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26
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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="http://docs.oracle.com/javase/7/docs/technotes/guides/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="entry point" 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="http://docs.oracle.com/javase/7/docs/technotes/guides/jni/spec/invocation.html#GetEnv"><code>GetEnv</code></externallink>.
769 See <internallink id="jvmtiEnvAccess">Accessing <jvmti/> Functions</internallink>
770 for more details on the creation and use of
771 <jvmti/> environments.
772 Typically, <jvmti/> environments are created by calling <code>GetEnv</code> from
773 <internallink id="onload"><code>Agent_OnLoad</code></internallink>.
774 </intro>
775
776 <intro id="bci" label="Bytecode Instrumentation">
777 This interface does not include some events that one might expect in an interface with
778 profiling support. Some examples include object allocation events and full speed
779 method enter and exit events. The interface instead provides support for
780 <i>bytecode instrumentation</i>, the ability to alter the Java virtual machine
781 bytecode instructions which comprise the target program. Typically, these alterations
782 are to add "events" to the code of a method - for example, to add, at the beginning of a method,
783 a call to <code>MyProfiler.methodEntered()</code>.
784 Since the changes are purely additive, they do not modify application
785 state or behavior.
786 Because the inserted agent code is standard bytecodes, the VM can run at full speed,
787 optimizing not only the target program but also the instrumentation. If the
788 instrumentation does not involve switching from bytecode execution, no expensive
789 state transitions are needed. The result is high performance events.
790 This approach also provides complete control to the agent: instrumentation can be
791 restricted to "interesting" portions of the code (e.g., the end user's code) and
792 can be conditional. Instrumentation can run entirely in Java programming language
793 code or can call into the native agent. Instrumentation can simply maintain
794 counters or can statistically sample events.
795 <p/>
796 Instrumentation can be inserted in one of three ways:
797 <ul>
798 <li>
799 Static Instrumentation: The class file is instrumented before it
800 is loaded into the VM - for example, by creating a duplicate directory of
801 <code>*.class</code> files which have been modified to add the instrumentation.
802 This method is extremely awkward and, in general, an agent cannot know
803 the origin of the class files which will be loaded.
804 </li>
805 <li>
806 Load-Time Instrumentation: When a class file is loaded by the VM, the raw
807 bytes of the class file are sent for instrumentation to the agent.
808 The <eventlink id="ClassFileLoadHook"/>
809 event, triggered by the class load,
810 provides this functionality. This mechanism provides efficient
811 and complete access to one-time instrumentation.
812 </li>
813 <li>
814 Dynamic Instrumentation: A class which is already loaded (and possibly
815 even running) is modified. This optional feature is provided by the
816 <eventlink id="ClassFileLoadHook"/> event, triggered by calling the
817 <functionlink id="RetransformClasses"/> function.
818 Classes can be modified multiple times and can be returned to their
819 original state.
820 The mechanism allows instrumentation which changes during the
821 course of execution.
822 </li>
823 </ul>
824 <p/>
825 The class modification functionality provided in this interface
826 is intended to provide a mechanism for instrumentation
827 (the <eventlink id="ClassFileLoadHook"/> event
828 and the <functionlink id="RetransformClasses"/> function)
829 and, during development, for fix-and-continue debugging
830 (the <functionlink id="RedefineClasses"/> function).
831 <p/>
832 Care must be taken to avoid perturbing dependencies, especially when
833 instrumenting core classes. For example, an approach to getting notification
834 of every object allocation is to instrument the constructor on
835 <code>Object</code>. Assuming that the constructor is initially
836 empty, the constructor could be changed to:
837 <example>
838 public Object() {
839 MyProfiler.allocationTracker(this);
840 }
841 </example>
842 However, if this change was made using the
843 <eventlink id="ClassFileLoadHook"/>
844 event then this might impact a typical VM as follows:
845 the first created object will call the constructor causing a class load of
846 <code>MyProfiler</code>; which will then cause
847 object creation, and since <code>MyProfiler</code> isn't loaded yet,
848 infinite recursion; resulting in a stack overflow. A refinement of this
849 would be to delay invoking the tracking method until a safe time. For
850 example, <code>trackAllocations</code> could be set in the
851 handler for the <code>VMInit</code> event.
852 <example>
853 static boolean trackAllocations = false;
854
855 public Object() {
856 if (trackAllocations) {
857 MyProfiler.allocationTracker(this);
858 }
859 }
860 </example>
861 <p/>
862 The <functionlink id="SetNativeMethodPrefix"/> allows native methods
863 to be instrumented by the use of wrapper methods.
864 </intro>
865
866 <intro id="bcimodules" label="Bytecode Instrumentation of code in modules">
867 Agents that instrument code in named modules may need to arrange for those
868 modules to read other modules. If code is instrumented to invoke a method
869 in a support class in another module, then the module of the instrumented
870 code should read the module of the supporting class. Furthermore, the
871 supporting class will only be accessible to the instrumented code if
872 it is <code>public</code> and in a package that is exported by its module.
873 Agents can use the JNI functions <code>CanReadModule</code> and
874 <code>AddModuleReads</code> to test and update a module to read another.
875 <p/>
876 As an aid to agents that deploy supporting classes on the search path of
877 the bootstrap class loader, or the search path of the class loader that
878 loads the main class, the Java virtual machine arranges for the module
879 of classes transformed by the <eventlink id="ClassFileLoadHook"/> event to
880 read the unnamed module of both class loaders.
881 </intro>
882
883 <intro id="mUTF" label="Modified UTF-8 String Encoding">
884 <jvmti/> uses modified UTF-8 to encode character strings.
885 This is the same encoding used by JNI.
886 Modified UTF-8 differs
887 from standard UTF-8 in the representation of supplementary characters
888 and of the null character. See the
889 <externallink id="http://docs.oracle.com/javase/7/docs/technotes/guides/jni/spec/types.html#wp16542">
890 Modified UTF-8 Strings</externallink>
891 section of the JNI specification for details.
892 </intro>
893
894 <intro id="context" label="Specification Context">
895 Since this interface provides access to the state of applications running in the
896 Java virtual machine;
897 terminology refers to the Java platform and not the native
898 platform (unless stated otherwise). For example:
899 <ul>
900 <li>"thread" means Java programming language thread.</li>
901 <li>"stack frame" means Java virtual machine stack frame.</li>
902 <li>"class" means Java programming language class.</li>
903 <li>"heap" means Java virtual machine heap.</li>
904 <li>"monitor" means Java programming language object monitor.</li>
905 </ul>
906 <p/>
907 Sun, Sun Microsystems, the Sun logo, Java, and JVM
908 are trademarks or registered trademarks of Oracle
909 and/or its affiliates, in the U.S. and other countries.
910 </intro>
911
912
913 <functionsection label="Functions">
914 <intro id="jvmtiEnvAccess" label="Accessing Functions">
915 Native code accesses <jvmti/> features
916 by calling <jvmti/> functions.
917 Access to <jvmti/> functions is by use of an interface pointer
918 in the same manner as
919 <externallink id="http://docs.oracle.com/javase/7/docs/technotes/guides/jni/spec/design.html">Java
920 Native Interface (JNI) functions</externallink> are accessed.
921 The <jvmti/> interface pointer is called the
922 <i>environment pointer</i>.
923 <p/>
924 An environment pointer is a pointer to an environment and has
925 the type <code>jvmtiEnv*</code>.
926 An environment has information about its <jvmti/> connection.
927 The first value in the environment is a pointer to the function table.
928 The function table is an array of pointers to <jvmti/> functions.
929 Every function pointer is at a predefined offset inside the
930 array.
931 <p/>
932 When used from the C language:
933 double indirection is used to access the functions;
934 the environment pointer provides context and is the first
935 parameter of each function call; for example:
936 <example>
937 jvmtiEnv *jvmti;
938 ...
939 jvmtiError err = (*jvmti)->GetLoadedClasses(jvmti, &class_count, &classes);
940 </example>
941 <p/>
942 When used from the C++ language:
943 functions are accessed as member functions of <code>jvmtiEnv</code>;
944 the environment pointer is not passed to the function call; for example:
945 <example>
946 jvmtiEnv *jvmti;
947 ...
948 jvmtiError err = jvmti->GetLoadedClasses(&class_count, &classes);
949 </example>
950 Unless otherwise stated, all examples and declarations in this
951 specification use the C language.
952 <p/>
953 A <jvmti/> environment can be obtained through the JNI Invocation API
954 <code>GetEnv</code> function:
955 <example>
956 jvmtiEnv *jvmti;
957 ...
958 (*jvm)->GetEnv(jvm, &jvmti, JVMTI_VERSION_1_0);
959 </example>
960 Each call to <code>GetEnv</code>
961 creates a new <jvmti/> connection and thus
962 a new <jvmti/> environment.
963 The <code>version</code> argument of <code>GetEnv</code> must be
964 a <jvmti/> version.
965 The returned environment may have a different version than the
966 requested version but the returned environment must be compatible.
967 <code>GetEnv</code> will return <code>JNI_EVERSION</code> if a
968 compatible version is not available, if <jvmti/> is not supported or
969 <jvmti/> is not supported in the current VM configuration.
970 Other interfaces may be added for creating <jvmti/> environments
971 in specific contexts.
972 Each environment has its own state (for example,
973 <functionlink id="SetEventNotificationMode">desired events</functionlink>,
974 <functionlink id="SetEventCallbacks">event handling functions</functionlink>, and
975 <functionlink id="AddCapabilities">capabilities</functionlink>).
976 An environment is released with
977 <functionlink id="DisposeEnvironment"></functionlink>.
978 Thus, unlike JNI which has one environment per thread, <jvmti/> environments work
979 across threads and are created dynamically.
980 </intro>
981
982 <intro id="functionReturn" label="Function Return Values">
983 <jvmti/> functions always return an
984 <internallink id="ErrorSection">error code</internallink> via the
985 <datalink id="jvmtiError"/> function return value.
986 Some functions can return additional
987 values through pointers provided by the calling function.
988 In some cases, <jvmti/> functions allocate memory that your program must
989 explicitly deallocate. This is indicated in the individual <jvmti/>
990 function descriptions. Empty lists, arrays, sequences, etc are
991 returned as <code>NULL</code>.
992 <p/>
993 In the event that the <jvmti/> function encounters
994 an error (any return value other than <code>JVMTI_ERROR_NONE</code>) the values
995 of memory referenced by argument pointers is undefined, but no memory
996 will have been allocated and no global references will have been allocated.
997 If the error occurs because of invalid input, no action will have occurred.
998 </intro>
999
1000 <intro id="refs" label="Managing JNI Object References">
1001 <jvmti/> functions identify objects with JNI references
1002 (<datalink id="jobject"/> and <datalink id="jclass"/>)
1003 and their derivatives
1004 (<datalink id="jthread"/> and <datalink id="jthreadGroup"/>).
1005 References passed to
1006 <jvmti/> functions can be either global or local, but they must be
1007 strong references. All references returned by <jvmti/> functions are
1008 local references--these local references are created
1009 during the <jvmti/> call.
1010 Local references are a resource that must be managed (see the
1011 <externallink id="http://docs.oracle.com/javase/7/docs/technotes/guides/jni/spec/functions.html#wp18654">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="http://docs.oracle.com/javase/7/docs/technotes/guides/jni/spec/design.html#wp770"
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 <p/>
1491 Note that most <jvmti/> functions that take a thread
1492 as an argument will accept <code>NULL</code> to mean
1493 the current thread.
1494 </description>
1495 <origin>new</origin>
1496 <capabilities>
1497 </capabilities>
1498 <parameters>
1499 <param id="thread_ptr">
1500 <outptr><jthread/></outptr>
1501 <description>
1502 On return, points to the current thread.
1503 </description>
1504 </param>
1505 </parameters>
1506 <errors>
1507 </errors>
1508 </function>
1509
1510 <function id="GetAllThreads" num="4">
1511 <synopsis>Get All Threads</synopsis>
1512 <description>
1513 Get all live threads.
1514 The threads are Java programming language threads;
1515 that is, threads that are attached to the VM.
1516 A thread is live if <code>java.lang.Thread.isAlive()</code>
1517 would return <code>true</code>, that is, the thread has
1518 been started and has not yet died.
1519 The universe of threads is determined by the context of the <jvmti/>
1520 environment, which typically is all threads attached to the VM.
1521 Note that this includes <jvmti/> agent threads
1522 (see <functionlink id="RunAgentThread"/>).
1523 </description>
1524 <origin>jvmdi</origin>
1525 <capabilities>
1526 </capabilities>
1527 <parameters>
1528 <param id="threads_count_ptr">
1529 <outptr><jint/></outptr>
1530 <description>
1531 On return, points to the number of running threads.
1532 </description>
1533 </param>
1534 <param id="threads_ptr">
1535 <allocbuf outcount="threads_count_ptr"><jthread/></allocbuf>
1536 <description>
1537 On return, points to an array of references, one
1538 for each running thread.
1539 </description>
1540 </param>
1541 </parameters>
1542 <errors>
1543 </errors>
1544 </function>
1545
1546 <function id="SuspendThread" num="5">
1547 <synopsis>Suspend Thread</synopsis>
1548 <description>
1549 Suspend the specified thread. If the calling thread is specified,
1550 this function will not return until some other thread calls
1551 <functionlink id="ResumeThread"></functionlink>.
1552 If the thread is currently suspended, this function
1553 does nothing and returns an error.
1554 </description>
1555 <origin>jvmdi</origin>
1556 <capabilities>
1557 <required id="can_suspend"></required>
1558 </capabilities>
1559 <parameters>
1560 <param id="thread">
1561 <jthread null="current"/>
1562 <description>
1563 The thread to suspend.
1564 </description>
1565 </param>
1566 </parameters>
1567 <errors>
1568 <error id="JVMTI_ERROR_THREAD_SUSPENDED">
1569 Thread already suspended.
1570 </error>
1571 </errors>
1572 </function>
1573
1574 <elide>
1575 <function id="SuspendAllThreads" num="101">
1576 <synopsis>Suspend All Threads</synopsis>
1577 <description>
1578 <issue>
1579 There has been no explicit call for this function, and it will
1580 thus be removed if there is no interest.
1581 </issue>
1582 Suspend all live threads except:
1583 <ul>
1584 <li>already suspended threads</li>
1585 <li>those listed in <paramlink id="except_list"></paramlink></li>
1586 <li>certain system (non application) threads, as determined
1587 by the VM implementation</li>
1588 </ul>
1589 The threads are Java programming language threads;
1590 native threads which are not attached to the VM are not
1591 Java programming language threads.
1592 A thread is live if <code>java.lang.Thread.isAlive()</code>
1593 would return <code>true</code>, that is, the thread has
1594 been started and has not yet died.
1595 The universe of threads is determined
1596 by the context of the <jvmti/>
1597 environment, which, typically, is all threads attached to the VM,
1598 except critical VM internal threads and <jvmti/> agent threads
1599 (see <functionlink id="RunAgentThread"/>).
1600 <p/>
1601 If the calling thread is specified,
1602 all other threads are suspended first then the caller thread is suspended -
1603 this function will not return until some other thread calls
1604 <functionlink id="ResumeThread"></functionlink>.
1605 <p/>
1606 The list of actually
1607 suspended threads is returned in
1608 <paramlink id="suspended_list_ptr"></paramlink>.
1609 Suspension is as defined in <functionlink id="SuspendThread"></functionlink>.
1610 <functionlink id="ResumeThreadList"></functionlink>
1611 can be used to resume the suspended threads.
1612 </description>
1613 <origin>new</origin>
1614 <capabilities>
1615 <required id="can_suspend"></required>
1616 </capabilities>
1617 <parameters>
1618 <param id="except_count">
1619 <jint min="0"/>
1620 <description>
1621 The number of threads in the list of threads not to be suspended.
1622 </description>
1623 </param>
1624 <param id="except_list">
1625 <inbuf incount="except_count">
1626 <jthread/>
1627 <nullok>not an error if <code>except_count == 0</code></nullok>
1628 </inbuf>
1629 <description>
1630 The list of threads not to be suspended.
1631 </description>
1632 </param>
1633 <param id="suspended_count_ptr">
1634 <outptr><jint/></outptr>
1635 <description>
1636 On return, points to the number of threads suspended by this call.
1637 </description>
1638 </param>
1639 <param id="suspended_list_ptr">
1640 <allocbuf outcount="suspended_count_ptr"><jthread/></allocbuf>
1641 <description>
1642 On return, points to an array of references, one
1643 for each thread suspended.
1644 </description>
1645 </param>
1646 </parameters>
1647 <errors>
1648 <error id="JVMTI_ERROR_INVALID_THREAD">
1649 A thread in <paramlink id="except_list"></paramlink> was invalid.
1650 </error>
1651 <error id="JVMTI_ERROR_NULL_POINTER">
1652 Both <paramlink id="except_list"></paramlink> was <code>NULL</code>
1653 and <paramlink id="except_count"></paramlink> was non-zero.
1654 </error>
1655 </errors>
1656 </function>
1657 </elide>
1658
1659 <function id="SuspendThreadList" num="92">
1660 <synopsis>Suspend Thread List</synopsis>
1661 <description>
1662 Suspend the <paramlink id="request_count"></paramlink>
1663 threads specified in the
1664 <paramlink id="request_list"></paramlink> array.
1665 Threads may be resumed with
1666 <functionlink id="ResumeThreadList"></functionlink> or
1667 <functionlink id="ResumeThread"></functionlink>.
1668 If the calling thread is specified in the
1669 <paramlink id="request_list"></paramlink> array, this function will
1670 not return until some other thread resumes it.
1671 Errors encountered in the suspension of a thread
1672 are returned in the <paramlink id="results"></paramlink>
1673 array, <b>not</b> in the return value of this function.
1674 Threads that are currently suspended do not change state.
1675 </description>
1676 <origin>jvmdi</origin>
1677 <capabilities>
1678 <required id="can_suspend"></required>
1679 </capabilities>
1680 <parameters>
1681 <param id="request_count">
1682 <jint min="0"/>
1683 <description>
1684 The number of threads to suspend.
1685 </description>
1686 </param>
1687 <param id="request_list">
1688 <inbuf incount="request_count"><jthread/></inbuf>
1689 <description>
1690 The list of threads to suspend.
1691 </description>
1692 </param>
1693 <param id="results">
1694 <outbuf incount="request_count"><enum>jvmtiError</enum></outbuf>
1695 <description>
1696 An agent supplied array of
1697 <paramlink id="request_count"></paramlink> elements.
1698 On return, filled with the error code for
1699 the suspend of the corresponding thread.
1700 The error code will be
1701 <errorlink id="JVMTI_ERROR_NONE"></errorlink>
1702 if the thread was suspended by this call.
1703 Possible error codes are those specified
1704 for <functionlink id="SuspendThread"></functionlink>.
1705 </description>
1706 </param>
1707 </parameters>
1708 <errors>
1709 </errors>
1710 </function>
1711
1712 <function id="ResumeThread" num="6">
1713 <synopsis>Resume Thread</synopsis>
1714 <description>
1715 Resume a suspended thread.
1716 Any threads currently suspended through
1717 a <jvmti/> suspend function (eg.
1718 <functionlink id="SuspendThread"></functionlink>)
1719 or <code>java.lang.Thread.suspend()</code>
1720 will resume execution;
1721 all other threads are unaffected.
1722 </description>
1723 <origin>jvmdi</origin>
1724 <capabilities>
1725 <required id="can_suspend"></required>
1726 </capabilities>
1727 <parameters>
1728 <param id="thread">
1729 <jthread/>
1730 <description>
1731 The thread to resume.
1732 </description>
1733 </param>
1734 </parameters>
1735 <errors>
1736 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
1737 Thread was not suspended.
1738 </error>
1739 <error id="JVMTI_ERROR_INVALID_TYPESTATE">
1740 The state of the thread has been modified, and is now inconsistent.
1741 </error>
1742 </errors>
1743 </function>
1744
1745 <function id="ResumeThreadList" num="93">
1746 <synopsis>Resume Thread List</synopsis>
1747 <description>
1748 Resume the <paramlink id="request_count"></paramlink>
1749 threads specified in the
1750 <paramlink id="request_list"></paramlink> array.
1751 Any thread suspended through
1752 a <jvmti/> suspend function (eg.
1753 <functionlink id="SuspendThreadList"></functionlink>)
1754 or <code>java.lang.Thread.suspend()</code>
1755 will resume execution.
1756 </description>
1757 <origin>jvmdi</origin>
1758 <capabilities>
1759 <required id="can_suspend"></required>
1760 </capabilities>
1761 <parameters>
1762 <param id="request_count">
1763 <jint min="0"/>
1764 <description>
1765 The number of threads to resume.
1766 </description>
1767 </param>
1768 <param id="request_list">
1769 <inbuf incount="request_count"><jthread/></inbuf>
1770 <description>
1771 The threads to resume.
1772 </description>
1773 </param>
1774 <param id="results">
1775 <outbuf incount="request_count"><enum>jvmtiError</enum></outbuf>
1776 <description>
1777 An agent supplied array of
1778 <paramlink id="request_count"></paramlink> elements.
1779 On return, filled with the error code for
1780 the resume of the corresponding thread.
1781 The error code will be
1782 <errorlink id="JVMTI_ERROR_NONE"></errorlink>
1783 if the thread was suspended by this call.
1784 Possible error codes are those specified
1785 for <functionlink id="ResumeThread"></functionlink>.
1786 </description>
1787 </param>
1788 </parameters>
1789 <errors>
1790 </errors>
1791 </function>
1792
1793 <function id="StopThread" num="7">
1794 <synopsis>Stop Thread</synopsis>
1795 <description>
1796 Send the specified asynchronous exception to the specified thread
1797 (similar to <code>java.lang.Thread.stop</code>).
1798 Normally, this function is used to kill the specified thread with an
1799 instance of the exception <code>ThreadDeath</code>.
1800 </description>
1801 <origin>jvmdi</origin>
1802 <capabilities>
1803 <required id="can_signal_thread"></required>
1804 </capabilities>
1805 <parameters>
1806 <param id="thread">
1807 <jthread/>
1808 <description>
1809 The thread to stop.
1810 </description>
1811 </param>
1812 <param id="exception">
1813 <jobject/>
1814 <description>
1815 The asynchronous exception object.
1816 </description>
1817 </param>
1818 </parameters>
1819 <errors>
1820 </errors>
1821 </function>
1822
1823 <function id="InterruptThread" num="8">
1824 <synopsis>Interrupt Thread</synopsis>
1825 <description>
1826 Interrupt the specified thread
1827 (similar to <code>java.lang.Thread.interrupt</code>).
1828 </description>
1829 <origin>jvmdi</origin>
1830 <capabilities>
1831 <required id="can_signal_thread"></required>
1832 </capabilities>
1833 <parameters>
1834 <param id="thread">
1835 <jthread impl="noconvert"/>
1836 <description>
1837 The thread to interrupt.
1838 </description>
1839 </param>
1840 </parameters>
1841 <errors>
1842 </errors>
1843 </function>
1844
1845 <function id="GetThreadInfo" num="9">
1846 <synopsis>Get Thread Info</synopsis>
1847 <typedef id="jvmtiThreadInfo" label="Thread information structure">
1848 <field id="name">
1849 <allocfieldbuf><char/></allocfieldbuf>
1850 <description>
1851 The thread name, encoded as a
1852 <internallink id="mUTF">modified UTF-8</internallink> string.
1853 </description>
1854 </field>
1855 <field id="priority">
1856 <jint/>
1857 <description>
1858 The thread priority. See the thread priority constants:
1859 <datalink id="jvmtiThreadPriority"></datalink>.
1860 </description>
1861 </field>
1862 <field id="is_daemon">
1863 <jboolean/>
1864 <description>
1865 Is this a daemon thread?
1866 </description>
1867 </field>
1868 <field id="thread_group">
1869 <jthreadGroup/>
1870 <description>
1871 The thread group to which this thread belongs.
1872 <code>NULL</code> if the thread has died.
1873 </description>
1874 </field>
1875 <field id="context_class_loader">
1876 <jobject/>
1877 <description>
1878 The context class loader associated with this thread.
1879 </description>
1880 </field>
1881 </typedef>
1882 <description>
1883 Get thread information. The fields of the <datalink id="jvmtiThreadInfo"/> structure
1884 are filled in with details of the specified thread.
1885 </description>
1886 <origin>jvmdi</origin>
1887 <capabilities>
1888 </capabilities>
1889 <parameters>
1890 <param id="thread">
1891 <jthread null="current" impl="noconvert" started="maybe"/>
1892 <description>
1893 The thread to query.
1894 </description>
1895 </param>
1896 <param id="info_ptr">
1897 <outptr><struct>jvmtiThreadInfo</struct></outptr>
1898 <description>
1899 On return, filled with information describing the specified thread.
1900 </description>
1901 </param>
1902 </parameters>
1903 <errors>
1904 </errors>
1905 </function>
1906
1907 <function id="GetOwnedMonitorInfo" num="10">
1908 <synopsis>Get Owned Monitor Info</synopsis>
1909 <description>
1910 Get information about the monitors owned by the
1911 specified thread.
1912 </description>
1913 <origin>jvmdiClone</origin>
1914 <capabilities>
1915 <required id="can_get_owned_monitor_info"></required>
1916 </capabilities>
1917 <parameters>
1918 <param id="thread">
1919 <jthread null="current"/>
1920 <description>
1921 The thread to query.
1922 </description>
1923 </param>
1924 <param id="owned_monitor_count_ptr">
1925 <outptr><jint/></outptr>
1926 <description>
1927 The number of monitors returned.
1928 </description>
1929 </param>
1930 <param id="owned_monitors_ptr">
1931 <allocbuf outcount="owned_monitor_count_ptr"><jobject/></allocbuf>
1932 <description>
1933 The array of owned monitors.
1934 </description>
1935 </param>
1936 </parameters>
1937 <errors>
1938 </errors>
1939 </function>
1940
1941 <function id="GetOwnedMonitorStackDepthInfo" num="153" since="1.1">
1942 <synopsis>Get Owned Monitor Stack Depth Info</synopsis>
1943 <typedef id="jvmtiMonitorStackDepthInfo"
1944 label="Monitor stack depth information structure">
1945 <field id="monitor">
1946 <jobject/>
1947 <description>
1948 The owned monitor.
1949 </description>
1950 </field>
1951 <field id="stack_depth">
1952 <jint/>
1953 <description>
1954 The stack depth. Corresponds to the stack depth used in the
1955 <internallink id="stack">Stack Frame functions</internallink>.
1956 That is, zero is the current frame, one is the frame which
1957 called the current frame. And it is negative one if the
1958 implementation cannot determine the stack depth (e.g., for
1959 monitors acquired by JNI <code>MonitorEnter</code>).
1960 </description>
1961 </field>
1962 </typedef>
1963 <description>
1964 Get information about the monitors owned by the
1965 specified thread and the depth of the stack frame which locked them.
1966 </description>
1967 <origin>new</origin>
1968 <capabilities>
1969 <required id="can_get_owned_monitor_stack_depth_info"></required>
1970 </capabilities>
1971 <parameters>
1972 <param id="thread">
1973 <jthread null="current"/>
1974 <description>
1975 The thread to query.
1976 </description>
1977 </param>
1978 <param id="monitor_info_count_ptr">
1979 <outptr><jint/></outptr>
1980 <description>
1981 The number of monitors returned.
1982 </description>
1983 </param>
1984 <param id="monitor_info_ptr">
1985 <allocbuf outcount="monitor_info_count_ptr">
1986 <struct>jvmtiMonitorStackDepthInfo</struct>
1987 </allocbuf>
1988 <description>
1989 The array of owned monitor depth information.
1990 </description>
1991 </param>
1992 </parameters>
1993 <errors>
1994 </errors>
1995 </function>
1996
1997 <function id="GetCurrentContendedMonitor" num="11">
1998 <synopsis>Get Current Contended Monitor</synopsis>
1999 <description>
2000 Get the object, if any, whose monitor the specified thread is waiting to
2001 enter or waiting to regain through <code>java.lang.Object.wait</code>.
2002 </description>
2003 <origin>jvmdi</origin>
2004 <capabilities>
2005 <required id="can_get_current_contended_monitor"></required>
2006 </capabilities>
2007 <parameters>
2008 <param id="thread">
2009 <jthread null="current"/>
2010 <description>
2011 The thread to query.
2012 </description>
2013 </param>
2014 <param id="monitor_ptr">
2015 <outptr><jobject/></outptr>
2016 <description>
2017 On return, filled with the current contended monitor, or
2018 NULL if there is none.
2019 </description>
2020 </param>
2021 </parameters>
2022 <errors>
2023 </errors>
2024 </function>
2025
2026 <callback id="jvmtiStartFunction">
2027 <void/>
2028 <synopsis>Agent Start Function</synopsis>
2029 <description>
2030 Agent supplied callback function.
2031 This function is the entry point for an agent thread
2032 started with
2033 <functionlink id="RunAgentThread"></functionlink>.
2034 </description>
2035 <parameters>
2036 <param id="jvmti_env">
2037 <outptr>
2038 <struct>jvmtiEnv</struct>
2039 </outptr>
2040 <description>
2041 The <jvmti/> environment.
2042 </description>
2043 </param>
2044 <param id="jni_env">
2045 <outptr>
2046 <struct>JNIEnv</struct>
2047 </outptr>
2048 <description>
2049 The JNI environment.
2050 </description>
2051 </param>
2052 <param id="arg">
2053 <outptr>
2054 <void/>
2055 </outptr>
2056 <description>
2057 The <code>arg</code> parameter passed to
2058 <functionlink id="RunAgentThread"></functionlink>.
