monitor is entered during <code>OnLoad</code> (before attached threads exist)
9033 and has not exited when attached threads come into existence, the enter
9034 is considered to have occurred on the main thread.
9035 </description>
9036 <origin>jvmdi</origin>
9037 <capabilities>
9038 </capabilities>
9039 <parameters>
9040 <param id="monitor">
9041 <jrawMonitorID/>
9042 <description>
9043 The monitor
9044 </description>
9045 </param>
9046 </parameters>
9047 <errors>
9048 </errors>
9049 </function>
9050
9051 <function id="RawMonitorExit" phase="any" callbacksafe="safe" impl="innative notrace" num="34">
9052 <synopsis>Raw Monitor Exit</synopsis>
9053 <description>
9054 Release exclusive ownership of a raw monitor.
9055 </description>
9056 <origin>jvmdi</origin>
9057 <capabilities>
9058 </capabilities>
9059 <parameters>
9060 <param id="monitor">
9061 <jrawMonitorID/>
9062 <description>
9063 The monitor
9064 </description>
9065 </param>
9066 </parameters>
9067 <errors>
9068 <error id="JVMTI_ERROR_NOT_MONITOR_OWNER">
9069 Not monitor owner
9070 </error>
9071 </errors>
9072 </function>
9073
9074 <function id="RawMonitorWait" phase="any" callbacksafe="safe" impl="innative notrace" num="35">
9075 <synopsis>Raw Monitor Wait</synopsis>
9076 <description>
9077 Wait for notification of the raw monitor.
9078 <p/>
9079 Causes the current thread to wait until either another thread calls
9080 <functionlink id="RawMonitorNotify"/> or
9081 <functionlink id="RawMonitorNotifyAll"/>
9082 for the specified raw monitor, or the specified
9083 <paramlink id="millis">timeout</paramlink>
9084 has elapsed.
9085 </description>
9086 <origin>jvmdi</origin>
9087 <capabilities>
9088 </capabilities>
9089 <parameters>
9090 <param id="monitor">
9091 <jrawMonitorID/>
9092 <description>
9093 The monitor
9094 </description>
9095 </param>
9096 <param id="millis">
9097 <jlong/>
9098 <description>
9099 The timeout, in milliseconds. If the timeout is
9100 zero, then real time is not taken into consideration
9101 and the thread simply waits until notified.
9102 </description>
9103 </param>
9104 </parameters>
9105 <errors>
9106 <error id="JVMTI_ERROR_NOT_MONITOR_OWNER">
9107 Not monitor owner
9108 </error>
9109 <error id="JVMTI_ERROR_INTERRUPT">
9110 Wait was interrupted, try again
9111 </error>
9112 </errors>
9113 </function>
9114
9115 <function id="RawMonitorNotify" phase="any" callbacksafe="safe" impl="notrace" num="36">
9116 <synopsis>Raw Monitor Notify</synopsis>
9117 <description>
9118 Notify a single thread waiting on the raw monitor.
9119 </description>
9120 <origin>jvmdi</origin>
9121 <capabilities>
9122 </capabilities>
9123 <parameters>
9124 <param id="monitor">
9125 <jrawMonitorID/>
9126 <description>
9127 The monitor
9128 </description>
9129 </param>
9130 </parameters>
9131 <errors>
9132 <error id="JVMTI_ERROR_NOT_MONITOR_OWNER">
9133 Not monitor owner
9134 </error>
9135 </errors>
9136 </function>
9137
9138 <function id="RawMonitorNotifyAll" phase="any" callbacksafe="safe" impl="notrace" num="37">
9139 <synopsis>Raw Monitor Notify All</synopsis>
9140 <description>
9141 Notify all threads waiting on the raw monitor.
9142 </description>
9143 <origin>jvmdi</origin>
9144 <capabilities>
9145 </capabilities>
9146 <parameters>
9147 <param id="monitor">
9148 <jrawMonitorID/>
9149 <description>
9150 The monitor
9151 </description>
9152 </param>
9153 </parameters>
9154 <errors>
9155 <error id="JVMTI_ERROR_NOT_MONITOR_OWNER">
9156 Not monitor owner
9157 </error>
9158 </errors>
9159 </function>
9160
9161 <elide>
9162 <function id="GetRawMonitorUse" num="118">
9163 <synopsis>Get Raw Monitor Use</synopsis>
9164 <description>
9165 The fields of the <functionlink id="jvmtiMonitorUsage"></functionlink> structure
9166 are filled in with information about usage of the raw monitor.
9167 </description>
9168 <origin>new</origin>
9169 <capabilities>
9170 <required id="can_get_raw_monitor_usage"></required>
9171 </capabilities>
9172 <parameters>
9173 <param id="monitor">
9174 <jrawMonitorID/>
9175 <description>
9176 the raw monitor to query.
9177 </description>
9178 </param>
9179 <param id="info_ptr">
9180 <outptr><struct>jvmtiMonitorUsage</struct></outptr>
9181 <description>
9182 On return, filled with monitor information for the
9183 specified raw monitor.
9184 </description>
9185 </param>
9186 </parameters>
9187 <errors>
9188 </errors>
9189 </function>
9190
9191 <function id="GetRawMonitors" num="119">
9192 <synopsis>Get Raw Monitors</synopsis>
9193 <description>
9194 Return the list of raw monitors.
9195 <p/>
9196 Note: details about each monitor can be examined with
9197 <functionlink id="GetRawMonitorUse"></functionlink>.
9198 </description>
9199 <origin>new</origin>
9200 <capabilities>
9201 <required id="can_get_raw_monitor_usage"></required>
9202 </capabilities>
9203 <parameters>
9204 <param id="monitorCnt">
9205 <outptr><jint/></outptr>
9206 <description>
9207 On return, pointer to the number
9208 of monitors returned in <code>monitors_ptr</code>.
9209 </description>
9210 </param>
9211 <param id="monitors_ptr">
9212 <allocbuf outcount="monitorCnt"><jrawMonitorID/></allocbuf>
9213 <description>
9214 On return, pointer to the monitor list.
9215 </description>
9216 </param>
9217 </parameters>
9218 <errors>
9219 </errors>
9220 </function>
9221 </elide>
9222 </category>
9223
9224 <category id="jniIntercept" label="JNI Function Interception">
9225
9226 <intro>
9227 Provides the ability to intercept and resend
9228 Java Native Interface (JNI) function calls
9229 by manipulating the JNI function table.
9230 See <externallink id="jni/functions.html">JNI
9231 Functions</externallink> in the <i>Java Native Interface Specification</i>.
9232 <p/>
9233 The following example illustrates intercepting the
9234 <code>NewGlobalRef</code> JNI call in order to count reference
9235 creation.
9236 <example>
9237 JNIEnv original_jni_Functions;
9238 JNIEnv redirected_jni_Functions;
9239 int my_global_ref_count = 0;
9240
9241 jobject
9242 MyNewGlobalRef(JNIEnv *jni_env, jobject lobj) {
9243 ++my_global_ref_count;
9244 return originalJNIFunctions->NewGlobalRef(env, lobj);
9245 }
9246
9247 void
9248 myInit() {
9249 jvmtiError err;
9250
9251 err = (*jvmti_env)->GetJNIFunctionTable(jvmti_env, &original_jni_Functions);
9252 if (err != JVMTI_ERROR_NONE) {
9253 die();
9254 }
9255 err = (*jvmti_env)->GetJNIFunctionTable(jvmti_env, &redirected_jni_Functions);
9256 if (err != JVMTI_ERROR_NONE) {
9257 die();
9258 }
9259 redirectedJNIFunctions->NewGlobalRef = MyNewGlobalRef;
9260 err = (*jvmti_env)->SetJNIFunctionTable(jvmti_env, redirected_jni_Functions);
9261 if (err != JVMTI_ERROR_NONE) {
9262 die();
9263 }
9264 }
9265 </example>
9266 Sometime after <code>myInit</code> is called the user's JNI
9267 code is executed which makes the call to create a new global
9268 reference. Instead of going to the normal JNI implementation
9269 the call goes to <code>myNewGlobalRef</code>. Note that a
9270 copy of the original function table is kept so that the normal
9271 JNI function can be called after the data is collected.
9272 Note also that any JNI functions which are not overwritten
9273 will behave normally.
9274 <todo>
9275 check that the example compiles and executes.
9276 </todo>
9277 </intro>
9278
9279 <function id="SetJNIFunctionTable" phase="start" num="120">
9280 <synopsis>Set JNI Function Table</synopsis>
9281 <description>
9282 Set the JNI function table
9283 in all current and future JNI environments.
9284 As a result, all future JNI calls are directed to the specified functions.
9285 Use <functionlink id="GetJNIFunctionTable"></functionlink> to get the
9286 function table to pass to this function.
9287 For this function to take effect the the updated table entries must be
9288 used by the JNI clients.
9289 Since the table is defined <code>const</code> some compilers may optimize
9290 away the access to the table, thus preventing this function from taking
9291 effect.
9292 The table is copied--changes to the local copy of the
9293 table have no effect.
9294 This function affects only the function table, all other aspects of the environment are
9295 unaffected.
9296 See the examples <internallink id="jniIntercept">above</internallink>.
9297 </description>
9298 <origin>new</origin>
9299 <capabilities>
9300 </capabilities>
9301 <parameters>
9302 <param id="function_table">
9303 <inptr>
9304 <struct>jniNativeInterface</struct>
9305 </inptr>
9306 <description>
9307 Points to the new JNI function table.
9308 </description>
9309 </param>
9310 </parameters>
9311 <errors>
9312 </errors>
9313 </function>
9314
9315 <function id="GetJNIFunctionTable" phase="start" num="121">
9316 <synopsis>Get JNI Function Table</synopsis>
9317 <description>
9318 Get the JNI function table.
9319 The JNI function table is copied into allocated memory.
9320 If <functionlink id="SetJNIFunctionTable"></functionlink>
9321 has been called, the modified (not the original) function
9322 table is returned.
9323 Only the function table is copied, no other aspects of the environment
9324 are copied.
9325 See the examples <internallink id="jniIntercept">above</internallink>.
9326 </description>
9327 <origin>new</origin>
9328 <capabilities>
9329 </capabilities>
9330 <parameters>
9331 <param id="function_table">
9332 <allocbuf>
9333 <struct>jniNativeInterface</struct>
9334 </allocbuf>
9335 <description>
9336 On return, <code>*function_table</code>
9337 points a newly allocated copy of the JNI function table.
9338 </description>
9339 </param>
9340 </parameters>
9341 <errors>
9342 </errors>
9343 </function>
9344
9345 </category>
9346
9347 <category id="eventManagement" label="Event Management">
9348
9349 <function id="SetEventCallbacks" jkernel="yes" phase="onload" num="122">
9350 <synopsis>Set Event Callbacks</synopsis>
9351 <description>
9352 Set the functions to be called for each event.
9353 The callbacks are specified by supplying a replacement function table.
9354 The function table is copied--changes to the local copy of the
9355 table have no effect.
9356 This is an atomic action, all callbacks are set at once.
9357 No events are sent before this function is called.
9358 When an entry is <code>NULL</code> or when the event is beyond
9359 <paramlink id="size_of_callbacks"></paramlink> no event is sent.
9360 Details on events are
9361 described <internallink id="EventSection">later</internallink> in this document.
9362 An event must be enabled and have a callback in order to be
9363 sent--the order in which this function and
9364 <functionlink id="SetEventNotificationMode"></functionlink>
9365 are called does not affect the result.
9366 </description>
9367 <origin>new</origin>
9368 <capabilities>
9369 </capabilities>
9370 <parameters>
9371 <param id="callbacks">
9372 <inptr>
9373 <struct>jvmtiEventCallbacks</struct>
9374 <nullok>remove the existing callbacks</nullok>
9375 </inptr>
9376 <description>
9377 The new event callbacks.
9378 </description>
9379 </param>
9380 <param id="size_of_callbacks">
9381 <jint min="0"/>
9382 <description>
9383 <code>sizeof(jvmtiEventCallbacks)</code>--for version
9384 compatibility.
9385 </description>
9386 </param>
9387 </parameters>
9388 <errors>
9389 </errors>
9390 </function>
9391
9392 <function id="SetEventNotificationMode" jkernel="yes" phase="onload" num="2">
9393 <synopsis>Set Event Notification Mode</synopsis>
9394 <description>
9395 Control the generation of events.
9396 <constants id="jvmtiEventMode" label="Event Enable/Disable" kind="enum">
9397 <constant id="JVMTI_ENABLE" num="1">
9398 If <paramlink id="mode"></paramlink> is <code>JVMTI_ENABLE</code>,
9399 the event <paramlink id="event_type"></paramlink> will be enabled
9400 </constant>
9401 <constant id="JVMTI_DISABLE" num="0">
9402 If <paramlink id="mode"></paramlink> is <code>JVMTI_DISABLE</code>,
9403 the event <paramlink id="event_type"></paramlink> will be disabled
9404 </constant>
9405 </constants>
9406 If <code>thread</code> is <code>NULL</code>,
9407 the event is enabled or disabled globally; otherwise, it is
9408 enabled or disabled for a particular thread.
9409 An event is generated for
9410 a particular thread if it is enabled either at the thread or global
9411 levels.
9412 <p/>
9413 See <internallink id="EventIndex">below</internallink> for information on specific events.
9414 <p/>
9415 The following events cannot be controlled at the thread
9416 level through this function.
9417 <ul>
9418 <li><eventlink id="VMInit"></eventlink></li>
9419 <li><eventlink id="VMStart"></eventlink></li>
9420 <li><eventlink id="VMDeath"></eventlink></li>
9421 <li><eventlink id="ThreadStart"></eventlink></li>
9422 <li><eventlink id="CompiledMethodLoad"></eventlink></li>
9423 <li><eventlink id="CompiledMethodUnload"></eventlink></li>
9424 <li><eventlink id="DynamicCodeGenerated"></eventlink></li>
9425 <li><eventlink id="DataDumpRequest"></eventlink></li>
9426 </ul>
9427 <p/>
9428 Initially, no events are enabled at either the thread level
9429 or the global level.
9430 <p/>
9431 Any needed capabilities (see Event Enabling Capabilities below) must be possessed
9432 before calling this function.
9433 <p/>
9434 Details on events are
9435 described <internallink id="EventSection">below</internallink>.
9436 </description>
9437 <origin>jvmdiClone</origin>
9438 <eventcapabilities></eventcapabilities>
9439 <parameters>
9440 <param id="mode">
9441 <enum>jvmtiEventMode</enum>
9442 <description>
9443 <code>JVMTI_ENABLE</code> or <code>JVMTI_DISABLE</code>
9444 </description>
9445 </param>
9446 <param id="event_type">
9447 <enum>jvmtiEvent</enum>
9448 <description>
9449 the event to control
9450 </description>
9451 </param>
9452 <param id="event_thread">
9453 <ptrtype>
9454 <jthread impl="noconvert"/>
9455 <nullok>event is controlled at the global level</nullok>
9456 </ptrtype>
9457 <description>
9458 The thread to control
9459 </description>
9460 </param>
9461 <param id="...">
9462 <varargs/>
9463 <description>
9464 for future expansion
9465 </description>
9466 </param>
9467 </parameters>
9468 <errors>
9469 <error id="JVMTI_ERROR_INVALID_THREAD">
9470 <paramlink id="event_thread"/> is non-<code>NULL</code> and is not a valid thread.
9471 </error>
9472 <error id="JVMTI_ERROR_THREAD_NOT_ALIVE">
9473 <paramlink id="event_thread"/> is non-<code>NULL</code> and is not live (has not been started or is now dead).
9474 </error>
9475 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
9476 thread level control was attempted on events which do not
9477 permit thread level control.
9478 </error>
9479 <error id="JVMTI_ERROR_MUST_POSSESS_CAPABILITY">
9480 The Required Event Enabling Capability is not possessed.
9481 </error>
9482 </errors>
9483 </function>
9484
9485 <function id="GenerateEvents" num="123">
9486 <synopsis>Generate Events</synopsis>
9487 <description>
9488 Generate events to represent the current state of the VM.
9489 For example, if <paramlink id="event_type"/> is
9490 <code>JVMTI_EVENT_COMPILED_METHOD_LOAD</code>,
9491 a <eventlink id="CompiledMethodLoad"></eventlink> event will be
9492 sent for each currently compiled method.
9493 Methods that were loaded and now have been unloaded are not sent.
9494 The history of what events have previously been sent does not
9495 effect what events are sent by this function--for example,
9496 all currently compiled methods
9497 will be sent each time this function is called.
9498 <p/>
9499 This function is useful when
9500 events may have been missed due to the agent attaching after program
9501 execution begins; this function generates the missed events.
9502 <p/>
9503 Attempts to execute Java programming language code or
9504 JNI functions may be paused until this function returns -
9505 so neither should be called from the thread sending the event.
9506 This function returns only after the missed events have been
9507 sent, processed and have returned.
9508 The event may be sent on a different thread than the thread
9509 on which the event occurred.
9510 The callback for the event must be set with
9511 <functionlink id="SetEventCallbacks"></functionlink>
9512 and the event must be enabled with
9513 <functionlink id="SetEventNotificationMode"></functionlink>
9514 or the events will not occur.
9515 If the VM no longer has the information to generate some or
9516 all of the requested events, the events are simply not sent -
9517 no error is returned.
9518 <p/>
9519 Only the following events are supported:
9520 <ul>
9521 <li><eventlink id="CompiledMethodLoad"></eventlink></li>
9522 <li><eventlink id="DynamicCodeGenerated"></eventlink></li>
9523 </ul>
9524 </description>
9525 <origin>new</origin>
9526 <capabilities>
9527 <capability id="can_generate_compiled_method_load_events"></capability>
9528 </capabilities>
9529 <parameters>
9530 <param id="event_type">
9531 <enum>jvmtiEvent</enum>
9532 <description>
9533 The type of event to generate. Must be one of these:
9534 <ul>
9535 <li><eventlink id="CompiledMethodLoad"><code>JVMTI_EVENT_COMPILED_METHOD_LOAD</code></eventlink></li>
9536 <li><eventlink id="DynamicCodeGenerated"><code>JVMTI_EVENT_DYNAMIC_CODE_GENERATED</code></eventlink></li>
9537 </ul>
9538 </description>
9539 </param>
9540 </parameters>
9541 <errors>
9542 <error id="JVMTI_ERROR_MUST_POSSESS_CAPABILITY">
9543 <paramlink id="event_type"/> is
9544 <eventlink id="CompiledMethodLoad"><code>JVMTI_EVENT_COMPILED_METHOD_LOAD</code></eventlink>
9545 and <fieldlink id="can_generate_compiled_method_load_events" struct="jvmtiCapabilities"></fieldlink>
9546 is <code>false</code>.
9547 </error>
9548 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
9549 <paramlink id="event_type"/> is other than
9550 <eventlink id="CompiledMethodLoad"><code>JVMTI_EVENT_COMPILED_METHOD_LOAD</code></eventlink>
9551 or <eventlink id="DynamicCodeGenerated"><code>JVMTI_EVENT_DYNAMIC_CODE_GENERATED</code></eventlink>.
9552 </error>
9553 </errors>
9554 </function>
9555
9556 </category>
9557
9558 <category id="extension" label="Extension Mechanism">
9559
9560 <intro>
9561 These functions
9562 allow a <jvmti/> implementation to provide functions and events
9563 beyond those defined in this specification.
9564 <p/>
9565 Both extension functions and extension events have parameters
9566 each of which has a 'type' and 'kind' chosen from the following tables:
9567
9568 <constants id="jvmtiParamTypes" label="Extension Function/Event Parameter Types" kind="enum">
9569 <constant id="JVMTI_TYPE_JBYTE" num="101">
9570 Java programming language primitive type - <code>byte</code>.
9571 JNI type <code>jbyte</code>.
9572 </constant>
9573 <constant id="JVMTI_TYPE_JCHAR" num="102">
9574 Java programming language primitive type - <code>char</code>.
9575 JNI type <code>jchar</code>.
9576 </constant>
9577 <constant id="JVMTI_TYPE_JSHORT" num="103">
9578 Java programming language primitive type - <code>short</code>.
9579 JNI type <code>jshort</code>.
9580 </constant>
9581 <constant id="JVMTI_TYPE_JINT" num="104">
9582 Java programming language primitive type - <code>int</code>.
9583 JNI type <datalink id="jint"></datalink>.
9584 </constant>
9585 <constant id="JVMTI_TYPE_JLONG" num="105">
9586 Java programming language primitive type - <code>long</code>.
9587 JNI type <datalink id="jlong"></datalink>.
9588 </constant>
9589 <constant id="JVMTI_TYPE_JFLOAT" num="106">
9590 Java programming language primitive type - <code>float</code>.
9591 JNI type <datalink id="jfloat"></datalink>.
9592 </constant>
9593 <constant id="JVMTI_TYPE_JDOUBLE" num="107">
9594 Java programming language primitive type - <code>double</code>.
9595 JNI type <datalink id="jdouble"></datalink>.
9596 </constant>
9597 <constant id="JVMTI_TYPE_JBOOLEAN" num="108">
9598 Java programming language primitive type - <code>boolean</code>.
9599 JNI type <datalink id="jboolean"></datalink>.
9600 </constant>
9601 <constant id="JVMTI_TYPE_JOBJECT" num="109">
9602 Java programming language object type - <code>java.lang.Object</code>.
9603 JNI type <datalink id="jobject"></datalink>.
9604 Returned values are JNI local references and must be managed.
9605 </constant>
9606 <constant id="JVMTI_TYPE_JTHREAD" num="110">
9607 Java programming language object type - <code>java.lang.Thread</code>.
9608 <jvmti/> type <datalink id="jthread"></datalink>.
9609 Returned values are JNI local references and must be managed.
9610 </constant>
9611 <constant id="JVMTI_TYPE_JCLASS" num="111">
9612 Java programming language object type - <code>java.lang.Class</code>.
9613 JNI type <datalink id="jclass"></datalink>.
9614 Returned values are JNI local references and must be managed.
9615 </constant>
9616 <constant id="JVMTI_TYPE_JVALUE" num="112">
9617 Union of all Java programming language primitive and object types -
9618 JNI type <datalink id="jvalue"></datalink>.
9619 Returned values which represent object types are JNI local references and must be managed.
9620 </constant>
9621 <constant id="JVMTI_TYPE_JFIELDID" num="113">
9622 Java programming language field identifier -
9623 JNI type <datalink id="jfieldID"></datalink>.
9624 </constant>
9625 <constant id="JVMTI_TYPE_JMETHODID" num="114">
9626 Java programming language method identifier -
9627 JNI type <datalink id="jmethodID"></datalink>.
9628 </constant>
9629 <constant id="JVMTI_TYPE_CCHAR" num="115">
9630 C programming language type - <code>char</code>.
9631 </constant>
9632 <constant id="JVMTI_TYPE_CVOID" num="116">
9633 C programming language type - <code>void</code>.
9634 </constant>
9635 <constant id="JVMTI_TYPE_JNIENV" num="117">
9636 JNI environment - <code>JNIEnv</code>.
9637 Should be used with the correct <datalink id="jvmtiParamKind"/> to make it a pointer type.
9638 </constant>
9639 </constants>
9640
9641 <constants id="jvmtiParamKind" label="Extension Function/Event Parameter Kinds" kind="enum">
9642 <constant id="JVMTI_KIND_IN" num="91">
9643 Ingoing argument - <code>foo</code>.
9644 </constant>
9645 <constant id="JVMTI_KIND_IN_PTR" num="92">
9646 Ingoing pointer argument - <code>const foo*</code>.
9647 </constant>
9648 <constant id="JVMTI_KIND_IN_BUF" num="93">
9649 Ingoing array argument - <code>const foo*</code>.
9650 </constant>
9651 <constant id="JVMTI_KIND_ALLOC_BUF" num="94">
9652 Outgoing allocated array argument - <code>foo**</code>.
9653 Free with <code>Deallocate</code>.
9654 </constant>
9655 <constant id="JVMTI_KIND_ALLOC_ALLOC_BUF" num="95">
9656 Outgoing allocated array of allocated arrays argument - <code>foo***</code>.
9657 Free with <code>Deallocate</code>.
9658 </constant>
9659 <constant id="JVMTI_KIND_OUT" num="96">
9660 Outgoing argument - <code>foo*</code>.
9661 </constant>
9662 <constant id="JVMTI_KIND_OUT_BUF" num="97">
9663 Outgoing array argument (pre-allocated by agent) - <code>foo*</code>.
9664 Do not <code>Deallocate</code>.
9665 </constant>
9666 </constants>
9667
9668 </intro>
9669
9670 <typedef id="jvmtiParamInfo" label="Extension Function/Event Parameter Info">
9671 <field id="name">
9672 <allocfieldbuf><char/></allocfieldbuf>
9673 <description>
9674 The parameter name, encoded as a
9675 <internallink id="mUTF">modified UTF-8</internallink> string
9676 </description>
9677 </field>
9678 <field id="kind">
9679 <enum>jvmtiParamKind</enum>
9680 <description>
9681 The kind of the parameter - type modifiers
9682 </description>
9683 </field>
9684 <field id="base_type">
9685 <enum>jvmtiParamTypes</enum>
9686 <description>
9687 The base type of the parameter - modified by <code>kind</code>
9688 </description>
9689 </field>
9690 <field id="null_ok">
9691 <jboolean/>
9692 <description>
9693 Is a <code>NULL</code> argument permitted? Applies only to pointer and object types.
9694 </description>
9695 </field>
9696 </typedef>
9697
9698 <callback id="jvmtiExtensionFunction">
9699 <enum>jvmtiError</enum>
9700 <synopsis>Extension Function</synopsis>
9701 <description>
9702 This is the implementation-specific extension function.
9703 </description>
9704 <parameters>
9705 <param id="jvmti_env">
9706 <outptr>
9707 <struct>jvmtiEnv</struct>
9708 </outptr>
9709 <description>
9710 The <jvmti/> environment is the only fixed parameter for extension functions.
9711 </description>
9712 </param>
9713 <param id="...">
9714 <varargs/>
9715 <description>
9716 The extension function-specific parameters
9717 </description>
9718 </param>
9719 </parameters>
9720 </callback>
9721
9722 <function id="GetExtensionFunctions" phase="onload" num="124">
9723 <synopsis>Get Extension Functions</synopsis>
9724
9725 <typedef id="jvmtiExtensionFunctionInfo" label="Extension Function Info">
9726 <field id="func">
9727 <ptrtype>
9728 <struct>jvmtiExtensionFunction</struct>
9729 </ptrtype>
9730 <description>
9731 The actual function to call
9732 </description>
9733 </field>
9734 <field id="id">
9735 <allocfieldbuf><char/></allocfieldbuf>
9736 <description>
9737 The identifier for the extension function, encoded as a
9738 <internallink id="mUTF">modified UTF-8</internallink> string.
9739 Uses package name conventions.
9740 For example, <code>com.sun.hotspot.bar</code>
9741 </description>
9742 </field>
9743 <field id="short_description">
9744 <allocfieldbuf><char/></allocfieldbuf>
9745 <description>
9746 A one sentence description of the function, encoded as a
9747 <internallink id="mUTF">modified UTF-8</internallink> string.
9748 </description>
9749 </field>
9750 <field id="param_count">
9751 <jint/>
9752 <description>
9753 The number of parameters excluding <code>jvmtiEnv *jvmti_env</code>
9754 </description>
9755 </field>
9756 <field id="params">
9757 <allocfieldbuf outcount="param_count">
9758 <struct>jvmtiParamInfo</struct>
9759 </allocfieldbuf>
9760 <description>
9761 Array of
9762 <fieldlink id="param_count" struct="jvmtiExtensionFunctionInfo"></fieldlink>
9763 parameters (<code>jvmtiEnv *jvmti_env</code> excluded)
9764 </description>
9765 </field>
9766 <field id="error_count">
9767 <jint/>
9768 <description>
9769 The number of possible error returns (excluding universal errors)
9770 </description>
9771 </field>
9772 <field id="errors">
9773 <allocfieldbuf outcount="error_count">
9774 <enum>jvmtiError</enum>
9775 </allocfieldbuf>
9776 <description>
9777 Array of <fieldlink id="error_count" struct="jvmtiExtensionFunctionInfo"></fieldlink>
9778 possible errors
9779 </description>
9780 </field>
9781 </typedef>
9782
9783 <description>
9784 Returns the set of extension functions.
9785 </description>
9786 <origin>new</origin>
9787 <capabilities>
9788 </capabilities>
9789 <parameters>
9790 <param id="extension_count_ptr">
9791 <outptr><jint/></outptr>
9792 <description>
9793 On return, points to the number of extension functions
9794 </description>
9795 </param>
9796 <param id="extensions">
9797 <allocbuf outcount="extension_count_ptr"><struct>jvmtiExtensionFunctionInfo</struct></allocbuf>
9798 <description>
9799 Returns an array of extension function info, one per function
9800 </description>
9801 </param>
9802 </parameters>
9803 <errors>
9804 </errors>
9805 </function>
9806
9807 <function id="GetExtensionEvents" phase="onload" num="125">
9808 <synopsis>Get Extension Events</synopsis>
9809
9810 <typedef id="jvmtiExtensionEventInfo" label="Extension Event Info">
9811 <field id="extension_event_index">
9812 <jint/>
9813 <description>
9814 The identifying index of the event
9815 </description>
9816 </field>
9817 <field id="id">
9818 <allocfieldbuf><char/></allocfieldbuf>
9819 <description>
9820 The identifier for the extension event, encoded as a
9821 <internallink id="mUTF">modified UTF-8</internallink> string.
9822 Uses package name conventions.
9823 For example, <code>com.sun.hotspot.bar</code>
9824 </description>
9825 </field>
9826 <field id="short_description">
9827 <allocfieldbuf><char/></allocfieldbuf>
9828 <description>
9829 A one sentence description of the event, encoded as a
9830 <internallink id="mUTF">modified UTF-8</internallink> string.
9831 </description>
9832 </field>
9833 <field id="param_count">
9834 <jint/>
9835 <description>
9836 The number of parameters excluding <code>jvmtiEnv *jvmti_env</code>
9837 </description>
9838 </field>
9839 <field id="params">
9840 <allocfieldbuf outcount="param_count">
9841 <struct>jvmtiParamInfo</struct>
9842 </allocfieldbuf>
9843 <description>
9844 Array of
9845 <fieldlink id="param_count" struct="jvmtiExtensionEventInfo"></fieldlink>
9846 parameters (<code>jvmtiEnv *jvmti_env</code> excluded)
9847 </description>
9848 </field>
9849 </typedef>
9850
9851 <description>
9852 Returns the set of extension events.
9853 </description>
9854 <origin>new</origin>
9855 <capabilities>
9856 </capabilities>
9857 <parameters>
9858 <param id="extension_count_ptr">
9859 <outptr><jint/></outptr>
9860 <description>
9861 On return, points to the number of extension events
9862 </description>
9863 </param>
9864 <param id="extensions">
9865 <allocbuf outcount="extension_count_ptr"><struct>jvmtiExtensionEventInfo</struct></allocbuf>
9866 <description>
9867 Returns an array of extension event info, one per event
9868 </description>
9869 </param>
9870 </parameters>
9871 <errors>
9872 </errors>
9873 </function>
9874
9875 <callback id="jvmtiExtensionEvent">
9876 <void/>
9877 <synopsis>Extension Event</synopsis>
9878 <description>
9879 This is the implementation-specific event.
9880 The event handler is set with
9881 <functionlink id="SetExtensionEventCallback"/>.
9882 <p/>
9883 Event handlers for extension events must be declared varargs to match this definition.
9884 Failure to do so could result in calling convention mismatch and undefined behavior
9885 on some platforms.
9886 <p/>
9887 For example, if the <code>jvmtiParamInfo</code>
9888 returned by <functionlink id="GetExtensionEvents"/> indicates that
9889 there is a <code>jint</code> parameter, the event handler should be
9890 declared:
9891 <example>
9892 void JNICALL myHandler(jvmtiEnv* jvmti_env, jint myInt, ...)
9893 </example>
9894 Note the terminal "<code>...</code>" which indicates varargs.
9895 </description>
9896 <parameters>
9897 <param id="jvmti_env">
9898 <outptr>
9899 <struct>jvmtiEnv</struct>
9900 </outptr>
9901 <description>
9902 The <jvmti/> environment is the only fixed parameter for extension events.
9903 </description>
9904 </param>
9905 <param id="...">
9906 <varargs/>
9907 <description>
9908 The extension event-specific parameters
9909 </description>
9910 </param>
9911 </parameters>
9912 </callback>
9913
9914 <function id="SetExtensionEventCallback" phase="onload" num="126">
9915 <synopsis>Set Extension Event Callback</synopsis>
9916
9917 <description>
9918 Sets the callback function for an extension event and
9919 enables the event. Or, if the callback is <code>NULL</code>, disables
9920 the event. Note that unlike standard events, setting
9921 the callback and enabling the event are a single operation.
9922 </description>
9923 <origin>new</origin>
9924 <capabilities>
9925 </capabilities>
9926 <parameters>
9927 <param id="extension_event_index">
9928 <jint/>
9929 <description>
9930 Identifies which callback to set.
9931 This index is the
9932 <fieldlink id="extension_event_index" struct="jvmtiExtensionEventInfo"></fieldlink>
9933 field of
9934 <datalink id="jvmtiExtensionEventInfo"/>.
9935 </description>
9936 </param>
9937 <param id="callback">
9938 <ptrtype>
9939 <struct>jvmtiExtensionEvent</struct>
9940 <nullok>disable the event</nullok>
9941 </ptrtype>
9942 <description>
9943 If <code>callback</code> is non-<code>NULL</code>,
9944 set <code>callback</code> to be the event callback function
9945 and enable the event.
9946 </description>
9947 </param>
9948 </parameters>
9949 <errors>
9950 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
9951 <paramlink id="extension_event_index"/> is not an
9952 <fieldlink id="extension_event_index"
9953 struct="jvmtiExtensionEventInfo"/>
9954 returned by
9955 <functionlink id="GetExtensionEvents"/>
9956 </error>
9957 </errors>
9958 </function>
9959
9960 </category>
9961
9962 <category id="capability" label="Capability">
9963
9964 <intro>
9965 The capabilities functions allow you to change the
9966 functionality available to <jvmti/>--that is,
9967 which <jvmti/>
9968 functions can be called, what events can be generated,
9969 and what functionality these events and functions can
9970 provide.
9971 <p/>
9972 The "Capabilities" section of each function and event describe which
9973 capabilities, if any, they are associated with. "Required Functionality"
9974 means it is available for use and no capabilities must be added to use it.
9975 "Optional Functionality" means the agent must possess the capability
9976 before it can be used.
9977 To possess a capability, the agent must
9978 <functionlink id="AddCapabilities">add the capability</functionlink>.
9979 "Optional Features" describe capabilities which,
9980 if added, extend the feature set.
9981 <p/>
9982 The potentially available capabilities of each <jvmti/> implementation are different.
9983 Depending on the implementation, a capability:
9984 <ul>
9985 <li>may never be added</li>
9986 <li>may be added in either the <code>OnLoad</code> or live phase in any environment</li>
9987 <li>may be added only during the <code>OnLoad</code> phase</li>
9988 <li>may be possessed by only one environment at a time</li>
9989 <li>may be possessed by only one environment at a time,
9990 and only during the <code>OnLoad</code> phase</li>
9991 <li>and so on ...</li>
9992 </ul>
9993 Frequently, the addition of a capability may incur a cost in execution speed, start up
9994 time, and/or memory footprint. Note that the overhead of using a capability
9995 is completely different than the overhead of possessing a capability.
9996 Take single stepping as an example. When single stepping is on (that
9997 is, when the event is enabled and thus actively sending events)
9998 the overhead of sending and processing an event
9999 on each instruction is huge in any implementation.
10000 However, the overhead of possessing the capability may be small or large,
10001 depending on the implementation. Also, when and if a capability is potentially
10002 available depends on the implementation. Some examples:
10003 <ul>
10004 <li>One VM might perform all execution by compiling bytecodes into
10005 native code and be unable to generate single step instructions.
10006 In this implementation the capability can not be added.</li>
10007 <li>Another VM may be able to switch execution to a single stepping
10008 interpreter at any time. In this implementation, having the capability has no
10009 overhead and could be added at any time.</li>
10010 <li>Yet another VM might be able to choose a bytecode compiling or single stepping capable interpreted
10011 execution engine at start up, but be unable to switch between them.
10012 In this implementation the capability would need to be added
10013 during the <code>OnLoad</code> phase (before bytecode
10014 execution begins) and would have a large impact on execution speed
10015 even if single stepping was never used.</li>
10016 <li>Still another VM might be able to add an "is single stepping on" check
10017 into compiled bytecodes or a generated interpreter. Again in this implementation
10018 the capability would need to be added during the <code>OnLoad</code> phase but the overhead (a test
10019 and branch on each instruction) would be considerably less.</li>
10020 </ul>
10021 <p/>
10022 Each <jvmti/> <internallink id="environments">environment</internallink>
10023 has its own set of capabilities.
10024 Initially, that set is empty.
10025 Any desired capability must be added.
10026 If possible, capabilities should be added during the <code>OnLoad</code> phase. For most
10027 virtual machines certain capabilities require special set up for
10028 the virtual machine and this set up must happen
10029 during the <code>OnLoad</code> phase, before the virtual machine begins execution.
10030 Once a capability is added, it can
10031 only be removed if explicitly relinquished by the environment.
10032 <p/>
10033 The agent can,
10034 <functionlink id="GetPotentialCapabilities">determine what
10035 capabilities this VM can potentially provide</functionlink>,
10036 <functionlink id="AddCapabilities">add the capabilities
10037 to be used</functionlink>,
10038 <functionlink id="RelinquishCapabilities">release capabilities
10039 which are no longer needed</functionlink>, and
10040 <functionlink id="GetCapabilities">examine the currently available
10041 capabilities</functionlink>.
10042 </intro>
10043
10044 <intro id="capabilityExamples" label="Capability Examples">
10045 For example, a freshly started agent (in the <code>OnLoad</code> function)
10046 wants to enable all possible capabilities.
10047 Note that, in general, this is not advisable as the agent may suffer
10048 a performance penalty for functionality it is not using.
10049 The code might look like this in C:
10050 <example>
10051 jvmtiCapabilities capa;
10052 jvmtiError err;
10053
10054 err = (*jvmti)->GetPotentialCapabilities(jvmti, &capa);
10055 if (err == JVMTI_ERROR_NONE) {
10056 err = (*jvmti)->AddCapabilities(jvmti, &capa);
10057 </example>
10058 For example, if an agent wants to check if it can get
10059 the bytecodes of a method (that is, it wants to check
10060 if it previously added this capability and has not
10061 relinquished it), the code might
10062 look like this in C:
10063 <example>
10064 jvmtiCapabilities capa;
10065 jvmtiError err;
10066
10067 err = (*jvmti)->GetCapabilities(jvmti, &capa);
10068 if (err == JVMTI_ERROR_NONE) {
10069 if (capa.can_get_bytecodes) { ... } }
10070 </example>
10071 </intro>
10072
10073 <capabilitiestypedef id="jvmtiCapabilities" label="The Capabilities Structure">
10074 <description>
10075 The functions in this category use this capabilities structure
10076 which contains boolean flags corresponding to each capability:
10077 </description>
10078 <capabilityfield id="can_tag_objects">
10079 <description>
10080 Can set and get tags, as described in the
10081 <internallink id="Heap">Heap category</internallink>.
10082 </description>
10083 </capabilityfield>
10084 <capabilityfield id="can_generate_field_modification_events">
10085 <description>
10086 Can set watchpoints on field modification -
10087 <functionlink id="SetFieldModificationWatch"></functionlink>
10088 </description>
10089 </capabilityfield>
10090 <capabilityfield id="can_generate_field_access_events">
10091 <description>
10092 Can set watchpoints on field access -
10093 <functionlink id="SetFieldAccessWatch"></functionlink>
10094 </description>
10095 </capabilityfield>
10096 <capabilityfield id="can_get_bytecodes">
10097 <description>
10098 Can get bytecodes of a method <functionlink id="GetBytecodes"></functionlink>
10099 </description>
10100 </capabilityfield>
10101 <capabilityfield id="can_get_synthetic_attribute">
10102 <description>
10103 Can test if a field or method is synthetic -
10104 <functionlink id="IsFieldSynthetic"></functionlink> and
10105 <functionlink id="IsMethodSynthetic"></functionlink>
10106 </description>
10107 </capabilityfield>
10108 <capabilityfield id="can_get_owned_monitor_info">
10109 <description>
10110 Can get information about ownership of monitors -
10111 <functionlink id="GetOwnedMonitorInfo"></functionlink>
10112 </description>
10113 </capabilityfield>
10114 <capabilityfield id="can_get_current_contended_monitor">
10115 <description>
10116 Can <functionlink id="GetCurrentContendedMonitor"></functionlink>
10117 </description>
10118 </capabilityfield>
10119 <capabilityfield id="can_get_monitor_info">
10120 <description>
10121 Can <functionlink id="GetObjectMonitorUsage"></functionlink>
10122 </description>
10123 </capabilityfield>
10124 <capabilityfield id="can_pop_frame">
10125 <description>
10126 Can pop frames off the stack - <functionlink id="PopFrame"></functionlink>
10127 </description>
10128 </capabilityfield>
10129 <capabilityfield id="can_redefine_classes">
10130 <description>
10131 Can redefine classes with <functionlink id="RedefineClasses"/>.
10132 </description>
10133 </capabilityfield>
10134 <capabilityfield id="can_signal_thread">
10135 <description>
10136 Can send stop or interrupt to threads
10137 </description>
10138 </capabilityfield>
10139 <capabilityfield id="can_get_source_file_name">
10140 <description>
10141 Can get the source file name of a class
10142 </description>
10143 </capabilityfield>
10144 <capabilityfield id="can_get_line_numbers">
10145 <description>
10146 Can get the line number table of a method
10147 </description>
10148 </capabilityfield>
10149 <capabilityfield id="can_get_source_debug_extension">
10150 <description>
10151 Can get the source debug extension of a class
10152 </description>
10153 </capabilityfield>
10154 <capabilityfield id="can_access_local_variables">
10155 <description>
10156 Can set and get local variables
10157 </description>
10158 </capabilityfield>
10159 <capabilityfield id="can_maintain_original_method_order">
10160 <description>
10161 Can return methods in the order they occur in the class file
10162 </description>
10163 </capabilityfield>
10164 <capabilityfield id="can_generate_single_step_events">
10165 <description>
10166 Can get <eventlink id="SingleStep">single step</eventlink> events
10167 </description>
10168 </capabilityfield>
10169 <capabilityfield id="can_generate_exception_events">
10170 <description>
10171 Can get <eventlink id="Exception">exception thrown</eventlink> and
10172 <eventlink id="ExceptionCatch">exception catch</eventlink> events
10173 </description>
10174 </capabilityfield>
10175 <capabilityfield id="can_generate_frame_pop_events">
10176 <description>
10177 Can <functionlink id="NotifyFramePop">set</functionlink> and thus get
10178 <eventlink id="FramePop"></eventlink> events
10179 </description>
10180 </capabilityfield>
10181 <capabilityfield id="can_generate_breakpoint_events">
10182 <description>
10183 Can <functionlink id="SetBreakpoint">set</functionlink> and thus get
10184 <eventlink id="Breakpoint"></eventlink> events
10185 </description>
10186 </capabilityfield>
10187 <capabilityfield id="can_suspend">
10188 <description>
10189 Can suspend and resume threads
10190 </description>
10191 </capabilityfield>
10192 <capabilityfield id="can_redefine_any_class">
10193 <description>
10194 Can modify (retransform or redefine) any modifiable class.
10195 See <functionlink id="IsModifiableClass"/>.
10196 </description>
10197 </capabilityfield>
10198 <capabilityfield id="can_get_current_thread_cpu_time">
10199 <description>
10200 Can <functionlink id="GetCurrentThreadCpuTime">get</functionlink>
10201 current thread CPU time
10202 </description>
10203 </capabilityfield>
10204 <capabilityfield id="can_get_thread_cpu_time">
10205 <description>
10206 Can <functionlink id="GetThreadCpuTime">get</functionlink>
10207 thread CPU time
10208 </description>
10209 </capabilityfield>
10210 <capabilityfield id="can_generate_method_entry_events"
10211 disp1="can_generate" disp2="_method_entry_events"
10212 >
10213 <description>
10214 Can generate method entry events on entering a method
10215 </description>
10216 </capabilityfield>
10217 <capabilityfield id="can_generate_method_exit_events"
10218 disp1="can_generate" disp2="_method_exit_events"
10219 >
10220 <description>
10221 Can generate method exit events on leaving a method
10222 </description>
10223 </capabilityfield>
10224 <capabilityfield id="can_generate_all_class_hook_events"
10225 disp1="can_generate" disp2="_all_class_hook_events"
10226 >
10227 <description>
10228 Can generate ClassFileLoadHook events for every loaded class.
10229 </description>
10230 </capabilityfield>
10231 <capabilityfield id="can_generate_compiled_method_load_events"
10232 disp1="can_generate" disp2="_compiled_method_load_events"
10233 >
10234 <description>
10235 Can generate events when a method is compiled or unloaded
10236 </description>
10237 </capabilityfield>
10238 <capabilityfield id="can_generate_monitor_events"
10239 disp1="can_generate" disp2="_monitor_events"
10240 >
10241 <description>
10242 Can generate events on monitor activity
10243 </description>
10244 </capabilityfield>
10245 <capabilityfield id="can_generate_vm_object_alloc_events"
10246 disp1="can_generate" disp2="_vm_object_alloc_events"
10247 >
10248 <description>
10249 Can generate events on VM allocation of an object
10250 </description>
10251 </capabilityfield>
10252 <capabilityfield id="can_generate_native_method_bind_events"
10253 disp1="can_generate" disp2="_native_method_bind_events"
10254 >
10255 <description>
10256 Can generate events when a native method is bound to its
10257 implementation
10258 </description>
10259 </capabilityfield>
10260 <capabilityfield id="can_generate_garbage_collection_events"
10261 disp1="can_generate" disp2="_garbage_collection_events"
10262 >
10263 <description>
10264 Can generate events when garbage collection begins or ends
10265 </description>
10266 </capabilityfield>
10267 <capabilityfield id="can_generate_object_free_events"
10268 disp1="can_generate" disp2="_object_free_events"
10269 >
10270 <description>
10271 Can generate events when the garbage collector frees an object
10272 </description>
10273 </capabilityfield>
10274 <capabilityfield id="can_force_early_return" since="1.1">
10275 <description>
10276 Can return early from a method, as described in the
10277 <internallink id="ForceEarlyReturn">Force Early Return category</internallink>.
10278 </description>
10279 </capabilityfield>
10280 <capabilityfield id="can_get_owned_monitor_stack_depth_info" since="1.1">
10281 <description>
10282 Can get information about owned monitors with stack depth -
10283 <functionlink id="GetOwnedMonitorStackDepthInfo"></functionlink>
10284 </description>
10285 </capabilityfield>
10286 <capabilityfield id="can_get_constant_pool" since="1.1">
10287 <description>
10288 Can get the constant pool of a class -
10289 <functionlink id="GetConstantPool"></functionlink>
10290 </description>
10291 </capabilityfield>
10292 <capabilityfield id="can_set_native_method_prefix" since="1.1">
10293 <description>
10294 Can set prefix to be applied when native method cannot be resolved -
10295 <functionlink id="SetNativeMethodPrefix"/> and
10296 <functionlink id="SetNativeMethodPrefixes"/>
10297 </description>
10298 </capabilityfield>
10299 <capabilityfield id="can_retransform_classes" since="1.1">
10300 <description>
10301 Can retransform classes with <functionlink id="RetransformClasses"/>.
10302 In addition to the restrictions imposed by the specific
10303 implementation on this capability (see the
10304 <internallink id="capability">Capability</internallink> section),
10305 this capability must be set before the
10306 <eventlink id="ClassFileLoadHook"/> event is enabled for the
10307 first time in this environment.
10308 An environment that possesses this capability at the time that
10309 <code>ClassFileLoadHook</code> is enabled for the first time is
10310 said to be <i>retransformation capable</i>.
10311 An environment that does not possess this capability at the time that
10312 <code>ClassFileLoadHook</code> is enabled for the first time is
10313 said to be <i>retransformation incapable</i>.
10314 </description>
10315 </capabilityfield>
10316 <capabilityfield id="can_retransform_any_class" since="1.1">
10317 <description>
10318 <functionlink id="RetransformClasses"/> can be called on any modifiable class.
10319 See <functionlink id="IsModifiableClass"/>.
10320 (<fieldlink id="can_retransform_classes" struct="jvmtiCapabilities"/>
10321 must also be set)
10322 </description>
10323 </capabilityfield>
10324 <capabilityfield id="can_generate_resource_exhaustion_heap_events" since="1.1">
10325 <description>
10326 Can generate events when the VM is unable to allocate memory from
10327 the <tm>Java</tm> platform heap.
10328 See <eventlink id="ResourceExhausted"/>.
10329 </description>
10330 </capabilityfield>
10331 <capabilityfield id="can_generate_resource_exhaustion_threads_events" since="1.1">
10332 <description>
10333 Can generate events when the VM is unable to create a thread.
10334 See <eventlink id="ResourceExhausted"/>.
10335 </description>
10336 </capabilityfield>
10337 <capabilityfield id="can_generate_early_vmstart" since="9">
10338 <description>
10339 Can generate the <code>VMStart</code> event early.
10340 See <eventlink id="VMStart"/>.
10341 </description>
10342 </capabilityfield>
10343 <capabilityfield id="can_generate_early_class_hook_events" since="9">
10344 <description>
10345 Can generate the <eventlink id="ClassFileLoadHook"/> events
10346 in the primordial phase. If this capability and
10347 <internallink id="jvmtiCapabilities.can_generate_all_class_hook_events">
10348 <code>can_generate_all_class_hook_events</code></internallink>
10349 are enabled then the <eventlink id="ClassFileLoadHook"/> events
10350 can be posted for classes loaded in the primordial phase.
10351 See <eventlink id="ClassFileLoadHook"/>.
10352 </description>
10353 </capabilityfield>
10354
10355 <capabilityfield id="can_sample_heap" since="9">
10356 <description>
10357 Can sample the heap.
10358 If this capability is enabled then the heap sampling methods can be called.
10359 </description>
10360 </capabilityfield>
10361 </capabilitiestypedef>
10362
10363 <function id="GetPotentialCapabilities" jkernel="yes" phase="onload" num="140">
10364 <synopsis>Get Potential Capabilities</synopsis>
10365 <description>
10366 Returns via <paramlink id="capabilities_ptr"></paramlink> the <jvmti/>
10367 features that can potentially be possessed by this environment
10368 at this time.
10369 The returned capabilities differ from the complete set of capabilities
10370 implemented by the VM in two cases: another environment possesses
10371 capabilities that can only be possessed by one environment, or the
10372 current <functionlink id="GetPhase">phase</functionlink> is live,
10373 and certain capabilities can only be added during the <code>OnLoad</code> phase.
10374 The <functionlink id="AddCapabilities"></functionlink> function
10375 may be used to set any or all or these capabilities.
10376 Currently possessed capabilities are included.
10377 <p/>
10378 Typically this function is used in the <code>OnLoad</code> function.
10379 Some virtual machines may allow a limited set of capabilities to be
10380 added in the live phase.
10381 In this case, the set of potentially available capabilities
10382 will likely differ from the <code>OnLoad</code> phase set.
10383 <p/>
10384 See the
10385 <internallink id="capabilityExamples">Capability Examples</internallink>.
10386 </description>
10387 <origin>new</origin>
10388 <capabilities>
10389 </capabilities>
10390 <parameters>
10391 <param id="capabilities_ptr">
10392 <outptr><struct>jvmtiCapabilities</struct></outptr>
10393 <description>
10394 On return, points to the <jvmti/> capabilities that may be added.
10395 </description>
10396 </param>
10397 </parameters>
10398 <errors>
10399 </errors>
10400 </function>
10401
10402 <elide>
10403 <function id="EstimateCostOfCapabilities" phase="onload" num="141">
10404 <synopsis>Estimate Cost Of Capabilities</synopsis>
10405 <description>
10406 <issue>There is strong opposition to this function. The concern is
10407 that it would be difficult or impossible to provide meaningful
10408 numbers, as the amount of impact is conditional on many factors
10409 that a single number could not represent. There is doubt that
10410 conditional implementations would be used or are even a good idea.
10411 The thought is that release documentation for the implementation
10412 would be the best means of exposing this information.
10413 Unless new arguments are presented, I intend to remove this
10414 function in the next revision.
10415 </issue>
10416 <p/>
10417 Return via the <paramlink id="time_impact_ptr"></paramlink> and
10418 <paramlink id="space_impact_ptr"></paramlink> an estimate of the impact
10419 of adding the capabilities pointed to by
10420 <paramlink id="capabilities_ptr"></paramlink>.
10421 The returned estimates are in percentage of additional overhead, thus
10422 a time impact of 100 mean the application might run
10423 at half the speed.
10424 The estimates are very rough approximations and are not guaranteed.
10425 Note also, that the estimates are of the impact of having the
10426 capability available--when and if it is used the impact may be
10427 much greater.
10428 Estimates can be for a single capability or for a set of
10429 capabilities. Note that the costs are not necessarily additive,
10430 adding support for one capability might make another available
10431 for free or conversely having two capabilities at once may
10432 have multiplicative impact.
10433 Estimates are relative to the current set of capabilities -
10434 that is, how much more impact given the currently possessed capabilities.
10435 <p/>
10436 Typically this function is used in the OnLoad function,
10437 some virtual machines may allow a limited set of capabilities to be
10438 added in the live phase.
10439 In this case, the set of potentially available capabilities
10440 will likely differ from the OnLoad phase set.
10441 <p/>
10442 See the
10443 <internallink id="capabilityExamples">Capability Examples</internallink>.
10444 </description>
10445 <origin>new</origin>
10446 <capabilities>
10447 </capabilities>
10448 <parameters>
10449 <param id="capabilities_ptr">
10450 <inptr><struct>jvmtiCapabilities</struct></inptr>
10451 <description>
10452 points to the <jvmti/> capabilities to evaluate.
10453 </description>
10454 </param>
10455 <param id="time_impact_ptr">
10456 <outptr><jint/></outptr>
10457 <description>
10458 On return, points to the estimated percentage increase in
10459 run time if this capability was added.
10460 </description>
10461 </param>
10462 <param id="space_impact_ptr">
10463 <outptr><jint/></outptr>
10464 <description>
10465 On return, points to the estimated percentage increase in
10466 memory space used if this capability was added.
10467 </description>
10468 </param>
10469 </parameters>
10470 <errors>
10471 <error id="JVMTI_ERROR_NOT_AVAILABLE">
10472 The desired capabilities are not even potentially available.
10473 </error>
10474 </errors>
10475 </function>
10476 </elide>
10477
10478 <function id="AddCapabilities" jkernel="yes" phase="onload" num="142">
10479 <synopsis>Add Capabilities</synopsis>
10480 <description>
10481 Set new capabilities by adding the capabilities
10482 whose values are set to one (<code>1</code>) in
10483 <code>*</code><paramlink id="capabilities_ptr"></paramlink>.
10484 All previous capabilities are retained.
10485 Typically this function is used in the <code>OnLoad</code> function.
10486 Some virtual machines may allow a limited set of capabilities to be
10487 added in the live phase.
10488 <p/>
10489 See the
10490 <internallink id="capabilityExamples">Capability Examples</internallink>.
10491 </description>
10492 <origin>new</origin>
10493 <capabilities>
10494 </capabilities>
10495 <parameters>
10496 <param id="capabilities_ptr">
10497 <inptr><struct>jvmtiCapabilities</struct></inptr>
10498 <description>
10499 Points to the <jvmti/> capabilities to add.
10500 </description>
10501 </param>
10502 </parameters>
10503 <errors>
10504 <error id="JVMTI_ERROR_NOT_AVAILABLE">
10505 The desired capabilities are not even potentially available.
10506 </error>
10507 </errors>
10508 </function>
10509
10510
10511 <function id="RelinquishCapabilities" phase="onload" num="143">
10512 <synopsis>Relinquish Capabilities</synopsis>
10513 <description>
10514 Relinquish the capabilities
10515 whose values are set to one (<code>1</code>) in
10516 <code>*</code><paramlink id="capabilities_ptr"></paramlink>.
10517 Some implementations may allow only one environment to have a capability
10518 (see the <internallink id="capability">capability introduction</internallink>).
10519 This function releases capabilities
10520 so that they may be used by other agents.
10521 All other capabilities are retained.
10522 The capability will no longer be present in <functionlink id="GetCapabilities"></functionlink>.
10523 Attempting to relinquish a capability that the agent does not possess is not an error.
10524 <issue>
10525 It is possible for the agent to be actively using capabilities
10526 which are being relinquished. For example, a thread is currently
10527 suspended and can_suspend is being relinquished or an event is currently
10528 enabled and can_generate_whatever is being relinquished.