2059 </description>
2060 </param>
2061 </parameters>
2062 </callback>
2063
2064 <function id="RunAgentThread" num="12">
2065 <synopsis>Run Agent Thread</synopsis>
2066 <description>
2067 Starts the execution of an agent thread. with the specified native function.
2068 The parameter <paramlink id="arg"></paramlink> is forwarded on to the
2069 <functionlink id="jvmtiStartFunction">start function</functionlink>
2070 (specified with <paramlink id="proc"></paramlink>) as its single argument.
2071 This function allows the creation of agent threads
2072 for handling communication with another process or for handling events
2073 without the need to load a special subclass of <code>java.lang.Thread</code> or
2074 implementer of <code>java.lang.Runnable</code>.
2075 Instead, the created thread can run entirely in native code.
2076 However, the created thread does require a newly created instance
2077 of <code>java.lang.Thread</code> (referenced by the argument <code>thread</code>) to
2078 which it will be associated.
2079 The thread object can be created with JNI calls.
2080 <p/>
2081 The following common thread priorities are provided for your convenience:
2082 <constants id="jvmtiThreadPriority" label="Thread Priority Constants" kind="const">
2083 <constant id="JVMTI_THREAD_MIN_PRIORITY" num="1">
2084 Minimum possible thread priority
2085 </constant>
2086 <constant id="JVMTI_THREAD_NORM_PRIORITY" num="5">
2087 Normal thread priority
2088 </constant>
2089 <constant id="JVMTI_THREAD_MAX_PRIORITY" num="10">
2090 Maximum possible thread priority
2091 </constant>
2092 </constants>
2093 <p/>
2094 The new thread is started as a daemon thread with the specified
2095 <paramlink id="priority"></paramlink>.
2096 If enabled, a <eventlink id="ThreadStart"/> event will be sent.
2097 <p/>
2098 Since the thread has been started, the thread will be live when this function
2099 returns, unless the thread has died immediately.
2100 <p/>
2101 The thread group of the thread is ignored -- specifically, the thread is not
2102 added to the thread group and the thread is not seen on queries of the thread
2103 group at either the Java programming language or <jvmti/> levels.
2104 <p/>
2105 The thread is not visible to Java programming language queries but is
2106 included in <jvmti/> queries (for example,
2107 <functionlink id="GetAllThreads"/> and
2108 <functionlink id="GetAllStackTraces"/>).
2109 <p/>
2110 Upon execution of <code>proc</code>, the new thread will be attached to the
2111 VM--see the JNI documentation on
2112 <externallink id="http://docs.oracle.com/javase/7/docs/technotes/guides/jni/spec/invocation.html#wp1060"
2113 >Attaching to the VM</externallink>.
2114 </description>
2115 <origin>jvmdiClone</origin>
2116 <capabilities>
2117 </capabilities>
2118 <parameters>
2119 <param id="thread">
2120 <jthread impl="noconvert" started="no"/>
2121 <description>
2122 The thread to run.
2123 </description>
2124 </param>
2125 <param id="proc">
2126 <ptrtype>
2127 <struct>jvmtiStartFunction</struct>
2128 </ptrtype>
2129 <description>
2130 The start function.
2131 </description>
2132 </param>
2133 <param id="arg">
2134 <inbuf>
2135 <void/>
2136 <nullok><code>NULL</code> is passed to the start function</nullok>
2137 </inbuf>
2138 <description>
2139 The argument to the start function.
2140 </description>
2141 </param>
2142 <param id="priority">
2143 <jint/>
2144 <description>
2145 The priority of the started thread. Any thread
2146 priority allowed by <code>java.lang.Thread.setPriority</code> can be used including
2147 those in <datalink id="jvmtiThreadPriority"></datalink>.
2148 </description>
2149 </param>
2150 </parameters>
2151 <errors>
2152 <error id="JVMTI_ERROR_INVALID_PRIORITY">
2153 <paramlink id="priority"/> is less than
2154 <datalink id="JVMTI_THREAD_MIN_PRIORITY"/>
2155 or greater than
2156 <datalink id="JVMTI_THREAD_MAX_PRIORITY"/>
2157 </error>
2158 </errors>
2159 </function>
2160
2161 <function id="SetThreadLocalStorage" jkernel="yes" impl="notrace" phase="start" num="103">
2162 <synopsis>Set Thread Local Storage</synopsis>
2163 <description>
2164 The VM stores a pointer value associated with each environment-thread
2165 pair. This pointer value is called <i>thread-local storage</i>.
2166 This value is <code>NULL</code> unless set with this function.
2167 Agents can allocate memory in which they store thread specific
2168 information. By setting thread-local storage it can then be
2169 accessed with
2170 <functionlink id="GetThreadLocalStorage"></functionlink>.
2171 <p/>
2172 This function is called by the agent to set the value of the <jvmti/>
2173 thread-local storage. <jvmti/> supplies to the agent a pointer-size
2174 thread-local storage that can be used to record per-thread
2175 information.
2176 </description>
2177 <origin>jvmpi</origin>
2178 <capabilities>
2179 </capabilities>
2180 <parameters>
2181 <param id="thread">
2182 <jthread null="current"/>
2183 <description>
2184 Store to this thread.
2185 </description>
2186 </param>
2187 <param id="data">
2188 <inbuf>
2189 <void/>
2190 <nullok>value is set to <code>NULL</code></nullok>
2191 </inbuf>
2192 <description>
2193 The value to be entered into the thread-local storage.
2194 </description>
2195 </param>
2196 </parameters>
2197 <errors>
2198 </errors>
2199 </function>
2200
2201 <function id="GetThreadLocalStorage" jkernel="yes" impl="innative notrace" phase="start" num="102">
2202 <synopsis>Get Thread Local Storage</synopsis>
2203 <description>
2204 Called by the agent to get the value of the <jvmti/> thread-local
2205 storage.
2206 </description>
2207 <origin>jvmpi</origin>
2208 <capabilities>
2209 </capabilities>
2210 <parameters>
2211 <param id="thread">
2212 <jthread null="current" impl="noconvert"/>
2213 <description>
2214 Retrieve from this thread.
2215 </description>
2216 </param>
2217 <param id="data_ptr">
2218 <agentbuf><void/></agentbuf>
2219 <description>
2220 Pointer through which the value of the thread local
2221 storage is returned.
2222 If thread-local storage has not been set with
2223 <functionlink id="SetThreadLocalStorage"></functionlink> the returned
2224 pointer is <code>NULL</code>.
2225 </description>
2226 </param>
2227 </parameters>
2228 <errors>
2229 </errors>
2230 </function>
2231
2232 </category>
2233
2234 <category id="thread_groups" label="Thread Group">
2235 <intro>
2236 </intro>
2237
2238 <function id="GetTopThreadGroups" num="13">
2239 <synopsis>Get Top Thread Groups</synopsis>
2240 <description>
2241 Return all top-level (parentless) thread groups in the VM.
2242 </description>
2243 <origin>jvmdi</origin>
2244 <capabilities>
2245 </capabilities>
2246 <parameters>
2247 <param id="group_count_ptr">
2248 <outptr><jint/></outptr>
2249 <description>
2250 On return, points to the number of top-level thread groups.
2251 </description>
2252 </param>
2253 <param id="groups_ptr">
2254 <allocbuf outcount="group_count_ptr"><jthreadGroup/></allocbuf>
2255 <description>
2256 On return, refers to a pointer to the top-level thread group array.
2257 </description>
2258 </param>
2259 </parameters>
2260 <errors>
2261 </errors>
2262 </function>
2263
2264 <function id="GetThreadGroupInfo" num="14">
2265 <synopsis>Get Thread Group Info</synopsis>
2266 <typedef id="jvmtiThreadGroupInfo" label="Thread group information structure">
2267 <field id="parent">
2268 <jthreadGroup/>
2269 <description>
2270 The parent thread group.
2271 </description>
2272 </field>
2273 <field id="name">
2274 <allocfieldbuf><char/></allocfieldbuf>
2275 <description>
2276 The thread group's name, encoded as a
2277 <internallink id="mUTF">modified UTF-8</internallink> string.
2278 </description>
2279 </field>
2280 <field id="max_priority">
2281 <jint/>
2282 <description>
2283 The maximum priority for this thread group.
2284 </description>
2285 </field>
2286 <field id="is_daemon">
2287 <jboolean/>
2288 <description>
2289 Is this a daemon thread group?
2290 </description>
2291 </field>
2292 </typedef>
2293 <description>
2294 Get information about the thread group. The fields of the
2295 <functionlink id="jvmtiThreadGroupInfo"></functionlink> structure
2296 are filled in with details of the specified thread group.
2297 </description>
2298 <origin>jvmdi</origin>
2299 <capabilities>
2300 </capabilities>
2301 <parameters>
2302 <param id="group">
2303 <jthreadGroup/>
2304 <description>
2305 The thread group to query.
2306 </description>
2307 </param>
2308 <param id="info_ptr">
2309 <outptr><struct>jvmtiThreadGroupInfo</struct></outptr>
2310 <description>
2311 On return, filled with information describing the specified
2312 thread group.
2313 </description>
2314 </param>
2315 </parameters>
2316 <errors>
2317 </errors>
2318 </function>
2319
2320 <function id="GetThreadGroupChildren" num="15">
2321 <synopsis>Get Thread Group Children</synopsis>
2322 <description>
2323 Get the live threads and active subgroups in this thread group.
2324 </description>
2325 <origin>jvmdi</origin>
2326 <capabilities>
2327 </capabilities>
2328 <parameters>
2329 <param id="group">
2330 <jthreadGroup/>
2331 <description>
2332 The group to query.
2333 </description>
2334 </param>
2335 <param id="thread_count_ptr">
2336 <outptr><jint/></outptr>
2337 <description>
2338 On return, points to the number of live threads in this thread group.
2339 </description>
2340 </param>
2341 <param id="threads_ptr">
2342 <allocbuf outcount="thread_count_ptr"><jthread/></allocbuf>
2343 <description>
2344 On return, points to an array of the live threads in this thread group.
2345 </description>
2346 </param>
2347 <param id="group_count_ptr">
2348 <outptr><jint/></outptr>
2349 <description>
2350 On return, points to the number of active child thread groups
2351 </description>
2352 </param>
2353 <param id="groups_ptr">
2354 <allocbuf outcount="group_count_ptr"><jthreadGroup/></allocbuf>
2355 <description>
2356 On return, points to an array of the active child thread groups.
2357 </description>
2358 </param>
2359 </parameters>
2360 <errors>
2361 </errors>
2362 </function>
2363 </category>
2364
2365 <category id="stack" label="Stack Frame">
2366 <intro>
2367 These functions provide information about the stack of a thread.
2368 Stack frames are referenced by depth.
2369 The frame at depth zero is the current frame.
2370 <p/>
2371 Stack frames are as described in
2372 <vmspec chapter="3.6"/>,
2373 That is, they correspond to method
2374 invocations (including native methods) but do not correspond to platform native or
2375 VM internal frames.
2376 <p/>
2377 A <jvmti/> implementation may use method invocations to launch a thread and
2378 the corresponding frames may be included in the stack as presented by these functions --
2379 that is, there may be frames shown
2380 deeper than <code>main()</code> and <code>run()</code>.
2381 However this presentation must be consistent across all <jvmti/> functionality which
2382 uses stack frames or stack depth.
2383 </intro>
2384
2385 <typedef id="jvmtiFrameInfo" label="Stack frame information structure">
2386 <description>
2387 Information about a stack frame is returned in this structure.
2388 </description>
2389 <field id="method">
2390 <jmethodID/>
2391 <description>
2392 The method executing in this frame.
2393 </description>
2394 </field>
2395 <field id="location">
2396 <jlocation/>
2397 <description>
2398 The index of the instruction executing in this frame.
2399 <code>-1</code> if the frame is executing a native method.
2400 </description>
2401 </field>
2402 </typedef>
2403
2404 <typedef id="jvmtiStackInfo" label="Stack information structure">
2405 <description>
2406 Information about a set of stack frames is returned in this structure.
2407 </description>
2408 <field id="thread">
2409 <jthread/>
2410 <description>
2411 On return, the thread traced.
2412 </description>
2413 </field>
2414 <field id="state">
2415 <jint/>
2416 <description>
2417 On return, the thread state. See <functionlink id="GetThreadState"></functionlink>.
2418 </description>
2419 </field>
2420 <field id="frame_buffer">
2421 <outbuf incount="max_frame_count">
2422 <struct>jvmtiFrameInfo</struct>
2423 </outbuf>
2424 <description>
2425 On return, this agent allocated buffer is filled
2426 with stack frame information.
2427 </description>
2428 </field>
2429 <field id="frame_count">
2430 <jint/>
2431 <description>
2432 On return, the number of records filled into
2433 <code>frame_buffer</code>.
2434 This will be
2435 min(<code>max_frame_count</code>, <i>stackDepth</i>).
2436 </description>
2437 </field>
2438 </typedef>
2439
2440 <function id="GetStackTrace" num="104">
2441 <synopsis>Get Stack Trace</synopsis>
2442 <description>
2443 Get information about the stack of a thread.
2444 If <paramlink id="max_frame_count"></paramlink> is less than the depth of the stack,
2445 the <paramlink id="max_frame_count"></paramlink> topmost frames are returned,
2446 otherwise the entire stack is returned.
2447 The topmost frames, those most recently invoked, are at the beginning of the returned buffer.
2448 <p/>
2449 The following example causes up to five of the topmost frames
2450 to be returned and (if there are any frames) the currently
2451 executing method name to be printed.
2452 <example>
2453 jvmtiFrameInfo frames[5];
2454 jint count;
2455 jvmtiError err;
2456
2457 err = (*jvmti)->GetStackTrace(jvmti, aThread, 0, 5,
2458 frames, &count);
2459 if (err == JVMTI_ERROR_NONE && count >= 1) {
2460 char *methodName;
2461 err = (*jvmti)->GetMethodName(jvmti, frames[0].method,
2462 &methodName, NULL, NULL);
2463 if (err == JVMTI_ERROR_NONE) {
2464 printf("Executing method: %s", methodName);
2465 }
2466 }
2467 </example>
2468 <todo>
2469 check example code.
2470 </todo>
2471 <p/>
2472 The <paramlink id="thread"></paramlink> need not be suspended
2473 to call this function.
2474 <p/>
2475 The <functionlink id="GetLineNumberTable"></functionlink>
2476 function can be used to map locations to line numbers. Note that
2477 this mapping can be done lazily.
2478 </description>
2479 <origin>jvmpi</origin>
2480 <capabilities>
2481 </capabilities>
2482 <parameters>
2483 <param id="thread">
2484 <jthread null="current"/>
2485 <description>
2486 Fetch the stack trace of this thread.
2487 </description>
2488 </param>
2489 <param id="start_depth">
2490 <jint/>
2491 <description>
2492 Begin retrieving frames at this depth.
2493 If non-negative, count from the current frame,
2494 the first frame retrieved is at depth <code>start_depth</code>.
2495 For example, if zero, start from the current frame; if one, start from the
2496 caller of the current frame; if two, start from the caller of the
2497 caller of the current frame; and so on.
2498 If negative, count from below the oldest frame,
2499 the first frame retrieved is at depth <i>stackDepth</i><code> + start_depth</code>,
2500 where <i>stackDepth</i> is the count of frames on the stack.
2501 For example, if negative one, only the oldest frame is retrieved;
2502 if negative two, start from the frame called by the oldest frame.
2503 </description>
2504 </param>
2505 <param id="max_frame_count">
2506 <jint min="0"/>
2507 <description>
2508 The maximum number of <datalink id="jvmtiFrameInfo"/> records to retrieve.
2509 </description>
2510 </param>
2511 <param id="frame_buffer">
2512 <outbuf incount="max_frame_count" outcount="count_ptr">
2513 <struct>jvmtiFrameInfo</struct>
2514 </outbuf>
2515 <description>
2516 On return, this agent allocated buffer is filled
2517 with stack frame information.
2518 </description>
2519 </param>
2520 <param id="count_ptr">
2521 <outptr><jint/></outptr>
2522 <description>
2523 On return, points to the number of records filled in.
2524 For non-negative <code>start_depth</code>, this will be
2525 min(<code>max_frame_count</code>, <i>stackDepth</i><code> - start_depth</code>).
2526 For negative <code>start_depth</code>, this will be
2527 min(<code>max_frame_count</code>, <code>-start_depth</code>).
2528 </description>
2529 </param>
2530 </parameters>
2531 <errors>
2532 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
2533 <paramlink id="start_depth"/> is positive and greater than or equal to <i>stackDepth</i>.
2534 Or <paramlink id="start_depth"/> is negative and less than <i>-stackDepth</i>.
2535 </error>
2536 </errors>
2537 </function>
2538
2539
2540 <function id="GetAllStackTraces" num="100">
2541 <synopsis>Get All Stack Traces</synopsis>
2542 <description>
2543 Get information about the stacks of all live threads
2544 (including <internallink id="RunAgentThread">agent threads</internallink>).
2545 If <paramlink id="max_frame_count"/> is less than the depth of a stack,
2546 the <paramlink id="max_frame_count"/> topmost frames are returned for that thread,
2547 otherwise the entire stack is returned.
2548 The topmost frames, those most recently invoked, are at the beginning of the returned buffer.
2549 <p/>
2550 All stacks are collected simultaneously, that is, no changes will occur to the
2551 thread state or stacks between the sampling of one thread and the next.
2552 The threads need not be suspended.
2553
2554 <example>
2555 jvmtiStackInfo *stack_info;
2556 jint thread_count;
2557 int ti;
2558 jvmtiError err;
2559
2560 err = (*jvmti)->GetAllStackTraces(jvmti, MAX_FRAMES, &stack_info, &thread_count);
2561 if (err != JVMTI_ERROR_NONE) {
2562 ...
2563 }
2564 for (ti = 0; ti < thread_count; ++ti) {
2565 jvmtiStackInfo *infop = &stack_info[ti];
2566 jthread thread = infop->thread;
2567 jint state = infop->state;
2568 jvmtiFrameInfo *frames = infop->frame_buffer;
2569 int fi;
2570
2571 myThreadAndStatePrinter(thread, state);
2572 for (fi = 0; fi < infop->frame_count; fi++) {
2573 myFramePrinter(frames[fi].method, frames[fi].location);
2574 }
2575 }
2576 /* this one Deallocate call frees all data allocated by GetAllStackTraces */
2577 err = (*jvmti)->Deallocate(jvmti, stack_info);
2578 </example>
2579 <todo>
2580 check example code.
2581 </todo>
2582
2583 </description>
2584 <origin>new</origin>
2585 <capabilities>
2586 </capabilities>
2587 <parameters>
2588 <param id="max_frame_count">
2589 <jint min="0"/>
2590 <description>
2591 The maximum number of <datalink id="jvmtiFrameInfo"/> records to retrieve per thread.
2592 </description>
2593 </param>
2594 <param id="stack_info_ptr">
2595 <allocbuf>
2596 <struct>jvmtiStackInfo</struct>
2597 </allocbuf>
2598 <description>
2599 On return, this buffer is filled
2600 with stack information for each thread.
2601 The number of <datalink id="jvmtiStackInfo"/> records is determined
2602 by <paramlink id="thread_count_ptr"/>.
2603 <p/>
2604 Note that this buffer is allocated to include the <datalink id="jvmtiFrameInfo"/>
2605 buffers pointed to by <datalink id="jvmtiStackInfo.frame_buffer"/>.
2606 These buffers must not be separately deallocated.
2607 </description>
2608 </param>
2609 <param id="thread_count_ptr">
2610 <outptr><jint/></outptr>
2611 <description>
2612 The number of threads traced.
2613 </description>
2614 </param>
2615 </parameters>
2616 <errors>
2617 </errors>
2618 </function>
2619
2620 <function id="GetThreadListStackTraces" num="101">
2621 <synopsis>Get Thread List Stack Traces</synopsis>
2622 <description>
2623 Get information about the stacks of the supplied threads.
2624 If <paramlink id="max_frame_count"/> is less than the depth of a stack,
2625 the <paramlink id="max_frame_count"/> topmost frames are returned for that thread,
2626 otherwise the entire stack is returned.
2627 The topmost frames, those most recently invoked, are at the beginning of the returned buffer.
2628 <p/>
2629 All stacks are collected simultaneously, that is, no changes will occur to the
2630 thread state or stacks between the sampling one thread and the next.
2631 The threads need not be suspended.
2632 <p/>
2633 If a thread has not yet started or terminates before the stack information is collected,
2634 a zero length stack (<datalink id="jvmtiStackInfo.frame_count"/> will be zero)
2635 will be returned and the thread <datalink id="jvmtiStackInfo.state"/> can be checked.
2636 <p/>
2637 See the example for the similar function
2638 <functionlink id="GetAllStackTraces"/>.
2639 </description>
2640 <origin>new</origin>
2641 <capabilities>
2642 </capabilities>
2643 <parameters>
2644 <param id="thread_count">
2645 <jint min="0"/>
2646 <description>
2647 The number of threads to trace.
2648 </description>
2649 </param>
2650 <param id="thread_list">
2651 <inbuf incount="thread_count"><jthread/></inbuf>
2652 <description>
2653 The list of threads to trace.
2654 </description>
2655 </param>
2656 <param id="max_frame_count">
2657 <jint min="0"/>
2658 <description>
2659 The maximum number of <datalink id="jvmtiFrameInfo"/> records to retrieve per thread.
2660 </description>
2661 </param>
2662 <param id="stack_info_ptr">
2663 <allocbuf outcount="thread_count">
2664 <struct>jvmtiStackInfo</struct>
2665 </allocbuf>
2666 <description>
2667 On return, this buffer is filled
2668 with stack information for each thread.
2669 The number of <datalink id="jvmtiStackInfo"/> records is determined
2670 by <paramlink id="thread_count"/>.
2671 <p/>
2672 Note that this buffer is allocated to include the <datalink id="jvmtiFrameInfo"/>
2673 buffers pointed to by <datalink id="jvmtiStackInfo.frame_buffer"/>.
2674 These buffers must not be separately deallocated.
2675 </description>
2676 </param>
2677 </parameters>
2678 <errors>
2679 <error id="JVMTI_ERROR_INVALID_THREAD">
2680 An element in <paramlink id="thread_list"/> is not a thread object.
2681 </error>
2682 </errors>
2683 </function>
2684
2685 <elide>
2686 <function id="AsyncGetStackTrace" num="1000">
2687 <synopsis>Get Stack Trace--Asynchronous</synopsis>
2688 <description>
2689 Get information about the entire stack of a thread (or a sub-section of it).
2690 This is the asynchronous version of <functionlink id="GetStackTrace"></functionlink>
2691 and is reentrant and safe to call
2692 from asynchronous signal handlers.
2693 The stack trace is returned only for the calling thread.
2694 <p/>
2695 The <functionlink id="GetLineNumberTable"></functionlink>
2696 function can be used to map locations to line numbers. Note that
2697 this mapping can be done lazily.
2698 </description>
2699 <origin>jvmpi</origin>
2700 <capabilities>
2701 <required id="can_get_async_stack_trace"></required>
2702 <capability id="can_show_JVM_spec_async_frames">
2703 If <code>false</code>,
2704 <paramlink id="use_java_stack"></paramlink>
2705 must be <code>false</code>.
2706 </capability>
2707 </capabilities>
2708 <parameters>
2709 <param id="use_java_stack">
2710 <jboolean/>
2711 <description>
2712 Return the stack showing <vmspec/>
2713 model of the stack;
2714 otherwise, show the internal representation of the stack with
2715 inlined and optimized methods missing. If the virtual machine
2716 is using the <i>Java Virtual Machine Specification</i> stack model
2717 internally, this flag is ignored.
2718 </description>
2719 </param>
2720 <param id="max_count">
2721 <jint min="0"/>
2722 <description>
2723 The maximum number of <datalink id="jvmtiFrameInfo"/> records to retrieve.
2724 Retrieve this many unless the stack depth is less than <code>max_count</code>.
2725 </description>
2726 </param>
2727 <param id="frame_buffer">
2728 <outbuf incount="max_count" outcount="count_ptr">
2729 <struct>jvmtiFrameInfo</struct>
2730 <nullok>this information is not returned</nullok>
2731 </outbuf>
2732 <description>
2733 The agent passes in a buffer
2734 large enough to hold <code>max_count</code> records of
2735 <datalink id="jvmtiFrameInfo"></datalink>. This buffer must be
2736 pre-allocated by the agent.
2737 </description>
2738 </param>
2739 <param id="count_ptr">
2740 <outptr><jint/></outptr>
2741 <description>
2742 On return, points to the number of records filled in..
2743 </description>
2744 </param>
2745 </parameters>
2746 <errors>
2747 <error id="JVMTI_ERROR_UNATTACHED_THREAD">
2748 The thread being used to call this function is not attached
2749 to the virtual machine. Calls must be made from attached threads.
2750 </error>
2751 </errors>
2752 </function>
2753 </elide>
2754
2755 <function id="GetFrameCount" num="16">
2756 <synopsis>Get Frame Count</synopsis>
2757 <description>
2758 Get the number of frames currently in the specified thread's call stack.
2759 <p/>
2760 If this function is called for a thread actively executing bytecodes (for example,
2761 not the current thread and not suspended), the information returned is transient.
2762 </description>
2763 <origin>jvmdi</origin>
2764 <capabilities>
2765 </capabilities>
2766 <parameters>
2767 <param id="thread">
2768 <jthread null="current"/>
2769 <description>
2770 The thread to query.
2771 </description>
2772 </param>
2773 <param id="count_ptr">
2774 <outptr><jint/></outptr>
2775 <description>
2776 On return, points to the number of frames in the call stack.
2777 </description>
2778 </param>
2779 </parameters>
2780 <errors>
2781 </errors>
2782 </function>
2783
2784 <function id="PopFrame" num="80">
2785 <synopsis>Pop Frame</synopsis>
2786 <description>
2787 Pop the current frame of <code>thread</code>'s stack.
2788 Popping a frame takes you to the previous frame.
2789 When the thread is resumed, the execution
2790 state of the thread is reset to the state
2791 immediately before the called method was invoked.
2792 That is (using <vmspec/> terminology):
2793 <ul>
2794 <li>the current frame is discarded as the previous frame becomes the current one</li>
2795 <li>the operand stack is restored--the argument values are added back
2796 and if the invoke was not <code>invokestatic</code>,
2797 <code>objectref</code> is added back as well</li>
2798 <li>the Java virtual machine PC is restored to the opcode
2799 of the invoke instruction</li>
2800 </ul>
2801 Note however, that any changes to the arguments, which
2802 occurred in the called method, remain;
2803 when execution continues, the first instruction to
2804 execute will be the invoke.
2805 <p/>
2806 Between calling <code>PopFrame</code> and resuming the
2807 thread the state of the stack is undefined.
2808 To pop frames beyond the first,
2809 these three steps must be repeated:
2810 <ul>
2811 <li>suspend the thread via an event (step, breakpoint, ...)</li>
2812 <li>call <code>PopFrame</code></li>
2813 <li>resume the thread</li>
2814 </ul>
2815 <p/>
2816 A lock acquired by calling the called method
2817 (if it is a <code>synchronized</code> method)
2818 and locks acquired by entering <code>synchronized</code>
2819 blocks within the called method are released.
2820 Note: this does not apply to native locks or
2821 <code>java.util.concurrent.locks</code> locks.
2822 <p/>
2823 Finally blocks are not executed.
2824 <p/>
2825 Changes to global state are not addressed and thus remain changed.
2826 <p/>
2827 The specified thread must be suspended (which implies it cannot be the current thread).
2828 <p/>
2829 Both the called method and calling method must be non-native Java programming
2830 language methods.
2831 <p/>
2832 No <jvmti/> events are generated by this function.
2833 </description>
2834 <origin>jvmdi</origin>
2835 <capabilities>
2836 <required id="can_pop_frame"></required>
2837 </capabilities>
2838 <parameters>
2839 <param id="thread">
2840 <jthread/>
2841 <description>
2842 The thread whose current frame is to be popped.
2843 </description>
2844 </param>
2845 </parameters>
2846 <errors>
2847 <error id="JVMTI_ERROR_OPAQUE_FRAME">
2848 Called or calling method is a native method.
2849 The implementation is unable to pop this frame.
2850 </error>
2851 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
2852 Thread was not suspended.
2853 </error>
2854 <error id="JVMTI_ERROR_NO_MORE_FRAMES">
2855 There are less than two stack frames on the call stack.
2856 </error>
2857 </errors>
2858 </function>
2859
2860 <function id="GetFrameLocation" num="19">
2861 <synopsis>Get Frame Location</synopsis>
2862 <description>
2863 <p/>
2864 For a Java programming language frame, return the location of the instruction
2865 currently executing.
2866 </description>
2867 <origin>jvmdiClone</origin>
2868 <capabilities>
2869 </capabilities>
2870 <parameters>
2871 <param id="thread">
2872 <jthread null="current" frame="frame"/>
2873 <description>
2874 The thread of the frame to query.
2875 </description>
2876 </param>
2877 <param id="depth">
2878 <jframeID thread="thread"/>
2879 <description>
2880 The depth of the frame to query.
2881 </description>
2882 </param>
2883 <param id="method_ptr">
2884 <outptr><jmethodID/></outptr>
2885 <description>
2886 On return, points to the method for the current location.
2887 </description>
2888 </param>
2889 <param id="location_ptr">
2890 <outptr><jlocation/></outptr>
2891 <description>
2892 On return, points to the index of the currently
2893 executing instruction.
2894 Is set to <code>-1</code> if the frame is executing
2895 a native method.