10529 There are three possible ways we could spec this:
10530 <ul>
10531 <li>relinquish automatically releases them</li>
10532 <li>relinquish checks and returns some error code if held</li>
10533 <li>it is the agent's responsibility and it is not checked</li>
10534 </ul>
10535 One of these should be chosen.
10536 </issue>
10537 </description>
10538 <origin>new</origin>
10539 <capabilities>
10540 </capabilities>
10541 <parameters>
10542 <param id="capabilities_ptr">
10543 <inptr><struct>jvmtiCapabilities</struct></inptr>
10544 <description>
10545 Points to the <jvmti/> capabilities to relinquish.
10546 </description>
10547 </param>
10548 </parameters>
10549 <errors>
10550 </errors>
10551 </function>
10552
10553
10554
10555 <function id="GetCapabilities" jkernel="yes" phase="any" num="89">
10556 <synopsis>Get Capabilities</synopsis>
10557 <description>
10558 Returns via <paramlink id="capabilities_ptr"></paramlink> the optional <jvmti/>
10559 features which this environment currently possesses.
10560 Each possessed capability is indicated by a one (<code>1</code>) in the
10561 corresponding field of the <internallink id="jvmtiCapabilities">capabilities
10562 structure</internallink>.
10563 An environment does not possess a capability unless it has been successfully added with
10564 <functionlink id="AddCapabilities"/>.
10565 An environment only loses possession of a capability if it has been relinquished with
10566 <functionlink id="RelinquishCapabilities"/>. Thus, this function returns the net result
10567 of the <code>AddCapabilities</code> and <code>RelinquishCapabilities</code> calls which
10568 have been made.
10569 <p/>
10570 See the
10571 <internallink id="capabilityExamples">Capability Examples</internallink>.
10572 </description>
10573 <origin>jvmdiClone</origin>
10574 <capabilities>
10575 </capabilities>
10576 <parameters>
10577 <param id="capabilities_ptr">
10578 <outptr><struct>jvmtiCapabilities</struct></outptr>
10579 <description>
10580 On return, points to the <jvmti/> capabilities.
10581 </description>
10582 </param>
10583 </parameters>
10584 <errors>
10585 </errors>
10586 </function>
10587
10588 </category>
10589
10590
10591 <category id="timers" label="Timers">
10592
10593 <intro>
10594 These functions provide timing information.
10595 The resolution at which the time is updated is not specified.
10596 They provides nanosecond precision, but not necessarily nanosecond accuracy.
10597 Details about the timers, such as their maximum values, can be accessed with
10598 the timer information functions.
10599 </intro>
10600
10601 <typedef id="jvmtiTimerInfo" label="Timer Info">
10602 <description>
10603 The information function for each timer returns this data structure.
10604 </description>
10605 <field id="max_value">
10606 <jlong/>
10607 <description>
10608 The maximum value the timer can reach.
10609 After this value is reached the timer wraps back to zero.
10610 This is an unsigned value. If tested or printed as a jlong (signed value)
10611 it may appear to be a negative number.
10612 </description>
10613 </field>
10614 <field id="may_skip_forward">
10615 <jboolean/>
10616 <description>
10617 If true, the timer can be externally adjusted and as a result skip forward.
10618 If false, the timer value will never increase faster than real time.
10619 </description>
10620 </field>
10621 <field id="may_skip_backward">
10622 <jboolean/>
10623 <description>
10624 If true, the timer can be externally adjusted and as a result skip backward.
10625 If false, the timer value will be monotonically increasing.
10626 </description>
10627 </field>
10628 <field id="kind">
10629 <enum>jvmtiTimerKind</enum>
10630 <description>
10631 The kind of timer.
10632 On a platform that does not distinguish between user and system time, <datalink
10633 id="JVMTI_TIMER_TOTAL_CPU"><code>JVMTI_TIMER_TOTAL_CPU</code></datalink>
10634 is returned.
10635 </description>
10636 </field>
10637 <field id="reserved1">
10638 <jlong/>
10639 <description>
10640 Reserved for future use.
10641 </description>
10642 </field>
10643 <field id="reserved2">
10644 <jlong/>
10645 <description>
10646 Reserved for future use.
10647 </description>
10648 </field>
10649 </typedef>
10650
10651 <intro>
10652 Where the timer kind is --
10653
10654 <constants id="jvmtiTimerKind" label="Timer Kinds" kind="enum">
10655 <constant id="JVMTI_TIMER_USER_CPU" num="30">
10656 CPU time that a thread is in user mode.
10657 </constant>
10658 <constant id="JVMTI_TIMER_TOTAL_CPU" num="31">
10659 CPU time that a thread is in user or system mode.
10660 </constant>
10661 <constant id="JVMTI_TIMER_ELAPSED" num="32">
10662 Elapsed time.
10663 </constant>
10664 </constants>
10665 </intro>
10666
10667 <function id="GetCurrentThreadCpuTimerInfo" callbacksafe="safe" impl="innative notrace" phase="start" num="134">
10668 <synopsis>Get Current Thread CPU Timer Information</synopsis>
10669 <description>
10670 Get information about the
10671 <functionlink id="GetCurrentThreadCpuTime"/> timer.
10672 The fields of the <datalink id="jvmtiTimerInfo"/> structure
10673 are filled in with details about the timer.
10674 This information is specific to the platform and the implementation of
10675 <functionlink id="GetCurrentThreadCpuTime"/> and thus
10676 does not vary by thread nor does it vary
10677 during a particular invocation of the VM.
10678 <p/>
10679 Note that the implementations of <functionlink id="GetCurrentThreadCpuTime"/>
10680 and <functionlink id="GetThreadCpuTime"/> may differ, and thus the values
10681 returned by <code>GetCurrentThreadCpuTimerInfo</code>
10682 and <functionlink id="GetThreadCpuTimerInfo"/>
10683 may differ -- see <functionlink id="GetCurrentThreadCpuTime"/> for more information.
10684 </description>
10685 <origin>new</origin>
10686 <capabilities>
10687 <required id="can_get_current_thread_cpu_time">
10688 Can get current thread CPU time.
10689 </required>
10690 </capabilities>
10691 <parameters>
10692 <param id="info_ptr">
10693 <outptr><struct>jvmtiTimerInfo</struct></outptr>
10694 <description>
10695 On return, filled with information describing the time
10696 returned by <functionlink id="GetCurrentThreadCpuTime"/>.
10697 </description>
10698 </param>
10699 </parameters>
10700 <errors>
10701 </errors>
10702 </function>
10703
10704 <function id="GetCurrentThreadCpuTime" callbacksafe="safe" impl="innative notrace" phase="start" num="135">
10705 <synopsis>Get Current Thread CPU Time</synopsis>
10706 <description>
10707 Return the CPU time utilized by the current thread.
10708 <p/>
10709 Note that the <functionlink id="GetThreadCpuTime"/>
10710 function provides CPU time for any thread, including
10711 the current thread. <code>GetCurrentThreadCpuTime</code>
10712 exists to support platforms which cannot
10713 supply CPU time for threads other than the current
10714 thread or which have more accurate information for
10715 the current thread (see
10716 <functionlink id="GetCurrentThreadCpuTimerInfo"/> vs
10717 <functionlink id="GetThreadCpuTimerInfo"/>).
10718 On many platforms this call will be equivalent to:
10719 <example>
10720 GetThreadCpuTime(env, NULL, nanos_ptr)
10721 </example>
10722 </description>
10723 <origin>new</origin>
10724 <capabilities>
10725 <required id="can_get_current_thread_cpu_time">
10726 Can get current thread CPU time.
10727 <p/>
10728 If this capability is enabled after threads have started,
10729 the implementation may choose any time up
10730 to and including the time that the capability is enabled
10731 as the point where CPU time collection starts.
10732 <p/>
10733 This capability must be potentially available on any
10734 platform where
10735 <internallink id="jvmtiCapabilities.can_get_thread_cpu_time"><code>can_get_thread_cpu_time</code></internallink>
10736 is potentially available.
10737 </required>
10738 </capabilities>
10739 <parameters>
10740 <param id="nanos_ptr">
10741 <outptr><jlong/></outptr>
10742 <description>
10743 On return, points to the CPU time used by this thread
10744 in nanoseconds.
10745 This is an unsigned value. If tested or printed as a jlong (signed value)
10746 it may appear to be a negative number.
10747 </description>
10748 </param>
10749 </parameters>
10750 <errors>
10751 </errors>
10752 </function>
10753
10754 <function id="GetThreadCpuTimerInfo" num="136">
10755 <synopsis>Get Thread CPU Timer Information</synopsis>
10756 <description>
10757 Get information about the
10758 <functionlink id="GetThreadCpuTime"/> timer.
10759 The fields of the <datalink id="jvmtiTimerInfo"/> structure
10760 are filled in with details about the timer.
10761 This information is specific to the platform and the implementation of
10762 <functionlink id="GetThreadCpuTime"/> and thus
10763 does not vary by thread nor does it vary
10764 during a particular invocation of the VM.
10765 <p/>
10766 Note that the implementations of <functionlink id="GetCurrentThreadCpuTime"/>
10767 and <functionlink id="GetThreadCpuTime"/> may differ, and thus the values
10768 returned by <functionlink id="GetCurrentThreadCpuTimerInfo"/>
10769 and <code>GetThreadCpuTimerInfo</code>
10770 may differ -- see <functionlink id="GetCurrentThreadCpuTime"/> for more information.
10771 </description>
10772 <origin>new</origin>
10773 <capabilities>
10774 <required id="can_get_thread_cpu_time">
10775 Can get thread CPU time.
10776 </required>
10777 </capabilities>
10778 <parameters>
10779 <param id="info_ptr">
10780 <outptr><struct>jvmtiTimerInfo</struct></outptr>
10781 <description>
10782 On return, filled with information describing the time
10783 returned by <functionlink id="GetThreadCpuTime"/>.
10784 </description>
10785 </param>
10786 </parameters>
10787 <errors>
10788 </errors>
10789 </function>
10790
10791 <function id="GetThreadCpuTime" num="137">
10792 <synopsis>Get Thread CPU Time</synopsis>
10793 <description>
10794 Return the CPU time utilized by the specified thread.
10795 <p/>
10796 Get information about this timer with
10797 <functionlink id="GetThreadCpuTimerInfo"/>.
10798 </description>
10799 <origin>new</origin>
10800 <capabilities>
10801 <required id="can_get_thread_cpu_time">
10802 Can get thread CPU time.
10803 <p/>
10804 If this capability is enabled after threads have started,
10805 the implementation may choose any time up
10806 to and including the time that the capability is enabled
10807 as the point where CPU time collection starts.
10808 </required>
10809 </capabilities>
10810 <parameters>
10811 <param id="thread">
10812 <jthread null="current"/>
10813 <description>
10814 The thread to query.
10815 </description>
10816 </param>
10817 <param id="nanos_ptr">
10818 <outptr><jlong/></outptr>
10819 <description>
10820 On return, points to the CPU time used by the specified thread
10821 in nanoseconds.
10822 This is an unsigned value. If tested or printed as a jlong (signed value)
10823 it may appear to be a negative number.
10824 </description>
10825 </param>
10826 </parameters>
10827 <errors>
10828 </errors>
10829 </function>
10830
10831 <function id="GetTimerInfo" phase="any" callbacksafe="safe" num="138">
10832 <synopsis>Get Timer Information</synopsis>
10833 <description>
10834 Get information about the
10835 <functionlink id="GetTime"/> timer.
10836 The fields of the <datalink id="jvmtiTimerInfo"/> structure
10837 are filled in with details about the timer.
10838 This information will not change during a particular invocation of the VM.
10839 </description>
10840 <origin>new</origin>
10841 <capabilities>
10842 </capabilities>
10843 <parameters>
10844 <param id="info_ptr">
10845 <outptr><struct>jvmtiTimerInfo</struct></outptr>
10846 <description>
10847 On return, filled with information describing the time
10848 returned by <functionlink id="GetTime"/>.
10849 </description>
10850 </param>
10851 </parameters>
10852 <errors>
10853 </errors>
10854 </function>
10855
10856 <function id="GetTime" phase="any" callbacksafe="safe" num="139">
10857 <synopsis>Get Time</synopsis>
10858 <description>
10859 Return the current value of the system timer, in nanoseconds.
10860 <p/>
10861 The value returned represents nanoseconds since some fixed but
10862 arbitrary time (perhaps in the future, so values may be
10863 negative). This function provides nanosecond precision, but not
10864 necessarily nanosecond accuracy. No guarantees are made about
10865 how frequently values change.
10866 <p/>
10867 Get information about this timer with
10868 <functionlink id="GetTimerInfo"/>.
10869 </description>
10870 <origin>new</origin>
10871 <capabilities>
10872 </capabilities>
10873 <parameters>
10874 <param id="nanos_ptr">
10875 <outptr><jlong/></outptr>
10876 <description>
10877 On return, points to the time in nanoseconds.
10878 This is an unsigned value. If tested or printed as a jlong (signed value)
10879 it may appear to be a negative number.
10880 </description>
10881 </param>
10882 </parameters>
10883 <errors>
10884 </errors>
10885 </function>
10886
10887 <function id="GetAvailableProcessors" phase="any" num="144">
10888 <synopsis>Get Available Processors</synopsis>
10889 <description>
10890 Returns the number of processors available to the Java virtual machine.
10891 <p/>
10892 This value may change during a particular invocation of the virtual machine.
10893 Applications that are sensitive to the number of available processors should
10894 therefore occasionally poll this property.
10895 </description>
10896 <origin>new</origin>
10897 <capabilities>
10898 </capabilities>
10899 <parameters>
10900 <param id="processor_count_ptr">
10901 <outptr><jint/></outptr>
10902 <description>
10903 On return, points to the maximum number of processors available to the
10904 virtual machine; never smaller than one.
10905 </description>
10906 </param>
10907 </parameters>
10908 <errors>
10909 </errors>
10910 </function>
10911
10912 </category>
10913
10914
10915 <category id="classLoaderSearch" label="Class Loader Search">
10916
10917 <intro>
10918 These functions allow the agent to add to the locations that a class loader searches for a class.
10919 This is useful for installing instrumentation under the correct class loader.
10920 </intro>
10921
10922 <function id="AddToBootstrapClassLoaderSearch" jkernel="yes" phase="onload" num="149">
10923 <synopsis>Add To Bootstrap Class Loader Search</synopsis>
10924 <description>
10925 This function can be used to cause instrumentation classes to be defined by the
10926 bootstrap class loader. See <vmspec chapter="5.3.1"/>.
10927 After the bootstrap
10928 class loader unsuccessfully searches for a class, the specified platform-dependent
10929 search path <paramlink id="segment"/> will be searched as well. Only one segment may be specified in
10930 the <paramlink id="segment"/>. This function may be called multiple times to add multiple segments,
10931 the segments will be searched in the order that this function was called.
10932 <p/>
10933 In the <code>OnLoad</code> phase the function may be used to specify any platform-dependent
10934 search path segment to be searched after the bootstrap class loader unsuccessfully searches
10935 for a class. The segment is typically a directory or JAR file.
10936 <p/>
10937 In the live phase the <paramlink id="segment"/> may be used to specify any platform-dependent
10938 path to a <externallink id="jar/jar.html">
10939 JAR file</externallink>. The agent should take care that the JAR file does not
10940 contain any classes or resources other than those to be defined by the bootstrap
10941 class loader for the purposes of instrumentation.
10942 <p/>
10943 <vmspec/> specifies that a subsequent attempt to resolve a symbolic
10944 reference that the Java virtual machine has previously unsuccessfully attempted
10945 to resolve always fails with the same error that was thrown as a result of the
10946 initial resolution attempt. Consequently, if the JAR file contains an entry
10947 that corresponds to a class for which the Java virtual machine has
10948 unsuccessfully attempted to resolve a reference, then subsequent attempts to
10949 resolve that reference will fail with the same error as the initial attempt.
10950 </description>
10951 <origin>new</origin>
10952 <capabilities>
10953 </capabilities>
10954 <parameters>
10955 <param id="segment">
10956 <inbuf><char/></inbuf>
10957 <description>
10958 The platform-dependent search path segment, encoded as a
10959 <internallink id="mUTF">modified UTF-8</internallink> string.
10960 </description>
10961 </param>
10962 </parameters>
10963 <errors>
10964 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
10965 <paramlink id="segment"/> is an invalid path. In the live phase, anything other than an
10966 existing JAR file is an invalid path.
10967 </error>
10968 </errors>
10969 </function>
10970
10971 <function id="AddToSystemClassLoaderSearch" jkernel="yes" phase="onload" num="151" since="1.1">
10972 <synopsis>Add To System Class Loader Search</synopsis>
10973 <description>
10974 This function can be used to cause instrumentation classes to be
10975 defined by the system class loader. See <vmspec chapter="5.3.2"/>.
10976 After the class loader unsuccessfully searches for a class, the specified platform-dependent search
10977 path <paramlink id="segment"/> will be searched as well. Only one segment may be specified in the
10978 <paramlink id="segment"/>. This function may be called multiple times to add multiple segments, the
10979 segments will be searched in the order that this function was called.
10980 <p/>
10981 In the <code>OnLoad</code> phase the function may be used to specify any platform-dependent
10982 search path segment to be searched after the system class loader unsuccessfully searches
10983 for a class. The segment is typically a directory or JAR file.
10984 <p/>
10985 In the live phase the <paramlink id="segment"/> is a platform-dependent path to a
10986 <externallink id="jar/jar.html">JAR file</externallink> to be
10987 searched after the system class loader unsuccessfully searches for a class. The agent should
10988 take care that the JAR file does not contain any classes or resources other than those to be
10989 defined by the system class loader for the purposes of instrumentation.
10990 <p/>
10991 In the live phase the system class loader supports adding a JAR file to be searched if
10992 the system class loader implements a method name <code>appendToClassPathForInstrumentation</code>
10993 which takes a single parameter of type <code>java.lang.String</code>. The method is not required
10994 to have <code>public</code> access.
10995 <p/>
10996 <vmspec/> specifies that a subsequent attempt to resolve a symbolic
10997 reference that the Java virtual machine has previously unsuccessfully attempted
10998 to resolve always fails with the same error that was thrown as a result of the
10999 initial resolution attempt. Consequently, if the JAR file contains an entry
11000 that corresponds to a class for which the Java virtual machine has
11001 unsuccessfully attempted to resolve a reference, then subsequent attempts to
11002 resolve that reference will fail with the same error as the initial attempt.
11003 </description>
11004 <origin>new</origin>
11005 <capabilities>
11006 </capabilities>
11007 <parameters>
11008 <param id="segment">
11009 <inbuf><char/></inbuf>
11010 <description>
11011 The platform-dependent search path segment, encoded as a
11012 <internallink id="mUTF">modified UTF-8</internallink> string.
11013 </description>
11014 </param>
11015 </parameters>
11016 <errors>
11017 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
11018 <paramlink id="segment"/> is an invalid path. In the live phase, anything other than an
11019 existing JAR file is an invalid path.
11020 </error>
11021 <error id="JVMTI_ERROR_CLASS_LOADER_UNSUPPORTED">
11022 Operation not supported by the system class loader.
11023 </error>
11024 </errors>
11025 </function>
11026
11027 </category>
11028
11029
11030 <category id="props" label="System Properties">
11031
11032 <intro>
11033 These functions get and set system properties.
11034 </intro>
11035
11036 <function id="GetSystemProperties" phase="onload" num="130">
11037 <synopsis>Get System Properties</synopsis>
11038 <description>
11039 The list of VM system property keys which may be used with
11040 <functionlink id="GetSystemProperty"/> is returned.
11041 It is strongly recommended that virtual machines provide the
11042 following property keys:
11043 <ul>
11044 <li><code>java.vm.vendor</code></li>
11045 <li><code>java.vm.version</code></li>
11046 <li><code>java.vm.name</code></li>
11047 <li><code>java.vm.info</code></li>
11048 <li><code>java.library.path</code></li>
11049 <li><code>java.class.path</code></li>
11050 </ul>
11051 Provides access to system properties defined by and used
11052 by the VM.
11053 Properties set on the command-line are included.
11054 This allows getting and setting of these properties
11055 before the VM even begins executing bytecodes.
11056 Since this is a VM view of system properties, the set of available
11057 properties will usually be different than that
11058 in <code>java.lang.System.getProperties</code>.
11059 JNI method invocation may be used to access
11060 <code>java.lang.System.getProperties</code>.
11061 <p/>
11062 The set of properties may grow during execution.
11063 </description>
11064 <origin>new</origin>
11065 <capabilities>
11066 </capabilities>
11067 <parameters>
11068 <param id="count_ptr">
11069 <outptr><jint/></outptr>
11070 <description>
11071 On return, points to the number of property keys returned.
11072 </description>
11073 </param>
11074 <param id="property_ptr">
11075 <allocallocbuf outcount="count_ptr"><char/></allocallocbuf>
11076 <description>
11077 On return, points to an array of property keys, encoded as
11078 <internallink id="mUTF">modified UTF-8</internallink> strings.
11079 </description>
11080 </param>
11081 </parameters>
11082 <errors>
11083 </errors>
11084 </function>
11085
11086 <function id="GetSystemProperty" phase="onload" num="131">
11087 <synopsis>Get System Property</synopsis>
11088 <description>
11089 Return a VM system property value given the property key.
11090 <p/>
11091 The function <functionlink id="GetSystemProperties"/>
11092 returns the set of property keys which may be used.
11093 The properties which can be retrieved may grow during
11094 execution.
11095 <p/>
11096 Since this is a VM view of system properties, the values
11097 of properties may differ from that returned by
11098 <code>java.lang.System.getProperty(String)</code>.
11099 A typical VM might copy the values of the VM system
11100 properties into the <code>Properties</code> held by
11101 <code>java.lang.System</code> during the initialization
11102 of that class. Thereafter any changes to the VM system
11103 properties (with <functionlink id="SetSystemProperty"/>)
11104 or the <code>java.lang.System</code> system properties
11105 (with <code>java.lang.System.setProperty(String,String)</code>)
11106 would cause the values to diverge.
11107 JNI method invocation may be used to access
11108 <code>java.lang.System.getProperty(String)</code>.
11109 </description>
11110 <origin>new</origin>
11111 <capabilities>
11112 </capabilities>
11113 <parameters>
11114 <param id="property">
11115 <inbuf><char/></inbuf>
11116 <description>
11117 The key of the property to retrieve, encoded as a
11118 <internallink id="mUTF">modified UTF-8</internallink> string.
11119 </description>
11120 </param>
11121 <param id="value_ptr">
11122 <allocbuf><char/></allocbuf>
11123 <description>
11124 On return, points to the property value, encoded as a
11125 <internallink id="mUTF">modified UTF-8</internallink> string.
11126 </description>
11127 </param>
11128 </parameters>
11129 <errors>
11130 <error id="JVMTI_ERROR_NOT_AVAILABLE">
11131 This property is not available.
11132 Use <functionlink id="GetSystemProperties"/> to find available properties.
11133 </error>
11134 </errors>
11135 </function>
11136
11137 <function id="SetSystemProperty" phase="onloadOnly" num="132">
11138 <synopsis>Set System Property</synopsis>
11139 <description>
11140 Set a VM system property value.
11141 <p/>
11142 The function <functionlink id="GetSystemProperties"/>
11143 returns the set of property keys, some of these may be settable.
11144 See <functionlink id="GetSystemProperty"/>.
11145 </description>
11146 <origin>new</origin>
11147 <capabilities>
11148 </capabilities>
11149 <parameters>
11150 <param id="property">
11151 <inbuf><char/></inbuf>
11152 <description>
11153 The key of the property, encoded as a
11154 <internallink id="mUTF">modified UTF-8</internallink> string.
11155 </description>
11156 </param>
11157 <param id="value_ptr">
11158 <inbuf>
11159 <char/>
11160 <nullok>
11161 do not set the value, but return <errorlink id="JVMTI_ERROR_NOT_AVAILABLE"/>
11162 if the property is not writeable
11163 </nullok>
11164 </inbuf>
11165 <description>
11166 The property value to set, encoded as a
11167 <internallink id="mUTF">modified UTF-8</internallink> string.
11168 </description>
11169 </param>
11170 </parameters>
11171 <errors>
11172 <error id="JVMTI_ERROR_NOT_AVAILABLE">
11173 This property is not available or is not writeable.
11174 </error>
11175 </errors>
11176 </function>
11177
11178 </category>
11179
11180 <category id="general" label="General">
11181
11182 <intro>
11183 </intro>
11184
11185 <function id="GetPhase" jkernel="yes" phase="any" num="133">
11186 <synopsis>Get Phase</synopsis>
11187 <description>
11188 Return the current phase of VM execution.
11189 The phases proceed in sequence:
11190 <constants id="jvmtiPhase" label="Phases of execution" kind="enum">
11191 <constant id="JVMTI_PHASE_ONLOAD" num="1">
11192 <code>OnLoad</code> phase: while in the
11193 <internallink id="onload"><code>Agent_OnLoad</code></internallink>
11194 or, for statically linked agents, the <internallink id="onload">
11195 <code>Agent_OnLoad_<agent-lib-name>
11196 </code></internallink> function.
11197 </constant>
11198 <constant id="JVMTI_PHASE_PRIMORDIAL" num="2">
11199 Primordial phase: between return from <code>Agent_OnLoad</code>
11200 or <code>Agent_OnLoad_<agent-lib-name></code> and the
11201 <code>VMStart</code> event.
11202 </constant>
11203 <constant id="JVMTI_PHASE_START" num="6">
11204 Start phase: when the <eventlink id="VMStart"><code>VMStart</code></eventlink> event
11205 is sent and until the <code>VMInit</code> event is sent.
11206 </constant>
11207 <constant id="JVMTI_PHASE_LIVE" num="4">
11208 Live phase: when the <eventlink id="VMInit"><code>VMInit</code></eventlink> event is sent
11209 and until the <eventlink id="VMDeath"></eventlink> event returns.
11210 </constant>
11211 <constant id="JVMTI_PHASE_DEAD" num="8">
11212 Dead phase: after the <eventlink id="VMDeath"></eventlink> event returns or after
11213 start-up failure.
11214 </constant>
11215 </constants>
11216 In the case of start-up failure the VM will proceed directly to the dead
11217 phase skipping intermediate phases and neither a <code>VMInit</code> nor
11218 <code>VMDeath</code> event will be sent.
11219 <p/>
11220 Most <jvmti/> functions operate only in the live phase.
11221 The following functions operate in either the <code>OnLoad</code> or live phases:
11222 <functionphaselist phase="onload"/>
11223 The following functions operate in only the <code>OnLoad</code> phase:
11224 <functionphaselist phase="onloadOnly"/>
11225 The following functions operate in the start or live phases:
11226 <functionphaselist phase="start"/>
11227 The following functions operate in any phase:
11228 <functionphaselist phase="any"/>
11229 JNI functions (except the Invocation API) must only be used in the start or live phases.
11230 <p/>
11231 Most <jvmti/> events are sent only in the live phase.
11232 The following events operate in others phases:
11233 <eventphaselist phase="start"/>
11234 <eventphaselist phase="any"/>
11235 </description>
11236 <origin>new</origin>
11237 <capabilities>
11238 </capabilities>
11239 <parameters>
11240 <param id="phase_ptr">
11241 <outptr><enum>jvmtiPhase</enum></outptr>
11242 <description>
11243 On return, points to the phase.
11244 </description>
11245 </param>
11246 </parameters>
11247 <errors>
11248 </errors>
11249 </function>
11250
11251 <function id="DisposeEnvironment" jkernel="yes" phase="any" num="127">
11252 <synopsis>Dispose Environment</synopsis>
11253 <description>
11254 Shutdown a <jvmti/> connection created with JNI <code>GetEnv</code>
11255 (see <internallink id="environments"><jvmti/> Environments</internallink>).
11256 Dispose of any resources held by the environment.
11257 <issue>
11258 What resources are reclaimed? What is undone?
11259 Breakpoints,watchpoints removed?
11260 </issue>
11261 Threads suspended by this environment are not resumed by this call,
11262 this must be done explicitly by the agent.
11263 Memory allocated by this environment via calls to <jvmti/> functions
11264 is not released, this can be done explicitly by the agent
11265 by calling <functionlink id="Deallocate"/>.
11266 Raw monitors created by this environment are not destroyed,
11267 this can be done explicitly by the agent
11268 by calling <functionlink id="DestroyRawMonitor"/>.
11269 The state of threads waiting on raw monitors created by this environment
11270 are not affected.
11271 <p/>
11272 Any <functionlink id="SetNativeMethodPrefix">native method
11273 prefixes</functionlink> for this environment will be unset;
11274 the agent must remove any prefixed native methods before
11275 dispose is called.
11276 <p/>
11277 Any <internallink id="capability">capabilities</internallink>
11278 held by this environment are relinquished.
11279 <p/>
11280 Events enabled by this environment will no longer be sent, however
11281 event handlers currently running will continue to run. Caution must
11282 be exercised in the design of event handlers whose environment may
11283 be disposed and thus become invalid during their execution.