2896 </description>
2897 </param>
2898 </parameters>
2899 <errors>
2900 </errors>
2901 </function>
2902
2903 <function id="NotifyFramePop" num="20">
2904 <synopsis>Notify Frame Pop</synopsis>
2905 <description>
2906 When the frame that is currently at <paramlink id="depth"></paramlink>
2907 is popped from the stack, generate a
2908 <eventlink id="FramePop"></eventlink> event. See the
2909 <eventlink id="FramePop"></eventlink> event for details.
2910 Only frames corresponding to non-native Java programming language
2911 methods can receive notification.
2912 <p/>
2913 The specified thread must either be the current thread
2914 or the thread must be suspended.
2915 </description>
2916 <origin>jvmdi</origin>
2917 <capabilities>
2918 <required id="can_generate_frame_pop_events"></required>
2919 </capabilities>
2920 <parameters>
2921 <param id="thread">
2922 <jthread null="current" frame="depth"/>
2923 <description>
2924 The thread of the frame for which the frame pop event will be generated.
2925 </description>
2926 </param>
2927 <param id="depth">
2928 <jframeID thread="thread"/>
2929 <description>
2930 The depth of the frame for which the frame pop event will be generated.
2931 </description>
2932 </param>
2933 </parameters>
2934 <errors>
2935 <error id="JVMTI_ERROR_OPAQUE_FRAME">
2936 The frame at <code>depth</code> is executing a
2937 native method.
2938 </error>
2939 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
2940 Thread was not suspended and was not the current thread.
2941 </error>
2942 </errors>
2943 </function>
2944
2945 </category>
2946
2947 <category id="ForceEarlyReturn" label="Force Early Return">
2948 <intro>
2949 These functions allow an agent to force a method
2950 to return at any point during its execution.
2951 The method which will return early is referred to as the <i>called method</i>.
2952 The called method is the current method
2953 (as defined by
2954 <vmspec chapter="3.6"/>)
2955 for the specified thread at
2956 the time the function is called.
2957 <p/>
2958 The specified thread must be suspended or must be the current thread.
2959 The return occurs when execution of Java programming
2960 language code is resumed on this thread.
2961 Between calling one of these functions and resumption
2962 of thread execution, the state of the stack is undefined.
2963 <p/>
2964 No further instructions are executed in the called method.
2965 Specifically, finally blocks are not executed.
2966 Note: this can cause inconsistent states in the application.
2967 <p/>
2968 A lock acquired by calling the called method
2969 (if it is a <code>synchronized</code> method)
2970 and locks acquired by entering <code>synchronized</code>
2971 blocks within the called method are released.
2972 Note: this does not apply to native locks or
2973 <code>java.util.concurrent.locks</code> locks.
2974 <p/>
2975 Events, such as <eventlink id="MethodExit"></eventlink>,
2976 are generated as they would be in a normal return.
2977 <p/>
2978 The called method must be a non-native Java programming
2979 language method.
2980 Forcing return on a thread with only one frame on the
2981 stack causes the thread to exit when resumed.
2982 </intro>
2983
2984 <function id="ForceEarlyReturnObject" num="81" since="1.1">
2985 <synopsis>Force Early Return - Object</synopsis>
2986 <description>
2987 This function can be used to return from a method whose
2988 result type is <code>Object</code>
2989 or a subclass of <code>Object</code>.
2990 </description>
2991 <origin>new</origin>
2992 <capabilities>
2993 <required id="can_force_early_return"></required>
2994 </capabilities>
2995 <parameters>
2996 <param id="thread">
2997 <jthread null="current"/>
2998 <description>
2999 The thread whose current frame is to return early.
3000 </description>
3001 </param>
3002 <param id="value">
3003 <jobject/>
3004 <description>
3005 The return value for the called frame.
3006 An object or <code>NULL</code>.
3007 </description>
3008 </param>
3009 </parameters>
3010 <errors>
3011 <error id="JVMTI_ERROR_OPAQUE_FRAME">
3012 Attempted to return early from a frame
3013 corresponding to a native method.
3014 Or the implementation is unable to provide
3015 this functionality on this frame.
3016 </error>
3017 <error id="JVMTI_ERROR_TYPE_MISMATCH">
3018 The result type of the called method is not
3019 <code>Object</code> or a subclass of <code>Object</code>.
3020 </error>
3021 <error id="JVMTI_ERROR_TYPE_MISMATCH">
3022 The supplied <paramlink id="value"/> is not compatible with the
3023 result type of the called method.
3024 </error>
3025 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
3026 Thread was not the current thread and was not suspended.
3027 </error>
3028 <error id="JVMTI_ERROR_NO_MORE_FRAMES">
3029 There are no more frames on the call stack.
3030 </error>
3031 </errors>
3032 </function>
3033
3034 <function id="ForceEarlyReturnInt" num="82" since="1.1">
3035 <synopsis>Force Early Return - Int</synopsis>
3036 <description>
3037 This function can be used to return from a method whose
3038 result type is <code>int</code>, <code>short</code>,
3039 <code>char</code>, <code>byte</code>, or
3040 <code>boolean</code>.
3041 </description>
3042 <origin>new</origin>
3043 <capabilities>
3044 <required id="can_force_early_return"></required>
3045 </capabilities>
3046 <parameters>
3047 <param id="thread">
3048 <jthread null="current"/>
3049 <description>
3050 The thread whose current frame is to return early.
3051 </description>
3052 </param>
3053 <param id="value">
3054 <jint/>
3055 <description>
3056 The return value for the called frame.
3057 </description>
3058 </param>
3059 </parameters>
3060 <errors>
3061 <error id="JVMTI_ERROR_OPAQUE_FRAME">
3062 Attempted to return early from a frame
3063 corresponding to a native method.
3064 Or the implementation is unable to provide
3065 this functionality on this frame.
3066 </error>
3067 <error id="JVMTI_ERROR_TYPE_MISMATCH">
3068 The result type of the called method is not
3069 <code>int</code>, <code>short</code>,
3070 <code>char</code>, <code>byte</code>, or
3071 <code>boolean</code>.
3072 </error>
3073 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
3074 Thread was not the current thread and was not suspended.
3075 </error>
3076 <error id="JVMTI_ERROR_NO_MORE_FRAMES">
3077 There are no frames on the call stack.
3078 </error>
3079 </errors>
3080 </function>
3081
3082 <function id="ForceEarlyReturnLong" num="83" since="1.1">
3083 <synopsis>Force Early Return - Long</synopsis>
3084 <description>
3085 This function can be used to return from a method whose
3086 result type is <code>long</code>.
3087 </description>
3088 <origin>new</origin>
3089 <capabilities>
3090 <required id="can_force_early_return"></required>
3091 </capabilities>
3092 <parameters>
3093 <param id="thread">
3094 <jthread null="current"/>
3095 <description>
3096 The thread whose current frame is to return early.
3097 </description>
3098 </param>
3099 <param id="value">
3100 <jlong/>
3101 <description>
3102 The return value for the called frame.
3103 </description>
3104 </param>
3105 </parameters>
3106 <errors>
3107 <error id="JVMTI_ERROR_OPAQUE_FRAME">
3108 Attempted to return early from a frame
3109 corresponding to a native method.
3110 Or the implementation is unable to provide
3111 this functionality on this frame.
3112 </error>
3113 <error id="JVMTI_ERROR_TYPE_MISMATCH">
3114 The result type of the called method is not <code>long</code>.
3115 </error>
3116 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
3117 Thread was not the current thread and was not suspended.
3118 </error>
3119 <error id="JVMTI_ERROR_NO_MORE_FRAMES">
3120 There are no frames on the call stack.
3121 </error>
3122 </errors>
3123 </function>
3124
3125 <function id="ForceEarlyReturnFloat" num="84" since="1.1">
3126 <synopsis>Force Early Return - Float</synopsis>
3127 <description>
3128 This function can be used to return from a method whose
3129 result type is <code>float</code>.
3130 </description>
3131 <origin>new</origin>
3132 <capabilities>
3133 <required id="can_force_early_return"></required>
3134 </capabilities>
3135 <parameters>
3136 <param id="thread">
3137 <jthread null="current"/>
3138 <description>
3139 The thread whose current frame is to return early.
3140 </description>
3141 </param>
3142 <param id="value">
3143 <jfloat/>
3144 <description>
3145 The return value for the called frame.
3146 </description>
3147 </param>
3148 </parameters>
3149 <errors>
3150 <error id="JVMTI_ERROR_OPAQUE_FRAME">
3151 Attempted to return early from a frame
3152 corresponding to a native method.
3153 Or the implementation is unable to provide
3154 this functionality on this frame.
3155 </error>
3156 <error id="JVMTI_ERROR_TYPE_MISMATCH">
3157 The result type of the called method is not <code>float</code>.
3158 </error>
3159 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
3160 Thread was not the current thread and was not suspended.
3161 </error>
3162 <error id="JVMTI_ERROR_NO_MORE_FRAMES">
3163 There are no frames on the call stack.
3164 </error>
3165 </errors>
3166 </function>
3167
3168 <function id="ForceEarlyReturnDouble" num="85" since="1.1">
3169 <synopsis>Force Early Return - Double</synopsis>
3170 <description>
3171 This function can be used to return from a method whose
3172 result type is <code>double</code>.
3173 </description>
3174 <origin>new</origin>
3175 <capabilities>
3176 <required id="can_force_early_return"></required>
3177 </capabilities>
3178 <parameters>
3179 <param id="thread">
3180 <jthread null="current"/>
3181 <description>
3182 The thread whose current frame is to return early.
3183 </description>
3184 </param>
3185 <param id="value">
3186 <jdouble/>
3187 <description>
3188 The return value for the called frame.
3189 </description>
3190 </param>
3191 </parameters>
3192 <errors>
3193 <error id="JVMTI_ERROR_OPAQUE_FRAME">
3194 Attempted to return early from a frame corresponding to a native method.
3195 Or the implementation is unable to provide this functionality on this frame.
3196 </error>
3197 <error id="JVMTI_ERROR_TYPE_MISMATCH">
3198 The result type of the called method is not <code>double</code>.
3199 </error>
3200 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
3201 Thread was not the current thread and was not suspended.
3202 </error>
3203 <error id="JVMTI_ERROR_NO_MORE_FRAMES">
3204 There are no frames on the call stack.
3205 </error>
3206 </errors>
3207 </function>
3208
3209 <function id="ForceEarlyReturnVoid" num="86" since="1.1">
3210 <synopsis>Force Early Return - Void</synopsis>
3211 <description>
3212 This function can be used to return from a method with no result type.
3213 That is, the called method must be declared <code>void</code>.
3214 </description>
3215 <origin>new</origin>
3216 <capabilities>
3217 <required id="can_force_early_return"></required>
3218 </capabilities>
3219 <parameters>
3220 <param id="thread">
3221 <jthread null="current"/>
3222 <description>
3223 The thread whose current frame is to return early.
3224 </description>
3225 </param>
3226 </parameters>
3227 <errors>
3228 <error id="JVMTI_ERROR_OPAQUE_FRAME">
3229 Attempted to return early from a frame
3230 corresponding to a native method.
3231 Or the implementation is unable to provide
3232 this functionality on this frame.
3233 </error>
3234 <error id="JVMTI_ERROR_TYPE_MISMATCH">
3235 The called method has a result type.
3236 </error>
3237 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
3238 Thread was not the current thread and was not suspended.
3239 </error>
3240 <error id="JVMTI_ERROR_NO_MORE_FRAMES">
3241 There are no frames on the call stack.
3242 </error>
3243 </errors>
3244 </function>
3245
3246 </category>
3247
3248 <category id="Heap" label="Heap">
3249 <intro>
3250 These functions are used to analyze the heap.
3251 Functionality includes the ability to view the objects in the
3252 heap and to tag these objects.
3253 </intro>
3254
3255 <intro id="objectTags" label="Object Tags">
3256 A <i>tag</i> is a value associated with an object.
3257 Tags are explicitly set by the agent using the
3258 <functionlink id="SetTag"></functionlink> function or by
3259 callback functions such as <functionlink id="jvmtiHeapIterationCallback"/>.
3260 <p/>
3261 Tags are local to the environment; that is, the tags of one
3262 environment are not visible in another.
3263 <p/>
3264 Tags are <code>jlong</code> values which can be used
3265 simply to mark an object or to store a pointer to more detailed
3266 information. Objects which have not been tagged have a
3267 tag of zero.
3268 Setting a tag to zero makes the object untagged.
3269 </intro>
3270
3271 <intro id="heapCallbacks" label="Heap Callback Functions">
3272 Heap functions which iterate through the heap and recursively
3273 follow object references use agent supplied callback functions
3274 to deliver the information.
3275 <p/>
3276 These heap callback functions must adhere to the following restrictions --
3277 These callbacks must not use JNI functions.
3278 These callbacks must not use <jvmti/> functions except
3279 <i>callback safe</i> functions which
3280 specifically allow such use (see the raw monitor, memory management,
3281 and environment local storage functions).
3282 <p/>
3283 An implementation may invoke a callback on an internal thread or
3284 the thread which called the iteration function.
3285 Heap callbacks are single threaded -- no more than one callback will
3286 be invoked at a time.
3287 <p/>
3288 The Heap Filter Flags can be used to prevent reporting
3289 based on the tag status of an object or its class.
3290 If no flags are set (the <code>jint</code> is zero), objects
3291 will not be filtered out.
3292
3293 <constants id="jvmtiHeapFilter" label="Heap Filter Flags" kind="bits">
3294 <constant id="JVMTI_HEAP_FILTER_TAGGED" num="0x4">
3295 Filter out tagged objects. Objects which are tagged are not included.
3296 </constant>
3297 <constant id="JVMTI_HEAP_FILTER_UNTAGGED" num="0x8">
3298 Filter out untagged objects. Objects which are not tagged are not included.
3299 </constant>
3300 <constant id="JVMTI_HEAP_FILTER_CLASS_TAGGED" num="0x10">
3301 Filter out objects with tagged classes. Objects whose class is tagged are not included.
3302 </constant>
3303 <constant id="JVMTI_HEAP_FILTER_CLASS_UNTAGGED" num="0x20">
3304 Filter out objects with untagged classes. Objects whose class is not tagged are not included.
3305 </constant>
3306 </constants>
3307
3308 <p/>
3309 The Heap Visit Control Flags are returned by the heap callbacks
3310 and can be used to abort the iteration. For the
3311 <functionlink id="jvmtiHeapReferenceCallback">Heap
3312 Reference Callback</functionlink>, it can also be used
3313 to prune the graph of traversed references
3314 (<code>JVMTI_VISIT_OBJECTS</code> is not set).
3315
3316 <constants id="jvmtiHeapVisitControl"
3317 label="Heap Visit Control Flags"
3318 kind="bits"
3319 since="1.1">
3320 <constant id="JVMTI_VISIT_OBJECTS" num="0x100">
3321 If we are visiting an object and if this callback
3322 was initiated by <functionlink id="FollowReferences"/>,
3323 traverse the references of this object.
3324 Otherwise ignored.
3325 </constant>
3326 <constant id="JVMTI_VISIT_ABORT" num="0x8000">
3327 Abort the iteration. Ignore all other bits.
3328 </constant>
3329 </constants>
3330
3331 <p/>
3332 The Heap Reference Enumeration is provided by the
3333 <functionlink id="jvmtiHeapReferenceCallback">Heap
3334 Reference Callback</functionlink> and
3335 <functionlink id="jvmtiPrimitiveFieldCallback">Primitive Field
3336 Callback</functionlink> to
3337 describe the kind of reference
3338 being reported.
3339
3340 <constants id="jvmtiHeapReferenceKind"
3341 label="Heap Reference Enumeration"
3342 kind="enum"
3343 since="1.1">
3344 <constant id="JVMTI_HEAP_REFERENCE_CLASS" num="1">
3345 Reference from an object to its class.
3346 </constant>
3347 <constant id="JVMTI_HEAP_REFERENCE_FIELD" num="2">
3348 Reference from an object to the value of one of its instance fields.
3349 </constant>
3350 <constant id="JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT" num="3">
3351 Reference from an array to one of its elements.
3352 </constant>
3353 <constant id="JVMTI_HEAP_REFERENCE_CLASS_LOADER" num="4">
3354 Reference from a class to its class loader.
3355 </constant>
3356 <constant id="JVMTI_HEAP_REFERENCE_SIGNERS" num="5">
3357 Reference from a class to its signers array.
3358 </constant>
3359 <constant id="JVMTI_HEAP_REFERENCE_PROTECTION_DOMAIN" num="6">
3360 Reference from a class to its protection domain.
3361 </constant>
3362 <constant id="JVMTI_HEAP_REFERENCE_INTERFACE" num="7">
3363 Reference from a class to one of its interfaces.
3364 Note: interfaces are defined via a constant pool reference,
3365 so the referenced interfaces may also be reported with a
3366 <code>JVMTI_HEAP_REFERENCE_CONSTANT_POOL</code> reference kind.
3367 </constant>
3368 <constant id="JVMTI_HEAP_REFERENCE_STATIC_FIELD" num="8">
3369 Reference from a class to the value of one of its static fields.
3370 </constant>
3371 <constant id="JVMTI_HEAP_REFERENCE_CONSTANT_POOL" num="9">
3372 Reference from a class to a resolved entry in the constant pool.
3373 </constant>
3374 <constant id="JVMTI_HEAP_REFERENCE_SUPERCLASS" num="10">
3375 Reference from a class to its superclass.
3376 A callback is bot sent if the superclass is <code>java.lang.Object</code>.
3377 Note: loaded classes define superclasses via a constant pool
3378 reference, so the referenced superclass may also be reported with
3379 a <code>JVMTI_HEAP_REFERENCE_CONSTANT_POOL</code> reference kind.
3380 </constant>
3381 <constant id="JVMTI_HEAP_REFERENCE_JNI_GLOBAL" num="21">
3382 Heap root reference: JNI global reference.
3383 </constant>
3384 <constant id="JVMTI_HEAP_REFERENCE_SYSTEM_CLASS" num="22">
3385 Heap root reference: System class.
3386 </constant>
3387 <constant id="JVMTI_HEAP_REFERENCE_MONITOR" num="23">
3388 Heap root reference: monitor.
3389 </constant>
3390 <constant id="JVMTI_HEAP_REFERENCE_STACK_LOCAL" num="24">
3391 Heap root reference: local variable on the stack.
3392 </constant>
3393 <constant id="JVMTI_HEAP_REFERENCE_JNI_LOCAL" num="25">
3394 Heap root reference: JNI local reference.
3395 </constant>
3396 <constant id="JVMTI_HEAP_REFERENCE_THREAD" num="26">
3397 Heap root reference: Thread.
3398 </constant>
3399 <constant id="JVMTI_HEAP_REFERENCE_OTHER" num="27">
3400 Heap root reference: other heap root reference.
3401 </constant>
3402 </constants>
3403
3404 <p/>
3405 Definitions for the single character type descriptors of
3406 primitive types.
3407
3408 <constants id="jvmtiPrimitiveType"
3409 label="Primitive Type Enumeration"
3410 kind="enum"
3411 since="1.1">
3412 <constant id="JVMTI_PRIMITIVE_TYPE_BOOLEAN" num="90">
3413 'Z' - Java programming language <code>boolean</code> - JNI <code>jboolean</code>
3414 </constant>
3415 <constant id="JVMTI_PRIMITIVE_TYPE_BYTE" num="66">
3416 'B' - Java programming language <code>byte</code> - JNI <code>jbyte</code>
3417 </constant>
3418 <constant id="JVMTI_PRIMITIVE_TYPE_CHAR" num="67">
3419 'C' - Java programming language <code>char</code> - JNI <code>jchar</code>
3420 </constant>
3421 <constant id="JVMTI_PRIMITIVE_TYPE_SHORT" num="83">
3422 'S' - Java programming language <code>short</code> - JNI <code>jshort</code>
3423 </constant>
3424 <constant id="JVMTI_PRIMITIVE_TYPE_INT" num="73">
3425 'I' - Java programming language <code>int</code> - JNI <code>jint</code>
3426 </constant>
3427 <constant id="JVMTI_PRIMITIVE_TYPE_LONG" num="74">
3428 'J' - Java programming language <code>long</code> - JNI <code>jlong</code>
3429 </constant>
3430 <constant id="JVMTI_PRIMITIVE_TYPE_FLOAT" num="70">
3431 'F' - Java programming language <code>float</code> - JNI <code>jfloat</code>
3432 </constant>
3433 <constant id="JVMTI_PRIMITIVE_TYPE_DOUBLE" num="68">
3434 'D' - Java programming language <code>double</code> - JNI <code>jdouble</code>
3435 </constant>
3436 </constants>
3437 </intro>
3438
3439 <typedef id="jvmtiHeapReferenceInfoField"
3440 label="Reference information structure for Field references"
3441 since="1.1">
3442 <description>
3443 Reference information returned for
3444 <datalink id="JVMTI_HEAP_REFERENCE_FIELD"/> and
3445 <datalink id="JVMTI_HEAP_REFERENCE_STATIC_FIELD"/> references.
3446 </description>
3447 <field id="index">
3448 <jint/>
3449 <description>
3450 For <datalink id="JVMTI_HEAP_REFERENCE_FIELD"/>, the
3451 referrer object is not a class or an inteface.
3452 In this case, <code>index</code> is the index of the field
3453 in the class of the referrer object.
3454 This class is referred to below as <i>C</i>.
3455 <p/>
3456 For <datalink id="JVMTI_HEAP_REFERENCE_STATIC_FIELD"/>,
3457 the referrer object is a class (referred to below as <i>C</i>)
3458 or an interface (referred to below as <i>I</i>).
3459 In this case, <code>index</code> is the index of the field in
3460 that class or interface.
3461 <p/>
3462 If the referrer object is not an interface, then the field
3463 indices are determined as follows:
3464 <ul>
3465 <li>make a list of all the fields in <i>C</i> and its
3466 superclasses, starting with all the fields in
3467 <code>java.lang.Object</code> and ending with all the
3468 fields in <i>C</i>.</li>
3469 <li>Within this list, put
3470 the fields for a given class in the order returned by
3471 <functionlink id="GetClassFields"/>.</li>
3472 <li>Assign the fields in this list indices
3473 <i>n</i>, <i>n</i>+1, ..., in order, where <i>n</i>
3474 is the count of the fields in all the interfaces
3475 implemented by <i>C</i>.
3476 Note that <i>C</i> implements all interfaces
3477 directly implemented by its superclasses; as well
3478 as all superinterfaces of these interfaces.</li>
3479 </ul>
3480 If the referrer object is an interface, then the field
3481 indices are determined as follows:
3482 <ul>
3483 <li>make a list of the fields directly declared in
3484 <i>I</i>.</li>
3485 <li>Within this list, put
3486 the fields in the order returned by
3487 <functionlink id="GetClassFields"/>.</li>
3488 <li>Assign the fields in this list indices
3489 <i>n</i>, <i>n</i>+1, ..., in order, where <i>n</i>
3490 is the count of the fields in all the superinterfaces
3491 of <i>I</i>.</li>
3492 </ul>
3493 All fields are included in this computation, regardless of
3494 field modifier (static, public, private, etc).
3495 <p/>
3496 For example, given the following classes and interfaces:
3497 <example>
3498 interface I0 {
3499 int p = 0;
3500 }
3501
3502 interface I1 extends I0 {
3503 int x = 1;
3504 }
3505
3506 interface I2 extends I0 {
3507 int y = 2;
3508 }
3509
3510 class C1 implements I1 {
3511 public static int a = 3;
3512 private int b = 4;
3513 }
3514
3515 class C2 extends C1 implements I2 {
3516 static int q = 5;
3517 final int r = 6;
3518 }
3519 </example>
3520 Assume that <functionlink id="GetClassFields"/> called on
3521 <code>C1</code> returns the fields of <code>C1</code> in the
3522 order: a, b; and that the fields of <code>C2</code> are
3523 returned in the order: q, r.
3524 An instance of class <code>C1</code> will have the
3525 following field indices:
3526 <dl><dd><table>
3527 <tr>
3528 <td>
3529 a
3530 </td>
3531 <td>
3532 2
3533 </td>
3534 <td align="left">
3535 The count of the fields in the interfaces
3536 implemented by <code>C1</code> is two (<i>n</i>=2):
3537 <code>p</code> of <code>I0</code>
3538 and <code>x</code> of <code>I1</code>.
3539 </td>
3540 </tr>
3541 <tr>
3542 <td>
3543 b
3544 </td>
3545 <td>
3546 3
3547 </td>
3548 <td align="left">
3549 the subsequent index.
3550 </td>
3551 </tr>
3552 </table></dd></dl>
3553 The class <code>C1</code> will have the same field indices.
3554 <p/>
3555 An instance of class <code>C2</code> will have the
3556 following field indices:
3557 <dl><dd><table>
3558 <tr>
3559 <td>
3560 a
3561 </td>
3562 <td>
3563 3
3564 </td>
3565 <td align="left">
3566 The count of the fields in the interfaces
3567 implemented by <code>C2</code> is three (<i>n</i>=3):
3568 <code>p</code> of <code>I0</code>,
3569 <code>x</code> of <code>I1</code> and <code>y</code> of <code>I2</code>
3570 (an interface of <code>C2</code>). Note that the field <code>p</code>
3571 of <code>I0</code> is only included once.
3572 </td>
3573 </tr>
3574 <tr>
3575 <td>
3576 b
3577 </td>
3578 <td>
3579 4
3580 </td>
3581 <td align="left">
3582 the subsequent index to "a".
3583 </td>
3584 </tr>
3585 <tr>
3586 <td>
3587 q
3588 </td>
3589 <td>
3590 5
3591 </td>
3592 <td align="left">
3593 the subsequent index to "b".
3594 </td>
3595 </tr>
3596 <tr>
3597 <td>
3598 r
3599 </td>
3600 <td>
3601 6
3602 </td>
3603 <td align="left">
3604 the subsequent index to "q".
3605 </td>
3606 </tr>
3607 </table></dd></dl>
3608 The class <code>C2</code> will have the same field indices.
3609 Note that a field may have a different index depending on the
3610 object that is viewing it -- for example field "a" above.
3611 Note also: not all field indices may be visible from the
3612 callbacks, but all indices are shown for illustrative purposes.
3613 <p/>
3614 The interface <code>I1</code> will have the
3615 following field indices:
3616 <dl><dd><table>
3617 <tr>
3618 <td>
3619 x
3620 </td>
3621 <td>
3622 1
3623 </td>
3624 <td align="left">
3625 The count of the fields in the superinterfaces
3626 of <code>I1</code> is one (<i>n</i>=1):
3627 <code>p</code> of <code>I0</code>.
3628 </td>
3629 </tr>
3630 </table></dd></dl>
3631 </description>
3632 </field>
3633 </typedef>
3634
3635 <typedef id="jvmtiHeapReferenceInfoArray"
3636 label="Reference information structure for Array references"
3637 since="1.1">
3638 <description>
3639 Reference information returned for
3640 <datalink id="JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT"/> references.
3641 </description>
3642 <field id="index">
3643 <jint/>
3644 <description>
3645 The array index.
3646 </description>
3647 </field>
3648 </typedef>
3649
3650 <typedef id="jvmtiHeapReferenceInfoConstantPool"
3651 label="Reference information structure for Constant Pool references"
3652 since="1.1">
3653 <description>
3654 Reference information returned for
3655 <datalink id="JVMTI_HEAP_REFERENCE_CONSTANT_POOL"/> references.
3656 </description>
3657 <field id="index">
3658 <jint/>
3659 <description>
3660 The index into the constant pool of the class. See the description in
3661 <vmspec chapter="4.4"/>.
3662 </description>
3663 </field>
3664 </typedef>
3665
3666 <typedef id="jvmtiHeapReferenceInfoStackLocal"
3667 label="Reference information structure for Local Variable references"
3668 since="1.1">
3669 <description>
3670 Reference information returned for
3671 <datalink id="JVMTI_HEAP_REFERENCE_STACK_LOCAL"/> references.
3672 </description>
3673 <field id="thread_tag">
3674 <jlong/>
3675 <description>
3676 The tag of the thread corresponding to this stack, zero if not tagged.
3677 </description>
3678 </field>
3679 <field id="thread_id">
3680 <jlong/>
3681 <description>
3682 The unique thread ID of the thread corresponding to this stack.
3683 </description>
3684 </field>
3685 <field id="depth">
3686 <jint/>
3687 <description>
3688 The depth of the frame.
3689 </description>
3690 </field>
3691 <field id="method">
3692 <jmethodID/>
3693 <description>
3694 The method executing in this frame.
3695 </description>
3696 </field>
3697 <field id="location">
3698 <jlocation/>
3699 <description>
3700 The currently executing location in this frame.
3701 </description>
3702 </field>
3703 <field id="slot">
3704 <jint/>
3705 <description>
3706 The slot number of the local variable.
3707 </description>
3708 </field>
3709 </typedef>
3710
3711 <typedef id="jvmtiHeapReferenceInfoJniLocal"
3712 label="Reference information structure for JNI local references"
3713 since="1.1">
3714 <description>
3715 Reference information returned for
3716 <datalink id="JVMTI_HEAP_REFERENCE_JNI_LOCAL"/> references.
3717 </description>
3718 <field id="thread_tag">
3719 <jlong/>
3720 <description>
3721 The tag of the thread corresponding to this stack, zero if not tagged.
3722 </description>
3723 </field>
3724 <field id="thread_id">
3725 <jlong/>
3726 <description>
3727 The unique thread ID of the thread corresponding to this stack.
3728 </description>
3729 </field>
3730 <field id="depth">
3731 <jint/>
3732 <description>
3733 The depth of the frame.
3734 </description>
3735 </field>
3736 <field id="method">
3737 <jmethodID/>
3738 <description>
3739 The method executing in this frame.
3740 </description>
3741 </field>
3742 </typedef>
3743
3744 <typedef id="jvmtiHeapReferenceInfoReserved"
3745 label="Reference information structure for Other references"
3746 since="1.1">
3747 <description>
3748 Reference information returned for other references.
3749 </description>
3750 <field id="reserved1">
3751 <jlong/>
3752 <description>
3753 reserved for future use.