11284 <p/>
11285 This environment may not be used after this call.
11286 This call returns to the caller.
11287 </description>
11288 <origin>new</origin>
11289 <capabilities>
11290 </capabilities>
11291 <parameters>
11292 </parameters>
11293 <errors>
11294 </errors>
11295 </function>
11296
11297 <function id="SetEnvironmentLocalStorage" jkernel="yes" phase="any" callbacksafe="safe" impl="innative notrace" num="148">
11298 <synopsis>Set Environment Local Storage</synopsis>
11299 <description>
11300 The VM stores a pointer value associated with each environment.
11301 This pointer value is called <i>environment-local storage</i>.
11302 This value is <code>NULL</code> unless set with this function.
11303 Agents can allocate memory in which they store environment specific
11304 information. By setting environment-local storage it can then be
11305 accessed with
11306 <functionlink id="GetEnvironmentLocalStorage"></functionlink>.
11307 <p/>
11308 Called by the agent to set the value of the <jvmti/>
11309 environment-local storage. <jvmti/> supplies to the agent a pointer-size
11310 environment-local storage that can be used to record per-environment
11311 information.
11312 </description>
11313 <origin>new</origin>
11314 <capabilities>
11315 </capabilities>
11316 <parameters>
11317 <param id="data">
11318 <inbuf>
11319 <void/>
11320 <nullok>value is set to <code>NULL</code></nullok>
11321 </inbuf>
11322 <description>
11323 The value to be entered into the environment-local storage.
11324 </description>
11325 </param>
11326 </parameters>
11327 <errors>
11328 </errors>
11329 </function>
11330
11331 <function id="GetEnvironmentLocalStorage" jkernel="yes" phase="any" callbacksafe="safe" impl="innative notrace" num="147">
11332 <synopsis>Get Environment Local Storage</synopsis>
11333 <description>
11334 Called by the agent to get the value of the <jvmti/> environment-local
11335 storage.
11336 </description>
11337 <origin>new</origin>
11338 <capabilities>
11339 </capabilities>
11340 <parameters>
11341 <param id="data_ptr">
11342 <agentbuf><void/></agentbuf>
11343 <description>
11344 Pointer through which the value of the environment local
11345 storage is returned.
11346 If environment-local storage has not been set with
11347 <functionlink id="SetEnvironmentLocalStorage"></functionlink> returned
11348 pointer is <code>NULL</code>.
11349 </description>
11350 </param>
11351 </parameters>
11352 <errors>
11353 </errors>
11354 </function>
11355
11356 <function id="GetVersionNumber" jkernel="yes" phase="any" num="88">
11357 <synopsis>Get Version Number</synopsis>
11358 <description>
11359 Return the <jvmti/> version via <code>version_ptr</code>.
11360 The return value is the version identifier.
11361 The version identifier includes major, minor and micro
11362 version as well as the interface type.
11363 <constants id="jvmtiVersionInterfaceTypes" label="Version Interface Types" kind="bits">
11364 <constant id="JVMTI_VERSION_INTERFACE_JNI" num="0x00000000">
11365 Value of <code>JVMTI_VERSION_MASK_INTERFACE_TYPE</code> for JNI.
11366 </constant>
11367 <constant id="JVMTI_VERSION_INTERFACE_JVMTI" num="0x30000000">
11368 Value of <code>JVMTI_VERSION_MASK_INTERFACE_TYPE</code> for <jvmti/>.
11369 </constant>
11370 </constants>
11371 <constants id="jvmtiVersionMasks" label="Version Masks" kind="bits">
11372 <constant id="JVMTI_VERSION_MASK_INTERFACE_TYPE" num="0x70000000">
11373 Mask to extract interface type.
11374 The value of the version returned by this function masked with
11375 <code>JVMTI_VERSION_MASK_INTERFACE_TYPE</code> is always
11376 <code>JVMTI_VERSION_INTERFACE_JVMTI</code>
11377 since this is a <jvmti/> function.
11378 </constant>
11379 <constant id="JVMTI_VERSION_MASK_MAJOR" num="0x0FFF0000">
11380 Mask to extract major version number.
11381 </constant>
11382 <constant id="JVMTI_VERSION_MASK_MINOR" num="0x0000FF00">
11383 Mask to extract minor version number.
11384 </constant>
11385 <constant id="JVMTI_VERSION_MASK_MICRO" num="0x000000FF">
11386 Mask to extract micro version number.
11387 </constant>
11388 </constants>
11389 <constants id="jvmtiVersionShifts" label="Version Shifts" kind="bits">
11390 <constant id="JVMTI_VERSION_SHIFT_MAJOR" num="16">
11391 Shift to extract major version number.
11392 </constant>
11393 <constant id="JVMTI_VERSION_SHIFT_MINOR" num="8">
11394 Shift to extract minor version number.
11395 </constant>
11396 <constant id="JVMTI_VERSION_SHIFT_MICRO" num="0">
11397 Shift to extract micro version number.
11398 </constant>
11399 </constants>
11400 </description>
11401 <origin>jvmdi</origin>
11402 <capabilities>
11403 </capabilities>
11404 <parameters>
11405 <param id="version_ptr">
11406 <outptr><jint/></outptr>
11407 <description>
11408 On return, points to the <jvmti/> version.
11409 </description>
11410 </param>
11411 </parameters>
11412 <errors>
11413 </errors>
11414 </function>
11415
11416
11417 <function id="GetErrorName" phase="any" num="128">
11418 <synopsis>Get Error Name</synopsis>
11419 <description>
11420 Return the symbolic name for an
11421 <internallink id="ErrorSection">error code</internallink>.
11422 <p/>
11423 For example
11424 <code>GetErrorName(env, JVMTI_ERROR_NONE, &err_name)</code>
11425 would return in <code>err_name</code> the string
11426 <code>"JVMTI_ERROR_NONE"</code>.
11427 </description>
11428 <origin>new</origin>
11429 <capabilities>
11430 </capabilities>
11431 <parameters>
11432 <param id="error">
11433 <enum>jvmtiError</enum>
11434 <description>
11435 The error code.
11436 </description>
11437 </param>
11438 <param id="name_ptr">
11439 <allocbuf><char/></allocbuf>
11440 <description>
11441 On return, points to the error name.
11442 The name is encoded as a
11443 <internallink id="mUTF">modified UTF-8</internallink> string,
11444 but is restricted to the ASCII subset.
11445 </description>
11446 </param>
11447 </parameters>
11448 <errors>
11449 </errors>
11450 </function>
11451
11452 <function id="SetVerboseFlag" phase="any" num="150">
11453 <synopsis>Set Verbose Flag</synopsis>
11454 <description>
11455 <constants id="jvmtiVerboseFlag" label="Verbose Flag Enumeration" kind="enum">
11456 <constant id="JVMTI_VERBOSE_OTHER" num="0">
11457 Verbose output other than the below.
11458 </constant>
11459 <constant id="JVMTI_VERBOSE_GC" num="1">
11460 Verbose garbage collector output, like that specified with <code>-verbose:gc</code>.
11461 </constant>
11462 <constant id="JVMTI_VERBOSE_CLASS" num="2">
11463 Verbose class loading output, like that specified with <code>-verbose:class</code>.
11464 </constant>
11465 <constant id="JVMTI_VERBOSE_JNI" num="4">
11466 Verbose JNI output, like that specified with <code>-verbose:jni</code>.
11467 </constant>
11468 </constants>
11469 Control verbose output.
11470 This is the output which typically is sent to <code>stderr</code>.
11471 </description>
11472 <origin>new</origin>
11473 <capabilities>
11474 </capabilities>
11475 <parameters>
11476 <param id="flag">
11477 <enum>jvmtiVerboseFlag</enum>
11478 <description>
11479 Which verbose flag to set.
11480 </description>
11481 </param>
11482 <param id="value">
11483 <jboolean/>
11484 <description>
11485 New value of the flag.
11486 </description>
11487 </param>
11488 </parameters>
11489 <errors>
11490 </errors>
11491 </function>
11492
11493
11494 <function id="GetJLocationFormat" phase="any" num="129">
11495 <synopsis>Get JLocation Format</synopsis>
11496 <description>
11497 Although the greatest functionality is achieved with location information
11498 referencing the virtual machine bytecode index, the definition of
11499 <code>jlocation</code> has intentionally been left unconstrained to allow VM
11500 implementations that do not have this information.
11501 <p/>
11502 This function describes the representation of <code>jlocation</code> used in this VM.
11503 If the returned format is <datalink id="JVMTI_JLOCATION_JVMBCI"></datalink>,
11504 <code>jlocation</code>s can
11505 be used as in indices into the array returned by
11506 <functionlink id="GetBytecodes"></functionlink>.
11507 <constants id="jvmtiJlocationFormat" label="JLocation Format Enumeration" kind="enum">
11508 <constant id="JVMTI_JLOCATION_JVMBCI" num="1">
11509 <code>jlocation</code> values represent virtual machine
11510 bytecode indices--that is, offsets into the
11511 virtual machine code for a method.
11512 </constant>
11513 <constant id="JVMTI_JLOCATION_MACHINEPC" num="2">
11514 <code>jlocation</code> values represent native machine
11515 program counter values.
11516 </constant>
11517 <constant id="JVMTI_JLOCATION_OTHER" num="0">
11518 <code>jlocation</code> values have some other representation.
11519 </constant>
11520 </constants>
11521 </description>
11522 <origin>new</origin>
11523 <capabilities>
11524 </capabilities>
11525 <parameters>
11526 <param id="format_ptr">
11527 <outptr><enum>jvmtiJlocationFormat</enum></outptr>
11528 <description>
11529 On return, points to the format identifier for <code>jlocation</code> values.
11530 </description>
11531 </param>
11532 </parameters>
11533 <errors>
11534 </errors>
11535 </function>
11536
11537 </category>
11538
11539 <category id="heap_monitoring" label="Heap Monitoring">
11540 <typedef id="jvmtiStackTrace" label="Stack Trace">
11541 <field id="frames">
11542 <allocfieldbuf outcount="frame_count">
11543 <struct>jvmtiFrameInfo</struct>
11544 </allocfieldbuf>
11545 <description>Pointer to the call frames.</description>
11546 </field>
11547 <field id="frame_count">
11548 <jint/>
11549 <description>The number of frames for the trace.</description>
11550 </field>
11551 <field id="size">
11552 <jint/>
11553 <description>The size of the object allocation.</description>
11554 </field>
11555 <field id="thread_id">
11556 <jlong/>
11557 <description>The thread id number.</description>
11558 </field>
11559 </typedef>
11560
11561 <typedef id="jvmtiStackTraces" label="Stack Traces">
11562 <field id="stack_traces">
11563 <allocfieldbuf outcount="trace_count">
11564 <struct>jvmtiStackTrace</struct>
11565 </allocfieldbuf>
11566 <description>
11567 The <datalink id="jvmtiStackTrace"/> array with the various stack traces.
11568 </description>
11569 </field>
11570
11571 <field id="trace_count">
11572 <jint/>
11573 <description>
11574 Number of traces pointed by the array <datalink id="jvmtiStackTraces"/>.
11575 </description>
11576 </field>
11577 </typedef>
11578
11579 <typedef id="jvmtiHeapSamplingStats" label="Heap Sampling Statistics">
11580 <field id="sample_count">
11581 <jlong/>
11582 <description>
11583 The number of sampled allocations during the lifetime of the sampler.
11584 For very long sampling, this number can overflow.
11585 </description>
11586 </field>
11587
11588 <field id="garbage_collected_samples">
11589 <jlong/>
11590 <description>
11591 The number of samples already garbage collected.
11592 For very long sampling, this number can overflow.
11593 </description>
11594 </field>
11595
11596 <field id="sample_rate_accumulation">
11597 <jlong/>
11598 <description>
11599 Accumulation of the sample rates chosen.
11600 For very long sampling, this number can overflow.
11601 </description>
11602 </field>
11603
11604 <field id="sample_rate_count">
11605 <jlong/>
11606 <description>
11607 The number of sample rates chosen.
11608 For very long sampling, this number can overflow.
11609 </description>
11610 </field>
11611
11612 <field id="stack_depth_accumulation">
11613 <jlong/>
11614 <description>
11615 Accumulation of stack depths collected by the sampler.
11616 For very long sampling, this number can overflow.
11617 </description>
11618 </field>
11619 </typedef>
11620
11621 <function id="StartHeapSampling" phase="any" num="156">
11622 <synopsis>Start Heap Sampling</synopsis>
11623 <description>
11624 Start the heap sampler in the JVM. The function provides, via its argument, the sampling
11625 rate requested and will fill internal data structures with heap allocation samples. The
11626 samples are obtained via the <functionlink id="GetLiveTraces"></functionlink>,
11627 <functionlink id="GetGarbageTraces"></functionlink>, <functionlink id="GetFrequentGarbageTraces"></functionlink>,
11628 functions.
11629
11630 Starting the heap sampler resets internal traces and counters. Therefore stopping the sampler
11631 puts internal trace samples and counters on pause for post-processing.
11632 </description>
11633 <origin>new</origin>
11634 <capabilities>
11635 <required id="can_sample_heap"></required>
11636 </capabilities>
11637 <parameters>
11638 <param id="monitoring_rate">
11639 <jint/>
11640 <description>
11641 The monitoring rate used for sampling. The sampler will use a statistical approach to
11642 provide in average sampling every <paramlink id="monitoring_rate"/> allocated bytes.
11643
11644 Note: a low monitoring rate will incur a higher overhead, therefore, the sampler should
11645 only be used when knowing it may impact performance.
11646 </description>
11647 </param>
11648 <param id="max_gc_storage">
11649 <jint/>
11650 <description>
11651 The maximum storage used for the GC samples in the sampler. By default, the value is 200.
11652 </description>
11653 </param>
11654 </parameters>
11655 <errors>
11656 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
11657 <paramlink id="monitoring_period"></paramlink> is less than zero.
11658 </error>
11659 </errors>
11660 </function>
11661
11662 <function id="StopHeapSampling" phase="any" num="157">
11663 <synopsis>Stop Heap Sampling</synopsis>
11664 <description>
11665 Stop the heap sampler in the JVM.
11666 Any sample obtained during sampling is still available via the <functionlink id="GetLiveTraces"></functionlink>,
11667 <functionlink id="GetGarbageTraces"></functionlink>, <functionlink id="GetFrequentGarbageTraces"></functionlink>,
11668 functions.
11669
11670 Starting the heap sampler resets internal traces and counters. Therefore stopping the sampler
11671 puts internal trace samples and counters on pause for post-processing.
11672 </description>
11673 <origin>new</origin>
11674 <capabilities>
11675 <required id="can_sample_heap"></required>
11676 </capabilities>
11677 <parameters>
11678 </parameters>
11679 <errors>
11680 </errors>
11681 </function>
11682
11683 <function id="GetLiveTraces" num="158">
11684 <synopsis>Get Live Traces</synopsis>
11685 <description>
11686 Get Live Heap Sampled traces. The fields of the <datalink id="jvmtiStackTraces"/>
11687 structure are filled in with details of the specified sampled allocation.
11688
11689 This method can be called at any time but if the sampler has not been started via at least
11690 one call to <functionlink id="StartHeapSampling"></functionlink> it returns no traces.
11691 </description>
11692 <origin>new</origin>
11693 <capabilities>
11694 <required id="can_sample_heap"></required>
11695 </capabilities>
11696 <parameters>
11697 <param id="stack_traces">
11698 <outptr><struct>jvmtiStackTraces</struct></outptr>
11699 <description>
11700 The stack trace data structure to be filled.
11701 </description>
11702 </param>
11703 </parameters>
11704 <errors>
11705 </errors>
11706 </function>
11707
11708 <function id="GetGarbageTraces" num="159">
11709 <synopsis>Get Garbage Traces</synopsis>
11710 <description>
11711 Get the recent garbage heap sampled traces. The fields of the <datalink id="jvmtiStackTraces"/>
11712 structure are filled in with details of the specified sampled allocation.
11713
11714 This method can be called at any time but if the sampler has not been started via at least
11715 one call to <functionlink id="StartHeapSampling"></functionlink> it returns no traces.
11716 </description>
11717 <origin>new</origin>
11718 <capabilities>
11719 <required id="can_sample_heap"></required>
11720 </capabilities>
11721 <parameters>
11722 <param id="stack_traces">
11723 <outptr><struct>jvmtiStackTraces</struct></outptr>
11724 <description>
11725 The stack trace data structure to be filled.
11726 </description>
11727 </param>
11728 </parameters>
11729 <errors>
11730 </errors>
11731 </function>
11732
11733 <function id="GetFrequentGarbageTraces" num="160">
11734 <synopsis>Get Frequent Garbage Traces</synopsis>
11735 <description>
11736 Get the frequent garbage heap sampled traces. The fields of the <datalink id="jvmtiStackTraces"/>
11737 structure are filled in with details of the specified sampled allocation.
11738
11739 This method can be called at any time but if the sampler has not been started via at least
11740 one call to <functionlink id="StartHeapSampling"></functionlink> it returns no traces.
11741 </description>
11742 <origin>new</origin>
11743 <capabilities>
11744 <required id="can_sample_heap"></required>
11745 </capabilities>
11746 <parameters>
11747 <param id="stack_traces">
11748 <outptr><struct>jvmtiStackTraces</struct></outptr>
11749 <description>
11750 The stack trace data structure to be filled.
11751 </description>
11752 </param>
11753 </parameters>
11754 <errors>
11755 </errors>
11756 </function>
11757
11758 <function id="ReleaseTraces" num="161">
11759 <synopsis>Release traces provided by the heap monitoring</synopsis>
11760 <description>
11761 Release traces provided by any of the trace retrieval methods.
11762 </description>
11763 <origin>new</origin>
11764 <capabilities>
11765 <required id="can_sample_heap"></required>
11766 </capabilities>
11767 <parameters>
11768 <param id="stack_traces">
11769 <outptr><struct>jvmtiStackTraces</struct></outptr>
11770 <description>
11771 The stack trace data structure to be released.
11772 </description>
11773 </param>
11774 </parameters>
11775 <errors>
11776 </errors>
11777 </function>
11778
11779 <function id="GetHeapSamplingStats" num="162">
11780 <synopsis>Get the heap sampling statistics</synopsis>
11781 <description>
11782 Returns a <datalink id="jvmtiHeapSamplingStats"/> to understand the heap sampling behavior and current
11783 internal data storage status.
11784
11785 This method can be called at any time but if the sampler has not been started via at least
11786 one call to <functionlink id="StartHeapSampling"></functionlink> it returns a zeroed-out structure.
11787 </description>
11788 <origin>new</origin>
11789 <capabilities>
11790 <required id="can_sample_heap"></required>
11791 </capabilities>
11792 <parameters>
11793 <param id="stats">
11794 <outptr><struct>jvmtiHeapSamplingStats</struct></outptr>
11795 <description>
11796 The structure to be filled with the heap sampler's statistics.
11797 </description>
11798 </param>
11799 </parameters>
11800 <errors>
11801 </errors>
11802 </function>
11803 </category>
11804
11805 </functionsection>
11806
11807 <errorsection label="Error Reference">
11808 <intro>
11809 Every <jvmti/> function returns a <b><code>jvmtiError</code></b> error code.
11810 <p/>
11811 It is the responsibility of the agent to call <jvmti/> functions with
11812 valid parameters and in the proper context (calling thread is attached,
11813 phase is correct, etc.).
11814 Detecting some error conditions may be difficult, inefficient, or
11815 impossible for an implementation.
11816 The errors listed in
11817 <internallink id="reqerrors">Function Specific Required Errors</internallink>
11818 must be detected by the implementation.
11819 All other errors represent the recommended response to the error
11820 condition.
11821 </intro>
11822
11823 <errorcategory id="universal-error" label="Universal Errors">
11824 <intro>
11825 The following errors may be returned by any function
11826 </intro>
11827
11828 <errorid id="JVMTI_ERROR_NONE" num="0">
11829 No error has occurred. This is the error code that is returned
11830 on successful completion of the function.
11831 </errorid>
11832 <errorid id="JVMTI_ERROR_NULL_POINTER" num="100">
11833 Pointer is unexpectedly <code>NULL</code>.
11834 </errorid>
11835 <errorid id="JVMTI_ERROR_OUT_OF_MEMORY" num="110">
11836 The function attempted to allocate memory and no more memory was
11837 available for allocation.
11838 </errorid>
11839 <errorid id="JVMTI_ERROR_ACCESS_DENIED" num="111">
11840 The desired functionality has not been enabled in this virtual machine.
11841 </errorid>
11842 <errorid id="JVMTI_ERROR_UNATTACHED_THREAD" num="115">
11843 The thread being used to call this function is not attached
11844 to the virtual machine. Calls must be made from attached threads.
11845 See <code>AttachCurrentThread</code> in the JNI invocation API.
11846 </errorid>
11847 <errorid id="JVMTI_ERROR_INVALID_ENVIRONMENT" num="116">
11848 The <jvmti/> environment provided is no longer connected or is
11849 not an environment.
11850 </errorid>
11851 <errorid id="JVMTI_ERROR_WRONG_PHASE" num="112">
11852 The desired functionality is not available in the current
11853 <functionlink id="GetPhase">phase</functionlink>.
11854 Always returned if the virtual machine has completed running.
11855 </errorid>
11856 <errorid id="JVMTI_ERROR_INTERNAL" num="113">
11857 An unexpected internal error has occurred.
11858 </errorid>
11859 </errorcategory>
11860
11861 <errorcategory id="reqerrors" label="Function Specific Required Errors">
11862 <intro>
11863 The following errors are returned by some <jvmti/> functions and must
11864 be returned by the implementation when the condition occurs.
11865 </intro>
11866
11867 <errorid id="JVMTI_ERROR_INVALID_PRIORITY" num="12">
11868 Invalid priority.
11869 </errorid>
11870 <errorid id="JVMTI_ERROR_THREAD_NOT_SUSPENDED" num="13">
11871 Thread was not suspended.
11872 </errorid>
11873 <errorid id="JVMTI_ERROR_THREAD_SUSPENDED" num="14">
11874 Thread already suspended.
11875 </errorid>
11876 <errorid id="JVMTI_ERROR_THREAD_NOT_ALIVE" num="15">
11877 This operation requires the thread to be alive--that is,
11878 it must be started and not yet have died.
11879 </errorid>
11880 <errorid id="JVMTI_ERROR_CLASS_NOT_PREPARED" num="22">
11881 The class has been loaded but not yet prepared.
11882 </errorid>
11883 <errorid id="JVMTI_ERROR_NO_MORE_FRAMES" num="31">
11884 There are no Java programming language or JNI stack frames at the specified depth.
11885 </errorid>
11886 <errorid id="JVMTI_ERROR_OPAQUE_FRAME" num="32">
11887 Information about the frame is not available (e.g. for native frames).
11888 </errorid>
11889 <errorid id="JVMTI_ERROR_DUPLICATE" num="40">
11890 Item already set.
11891 </errorid>
11892 <errorid id="JVMTI_ERROR_NOT_FOUND" num="41">
11893 Desired element (e.g. field or breakpoint) not found
11894 </errorid>
11895 <errorid id="JVMTI_ERROR_NOT_MONITOR_OWNER" num="51">
11896 This thread doesn't own the raw monitor.
11897 </errorid>
11898 <errorid id="JVMTI_ERROR_INTERRUPT" num="52">
11899 The call has been interrupted before completion.
11900 </errorid>
11901 <errorid id="JVMTI_ERROR_UNMODIFIABLE_CLASS" num="79">
11902 The class cannot be modified.
11903 </errorid>
11904 <errorid id="JVMTI_ERROR_UNMODIFIABLE_MODULE" num="80">
11905 The module cannot be modified.
11906 </errorid>
11907 <errorid id="JVMTI_ERROR_NOT_AVAILABLE" num="98">
11908 The functionality is not available in this virtual machine.
11909 </errorid>
11910 <errorid id="JVMTI_ERROR_ABSENT_INFORMATION" num="101">
11911 The requested information is not available.
11912 </errorid>
11913 <errorid id="JVMTI_ERROR_INVALID_EVENT_TYPE" num="102">
11914 The specified event type ID is not recognized.
11915 </errorid>
11916 <errorid id="JVMTI_ERROR_NATIVE_METHOD" num="104">
11917 The requested information is not available for native method.
11918 </errorid>
11919 <errorid id="JVMTI_ERROR_CLASS_LOADER_UNSUPPORTED" num="106">
11920 The class loader does not support this operation.
11921 </errorid>
11922 </errorcategory>
11923
11924 <errorcategory id="function-specific-errors" label="Function Specific Agent Errors">
11925 <intro>
11926 The following errors are returned by some <jvmti/> functions.
11927 They are returned in the event of invalid parameters passed by the
11928 agent or usage in an invalid context.
11929 An implementation is not required to detect these errors.
11930 </intro>
11931
11932 <errorid id="JVMTI_ERROR_INVALID_THREAD" num="10">
11933 The passed thread is not a valid thread.
11934 </errorid>
11935 <errorid id="JVMTI_ERROR_INVALID_FIELDID" num="25">
11936 Invalid field.
11937 </errorid>
11938 <errorid id="JVMTI_ERROR_INVALID_MODULE" num="26">
11939 Invalid module.
11940 </errorid>
11941 <errorid id="JVMTI_ERROR_INVALID_METHODID" num="23">
11942 Invalid method.
11943 </errorid>
11944 <errorid id="JVMTI_ERROR_INVALID_LOCATION" num="24">
11945 Invalid location.
11946 </errorid>
11947 <errorid id="JVMTI_ERROR_INVALID_OBJECT" num="20">
11948 Invalid object.
11949 </errorid>
11950 <errorid id="JVMTI_ERROR_INVALID_CLASS" num="21">
11951 Invalid class.
11952 </errorid>
11953 <errorid id="JVMTI_ERROR_TYPE_MISMATCH" num="34">
11954 The variable is not an appropriate type for the function used.
11955 </errorid>
11956 <errorid id="JVMTI_ERROR_INVALID_SLOT" num="35">
11957 Invalid slot.
11958 </errorid>
11959 <errorid id="JVMTI_ERROR_MUST_POSSESS_CAPABILITY" num="99">
11960 The capability being used is false in this environment.
11961 </errorid>
11962 <errorid id="JVMTI_ERROR_INVALID_THREAD_GROUP" num="11">
11963 Thread group invalid.
11964 </errorid>
11965 <errorid id="JVMTI_ERROR_INVALID_MONITOR" num="50">
11966 Invalid raw monitor.
11967 </errorid>
11968 <errorid id="JVMTI_ERROR_ILLEGAL_ARGUMENT" num="103">
11969 Illegal argument.
11970 </errorid>
11971 <errorid id="JVMTI_ERROR_INVALID_TYPESTATE" num="65">
11972 The state of the thread has been modified, and is now inconsistent.
11973 </errorid>
11974 <errorid id="JVMTI_ERROR_UNSUPPORTED_VERSION" num="68">
11975 A new class file has a version number not supported by this VM.
11976 </errorid>
11977 <errorid id="JVMTI_ERROR_INVALID_CLASS_FORMAT" num="60">
11978 A new class file is malformed (the VM would return a <code>ClassFormatError</code>).
11979 </errorid>
11980 <errorid id="JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION" num="61">
11981 The new class file definitions would lead to a circular
11982 definition (the VM would return a <code>ClassCircularityError</code>).
11983 </errorid>
11984 <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED" num="63">
11985 A new class file would require adding a method.
11986 </errorid>
11987 <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED" num="64">
11988 A new class version changes a field.
11989 </errorid>
11990 <errorid id="JVMTI_ERROR_FAILS_VERIFICATION" num="62">
11991 The class bytes fail verification.
11992 </errorid>
11993 <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED" num="66">
11994 A direct superclass is different for the new class
11995 version, or the set of directly implemented
11996 interfaces is different.
11997 </errorid>
11998 <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED" num="67">
11999 A new class version does not declare a method
12000 declared in the old class version.
12001 </errorid>
12002 <errorid id="JVMTI_ERROR_NAMES_DONT_MATCH" num="69">
12003 The class name defined in the new class file is
12004 different from the name in the old class object.
12005 </errorid>
12006 <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED" num="70">
12007 A new class version has different modifiers.
12008 </errorid>
12009 <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED" num="71">
12010 A method in the new class version has different modifiers
12011 than its counterpart in the old class version.
12012 </errorid>
12013 </errorcategory>
12014 </errorsection>
12015
12016 <eventsection label="Events">
12017 <intro label="Handling Events" id="eventIntro">
12018 Agents can be informed of many events that occur in application
12019 programs.
12020 <p/>
12021 To handle events, designate a set of callback functions with
12022 <functionlink id="SetEventCallbacks"></functionlink>.