3754 </description>
3755 </field>
3756 <field id="reserved2">
3757 <jlong/>
3758 <description>
3759 reserved for future use.
3760 </description>
3761 </field>
3762 <field id="reserved3">
3763 <jlong/>
3764 <description>
3765 reserved for future use.
3766 </description>
3767 </field>
3768 <field id="reserved4">
3769 <jlong/>
3770 <description>
3771 reserved for future use.
3772 </description>
3773 </field>
3774 <field id="reserved5">
3775 <jlong/>
3776 <description>
3777 reserved for future use.
3778 </description>
3779 </field>
3780 <field id="reserved6">
3781 <jlong/>
3782 <description>
3783 reserved for future use.
3784 </description>
3785 </field>
3786 <field id="reserved7">
3787 <jlong/>
3788 <description>
3789 reserved for future use.
3790 </description>
3791 </field>
3792 <field id="reserved8">
3793 <jlong/>
3794 <description>
3795 reserved for future use.
3796 </description>
3797 </field>
3798 </typedef>
3799
3800 <uniontypedef id="jvmtiHeapReferenceInfo"
3801 label="Reference information structure"
3802 since="1.1">
3803 <description>
3804 The information returned about referrers.
3805 Represented as a union of the various kinds of reference information.
3806 </description>
3807 <field id="field">
3808 <struct>jvmtiHeapReferenceInfoField</struct>
3809 <description>
3810 The referrer information for
3811 <datalink id="JVMTI_HEAP_REFERENCE_FIELD"/>
3812 and <datalink id="JVMTI_HEAP_REFERENCE_STATIC_FIELD"/> references.
3813 </description>
3814 </field>
3815 <field id="array">
3816 <struct>jvmtiHeapReferenceInfoArray</struct>
3817 <description>
3818 The referrer information for
3819 For <datalink id="JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT"/> references.
3820 </description>
3821 </field>
3822 <field id="constant_pool">
3823 <struct>jvmtiHeapReferenceInfoConstantPool</struct>
3824 <description>
3825 The referrer information for
3826 For <datalink id="JVMTI_HEAP_REFERENCE_CONSTANT_POOL"/> references.
3827 </description>
3828 </field>
3829 <field id="stack_local">
3830 <struct>jvmtiHeapReferenceInfoStackLocal</struct>
3831 <description>
3832 The referrer information for
3833 For <datalink id="JVMTI_HEAP_REFERENCE_STACK_LOCAL"/> references.
3834 </description>
3835 </field>
3836 <field id="jni_local">
3837 <struct>jvmtiHeapReferenceInfoJniLocal</struct>
3838 <description>
3839 The referrer information for
3840 For <datalink id="JVMTI_HEAP_REFERENCE_JNI_LOCAL"/> references.
3841 </description>
3842 </field>
3843 <field id="other">
3844 <struct>jvmtiHeapReferenceInfoReserved</struct>
3845 <description>
3846 reserved for future use.
3847 </description>
3848 </field>
3849 </uniontypedef>
3850
3851 <typedef id="jvmtiHeapCallbacks"
3852 label="Heap callback function structure"
3853 since="1.1">
3854 <field id="heap_iteration_callback">
3855 <ptrtype>
3856 <struct>jvmtiHeapIterationCallback</struct>
3857 </ptrtype>
3858 <description>
3859 The callback to be called to describe an
3860 object in the heap. Used by the
3861 <functionlink id="IterateThroughHeap"/> function, ignored by the
3862 <functionlink id="FollowReferences"/> function.
3863 </description>
3864 </field>
3865 <field id="heap_reference_callback">
3866 <ptrtype>
3867 <struct>jvmtiHeapReferenceCallback</struct>
3868 </ptrtype>
3869 <description>
3870 The callback to be called to describe an
3871 object reference. Used by the
3872 <functionlink id="FollowReferences"/> function, ignored by the
3873 <functionlink id="IterateThroughHeap"/> function.
3874 </description>
3875 </field>
3876 <field id="primitive_field_callback">
3877 <ptrtype>
3878 <struct>jvmtiPrimitiveFieldCallback</struct>
3879 </ptrtype>
3880 <description>
3881 The callback to be called to describe a
3882 primitive field.
3883 </description>
3884 </field>
3885 <field id="array_primitive_value_callback">
3886 <ptrtype>
3887 <struct>jvmtiArrayPrimitiveValueCallback</struct>
3888 </ptrtype>
3889 <description>
3890 The callback to be called to describe an
3891 array of primitive values.
3892 </description>
3893 </field>
3894 <field id="string_primitive_value_callback">
3895 <ptrtype>
3896 <struct>jvmtiStringPrimitiveValueCallback</struct>
3897 </ptrtype>
3898 <description>
3899 The callback to be called to describe a String value.
3900 </description>
3901 </field>
3902 <field id="reserved5">
3903 <ptrtype>
3904 <struct>jvmtiReservedCallback</struct>
3905 </ptrtype>
3906 <description>
3907 Reserved for future use..
3908 </description>
3909 </field>
3910 <field id="reserved6">
3911 <ptrtype>
3912 <struct>jvmtiReservedCallback</struct>
3913 </ptrtype>
3914 <description>
3915 Reserved for future use..
3916 </description>
3917 </field>
3918 <field id="reserved7">
3919 <ptrtype>
3920 <struct>jvmtiReservedCallback</struct>
3921 </ptrtype>
3922 <description>
3923 Reserved for future use..
3924 </description>
3925 </field>
3926 <field id="reserved8">
3927 <ptrtype>
3928 <struct>jvmtiReservedCallback</struct>
3929 </ptrtype>
3930 <description>
3931 Reserved for future use..
3932 </description>
3933 </field>
3934 <field id="reserved9">
3935 <ptrtype>
3936 <struct>jvmtiReservedCallback</struct>
3937 </ptrtype>
3938 <description>
3939 Reserved for future use..
3940 </description>
3941 </field>
3942 <field id="reserved10">
3943 <ptrtype>
3944 <struct>jvmtiReservedCallback</struct>
3945 </ptrtype>
3946 <description>
3947 Reserved for future use..
3948 </description>
3949 </field>
3950 <field id="reserved11">
3951 <ptrtype>
3952 <struct>jvmtiReservedCallback</struct>
3953 </ptrtype>
3954 <description>
3955 Reserved for future use..
3956 </description>
3957 </field>
3958 <field id="reserved12">
3959 <ptrtype>
3960 <struct>jvmtiReservedCallback</struct>
3961 </ptrtype>
3962 <description>
3963 Reserved for future use..
3964 </description>
3965 </field>
3966 <field id="reserved13">
3967 <ptrtype>
3968 <struct>jvmtiReservedCallback</struct>
3969 </ptrtype>
3970 <description>
3971 Reserved for future use..
3972 </description>
3973 </field>
3974 <field id="reserved14">
3975 <ptrtype>
3976 <struct>jvmtiReservedCallback</struct>
3977 </ptrtype>
3978 <description>
3979 Reserved for future use..
3980 </description>
3981 </field>
3982 <field id="reserved15">
3983 <ptrtype>
3984 <struct>jvmtiReservedCallback</struct>
3985 </ptrtype>
3986 <description>
3987 Reserved for future use..
3988 </description>
3989 </field>
3990 </typedef>
3991
3992
3993 <intro>
3994 <rationale>
3995 The heap dumping functionality (below) uses a callback
3996 for each object. While it would seem that a buffered approach
3997 would provide better throughput, tests do
3998 not show this to be the case--possibly due to locality of
3999 memory reference or array access overhead.
4000 </rationale>
4001
4002 <issue>
4003 Still under investigation as to if java.lang.ref references
4004 are reported as a different type of reference.
4005 </issue>
4006
4007 <issue>
4008 Should or can an indication of the cost or relative cost of
4009 these operations be included?
4010 </issue>
4011
4012 </intro>
4013
4014 <callback id="jvmtiHeapIterationCallback" since="1.1">
4015 <jint/>
4016 <synopsis>Heap Iteration Callback</synopsis>
4017 <description>
4018 Agent supplied callback function.
4019 Describes (but does not pass in) an object in the heap.
4020 <p/>
4021 This function should return a bit vector of the desired
4022 <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>.
4023 This will determine if the entire iteration should be aborted
4024 (the <code>JVMTI_VISIT_OBJECTS</code> flag is ignored).
4025 <p/>
4026 See the <internallink id="heapCallbacks">heap callback
4027 function restrictions</internallink>.
4028 </description>
4029 <parameters>
4030 <param id="class_tag">
4031 <jlong/>
4032 <description>
4033 The tag of the class of object (zero if the class is not tagged).
4034 If the object represents a runtime class,
4035 the <code>class_tag</code> is the tag
4036 associated with <code>java.lang.Class</code>
4037 (zero if <code>java.lang.Class</code> is not tagged).
4038 </description>
4039 </param>
4040 <param id="size">
4041 <jlong/>
4042 <description>
4043 Size of the object (in bytes). See <functionlink id="GetObjectSize"/>.
4044 </description>
4045 </param>
4046 <param id="tag_ptr">
4047 <outptr><jlong/></outptr>
4048 <description>
4049 The object tag value, or zero if the object is not tagged.
4050 To set the tag value to be associated with the object
4051 the agent sets the <code>jlong</code> pointed to by the parameter.
4052 </description>
4053 </param>
4054 <param id="length">
4055 <jint/>
4056 <description>
4057 If this object is an array, the length of the array. Otherwise negative one (-1).
4058 </description>
4059 </param>
4060 <param id="user_data">
4061 <outptr><void/></outptr>
4062 <description>
4063 The user supplied data that was passed into the iteration function.
4064 </description>
4065 </param>
4066 </parameters>
4067 </callback>
4068
4069 <callback id="jvmtiHeapReferenceCallback" since="1.1">
4070 <jint/>
4071 <synopsis>Heap Reference Callback</synopsis>
4072 <description>
4073 Agent supplied callback function.
4074 Describes a reference from an object or the VM (the referrer) to another object
4075 (the referree) or a heap root to a referree.
4076 <p/>
4077 This function should return a bit vector of the desired
4078 <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>.
4079 This will determine if the objects referenced by the referree
4080 should be visited or if the entire iteration should be aborted.
4081 <p/>
4082 See the <internallink id="heapCallbacks">heap callback
4083 function restrictions</internallink>.
4084 </description>
4085 <parameters>
4086 <param id="reference_kind">
4087 <enum>jvmtiHeapReferenceKind</enum>
4088 <description>
4089 The kind of reference.
4090 </description>
4091 </param>
4092 <param id="reference_info">
4093 <inptr>
4094 <struct>jvmtiHeapReferenceInfo</struct>
4095 </inptr>
4096 <description>
4097 Details about the reference.
4098 Set when the <datalink id="jvmtiHeapReferenceCallback.reference_kind">reference_kind</datalink> is
4099 <datalink id="JVMTI_HEAP_REFERENCE_FIELD"/>,
4100 <datalink id="JVMTI_HEAP_REFERENCE_STATIC_FIELD"/>,
4101 <datalink id="JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT"/>,
4102 <datalink id="JVMTI_HEAP_REFERENCE_CONSTANT_POOL"/>,
4103 <datalink id="JVMTI_HEAP_REFERENCE_STACK_LOCAL"/>,
4104 or <datalink id="JVMTI_HEAP_REFERENCE_JNI_LOCAL"/>.
4105 Otherwise <code>NULL</code>.
4106 </description>
4107 </param>
4108 <param id="class_tag">
4109 <jlong/>
4110 <description>
4111 The tag of the class of referree object (zero if the class is not tagged).
4112 If the referree object represents a runtime class,
4113 the <code>class_tag</code> is the tag
4114 associated with <code>java.lang.Class</code>
4115 (zero if <code>java.lang.Class</code> is not tagged).
4116 </description>
4117 </param>
4118 <param id="referrer_class_tag">
4119 <jlong/>
4120 <description>
4121 The tag of the class of the referrer object (zero if the class is not tagged
4122 or the referree is a heap root). If the referrer object represents a runtime
4123 class, the <code>referrer_class_tag</code> is the tag associated with
4124 the <code>java.lang.Class</code>
4125 (zero if <code>java.lang.Class</code> is not tagged).
4126 </description>
4127 </param>
4128 <param id="size">
4129 <jlong/>
4130 <description>
4131 Size of the referree object (in bytes).
4132 See <functionlink id="GetObjectSize"/>.
4133 </description>
4134 </param>
4135 <param id="tag_ptr">
4136 <outptr><jlong/></outptr>
4137 <description>
4138 Points to the referree object tag value, or zero if the object is not
4139 tagged.
4140 To set the tag value to be associated with the object
4141 the agent sets the <code>jlong</code> pointed to by the parameter.
4142 </description>
4143 </param>
4144 <param id="referrer_tag_ptr">
4145 <outptr><jlong/></outptr>
4146 <description>
4147 Points to the tag of the referrer object, or
4148 points to the zero if the referrer
4149 object is not tagged.
4150 <code>NULL</code> if the referrer in not an object (that is,
4151 this callback is reporting a heap root).
4152 To set the tag value to be associated with the referrer object
4153 the agent sets the <code>jlong</code> pointed to by the parameter.
4154 If this callback is reporting a reference from an object to itself,
4155 <code>referrer_tag_ptr == tag_ptr</code>.
4156 </description>
4157 </param>
4158 <param id="length">
4159 <jint/>
4160 <description>
4161 If this object is an array, the length of the array. Otherwise negative one (-1).
4162 </description>
4163 </param>
4164 <param id="user_data">
4165 <outptr><void/></outptr>
4166 <description>
4167 The user supplied data that was passed into the iteration function.
4168 </description>
4169 </param>
4170 </parameters>
4171 </callback>
4172
4173 <callback id="jvmtiPrimitiveFieldCallback" since="1.1">
4174 <jint/>
4175 <synopsis>Primitive Field Callback</synopsis>
4176 <description>
4177 Agent supplied callback function which
4178 describes a primitive field of an object (<i>the object</i>).
4179 A primitive field is a field whose type is a primitive type.
4180 This callback will describe a static field if the object is a class,
4181 and otherwise will describe an instance field.
4182 <p/>
4183 This function should return a bit vector of the desired
4184 <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>.
4185 This will determine if the entire iteration should be aborted
4186 (the <code>JVMTI_VISIT_OBJECTS</code> flag is ignored).
4187 <p/>
4188 See the <internallink id="heapCallbacks">heap callback
4189 function restrictions</internallink>.
4190 </description>
4191 <parameters>
4192 <param id="kind">
4193 <enum>jvmtiHeapReferenceKind</enum>
4194 <description>
4195 The kind of field -- instance or static (<datalink id="JVMTI_HEAP_REFERENCE_FIELD"/> or
4196 <datalink id="JVMTI_HEAP_REFERENCE_STATIC_FIELD"/>).
4197 </description>
4198 </param>
4199 <param id="info">
4200 <inptr>
4201 <struct>jvmtiHeapReferenceInfo</struct>
4202 </inptr>
4203 <description>
4204 Which field (the field index).
4205 </description>
4206 </param>
4207 <param id="object_class_tag">
4208 <jlong/>
4209 <description>
4210 The tag of the class of the object (zero if the class is not tagged).
4211 If the object represents a runtime class, the
4212 <code>object_class_tag</code> is the tag
4213 associated with <code>java.lang.Class</code>
4214 (zero if <code>java.lang.Class</code> is not tagged).
4215 </description>
4216 </param>
4217 <param id="object_tag_ptr">
4218 <outptr><jlong/></outptr>
4219 <description>
4220 Points to the tag of the object, or zero if the object is not
4221 tagged.
4222 To set the tag value to be associated with the object
4223 the agent sets the <code>jlong</code> pointed to by the parameter.
4224 </description>
4225 </param>
4226 <param id="value">
4227 <jvalue/>
4228 <description>
4229 The value of the field.
4230 </description>
4231 </param>
4232 <param id="value_type">
4233 <enum>jvmtiPrimitiveType</enum>
4234 <description>
4235 The type of the field.
4236 </description>
4237 </param>
4238 <param id="user_data">
4239 <outptr><void/></outptr>
4240 <description>
4241 The user supplied data that was passed into the iteration function.
4242 </description>
4243 </param>
4244 </parameters>
4245 </callback>
4246
4247 <callback id="jvmtiArrayPrimitiveValueCallback" since="1.1">
4248 <jint/>
4249 <synopsis>Array Primitive Value Callback</synopsis>
4250 <description>
4251 Agent supplied callback function.
4252 Describes the values in an array of a primitive type.
4253 <p/>
4254 This function should return a bit vector of the desired
4255 <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>.
4256 This will determine if the entire iteration should be aborted
4257 (the <code>JVMTI_VISIT_OBJECTS</code> flag is ignored).
4258 <p/>
4259 See the <internallink id="heapCallbacks">heap callback
4260 function restrictions</internallink>.
4261 </description>
4262 <parameters>
4263 <param id="class_tag">
4264 <jlong/>
4265 <description>
4266 The tag of the class of the array object (zero if the class is not tagged).
4267 </description>
4268 </param>
4269 <param id="size">
4270 <jlong/>
4271 <description>
4272 Size of the array (in bytes).
4273 See <functionlink id="GetObjectSize"/>.
4274 </description>
4275 </param>
4276 <param id="tag_ptr">
4277 <outptr><jlong/></outptr>
4278 <description>
4279 Points to the tag of the array object, or zero if the object is not
4280 tagged.
4281 To set the tag value to be associated with the object
4282 the agent sets the <code>jlong</code> pointed to by the parameter.
4283 </description>
4284 </param>
4285 <param id="element_count">
4286 <jint/>
4287 <description>
4288 The length of the primitive array.
4289 </description>
4290 </param>
4291 <param id="element_type">
4292 <enum>jvmtiPrimitiveType</enum>
4293 <description>
4294 The type of the elements of the array.
4295 </description>
4296 </param>
4297 <param id="elements">
4298 <vmbuf><void/></vmbuf>
4299 <description>
4300 The elements of the array in a packed array of <code>element_count</code>
4301 items of <code>element_type</code> size each.
4302 </description>
4303 </param>
4304 <param id="user_data">
4305 <outptr><void/></outptr>
4306 <description>
4307 The user supplied data that was passed into the iteration function.
4308 </description>
4309 </param>
4310 </parameters>
4311 </callback>
4312
4313 <callback id="jvmtiStringPrimitiveValueCallback" since="1.1">
4314 <jint/>
4315 <synopsis>String Primitive Value Callback</synopsis>
4316 <description>
4317 Agent supplied callback function.
4318 Describes the value of a java.lang.String.
4319 <p/>
4320 This function should return a bit vector of the desired
4321 <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>.
4322 This will determine if the entire iteration should be aborted
4323 (the <code>JVMTI_VISIT_OBJECTS</code> flag is ignored).
4324 <p/>
4325 See the <internallink id="heapCallbacks">heap callback
4326 function restrictions</internallink>.
4327 </description>
4328 <parameters>
4329 <param id="class_tag">
4330 <jlong/>
4331 <description>
4332 The tag of the class of the String class (zero if the class is not tagged).
4333 <issue>Is this needed?</issue>
4334 </description>
4335 </param>
4336 <param id="size">
4337 <jlong/>
4338 <description>
4339 Size of the string (in bytes).
4340 See <functionlink id="GetObjectSize"/>.
4341 </description>
4342 </param>
4343 <param id="tag_ptr">
4344 <outptr><jlong/></outptr>
4345 <description>
4346 Points to the tag of the String object, or zero if the object is not
4347 tagged.
4348 To set the tag value to be associated with the object
4349 the agent sets the <code>jlong</code> pointed to by the parameter.
4350 </description>
4351 </param>
4352 <param id="value">
4353 <vmbuf><jchar/></vmbuf>
4354 <description>
4355 The value of the String, encoded as a Unicode string.
4356 </description>
4357 </param>
4358 <param id="value_length">
4359 <jint/>
4360 <description>
4361 The length of the string.
4362 The length is equal to the number of 16-bit Unicode
4363 characters in the string.
4364 </description>
4365 </param>
4366 <param id="user_data">
4367 <outptr><void/></outptr>
4368 <description>
4369 The user supplied data that was passed into the iteration function.
4370 </description>
4371 </param>
4372 </parameters>
4373 </callback>
4374
4375
4376 <callback id="jvmtiReservedCallback" since="1.1">
4377 <jint/>
4378 <synopsis>reserved for future use Callback</synopsis>
4379 <description>
4380 Placeholder -- reserved for future use.
4381 </description>
4382 <parameters>
4383 </parameters>
4384 </callback>
4385
4386 <function id="FollowReferences" num="115" since="1.1">
4387 <synopsis>Follow References</synopsis>
4388 <description>
4389 This function initiates a traversal over the objects that are
4390 directly and indirectly reachable from the specified object or,
4391 if <code>initial_object</code> is not specified, all objects
4392 reachable from the heap roots.
4393 The heap root are the set of system classes,
4394 JNI globals, references from thread stacks, and other objects used as roots
4395 for the purposes of garbage collection.
4396 <p/>
4397 This function operates by traversing the reference graph.
4398 Let <i>A</i>, <i>B</i>, ... represent objects.
4399 When a reference from <i>A</i> to <i>B</i> is traversed,
4400 when a reference from a heap root to <i>B</i> is traversed,
4401 or when <i>B</i> is specified as the <paramlink id="initial_object"/>,
4402 then <i>B</i> is said to be <i>visited</i>.
4403 A reference from <i>A</i> to <i>B</i> is not traversed until <i>A</i>
4404 is visited.
4405 References are reported in the same order that the references are traversed.
4406 Object references are reported by invoking the agent supplied
4407 callback function <functionlink id="jvmtiHeapReferenceCallback"/>.
4408 In a reference from <i>A</i> to <i>B</i>, <i>A</i> is known
4409 as the <i>referrer</i> and <i>B</i> as the <i>referree</i>.
4410 The callback is invoked exactly once for each reference from a referrer;
4411 this is true even if there are reference cycles or multiple paths to
4412 the referrer.
4413 There may be more than one reference between a referrer and a referree,
4414 each reference is reported.
4415 These references may be distinguished by examining the
4416 <datalink
4417 id="jvmtiHeapReferenceCallback.reference_kind"><code>reference_kind</code></datalink>
4418 and
4419 <datalink
4420 id="jvmtiHeapReferenceCallback.reference_info"><code>reference_info</code></datalink>
4421 parameters of the <functionlink id="jvmtiHeapReferenceCallback"/> callback.
4422 <p/>
4423 This function reports a Java programming language view of object references,
4424 not a virtual machine implementation view. The following object references
4425 are reported when they are non-null:
4426 <ul>
4427 <li>Instance objects report references to each non-primitive instance fields
4428 (including inherited fields).</li>
4429 <li>Instance objects report a reference to the object type (class).</li>
4430 <li>Classes report a reference to the superclass and directly
4431 implemented/extended interfaces.</li>
4432 <li>Classes report a reference to the class loader, protection domain,
4433 signers, and resolved entries in the constant pool.</li>
4434 <li>Classes report a reference to each directly declared non-primitive
4435 static field.</li>
4436 <li>Arrays report a reference to the array type (class) and each
4437 array element.</li>
4438 <li>Primitive arrays report a reference to the array type.</li>
4439 </ul>
4440 <p/>
4441 This function can also be used to examine primitive (non-object) values.
4442 The primitive value of an array or String
4443 is reported after the object has been visited;
4444 it is reported by invoking the agent supplied callback function
4445 <functionlink id="jvmtiArrayPrimitiveValueCallback"/> or
4446 <functionlink id="jvmtiStringPrimitiveValueCallback"/>.
4447 A primitive field
4448 is reported after the object with that field is visited;
4449 it is reported by invoking the agent supplied callback function
4450 <functionlink id="jvmtiPrimitiveFieldCallback"/>.
4451 <p/>
4452 Whether a callback is provided or is <code>NULL</code> only determines
4453 whether the callback will be invoked, it does not influence
4454 which objects are visited nor does it influence whether other callbacks
4455 will be invoked.
4456 However, the
4457 <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>
4458 returned by <functionlink id="jvmtiHeapReferenceCallback"/>
4459 do determine if the objects referenced by the
4460 current object as visited.
4461 The <datalink id="jvmtiHeapFilter">heap filter flags</datalink>
4462 and <paramlink id="klass"/> provided as parameters to this function
4463 do not control which objects are visited but they do control which
4464 objects and primitive values are reported by the callbacks.
4465 For example, if the only callback that was set is
4466 <fieldlink id="array_primitive_value_callback" struct="jvmtiHeapCallbacks"/> and <code>klass</code>
4467 is set to the array of bytes class, then only arrays of byte will be
4468 reported.
4469 The table below summarizes this:
4470 <p/>
4471 <table>
4472 <tr>
4473 <th/>
4474 <th>
4475 Controls objects visited
4476 </th>
4477 <th>
4478 Controls objects reported
4479 </th>
4480 <th>
4481 Controls primitives reported
4482 </th>
4483 </tr>
4484 <tr>
4485 <th align="left">
4486 the
4487 <datalink id="jvmtiHeapVisitControl">Heap Visit Control Flags</datalink>
4488 returned by <functionlink id="jvmtiHeapReferenceCallback"/>
4489 </th>
4490 <td>
4491 <b>Yes</b>
4492 </td>
4493 <td>
4494 <b>Yes</b>, since visits are controlled
4495 </td>
4496 <td>
4497 <b>Yes</b>, since visits are controlled
4498 </td>
4499 </tr>
4500 <tr>
4501 <th align="left">
4502 <fieldlink id="array_primitive_value_callback" struct="jvmtiHeapCallbacks"/>
4503 in <paramlink id="callbacks"/> set
4504 </th>
4505 <td>
4506 No
4507 </td>
4508 <td>
4509 <b>Yes</b>
4510 </td>
4511 <td>
4512 No
4513 </td>
4514 </tr>
4515 <tr>
4516 <th align="left">
4517 <paramlink id="heap_filter"/>
4518 </th>
4519 <td>
4520 No
4521 </td>
4522 <td>
4523 <b>Yes</b>
4524 </td>
4525 <td>
4526 <b>Yes</b>
4527 </td>
4528 </tr>
4529 <tr>
4530 <th align="left">
4531 <paramlink id="klass"/>
4532 </th>
4533 <td>
4534 No
4535 </td>
4536 <td>
4537 <b>Yes</b>
4538 </td>
4539 <td>
4540 <b>Yes</b>
4541 </td>
4542 </tr>
4543 </table>
4544 <p/>
4545 During the execution of this function the state of the heap
4546 does not change: no objects are allocated, no objects are
4547 garbage collected, and the state of objects (including
4548 held values) does not change.
4549 As a result, threads executing Java
4550 programming language code, threads attempting to resume the
4551 execution of Java programming language code, and threads
4552 attempting to execute JNI functions are typically stalled.
4553 </description>
4554 <origin>new</origin>
4555 <capabilities>
4556 <required id="can_tag_objects"></required>
4557 </capabilities>
4558 <parameters>
4559 <param id="heap_filter">
4560 <jint/>
4561 <description>
4562 This bit vector of
4563 <datalink id="jvmtiHeapFilter">heap filter flags</datalink>.
4564 restricts the objects for which the callback function is called.
4565 This applies to both the object and primitive callbacks.
4566 </description>
4567 </param>
4568 <param id="klass">
4569 <ptrtype>
4570 <jclass/>
4571 <nullok>callbacks are not limited to instances of a particular
4572 class</nullok>
4573 </ptrtype>
4574 <description>
4575 Callbacks are only reported when the object is an instance of
4576 this class.
4577 Objects which are instances of a subclass of <code>klass</code>
4578 are not reported.
4579 If <code>klass</code> is an interface, no objects are reported.
4580 This applies to both the object and primitive callbacks.
4581 </description>
4582 </param>
4583 <param id="initial_object">
4584 <ptrtype>
4585 <jobject/>
4586 <nullok>references are followed from the heap roots</nullok>
4587 </ptrtype>
4588 <description>
4589 The object to follow
4590 </description>
4591 </param>
4592 <param id="callbacks">
4593 <inptr>
4594 <struct>jvmtiHeapCallbacks</struct>
4595 </inptr>
4596 <description>
4597 Structure defining the set of callback functions.
4598 </description>
4599 </param>
4600 <param id="user_data">
4601 <inbuf>
4602 <void/>
4603 <nullok><code>NULL</code> is passed as the user supplied data</nullok>
4604 </inbuf>
4605 <description>
4606 User supplied data to be passed to the callback.
4607 </description>
4608 </param>
4609 </parameters>
4610 <errors>
4611 <error id="JVMTI_ERROR_INVALID_CLASS">
4612 <paramlink id="klass"/> is not a valid class.
4613 </error>
4614 <error id="JVMTI_ERROR_INVALID_OBJECT">
4615 <paramlink id="initial_object"/> is not a valid object.
4616 </error>
4617 </errors>
4618 </function>
4619
4620
4621 <function id="IterateThroughHeap" num="116" since="1.1">
4622 <synopsis>Iterate Through Heap</synopsis>
4623 <description>
4624 Initiate an iteration over all objects in the heap.
4625 This includes both reachable and
4626 unreachable objects. Objects are visited in no particular order.
4627 <p/>
4628 Heap objects are reported by invoking the agent supplied
4629 callback function <functionlink id="jvmtiHeapIterationCallback"/>.
4630 References between objects are not reported.
4631 If only reachable objects are desired, or if object reference information
4632 is needed, use <functionlink id="FollowReferences"/>.