12023 For each event the corresponding callback function will be
12024 called.
12025 Arguments to the callback function provide additional
12026 information about the event.
12027 <p/>
12028 The callback function is usually called from within an application
12029 thread. The <jvmti/> implementation does not
12030 queue events in any way. This means
12031 that event callback functions must be written
12032 carefully. Here are some general guidelines. See
12033 the individual event descriptions for further
12034 suggestions.
12035 <p/>
12036 <ul>
12037 <li>Any exception thrown during the execution of an event callback can
12038 overwrite any current pending exception in the current application thread.
12039 Care must be taken to preserve a pending exception
12040 when an event callback makes a JNI call that might generate an exception.
12041 </li>
12042 <li>Event callback functions must be re-entrant. The <jvmti/> implementation does
12043 not queue events. If an agent needs to process events one at a time, it
12044 can use a raw monitor inside the
12045 event callback functions to serialize event processing.
12046 </li>
12047 <li>Event callback functions that execute JNI's FindClass function to load
12048 classes need to note that FindClass locates the class loader associated
12049 with the current native method. For the purposes of class loading, an
12050 event callback that includes a JNI environment as a parameter to the
12051 callback will treated as if it is a native call, where the native method
12052 is in the class of the event thread's current frame.
12053 </li>
12054 </ul>
12055 <p/>
12056 Some <jvmti/> events identify objects with JNI references.
12057 All references
12058 in <jvmti/> events are JNI local references and will become invalid
12059 after the event callback returns.
12060 Unless stated otherwise, memory referenced by pointers sent in event
12061 callbacks may not be referenced after the event callback returns.
12062 <p/>
12063 Except where stated otherwise, events are delivered on the thread
12064 that caused the event.
12065 Events are sent at the time they occur.
12066 The specification for each event includes the set of
12067 <functionlink id="GetPhase">phases</functionlink> in which it can be sent;
12068 if an event triggering activity occurs during another phase, no event
12069 is sent.
12070 <p/>
12071 A thread that generates an event does not change its execution status
12072 (for example, the event does not cause the thread to be suspended).
12073 If an agent wishes the event to result in suspension, then the agent
12074 is responsible for explicitly suspending the thread with
12075 <functionlink id="SuspendThread"></functionlink>.
12076 <p/>
12077 If an event is enabled in multiple environments, the event will be sent
12078 to each agent in the order that the environments were created.
12079 </intro>
12080
12081 <intro label="Enabling Events" id="enablingevents">
12082 All events are initially disabled. In order to receive any
12083 event:
12084 <ul>
12085 <li>
12086 If the event requires a capability, that capability must
12087 be added with
12088 <functionlink id="AddCapabilities"></functionlink>.
12089 </li>
12090 <li>
12091 A callback for the event must be set with
12092 <functionlink id="SetEventCallbacks"></functionlink>.
12093 </li>
12094 <li>
12095 The event must be enabled with
12096 <functionlink id="SetEventNotificationMode"></functionlink>.
12097 </li>
12098 </ul>
12099 </intro>
12100
12101 <intro label="Multiple Co-located Events" id="eventorder">
12102 In many situations it is possible for multiple events to occur
12103 at the same location in one thread. When this happens, all the events
12104 are reported through the event callbacks in the order specified in this section.
12105 <p/>
12106 If the current location is at the entry point of a method, the
12107 <eventlink id="MethodEntry"></eventlink> event is reported before
12108 any other event at the current location in the same thread.
12109 <p/>
12110 If an exception catch has been detected at the current location,
12111 either because it is the beginning of a catch clause or a native method
12112 that cleared a pending exception has returned, the
12113 <code>exceptionCatch</code> event is reported before
12114 any other event at the current location in the same thread.
12115 <p/>
12116 If a <code>singleStep</code> event or
12117 <code>breakpoint</code> event is triggered at the
12118 current location, the event is defined to occur
12119 immediately before the code at the current location is executed.
12120 These events are reported before any events which are triggered
12121 by the execution of code at the current location in the same
12122 thread (specifically:
12123 <code>exception</code>,
12124 <code>fieldAccess</code>, and
12125 <code>fieldModification</code>).
12126 If both a step and breakpoint event are triggered for the same thread and
12127 location, the step event is reported before the breakpoint event.
12128 <p/>
12129 If the current location is the exit point of a method (that is, the last
12130 location before returning to the caller), the
12131 <eventlink id="MethodExit"></eventlink> event and
12132 the <eventlink id="FramePop"></eventlink> event (if requested)
12133 are reported after all other events at the current location in the same
12134 thread. There is no specified ordering of these two events
12135 with respect to each other.
12136 <p/>
12137 Co-located events can be triggered during the processing of some other
12138 event by the agent at the same location in the same thread.
12139 If such an event, of type <i>y</i>, is triggered during the processing of
12140 an event of type <i>x</i>, and if <i>x</i>
12141 precedes <i>y</i> in the ordering specified above, the co-located event
12142 <i>y</i> is reported for the current thread and location. If <i>x</i> does not precede
12143 <i>y</i>, <i>y</i> is not reported for the current thread and location.
12144 For example, if a breakpoint is set at the current location
12145 during the processing of <eventlink id="SingleStep"></eventlink>,
12146 that breakpoint will be reported before the thread moves off the current
12147 location.
12148 <p/>The following events are never considered to be co-located with
12149 other events.
12150 <ul>
12151 <li><eventlink id="VMStart"></eventlink></li>
12152 <li><eventlink id="VMInit"></eventlink></li>
12153 <li><eventlink id="VMDeath"></eventlink></li>
12154 <li><eventlink id="ThreadStart"></eventlink></li>
12155 <li><eventlink id="ThreadEnd"></eventlink></li>
12156 <li><eventlink id="ClassLoad"></eventlink></li>
12157 <li><eventlink id="ClassPrepare"></eventlink></li>
12158 </ul>
12159 </intro>
12160
12161 <intro label="Event Callbacks" id="jvmtiEventCallbacks">
12162 The event callback structure below is used to specify the handler function
12163 for events. It is set with the
12164 <functionlink id="SetEventCallbacks"></functionlink> function.
12165 </intro>
12166
12167 <event label="Single Step"
12168 id="SingleStep" const="JVMTI_EVENT_SINGLE_STEP" filtered="thread" num="60">
12169 <description>
12170 Single step events allow the agent to trace thread execution
12171 at the finest granularity allowed by the VM. A single step event is
12172 generated whenever a thread reaches a new location.
12173 Typically, single step events represent the completion of one VM
12174 instruction as defined in <vmspec/>. However, some implementations
12175 may define locations differently. In any case the
12176 <code>method</code> and <code>location</code>
12177 parameters uniquely identify the current location and allow
12178 the mapping to source file and line number when that information is
12179 available.
12180 <p/>
12181 No single step events are generated from within native methods.
12182 </description>
12183 <origin>jvmdi</origin>
12184 <capabilities>
12185 <required id="can_generate_single_step_events"></required>
12186 </capabilities>
12187 <parameters>
12188 <param id="jni_env">
12189 <outptr>
12190 <struct>JNIEnv</struct>
12191 </outptr>
12192 <description>
12193 The JNI environment of the event (current) thread
12194 </description>
12195 </param>
12196 <param id="thread">
12197 <jthread/>
12198 <description>
12199 Thread about to execution a new instruction
12200 </description>
12201 </param>
12202 <param id="klass">
12203 <jclass method="method"/>
12204 <description>
12205 Class of the method about to execute a new instruction
12206 </description>
12207 </param>
12208 <param id="method">
12209 <jmethodID class="klass"/>
12210 <description>
12211 Method about to execute a new instruction
12212 </description>
12213 </param>
12214 <param id="location">
12215 <jlocation/>
12216 <description>
12217 Location of the new instruction
12218 </description>
12219 </param>
12220 </parameters>
12221 </event>
12222
12223 <event label="Breakpoint"
12224 id="Breakpoint" const="JVMTI_EVENT_BREAKPOINT" filtered="thread" num="62">
12225 <description>
12226 Breakpoint events are generated whenever a thread reaches a location
12227 designated as a breakpoint with <functionlink id="SetBreakpoint"></functionlink>.
12228 The <code>method</code> and <code>location</code>
12229 parameters uniquely identify the current location and allow
12230 the mapping to source file and line number when that information is
12231 available.
12232 </description>
12233 <origin>jvmdi</origin>
12234 <capabilities>
12235 <required id="can_generate_breakpoint_events"></required>
12236 </capabilities>
12237 <parameters>
12238 <param id="jni_env">
12239 <outptr>
12240 <struct>JNIEnv</struct>
12241 </outptr>
12242 <description>
12243 The JNI environment of the event (current) thread.
12244 </description>
12245 </param>
12246 <param id="thread">
12247 <jthread/>
12248 <description>
12249 Thread that hit the breakpoint
12250 </description>
12251 </param>
12252 <param id="klass">
12253 <jclass method="method"/>
12254 <description>
12255 Class of the method that hit the breakpoint
12256 </description>
12257 </param>
12258 <param id="method">
12259 <jmethodID class="klass"/>
12260 <description>
12261 Method that hit the breakpoint
12262 </description>
12263 </param>
12264 <param id="location">
12265 <jlocation/>
12266 <description>
12267 location of the breakpoint
12268 </description>
12269 </param>
12270 </parameters>
12271 </event>
12272
12273 <event label="Field Access"
12274 id="FieldAccess" const="JVMTI_EVENT_FIELD_ACCESS" filtered="thread" num="63">
12275 <description>
12276 Field access events are generated whenever a thread accesses
12277 a field that was designated as a watchpoint
12278 with <functionlink id="SetFieldAccessWatch"></functionlink>.
12279 The <code>method</code> and <code>location</code>
12280 parameters uniquely identify the current location and allow
12281 the mapping to source file and line number when that information is
12282 available.
12283 </description>
12284 <origin>jvmdi</origin>
12285 <capabilities>
12286 <required id="can_generate_field_access_events"></required>
12287 </capabilities>
12288 <parameters>
12289 <param id="jni_env">
12290 <outptr>
12291 <struct>JNIEnv</struct>
12292 </outptr>
12293 <description>
12294 The JNI environment of the event (current) thread
12295 </description>
12296 </param>
12297 <param id="thread">
12298 <jthread/>
12299 <description>
12300 Thread accessing the field
12301 </description>
12302 </param>
12303 <param id="klass">
12304 <jclass method="method"/>
12305 <description>
12306 Class of the method where the access is occurring
12307 </description>
12308 </param>
12309 <param id="method">
12310 <jmethodID class="klass"/>
12311 <description>
12312 Method where the access is occurring
12313 </description>
12314 </param>
12315 <param id="location">
12316 <jlocation/>
12317 <description>
12318 Location where the access is occurring
12319 </description>
12320 </param>
12321 <param id="field_klass">
12322 <jclass field="field"/>
12323 <description>
12324 Class of the field being accessed
12325 </description>
12326 </param>
12327 <param id="object">
12328 <jobject/>
12329 <description>
12330 Object with the field being accessed if the field is an
12331 instance field; <code>NULL</code> otherwise
12332 </description>
12333 </param>
12334 <param id="field">
12335 <jfieldID class="field_klass"/>
12336 <description>
12337 Field being accessed
12338 </description>
12339 </param>
12340 </parameters>
12341 </event>
12342
12343 <event label="Field Modification"
12344 id="FieldModification" const="JVMTI_EVENT_FIELD_MODIFICATION" filtered="thread" num="64">
12345 <description>
12346 Field modification events are generated whenever a thread modifies
12347 a field that was designated as a watchpoint
12348 with <functionlink id="SetFieldModificationWatch"></functionlink>.
12349 The <code>method</code> and <code>location</code>
12350 parameters uniquely identify the current location and allow
12351 the mapping to source file and line number when that information is
12352 available.
12353 </description>
12354 <origin>jvmdi</origin>
12355 <capabilities>
12356 <required id="can_generate_field_modification_events"></required>
12357 </capabilities>
12358 <parameters>
12359 <param id="jni_env">
12360 <outptr>
12361 <struct>JNIEnv</struct>
12362 </outptr>
12363 <description>
12364 The JNI environment of the event (current) thread
12365 </description>
12366 </param>
12367 <param id="thread">
12368 <jthread/>
12369 <description>
12370 Thread modifying the field
12371 </description>
12372 </param>
12373 <param id="klass">
12374 <jclass method="method"/>
12375 <description>
12376 Class of the method where the modification is occurring
12377 </description>
12378 </param>
12379 <param id="method">
12380 <jmethodID class="klass"/>
12381 <description>
12382 Method where the modification is occurring
12383 </description>
12384 </param>
12385 <param id="location">
12386 <jlocation/>
12387 <description>
12388 Location where the modification is occurring
12389 </description>
12390 </param>
12391 <param id="field_klass">
12392 <jclass field="field"/>
12393 <description>
12394 Class of the field being modified
12395 </description>
12396 </param>
12397 <param id="object">
12398 <jobject/>
12399 <description>
12400 Object with the field being modified if the field is an
12401 instance field; <code>NULL</code> otherwise
12402 </description>
12403 </param>
12404 <param id="field">
12405 <jfieldID class="field_klass"/>
12406 <description>
12407 Field being modified
12408 </description>
12409 </param>
12410 <param id="signature_type">
12411 <char/>
12412 <description>
12413 Signature type of the new value
12414 </description>
12415 </param>
12416 <param id="new_value">
12417 <jvalue/>
12418 <description>
12419 The new value
12420 </description>
12421 </param>
12422 </parameters>
12423 </event>
12424
12425 <event label="Frame Pop"
12426 id="FramePop" const="JVMTI_EVENT_FRAME_POP" filtered="thread" num="61">
12427 <description>
12428 Frame pop events are generated upon exit from a single method
12429 in a single frame as specified
12430 in a call to <functionlink id="NotifyFramePop"></functionlink>.
12431 This is true whether termination is caused by
12432 executing its return instruction
12433 or by throwing an exception to its caller
12434 (see <paramlink id="was_popped_by_exception"></paramlink>).
12435 However, frame pops caused by the <functionlink id="PopFrame"/>
12436 function are not reported.
12437 <p/>
12438 The location reported by <functionlink id="GetFrameLocation"></functionlink>
12439 identifies the executable location in the returning method,
12440 immediately prior to the return.
12441 </description>
12442 <origin>jvmdi</origin>
12443 <capabilities>
12444 <required id="can_generate_frame_pop_events"></required>
12445 </capabilities>
12446 <parameters>
12447 <param id="jni_env">
12448 <outptr>
12449 <struct>JNIEnv</struct>
12450 </outptr>
12451 <description>
12452 The JNI environment of the event (current) thread
12453 </description>
12454 </param>
12455 <param id="thread">
12456 <jthread/>
12457 <description>
12458 Thread that is popping the frame
12459 </description>
12460 </param>
12461 <param id="klass">
12462 <jclass method="method"/>
12463 <description>
12464 Class of the method being popped
12465 </description>
12466 </param>
12467 <param id="method">
12468 <jmethodID class="klass"/>
12469 <description>
12470 Method being popped
12471 </description>
12472 </param>
12473 <param id="was_popped_by_exception">
12474 <jboolean/>
12475 <description>
12476 True if frame was popped by a thrown exception.
12477 False if method exited through its return instruction.
12478 </description>
12479 </param>
12480 </parameters>
12481 </event>
12482
12483 <event label="Method Entry"
12484 id="MethodEntry" const="JVMTI_EVENT_METHOD_ENTRY" filtered="thread" num="65">
12485 <description>
12486 Method entry events are generated upon entry of Java
12487 programming language methods (including native methods).
12488 <p/>
12489 The location reported by <functionlink id="GetFrameLocation"></functionlink>
12490 identifies the initial executable location in
12491 the method.
12492 <p/>
12493 Enabling method
12494 entry or exit events will significantly degrade performance on many platforms and is thus
12495 not advised for performance critical usage (such as profiling).
12496 <internallink id="bci">Bytecode instrumentation</internallink> should be
12497 used in these cases.
12498 </description>
12499 <origin>jvmdi</origin>
12500 <capabilities>
12501 <required id="can_generate_method_entry_events"></required>
12502 </capabilities>
12503 <parameters>
12504 <param id="jni_env">
12505 <outptr>
12506 <struct>JNIEnv</struct>
12507 </outptr>
12508 <description>
12509 The JNI environment of the event (current) thread
12510 </description>
12511 </param>
12512 <param id="thread">
12513 <jthread/>
12514 <description>
12515 Thread entering the method
12516 </description>
12517 </param>
12518 <param id="klass">
12519 <jclass method="method"/>
12520 <description>
12521 Class of the method being entered
12522 </description>
12523 </param>
12524 <param id="method">
12525 <jmethodID class="klass"/>
12526 <description>
12527 Method being entered
12528 </description>
12529 </param>
12530 </parameters>
12531 </event>
12532
12533 <event label="Method Exit"
12534 id="MethodExit" const="JVMTI_EVENT_METHOD_EXIT" filtered="thread" num="66">
12535 <description>
12536 Method exit events are generated upon exit from Java
12537 programming language methods (including native methods).
12538 This is true whether termination is caused by
12539 executing its return instruction
12540 or by throwing an exception to its caller
12541 (see <paramlink id="was_popped_by_exception"></paramlink>).
12542 <p/>
12543 The <code>method</code> field uniquely identifies the
12544 method being entered or exited. The <code>frame</code> field provides
12545 access to the stack frame for the method.
12546 <p/>
12547 The location reported by <functionlink id="GetFrameLocation"></functionlink>
12548 identifies the executable location in the returning method
12549 immediately prior to the return.
12550 <p/>
12551 Enabling method
12552 entry or exit events will significantly degrade performance on many platforms and is thus
12553 not advised for performance critical usage (such as profiling).
12554 <internallink id="bci">Bytecode instrumentation</internallink> should be
12555 used in these cases.
12556 </description>
12557 <origin>jvmdi</origin>
12558 <capabilities>
12559 <required id="can_generate_method_exit_events"></required>
12560 </capabilities>
12561 <parameters>
12562 <param id="jni_env">
12563 <outptr>
12564 <struct>JNIEnv</struct>
12565 </outptr>
12566 <description>
12567 The JNI environment of the event (current) thread
12568 </description>
12569 </param>
12570 <param id="thread">
12571 <jthread/>
12572 <description>
12573 Thread exiting the method
12574 </description>
12575 </param>
12576 <param id="klass">
12577 <jclass method="method"/>
12578 <description>
12579 Class of the method being exited
12580 </description>
12581 </param>
12582 <param id="method">
12583 <jmethodID class="klass"/>
12584 <description>
12585 Method being exited
12586 </description>
12587 </param>
12588 <param id="was_popped_by_exception">
12589 <jboolean/>
12590 <description>
12591 True if frame was popped by a thrown exception.
12592 False if method exited through its return instruction.
12593 </description>
12594 </param>
12595 <param id="return_value">
12596 <jvalue/>
12597 <description>
12598 The return value of the method being exited.
12599 Undefined and should not be used if
12600 <paramlink id="was_popped_by_exception"></paramlink>
12601 is true.
12602 </description>
12603 </param>
12604 </parameters>
12605 </event>
12606
12607 <event label="Native Method Bind" phase="any"
12608 id="NativeMethodBind" const="JVMTI_EVENT_NATIVE_METHOD_BIND" num="67">
12609 <description>
12610 A Native Method Bind event is sent when a VM binds a
12611 Java programming language native method
12612 to the address of a function that implements the native method.
12613 This will occur when the native method is called for the first time
12614 and also occurs when the JNI function <code>RegisterNatives</code> is called.
12615 This event allows the bind to be redirected to an agent-specified
12616 proxy function.
12617 This event is not sent when the native method is unbound.
12618 Typically, this proxy function will need to be specific to a
12619 particular method or, to handle the general case, automatically
12620 generated assembly code, since after instrumentation code is
12621 executed the function at the original binding
12622 address will usually be invoked.
12623 The original binding can be restored or the redirection changed
12624 by use of the JNI function <code>RegisterNatives</code>.
12625 Some events may be sent during the primordial phase, JNI and
12626 most of <jvmti/> cannot be used at this time but the method and
12627 address can be saved for use later.
12628 </description>
12629 <origin>new</origin>
12630 <capabilities>
12631 <required id="can_generate_native_method_bind_events"></required>
12632 </capabilities>
12633 <parameters>
12634 <param id="jni_env">
12635 <outptr>
12636 <struct>JNIEnv</struct>
12637 </outptr>
12638 <description>
12639 The JNI environment of the event (current) thread
12640 Will be <code>NULL</code> if sent during the primordial
12641 <functionlink id="GetPhase">phase</functionlink>.
12642 </description>
12643 </param>
12644 <param id="thread">
12645 <jthread/>
12646 <description>
12647 Thread requesting the bind
12648 </description>
12649 </param>
12650 <param id="klass">
12651 <jclass method="method"/>
12652 <description>
12653 Class of the method being bound
12654 </description>
12655 </param>
12656 <param id="method">
12657 <jmethodID class="klass"/>
12658 <description>
12659 Native method being bound
12660 </description>
12661 </param>
12662 <param id="address">
12663 <outptr><void/></outptr>
12664 <description>
12665 The address the VM is about to bind to--that is, the
12666 address of the implementation of the native method
12667 </description>
12668 </param>
12669 <param id="new_address_ptr">
12670 <agentbuf><void/></agentbuf>
12671 <description>
12672 if the referenced address is changed (that is, if
12673 <code>*new_address_ptr</code> is set), the binding
12674 will instead be made to the supplied address.
12675 </description>
12676 </param>
12677 </parameters>
12678 </event>
12679
12680 <event label="Exception"
12681 id="Exception" const="JVMTI_EVENT_EXCEPTION" filtered="thread" num="58">
12682 <description>
12683 Exception events are generated whenever an exception is first detected
12684 in a Java programming language method.
12685 Where "exception" means any <code>java.lang.Throwable</code>.
12686 The exception may have been thrown by a Java programming language or native
12687 method, but in the case of native methods, the event is not generated
12688 until the exception is first seen by a Java programming language method. If an exception is
12689 set and cleared in a native method (and thus is never visible to Java programming language code),
12690 no exception event is generated.
12691 <p/>
12692 The <code>method</code> and <code>location</code>
12693 parameters uniquely identify the current location
12694 (where the exception was detected) and allow
12695 the mapping to source file and line number when that information is
12696 available. The <code>exception</code> field identifies the thrown
12697 exception object. The <code>catch_method</code>
12698 and <code>catch_location</code> identify the location of the catch clause,
12699 if any, that handles the thrown exception. If there is no such catch clause,
12700 each field is set to 0. There is no guarantee that the thread will ever
12701 reach this catch clause. If there are native methods on the call stack
12702 between the throw location and the catch clause, the exception may
12703 be reset by one of those native methods.
12704 Similarly, exceptions that are reported as uncaught (<code>catch_klass</code>
12705 et al. set to 0) may in fact be caught by native code.
12706 Agents can check for these occurrences by monitoring
12707 <eventlink id="ExceptionCatch"></eventlink> events.
12708 Note that finally clauses are implemented as catch and re-throw. Therefore they
12709 will be reported in the catch location.
12710 </description>
12711 <origin>jvmdi</origin>
12712 <capabilities>
12713 <required id="can_generate_exception_events"></required>
12714 </capabilities>
12715 <parameters>
12716 <param id="jni_env">
12717 <outptr>
12718 <struct>JNIEnv</struct>
12719 </outptr>
12720 <description>
12721 The JNI environment of the event (current) thread
12722 </description>
12723 </param>
12724 <param id="thread">
12725 <jthread/>
12726 <description>
12727 Thread generating the exception
12728 </description>
12729 </param>
12730 <param id="klass">
12731 <jclass method="method"/>
12732 <description>
12733 Class generating the exception
12734 </description>
12735 </param>
12736 <param id="method">
12737 <jmethodID class="klass"/>
12738 <description>
12739 Method generating the exception
12740 </description>
12741 </param>
12742 <param id="location">
12743 <jlocation/>
12744 <description>
12745 Location where exception occurred
12746 </description>
12747 </param>
12748 <param id="exception">
12749 <jobject/>
12750 <description>
12751 The exception being thrown
12752 </description>
12753 </param>
12754 <param id="catch_klass">
12755 <jclass method="catch_method"/>
12756 <description>
12757 Class that will catch the exception, or <code>NULL</code> if no known catch
12758 </description>
12759 </param>
12760 <param id="catch_method">
12761 <jmethodID class="catch_klass"/>
12762 <description>
12763 Method that will catch the exception, or <code>NULL</code> if no known catch
12764 </description>
12765 </param>
12766 <param id="catch_location">
12767 <jlocation/>
12768 <description>
12769 location which will catch the exception or zero if no known catch
12770 </description>
12771 </param>
12772 </parameters>
12773 </event>
12774
12775 <event label="Exception Catch"
12776 id="ExceptionCatch" const="JVMTI_EVENT_EXCEPTION_CATCH" filtered="thread" num="59">
12777 <description>
12778 Exception catch events are generated whenever a thrown exception is caught.
12779 Where "exception" means any <code>java.lang.Throwable</code>.
12780 If the exception is caught in a Java programming language method, the event is generated
12781 when the catch clause is reached. If the exception is caught in a native
12782 method, the event is generated as soon as control is returned to a Java programming language
12783 method. Exception catch events are generated for any exception for which
12784 a throw was detected in a Java programming language method.
12785 Note that finally clauses are implemented as catch and re-throw. Therefore they
12786 will generate exception catch events.
12787 <p/>
12788 The <code>method</code> and <code>location</code>
12789 parameters uniquely identify the current location
12790 and allow the mapping to source file and line number when that information is
12791 available. For exceptions caught in a Java programming language method, the
12792 <code>exception</code> object identifies the exception object. Exceptions
12793 caught in native methods are not necessarily available by the time the
12794 exception catch is reported, so the <code>exception</code> field is set
12795 to <code>NULL</code>.
12796 </description>
12797 <origin>jvmdi</origin>
12798 <capabilities>
12799 <required id="can_generate_exception_events"></required>
12800 </capabilities>
12801 <parameters>
12802 <param id="jni_env">
12803 <outptr>
12804 <struct>JNIEnv</struct>
12805 </outptr>
12806 <description>
12807 The JNI environment of the event (current) thread
12808 </description>
12809 </param>
12810 <param id="thread">
12811 <jthread/>
12812 <description>
12813 Thread catching the exception
12814 </description>
12815 </param>
12816 <param id="klass">
12817 <jclass method="method"/>
12818 <description>
12819 Class catching the exception
12820 </description>
12821 </param>
12822 <param id="method">
12823 <jmethodID class="klass"/>
12824 <description>
12825 Method catching the exception
12826 </description>
12827 </param>
12828 <param id="location">
12829 <jlocation/>
12830 <description>
12831 Location where exception is being caught
12832 </description>
12833 </param>
12834 <param id="exception">
12835 <jobject/>
12836 <description>
12837 Exception being caught
12838 </description>
12839 </param>
12840 </parameters>
12841 </event>
12842
12843 <event label="Thread Start"
12844 id="ThreadStart" const="JVMTI_EVENT_THREAD_START" num="52" phase="start">
12845 <description>
12846 Thread start events are generated by a new thread before its initial
12847 method executes.
12848 <p/>
12849 A thread may be listed in the array returned by
12850 <functionlink id="GetAllThreads"></functionlink>
12851 before its thread start event is generated.
12852 It is possible for other events to be generated
12853 on a thread before its thread start event.
12854 <p/>
12855 The event is sent on the newly started <paramlink id="thread"></paramlink>.
12856 </description>
12857 <origin>jvmdi</origin>
12858 <capabilities>
12859 </capabilities>
12860 <parameters>
12861 <param id="jni_env">
12862 <outptr>
12863 <struct>JNIEnv</struct>
12864 </outptr>
12865 <description>
12866 The JNI environment of the event (current) thread.
12867 </description>
12868 </param>
12869 <param id="thread">
12870 <jthread/>
12871 <description>
12872 Thread starting
12873 </description>
12874 </param>
12875 </parameters>
12876 </event>
12877
12878 <event label="Thread End"
12879 id="ThreadEnd" const="JVMTI_EVENT_THREAD_END" filtered="thread" num="53" phase="start">
12880 <description>
12881 Thread end events are generated by a terminating thread
12882 after its initial method has finished execution.
12883 <p/>
12884 A thread may be listed in the array returned by
12885 <functionlink id="GetAllThreads"></functionlink>
12886 after its thread end event is generated.
12887 No events are generated on a thread
12888 after its thread end event.
12889 <p/>
12890 The event is sent on the dying <paramlink id="thread"></paramlink>.
12891 </description>
12892 <origin>jvmdi</origin>
12893 <capabilities>
12894 </capabilities>
12895 <parameters>
12896 <param id="jni_env">
12897 <outptr>
12898 <struct>JNIEnv</struct>
12899 </outptr>
12900 <description>
12901 The JNI environment of the event (current) thread.
12902 </description>
12903 </param>
12904 <param id="thread">
12905 <jthread/>
12906 <description>
12907 Thread ending
12908 </description>
12909 </param>
12910 </parameters>
12911 </event>
12912
12913 <event label="Class Load"
12914 id="ClassLoad" const="JVMTI_EVENT_CLASS_LOAD" filtered="thread" phase="start" num="55">
12915 <description>
12916 A class load event is generated when a class is first loaded. The order
12917 of class load events generated by a particular thread are guaranteed
12918 to match the order of class loading within that thread.
12919 Array class creation does not generate a class load event.
12920 The creation of a primitive class (for example, java.lang.Integer.TYPE)
12921 does not generate a class load event.
12922 <p/>
12923 This event is sent at an early stage in loading the class. As
12924 a result the class should be used carefully. Note, for example,
12925 that methods and fields are not yet loaded, so queries for methods,
12926 fields, subclasses, and so on will not give correct results.
12927 See "Loading of Classes and Interfaces" in the <i>Java Language
12928 Specification</i>. For most
12929 purposes the <eventlink id="ClassPrepare"></eventlink> event will
12930 be more useful.
12931 </description>
12932 <origin>jvmdi</origin>
12933 <capabilities>
12934 </capabilities>
12935 <parameters>
12936 <param id="jni_env">
12937 <outptr>
12938 <struct>JNIEnv</struct>
12939 </outptr>
12940 <description>
12941 The JNI environment of the event (current) thread
12942 </description>
12943 </param>
12944 <param id="thread">
12945 <jthread/>
12946 <description>
12947 Thread loading the class
12948 </description>
12949 </param>
12950 <param id="klass">
12951 <jclass/>
12952 <description>
12953 Class being loaded
12954 </description>
12955 </param>
12956 </parameters>
12957 </event>
12958
12959 <elide>
12960 <event label="Class Unload"
12961 id="ClassUnload" const="JVMTI_EVENT_CLASS_UNLOAD" num="57">
12962 <description>
12963 A class unload event is generated when the class is about to be unloaded.
12964 Class unload events take place during garbage collection and must be
12965 handled extremely carefully. The garbage collector holds many locks
12966 and has suspended all other threads, so the event handler cannot depend
12967 on the ability to acquire any locks. The class unload event handler should
12968 do as little as possible, perhaps by queuing information to be processed
12969 later. In particular, the <code>jclass</code> should be used only in
12970 the JNI function <code>isSameObject</code> or in the following <jvmti/> functions:
12971 <ul>
12972 <li><functionlink id="GetClassSignature"></functionlink></li>
12973 <li><functionlink id="GetSourceFileName"></functionlink></li>
12974 <li><functionlink id="IsInterface"></functionlink></li>
12975 <li><functionlink id="IsArrayClass"></functionlink></li>
12976 </ul>
12977 </description>
12978 <origin>jvmdi</origin>
12979 <capabilities>
12980 </capabilities>
12981 <parameters>
12982 <param id="jni_env">
12983 <outptr>
12984 <struct>JNIEnv</struct>
12985 </outptr>
12986 <description>
12987 The JNI environment of the event (current) thread
12988 </description>
12989 </param>
12990 <param id="thread">
12991 <jthread/>
12992 <description>
12993 Thread generating the class unload
12994 </description>
12995 </param>
12996 <param id="klass">
12997 <jclass/>
12998 <description>
12999 Class being unloaded
13000 </description>
13001 </param>
13002 </parameters>
13003 </event>
13004 </elide>
13005
13006 <event label="Class Prepare"
13007 id="ClassPrepare" const="JVMTI_EVENT_CLASS_PREPARE" filtered="thread" phase="start" num="56">
13008 <description>
13009 A class prepare event is generated when class preparation is complete.
13010 At this point, class fields, methods, and implemented interfaces are
13011 available, and no code from the class has been executed. Since array
13012 classes never have fields or methods, class prepare events are not
13013 generated for them. Class prepare events are not generated for
13014 primitive classes (for example, <code>java.lang.Integer.TYPE</code>).
13015 </description>
13016 <origin>jvmdi</origin>
13017 <capabilities>
13018 </capabilities>
13019 <parameters>
13020 <param id="jni_env">
13021 <outptr>
13022 <struct>JNIEnv</struct>
13023 </outptr>
13024 <description>
13025 The JNI environment of the event (current) thread
13026 </description>
13027 </param>
13028 <param id="thread">
13029 <jthread/>
13030 <description>
13031 Thread generating the class prepare
13032 </description>
13033 </param>
13034 <param id="klass">
13035 <jclass/>
13036 <description>
13037 Class being prepared
13038 </description>
13039 </param>
13040 </parameters>
13041 </event>
13042
13043 <event label="Class File Load Hook" phase="any"
13044 id="ClassFileLoadHook" const="JVMTI_EVENT_CLASS_FILE_LOAD_HOOK" num="54">
13045 <description>
13046 This event is sent when the VM obtains class file data,
13047 but before it constructs
13048 the in-memory representation for that class.
13049 This event is also sent when the class is being modified by the
13050 <functionlink id="RetransformClasses"/> function or
13051 the <functionlink id="RedefineClasses"/> function,
13052 called in any <jvmti/> environment.
13053 The agent can instrument
13054 the existing class file data sent by the VM to include profiling/debugging hooks.
13055 See the description of
13056 <internallink id="bci">bytecode instrumentation</internallink>
13057 for usage information.
13058 <p/>
13059 When the capabilities
13060 <internallink id="jvmtiCapabilities.can_generate_early_class_hook_events">
13061 <code>can_generate_early_class_hook_events</code></internallink> and
13062 <internallink id="jvmtiCapabilities.can_generate_all_class_hook_events">
13063 <code>can_generate_all_class_hook_events</code></internallink>
13064 are enabled then this event may be sent in the primordial phase.
13065 Otherwise, this event may be sent before the VM is initialized (the start
13066 <functionlink id="GetPhase">phase</functionlink>).
13067 Some classes might not be compatible
13068 with the function (eg. ROMized classes or implementation defined classes) and this event will
13069 not be generated for these classes.
13070 <p/>
13071 The agent must allocate the space for the modified
13072 class file data buffer
13073 using the memory allocation function
13074 <functionlink id="Allocate"></functionlink> because the
13075 VM is responsible for freeing the new class file data buffer
13076 using <functionlink id="Deallocate"></functionlink>.
13077 <p/>
13078 If the agent wishes to modify the class file, it must set
13079 <code>new_class_data</code> to point
13080 to the newly instrumented class file data buffer and set
13081 <code>new_class_data_len</code> to the length of that
13082 buffer before returning
13083 from this call. If no modification is desired, the agent simply
13084 does not set <code>new_class_data</code>. If multiple agents
13085 have enabled this event the results are chained. That is, if
13086 <code>new_class_data</code> has been set, it becomes the
13087 <code>class_data</code> for the next agent.
13088 <p/>
13089 When handling a class load in the live phase, then the
13090 <functionlink id="GetNamedModule"></functionlink>
13091 function can be used to map class loader and a package name to a module.
13092 When a class is being redefined or retransformed then
13093 <code>class_being_redefined</code> is non <code>NULL</code> and so
13094 the JNI <code>GetModule</code> function can also be used
13095 to obtain the Module.
13096 <p/>
13097 The order that this event is sent to each environment differs
13098 from other events.
13099 This event is sent to environments in the following order:
13100 <ul>
13101 <li><fieldlink id="can_retransform_classes"
13102 struct="jvmtiCapabilities">retransformation
13103 incapable</fieldlink>
13104 environments, in the
13105 order in which they were created
13106 </li>
13107 <li><fieldlink id="can_retransform_classes"
13108 struct="jvmtiCapabilities">retransformation
13109 capable</fieldlink>
13110 environments, in the
13111 order in which they were created
13112 </li>
13113 </ul>
13114 When triggered by <functionlink id="RetransformClasses"/>,
13115 this event is sent only to <fieldlink id="can_retransform_classes"
13116 struct="jvmtiCapabilities">retransformation
13117 capable</fieldlink>
13118 environments.
13119 </description>
13120 <origin>jvmpi</origin>
13121 <capabilities>
13122 <capability id="can_generate_all_class_hook_events"></capability>
13123 <capability id="can_generate_early_class_hook_events"></capability>
13124 </capabilities>
13125 <parameters>
13126 <param id="jni_env">
13127 <outptr>
13128 <struct>JNIEnv</struct>
13129 </outptr>
13130 <description>
13131 The JNI environment of the event (current) thread.
13132 </description>
13133 </param>
13134 <param id="class_being_redefined">
13135 <jclass/>
13136 <description>
13137 The class being
13138 <functionlink id="RedefineClasses">redefined</functionlink> or
13139 <functionlink id="RetransformClasses">retransformed</functionlink>.
13140 <code>NULL</code> if sent by class load.
13141 </description>
13142 </param>
13143 <param id="loader">
13144 <jobject/>
13145 <description>
13146 The class loader loading the class.
13147 <code>NULL</code> if the bootstrap class loader.
13148 </description>
13149 </param>
13150 <param id="name">
13151 <vmbuf><char/></vmbuf>
13152 <description>
13153 Name of class being loaded as a VM internal qualified name
13154 (for example, "java/util/List"), encoded as a
13155 <internallink id="mUTF">modified UTF-8</internallink> string.
13156 Note: if the class is defined with a <code>NULL</code> name or
13157 without a name specified, <code>name</code> will be <code>NULL</code>.
13158 </description>
13159 </param>
13160 <param id="protection_domain">
13161 <jobject/>
13162 <description>
13163 The <code>ProtectionDomain</code> of the class.
13164 </description>
13165 </param>
13166 <param id="class_data_len">
13167 <jint/>
13168 <description>
13169 Length of current class file data buffer.
13170 </description>
13171 </param>
13172 <param id="class_data">
13173 <vmbuf><uchar/></vmbuf>
13174 <description>
13175 Pointer to the current class file data buffer.
13176 </description>
13177 </param>
13178 <param id="new_class_data_len">
13179 <outptr><jint/></outptr>
13180 <description>
13181 Pointer to the length of the new class file data buffer.
13182 </description>
13183 </param>
13184 <param id="new_class_data">
13185 <agentbuf incount="new_class_data_len"><uchar/></agentbuf>
13186 <description>
13187 Pointer to the pointer to the instrumented class file data buffer.
13188 </description>
13189 </param>
13190 </parameters>
13191 </event>
13192
13193 <event label="VM Start Event"
13194 id="VMStart" const="JVMTI_EVENT_VM_START" num="57" phase="start">
13195 <description>
13196 The VM start event signals the start of the VM.
13197 At this time JNI is live but the VM is not yet fully initialized.
13198 Once this event is generated, the agent is free to call any JNI function.
13199 This event signals the beginning of the start phase,
13200 <jvmti/> functions permitted in the start phase may be called.
13201 <p/>
13202 The timing of this event may depend on whether the agent has added the
13203 <internallink id="jvmtiCapabilities.can_generate_early_vmstart">
13204 <code>can_generate_early_vmstart</code></internallink> capability or not.
13205 If the capability has been added then the VM posts the event as early
13206 as possible. The VM is capable of executing bytecode but it may not have
13207 initialized to the point where it can load classes in modules other than
13208 <code>java.base</code>, or even arbitrary classes in <code>java.base</code>.
13209 Agents that do load-time instrumentation in this
13210 phase must take great care when instrumenting code that potentially
13211 executes in this phase. Extreme care should also be taken with JNI
13212 <code>FindClass</code> as it may not be possible to load classes and attempts
13213 to do so may result in unpredictable behavior, maybe even stability issues
13214 on some VM implementations.
13215 If the capability has not been added then the VM delays posting this
13216 event until it is capable of loading classes in modules other than
13217 <code>java.base</code> or the VM has completed its initialization.
13218 Agents that create more than one JVM TI environment, where the
13219 capability is added to some but not all environments, may observe the
13220 start phase beginning earlier in the JVM TI environments that possess
13221 the capabilty.
13222 <p/>
13223 In the case of VM start-up failure, this event will not be sent.
13224 </description>
13225 <origin>jvmdi</origin>
13226 <capabilities>
13227 </capabilities>
13228 <parameters>
13229 <param id="jni_env">
13230 <outptr>
13231 <struct>JNIEnv</struct>
13232 </outptr>
13233 <description>
13234 The JNI environment of the event (current) thread.
13235 </description>
13236 </param>
13237 </parameters>
13238 </event>
13239
13240 <event label="VM Initialization Event"
13241 id="VMInit" const="JVMTI_EVENT_VM_INIT" num="50">
13242 <description>
13243 The VM initialization event signals the completion of VM initialization. Once
13244 this event is generated, the agent is free to call any JNI or <jvmti/>
13245 function. The VM initialization event can be preceded by or can be concurrent
13246 with other events, but
13247 the preceding events should be handled carefully, if at all, because the
13248 VM has not completed its initialization. The thread start event for the
13249 main application thread is guaranteed not to occur until after the
13250 handler for the VM initialization event returns.
13251 <p/>
13252 In the case of VM start-up failure, this event will not be sent.
13253 </description>
13254 <origin>jvmdi</origin>
13255 <capabilities>
13256 </capabilities>
13257 <parameters>
13258 <param id="jni_env">
13259 <outptr>
13260 <struct>JNIEnv</struct>
13261 </outptr>
13262 <description>
13263 The JNI environment of the event (current) thread.
13264 </description>
13265 </param>
13266 <param id="thread">
13267 <jthread/>
13268 <description>
13269 The initial thread
13270 </description>
13271 </param>
13272 </parameters>
13273 </event>
13274
13275 <event label="VM Death Event"
13276 id="VMDeath" const="JVMTI_EVENT_VM_DEATH" num="51">
13277 <description>
13278 The VM death event notifies the agent of the termination of the VM.
13279 No events will occur after the VMDeath event.
13280 <p/>
13281 In the case of VM start-up failure, this event will not be sent.
13282 Note that <internallink id="onunload">Agent_OnUnload</internallink>
13283 will still be called in these cases.
13284 </description>
13285 <origin>jvmdi</origin>
13286 <capabilities>
13287 </capabilities>
13288 <parameters>
13289 <param id="jni_env">
13290 <outptr>
13291 <struct>JNIEnv</struct>
13292 </outptr>
13293 <description>
13294 The JNI environment of the event (current) thread
13295 </description>
13296 </param>
13297 </parameters>
13298 </event>
13299
13300 <event label="Compiled Method Load" phase="start"
13301 id="CompiledMethodLoad" const="JVMTI_EVENT_COMPILED_METHOD_LOAD" num="68">
13302 <description>
13303 Sent when a method is compiled and loaded into memory by the VM.
13304 If it is unloaded, the <eventlink id="CompiledMethodUnload"/> event is sent.
13305 If it is moved, the <eventlink id="CompiledMethodUnload"/> event is sent,
13306 followed by a new <code>CompiledMethodLoad</code> event.
13307 Note that a single method may have multiple compiled forms, and that
13308 this event will be sent for each form.
13309 Note also that several methods may be inlined into a single
13310 address range, and that this event will be sent for each method.
13311 <p/>
13312 These events can be sent after their initial occurrence with
13313 <functionlink id="GenerateEvents"></functionlink>.
13314 </description>
13315 <origin>jvmpi</origin>
13316 <typedef id="jvmtiAddrLocationMap" label="Native address to location entry">
13317 <field id="start_address">
13318 <vmbuf><void/></vmbuf>
13319 <description>
13320 Starting native address of code corresponding to a location
13321 </description>
13322 </field>
13323 <field id="location">
13324 <jlocation/>
13325 <description>
13326 Corresponding location. See
13327 <functionlink id="GetJLocationFormat"></functionlink>
13328 for the meaning of location.
13329 </description>
13330 </field>
13331 </typedef>
13332 <capabilities>
13333 <required id="can_generate_compiled_method_load_events"></required>
13334 </capabilities>
13335 <parameters>
13336 <param id="klass">
13337 <jclass method="method"/>
13338 <description>
13339 Class of the method being compiled and loaded
13340 </description>
13341 </param>
13342 <param id="method">
13343 <jmethodID class="klass"/>
13344 <description>
13345 Method being compiled and loaded
13346 </description>
13347 </param>
13348 <param id="code_size">
13349 <jint/>
13350 <description>
13351 Size of compiled code
13352 </description>
13353 </param>
13354 <param id="code_addr">
13355 <vmbuf><void/></vmbuf>
13356 <description>
13357 Address where compiled method code is loaded
13358 </description>
13359 </param>
13360 <param id="map_length">
13361 <jint/>
13362 <description>
13363 Number of <typelink id="jvmtiAddrLocationMap"></typelink>
13364 entries in the address map.
13365 Zero if mapping information cannot be supplied.
13366 </description>
13367 </param>
13368 <param id="map">
13369 <vmbuf><struct>jvmtiAddrLocationMap</struct></vmbuf>
13370 <description>
13371 Map from native addresses to location.
13372 The native address range of each entry is from
13373 <fieldlink id="start_address" struct="jvmtiAddrLocationMap"></fieldlink>
13374 to <code>start_address-1</code> of the next entry.
13375 <code>NULL</code> if mapping information cannot be supplied.
13376 </description>
13377 </param>
13378 <param id="compile_info">
13379 <vmbuf><void/></vmbuf>
13380 <description>
13381 VM-specific compilation information.
13382 The referenced compile information is managed by the VM
13383 and must not depend on the agent for collection.
13384 A VM implementation defines the content and lifetime
13385 of the information.
13386 </description>
13387 </param>
13388 </parameters>
13389 </event>
13390
13391 <event label="Compiled Method Unload" phase="start"
13392 id="CompiledMethodUnload" const="JVMTI_EVENT_COMPILED_METHOD_UNLOAD" num="69">
13393 <description>
13394 Sent when a compiled method is unloaded from memory.
13395 This event might not be sent on the thread which performed the unload.
13396 This event may be sent sometime after the unload occurs, but
13397 will be sent before the memory is reused
13398 by a newly generated compiled method. This event may be sent after
13399 the class is unloaded.
13400 </description>
13401 <origin>jvmpi</origin>
13402 <capabilities>
13403 <required id="can_generate_compiled_method_load_events"></required>
13404 </capabilities>
13405 <parameters>
13406 <param id="klass">
13407 <jclass method="method"/>
13408 <description>
13409 Class of the compiled method being unloaded.
13410 </description>
13411 </param>
13412 <param id="method">
13413 <jmethodID class="klass"/>
13414 <description>
13415 Compiled method being unloaded.
13416 For identification of the compiled method only -- the class
13417 may be unloaded and therefore the method should not be used
13418 as an argument to further JNI or <jvmti/> functions.
13419 </description>
13420 </param>
13421 <param id="code_addr">
13422 <vmbuf><void/></vmbuf>
13423 <description>
13424 Address where compiled method code was loaded.
13425 For identification of the compiled method only --
13426 the space may have been reclaimed.
13427 </description>
13428 </param>
13429 </parameters>
13430 </event>
13431
13432 <event label="Dynamic Code Generated" phase="any"
13433 id="DynamicCodeGenerated" const="JVMTI_EVENT_DYNAMIC_CODE_GENERATED" num="70">
13434 <description>
13435 Sent when a component of the virtual machine is generated dynamically.
13436 This does not correspond to Java programming language code that is
13437 compiled--see <eventlink id="CompiledMethodLoad"></eventlink>.
13438 This is for native code--for example, an interpreter that is generated
13439 differently depending on command-line options.
13440 <p/>
13441 Note that this event has no controlling capability.
13442 If a VM cannot generate these events, it simply does not send any.
13443 <p/>
13444 These events can be sent after their initial occurrence with
13445 <functionlink id="GenerateEvents"></functionlink>.
13446 </description>
13447 <origin>jvmpi</origin>
13448 <capabilities>
13449 </capabilities>
13450 <parameters>
13451 <param id="name">
13452 <vmbuf><char/></vmbuf>
13453 <description>
13454 Name of the code, encoded as a
13455 <internallink id="mUTF">modified UTF-8</internallink> string.
13456 Intended for display to an end-user.
13457 The name might not be unique.
13458 </description>
13459 </param>
13460 <param id="address">
13461 <vmbuf><void/></vmbuf>
13462 <description>
13463 Native address of the code
13464 </description>
13465 </param>
13466 <param id="length">
13467 <jint/>
13468 <description>
13469 Length in bytes of the code
13470 </description>
13471 </param>
13472 </parameters>
13473 </event>
13474
13475 <event label="Data Dump Request"
13476 id="DataDumpRequest" const="JVMTI_EVENT_DATA_DUMP_REQUEST" num="71">
13477 <description>
13478 Sent by the VM to request the agent to dump its data. This
13479 is just a hint and the agent need not react to this event.
13480 This is useful for processing command-line signals from users. For
13481 example, in the Java 2 SDK a CTRL-Break on Win32 and a CTRL-\ on Solaris
13482 causes the VM to send this event to the agent.
13483 </description>
13484 <origin>jvmpi</origin>
13485 <capabilities>
13486 </capabilities>
13487 <parameters>
13488 </parameters>
13489 </event>
13490
13491 <event label="Monitor Contended Enter"
13492 id="MonitorContendedEnter" const="JVMTI_EVENT_MONITOR_CONTENDED_ENTER" filtered="thread" num="75">
13493 <description>
13494 Sent when a thread is attempting to enter a Java programming language
13495 monitor already acquired by another thread.
13496 </description>
13497 <origin>jvmpi</origin>
13498 <capabilities>
13499 <required id="can_generate_monitor_events"></required>
13500 </capabilities>
13501 <parameters>
13502 <param id="jni_env">
13503 <outptr>
13504 <struct>JNIEnv</struct>
13505 </outptr>
13506 <description>
13507 The JNI environment of the event (current) thread
13508 </description>
13509 </param>
13510 <param id="thread">
13511 <jthread/>
13512 <description>
13513 JNI local reference to the thread
13514 attempting to enter the monitor
13515 </description>
13516 </param>
13517 <param id="object">
13518 <jobject/>
13519 <description>
13520 JNI local reference to the monitor
13521 </description>
13522 </param>
13523 </parameters>
13524 </event>
13525
13526 <event label="Monitor Contended Entered"
13527 id="MonitorContendedEntered" const="JVMTI_EVENT_MONITOR_CONTENDED_ENTERED" filtered="thread" num="76">
13528 <description>
13529 Sent when a thread enters a Java programming language
13530 monitor after waiting for it to be released by another thread.
13531 </description>
13532 <origin>jvmpi</origin>
13533 <capabilities>
13534 <required id="can_generate_monitor_events"></required>
13535 </capabilities>
13536 <parameters>
13537 <param id="jni_env">
13538 <outptr>
13539 <struct>JNIEnv</struct>
13540 </outptr>
13541 <description>
13542 The JNI environment of the event (current) thread
13543 </description>
13544 </param>
13545 <param id="thread">
13546 <jthread/>
13547 <description>
13548 JNI local reference to the thread entering
13549 the monitor
13550 </description>
13551 </param>
13552 <param id="object">
13553 <jobject/>
13554 <description>
13555 JNI local reference to the monitor
13556 </description>
13557 </param>
13558 </parameters>
13559 </event>
13560
13561 <event label="Monitor Wait"
13562 id="MonitorWait" const="JVMTI_EVENT_MONITOR_WAIT" filtered="thread" num="73">
13563 <description>
13564 Sent when a thread is about to wait on an object.
13565 </description>
13566 <origin>jvmpi</origin>
13567 <capabilities>
13568 <required id="can_generate_monitor_events"></required>
13569 </capabilities>
13570 <parameters>
13571 <param id="jni_env">
13572 <outptr>
13573 <struct>JNIEnv</struct>
13574 </outptr>
13575 <description>
13576 The JNI environment of the event (current) thread
13577 </description>
13578 </param>
13579 <param id="thread">
13580 <jthread/>
13581 <description>
13582 JNI local reference to the thread about to wait
13583 </description>
13584 </param>
13585 <param id="object">
13586 <jobject/>
13587 <description>
13588 JNI local reference to the monitor
13589 </description>
13590 </param>
13591 <param id="timeout">
13592 <jlong/>
13593 <description>
13594 The number of milliseconds the thread will wait
13595 </description>
13596 </param>
13597 </parameters>
13598 </event>
13599
13600 <event label="Monitor Waited"
13601 id="MonitorWaited" const="JVMTI_EVENT_MONITOR_WAITED" filtered="thread" num="74">
13602 <description>
13603 Sent when a thread finishes waiting on an object.
13604 </description>
13605 <origin>jvmpi</origin>
13606 <capabilities>
13607 <required id="can_generate_monitor_events"></required>
13608 </capabilities>
13609 <parameters>
13610 <param id="jni_env">
13611 <outptr>
13612 <struct>JNIEnv</struct>
13613 </outptr>
13614 <description>
13615 The JNI environment of the event (current) thread
13616 </description>
13617 </param>
13618 <param id="thread">
13619 <jthread/>
13620 <description>
13621 JNI local reference to the thread that was finished waiting
13622 </description>
13623 </param>
13624 <param id="object">
13625 <jobject/>
13626 <description>
13627 JNI local reference to the monitor.
13628 </description>
13629 </param>
13630 <param id="timed_out">
13631 <jboolean/>
13632 <description>
13633 True if the monitor timed out
13634 </description>
13635 </param>
13636 </parameters>
13637 </event>
13638
13639 <event label="Resource Exhausted"
13640 id="ResourceExhausted" const="JVMTI_EVENT_RESOURCE_EXHAUSTED" num="80"
13641 since="1.1">
13642 <description>
13643 Sent when a VM resource needed by a running application has been exhausted.
13644 Except as required by the optional capabilities, the set of resources
13645 which report exhaustion is implementation dependent.
13646 <p/>
13647 The following bit flags define the properties of the resource exhaustion:
13648 <constants id="jvmtiResourceExhaustionFlags"
13649 label="Resource Exhaustion Flags"
13650 kind="bits"
13651 since="1.1">
13652 <constant id="JVMTI_RESOURCE_EXHAUSTED_OOM_ERROR" num="0x0001">
13653 After this event returns, the VM will throw a
13654 <code>java.lang.OutOfMemoryError</code>.
13655 </constant>
13656 <constant id="JVMTI_RESOURCE_EXHAUSTED_JAVA_HEAP" num="0x0002">
13657 The VM was unable to allocate memory from the <tm>Java</tm>
13658 platform <i>heap</i>.
13659 The <i>heap</i> is the runtime
13660 data area from which memory for all class instances and
13661 arrays are allocated.
13662 </constant>
13663 <constant id="JVMTI_RESOURCE_EXHAUSTED_THREADS" num="0x0004">
13664 The VM was unable to create a thread.
13665 </constant>
13666 </constants>
13667 </description>
13668 <origin>new</origin>
13669 <capabilities>
13670 <capability id="can_generate_resource_exhaustion_heap_events">
13671 Can generate events when the VM is unable to allocate memory from the
13672 <internallink id="JVMTI_RESOURCE_EXHAUSTED_JAVA_HEAP">heap</internallink>.
13673 </capability>
13674 <capability id="can_generate_resource_exhaustion_threads_events">
13675 Can generate events when the VM is unable to
13676 <internallink id="JVMTI_RESOURCE_EXHAUSTED_THREADS">create
13677 a thread</internallink>.
13678 </capability>
13679 </capabilities>
13680 <parameters>
13681 <param id="jni_env">
13682 <outptr>
13683 <struct>JNIEnv</struct>
13684 </outptr>
13685 <description>
13686 The JNI environment of the event (current) thread
13687 </description>
13688 </param>
13689 <param id="flags">
13690 <jint/>
13691 <description>
13692 Flags defining the properties of the of resource exhaustion
13693 as specified by the
13694 <internallink id="jvmtiResourceExhaustionFlags">Resource
13695 Exhaustion Flags</internallink>.
13696 </description>
13697 </param>
13698 <param id="reserved">
13699 <vmbuf><void/></vmbuf>
13700 <description>
13701 Reserved.
13702 </description>
13703 </param>
13704 <param id="description">
13705 <vmbuf><char/></vmbuf>
13706 <description>
13707 Description of the resource exhaustion, encoded as a
13708 <internallink id="mUTF">modified UTF-8</internallink> string.
13709 </description>
13710 </param>
13711 </parameters>
13712 </event>
13713
13714 <event label="VM Object Allocation"
13715 id="VMObjectAlloc" const="JVMTI_EVENT_VM_OBJECT_ALLOC" num="84">
13716 <description>
13717 Sent when a method causes the virtual machine to allocate an
13718 Object visible to Java programming language code and the
13719 allocation is not detectable by other intrumentation mechanisms.