4633 <p/>
4634 This function can also be used to examine primitive (non-object) values.
4635 The primitive value of an array or String
4636 is reported after the object has been visited;
4637 it is reported by invoking the agent supplied callback function
4638 <functionlink id="jvmtiArrayPrimitiveValueCallback"/> or
4639 <functionlink id="jvmtiStringPrimitiveValueCallback"/>.
4640 A primitive field
4641 is reported after the object with that field is visited;
4642 it is reported by invoking the agent supplied
4643 callback function
4644 <functionlink id="jvmtiPrimitiveFieldCallback"/>.
4645 <p/>
4646 Unless the iteration is aborted by the
4647 <datalink id="jvmtiHeapVisitControl">Heap Visit Control Flags</datalink>
4648 returned by a callback, all objects in the heap are visited.
4649 Whether a callback is provided or is <code>NULL</code> only determines
4650 whether the callback will be invoked, it does not influence
4651 which objects are visited nor does it influence whether other callbacks
4652 will be invoked.
4653 The <datalink id="jvmtiHeapFilter">heap filter flags</datalink>
4654 and <paramlink id="klass"/> provided as parameters to this function
4655 do not control which objects are visited but they do control which
4656 objects and primitive values are reported by the callbacks.
4657 For example, if the only callback that was set is
4658 <fieldlink id="array_primitive_value_callback" struct="jvmtiHeapCallbacks"/> and <code>klass</code>
4659 is set to the array of bytes class, then only arrays of byte will be
4660 reported. The table below summarizes this (contrast this with
4661 <functionlink id="FollowReferences"/>):
4662 <p/>
4663 <table>
4664 <tr>
4665 <th/>
4666 <th>
4667 Controls objects visited
4668 </th>
4669 <th>
4670 Controls objects reported
4671 </th>
4672 <th>
4673 Controls primitives reported
4674 </th>
4675 </tr>
4676 <tr>
4677 <th align="left">
4678 the
4679 <datalink id="jvmtiHeapVisitControl">Heap Visit Control Flags</datalink>
4680 returned by <functionlink id="jvmtiHeapIterationCallback"/>
4681 </th>
4682 <td>
4683 No<br/>(unless they abort the iteration)
4684 </td>
4685 <td>
4686 No<br/>(unless they abort the iteration)
4687 </td>
4688 <td>
4689 No<br/>(unless they abort the iteration)
4690 </td>
4691 </tr>
4692 <tr>
4693 <th align="left">
4694 <fieldlink id="array_primitive_value_callback" struct="jvmtiHeapCallbacks"/>
4695 in <paramlink id="callbacks"/> set
4696 </th>
4697 <td>
4698 No
4699 </td>
4700 <td>
4701 <b>Yes</b>
4702 </td>
4703 <td>
4704 No
4705 </td>
4706 </tr>
4707 <tr>
4708 <th align="left">
4709 <paramlink id="heap_filter"/>
4710 </th>
4711 <td>
4712 No
4713 </td>
4714 <td>
4715 <b>Yes</b>
4716 </td>
4717 <td>
4718 <b>Yes</b>
4719 </td>
4720 </tr>
4721 <tr>
4722 <th align="left">
4723 <paramlink id="klass"/>
4724 </th>
4725 <td>
4726 No
4727 </td>
4728 <td>
4729 <b>Yes</b>
4730 </td>
4731 <td>
4732 <b>Yes</b>
4733 </td>
4734 </tr>
4735 </table>
4736 <p/>
4737 During the execution of this function the state of the heap
4738 does not change: no objects are allocated, no objects are
4739 garbage collected, and the state of objects (including
4740 held values) does not change.
4741 As a result, threads executing Java
4742 programming language code, threads attempting to resume the
4743 execution of Java programming language code, and threads
4744 attempting to execute JNI functions are typically stalled.
4745 </description>
4746 <origin>new</origin>
4747 <capabilities>
4748 <required id="can_tag_objects"></required>
4749 </capabilities>
4750 <parameters>
4751 <param id="heap_filter">
4752 <jint/>
4753 <description>
4754 This bit vector of
4755 <datalink id="jvmtiHeapFilter">heap filter flags</datalink>.
4756 restricts the objects for which the callback function is called.
4757 This applies to both the object and primitive callbacks.
4758 </description>
4759 </param>
4760 <param id="klass">
4761 <ptrtype>
4762 <jclass/>
4763 <nullok>callbacks are not limited to instances of a particular class</nullok>
4764 </ptrtype>
4765 <description>
4766 Callbacks are only reported when the object is an instance of
4767 this class.
4768 Objects which are instances of a subclass of <code>klass</code>
4769 are not reported.
4770 If <code>klass</code> is an interface, no objects are reported.
4771 This applies to both the object and primitive callbacks.
4772 </description>
4773 </param>
4774 <param id="callbacks">
4775 <inptr>
4776 <struct>jvmtiHeapCallbacks</struct>
4777 </inptr>
4778 <description>
4779 Structure defining the set callback functions.
4780 </description>
4781 </param>
4782 <param id="user_data">
4783 <inbuf>
4784 <void/>
4785 <nullok><code>NULL</code> is passed as the user supplied data</nullok>
4786 </inbuf>
4787 <description>
4788 User supplied data to be passed to the callback.
4789 </description>
4790 </param>
4791 </parameters>
4792 <errors>
4793 <error id="JVMTI_ERROR_INVALID_CLASS">
4794 <paramlink id="klass"/> is not a valid class.
4795 </error>
4796 </errors>
4797 </function>
4798
4799 <function id="GetTag" phase="start" num="106">
4800 <synopsis>Get Tag</synopsis>
4801 <description>
4802 Retrieve the tag associated with an object.
4803 The tag is a long value typically used to store a
4804 unique identifier or pointer to object information.
4805 The tag is set with
4806 <functionlink id="SetTag"></functionlink>.
4807 Objects for which no tags have been set return a
4808 tag value of zero.
4809 </description>
4810 <origin>new</origin>
4811 <capabilities>
4812 <required id="can_tag_objects"></required>
4813 </capabilities>
4814 <parameters>
4815 <param id="object">
4816 <jobject/>
4817 <description>
4818 The object whose tag is to be retrieved.
4819 </description>
4820 </param>
4821 <param id="tag_ptr">
4822 <outptr><jlong/></outptr>
4823 <description>
4824 On return, the referenced long is set to the value
4825 of the tag.
4826 </description>
4827 </param>
4828 </parameters>
4829 <errors>
4830 </errors>
4831 </function>
4832
4833 <function id="SetTag" phase="start" num="107">
4834 <synopsis>Set Tag</synopsis>
4835 <description>
4836 Set the tag associated with an object.
4837 The tag is a long value typically used to store a
4838 unique identifier or pointer to object information.
4839 The tag is visible with
4840 <functionlink id="GetTag"></functionlink>.
4841 </description>
4842 <origin>new</origin>
4843 <capabilities>
4844 <required id="can_tag_objects"></required>
4845 </capabilities>
4846 <parameters>
4847 <param id="object">
4848 <jobject/>
4849 <description>
4850 The object whose tag is to be set.
4851 </description>
4852 </param>
4853 <param id="tag">
4854 <jlong/>
4855 <description>
4856 The new value of the tag.
4857 </description>
4858 </param>
4859 </parameters>
4860 <errors>
4861 </errors>
4862 </function>
4863
4864 <function id="GetObjectsWithTags" num="114">
4865 <synopsis>Get Objects With Tags</synopsis>
4866 <description>
4867 Return objects in the heap with the specified tags.
4868 The format is parallel arrays of objects and tags.
4869 </description>
4870 <origin>new</origin>
4871 <capabilities>
4872 <required id="can_tag_objects"></required>
4873 </capabilities>
4874 <parameters>
4875 <param id="tag_count">
4876 <jint min="0"/>
4877 <description>
4878 Number of tags to scan for.
4879 </description>
4880 </param>
4881 <param id="tags">
4882 <inbuf incount="tag_count">
4883 <jlong/>
4884 </inbuf>
4885 <description>
4886 Scan for objects with these tags.
4887 Zero is not permitted in this array.
4888 </description>
4889 </param>
4890 <param id="count_ptr">
4891 <outptr>
4892 <jint/>
4893 </outptr>
4894 <description>
4895 Return the number of objects with any of the tags
4896 in <paramlink id="tags"/>.
4897 </description>
4898 </param>
4899 <param id="object_result_ptr">
4900 <allocbuf outcount="count_ptr">
4901 <jobject/>
4902 <nullok>this information is not returned</nullok>
4903 </allocbuf>
4904 <description>
4905 Returns the array of objects with any of the tags
4906 in <paramlink id="tags"/>.
4907 </description>
4908 </param>
4909 <param id="tag_result_ptr">
4910 <allocbuf outcount="count_ptr">
4911 <jlong/>
4912 <nullok>this information is not returned</nullok>
4913 </allocbuf>
4914 <description>
4915 For each object in <paramlink id="object_result_ptr"/>,
4916 return the tag at the corresponding index.
4917 </description>
4918 </param>
4919 </parameters>
4920 <errors>
4921 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
4922 Zero is present in <paramlink id="tags"></paramlink>.
4923 </error>
4924 </errors>
4925 </function>
4926
4927 <function id="ForceGarbageCollection" num="108">
4928 <synopsis>Force Garbage Collection</synopsis>
4929 <description>
4930 Force the VM to perform a garbage collection.
4931 The garbage collection is as complete as possible.
4932 This function does not cause finalizers to be run.
4933 This function does not return until the garbage collection
4934 is finished.
4935 <p/>
4936 Although garbage collection is as complete
4937 as possible there is no guarantee that all
4938 <eventlink id="ObjectFree"/>
4939 events will have been
4940 sent by the time that this function
4941 returns. In particular, an object may be
4942 prevented from being freed because it
4943 is awaiting finalization.
4944 </description>
4945 <origin>new</origin>
4946 <capabilities>
4947 </capabilities>
4948 <parameters>
4949 </parameters>
4950 <errors>
4951 </errors>
4952 </function>
4953
4954
4955 </category>
4956
4957 <category id="Heap_1_0" label="Heap (1.0)">
4958 <intro>
4959 <b>
4960 These functions and data types were introduced in the original
4961 <jvmti/> version 1.0 and have been superseded by more
4962 </b>
4963 <internallink id="Heap"><b>powerful and flexible versions</b></internallink>
4964 <b>
4965 which:
4966 </b>
4967 <ul>
4968 <li>
4969 <b>
4970 Allow access to primitive values (the value of Strings, arrays,
4971 and primitive fields)
4972 </b>
4973 </li>
4974 <li>
4975 <b>
4976 Allow the tag of the referrer to be set, thus enabling more
4977 efficient localized reference graph building
4978 </b>
4979 </li>
4980 <li>
4981 <b>
4982 Provide more extensive filtering abilities
4983 </b>
4984 </li>
4985 <li>
4986 <b>
4987 Are extensible, allowing their abilities to grow in future versions of <jvmti/>
4988 </b>
4989 </li>
4990 </ul>
4991 <p/>
4992 <b>Please use the </b>
4993 <internallink id="Heap"><b>current Heap functions</b></internallink>.
4994 <p/>
4995 <constants id="jvmtiHeapObjectFilter" label="Heap Object Filter Enumeration" kind="enum">
4996 <constant id="JVMTI_HEAP_OBJECT_TAGGED" num="1">
4997 Tagged objects only.
4998 </constant>
4999 <constant id="JVMTI_HEAP_OBJECT_UNTAGGED" num="2">
5000 Untagged objects only.
5001 </constant>
5002 <constant id="JVMTI_HEAP_OBJECT_EITHER" num="3">
5003 Either tagged or untagged objects.
5004 </constant>
5005 </constants>
5006
5007 <constants id="jvmtiHeapRootKind" label="Heap Root Kind Enumeration" kind="enum">
5008 <constant id="JVMTI_HEAP_ROOT_JNI_GLOBAL" num="1">
5009 JNI global reference.
5010 </constant>
5011 <constant id="JVMTI_HEAP_ROOT_SYSTEM_CLASS" num="2">
5012 System class.
5013 </constant>
5014 <constant id="JVMTI_HEAP_ROOT_MONITOR" num="3">
5015 Monitor.
5016 </constant>
5017 <constant id="JVMTI_HEAP_ROOT_STACK_LOCAL" num="4">
5018 Stack local.
5019 </constant>
5020 <constant id="JVMTI_HEAP_ROOT_JNI_LOCAL" num="5">
5021 JNI local reference.
5022 </constant>
5023 <constant id="JVMTI_HEAP_ROOT_THREAD" num="6">
5024 Thread.
5025 </constant>
5026 <constant id="JVMTI_HEAP_ROOT_OTHER" num="7">
5027 Other.
5028 </constant>
5029 </constants>
5030
5031 <constants id="jvmtiObjectReferenceKind" label="Object Reference Enumeration" kind="enum">
5032 <constant id="JVMTI_REFERENCE_CLASS" num="1">
5033 Reference from an object to its class.
5034 </constant>
5035 <constant id="JVMTI_REFERENCE_FIELD" num="2">
5036 Reference from an object to the value of one of its instance fields.
5037 For references of this kind the <code>referrer_index</code>
5038 parameter to the <internallink id="jvmtiObjectReferenceCallback">
5039 jvmtiObjectReferenceCallback</internallink> is the index of the
5040 the instance field. The index is based on the order of all the
5041 object's fields. This includes all fields of the directly declared
5042 static and instance fields in the class, and includes all fields (both
5043 public and private) fields declared in superclasses and superinterfaces.
5044 The index is thus calculated by summing the index of the field in the directly
5045 declared class (see <functionlink id="GetClassFields"/>), with the total
5046 number of fields (both public and private) declared in all superclasses
5047 and superinterfaces. The index starts at zero.
5048 </constant>
5049 <constant id="JVMTI_REFERENCE_ARRAY_ELEMENT" num="3">
5050 Reference from an array to one of its elements.
5051 For references of this kind the <code>referrer_index</code>
5052 parameter to the <internallink id="jvmtiObjectReferenceCallback">
5053 jvmtiObjectReferenceCallback</internallink> is the array index.
5054 </constant>
5055 <constant id="JVMTI_REFERENCE_CLASS_LOADER" num="4">
5056 Reference from a class to its class loader.
5057 </constant>
5058 <constant id="JVMTI_REFERENCE_SIGNERS" num="5">
5059 Reference from a class to its signers array.
5060 </constant>
5061 <constant id="JVMTI_REFERENCE_PROTECTION_DOMAIN" num="6">
5062 Reference from a class to its protection domain.
5063 </constant>
5064 <constant id="JVMTI_REFERENCE_INTERFACE" num="7">
5065 Reference from a class to one of its interfaces.
5066 </constant>
5067 <constant id="JVMTI_REFERENCE_STATIC_FIELD" num="8">
5068 Reference from a class to the value of one of its static fields.
5069 For references of this kind the <code>referrer_index</code>
5070 parameter to the <internallink id="jvmtiObjectReferenceCallback">
5071 jvmtiObjectReferenceCallback</internallink> is the index of the
5072 the static field. The index is based on the order of all the
5073 object's fields. This includes all fields of the directly declared
5074 static and instance fields in the class, and includes all fields (both
5075 public and private) fields declared in superclasses and superinterfaces.
5076 The index is thus calculated by summing the index of the field in the directly
5077 declared class (see <functionlink id="GetClassFields"/>), with the total
5078 number of fields (both public and private) declared in all superclasses
5079 and superinterfaces. The index starts at zero.
5080 Note: this definition differs from that in the <jvmti/> 1.0 Specification.
5081 <rationale>No known implementations used the 1.0 definition.</rationale>
5082 </constant>
5083 <constant id="JVMTI_REFERENCE_CONSTANT_POOL" num="9">
5084 Reference from a class to a resolved entry in the constant pool.
5085 For references of this kind the <code>referrer_index</code>
5086 parameter to the <internallink id="jvmtiObjectReferenceCallback">
5087 jvmtiObjectReferenceCallback</internallink> is the index into
5088 constant pool table of the class, starting at 1. See
5089 <vmspec chapter="4.4"/>.
5090 </constant>
5091 </constants>
5092
5093 <constants id="jvmtiIterationControl" label="Iteration Control Enumeration" kind="enum">
5094 <constant id="JVMTI_ITERATION_CONTINUE" num="1">
5095 Continue the iteration.
5096 If this is a reference iteration, follow the references of this object.
5097 </constant>
5098 <constant id="JVMTI_ITERATION_IGNORE" num="2">
5099 Continue the iteration.
5100 If this is a reference iteration, ignore the references of this object.
5101 </constant>
5102 <constant id="JVMTI_ITERATION_ABORT" num="0">
5103 Abort the iteration.
5104 </constant>
5105 </constants>
5106 </intro>
5107
5108 <callback id="jvmtiHeapObjectCallback">
5109 <enum>jvmtiIterationControl</enum>
5110 <synopsis>Heap Object Callback</synopsis>
5111 <description>
5112 Agent supplied callback function.
5113 Describes (but does not pass in) an object in the heap.
5114 <p/>
5115 Return value should be <code>JVMTI_ITERATION_CONTINUE</code> to continue iteration,
5116 or <code>JVMTI_ITERATION_ABORT</code> to stop iteration.
5117 <p/>
5118 See the <internallink id="heapCallbacks">heap callback
5119 function restrictions</internallink>.
5120 </description>
5121 <parameters>
5122 <param id="class_tag">
5123 <jlong/>
5124 <description>
5125 The tag of the class of object (zero if the class is not tagged).
5126 If the object represents a runtime class,
5127 the <code>class_tag</code> is the tag
5128 associated with <code>java.lang.Class</code>
5129 (zero if <code>java.lang.Class</code> is not tagged).
5130 </description>
5131 </param>
5132 <param id="size">
5133 <jlong/>
5134 <description>
5135 Size of the object (in bytes). See <functionlink id="GetObjectSize"/>.
5136 </description>
5137 </param>
5138 <param id="tag_ptr">
5139 <outptr><jlong/></outptr>
5140 <description>
5141 The object tag value, or zero if the object is not tagged.
5142 To set the tag value to be associated with the object
5143 the agent sets the <code>jlong</code> pointed to by the parameter.
5144 </description>
5145 </param>
5146 <param id="user_data">
5147 <outptr><void/></outptr>
5148 <description>
5149 The user supplied data that was passed into the iteration function.
5150 </description>
5151 </param>
5152 </parameters>
5153 </callback>
5154
5155 <callback id="jvmtiHeapRootCallback">
5156 <enum>jvmtiIterationControl</enum>
5157 <synopsis>Heap Root Object Callback</synopsis>
5158 <description>
5159 Agent supplied callback function.
5160 Describes (but does not pass in) an object that is a root for the purposes
5161 of garbage collection.
5162 <p/>
5163 Return value should be <code>JVMTI_ITERATION_CONTINUE</code> to continue iteration,
5164 <code>JVMTI_ITERATION_IGNORE</code> to continue iteration without pursuing
5165 references from referree object or <code>JVMTI_ITERATION_ABORT</code> to stop iteration.
5166 <p/>
5167 See the <internallink id="heapCallbacks">heap callback
5168 function restrictions</internallink>.
5169 </description>
5170 <parameters>
5171 <param id="root_kind">
5172 <enum>jvmtiHeapRootKind</enum>
5173 <description>
5174 The kind of heap root.
5175 </description>
5176 </param>
5177 <param id="class_tag">
5178 <jlong/>
5179 <description>
5180 The tag of the class of object (zero if the class is not tagged).
5181 If the object represents a runtime class, the <code>class_tag</code> is the tag
5182 associated with <code>java.lang.Class</code>
5183 (zero if <code>java.lang.Class</code> is not tagged).
5184 </description>
5185 </param>
5186 <param id="size">
5187 <jlong/>
5188 <description>
5189 Size of the object (in bytes). See <functionlink id="GetObjectSize"/>.
5190 </description>
5191 </param>
5192 <param id="tag_ptr">
5193 <outptr><jlong/></outptr>
5194 <description>
5195 The object tag value, or zero if the object is not tagged.
5196 To set the tag value to be associated with the object
5197 the agent sets the <code>jlong</code> pointed to by the parameter.
5198 </description>
5199 </param>
5200 <param id="user_data">
5201 <outptr><void/></outptr>
5202 <description>
5203 The user supplied data that was passed into the iteration function.
5204 </description>
5205 </param>
5206 </parameters>
5207 </callback>
5208
5209 <callback id="jvmtiStackReferenceCallback">
5210 <enum>jvmtiIterationControl</enum>
5211 <synopsis>Stack Reference Object Callback</synopsis>
5212 <description>
5213 Agent supplied callback function.
5214 Describes (but does not pass in) an object on the stack that is a root for
5215 the purposes of garbage collection.
5216 <p/>
5217 Return value should be <code>JVMTI_ITERATION_CONTINUE</code> to continue iteration,
5218 <code>JVMTI_ITERATION_IGNORE</code> to continue iteration without pursuing
5219 references from referree object or <code>JVMTI_ITERATION_ABORT</code> to stop iteration.
5220 <p/>
5221 See the <internallink id="heapCallbacks">heap callback
5222 function restrictions</internallink>.
5223 </description>
5224 <parameters>
5225 <param id="root_kind">
5226 <enum>jvmtiHeapRootKind</enum>
5227 <description>
5228 The kind of root (either <code>JVMTI_HEAP_ROOT_STACK_LOCAL</code> or
5229 <code>JVMTI_HEAP_ROOT_JNI_LOCAL</code>).
5230 </description>
5231 </param>
5232 <param id="class_tag">
5233 <jlong/>
5234 <description>
5235 The tag of the class of object (zero if the class is not tagged).
5236 If the object represents a runtime class, the <code>class_tag</code> is the tag
5237 associated with <code>java.lang.Class</code>
5238 (zero if <code>java.lang.Class</code> is not tagged).
5239 </description>
5240 </param>
5241 <param id="size">
5242 <jlong/>
5243 <description>
5244 Size of the object (in bytes). See <functionlink id="GetObjectSize"/>.
5245 </description>
5246 </param>
5247 <param id="tag_ptr">
5248 <outptr><jlong/></outptr>
5249 <description>
5250 The object tag value, or zero if the object is not tagged.
5251 To set the tag value to be associated with the object
5252 the agent sets the <code>jlong</code> pointed to by the parameter.
5253 </description>
5254 </param>
5255 <param id="thread_tag">
5256 <jlong/>
5257 <description>
5258 The tag of the thread corresponding to this stack, zero if not tagged.
5259 </description>
5260 </param>
5261 <param id="depth">
5262 <jint/>
5263 <description>
5264 The depth of the frame.
5265 </description>
5266 </param>
5267 <param id="method">
5268 <jmethodID/>
5269 <description>
5270 The method executing in this frame.
5271 </description>
5272 </param>
5273 <param id="slot">
5274 <jint/>
5275 <description>
5276 The slot number.
5277 </description>
5278 </param>
5279 <param id="user_data">
5280 <outptr><void/></outptr>
5281 <description>
5282 The user supplied data that was passed into the iteration function.
5283 </description>
5284 </param>
5285 </parameters>
5286 </callback>
5287
5288 <callback id="jvmtiObjectReferenceCallback">
5289 <enum>jvmtiIterationControl</enum>
5290 <synopsis>Object Reference Callback</synopsis>
5291 <description>
5292 Agent supplied callback function.
5293 Describes a reference from an object (the referrer) to another object
5294 (the referree).
5295 <p/>
5296 Return value should be <code>JVMTI_ITERATION_CONTINUE</code> to continue iteration,
5297 <code>JVMTI_ITERATION_IGNORE</code> to continue iteration without pursuing
5298 references from referree object or <code>JVMTI_ITERATION_ABORT</code> to stop iteration.
5299 <p/>
5300 See the <internallink id="heapCallbacks">heap callback
5301 function restrictions</internallink>.
5302 </description>
5303 <parameters>
5304 <param id="reference_kind">
5305 <enum>jvmtiObjectReferenceKind</enum>
5306 <description>
5307 The type of reference.
5308 </description>
5309 </param>
5310 <param id="class_tag">
5311 <jlong/>
5312 <description>
5313 The tag of the class of referree object (zero if the class is not tagged).
5314 If the referree object represents a runtime class,
5315 the <code>class_tag</code> is the tag
5316 associated with <code>java.lang.Class</code>
5317 (zero if <code>java.lang.Class</code> is not tagged).
5318 </description>
5319 </param>
5320 <param id="size">
5321 <jlong/>
5322 <description>
5323 Size of the referree object (in bytes).
5324 See <functionlink id="GetObjectSize"/>.
5325 </description>
5326 </param>
5327 <param id="tag_ptr">
5328 <outptr><jlong/></outptr>
5329 <description>
5330 The referree object tag value, or zero if the object is not
5331 tagged.
5332 To set the tag value to be associated with the object
5333 the agent sets the <code>jlong</code> pointed to by the parameter.
5334 </description>
5335 </param>
5336 <param id="referrer_tag">
5337 <jlong/>
5338 <description>
5339 The tag of the referrer object, or zero if the referrer
5340 object is not tagged.
5341 </description>
5342 </param>
5343 <param id="referrer_index">
5344 <jint/>
5345 <description>
5346 For references of type <code>JVMTI_REFERENCE_FIELD</code> or
5347 <code>JVMTI_REFERENCE_STATIC_FIELD</code> the index
5348 of the field in the referrer object. The index is based on the
5349 order of all the object's fields - see <internallink
5350 id="JVMTI_REFERENCE_FIELD">JVMTI_REFERENCE_FIELD</internallink>
5351 or <internallink
5352 id="JVMTI_REFERENCE_STATIC_FIELD">JVMTI_REFERENCE_STATIC_FIELD
5353 </internallink> for further description.
5354 <p/>
5355 For references of type <code>JVMTI_REFERENCE_ARRAY_ELEMENT</code>
5356 the array index - see <internallink id="JVMTI_REFERENCE_ARRAY_ELEMENT">
5357 JVMTI_REFERENCE_ARRAY_ELEMENT</internallink> for further description.
5358 <p/>
5359 For references of type <code>JVMTI_REFERENCE_CONSTANT_POOL</code>
5360 the index into the constant pool of the class - see
5361 <internallink id="JVMTI_REFERENCE_CONSTANT_POOL">
5362 JVMTI_REFERENCE_CONSTANT_POOL</internallink> for further
5363 description.
5364 <p/>
5365 For references of other kinds the <code>referrer_index</code> is
5366 <code>-1</code>.
5367 </description>
5368 </param>
5369 <param id="user_data">
5370 <outptr><void/></outptr>
5371 <description>
5372 The user supplied data that was passed into the iteration function.
5373 </description>
5374 </param>
5375 </parameters>
5376 </callback>
5377
5378 <function id="IterateOverObjectsReachableFromObject" num="109">
5379 <synopsis>Iterate Over Objects Reachable From Object</synopsis>
5380 <description>
5381 This function iterates over all objects that are directly
5382 and indirectly reachable from the specified object.
5383 For each object <i>A</i> (known
5384 as the referrer) with a reference to object <i>B</i> the specified
5385 callback function is called to describe the object reference.
5386 The callback is called exactly once for each reference from a referrer;
5387 this is true even if there are reference cycles or multiple paths to
5388 the referrer.
5389 There may be more than one reference between a referrer and a referree,
5390 These may be distinguished by the
5391 <datalink id="jvmtiObjectReferenceCallback.reference_kind"></datalink> and
5392 <datalink id="jvmtiObjectReferenceCallback.referrer_index"></datalink>.
5393 The callback for an object will always occur after the callback for
5394 its referrer.
5395 <p/>
5396 See <functionlink id="FollowReferences"/> for the object
5397 references which are reported.
5398 <p/>
5399 During the execution of this function the state of the heap
5400 does not change: no objects are allocated, no objects are
5401 garbage collected, and the state of objects (including
5402 held values) does not change.
5403 As a result, threads executing Java
5404 programming language code, threads attempting to resume the
5405 execution of Java programming language code, and threads
5406 attempting to execute JNI functions are typically stalled.
5407 </description>
5408 <origin>new</origin>
5409 <capabilities>
5410 <required id="can_tag_objects"></required>
5411 </capabilities>
5412 <parameters>
5413 <param id="object">
5414 <jobject/>
5415 <description>
5416 The object
5417 </description>
5418 </param>
5419 <param id="object_reference_callback">
5420 <ptrtype>
5421 <struct>jvmtiObjectReferenceCallback</struct>
5422 </ptrtype>
5423 <description>
5424 The callback to be called to describe each
5425 object reference.
5426 </description>
5427 </param>
5428 <param id="user_data">
5429 <inbuf>
5430 <void/>
5431 <nullok><code>NULL</code> is passed as the user supplied data</nullok>
5432 </inbuf>
5433 <description>
5434 User supplied data to be passed to the callback.
5435 </description>
5436 </param>
5437 </parameters>
5438 <errors>
5439 </errors>
5440 </function>
5441
5442 <function id="IterateOverReachableObjects" num="110">
5443 <synopsis>Iterate Over Reachable Objects</synopsis>
5444 <description>
5445 This function iterates over the root objects and all objects that
5446 are directly and indirectly reachable from the root objects.
5447 The root objects comprise the set of system classes,
5448 JNI globals, references from thread stacks, and other objects used as roots
5449 for the purposes of garbage collection.
5450 <p/>
5451 For each root the <paramlink id="heap_root_callback"></paramlink>
5452 or <paramlink id="stack_ref_callback"></paramlink> callback is called.
5453 An object can be a root object for more than one reason and in that case
5454 the appropriate callback is called for each reason.
5455 <p/>
5456 For each object reference the <paramlink id="object_ref_callback"></paramlink>
5457 callback function is called to describe the object reference.
5458 The callback is called exactly once for each reference from a referrer;
5459 this is true even if there are reference cycles or multiple paths to
5460 the referrer.
5461 There may be more than one reference between a referrer and a referree,
5462 These may be distinguished by the
5463 <datalink id="jvmtiObjectReferenceCallback.reference_kind"></datalink> and
5464 <datalink id="jvmtiObjectReferenceCallback.referrer_index"></datalink>.
5465 The callback for an object will always occur after the callback for
5466 its referrer.
5467 <p/>
5468 See <functionlink id="FollowReferences"/> for the object
5469 references which are reported.
5470 <p/>
5471 Roots are always reported to the profiler before any object references
5472 are reported. In other words, the <paramlink id="object_ref_callback"></paramlink>
5473 callback will not be called until the appropriate callback has been called
5474 for all roots. If the <paramlink id="object_ref_callback"></paramlink> callback is
5475 specified as <code>NULL</code> then this function returns after
5476 reporting the root objects to the profiler.
5477 <p/>
5478 During the execution of this function the state of the heap
5479 does not change: no objects are allocated, no objects are
5480 garbage collected, and the state of objects (including
5481 held values) does not change.
5482 As a result, threads executing Java
5483 programming language code, threads attempting to resume the
5484 execution of Java programming language code, and threads
5485 attempting to execute JNI functions are typically stalled.
5486 </description>
5487 <origin>new</origin>
5488 <capabilities>
5489 <required id="can_tag_objects"></required>
5490 </capabilities>
5491 <parameters>
5492 <param id="heap_root_callback">
5493 <ptrtype>
5494 <struct>jvmtiHeapRootCallback</struct>
5495 <nullok>do not report heap roots</nullok>
5496 </ptrtype>
5497 <description>
5498 The callback function to be called for each heap root of type
5499 <code>JVMTI_HEAP_ROOT_JNI_GLOBAL</code>,
5500 <code>JVMTI_HEAP_ROOT_SYSTEM_CLASS</code>,
5501 <code>JVMTI_HEAP_ROOT_MONITOR</code>,
5502 <code>JVMTI_HEAP_ROOT_THREAD</code>, or
5503 <code>JVMTI_HEAP_ROOT_OTHER</code>.
5504 </description>
5505 </param>
5506 <param id="stack_ref_callback">
5507 <ptrtype>
5508 <struct>jvmtiStackReferenceCallback</struct>
5509 <nullok>do not report stack references</nullok>
5510 </ptrtype>
5511 <description>
5512 The callback function to be called for each heap root of
5513 <code>JVMTI_HEAP_ROOT_STACK_LOCAL</code> or
5514 <code>JVMTI_HEAP_ROOT_JNI_LOCAL</code>.
5515 </description>
5516 </param>
5517 <param id="object_ref_callback">
5518 <ptrtype>
5519 <struct>jvmtiObjectReferenceCallback</struct>
5520 <nullok>do not follow references from the root objects</nullok>
5521 </ptrtype>
5522 <description>
5523 The callback function to be called for each object reference.
5524 </description>
5525 </param>
5526 <param id="user_data">
5527 <inbuf>
5528 <void/>
5529 <nullok><code>NULL</code> is passed as the user supplied data</nullok>
5530 </inbuf>
5531 <description>
5532 User supplied data to be passed to the callback.
5533 </description>
5534 </param>
5535 </parameters>
5536 <errors>
5537 </errors>
5538 </function>
5539
5540 <function id="IterateOverHeap" num="111">
5541 <synopsis>Iterate Over Heap</synopsis>
5542 <description>
5543 Iterate over all objects in the heap. This includes both reachable and
5544 unreachable objects.
5545 <p/>
5546 The <paramlink id="object_filter"></paramlink> parameter indicates the
5547 objects for which the callback function is called. If this parameter
5548 is <code>JVMTI_HEAP_OBJECT_TAGGED</code> then the callback will only be
5549 called for every object that is tagged. If the parameter is
5550 <code>JVMTI_HEAP_OBJECT_UNTAGGED</code> then the callback will only be
5551 for objects that are not tagged. If the parameter
5552 is <code>JVMTI_HEAP_OBJECT_EITHER</code> then the callback will be
5553 called for every object in the heap, irrespective of whether it is
5554 tagged or not.
5555 <p/>
5556 During the execution of this function the state of the heap
5557 does not change: no objects are allocated, no objects are
5558 garbage collected, and the state of objects (including
5559 held values) does not change.
5560 As a result, threads executing Java
5561 programming language code, threads attempting to resume the
5562 execution of Java programming language code, and threads
5563 attempting to execute JNI functions are typically stalled.
5564 </description>
5565 <origin>new</origin>
5566 <capabilities>
5567 <required id="can_tag_objects"></required>
5568 </capabilities>
5569 <parameters>
5570 <param id="object_filter">
5571 <enum>jvmtiHeapObjectFilter</enum>
5572 <description>
5573 Indicates the objects for which the callback function is called.
5574 </description>
5575 </param>
5576 <param id="heap_object_callback">
5577 <ptrtype>
5578 <struct>jvmtiHeapObjectCallback</struct>
5579 </ptrtype>
5580 <description>
5581 The iterator function to be called for each
5582 object matching the <paramlink id="object_filter"/>.
5583 </description>
5584 </param>
5585 <param id="user_data">
5586 <inbuf>
5587 <void/>
5588 <nullok><code>NULL</code> is passed as the user supplied data</nullok>
5589 </inbuf>
5590 <description>
5591 User supplied data to be passed to the callback.
5592 </description>
5593 </param>
5594 </parameters>
5595 <errors>
5596 </errors>
5597 </function>
5598
5599 <function id="IterateOverInstancesOfClass" num="112">
5600 <synopsis>Iterate Over Instances Of Class</synopsis>
5601 <description>
5602 Iterate over all objects in the heap that are instances of the specified class.
5603 This includes direct instances of the specified class and
5604 instances of all subclasses of the specified class.
5605 This includes both reachable and unreachable objects.
5606 <p/>
5607 The <paramlink id="object_filter"></paramlink> parameter indicates the
5608 objects for which the callback function is called. If this parameter
5609 is <code>JVMTI_HEAP_OBJECT_TAGGED</code> then the callback will only be
5610 called for every object that is tagged. If the parameter is
5611 <code>JVMTI_HEAP_OBJECT_UNTAGGED</code> then the callback will only be
5612 called for objects that are not tagged. If the parameter
5613 is <code>JVMTI_HEAP_OBJECT_EITHER</code> then the callback will be
5614 called for every object in the heap, irrespective of whether it is
5615 tagged or not.
5616 <p/>
5617 During the execution of this function the state of the heap
5618 does not change: no objects are allocated, no objects are
5619 garbage collected, and the state of objects (including
5620 held values) does not change.
5621 As a result, threads executing Java
5622 programming language code, threads attempting to resume the
5623 execution of Java programming language code, and threads
5624 attempting to execute JNI functions are typically stalled.
5625 </description>
5626 <origin>new</origin>
5627 <capabilities>
5628 <required id="can_tag_objects"></required>
5629 </capabilities>
5630 <parameters>
5631 <param id="klass">
5632 <jclass/>
5633 <description>
5634 Iterate over objects of this class only.
5635 </description>
5636 </param>
5637 <param id="object_filter">
5638 <enum>jvmtiHeapObjectFilter</enum>
5639 <description>
5640 Indicates the objects for which the callback function is called.
5641 </description>
5642 </param>
5643 <param id="heap_object_callback">
5644 <ptrtype>
5645 <struct>jvmtiHeapObjectCallback</struct>
5646 </ptrtype>
5647 <description>
5648 The iterator function to be called for each
5649 <paramlink id="klass"/> instance matching
5650 the <paramlink id="object_filter"/>.
5651 </description>
5652 </param>
5653 <param id="user_data">
5654 <inbuf>
5655 <void/>
5656 <nullok><code>NULL</code> is passed as the user supplied data</nullok>
5657 </inbuf>
5658 <description>
5659 User supplied data to be passed to the callback.
5660 </description>
5661 </param>
5662 </parameters>
5663 <errors>
5664 </errors>
5665 </function>
5666
5667 </category>
5668
5669 <category id="local" label="Local Variable">
5670
5671 <intro>
5672 These functions are used to retrieve or set the value of a local variable.
5673 The variable is identified by the depth of the frame containing its
5674 value and the variable's slot number within that frame.
5675 The mapping of variables to
5676 slot numbers can be obtained with the function
5677 <functionlink id="GetLocalVariableTable"></functionlink>.
5678 </intro>
5679
5680 <function id="GetLocalObject" num="21">
5681 <synopsis>Get Local Variable - Object</synopsis>
5682 <description>
5683 This function can be used to retrieve the value of a local
5684 variable whose type is <code>Object</code> or a subclass of <code>Object</code>.
5685 </description>
5686 <origin>jvmdi</origin>
5687 <capabilities>
5688 <required id="can_access_local_variables"></required>
5689 </capabilities>
5690 <parameters>
5691 <param id="thread">
5692 <jthread null="current" frame="frame"/>
5693 <description>
5694 The thread of the frame containing the variable's value.
5695 </description>
5696 </param>
5697 <param id="depth">
5698 <jframeID thread="thread"/>
5699 <description>
5700 The depth of the frame containing the variable's value.
5701 </description>
5702 </param>
5703 <param id="slot">
5704 <jint/>
5705 <description>
5706 The variable's slot number.
5707 </description>
5708 </param>
5709 <param id="value_ptr">
5710 <outptr><jobject/></outptr>
5711 <description>
5712 On return, points to the variable's value.
5713 </description>
5714 </param>
5715 </parameters>
5716 <errors>
5717 <error id="JVMTI_ERROR_INVALID_SLOT">
5718 Invalid <code>slot</code>.
5719 </error>
5720 <error id="JVMTI_ERROR_TYPE_MISMATCH">
5721 The variable type is not
5722 <code>Object</code> or a subclass of <code>Object</code>.
5723 </error>
5724 <error id="JVMTI_ERROR_OPAQUE_FRAME">
5725 Not a visible frame
5726 </error>
5727 </errors>
5728 </function>
5729
5730 <function id="GetLocalInstance" num="155" since="1.2">
5731 <synopsis>Get Local Instance</synopsis>
5732 <description>
5733 This function can be used to retrieve the value of the local object
5734 variable at slot 0 (the "<code>this</code>" object) from non-static
5735 frames. This function can retrieve the "<code>this</code>" object from
5736 native method frames, whereas <code>GetLocalObject()</code> would
5737 return <code>JVMTI_ERROR_OPAQUE_FRAME</code> in those cases.
5738 </description>
5739 <origin>new</origin>
5740 <capabilities>
5741 <required id="can_access_local_variables"></required>
5742 </capabilities>
5743 <parameters>
5744 <param id="thread">
5745 <jthread null="current" frame="frame"/>
5746 <description>
5747 The thread of the frame containing the variable's value.
5748 </description>
5749 </param>
5750 <param id="depth">
5751 <jframeID thread="thread"/>
5752 <description>
5753 The depth of the frame containing the variable's value.
5754 </description>
5755 </param>
5756 <param id="value_ptr">
5757 <outptr><jobject/></outptr>
5758 <description>
5759 On return, points to the variable's value.
5760 </description>
5761 </param>
5762 </parameters>
5763 <errors>
5764 <error id="JVMTI_ERROR_INVALID_SLOT">
5765 If the specified frame is a static method frame.
5766 </error>
5767 </errors>
5768 </function>
5769 <function id="GetLocalInt" num="22">
5770 <synopsis>Get Local Variable - Int</synopsis>
5771 <description>
5772 This function can be used to retrieve the value of a local
5773 variable whose type is <code>int</code>,
5774 <code>short</code>, <code>char</code>, <code>byte</code>, or
5775 <code>boolean</code>.
5776 </description>
5777 <origin>jvmdi</origin>
5778 <capabilities>
5779 <required id="can_access_local_variables"></required>
5780 </capabilities>
5781 <parameters>
5782 <param id="thread">
5783 <jthread null="current" frame="frame"/>
5784 <description>
5785 The thread of the frame containing the variable's value.
5786 </description>
5787 </param>
5788 <param id="depth">
5789 <jframeID thread="thread"/>
5790 <description>
5791 The depth of the frame containing the variable's value.
5792 </description>
5793 </param>
5794 <param id="slot">
5795 <jint/>
5796 <description>
5797 The variable's slot number.
5798 </description>
5799 </param>
5800 <param id="value_ptr">
5801 <outptr><jint/></outptr>
5802 <description>
5803 On return, points to the variable's value.
5804 </description>
5805 </param>
5806 </parameters>
5807 <errors>
5808 <error id="JVMTI_ERROR_INVALID_SLOT">
5809 Invalid <code>slot</code>.
5810 </error>
5811 <error id="JVMTI_ERROR_TYPE_MISMATCH">
5812 The variable type is not
5813 <code>int</code>, <code>short</code>,
5814 <code>char</code>, <code>byte</code>, or
5815 <code>boolean</code>.
5816 </error>
5817 <error id="JVMTI_ERROR_OPAQUE_FRAME">
5818 Not a visible frame
5819 </error>
5820 </errors>
5821 </function>
5822
5823 <function id="GetLocalLong" num="23">
5824 <synopsis>Get Local Variable - Long</synopsis>
5825 <description>
5826 This function can be used to retrieve the value of a local
5827 variable whose type is <code>long</code>.
5828 </description>
5829 <origin>jvmdi</origin>
5830 <capabilities>
5831 <required id="can_access_local_variables"></required>
5832 </capabilities>
5833 <parameters>
5834 <param id="thread">
5835 <jthread null="current" frame="frame"/>
5836 <description>
5837 The thread of the frame containing the variable's value.
5838 </description>
5839 </param>
5840 <param id="depth">
5841 <jframeID thread="thread"/>
5842 <description>
5843 The depth of the frame containing the variable's value.
5844 </description>
5845 </param>
5846 <param id="slot">
5847 <jint/>
5848 <description>
5849 The variable's slot number.
5850 </description>
5851 </param>
5852 <param id="value_ptr">
5853 <outptr><jlong/></outptr>
5854 <description>
5855 On return, points to the variable's value.
5856 </description>
5857 </param>
5858 </parameters>
5859 <errors>
5860 <error id="JVMTI_ERROR_INVALID_SLOT">
5861 Invalid <code>slot</code>.
5862 </error>
5863 <error id="JVMTI_ERROR_TYPE_MISMATCH">
5864 The variable type is not <code>long</code>.
5865 </error>
5866 <error id="JVMTI_ERROR_OPAQUE_FRAME">
5867 Not a visible frame
5868 </error>
5869 </errors>
5870 </function>
5871
5872 <function id="GetLocalFloat" num="24">
5873 <synopsis>Get Local Variable - Float</synopsis>
5874 <description>
5875 This function can be used to retrieve the value of a local
5876 variable whose type is <code>float</code>.
5877 </description>
5878 <origin>jvmdi</origin>
5879 <capabilities>
5880 <required id="can_access_local_variables"></required>
5881 </capabilities>
5882 <parameters>
5883 <param id="thread">
5884 <jthread null="current" frame="frame"/>
5885 <description>
5886 The thread of the frame containing the variable's value.
5887 </description>
5888 </param>
5889 <param id="depth">
5890 <jframeID thread="thread"/>
5891 <description>
5892 The depth of the frame containing the variable's value.
5893 </description>
5894 </param>
5895 <param id="slot">
5896 <jint/>
5897 <description>
5898 The variable's slot number.
5899 </description>
5900 </param>
5901 <param id="value_ptr">
5902 <outptr><jfloat/></outptr>
5903 <description>
5904 On return, points to the variable's value.
5905 </description>
5906 </param>
5907 </parameters>
5908 <errors>
5909 <error id="JVMTI_ERROR_INVALID_SLOT">
5910 Invalid <code>slot</code>.
5911 </error>
5912 <error id="JVMTI_ERROR_TYPE_MISMATCH">
5913 The variable type is not <code>float</code>.
5914 </error>
5915 <error id="JVMTI_ERROR_OPAQUE_FRAME">
5916 Not a visible frame
5917 </error>
5918 </errors>
5919 </function>
5920
5921 <function id="GetLocalDouble" num="25">
5922 <synopsis>Get Local Variable - Double</synopsis>
5923 <description>
5924 This function can be used to retrieve the value of a local
5925 variable whose type is <code>long</code>.
5926 </description>
5927 <origin>jvmdi</origin>
5928 <capabilities>
5929 <required id="can_access_local_variables"></required>
5930 </capabilities>
5931 <parameters>
5932 <param id="thread">
5933 <jthread null="current" frame="frame"/>
5934 <description>
5935 The thread of the frame containing the variable's value.
5936 </description>
5937 </param>
5938 <param id="depth">
5939 <jframeID thread="thread"/>
5940 <description>
5941 The depth of the frame containing the variable's value.
5942 </description>
5943 </param>
5944 <param id="slot">
5945 <jint/>
5946 <description>
5947 The variable's slot number.
5948 </description>
5949 </param>
5950 <param id="value_ptr">
5951 <outptr><jdouble/></outptr>
5952 <description>
5953 On return, points to the variable's value.
5954 </description>
5955 </param>
5956 </parameters>
5957 <errors>
5958 <error id="JVMTI_ERROR_INVALID_SLOT">
5959 Invalid <code>slot</code>.
5960 </error>
5961 <error id="JVMTI_ERROR_TYPE_MISMATCH">
5962 The variable type is not <code>double</code>.
5963 </error>
5964 <error id="JVMTI_ERROR_OPAQUE_FRAME">
5965 Not a visible frame
5966 </error>
5967 </errors>
5968 </function>
5969
5970 <function id="SetLocalObject" num="26">
5971 <synopsis>Set Local Variable - Object</synopsis>
5972 <description>
5973 This function can be used to set the value of a local
5974 variable whose type is <code>Object</code> or a subclass of <code>Object</code>.
5975 </description>
5976 <origin>jvmdi</origin>
5977 <capabilities>
5978 <required id="can_access_local_variables"></required>
5979 </capabilities>
5980 <parameters>
5981 <param id="thread">
5982 <jthread null="current" frame="frame"/>
5983 <description>
5984 The thread of the frame containing the variable's value.
5985 </description>
5986 </param>
5987 <param id="depth">
5988 <jframeID thread="thread"/>
5989 <description>
5990 The depth of the frame containing the variable's value.
5991 </description>
5992 </param>
5993 <param id="slot">
5994 <jint/>
5995 <description>
5996 The variable's slot number.
5997 </description>
5998 </param>
5999 <param id="value">
6000 <jobject/>
6001 <description>
6002 The new value for the variable.
6003 </description>
6004 </param>
6005 </parameters>
6006 <errors>
6007 <error id="JVMTI_ERROR_INVALID_SLOT">
6008 Invalid <code>slot</code>.
6009 </error>
6010 <error id="JVMTI_ERROR_TYPE_MISMATCH">
6011 The variable type is not
6012 <code>Object</code> or a subclass of <code>Object</code>.
6013 </error>
6014 <error id="JVMTI_ERROR_TYPE_MISMATCH">
6015 The supplied <paramlink id="value"/> is not compatible
6016 with the variable type.
6017 </error>
6018 <error id="JVMTI_ERROR_OPAQUE_FRAME">
6019 Not a visible frame
6020 </error>
6021 </errors>
6022 </function>
6023
6024 <function id="SetLocalInt" num="27">
6025 <synopsis>Set Local Variable - Int</synopsis>
6026 <description>
6027 This function can be used to set the value of a local
6028 variable whose type is <code>int</code>,
6029 <code>short</code>, <code>char</code>, <code>byte</code>, or
6030 <code>boolean</code>.
6031 </description>
6032 <origin>jvmdi</origin>
6033 <capabilities>
6034 <required id="can_access_local_variables"></required>
6035 </capabilities>
6036 <parameters>
6037 <param id="thread">
6038 <jthread null="current" frame="frame"/>
6039 <description>
6040 The thread of the frame containing the variable's value.
6041 </description>
6042 </param>
6043 <param id="depth">
6044 <jframeID thread="thread"/>
6045 <description>
6046 The depth of the frame containing the variable's value.
6047 </description>
6048 </param>
6049 <param id="slot">
6050 <jint/>
6051 <description>
6052 The variable's slot number.
6053 </description>
6054 </param>
6055 <param id="value">
6056 <jint/>
6057 <description>
6058 The new value for the variable.
6059 </description>
6060 </param>
6061 </parameters>
6062 <errors>
6063 <error id="JVMTI_ERROR_INVALID_SLOT">
6064 Invalid <code>slot</code>.
6065 </error>
6066 <error id="JVMTI_ERROR_TYPE_MISMATCH">
6067 The variable type is not
6068 <code>int</code>, <code>short</code>,
6069 <code>char</code>, <code>byte</code>, or
6070 <code>boolean</code>.
6071 </error>
6072 <error id="JVMTI_ERROR_OPAQUE_FRAME">
6073 Not a visible frame
6074 </error>
6075 </errors>
6076 </function>
6077
6078 <function id="SetLocalLong" num="28">
6079 <synopsis>Set Local Variable - Long</synopsis>
6080 <description>
6081 This function can be used to set the value of a local
6082 variable whose type is <code>long</code>.
6083 </description>
6084 <origin>jvmdi</origin>
6085 <capabilities>
6086 <required id="can_access_local_variables"></required>
6087 </capabilities>
6088 <parameters>
6089 <param id="thread">
6090 <jthread null="current" frame="frame"/>
6091 <description>
6092 The thread of the frame containing the variable's value.
6093 </description>
6094 </param>
6095 <param id="depth">
6096 <jframeID thread="thread"/>
6097 <description>
6098 The depth of the frame containing the variable's value.
6099 </description>
6100 </param>
6101 <param id="slot">
6102 <jint/>
6103 <description>
6104 The variable's slot number.
6105 </description>
6106 </param>
6107 <param id="value">
6108 <jlong/>
6109 <description>
6110 The new value for the variable.
6111 </description>
6112 </param>
6113 </parameters>
6114 <errors>
6115 <error id="JVMTI_ERROR_INVALID_SLOT">
6116 Invalid <code>slot</code>.
6117 </error>
6118 <error id="JVMTI_ERROR_TYPE_MISMATCH">
6119 The variable type is not <code>long</code>.
6120 </error>
6121 <error id="JVMTI_ERROR_OPAQUE_FRAME">
6122 Not a visible frame
6123 </error>
6124 </errors>
6125 </function>
6126
6127 <function id="SetLocalFloat" num="29">
6128 <synopsis>Set Local Variable - Float</synopsis>
6129 <description>
6130 This function can be used to set the value of a local
6131 variable whose type is <code>float</code>.
6132 </description>
6133 <origin>jvmdi</origin>
6134 <capabilities>
6135 <required id="can_access_local_variables"></required>
6136 </capabilities>
6137 <parameters>
6138 <param id="thread">
6139 <jthread null="current" frame="frame"/>
6140 <description>
6141 The thread of the frame containing the variable's value.
6142 </description>
6143 </param>
6144 <param id="depth">
6145 <jframeID thread="thread"/>
6146 <description>
6147 The depth of the frame containing the variable's value.
6148 </description>
6149 </param>
6150 <param id="slot">
6151 <jint/>
6152 <description>
6153 The variable's slot number.
6154 </description>
6155 </param>
6156 <param id="value">
6157 <jfloat/>
6158 <description>
6159 The new value for the variable.
6160 </description>
6161 </param>
6162 </parameters>
6163 <errors>
6164 <error id="JVMTI_ERROR_INVALID_SLOT">
6165 Invalid <code>slot</code>.
6166 </error>
6167 <error id="JVMTI_ERROR_TYPE_MISMATCH">
6168 The variable type is not <code>float</code>.
6169 </error>
6170 <error id="JVMTI_ERROR_OPAQUE_FRAME">
6171 Not a visible frame
6172 </error>
6173 </errors>
6174 </function>
6175
6176 <function id="SetLocalDouble" num="30">
6177 <synopsis>Set Local Variable - Double</synopsis>
6178 <description>
6179 This function can be used to set the value of a local
6180 variable whose type is <code>double</code>.
6181 </description>
6182 <origin>jvmdi</origin>
6183 <capabilities>
6184 <required id="can_access_local_variables"></required>
6185 </capabilities>
6186 <parameters>
6187 <param id="thread">
6188 <jthread null="current" frame="frame"/>
6189 <description>
6190 The thread of the frame containing the variable's value.
6191 </description>
6192 </param>
6193 <param id="depth">
6194 <jframeID thread="thread"/>
6195 <description>
6196 The depth of the frame containing the variable's value.
6197 </description>
6198 </param>
6199 <param id="slot">
6200 <jint/>
6201 <description>
6202 The variable's slot number.
6203 </description>
6204 </param>
6205 <param id="value">
6206 <jdouble/>
6207 <description>
6208 The new value for the variable.
6209 </description>
6210 </param>
6211 </parameters>
6212 <errors>
6213 <error id="JVMTI_ERROR_INVALID_SLOT">
6214 Invalid <code>slot</code>.
6215 </error>
6216 <error id="JVMTI_ERROR_TYPE_MISMATCH">
6217 The variable type is not <code>double</code>.
6218 </error>
6219 <error id="JVMTI_ERROR_OPAQUE_FRAME">
6220 Not a visible frame
6221 </error>
6222 </errors>
6223 </function>
6224 </category>
6225
6226 <category id="breakpointCategory" label="Breakpoint">
6227
6228 <intro>
6229 </intro>
6230
6231 <function id="SetBreakpoint" num="38">
6232 <synopsis>Set Breakpoint</synopsis>
6233 <description>
6234 Set a breakpoint at the instruction indicated by
6235 <code>method</code> and <code>location</code>.
6236 An instruction can only have one breakpoint.
6237 <p/>
6238 Whenever the designated instruction is about to be executed, a
6239 <eventlink id="Breakpoint"></eventlink> event is generated.
6240 </description>
6241 <origin>jvmdi</origin>
6242 <capabilities>
6243 <required id="can_generate_breakpoint_events"></required>
6244 </capabilities>
6245 <parameters>
6246 <param id="klass">
6247 <jclass method="method"/>
6248 <description>
6249 The class in which to set the breakpoint
6250 </description>
6251 </param>
6252 <param id="method">
6253 <jmethodID class="klass"/>
6254 <description>
6255 The method in which to set the breakpoint
6256 </description>
6257 </param>
6258 <param id="location">
6259 <jlocation/>
6260 <description>
6261 the index of the instruction at which to set the breakpoint
6262
6263 </description>
6264 </param>
6265 </parameters>
6266 <errors>
6267 <error id="JVMTI_ERROR_DUPLICATE">
6268 The designated bytecode already has a breakpoint.
6269 </error>
6270 </errors>
6271 </function>
6272
6273 <function id="ClearBreakpoint" num="39">
6274 <synopsis>Clear Breakpoint</synopsis>
6275 <description>
6276 Clear the breakpoint at the bytecode indicated by
6277 <code>method</code> and <code>location</code>.
6278 </description>
6279 <origin>jvmdi</origin>
6280 <capabilities>
6281 <required id="can_generate_breakpoint_events"></required>
6282 </capabilities>
6283 <parameters>
6284 <param id="klass">
6285 <jclass method="method"/>
6286 <description>
6287 The class in which to clear the breakpoint
6288 </description>
6289 </param>
6290 <param id="method">
6291 <jmethodID class="klass"/>
6292 <description>
6293 The method in which to clear the breakpoint
6294 </description>
6295 </param>
6296 <param id="location">
6297 <jlocation/>
6298 <description>
6299 the index of the instruction at which to clear the breakpoint
6300 </description>
6301 </param>
6302 </parameters>
6303 <errors>
6304 <error id="JVMTI_ERROR_NOT_FOUND">
6305 There's no breakpoint at the designated bytecode.
6306 </error>
6307 </errors>
6308 </function>
6309
6310 </category>
6311
6312 <category id="fieldWatch" label="Watched Field">
6313
6314 <intro>
6315 </intro>
6316
6317 <function id="SetFieldAccessWatch" num="41">
6318 <synopsis>Set Field Access Watch</synopsis>
6319 <description>
6320 Generate a <eventlink id="FieldAccess"></eventlink> event
6321 when the field specified
6322 by <code>klass</code> and
6323 <code>field</code> is about to be accessed.
6324 An event will be generated for each access of the field
6325 until it is canceled with
6326 <functionlink id="ClearFieldAccessWatch"></functionlink>.
6327 Field accesses from Java programming language code or from JNI code are watched,
6328 fields modified by other means are not watched.
6329 Note that <jvmti/> users should be aware that their own field accesses
6330 will trigger the watch.
6331 A field can only have one field access watch set.
6332 Modification of a field is not considered an access--use
6333 <functionlink id="SetFieldModificationWatch"></functionlink>
6334 to monitor modifications.
6335 </description>
6336 <origin>jvmdi</origin>
6337 <capabilities>
6338 <required id="can_generate_field_access_events"></required>
6339 </capabilities>
6340 <parameters>
6341 <param id="klass">
6342 <jclass field="field"/>
6343 <description>
6344 The class containing the field to watch
6345 </description>
6346 </param>
6347 <param id="field">
6348 <jfieldID class="klass"/>
6349 <description>
6350 The field to watch
6351
6352 </description>
6353 </param>
6354 </parameters>
6355 <errors>
6356 <error id="JVMTI_ERROR_DUPLICATE">
6357 The designated field is already being watched for accesses.
6358 </error>
6359 </errors>
6360 </function>
6361
6362 <function id="ClearFieldAccessWatch" num="42">
6363 <synopsis>Clear Field Access Watch</synopsis>
6364 <description>
6365 Cancel a field access watch previously set by
6366 <functionlink id="SetFieldAccessWatch"></functionlink>, on the
6367 field specified
6368 by <code>klass</code> and
6369 <code>field</code>.