13720 Generally object allocation should be detected by instrumenting
13721 the bytecodes of allocating methods.
13722 Object allocation generated in native code by JNI function
13723 calls should be detected using
13724 <internallink id="jniIntercept">JNI function interception</internallink>.
13725 Some methods might not have associated bytecodes and are not
13726 native methods, they instead are executed directly by the
13727 VM. These methods should send this event.
13728 Virtual machines which are incapable of bytecode instrumentation
13729 for some or all of their methods can send this event.
13730 <p/>
13731 Typical examples where this event might be sent:
13732 <ul>
13733 <li>Reflection -- for example, <code>java.lang.Class.newInstance()</code></li>
13734 <li>Methods not represented by bytecodes -- for example, VM intrinsics and
13735 J2ME preloaded classes</li>
13736 </ul>
13737 Cases where this event would not be generated:
13738 <ul>
13739 <li>Allocation due to bytecodes -- for example, the <code>new</code>
13740 and <code>newarray</code> VM instructions</li>
13741 <li>Allocation due to JNI function calls -- for example,
13742 <code>AllocObject</code></li>
13743 <li>Allocations during VM initialization</li>
13744 <li>VM internal objects</li>
13745 </ul>
13746 </description>
13747 <origin>new</origin>
13748 <capabilities>
13749 <required id="can_generate_vm_object_alloc_events"></required>
13750 </capabilities>
13751 <parameters>
13752 <param id="jni_env">
13753 <outptr>
13754 <struct>JNIEnv</struct>
13755 </outptr>
13756 <description>
13757 The JNI environment of the event (current) thread
13758 </description>
13759 </param>
13760 <param id="thread">
13761 <jthread/>
13762 <description>
13763 Thread allocating the object.
13764 </description>
13765 </param>
13766 <param id="object">
13767 <jobject/>
13768 <description>
13769 JNI local reference to the object that was allocated
13770 </description>
13771 </param>
13772 <param id="object_klass">
13773 <jclass/>
13774 <description>
13775 JNI local reference to the class of the object
13776 </description>
13777 </param>
13778 <param id="size">
13779 <jlong/>
13780 <description>
13781 Size of the object (in bytes). See <functionlink id="GetObjectSize"/>.
13782 </description>
13783 </param>
13784 </parameters>
13785 </event>
13786
13787 <event label="Object Free"
13788 id="ObjectFree" const="JVMTI_EVENT_OBJECT_FREE" num="83">
13789 <description>
13790 An Object Free event is sent when the garbage collector frees an object.
13791 Events are only sent for tagged objects--see
13792 <internallink id="Heap">heap functions</internallink>.
13793 <p/>
13794 The event handler must not use JNI functions and
13795 must not use <jvmti/> functions except those which
13796 specifically allow such use (see the raw monitor, memory management,
13797 and environment local storage functions).
13798 </description>
13799 <origin>new</origin>
13800 <capabilities>
13801 <required id="can_generate_object_free_events"></required>
13802 </capabilities>
13803 <parameters>
13804 <param id="tag">
13805 <jlong/>
13806 <description>
13807 The freed object's tag
13808 </description>
13809 </param>
13810 </parameters>
13811 </event>
13812
13813 <event label="Garbage Collection Start"
13814 id="GarbageCollectionStart" const="JVMTI_EVENT_GARBAGE_COLLECTION_START" num="81">
13815 <description>
13816 A Garbage Collection Start event is sent when a
13817 garbage collection pause begins.
13818 Only stop-the-world collections are reported--that is, collections during
13819 which all threads cease to modify the state of the Java virtual machine.
13820 This means that some collectors will never generate these events.
13821 This event is sent while the VM is still stopped, thus
13822 the event handler must not use JNI functions and
13823 must not use <jvmti/> functions except those which
13824 specifically allow such use (see the raw monitor, memory management,
13825 and environment local storage functions).
13826 <p/>
13827 This event is always sent as a matched pair with
13828 <eventlink id="GarbageCollectionFinish"/>
13829 (assuming both events are enabled) and no garbage collection
13830 events will occur between them.
13831 </description>
13832 <origin>new</origin>
13833 <capabilities>
13834 <required id="can_generate_garbage_collection_events"></required>
13835 </capabilities>
13836 <parameters>
13837 </parameters>
13838 </event>
13839
13840 <event label="Garbage Collection Finish"
13841 id="GarbageCollectionFinish" const="JVMTI_EVENT_GARBAGE_COLLECTION_FINISH" num="82">
13842 <description>
13843 A Garbage Collection Finish event is sent when a
13844 garbage collection pause ends.
13845 This event is sent while the VM is still stopped, thus
13846 the event handler must not use JNI functions and
13847 must not use <jvmti/> functions except those which
13848 specifically allow such use (see the raw monitor, memory management,
13849 and environment local storage functions).
13850 <p/>
13851 Some agents may need to do post garbage collection operations that
13852 require the use of the disallowed <jvmti/> or JNI functions. For these
13853 cases an agent thread can be created which waits on a raw monitor,
13854 and the handler for the Garbage Collection Finish event simply
13855 notifies the raw monitor
13856 <p/>
13857 This event is always sent as a matched pair with
13858 <eventlink id="GarbageCollectionStart"/> (assuming both events are enabled).
13859 <issue>
13860 The most important use of this event is to provide timing information,
13861 and thus additional information is not required. However,
13862 information about the collection which is "free" should be included -
13863 what that information is needs to be determined.
13864 </issue>
13865 </description>
13866 <origin>new</origin>
13867 <capabilities>
13868 <required id="can_generate_garbage_collection_events"></required>
13869 </capabilities>
13870 <parameters>
13871 </parameters>
13872 </event>
13873
13874 <elide>
13875 <event label="Verbose Output" phase="any"
13876 id="VerboseOutput" const="JVMTI_EVENT_VERBOSE_OUTPUT" num="85">
13877 <description>
13878 Send verbose messages as strings.
13879 <issue>
13880 This format is extremely fragile, as it can change with each
13881 platform, collector and version. Alternatives include:
13882 <ul>
13883 <li>building off Java programming language M and M APIs</li>
13884 <li>XML</li>
13885 <li>key/value pairs</li>
13886 <li>removing it</li>
13887 </ul>
13888 </issue>
13889 <issue>
13890 Though this seemed trivial to implement.
13891 In the RI it appears this will be quite complex.
13892 </issue>
13893 </description>
13894 <origin>new</origin>
13895 <capabilities>
13896 </capabilities>
13897 <parameters>
13898 <param id="flag">
13899 <enum>jvmtiVerboseFlag</enum>
13900 <description>
13901 Which verbose output is being sent.
13902 </description>
13903 </param>
13904 <param id="message">
13905 <vmbuf><char/></vmbuf>
13906 <description>
13907 Message text, encoded as a
13908 <internallink id="mUTF">modified UTF-8</internallink> string.
13909 </description>
13910 </param>
13911 </parameters>
13912 </event>
13913 </elide>
13914
13915 </eventsection>
13916
13917 <datasection>
13918 <intro>
13919 <jvmti/> extends the data types defined by JNI.
13920 </intro>
13921 <basetypes id="jniTypes" label="JNI Types Used in the JVM Tool Interface">
13922 <basetype id="jboolean">
13923 <description>
13924 Holds a Java programming language <code>boolean</code>.
13925 Unsigned 8 bits.
13926 </description>
13927 </basetype>
13928 <basetype id="jchar">
13929 <description>
13930 Holds a Java programming language <code>char</code>.
13931 Unsigned 16 bits.
13932 </description>
13933 </basetype>
13934 <basetype id="jint">
13935 <description>
13936 Holds a Java programming language <code>int</code>.
13937 Signed 32 bits.
13938 </description>
13939 </basetype>
13940 <basetype id="jlong">
13941 <description>
13942 Holds a Java programming language <code>long</code>.
13943 Signed 64 bits.
13944 </description>
13945 </basetype>
13946 <basetype id="jfloat">
13947 <description>
13948 Holds a Java programming language <code>float</code>.
13949 32 bits.
13950 </description>
13951 </basetype>
13952 <basetype id="jdouble">
13953 <description>
13954 Holds a Java programming language <code>double</code>.
13955 64 bits.
13956 </description>
13957 </basetype>
13958 <basetype id="jobject">
13959 <description>
13960 Holds a Java programming language object.
13961 </description>
13962 </basetype>
13963 <basetype id="jclass">
13964 <description>
13965 Holds a Java programming language class.
13966 </description>
13967 </basetype>
13968 <basetype id="jvalue">
13969 <description>
13970 Is a union of all primitive types and <code>jobject</code>. Thus, holds any Java
13971 programming language value.
13972 </description>
13973 </basetype>
13974 <basetype id="jfieldID">
13975 <description>
13976 Identifies a Java programming language field.
13977 <code>jfieldID</code>s returned by <jvmti/> functions and events may be
13978 safely stored.
13979 </description>
13980 </basetype>
13981 <basetype id="jmethodID">
13982 <description>
13983 Identifies a Java programming language method, initializer, or constructor.
13984 <code>jmethodID</code>s returned by <jvmti/> functions and events may be
13985 safely stored. However, if the class is unloaded, they become invalid
13986 and must not be used.
13987 </description>
13988 </basetype>
13989 <basetype id="JNIEnv">
13990 <description>
13991 Pointer to the JNI function table. Pointer to this (<code>JNIEnv *</code>)
13992 is a JNI environment.
13993 </description>
13994 </basetype>
13995 </basetypes>
13996
13997 <basetypes id="jvmtiTypes" label="JVM Tool Interface Base Types">
13998 <basetype id="jvmtiEnv">
13999 <description>
14000 The <jvmti/> <internallink id="environments">environment</internallink> pointer.
14001 See the <internallink id="FunctionSection">Function Section</internallink>.
14002 <code>jvmtiEnv</code> points to the
14003 <internallink id="FunctionTable">function table</internallink> pointer.
14004 </description>
14005 </basetype>
14006 <basetype id="jthread">
14007 <definition>typedef jobject jthread;</definition>
14008 <description>
14009 Subtype of <datalink id="jobject"></datalink> that holds a thread.
14010 </description>
14011 </basetype>
14012 <basetype id="jthreadGroup">
14013 <definition>typedef jobject jthreadGroup;</definition>
14014 <description>
14015 Subtype of <datalink id="jobject"></datalink> that holds a thread group.
14016 </description>
14017 </basetype>
14018 <basetype id="jlocation">
14019 <definition>typedef jlong jlocation;</definition>
14020 <description>
14021 A 64 bit value, representing a monotonically increasing
14022 executable position within a method.
14023 <code>-1</code> indicates a native method.
14024 See <functionlink id="GetJLocationFormat"></functionlink> for the format on a
14025 given VM.
14026 </description>
14027 </basetype>
14028 <basetype id="jrawMonitorID">
14029 <definition>struct _jrawMonitorID;
14030 typedef struct _jrawMonitorID *jrawMonitorID;</definition>
14031 <description>
14032 A raw monitor.
14033 </description>
14034 </basetype>
14035 <basetype id="jvmtiError">
14036 <description>
14037 Holds an error return code.
14038 See the <internallink id="ErrorSection">Error section</internallink> for possible values.
14039 <example>
14040 typedef enum {
14041 JVMTI_ERROR_NONE = 0,
14042 JVMTI_ERROR_INVALID_THREAD = 10,
14043 ...
14044 } jvmtiError;
14045 </example>
14046 </description>
14047 </basetype>
14048 <basetype id="jvmtiEvent">
14049 <description>
14050 An identifier for an event type.
14051 See the <internallink id="EventSection">Event section</internallink> for possible values.
14052 It is guaranteed that future versions of this specification will
14053 never assign zero as an event type identifier.
14054 <example>
14055 typedef enum {
14056 JVMTI_EVENT_SINGLE_STEP = 1,
14057 JVMTI_EVENT_BREAKPOINT = 2,
14058 ...
14059 } jvmtiEvent;
14060 </example>
14061 </description>
14062 </basetype>
14063 <basetype id="jvmtiEventCallbacks" name="eventCallbacks">
14064 <description>
14065 The callbacks used for events.
14066 <example>
14067 typedef struct {
14068 jvmtiEventVMInit VMInit;
14069 jvmtiEventVMDeath VMDeath;
14070 ...
14071 } jvmtiEventCallbacks;
14072 </example>
14073 See <internallink id="jvmtiEventCallbacks">event callbacks</internallink>
14074 for the complete structure.
14075 <p/>
14076 Where, for example, the VM initialization callback is defined:
14077 <example>
14078 typedef void (JNICALL *jvmtiEventVMInit)
14079 (jvmtiEnv *jvmti_env,
14080 JNIEnv* jni_env,
14081 jthread thread);
14082 </example>
14083 See the individual events for the callback function definition.
14084 </description>
14085 </basetype>
14086 <basetype id="jniNativeInterface">
14087 <definition>typedef struct JNINativeInterface_ jniNativeInterface;</definition>
14088 <description>
14089 Typedef for the JNI function table <code>JNINativeInterface</code>
14090 defined in the
14091 <externallink id="jni/functions.html#interface-function-table">
14092 JNI Specification</externallink>.
14093 The JNI reference implementation defines this with an underscore.
14094 </description>
14095 </basetype>
14096 </basetypes>
14097
14098 </datasection>
14099
14100 <issuessection label="Issues">
14101 <intro id="suspendRequired" label="Resolved Issue: Suspend - Required or Automatic">
14102 JVMDI requires that the agent suspend threads before calling
14103 certain sensitive functions. JVMPI requires garbage collection to be
14104 disabled before calling certain sensitive functions.
14105 It was suggested that rather than have this requirement, that
14106 VM place itself in a suitable state before performing an
14107 operation. This makes considerable sense since each VM
14108 knows its requirements and can most easily arrange a
14109 safe state.
14110 <p/>
14111 The ability to externally suspend/resume threads will, of
14112 course, remain. The ability to enable/disable garbage collection will not.
14113 <p/>
14114 This issue is resolved--suspend will not
14115 be required. The spec has been updated to reflect this.
14116 </intro>
14117
14118 <intro id="stackSampling" label="Resolved Issue: Call Stack Sampling">
14119 There are a variety of approaches to sampling call stacks.
14120 The biggest bifurcation is between VM controlled and agent
14121 controlled.
14122 <p/>
14123 This issue is resolved--agent controlled
14124 sampling will be the approach.
14125 </intro>
14126
14127 <intro id="threadRepresentation" label="Resolved Issue: Thread Representation">
14128 JVMDI represents threads as jthread. JVMPI primarily
14129 uses JNIEnv* to represent threads.
14130 <p/>
14131 The Expert Group has chosen jthread as the representation
14132 for threads in <jvmti/>.
14133 JNIEnv* is sent by
14134 events since it is needed to JNI functions. JNIEnv, per the
14135 JNI spec, are not supposed to be used outside their thread.
14136 </intro>
14137
14138 <intro id="design" label="Resolved Issue: Method Representation">
14139 The JNI spec allows an implementation to depend on jclass/jmethodID
14140 pairs, rather than simply a jmethodID, to reference a method.
14141 JVMDI, for consistency, choose the same representation.
14142 JVMPI, however, specifies that a jmethodID alone maps to a
14143 method. Both of the Sun <tm>J2SE</tm> virtual machines (Classic and <tm>HotSpot</tm>) store
14144 pointers in jmethodIDs, and as a result, a jmethodID is sufficient.
14145 In fact, any JVM implementation that supports JVMPI must have
14146 such a representation.
14147 <jvmti/> will use jmethodID as a unique representation of a method
14148 (no jclass is used).
14149 There should be efficiency gains, particularly in
14150 functionality like stack dumping, to this representation.
14151 <p/>
14152 Note that fields were not used in JVMPI and that the access profile
14153 of fields differs from methods--for implementation efficiency
14154 reasons, a jclass/jfieldID pair will still be needed for field
14155 reference.
14156 </intro>
14157
14158 <intro id="localReferenceIssue" label="Resolved Issue: Local References">
14159 Functions return local references.
14160 </intro>
14161
14162 <intro id="frameRep" label="Resolved Issue: Representation of frames">
14163 In JVMDI, a frame ID is used to represent a frame. Problem with this
14164 is that a VM must track when a frame becomes invalid, a far better
14165 approach, and the one used in <jvmti/>, is to reference frames by depth.
14166 </intro>
14167
14168 <intro id="requiredCapabilities" label="Issue: Required Capabilities">
14169 Currently, having a required capabilities means that the functionality
14170 is optional. Capabilities are useful even for required functionality
14171 since they can inform the VM is needed set-up. Thus, there should be
14172 a set of capabilities that a conformant implementation must provide
14173 (if requested during Agent_OnLoad).
14174 </intro>
14175
14176 <intro id="taghint" label="Proposal: add tag hint function">
14177 A hint of the percentage of objects that will be tagged would
14178 help the VM pick a good implementation.
14179 </intro>
14180
14181 <intro id="moreMonitorQueries" label="Request: More Monitor Quires">
14182 How difficult or easy would be to extend the monitor_info category to include
14183 <pre>
14184 - current number of monitors
14185 - enumeration of monitors
14186 - enumeration of threads waiting on a given monitor
14187 </pre>
14188 The reason for my question is the fact that current get_monitor_info support
14189 requires the agent to specify a given thread to get the info which is probably
14190 OK in the profiling/debugging space, while in the monitoring space the agent
14191 could be watching the monitor list and then decide which thread to ask for
14192 the info. You might ask why is this important for monitoring .... I think it
14193 can aid in the detection/prediction of application contention caused by hot-locks.
14194 </intro>
14195 </issuessection>
14196
14197 <changehistory id="ChangeHistory" update="09/05/07">
14198 <intro>
14199 The <jvmti/> specification is an evolving document with major, minor,
14200 and micro version numbers.
14201 A released version of the specification is uniquely identified
14202 by its major and minor version.
14203 The functions, events, and capabilities in this specification
14204 indicate a "Since" value which is the major and minor version in
14205 which it was introduced.
14206 The version of the specification implemented by the VM can
14207 be retrieved at runtime with the <functionlink id="GetVersionNumber"/>
14208 function.
14209 </intro>
14210 <change date="14 Nov 2002">
14211 Converted to XML document.
14212 </change>
14213 <change date="14 Nov 2002">
14214 Elided heap dump functions (for now) since what was there
14215 was wrong.
14216 </change>
14217 <change date="18 Nov 2002">
14218 Added detail throughout.
14219 </change>
14220 <change date="18 Nov 2002">
14221 Changed JVMTI_THREAD_STATUS_RUNNING to JVMTI_THREAD_STATUS_RUNNABLE.
14222 </change>
14223 <change date="19 Nov 2002">
14224 Added AsyncGetStackTrace.
14225 </change>
14226 <change date="19 Nov 2002">
14227 Added jframeID return to GetStackTrace.
14228 </change>
14229 <change date="19 Nov 2002">
14230 Elided GetCurrentFrame and GetCallingFrame functions (for now) since what was there
14231 since they are redundant with GetStackTrace.
14232 </change>
14233 <change date="19 Nov 2002">
14234 Elided ClearAllBreakpoints since it has always been redundant.
14235 </change>
14236 <change date="19 Nov 2002">
14237 Added GetSystemProperties.
14238 </change>
14239 <change date="19 Nov 2002">
14240 Changed the thread local storage functions to use jthread.
14241 </change>
14242 <change date="20 Nov 2002">
14243 Added GetJLocationFormat.
14244 </change>
14245 <change date="22 Nov 2002">
14246 Added events and introductory text.
14247 </change>
14248 <change date="22 Nov 2002">
14249 Cross reference type and constant definitions.
14250 </change>
14251 <change date="24 Nov 2002">
14252 Added DTD.
14253 </change>
14254 <change date="24 Nov 2002">
14255 Added capabilities function section.
14256 </change>
14257 <change date="29 Nov 2002">
14258 Assign capabilities to each function and event.
14259 </change>
14260 <change date="29 Nov 2002">
14261 Add <internallink id="jniIntercept">JNI interception functions</internallink>.
14262 </change>
14263 <change date="30 Nov 2002">
14264 Auto generate SetEventNotificationMode capabilities.
14265 </change>
14266 <change date="30 Nov 2002">
14267 Add <eventlink id="VMObjectAlloc"></eventlink> event.
14268 </change>
14269 <change date="30 Nov 2002">
14270 Add <eventlink id="DynamicCodeGenerated"></eventlink> event.
14271 </change>
14272 <change date="30 Nov 2002">
14273 Add const to declarations.
14274 </change>
14275 <change date="30 Nov 2002">
14276 Change method exit and frame pop to send on exception.
14277 </change>
14278 <change date="1 Dec 2002">
14279 Add ForceGarbageCollection.
14280 </change>
14281 <change date="2 Dec 2002">
14282 Redo Xrun section; clarify GetStackTrace and add example;
14283 Fix width problems; use "agent" consistently.
14284 </change>
14285 <change date="8 Dec 2002">
14286 Remove previous start-up intro.
14287 Add <internallink id="environments"><jvmti/> Environments</internallink>
14288 section.
14289 </change>
14290 <change date="8 Dec 2002">
14291 Add <functionlink id="DisposeEnvironment"></functionlink>.
14292 </change>
14293 <change date="9 Dec 2002">
14294 Numerous minor updates.
14295 </change>
14296 <change date="15 Dec 2002">
14297 Add heap profiling functions added:
14298 get/set annotation, iterate live objects/heap.
14299 Add heap profiling functions place holder added:
14300 heap roots.
14301 Heap profiling event added: object free.
14302 Heap profiling event redesigned: vm object allocation.
14303 Heap profiling event placeholders added: garbage collection start/finish.
14304 Native method bind event added.
14305 </change>
14306 <change date="19 Dec 2002">
14307 Revamp suspend/resume functions.
14308 Add origin information with jvmdi tag.
14309 Misc fixes.
14310 </change>
14311 <change date="24 Dec 2002">
14312 Add semantics to types.
14313 </change>
14314 <change date="27 Dec 2002">
14315 Add local reference section.
14316 Autogenerate parameter descriptions from types.
14317 </change>
14318 <change date="28 Dec 2002">
14319 Document that RunAgentThread sends threadStart.
14320 </change>
14321 <change date="29 Dec 2002">
14322 Remove redundant local ref and dealloc warning.
14323 Convert GetRawMonitorName to allocated buffer.
14324 Add GenerateEvents.
14325 </change>
14326 <change date="30 Dec 2002">
14327 Make raw monitors a type and rename to "jrawMonitorID".
14328 </change>
14329 <change date="1 Jan 2003">
14330 Include origin information.
14331 Clean-up JVMDI issue references.
14332 Remove Deallocate warnings which are now automatically generated.
14333 </change>
14334 <change date="2 Jan 2003">
14335 Fix representation issues for jthread.
14336 </change>
14337 <change date="3 Jan 2003">
14338 Make capabilities buffered out to 64 bits - and do it automatically.
14339 </change>
14340 <change date="4 Jan 2003">
14341 Make constants which are enumeration into enum types.
14342 Parameters now of enum type.
14343 Clean-up and index type section.
14344 Replace remaining datadef entities with callback.
14345 </change>
14346 <change date="7 Jan 2003">
14347 Correct GenerateEvents description.
14348 More internal semantics work.
14349 </change>
14350 <change date="9 Jan 2003">
14351 Replace previous GetSystemProperties with two functions
14352 which use allocated information instead fixed.
14353 Add SetSystemProperty.
14354 More internal semantics work.
14355 </change>
14356 <change date="12 Jan 2003">
14357 Add varargs to end of SetEventNotificationMode.
14358 </change>
14359 <change date="20 Jan 2003">
14360 Finish fixing spec to reflect that alloc sizes are jlong.
14361 </change>
14362 <change date="22 Jan 2003">
14363 Allow NULL as RunAgentThread arg.
14364 </change>
14365 <change date="22 Jan 2003">
14366 Fixed names to standardized naming convention
14367 Removed AsyncGetStackTrace.
14368 </change>
14369 <change date="29 Jan 2003">
14370 Since we are using jthread, removed GetThread.
14371 </change>
14372 <change date="31 Jan 2003">
14373 Change GetFieldName to allow NULLs like GetMethodName.
14374 </change>
14375 <change date="29 Feb 2003" version="v40">
14376 Rewrite the introductory text, adding sections on
14377 start-up, environments and bytecode instrumentation.
14378 Change the command line arguments per EG discussions.
14379 Add an introduction to the capabilities section.
14380 Add the extension mechanism category and functions.
14381 Mark for deletion, but clarified anyhow, SuspendAllThreads.
14382 Rename IterateOverLiveObjects to IterateOverReachableObjects and
14383 change the text accordingly.
14384 Clarify IterateOverHeap.
14385 Clarify CompiledMethodLoad.
14386 Discuss prerequisite state for Calling Functions.
14387 Clarify SetAllocationHooks.
14388 Added issues ("To be resolved:") through-out.
14389 And so on...
14390 </change>
14391 <change date="6 Mar 2003" version="v41">
14392 Remove struct from the call to GetOwnedMonitorInfo.
14393 Automatically generate most error documentation, remove
14394 (rather broken) hand written error doc.
14395 Better describe capability use (empty initial set).
14396 Add min value to jint params.
14397 Remove the capability can_access_thread_local_storage.
14398 Rename error JVMTI_ERROR_NOT_IMPLEMENTED to JVMTI_ERROR_MUST_POSSESS_CAPABILITY;
14399 same for *NOT_IMPLEMENTED.
14400 Description fixes.
14401 </change>
14402 <change date="8 Mar 2003" version="v42">
14403 Rename GetClassSignature to GetClassName.
14404 Rename IterateOverClassObjects to IterateOverInstancesOfClass.
14405 Remove GetMaxStack (operand stack isn't used in <jvmti/>).
14406 Description fixes: define launch-time, remove native frame pop
14407 from PopFrame, and assorted clarifications.
14408 </change>
14409 <change date="8 Mar 2003" version="v43">
14410 Fix minor editing problem.
14411 </change>
14412 <change date="10 Mar 2003" version="v44">
14413 Add phase information.
14414 Remap (compact) event numbers.
14415 </change>
14416 <change date="11 Mar 2003" version="v45">
14417 More phase information - allow "any".
14418 Elide raw monitor queries and events.
14419 Minor description fixes.
14420 </change>
14421 <change date="12 Mar 2003" version="v46">
14422 Add GetPhase.
14423 Use "phase" through document.
14424 Elide GetRawMonitorName.
14425 Elide GetObjectMonitors.
14426 </change>
14427 <change date="12 Mar 2003" version="v47">
14428 Fixes from link, XML, and spell checking.
14429 Auto-generate the callback structure.
14430 </change>
14431 <change date="13 Mar 2003" version="v48">
14432 One character XML fix.
14433 </change>
14434 <change date="13 Mar 2003" version="v49">
14435 Change function parameter names to be consistent with
14436 event parameters (fooBarBaz becomes foo_bar_baz).
14437 </change>
14438 <change date="14 Mar 2003" version="v50">
14439 Fix broken link. Fix thread markers.
14440 </change>
14441 <change date="14 Mar 2003" version="v51">
14442 Change constants so they are under 128 to workaround
14443 compiler problems.
14444 </change>
14445 <change date="23 Mar 2003" version="v52">
14446 Overhaul capabilities. Separate GetStackTrace into
14447 GetStackTrace and GetStackFrames.
14448 </change>
14449 <change date="8 Apr 2003" version="v54">
14450 Use depth instead of jframeID to reference frames.
14451 Remove the now irrelevant GetCurrentFrame, GetCallerFrame and GetStackFrames.
14452 Remove frame arg from events.
14453 </change>
14454 <change date="9 Apr 2003" version="v55">
14455 Remove GetObjectWithAnnotation since tests show bufferred approach more efficient.
14456 Add missing annotation_count to GetObjectsWithAnnotations
14457 </change>
14458 <change date="10 Apr 2003" version="v56">
14459 Remove confusing parenthetical statement in GetObjectsWithAnnotations
14460 </change>
14461 <change date="13 Apr 2003" version="v58">
14462 Replace jclass/jmethodID representation of method with simply jmethodID;
14463 Pass JvmtiEnv* as first arg of every event; remove JNIEnv* where inappropriate.
14464 Replace can_access_frames with can_access_local_variables; remove from purely stack access.
14465 Use can_get_synthetic_attribute; fix description.
14466 Clarify that zero length arrays must be deallocated.
14467 Clarify RelinquishCapabilities.
14468 Generalize JVMTI_ERROR_VM_DEAD to JVMTI_ERROR_WRONG_PHASE.
14469 </change>
14470 <change date="27 Apr 2003" version="v59">
14471 Remove lingering indirect references to OBSOLETE_METHOD_ID.
14472 </change>
14473 <change date="4 May 2003" version="v60">
14474 Allow DestroyRawMonitor during OnLoad.
14475 </change>
14476 <change date="7 May 2003" version="v61">
14477 Added not monitor owner error return to DestroyRawMonitor.
14478 </change>
14479 <change date="13 May 2003" version="v62">
14480 Clarify semantics of raw monitors.
14481 Change flags on <code>GetThreadStatus</code>.
14482 <code>GetClassLoader</code> return NULL for the bootstrap class loader.