6370 </description>
6371 <origin>jvmdi</origin>
6372 <capabilities>
6373 <required id="can_generate_field_access_events"></required>
6374 </capabilities>
6375 <parameters>
6376 <param id="klass">
6377 <jclass field="field"/>
6378 <description>
6379 The class containing the field to watch
6380 </description>
6381 </param>
6382 <param id="field">
6383 <jfieldID class="klass"/>
6384 <description>
6385 The field to watch
6386
6387 </description>
6388 </param>
6389 </parameters>
6390 <errors>
6391 <error id="JVMTI_ERROR_NOT_FOUND">
6392 The designated field is not being watched for accesses.
6393 </error>
6394 </errors>
6395 </function>
6396
6397 <function id="SetFieldModificationWatch" num="43">
6398 <synopsis>Set Field Modification Watch</synopsis>
6399 <description>
6400 Generate a <eventlink id="FieldModification"></eventlink> event
6401 when the field specified
6402 by <code>klass</code> and
6403 <code>field</code> is about to be modified.
6404 An event will be generated for each modification of the field
6405 until it is canceled with
6406 <functionlink id="ClearFieldModificationWatch"></functionlink>.
6407 Field modifications from Java programming language code or from JNI code are watched,
6408 fields modified by other means are not watched.
6409 Note that <jvmti/> users should be aware that their own field modifications
6410 will trigger the watch.
6411 A field can only have one field modification watch set.
6412 </description>
6413 <origin>jvmdi</origin>
6414 <capabilities>
6415 <required id="can_generate_field_modification_events"></required>
6416 </capabilities>
6417 <parameters>
6418 <param id="klass">
6419 <jclass field="field"/>
6420 <description>
6421 The class containing the field to watch
6422 </description>
6423 </param>
6424 <param id="field">
6425 <jfieldID class="klass"/>
6426 <description>
6427 The field to watch
6428
6429 </description>
6430 </param>
6431 </parameters>
6432 <errors>
6433 <error id="JVMTI_ERROR_DUPLICATE">
6434 The designated field is already being watched for modifications.
6435 </error>
6436 </errors>
6437 </function>
6438
6439 <function id="ClearFieldModificationWatch" num="44">
6440 <synopsis>Clear Field Modification Watch</synopsis>
6441 <description>
6442
6443 Cancel a field modification watch previously set by
6444 <functionlink id="SetFieldModificationWatch"></functionlink>, on the
6445 field specified
6446 by <code>klass</code> and
6447 <code>field</code>.
6448 </description>
6449 <origin>jvmdi</origin>
6450 <capabilities>
6451 <required id="can_generate_field_modification_events"></required>
6452 </capabilities>
6453 <parameters>
6454 <param id="klass">
6455 <jclass field="field"/>
6456 <description>
6457 The class containing the field to watch
6458 </description>
6459 </param>
6460 <param id="field">
6461 <jfieldID class="klass"/>
6462 <description>
6463 The field to watch
6464
6465 </description>
6466 </param>
6467 </parameters>
6468 <errors>
6469 <error id="JVMTI_ERROR_NOT_FOUND">
6470 The designated field is not being watched for modifications.
6471 </error>
6472 </errors>
6473 </function>
6474 </category>
6475
6476 <category id="module" label="Module">
6477
6478 <intro>
6479 </intro>
6480
6481 <function id="GetAllModules" num="3" since="9">
6482 <synopsis>Get All Modules</synopsis>
6483 <description>
6484 Return an array of all modules loaded in the virtual machine.
6485 The number of modules in the array is returned via
6486 <code>module_count_ptr</code>, and the array itself via
6487 <code>modules_ptr</code>.
6488 <p/>
6489 </description>
6490 <origin>new</origin>
6491 <capabilities>
6492 </capabilities>
6493 <parameters>
6494 <param id="module_count_ptr">
6495 <outptr><jint/></outptr>
6496 <description>
6497 On return, points to the number of returned modules.
6498 </description>
6499 </param>
6500 <param id="modules_ptr">
6501 <allocbuf outcount="module_count_ptr"><jobject/></allocbuf>
6502 <description>
6503 On return, points to an array of references, one
6504 for each module.
6505 </description>
6506 </param>
6507 </parameters>
6508 <errors>
6509 </errors>
6510 </function>
6511 </category>
6512
6513 <category id="class" label="Class">
6514
6515 <intro>
6516 </intro>
6517
6518 <function id="GetLoadedClasses" jkernel="yes" num="78">
6519 <synopsis>Get Loaded Classes</synopsis>
6520 <description>
6521 Return an array of all classes loaded in the virtual machine.
6522 The number of classes in the array is returned via
6523 <code>class_count_ptr</code>, and the array itself via
6524 <code>classes_ptr</code>.
6525 <p/>
6526 Array classes of all types (including arrays of primitive types) are
6527 included in the returned list. Primitive classes (for example,
6528 <code>java.lang.Integer.TYPE</code>) are <i>not</i> included in this list.
6529 </description>
6530 <origin>jvmdi</origin>
6531 <capabilities>
6532 </capabilities>
6533 <parameters>
6534 <param id="class_count_ptr">
6535 <outptr><jint/></outptr>
6536 <description>
6537 On return, points to the number of classes.
6538 </description>
6539 </param>
6540 <param id="classes_ptr">
6541 <allocbuf outcount="class_count_ptr"><jclass/></allocbuf>
6542 <description>
6543 On return, points to an array of references, one
6544 for each class.
6545 </description>
6546 </param>
6547 </parameters>
6548 <errors>
6549 </errors>
6550 </function>
6551
6552 <function id="GetClassLoaderClasses" jkernel="yes" num="79">
6553 <synopsis>Get Classloader Classes</synopsis>
6554 <description>
6555 Returns an array of those classes for which this class loader has
6556 been recorded as an initiating loader. Each
6557 class in the returned array was created by this class loader,
6558 either by defining it directly or by delegation to another class loader.
6559 See <vmspec chapter="5.3"/>.
6560 <p/>
6561 The number of classes in the array is returned via
6562 <code>class_count_ptr</code>, and the array itself via
6563 <code>classes_ptr</code>.
6564 </description>
6565 <origin>jvmdi</origin>
6566 <capabilities>
6567 </capabilities>
6568 <parameters>
6569 <param id="initiating_loader">
6570 <ptrtype>
6571 <jobject/>
6572 <nullok>the classes initiated by the bootstrap loader will be returned</nullok>
6573 </ptrtype>
6574 <description>
6575 An initiating class loader.
6576 </description>
6577 </param>
6578 <param id="class_count_ptr">
6579 <outptr><jint/></outptr>
6580 <description>
6581 On return, points to the number of classes.
6582 </description>
6583 </param>
6584 <param id="classes_ptr">
6585 <allocbuf outcount="class_count_ptr"><jclass/></allocbuf>
6586 <description>
6587 On return, points to an array of references, one
6588 for each class.
6589 </description>
6590 </param>
6591 </parameters>
6592 <errors>
6593 </errors>
6594 </function>
6595
6596 <function id="GetClassSignature" phase="start" num="48">
6597 <synopsis>Get Class Signature</synopsis>
6598 <description>
6599 For the class indicated by <code>klass</code>, return the
6600 <externallink id="http://docs.oracle.com/javase/7/docs/technotes/guides/jni/spec/types.html#wp16432">JNI
6601 type signature</externallink>
6602 and the generic signature of the class.
6603 For example, <code>java.util.List</code> is <code>"Ljava/util/List;"</code>
6604 and <code>int[]</code> is <code>"[I"</code>
6605 The returned name for primitive classes
6606 is the type signature character of the corresponding primitive type.
6607 For example, <code>java.lang.Integer.TYPE</code> is <code>"I"</code>.
6608 </description>
6609 <origin>jvmdiClone</origin>
6610 <capabilities>
6611 </capabilities>
6612 <parameters>
6613 <param id="klass">
6614 <jclass/>
6615 <description>
6616 The class to query.
6617 </description>
6618 </param>
6619 <param id="signature_ptr">
6620 <allocbuf>
6621 <char/>
6622 <nullok>the signature is not returned</nullok>
6623 </allocbuf>
6624 <description>
6625 On return, points to the JNI type signature of the class, encoded as a
6626 <internallink id="mUTF">modified UTF-8</internallink> string.
6627 </description>
6628 </param>
6629 <param id="generic_ptr">
6630 <allocbuf>
6631 <char/>
6632 <nullok>the generic signature is not returned</nullok>
6633 </allocbuf>
6634 <description>
6635 On return, points to the generic signature of the class, encoded as a
6636 <internallink id="mUTF">modified UTF-8</internallink> string.
6637 If there is no generic signature attribute for the class, then,
6638 on return, points to <code>NULL</code>.
6639 </description>
6640 </param>
6641 </parameters>
6642 <errors>
6643 </errors>
6644 </function>
6645
6646 <function id="GetClassStatus" phase="start" num="49">
6647 <synopsis>Get Class Status</synopsis>
6648 <description>
6649 Get the status of the class. Zero or more of the following bits can be
6650 set.
6651 <constants id="jvmtiClassStatus" label="Class Status Flags" kind="bits">
6652 <constant id="JVMTI_CLASS_STATUS_VERIFIED" num="1">
6653 Class bytecodes have been verified
6654 </constant>
6655 <constant id="JVMTI_CLASS_STATUS_PREPARED" num="2">
6656 Class preparation is complete
6657 </constant>
6658 <constant id="JVMTI_CLASS_STATUS_INITIALIZED" num="4">
6659 Class initialization is complete. Static initializer has been run.
6660 </constant>
6661 <constant id="JVMTI_CLASS_STATUS_ERROR" num="8">
6662 Error during initialization makes class unusable
6663 </constant>
6664 <constant id="JVMTI_CLASS_STATUS_ARRAY" num="16">
6665 Class is an array. If set, all other bits are zero.
6666 </constant>
6667 <constant id="JVMTI_CLASS_STATUS_PRIMITIVE" num="32">
6668 Class is a primitive class (for example, <code>java.lang.Integer.TYPE</code>).
6669 If set, all other bits are zero.
6670 </constant>
6671 </constants>
6672 </description>
6673 <origin>jvmdi</origin>
6674 <capabilities>
6675 </capabilities>
6676 <parameters>
6677 <param id="klass">
6678 <jclass/>
6679 <description>
6680 The class to query.
6681 </description>
6682 </param>
6683 <param id="status_ptr">
6684 <outptr><jint/></outptr>
6685 <description>
6686 On return, points to the current state of this class as one or
6687 more of the <internallink id="jvmtiClassStatus">class status flags</internallink>.
6688 </description>
6689 </param>
6690 </parameters>
6691 <errors>
6692 </errors>
6693 </function>
6694
6695 <function id="GetSourceFileName" phase="start" num="50">
6696 <synopsis>Get Source File Name</synopsis>
6697 <description>
6698 For the class indicated by <code>klass</code>, return the source file
6699 name via <code>source_name_ptr</code>. The returned string
6700 is a file name only and never contains a directory name.
6701 <p/>
6702 For primitive classes (for example, <code>java.lang.Integer.TYPE</code>)
6703 and for arrays this function returns
6704 <errorlink id="JVMTI_ERROR_ABSENT_INFORMATION"></errorlink>.
6705 </description>
6706 <origin>jvmdi</origin>
6707 <capabilities>
6708 <required id="can_get_source_file_name"></required>
6709 </capabilities>
6710 <parameters>
6711 <param id="klass">
6712 <jclass/>
6713 <description>
6714 The class to query.
6715 </description>
6716 </param>
6717 <param id="source_name_ptr">
6718 <allocbuf><char/></allocbuf>
6719 <description>
6720 On return, points to the class's source file name, encoded as a
6721 <internallink id="mUTF">modified UTF-8</internallink> string.
6722 </description>
6723 </param>
6724 </parameters>
6725 <errors>
6726 <error id="JVMTI_ERROR_ABSENT_INFORMATION">
6727 Class information does not include a source file name. This includes
6728 cases where the class is an array class or primitive class.
6729 </error>
6730 </errors>
6731 </function>
6732
6733 <function id="GetClassModifiers" phase="start" num="51">
6734 <synopsis>Get Class Modifiers</synopsis>
6735 <description>
6736 For the class indicated by <code>klass</code>, return the access
6737 flags
6738 via <code>modifiers_ptr</code>.
6739 Access flags are defined in <vmspec chapter="4"/>.
6740 <p/>
6741 If the class is an array class, then its public, private, and protected
6742 modifiers are the same as those of its component type. For arrays of
6743 primitives, this component type is represented by one of the primitive
6744 classes (for example, <code>java.lang.Integer.TYPE</code>).
6745 <p/>
6746 If the class is a primitive class, its public modifier is always true,
6747 and its protected and private modifiers are always false.
6748 <p/>
6749 If the class is an array class or a primitive class then its final
6750 modifier is always true and its interface modifier is always false.
6751 The values of its other modifiers are not determined by this specification.
6752
6753 </description>
6754 <origin>jvmdi</origin>
6755 <capabilities>
6756 </capabilities>
6757 <parameters>
6758 <param id="klass">
6759 <jclass/>
6760 <description>
6761 The class to query.
6762 </description>
6763 </param>
6764 <param id="modifiers_ptr">
6765 <outptr><jint/></outptr>
6766 <description>
6767 On return, points to the current access flags of this class.
6768
6769 </description>
6770 </param>
6771 </parameters>
6772 <errors>
6773 </errors>
6774 </function>
6775
6776 <function id="GetClassMethods" phase="start" num="52">
6777 <synopsis>Get Class Methods</synopsis>
6778 <description>
6779 For the class indicated by <code>klass</code>, return a count of
6780 methods via <code>method_count_ptr</code> and a list of
6781 method IDs via <code>methods_ptr</code>. The method list contains
6782 constructors and static initializers as well as true methods.
6783 Only directly declared methods are returned (not inherited methods).
6784 An empty method list is returned for array classes and primitive classes
6785 (for example, <code>java.lang.Integer.TYPE</code>).
6786 </description>
6787 <origin>jvmdi</origin>
6788 <capabilities>
6789 <capability id="can_maintain_original_method_order"/>
6790 </capabilities>
6791 <parameters>
6792 <param id="klass">
6793 <jclass/>
6794 <description>
6795 The class to query.
6796 </description>
6797 </param>
6798 <param id="method_count_ptr">
6799 <outptr><jint/></outptr>
6800 <description>
6801 On return, points to the number of methods declared in this class.
6802 </description>
6803 </param>
6804 <param id="methods_ptr">
6805 <allocbuf outcount="method_count_ptr"><jmethodID class="klass"/></allocbuf>
6806 <description>
6807 On return, points to the method ID array.
6808 </description>
6809 </param>
6810 </parameters>
6811 <errors>
6812 <error id="JVMTI_ERROR_CLASS_NOT_PREPARED">
6813 <paramlink id="klass"></paramlink> is not prepared.
6814 </error>
6815 </errors>
6816 </function>
6817
6818 <function id="GetClassFields" phase="start" num="53">
6819 <synopsis>Get Class Fields</synopsis>
6820 <description>
6821 For the class indicated by <code>klass</code>, return a count of fields
6822 via <code>field_count_ptr</code> and a list of field IDs via
6823 <code>fields_ptr</code>.
6824 Only directly declared fields are returned (not inherited fields).
6825 Fields are returned in the order they occur in the class file.
6826 An empty field list is returned for array classes and primitive classes
6827 (for example, <code>java.lang.Integer.TYPE</code>).
6828 Use JNI to determine the length of an array.
6829 </description>
6830 <origin>jvmdi</origin>
6831 <capabilities>
6832 </capabilities>
6833 <parameters>
6834 <param id="klass">
6835 <jclass/>
6836 <description>
6837 The class to query.
6838 </description>
6839 </param>
6840 <param id="field_count_ptr">
6841 <outptr><jint/></outptr>
6842 <description>
6843 On return, points to the number of fields declared in this class.
6844 </description>
6845 </param>
6846 <param id="fields_ptr">
6847 <allocbuf outcount="field_count_ptr"><jfieldID/></allocbuf>
6848 <description>
6849 On return, points to the field ID array.
6850 </description>
6851 </param>
6852 </parameters>
6853 <errors>
6854 <error id="JVMTI_ERROR_CLASS_NOT_PREPARED">
6855 <paramlink id="klass"></paramlink> is not prepared.
6856 </error>
6857 </errors>
6858 </function>
6859
6860 <function id="GetImplementedInterfaces" phase="start" num="54">
6861 <synopsis>Get Implemented Interfaces</synopsis>
6862 <description>
6863 Return the direct super-interfaces of this class. For a class, this
6864 function returns the interfaces declared in its <code>implements</code>
6865 clause. For an interface, this function returns the interfaces declared in
6866 its <code>extends</code> clause.
6867 An empty interface list is returned for array classes and primitive classes
6868 (for example, <code>java.lang.Integer.TYPE</code>).
6869 </description>
6870 <origin>jvmdi</origin>
6871 <capabilities>
6872 </capabilities>
6873 <parameters>
6874 <param id="klass">
6875 <jclass/>
6876 <description>
6877 The class to query.
6878 </description>
6879 </param>
6880 <param id="interface_count_ptr">
6881 <outptr><jint/></outptr>
6882 <description>
6883 On return, points to the number of interfaces.
6884 </description>
6885 </param>
6886 <param id="interfaces_ptr">
6887 <allocbuf outcount="interface_count_ptr"><jclass/></allocbuf>
6888 <description>
6889 On return, points to the interface array.
6890 </description>
6891 </param>
6892 </parameters>
6893 <errors>
6894 <error id="JVMTI_ERROR_CLASS_NOT_PREPARED">
6895 <paramlink id="klass"></paramlink> is not prepared.
6896 </error>
6897 </errors>
6898 </function>
6899
6900 <function id="GetClassVersionNumbers" phase="start" num="145" since="1.1">
6901 <synopsis>Get Class Version Numbers</synopsis>
6902 <description>
6903 For the class indicated by <code>klass</code>,
6904 return the minor and major version numbers,
6905 as defined in
6906 <vmspec chapter="4"/>.
6907 </description>
6908 <origin>new</origin>
6909 <capabilities>
6910 </capabilities>
6911 <parameters>
6912 <param id="klass">
6913 <jclass/>
6914 <description>
6915 The class to query.
6916 </description>
6917 </param>
6918 <param id="minor_version_ptr">
6919 <outptr><jint/></outptr>
6920 <description>
6921 On return, points to the value of the
6922 <code>minor_version</code> item of the
6923 Class File Format.
6924 Note: to be consistent with the Class File Format,
6925 the minor version number is the first parameter.
6926 </description>
6927 </param>
6928 <param id="major_version_ptr">
6929 <outptr><jint/></outptr>
6930 <description>
6931 On return, points to the value of the
6932 <code>major_version</code> item of the
6933 Class File Format.
6934 </description>
6935 </param>
6936 </parameters>
6937 <errors>
6938 <error id="JVMTI_ERROR_ABSENT_INFORMATION">
6939 The class is a primitive or array class.
6940 </error>
6941 </errors>
6942 </function>
6943
6944 <function id="GetConstantPool" phase="start" num="146" since="1.1">
6945 <synopsis>Get Constant Pool</synopsis>
6946 <description>
6947 For the class indicated by <code>klass</code>,
6948 return the raw bytes of the constant pool in the format of the
6949 <code>constant_pool</code> item of
6950 <vmspec chapter="4"/>.
6951 The format of the constant pool may differ between versions
6952 of the Class File Format, so, the
6953 <functionlink id="GetClassVersionNumbers">minor and major
6954 class version numbers</functionlink> should be checked for
6955 compatibility.
6956 <p/>
6957 The returned constant pool might not have the same layout or
6958 contents as the constant pool in the defining class file.
6959 The constant pool returned by GetConstantPool() may have
6960 more or fewer entries than the defining constant pool.
6961 Entries may be in a different order.
6962 The constant pool returned by GetConstantPool() will match the
6963 constant pool used by
6964 <functionlink id="GetBytecodes">GetBytecodes()</functionlink>.
6965 That is, the bytecodes returned by GetBytecodes() will have
6966 constant pool indices which refer to constant pool entries returned
6967 by GetConstantPool().
6968 Note that since <functionlink id="RetransformClasses"/>
6969 and <functionlink id="RedefineClasses"/> can change
6970 the constant pool, the constant pool returned by this function
6971 can change accordingly. Thus, the correspondence between
6972 GetConstantPool() and GetBytecodes() does not hold if there
6973 is an intervening class retransformation or redefinition.
6974 The value of a constant pool entry used by a given bytecode will
6975 match that of the defining class file (even if the indices don't match).
6976 Constant pool entries which are not used directly or indirectly by
6977 bytecodes (for example, UTF-8 strings associated with annotations) are
6978 not required to exist in the returned constant pool.
6979 </description>
6980 <origin>new</origin>
6981 <capabilities>
6982 <required id="can_get_constant_pool"></required>
6983 </capabilities>
6984 <parameters>
6985 <param id="klass">
6986 <jclass/>
6987 <description>
6988 The class to query.
6989 </description>
6990 </param>
6991 <param id="constant_pool_count_ptr">
6992 <outptr><jint/></outptr>
6993 <description>
6994 On return, points to the number of entries
6995 in the constant pool table plus one.
6996 This corresponds to the <code>constant_pool_count</code>
6997 item of the Class File Format.
6998 </description>
6999 </param>
7000 <param id="constant_pool_byte_count_ptr">
7001 <outptr><jint/></outptr>
7002 <description>
7003 On return, points to the number of bytes
7004 in the returned raw constant pool.
7005 </description>
7006 </param>
7007 <param id="constant_pool_bytes_ptr">
7008 <allocbuf outcount="constant_pool_byte_count_ptr"><uchar/></allocbuf>
7009 <description>
7010 On return, points to the raw constant pool, that is the bytes
7011 defined by the <code>constant_pool</code> item of the
7012 Class File Format
7013 </description>
7014 </param>
7015 </parameters>
7016 <errors>
7017 <error id="JVMTI_ERROR_ABSENT_INFORMATION">
7018 The class is a primitive or array class.
7019 </error>
7020 </errors>
7021 </function>
7022
7023 <function id="IsInterface" phase="start" num="55">
7024 <synopsis>Is Interface</synopsis>
7025 <description>
7026 Determines whether a class object reference represents an interface.
7027 The <code>jboolean</code> result is
7028 <code>JNI_TRUE</code> if the "class" is actually an interface,
7029 <code>JNI_FALSE</code> otherwise.
7030 </description>
7031 <origin>jvmdi</origin>
7032 <capabilities>
7033 </capabilities>
7034 <parameters>
7035 <param id="klass">
7036 <jclass/>
7037 <description>
7038 The class to query.
7039 </description>
7040 </param>
7041 <param id="is_interface_ptr">
7042 <outptr><jboolean/></outptr>
7043 <description>
7044 On return, points to the boolean result of this function.
7045
7046 </description>
7047 </param>
7048 </parameters>
7049 <errors>
7050 </errors>
7051 </function>
7052
7053 <function id="IsArrayClass" phase="start" num="56">
7054 <synopsis>Is Array Class</synopsis>
7055 <description>
7056 Determines whether a class object reference represents an array.
7057 The <code>jboolean</code> result is
7058 <code>JNI_TRUE</code> if the class is an array,
7059 <code>JNI_FALSE</code> otherwise.
7060 </description>
7061 <origin>jvmdi</origin>
7062 <capabilities>
7063 </capabilities>
7064 <parameters>
7065 <param id="klass">
7066 <jclass/>
7067 <description>
7068 The class to query.
7069 </description>
7070 </param>
7071 <param id="is_array_class_ptr">
7072 <outptr><jboolean/></outptr>
7073 <description>
7074 On return, points to the boolean result of this function.
7075
7076 </description>
7077 </param>
7078 </parameters>
7079 <errors>
7080 </errors>
7081 </function>
7082
7083 <function id="IsModifiableClass" jkernel="yes" phase="start" num="45" since="1.1">
7084 <synopsis>Is Modifiable Class</synopsis>
7085 <description>
7086 Determines whether a class is modifiable.
7087 If a class is modifiable (<paramlink id="is_modifiable_class_ptr"/>
7088 returns <code>JNI_TRUE</code>) the class can be
7089 redefined with <functionlink id="RedefineClasses"/> (assuming
7090 the agent possesses the
7091 <fieldlink id="can_redefine_classes" struct="jvmtiCapabilities"/>
7092 capability) or
7093 retransformed with <functionlink id="RetransformClasses"/> (assuming
7094 the agent possesses the
7095 <fieldlink id="can_retransform_classes" struct="jvmtiCapabilities"/>
7096 capability).
7097 If a class is not modifiable (<paramlink id="is_modifiable_class_ptr"/>
7098 returns <code>JNI_FALSE</code>) the class can be neither
7099 redefined nor retransformed.
7100 <p/>
7101 Primitive classes (for example, <code>java.lang.Integer.TYPE</code>)
7102 and array classes are never modifiable.
7103 <p/>
7104 </description>
7105 <origin>new</origin>
7106 <capabilities>
7107 <capability id="can_redefine_any_class">
7108 If possessed then all classes (except primitive and array classes)
7109 are modifiable.
7110 </capability>
7111 <capability id="can_redefine_classes">
7112 No effect on the result of the function.
7113 But must additionally be possessed to modify the class with
7114 <functionlink id="RedefineClasses"/>.
7115 </capability>
7116 <capability id="can_retransform_classes">
7117 No effect on the result of the function.
7118 But must additionally be possessed to modify the class with
7119 <functionlink id="RetransformClasses"/>.
7120 </capability>
7121 </capabilities>
7122 <parameters>
7123 <param id="klass">
7124 <jclass/>
7125 <description>
7126 The class to query.
7127 </description>
7128 </param>
7129 <param id="is_modifiable_class_ptr">
7130 <outptr><jboolean/></outptr>
7131 <description>
7132 On return, points to the boolean result of this function.
7133 </description>
7134 </param>
7135 </parameters>
7136 <errors>
7137 </errors>
7138 </function>
7139
7140 <function id="GetClassLoader" phase="start" num="57">
7141 <synopsis>Get Class Loader</synopsis>
7142 <description>
7143 For the class indicated by <code>klass</code>, return via
7144 <code>classloader_ptr</code> a reference to the class loader for the
7145 class.
7146 </description>
7147 <origin>jvmdi</origin>
7148 <capabilities>
7149 </capabilities>
7150 <parameters>
7151 <param id="klass">
7152 <jclass/>
7153 <description>
7154 The class to query.
7155 </description>
7156 </param>
7157 <param id="classloader_ptr">
7158 <outptr><jobject/></outptr>
7159 <description>
7160 On return, points to the class loader that loaded
7161 this class.
7162 If the class was not created by a class loader
7163 or if the class loader is the bootstrap class loader,
7164 points to <code>NULL</code>.
7165 </description>
7166 </param>
7167 </parameters>
7168 <errors>
7169 </errors>
7170
7171 </function>
7172
7173 <function id="GetSourceDebugExtension" phase="start" num="90">
7174 <synopsis>Get Source Debug Extension</synopsis>
7175 <description>
7176 For the class indicated by <code>klass</code>, return the debug
7177 extension via <code>source_debug_extension_ptr</code>.
7178 The returned string
7179 contains exactly the debug extension information present in the
7180 class file of <code>klass</code>.
7181 </description>
7182 <origin>jvmdi</origin>
7183 <capabilities>
7184 <required id="can_get_source_debug_extension"></required>
7185 </capabilities>
7186 <parameters>
7187 <param id="klass">
7188 <jclass/>
7189 <description>
7190 The class to query.
7191 </description>
7192 </param>
7193 <param id="source_debug_extension_ptr">
7194 <allocbuf><char/></allocbuf>
7195 <description>
7196 On return, points to the class's debug extension, encoded as a
7197 <internallink id="mUTF">modified UTF-8</internallink> string.
7198 </description>
7199 </param>
7200 </parameters>
7201 <errors>
7202 <error id="JVMTI_ERROR_ABSENT_INFORMATION">
7203 Class information does not include a debug extension.
7204 </error>
7205 </errors>
7206 </function>
7207
7208 <function id="RetransformClasses" jkernel="yes" num="152" since="1.1">
7209 <synopsis>Retransform Classes</synopsis>
7210 <description>
7211 This function facilitates the
7212 <internallink id="bci">bytecode instrumentation</internallink>
7213 of already loaded classes.
7214 To replace the class definition without reference to the existing
7215 bytecodes, as one might do when recompiling from source for
7216 fix-and-continue debugging, <functionlink id="RedefineClasses"/>
7217 function should be used instead.
7218 <p/>
7219 When classes are initially loaded or when they are
7220 <functionlink id="RedefineClasses">redefined</functionlink>,
7221 the initial class file bytes can be transformed with the
7222 <eventlink id="ClassFileLoadHook"/> event.
7223 This function reruns the transformation process
7224 (whether or not a transformation has previously occurred).