14483 Add <code>GetClassName</code> issue.
14484 Define local variable signature.
14485 Disallow zero in annotations array of <code>GetObjectsWithAnnotations</code>.
14486 Remove over specification in <code>GetObjectsWithAnnotations</code>.
14487 Elide <code>SetAllocationHooks</code>.
14488 Elide <code>SuspendAllThreads</code>.
14489 </change>
14490 <change date="14 May 2003" version="v63">
14491 Define the data type <code>jvmtiEventCallbacks</code>.
14492 Zero length allocations return NULL.
14493 Keep SetAllocationHooks in JVMDI, but remove from <jvmti/>.
14494 Add JVMTI_THREAD_STATUS_FLAG_INTERRUPTED.
14495 </change>
14496 <change date="15 May 2003" version="v64">
14497 Better wording, per review.
14498 </change>
14499 <change date="15 May 2003" version="v65">
14500 First Alpha.
14501 Make jmethodID and jfieldID unique, jclass not used.
14502 </change>
14503 <change date="27 May 2003" version="v66">
14504 Fix minor XSLT errors.
14505 </change>
14506 <change date="13 June 2003" version="v67">
14507 Undo making jfieldID unique (jmethodID still is).
14508 </change>
14509 <change date="17 June 2003" version="v68">
14510 Changes per June 11th Expert Group meeting --
14511 Overhaul Heap functionality: single callback,
14512 remove GetHeapRoots, add reachable iterators,
14513 and rename "annotation" to "tag".
14514 NULL thread parameter on most functions is current
14515 thread.
14516 Add timers.
14517 Remove ForceExit.
14518 Add GetEnvironmentLocalStorage.
14519 Add verbose flag and event.
14520 Add AddToBootstrapClassLoaderSearch.
14521 Update ClassFileLoadHook.
14522 </change>
14523 <change date="18 June 2003" version="v69">
14524 Clean up issues sections.
14525 Rename GetClassName back to GetClassSignature and
14526 fix description.
14527 Add generic signature to GetClassSignature,
14528 GetFieldSignature, GetMethodSignature, and
14529 GetLocalVariableTable.
14530 Elide EstimateCostOfCapabilities.
14531 Clarify that the system property functions operate
14532 on the VM view of system properties.
14533 Clarify Agent_OnLoad.
14534 Remove "const" from JNIEnv* in events.
14535 Add metadata accessors.
14536 </change>
14537 <change date="18 June 2003" version="v70">
14538 Add start_depth to GetStackTrace.
14539 Move system properties to a new category.
14540 Add GetObjectSize.
14541 Remove "X" from command line flags.
14542 XML, HTML, and spell check corrections.
14543 </change>
14544 <change date="19 June 2003" version="v71">
14545 Fix JVMTI_HEAP_ROOT_THREAD to be 6.
14546 Make each synopsis match the function name.
14547 Fix unclear wording.
14548 </change>
14549 <change date="26 June 2003" version="v72">
14550 SetThreadLocalStorage and SetEnvironmentLocalStorage should allow value
14551 to be set to NULL.
14552 NotifyFramePop, GetFrameLocationm and all the local variable operations
14553 needed to have their wording about frames fixed.
14554 Grammar and clarity need to be fixed throughout.
14555 Capitalization and puntuation need to be consistent.
14556 Need micro version number and masks for accessing major, minor, and micro.
14557 The error code lists should indicate which must be returned by
14558 an implementation.
14559 The command line properties should be visible in the properties functions.
14560 Disallow popping from the current thread.
14561 Allow implementations to return opaque frame error when they cannot pop.
14562 The NativeMethodBind event should be sent during any phase.
14563 The DynamicCodeGenerated event should be sent during any phase.
14564 The following functions should be allowed to operate before VMInit:
14565 Set/GetEnvironmentLocalStorage
14566 GetMethodDeclaringClass
14567 GetClassSignature
14568 GetClassModifiers
14569 IsInterface
14570 IsArrayClass
14571 GetMethodName
14572 GetMethodModifiers
14573 GetMaxLocals
14574 GetArgumentsSize
14575 GetLineNumberTable
14576 GetMethodLocation
14577 IsMethodNative
14578 IsMethodSynthetic.
14579 Other changes (to XSL):
14580 Argument description should show asterisk after not before pointers.
14581 NotifyFramePop, GetFrameLocationm and all the local variable operations
14582 should hsve the NO_MORE_FRAMES error added.
14583 Not alive threads should have a different error return than invalid thread.
14584 </change>
14585 <change date="7 July 2003" version="v73">
14586 VerboseOutput event was missing message parameter.
14587 Minor fix-ups.
14588 </change>
14589 <change date="14 July 2003" version="v74">
14590 Technical Publications Department corrections.
14591 Allow thread and environment local storage to be set to NULL.
14592 </change>
14593 <change date="23 July 2003" version="v75">
14594 Use new Agent_OnLoad rather than overloaded JVM_OnLoad.
14595 Add JNICALL to callbacks (XSL).
14596 Document JNICALL requirement for both events and callbacks (XSL).
14597 Restrict RedefineClasses to methods and attributes.
14598 Elide the VerboseOutput event.
14599 VMObjectAlloc: restrict when event is sent and remove method parameter.
14600 Finish loose ends from Tech Pubs edit.
14601 </change>
14602 <change date="24 July 2003" version="v76">
14603 Change ClassFileLoadHook event to send the class instead of a boolean of redefine.
14604 </change>
14605 <change date="24 July 2003" version="v77">
14606 XML fixes.
14607 Minor text clarifications and corrections.
14608 </change>
14609 <change date="24 July 2003" version="v78">
14610 Remove GetExceptionHandlerTable and GetThrownExceptions from <jvmti/>.
14611 Clarify that stack frames are JVM Spec frames.
14612 Split can_get_source_info into can_get_source_file_name, can_get_line_numbers,
14613 and can_get_source_debug_extension.
14614 PopFrame cannot have a native calling method.
14615 Removed incorrect statement in GetClassloaderClasses
14616 (see <vmspec chapter="4.4"/>).
14617 </change>
14618 <change date="24 July 2003" version="v79">
14619 XML and text fixes.
14620 Move stack frame description into Stack Frame category.
14621 </change>
14622 <change date="26 July 2003" version="v80">
14623 Allow NULL (means bootstrap loader) for GetClassloaderClasses.
14624 Add new heap reference kinds for references from classes.
14625 Add timer information struct and query functions.
14626 Add AvailableProcessors.
14627 Rename GetOtherThreadCpuTime to GetThreadCpuTime.
14628 Explicitly add JVMTI_ERROR_INVALID_THREAD and JVMTI_ERROR_THREAD_NOT_ALIVE
14629 to SetEventNotification mode.
14630 Add initial thread to the VM_INIT event.
14631 Remove platform assumptions from AddToBootstrapClassLoaderSearch.
14632 </change>
14633 <change date="26 July 2003" version="v81">
14634 Grammar and clarity changes per review.
14635 </change>
14636 <change date="27 July 2003" version="v82">
14637 More grammar and clarity changes per review.
14638 Add Agent_OnUnload.
14639 </change>
14640 <change date="28 July 2003" version="v83">
14641 Change return type of Agent_OnUnload to void.
14642 </change>
14643 <change date="28 July 2003" version="v84">
14644 Rename JVMTI_REFERENCE_ARRAY to JVMTI_REFERENCE_ARRAY_ELEMENT.
14645 </change>
14646 <change date="28 July 2003" version="v85">
14647 Steal java.lang.Runtime.availableProcessors() wording for
14648 AvailableProcessors().
14649 Guarantee that zero will never be an event ID.
14650 Remove some issues which are no longer issues.
14651 Per review, rename and more completely document the timer
14652 information functions.
14653 </change>
14654 <change date="29 July 2003" version="v86">
14655 Non-spec visible change to XML controlled implementation:
14656 SetThreadLocalStorage must run in VM mode.
14657 </change>
14658 <change date="5 August 2003" version="0.1.87">
14659 Add GetErrorName.
14660 Add varargs warning to jvmtiExtensionEvent.
14661 Remove "const" on the jvmtiEnv* of jvmtiExtensionEvent.
14662 Remove unused can_get_exception_info capability.
14663 Pass jvmtiEnv* and JNIEnv* to the jvmtiStartFunction.
14664 Fix jvmtiExtensionFunctionInfo.func declared type.
14665 Extension function returns error code.
14666 Use new version numbering.
14667 </change>
14668 <change date="5 August 2003" version="0.2.88">
14669 Remove the ClassUnload event.
14670 </change>
14671 <change date="8 August 2003" version="0.2.89">
14672 Heap reference iterator callbacks return an enum that
14673 allows outgoing object references to be ignored.
14674 Allow JNIEnv as a param type to extension events/functions.
14675 </change>
14676 <change date="15 August 2003" version="0.2.90">
14677 Fix a typo.
14678 </change>
14679 <change date="2 September 2003" version="0.2.91">
14680 Remove all metadata functions: GetClassMetadata,
14681 GetFieldMetadata, and GetMethodMetadata.
14682 </change>
14683 <change date="1 October 2003" version="0.2.92">
14684 Mark the functions Allocate. Deallocate, RawMonitor*,
14685 SetEnvironmentLocalStorage, and GetEnvironmentLocalStorage
14686 as safe for use in heap callbacks and GC events.
14687 </change>
14688 <change date="24 November 2003" version="0.2.93">
14689 Add pass through opaque user data pointer to heap iterate
14690 functions and callbacks.
14691 In the CompiledMethodUnload event, send the code address.
14692 Add GarbageCollectionOccurred event.
14693 Add constant pool reference kind.
14694 Mark the functions CreateRawMonitor and DestroyRawMonitor
14695 as safe for use in heap callbacks and GC events.
14696 Clarify: VMDeath, GetCurrentThreadCpuTimerInfo,
14697 GetThreadCpuTimerInfo, IterateOverReachableObjects,
14698 IterateOverObjectsReachableFromObject, GetTime and
14699 JVMTI_ERROR_NULL_POINTER.
14700 Add missing errors to: GenerateEvents and
14701 AddToBootstrapClassLoaderSearch.
14702 Fix description of ClassFileLoadHook name parameter.
14703 In heap callbacks and GC/ObjectFree events, specify
14704 that only explicitly allowed functions can be called.
14705 Allow GetCurrentThreadCpuTimerInfo, GetCurrentThreadCpuTime,
14706 GetTimerInfo, and GetTime during callback.
14707 Allow calling SetTag/GetTag during the onload phase.
14708 SetEventNotificationMode, add: error attempted inappropriate
14709 thread level control.
14710 Remove jvmtiExceptionHandlerEntry.
14711 Fix handling of native methods on the stack --
14712 location_ptr param of GetFrameLocation, remove
14713 JVMTI_ERROR_OPAQUE_FRAME from GetFrameLocation,
14714 jvmtiFrameInfo.location, and jlocation.
14715 Remove typo (from JVMPI) implying that the MonitorWaited
14716 event is sent on sleep.
14717 </change>
14718 <change date="25 November 2003" version="0.2.94">
14719 Clarifications and typos.
14720 </change>
14721 <change date="3 December 2003" version="0.2.95">
14722 Allow NULL user_data in heap iterators.
14723 </change>
14724 <change date="28 January 2004" version="0.2.97">
14725 Add GetThreadState, deprecate GetThreadStatus.
14726 </change>
14727 <change date="29 January 2004" version="0.2.98">
14728 INVALID_SLOT and TYPE_MISMATCH errors should be optional.
14729 </change>
14730 <change date="12 February 2004" version="0.2.102">
14731 Remove MonitorContendedExit.
14732 Added JNIEnv parameter to VMObjectAlloc.
14733 Clarified definition of class_tag and referrer_index
14734 parameters to heap callbacks.
14735 </change>
14736 <change date="16 Febuary 2004" version="0.2.103">
14737 Document JAVA_TOOL_OPTIONS.
14738 </change>
14739 <change date="17 Febuary 2004" version="0.2.105">
14740 Divide start phase into primordial and start.
14741 Add VMStart event
14742 Change phase associations of functions and events.
14743 </change>
14744 <change date="18 Febuary 2004" version="0.3.6">
14745 Elide deprecated GetThreadStatus.
14746 Bump minor version, subtract 100 from micro version
14747 </change>
14748 <change date="18 Febuary 2004" version="0.3.7">
14749 Document that timer nanosecond values are unsigned.
14750 Clarify text having to do with native methods.
14751 </change>
14752 <change date="19 Febuary 2004" version="0.3.8">
14753 Fix typos.
14754 Remove elided deprecated GetThreadStatus.
14755 </change>
14756 <change date="23 Febuary 2004" version="0.3.9">
14757 Require NotifyFramePop to act on suspended threads.
14758 </change>
14759 <change date="24 Febuary 2004" version="0.3.10">
14760 Add capabilities
14761 (<internallink id="jvmtiCapabilities.can_redefine_any_class"
14762 ><code>can_redefine_any_class</code></internallink>
14763 and
14764 <internallink id="jvmtiCapabilities.can_generate_all_class_hook_events"
14765 ><code>can_generate_all_class_hook_events</code></internallink>)
14766 and an error (<errorlink id="JVMTI_ERROR_UNMODIFIABLE_CLASS"></errorlink>)
14767 which allow some classes to be unmodifiable.
14768 </change>
14769 <change date="28 Febuary 2004" version="0.3.11">
14770 Add JVMTI_ERROR_MUST_POSSESS_CAPABILITY to SetEventNotificationMode.
14771 </change>
14772 <change date="8 March 2004" version="0.3.12">
14773 Clarified CompiledMethodUnload so that it is clear the event
14774 may be posted after the class has been unloaded.
14775 </change>
14776 <change date="5 March 2004" version="0.3.13">
14777 Change the size parameter of VMObjectAlloc to jlong to match GetObjectSize.
14778 </change>
14779 <change date="13 March 2004" version="0.3.14">
14780 Added guideline for the use of the JNI FindClass function in event
14781 callback functions.
14782 </change>
14783 <change date="15 March 2004" version="0.3.15">
14784 Add GetAllStackTraces and GetThreadListStackTraces.
14785 </change>
14786 <change date="19 March 2004" version="0.3.16">
14787 ClassLoad and ClassPrepare events can be posted during start phase.
14788 </change>
14789 <change date="25 March 2004" version="0.3.17">
14790 Add JVMTI_ERROR_NATIVE_METHOD to GetLineNumberTable, GetLocalVariableTable,
14791 GetMaxLocals, GetArgumentsSize, GetMethodLocation, GetBytecodes.
14792 </change>
14793 <change date="29 March 2004" version="0.3.18">
14794 Return the timer kind in the timer information structure.
14795 </change>
14796 <change date="31 March 2004" version="0.3.19">
14797 Spec clarifications:
14798 JVMTI_THREAD_STATE_IN_NATIVE might not include JNI or <jvmti/>.
14799 ForceGarbageCollection does not run finalizers.
14800 The context of the specification is the Java platform.
14801 Warn about early instrumentation.
14802 </change>
14803 <change date="1 April 2004" version="0.3.20">
14804 Refinements to the above clarifications and
14805 Clarify that an error returned by Agent_OnLoad terminates the VM.
14806 </change>
14807 <change date="1 April 2004" version="0.3.21">
14808 Array class creation does not generate a class load event.
14809 </change>
14810 <change date="7 April 2004" version="0.3.22">
14811 Align thread state hierarchy more closely with java.lang.Thread.State.
14812 </change>
14813 <change date="12 April 2004" version="0.3.23">
14814 Clarify the documentation of thread state.
14815 </change>
14816 <change date="19 April 2004" version="0.3.24">
14817 Remove GarbageCollectionOccurred event -- can be done by agent.
14818 </change>
14819 <change date="22 April 2004" version="0.3.25">
14820 Define "command-line option".
14821 </change>
14822 <change date="29 April 2004" version="0.3.26">
14823 Describe the intended use of bytecode instrumentation.
14824 Fix description of extension event first parameter.
14825 </change>
14826 <change date="30 April 2004" version="0.3.27">
14827 Clarification and typos.
14828 </change>
14829 <change date="18 May 2004" version="0.3.28">
14830 Remove DataDumpRequest event.
14831 </change>
14832 <change date="18 May 2004" version="0.3.29">
14833 Clarify RawMonitorWait with zero timeout.
14834 Clarify thread state after RunAgentThread.
14835 </change>
14836 <change date="24 May 2004" version="0.3.30">
14837 Clean-up: fix bad/old links, etc.
14838 </change>
14839 <change date="30 May 2004" version="0.3.31">
14840 Clarifications including:
14841 All character strings are modified UTF-8.
14842 Agent thread visibiity.
14843 Meaning of obsolete method version.
14844 Thread invoking heap callbacks,
14845 </change>
14846 <change date="1 June 2004" version="1.0.32">
14847 Bump major.minor version numbers to "1.0".
14848 </change>
14849 <change date="2 June 2004" version="1.0.33">
14850 Clarify interaction between ForceGarbageCollection
14851 and ObjectFree.
14852 </change>
14853 <change date="6 June 2004" version="1.0.34">
14854 Restrict AddToBootstrapClassLoaderSearch and
14855 SetSystemProperty to the OnLoad phase only.
14856 </change>
14857 <change date="11 June 2004" version="1.0.35">
14858 Fix typo in SetTag.
14859 </change>
14860 <change date="18 June 2004" version="1.0.36">
14861 Fix trademarks.
14862 Add missing parameter in example GetThreadState usage.
14863 </change>
14864 <change date="4 August 2004" version="1.0.37">
14865 Copyright updates.
14866 </change>
14867 <change date="5 November 2004" version="1.0.38">
14868 Add missing function table layout.
14869 Add missing description of C++ member function format of functions.
14870 Clarify that name in CFLH can be NULL.
14871 Released as part of <tm>J2SE</tm> 5.0.
14872 </change>
14873 <change date="24 April 2005" version="1.1.47">
14874 Bump major.minor version numbers to "1.1".
14875 Add ForceEarlyReturn* functions.
14876 Add GetOwnedMonitorStackDepthInfo function.
14877 Add GetCurrentThread function.
14878 Add "since" version marker.
14879 Add AddToSystemClassLoaderSearch.
14880 Allow AddToBootstrapClassLoaderSearch be used in live phase.
14881 Fix historic rubbish in the descriptions of the heap_object_callback
14882 parameter of IterateOverHeap and IterateOverInstancesOfClass functions;
14883 disallow NULL for this parameter.
14884 Clarify, correct and make consistent: wording about current thread,
14885 opaque frames and insufficient number of frames in PopFrame.
14886 Consistently use "current frame" rather than "topmost".
14887 Clarify the JVMTI_ERROR_TYPE_MISMATCH errors in GetLocal* and SetLocal*
14888 by making them compatible with those in ForceEarlyReturn*.
14889 Many other clarifications and wording clean ups.
14890 </change>
14891 <change date="25 April 2005" version="1.1.48">
14892 Add GetConstantPool.
14893 Switch references to the first edition of the VM Spec, to the seconds edition.
14894 </change>
14895 <change date="26 April 2005" version="1.1.49">
14896 Clarify minor/major version order in GetConstantPool.
14897 </change>
14898 <change date="26 April 2005" version="1.1.50">
14899 Add SetNativeMethodPrefix and SetNativeMethodPrefixes.
14900 Reassign GetOwnedMonitorStackDepthInfo to position 153.
14901 Break out Class Loader Search in its own documentation category.
14902 Deal with overly long lines in XML source.
14903 </change>
14904 <change date="29 April 2005" version="1.1.51">
14905 Allow agents be started in the live phase.
14906 Added paragraph about deploying agents.
14907 </change>
14908 <change date="30 April 2005" version="1.1.52">
14909 Add specification description to SetNativeMethodPrefix(es).
14910 Better define the conditions on GetConstantPool.
14911 </change>
14912 <change date="30 April 2005" version="1.1.53">
14913 Break out the GetClassVersionNumber function from GetConstantPool.
14914 Clean-up the references to the VM Spec.
14915 </change>
14916 <change date="1 May 2005" version="1.1.54">
14917 Allow SetNativeMethodPrefix(es) in any phase.
14918 Add clarifications about the impact of redefinition on GetConstantPool.
14919 </change>
14920 <change date="2 May 2005" version="1.1.56">
14921 Various clarifications to SetNativeMethodPrefix(es).
14922 </change>
14923 <change date="2 May 2005" version="1.1.57">
14924 Add missing performance warning to the method entry event.
14925 </change>
14926 <change date="5 May 2005" version="1.1.58">
14927 Remove internal JVMDI support.
14928 </change>
14929 <change date="8 May 2005" version="1.1.59">
14930 Add <functionlink id="RetransformClasses"/>.
14931 Revamp the bytecode instrumentation documentation.
14932 Change <functionlink id="IsMethodObsolete"/> to no longer
14933 require the can_redefine_classes capability.
14934 </change>
14935 <change date="11 May 2005" version="1.1.63">
14936 Clarifications for retransformation.
14937 </change>
14938 <change date="11 May 2005" version="1.1.64">
14939 Clarifications for retransformation, per review.
14940 Lock "retransformation (in)capable" at class load enable time.
14941 </change>
14942 <change date="4 June 2005" version="1.1.67">
14943 Add new heap functionity which supports reporting primitive values,
14944 allows setting the referrer tag, and has more powerful filtering:
14945 FollowReferences, IterateThroughHeap, and their associated
14946 callbacks, structs, enums, and constants.
14947 </change>
14948 <change date="4 June 2005" version="1.1.68">
14949 Clarification.
14950 </change>
14951 <change date="6 June 2005" version="1.1.69">
14952 FollowReferences, IterateThroughHeap: Put callbacks in a struct;
14953 Add missing error codes; reduce bits in the visit control flags.
14954 </change>
14955 <change date="14 June 2005" version="1.1.70">
14956 More on new heap functionity: spec clean-up per review.
14957 </change>
14958 <change date="15 June 2005" version="1.1.71">
14959 More on new heap functionity: Rename old heap section to Heap (1.0).
14960 </change>
14961 <change date="21 June 2005" version="1.1.72">
14962 Fix typos.
14963 </change>
14964 <change date="27 June 2005" version="1.1.73">
14965 Make referrer info structure a union.
14966 </change>
14967 <change date="9 September 2005" version="1.1.74">
14968 In new heap functions:
14969 Add missing superclass reference kind.
14970 Use a single scheme for computing field indexes.
14971 Remove outdated references to struct based referrer info.
14972 </change>
14973 <change date="12 September 2005" version="1.1.75">
14974 Don't callback during FollowReferences on frivolous java.lang.Object superclass.
14975 </change>
14976 <change date="13 September 2005" version="1.1.76">
14977 In string primitive callback, length now Unicode length.
14978 In array and string primitive callbacks, value now "const".
14979 Note possible compiler impacts on setting JNI function table.
14980 </change>
14981 <change date="13 September 2005" version="1.1.77">
14982 GetClassVersionNumbers() and GetConstantPool() should return
14983 error on array or primitive class.
14984 </change>
14985 <change date="14 September 2005" version="1.1.78">
14986 Grammar fixes.
14987 </change>
14988 <change date="26 September 2005" version="1.1.79">
14989 Add IsModifiableClass query.
14990 </change>
14991 <change date="9 February 2006" version="1.1.81">
14992 Add referrer_class_tag parameter to jvmtiHeapReferenceCallback.
14993 </change>
14994 <change date="13 February 2006" version="1.1.82">
14995 Doc fixes: update can_redefine_any_class to include retransform.
14996 Clarify that exception events cover all Throwables.
14997 In GetStackTrace, no test is done for start_depth too big if start_depth is zero,
14998 Clarify fields reported in Primitive Field Callback -- static vs instance.
14999 Repair confusing names of heap types, including callback names.
15000 Require consistent usage of stack depth in the face of thread launch methods.
15001 Note incompatibility of <jvmti/> memory management with other systems.
15002 </change>
15003 <change date="14 February 2006" version="1.1.85">
15004 Fix typos and missing renames.
15005 </change>
15006 <change date="13 March 2006" version="1.1.86">
15007 Clarify that jmethodIDs and jfieldIDs can be saved.
15008 Clarify that Iterate Over Instances Of Class includes subclasses.
15009 </change>
15010 <change date="14 March 2006" version="1.1.87">
15011 Better phrasing.
15012 </change>
15013 <change date="16 March 2006" version="1.1.88">
15014 Match the referrer_index for static fields in Object Reference Callback
15015 with the Reference Implementation (and all other known implementations);
15016 that is, make it match the definition for instance fields.
15017 In GetThreadListStackTraces, add JVMTI_ERROR_INVALID_THREAD to cover
15018 an invalid thread in the list; and specify that not started threads
15019 return empty stacks.
15020 </change>
15021 <change date="17 March 2006" version="1.1.89">
15022 Typo.
15023 </change>
15024 <change date="25 March 2006" version="1.1.90">
15025 Typo.
15026 </change>
15027 <change date="6 April 2006" version="1.1.91">
15028 Remove restrictions on AddToBootstrapClassLoaderSearch and
15029 AddToSystemClassLoaderSearch.
15030 </change>
15031 <change date="1 May 2006" version="1.1.93">
15032 Changed spec to return -1 for monitor stack depth for the
15033 implementation which can not determine stack depth.
15034 </change>
15035 <change date="3 May 2006" version="1.1.94">
15036 Corrections for readability and accuracy courtesy of Alan Pratt of IBM.
15037 List the object relationships reported in FollowReferences.
15038 </change>
15039 <change date="5 May 2006" version="1.1.95">
15040 Clarify the object relationships reported in FollowReferences.
15041 </change>
15042 <change date="28 June 2006" version="1.1.98">
15043 Clarify DisposeEnvironment; add warning.
15044 Fix typos in SetLocalXXX "retrieve" => "set".
15045 Clarify that native method prefixes must remain set while used.
15046 Clarify that exactly one Agent_OnXXX is called per agent.
15047 Clarify that library loading is independent from start-up.
15048 Remove ambiguous reference to Agent_OnLoad in the Agent_OnUnload spec.
15049 </change>
15050 <change date="31 July 2006" version="1.1.99">
15051 Clarify the interaction between functions and exceptions.
15052 Clarify and give examples of field indices.
15053 Remove confusing "That is" sentence from MonitorWait and MonitorWaited events.
15054 Update links to point to Java 6.
15055 </change>
15056 <change date="6 August 2006" version="1.1.102">
15057 Add ResourceExhaustedEvent.
15058 </change>
15059 <change date="11 October 2012" version="1.2.2">
15060 Fixed the "HTTP" and "Missing Anchor" errors reported by the LinkCheck tool.
15061 </change>
15062 <change date="19 June 2013" version="1.2.3">
15063 Added support for statically linked agents.
15064 </change>
15065 <change date="13 October 2016" version="9.0.0">
15066 Support for modules:
15067 - The majorversion is 9 now
15068 - The ClassFileLoadHook events are not sent during the primordial phase anymore.
15069 - Allow CompiledMethodLoad events at start phase
15070 - Add new capabilities:
15071 - can_generate_early_vmstart
15072 - can_generate_early_class_hook_events
15073 - Add new functions:
15074 - GetAllModules
15075 - AddModuleReads, AddModuleExports, AddModuleOpens, AddModuleUses, AddModuleProvides
15076 - IsModifiableModule
15077 Clarified can_redefine_any_classes, can_retransform_any_classes and IsModifiableClass API to
15078 disallow some implementation defined classes.
15079 </change>
15080 <change date="12 February 2017" version="9.0.0">
15081 Minor update for GetCurrentThread function:
15082 - The function may return NULL in the start phase if the
15083 can_generate_early_vmstart capability is enabled.
15084 </change>
15085 </changehistory>
15086
15087 </specification>
15088 <!-- Keep this comment at the end of the file
15089 Local variables:
15090 mode: sgml
15091 sgml-omittag:t
15092 sgml-shorttag:t
15093 sgml-namecase-general:t
15094 sgml-general-insert-case:lower
15095 sgml-minimize-attributes:nil
15096 sgml-always-quote-attributes:t
15097 sgml-indent-step:2
15098 sgml-indent-data:t
15099 sgml-parent-document:nil
15100 sgml-exposed-tags:nil
15101 sgml-local-catalogs:nil
15102 sgml-local-ecat-files:nil
15103 End:
15104 -->