7225 This retransformation follows these steps:
7226 <ul>
7227 <li>starting from the initial class file bytes
7228 </li>
7229 <li>for each <fieldlink id="can_retransform_classes"
7230 struct="jvmtiCapabilities">retransformation
7231 incapable</fieldlink>
7232 agent which received a
7233 <code>ClassFileLoadHook</code> event during the previous
7234 load or redefine, the bytes it returned
7235 (via the <code>new_class_data</code> parameter)
7236 are reused as the output of the transformation;
7237 note that this is equivalent to reapplying
7238 the previous transformation, unaltered. except that
7239 the <code>ClassFileLoadHook</code> event
7240 is <b>not</b> sent to these agents
7241 </li>
7242 <li>for each <fieldlink id="can_retransform_classes"
7243 struct="jvmtiCapabilities">retransformation
7244 capable</fieldlink>
7245 agent, the <code>ClassFileLoadHook</code> event is sent,
7246 allowing a new transformation to be applied
7247 </li>
7248 <li>the transformed class file bytes are installed as the new
7249 definition of the class
7250 </li>
7251 </ul>
7252 See the <eventlink id="ClassFileLoadHook"/> event for more details.
7253 <p/>
7254 The initial class file bytes represent the bytes passed to
7255 <code>ClassLoader.defineClass</code>
7256 or <code>RedefineClasses</code> (before any transformations
7257 were applied), however they may not exactly match them.
7258 The constant pool may differ in ways described in
7259 <functionlink id="GetConstantPool"/>.
7260 Constant pool indices in the bytecodes of methods will correspond.
7261 Some attributes may not be present.
7262 Where order is not meaningful, for example the order of methods,
7263 order may not be preserved.
7264 <p/>
7265 Retransformation can cause new versions of methods to be installed.
7266 Old method versions may become
7267 <internallink id="obsoleteMethods">obsolete</internallink>
7268 The new method version will be used on new invokes.
7269 If a method has active stack frames, those active frames continue to
7270 run the bytecodes of the original method version.
7271 <p/>
7272 This function does not cause any initialization except that which
7273 would occur under the customary JVM semantics.
7274 In other words, retransforming a class does not cause its initializers to be
7275 run. The values of static fields will remain as they were
7276 prior to the call.
7277 <p/>
7278 Threads need not be suspended.
7279 <p/>
7280 All breakpoints in the class are cleared.
7281 <p/>
7282 All attributes are updated.
7283 <p/>
7284 Instances of the retransformed class are not affected -- fields retain their
7285 previous values.
7286 <functionlink id="GetTag">Tags</functionlink> on the instances are
7287 also unaffected.
7288 <p/>
7289 In response to this call, no events other than the
7290 <eventlink id="ClassFileLoadHook"/> event
7291 will be sent.
7292 <p/>
7293 The retransformation may change method bodies, the constant pool and attributes.
7294 The retransformation must not add, remove or rename fields or methods, change the
7295 signatures of methods, change modifiers, or change inheritance.
7296 These restrictions may be lifted in future versions.
7297 See the error return description below for information on error codes
7298 returned if an unsupported retransformation is attempted.
7299 The class file bytes are not verified or installed until they have passed
7300 through the chain of <eventlink id="ClassFileLoadHook"/> events, thus the
7301 returned error code reflects the result of the transformations.
7302 If any error code is returned other than <code>JVMTI_ERROR_NONE</code>,
7303 none of the classes to be retransformed will have a new definition installed.
7304 When this function returns (with the error code of <code>JVMTI_ERROR_NONE</code>)
7305 all of the classes to be retransformed will have their new definitions installed.
7306 </description>
7307 <origin>new</origin>
7308 <capabilities>
7309 <required id="can_retransform_classes"></required>
7310 <capability id="can_retransform_any_class"></capability>
7311 </capabilities>
7312 <parameters>
7313 <param id="class_count">
7314 <jint min="0"/>
7315 <description>
7316 The number of classes to be retransformed.
7317 </description>
7318 </param>
7319 <param id="classes">
7320 <inbuf incount="class_count"><jclass/></inbuf>
7321 <description>
7322 The array of classes to be retransformed.
7323 </description>
7324 </param>
7325 </parameters>
7326 <errors>
7327 <error id="JVMTI_ERROR_UNMODIFIABLE_CLASS">
7328 One of the <paramlink id="classes"/> cannot be modified.
7329 See <functionlink id="IsModifiableClass"/>.
7330 </error>
7331 <error id="JVMTI_ERROR_INVALID_CLASS">
7332 One of the <paramlink id="classes"/> is not a valid class.
7333 </error>
7334 <error id="JVMTI_ERROR_UNSUPPORTED_VERSION">
7335 A retransformed class file has a version number not supported by this VM.
7336 </error>
7337 <error id="JVMTI_ERROR_INVALID_CLASS_FORMAT">
7338 A retransformed class file is malformed (The VM would return a <code>ClassFormatError</code>).
7339 </error>
7340 <error id="JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION">
7341 The retransformed class file definitions would lead to a circular definition
7342 (the VM would return a <code>ClassCircularityError</code>).
7343 </error>
7344 <error id="JVMTI_ERROR_FAILS_VERIFICATION">
7345 The retransformed class file bytes fail verification.
7346 </error>
7347 <error id="JVMTI_ERROR_NAMES_DONT_MATCH">
7348 The class name defined in a retransformed class file is
7349 different from the name in the old class object.
7350 </error>
7351 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED">
7352 A retransformed class file would require adding a method.
7353 </error>
7354 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED">
7355 A retransformed class file changes a field.
7356 </error>
7357 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED">
7358 A direct superclass is different for a retransformed class file,
7359 or the set of directly implemented
7360 interfaces is different.
7361 </error>
7362 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED">
7363 A retransformed class file does not declare a method
7364 declared in the old class version.
7365 </error>
7366 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED">
7367 A retransformed class file has different class modifiers.
7368 </error>
7369 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED">
7370 A method in the retransformed class file has different modifiers
7371 than its counterpart in the old class version.
7372 </error>
7373 </errors>
7374 </function>
7375
7376 <function id="RedefineClasses" jkernel="yes" num="87">
7377 <synopsis>Redefine Classes</synopsis>
7378 <typedef id="jvmtiClassDefinition" label="Class redefinition description">
7379 <field id="klass">
7380 <jclass/>
7381 <description>
7382 Class object for this class
7383 </description>
7384 </field>
7385 <field id="class_byte_count">
7386 <jint/>
7387 <description>
7388 Number of bytes defining class (below)
7389 </description>
7390 </field>
7391 <field id="class_bytes">
7392 <inbuf incount="class_byte_count"><uchar/></inbuf>
7393 <description>
7394 Bytes defining class (in <vmspec chapter="4"/>)
7395 </description>
7396 </field>
7397 </typedef>
7398 <description>
7399 All classes given are redefined according to the definitions
7400 supplied.
7401 This function is used to replace the definition of a class
7402 with a new definition, as might be needed in fix-and-continue
7403 debugging.
7404 Where the existing class file bytes are to be transformed, for
7405 example in
7406 <internallink id="bci">bytecode instrumentation</internallink>,
7407 <functionlink id="RetransformClasses"/> should be used.
7408 <p/>
7409 Redefinition can cause new versions of methods to be installed.
7410 Old method versions may become
7411 <internallink id="obsoleteMethods">obsolete</internallink>
7412 The new method version will be used on new invokes.
7413 If a method has active stack frames, those active frames continue to
7414 run the bytecodes of the original method version.
7415 If resetting of stack frames is desired, use
7416 <functionlink id="PopFrame"></functionlink>
7417 to pop frames with obsolete method versions.
7418 <p/>
7419 This function does not cause any initialization except that which
7420 would occur under the customary JVM semantics.
7421 In other words, redefining a class does not cause its initializers to be
7422 run. The values of static fields will remain as they were
7423 prior to the call.
7424 <p/>
7425 Threads need not be suspended.
7426 <p/>
7427 All breakpoints in the class are cleared.
7428 <p/>
7429 All attributes are updated.
7430 <p/>
7431 Instances of the redefined class are not affected -- fields retain their
7432 previous values.
7433 <functionlink id="GetTag">Tags</functionlink> on the instances are
7434 also unaffected.
7435 <p/>
7436 In response to this call, the <jvmti/> event
7437 <eventlink id="ClassFileLoadHook">Class File Load Hook</eventlink>
7438 will be sent (if enabled), but no other <jvmti/> events will be sent.
7439 <p/>
7440 The redefinition may change method bodies, the constant pool and attributes.
7441 The redefinition must not add, remove or rename fields or methods, change the
7442 signatures of methods, change modifiers, or change inheritance.
7443 These restrictions may be lifted in future versions.
7444 See the error return description below for information on error codes
7445 returned if an unsupported redefinition is attempted.
7446 The class file bytes are not verified or installed until they have passed
7447 through the chain of <eventlink id="ClassFileLoadHook"/> events, thus the
7448 returned error code reflects the result of the transformations applied
7449 to the bytes passed into <paramlink id="class_definitions"/>.
7450 If any error code is returned other than <code>JVMTI_ERROR_NONE</code>,
7451 none of the classes to be redefined will have a new definition installed.
7452 When this function returns (with the error code of <code>JVMTI_ERROR_NONE</code>)
7453 all of the classes to be redefined will have their new definitions installed.
7454 </description>
7455 <origin>jvmdi</origin>
7456 <capabilities>
7457 <required id="can_redefine_classes"></required>
7458 <capability id="can_redefine_any_class"></capability>
7459 </capabilities>
7460 <parameters>
7461 <param id="class_count">
7462 <jint min="0"/>
7463 <description>
7464 The number of classes specified in <code>class_definitions</code>
7465 </description>
7466 </param>
7467 <param id="class_definitions">
7468 <inbuf incount="class_count"><struct>jvmtiClassDefinition</struct></inbuf>
7469 <description>
7470 The array of new class definitions
7471 </description>
7472 </param>
7473 </parameters>
7474 <errors>
7475 <error id="JVMTI_ERROR_NULL_POINTER">
7476 One of <code>class_bytes</code> is <code>NULL</code>.
7477 </error>
7478 <error id="JVMTI_ERROR_UNMODIFIABLE_CLASS">
7479 An element of <code>class_definitions</code> cannot be modified.
7480 See <functionlink id="IsModifiableClass"/>.
7481 </error>
7482 <error id="JVMTI_ERROR_INVALID_CLASS">
7483 An element of <code>class_definitions</code> is not a valid class.
7484 </error>
7485 <error id="JVMTI_ERROR_UNSUPPORTED_VERSION">
7486 A new class file has a version number not supported by this VM.
7487 </error>
7488 <error id="JVMTI_ERROR_INVALID_CLASS_FORMAT">
7489 A new class file is malformed (The VM would return a <code>ClassFormatError</code>).
7490 </error>
7491 <error id="JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION">
7492 The new class file definitions would lead to a circular definition
7493 (the VM would return a <code>ClassCircularityError</code>).
7494 </error>
7495 <error id="JVMTI_ERROR_FAILS_VERIFICATION">
7496 The class bytes fail verification.
7497 </error>
7498 <error id="JVMTI_ERROR_NAMES_DONT_MATCH">
7499 The class name defined in a new class file is
7500 different from the name in the old class object.
7501 </error>
7502 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED">
7503 A new class file would require adding a method.
7504 </error>
7505 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED">
7506 A new class version changes a field.
7507 </error>
7508 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED">
7509 A direct superclass is different for a new class
7510 version, or the set of directly implemented
7511 interfaces is different.
7512 </error>
7513 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED">
7514 A new class version does not declare a method
7515 declared in the old class version.
7516 </error>
7517 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED">
7518 A new class version has different modifiers.
7519 </error>
7520 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED">
7521 A method in the new class version has different modifiers
7522 than its counterpart in the old class version.
7523 </error>
7524 </errors>
7525 </function>
7526
7527 </category>
7528
7529 <category id="object" label="Object">
7530
7531 <function id="GetObjectSize" jkernel="yes" phase="start" num="154">
7532 <synopsis>Get Object Size</synopsis>
7533 <description>
7534 For the object indicated by <code>object</code>,
7535 return via <code>size_ptr</code> the size of the object.
7536 This size is an implementation-specific approximation of
7537 the amount of storage consumed by this object.
7538 It may include some or all of the object's overhead, and thus
7539 is useful for comparison within an implementation but not
7540 between implementations.
7541 The estimate may change during a single invocation of the JVM.
7542 </description>
7543 <origin>new</origin>
7544 <capabilities>
7545 </capabilities>
7546 <parameters>
7547 <param id="object">
7548 <jobject/>
7549 <description>
7550 The object to query.
7551 </description>
7552 </param>
7553 <param id="size_ptr">
7554 <outptr><jlong/></outptr>
7555 <description>
7556 On return, points to the object's size in bytes.
7557 </description>
7558 </param>
7559 </parameters>
7560 <errors>
7561 </errors>
7562 </function>
7563
7564 <function id="GetObjectHashCode" phase="start" num="58">
7565 <synopsis>Get Object Hash Code</synopsis>
7566 <description>
7567 For the object indicated by <code>object</code>,
7568 return via <code>hash_code_ptr</code> a hash code.
7569 This hash code could be used to maintain a hash table of object references,
7570 however, on some implementations this can cause significant performance
7571 impacts--in most cases
7572 <internallink id="Heap">tags</internallink>
7573 will be a more efficient means of associating information with objects.
7574 This function guarantees
7575 the same hash code value for a particular object throughout its life
7576 </description>
7577 <origin>jvmdi</origin>
7578 <capabilities>
7579 </capabilities>
7580 <parameters>
7581 <param id="object">
7582 <jobject/>
7583 <description>
7584 The object to query.
7585 </description>
7586 </param>
7587 <param id="hash_code_ptr">
7588 <outptr><jint/></outptr>
7589 <description>
7590 On return, points to the object's hash code.
7591 </description>
7592 </param>
7593 </parameters>
7594 <errors>
7595 </errors>
7596 </function>
7597
7598 <function id="GetObjectMonitorUsage" num="59">
7599 <synopsis>Get Object Monitor Usage</synopsis>
7600 <typedef id="jvmtiMonitorUsage" label="Object monitor usage information">
7601 <field id="owner">
7602 <jthread/>
7603 <description>
7604 The thread owning this monitor, or <code>NULL</code> if unused
7605 </description>
7606 </field>
7607 <field id="entry_count">
7608 <jint/>
7609 <description>
7610 The number of times the owning thread has entered the monitor
7611 </description>
7612 </field>
7613 <field id="waiter_count">
7614 <jint/>
7615 <description>
7616 The number of threads waiting to own this monitor
7617 </description>
7618 </field>
7619 <field id="waiters">
7620 <allocfieldbuf><jthread/></allocfieldbuf>
7621 <description>
7622 The <code>waiter_count</code> waiting threads
7623 </description>
7624 </field>
7625 <field id="notify_waiter_count">
7626 <jint/>
7627 <description>
7628 The number of threads waiting to be notified by this monitor
7629 </description>
7630 </field>
7631 <field id="notify_waiters">
7632 <allocfieldbuf><jthread/></allocfieldbuf>
7633 <description>
7634 The <code>notify_waiter_count</code> threads waiting to be notified
7635 </description>
7636 </field>
7637 </typedef>
7638 <description>
7639 Get information about the object's monitor.
7640 The fields of the <functionlink id="jvmtiMonitorUsage"></functionlink> structure
7641 are filled in with information about usage of the monitor.
7642 <todo>
7643 Decide and then clarify suspend requirements.
7644 </todo>
7645 </description>
7646 <origin>jvmdi</origin>
7647 <capabilities>
7648 <required id="can_get_monitor_info"></required>
7649 </capabilities>
7650 <parameters>
7651 <param id="object">
7652 <jobject/>
7653 <description>
7654 The object to query.
7655 </description>
7656 </param>
7657 <param id="info_ptr">
7658 <outptr><struct>jvmtiMonitorUsage</struct></outptr>
7659 <description>
7660 On return, filled with monitor information for the
7661 specified object.
7662 </description>
7663 </param>
7664 </parameters>
7665 <errors>
7666 </errors>
7667 </function>
7668
7669 <elide>
7670 <function id="GetObjectMonitors" num="116">
7671 <synopsis>Get Object Monitors</synopsis>
7672 <description>
7673 Return the list of object monitors.
7674 <p/>
7675 Note: details about each monitor can be examined with
7676 <functionlink id="GetObjectMonitorUsage"></functionlink>.
7677 </description>
7678 <origin>new</origin>
7679 <capabilities>
7680 <required id="can_get_monitor_info"></required>
7681 </capabilities>
7682 <parameters>
7683 <param id="monitorCnt">
7684 <outptr><jint/></outptr>
7685 <description>
7686 On return, pointer to the number
7687 of monitors returned in <code>monitors_ptr</code>.
7688 </description>
7689 </param>
7690 <param id="monitors_ptr">
7691 <allocbuf outcount="monitorCnt"><jobject/></allocbuf>
7692 <description>
7693 On return, pointer to the monitor list.
7694 </description>
7695 </param>
7696 </parameters>
7697 <errors>
7698 </errors>
7699 </function>
7700 </elide>
7701
7702 </category>
7703
7704 <category id="fieldCategory" label="Field">
7705
7706 <intro>
7707 </intro>
7708
7709 <function id="GetFieldName" phase="start" num="60">
7710 <synopsis>Get Field Name (and Signature)</synopsis>
7711 <description>
7712 For the field indicated by <paramlink id="klass"/> and <paramlink id="field"/>,
7713 return the field name via <paramlink id="name_ptr"/> and field signature via
7714 <paramlink id="signature_ptr"/>.
7715 <p/>
7716 Field signatures are defined in the JNI Specification and
7717 are referred to as <code>field descriptors</code> in
7718 <vmspec chapter="4.3.2"/>.
7719 </description>
7720 <origin>jvmdiClone</origin>
7721 <capabilities>
7722 </capabilities>
7723 <parameters>
7724 <param id="klass">
7725 <jclass field="field"/>
7726 <description>
7727 The class of the field to query.
7728 </description>
7729 </param>
7730 <param id="field">
7731 <jfieldID class="klass"/>
7732 <description>
7733 The field to query.
7734 </description>
7735 </param>
7736 <param id="name_ptr">
7737 <allocbuf>
7738 <char/>
7739 <nullok>the name is not returned</nullok>
7740 </allocbuf>
7741 <description>
7742 On return, points to the field name, encoded as a
7743 <internallink id="mUTF">modified UTF-8</internallink> string.
7744 </description>
7745 </param>
7746 <param id="signature_ptr">
7747 <allocbuf>
7748 <char/>
7749 <nullok>the signature is not returned</nullok>
7750 </allocbuf>
7751 <description>
7752 On return, points to the field signature, encoded as a
7753 <internallink id="mUTF">modified UTF-8</internallink> string.
7754 </description>
7755 </param>
7756 <param id="generic_ptr">
7757 <allocbuf>
7758 <char/>
7759 <nullok>the generic signature is not returned</nullok>
7760 </allocbuf>
7761 <description>
7762 On return, points to the generic signature of the field, encoded as a
7763 <internallink id="mUTF">modified UTF-8</internallink> string.
7764 If there is no generic signature attribute for the field, then,
7765 on return, points to <code>NULL</code>.
7766 </description>
7767 </param>
7768 </parameters>
7769 <errors>
7770 </errors>
7771 </function>
7772
7773 <function id="GetFieldDeclaringClass" phase="start" num="61">
7774 <synopsis>Get Field Declaring Class</synopsis>
7775 <description>
7776 For the field indicated by <code>klass</code> and <code>field</code>
7777 return the class that defined it via <code>declaring_class_ptr</code>.
7778 The declaring class will either be <code>klass</code>, a superclass, or
7779 an implemented interface.
7780 </description>
7781 <origin>jvmdi</origin>
7782 <capabilities>
7783 </capabilities>
7784 <parameters>
7785 <param id="klass">
7786 <jclass field="field"/>
7787 <description>
7788 The class to query.
7789 </description>
7790 </param>
7791 <param id="field">
7792 <jfieldID class="klass"/>
7793 <description>
7794 The field to query.
7795 </description>
7796 </param>
7797 <param id="declaring_class_ptr">
7798 <outptr><jclass/></outptr>
7799 <description>
7800 On return, points to the declaring class
7801 </description>
7802 </param>
7803 </parameters>
7804 <errors>
7805 </errors>
7806 </function>
7807
7808 <function id="GetFieldModifiers" phase="start" num="62">
7809 <synopsis>Get Field Modifiers</synopsis>
7810 <description>
7811 For the field indicated by <code>klass</code> and <code>field</code>
7812 return the access flags via <code>modifiers_ptr</code>.
7813 Access flags are defined in <vmspec chapter="4"/>.
7814 </description>
7815 <origin>jvmdi</origin>
7816 <capabilities>
7817 </capabilities>
7818 <parameters>
7819 <param id="klass">
7820 <jclass field="field"/>
7821 <description>
7822 The class to query.
7823 </description>
7824 </param>
7825 <param id="field">
7826 <jfieldID class="klass"/>
7827 <description>
7828 The field to query.
7829 </description>
7830 </param>
7831 <param id="modifiers_ptr">
7832 <outptr><jint/></outptr>
7833 <description>
7834 On return, points to the access flags.
7835 </description>
7836 </param>
7837 </parameters>
7838 <errors>
7839 </errors>
7840 </function>
7841
7842 <function id="IsFieldSynthetic" phase="start" num="63">
7843 <synopsis>Is Field Synthetic</synopsis>
7844 <description>
7845 For the field indicated by <code>klass</code> and <code>field</code>, return a
7846 value indicating whether the field is synthetic via <code>is_synthetic_ptr</code>.
7847 Synthetic fields are generated by the compiler but not present in the
7848 original source code.
7849 </description>
7850 <origin>jvmdi</origin>
7851 <capabilities>
7852 <required id="can_get_synthetic_attribute"></required>
7853 </capabilities>
7854 <parameters>
7855 <param id="klass">
7856 <jclass field="field"/>
7857 <description>
7858 The class of the field to query.
7859 </description>
7860 </param>
7861 <param id="field">
7862 <jfieldID class="klass"/>
7863 <description>
7864 The field to query.
7865 </description>
7866 </param>
7867 <param id="is_synthetic_ptr">
7868 <outptr><jboolean/></outptr>
7869 <description>
7870 On return, points to the boolean result of this function.
7871 </description>
7872 </param>
7873 </parameters>
7874 <errors>
7875 </errors>
7876 </function>
7877
7878 </category>
7879
7880 <category id="method" label="Method">
7881
7882 <intro>
7883 These functions provide information about a method (represented as a
7884 <typelink id="jmethodID"/>) and set how methods are processed.
7885 </intro>
7886
7887 <intro id="obsoleteMethods" label="Obsolete Methods">
7888 The functions <functionlink id="RetransformClasses"/> and
7889 <functionlink id="RedefineClasses"/> can cause new versions
7890 of methods to be installed.
7891 An original version of a method is considered equivalent
7892 to the new version if:
7893 <ul>
7894 <li>their bytecodes are the same except for indices into the
7895 constant pool and </li>
7896 <li>the referenced constants are equal.</li>
7897 </ul>
7898 An original method version which is not equivalent to the
7899 new method version is called obsolete and is assigned a new method ID;
7900 the original method ID now refers to the new method version.
7901 A method ID can be tested for obsolescence with
7902 <functionlink id="IsMethodObsolete"/>.
7903 </intro>
7904
7905 <function id="GetMethodName" phase="start" num="64">
7906 <synopsis>Get Method Name (and Signature)</synopsis>
7907 <description>
7908 For the method indicated by <code>method</code>,
7909 return the method name via <code>name_ptr</code> and method signature via
7910 <code>signature_ptr</code>.
7911 <p/>
7912 Method signatures are defined in the JNI Specification and are
7913 referred to as <code>method descriptors</code> in
7914 <vmspec chapter="4.3.3"/>.
7915 Note this is different
7916 than method signatures as defined in the <i>Java Language Specification</i>.
7917 </description>
7918 <origin>jvmdiClone</origin>
7919 <capabilities>
7920 </capabilities>
7921 <parameters>
7922 <param id="method">
7923 <jmethodID/>
7924 <description>
7925 The method to query.
7926 </description>
7927 </param>
7928 <param id="name_ptr">
7929 <allocbuf>
7930 <char/>
7931 <nullok>the name is not returned</nullok>
7932 </allocbuf>
7933 <description>
7934 On return, points to the method name, encoded as a
7935 <internallink id="mUTF">modified UTF-8</internallink> string.
7936 </description>
7937 </param>
7938 <param id="signature_ptr">
7939 <allocbuf>
7940 <char/>
7941 <nullok>the signature is not returned</nullok>
7942 </allocbuf>
7943 <description>
7944 On return, points to the method signature, encoded as a
7945 <internallink id="mUTF">modified UTF-8</internallink> string.
7946 </description>
7947 </param>
7948 <param id="generic_ptr">
7949 <allocbuf>
7950 <char/>
7951 <nullok>the generic signature is not returned</nullok>
7952 </allocbuf>
7953 <description>
7954 On return, points to the generic signature of the method, encoded as a
7955 <internallink id="mUTF">modified UTF-8</internallink> string.
7956 If there is no generic signature attribute for the method, then,
7957 on return, points to <code>NULL</code>.
7958 </description>
7959 </param>
7960 </parameters>
7961 <errors>
7962 </errors>
7963 </function>
7964
7965 <function id="GetMethodDeclaringClass" phase="start" num="65">
7966 <synopsis>Get Method Declaring Class</synopsis>
7967 <description>
7968 For the method indicated by <code>method</code>,
7969 return the class that defined it via <code>declaring_class_ptr</code>.
7970 </description>
7971 <origin>jvmdi</origin>
7972 <capabilities>
7973 </capabilities>
7974 <parameters>
7975 <param id="klass">
7976 <jclass method="method"/>
7977 <description>
7978 The class to query.
7979 </description>
7980 </param>
7981 <param id="method">
7982 <jmethodID class="klass"/>
7983 <description>
7984 The method to query.
7985 </description>
7986 </param>
7987 <param id="declaring_class_ptr">
7988 <outptr><jclass/></outptr>
7989 <description>
7990 On return, points to the declaring class
7991 </description>
7992 </param>
7993 </parameters>
7994 <errors>
7995 </errors>
7996 </function>
7997
7998 <function id="GetMethodModifiers" phase="start" num="66">
7999 <synopsis>Get Method Modifiers</synopsis>
8000 <description>
8001 For the method indicated by <code>method</code>,
8002 return the access flags via <code>modifiers_ptr</code>.
8003 Access flags are defined in <vmspec chapter="4"/>.
8004 </description>
8005 <origin>jvmdi</origin>
8006 <capabilities>
8007 </capabilities>
8008 <parameters>
8009 <param id="klass">
8010 <jclass method="method"/>
8011 <description>
8012 The class to query.
8013 </description>
8014 </param>
8015 <param id="method">
8016 <jmethodID class="klass"/>
8017 <description>
8018 The method to query.
8019 </description>
8020 </param>
8021 <param id="modifiers_ptr">
8022 <outptr><jint/></outptr>
8023 <description>
8024 On return, points to the access flags.
8025 </description>
8026 </param>
8027 </parameters>
8028 <errors>
8029 </errors>
8030 </function>
8031
8032 <function id="GetMaxLocals" phase="start" num="68">
8033 <synopsis>Get Max Locals</synopsis>
8034 <description>
8035 For the method indicated by <code>method</code>,
8036 return the number of local variable slots used by the method,
8037 including the local variables used to pass parameters to the
8038 method on its invocation.
8039 <p/>
8040 See <code>max_locals</code> in <vmspec chapter="4.7.3"/>.
8041 </description>
8042 <origin>jvmdi</origin>
8043 <capabilities>
8044 </capabilities>
8045 <parameters>
8046 <param id="klass">
8047 <jclass method="method"/>
8048 <description>
8049 The class to query.
8050 </description>
8051 </param>
8052 <param id="method">
8053 <jmethodID class="klass" native="error"/>
8054 <description>
8055 The method to query.
8056 </description>
8057 </param>
8058 <param id="max_ptr">
8059 <outptr><jint/></outptr>
8060 <description>
8061 On return, points to the maximum number of local slots
8062 </description>
8063 </param>
8064 </parameters>
8065 <errors>
8066 </errors>
8067 </function>
8068
8069 <function id="GetArgumentsSize" phase="start" num="69">
8070 <synopsis>Get Arguments Size</synopsis>
8071 <description>
8072 For the method indicated by <code>method</code>,
8073 return via <code>max_ptr</code> the number of local variable slots used
8074 by the method's arguments.
8075 Note that two-word arguments use two slots.
8076 </description>
8077 <origin>jvmdi</origin>
8078 <capabilities>
8079 </capabilities>
8080 <parameters>
8081 <param id="klass">
8082 <jclass method="method"/>
8083 <description>
8084 The class to query.
8085 </description>
8086 </param>
8087 <param id="method">
8088 <jmethodID class="klass" native="error"/>
8089 <description>
8090 The method to query.
8091 </description>
8092 </param>
8093 <param id="size_ptr">
8094 <outptr><jint/></outptr>
8095 <description>
8096 On return, points to the number of argument slots
8097 </description>
8098 </param>
8099 </parameters>
8100 <errors>
8101 </errors>
8102 </function>
8103
8104 <function id="GetLineNumberTable" phase="start" num="70">
8105 <synopsis>Get Line Number Table</synopsis>
8106 <typedef id="jvmtiLineNumberEntry" label="Line number table entry">
8107 <field id="start_location">
8108 <jlocation/>
8109 <description>
8110 the <datalink id="jlocation"></datalink> where the line begins
8111 </description>
8112 </field>
8113 <field id="line_number">
8114 <jint/>
8115 <description>
8116 the line number
8117 </description>
8118 </field>
8119 </typedef>
8120 <description>
8121 For the method indicated by <code>method</code>,
8122 return a table of source line number entries. The size of the table is
8123 returned via <code>entry_count_ptr</code> and the table itself is
8124 returned via <code>table_ptr</code>.
8125 </description>
8126 <origin>jvmdi</origin>
8127 <capabilities>
8128 <required id="can_get_line_numbers"></required>
8129 </capabilities>
8130 <parameters>
8131 <param id="klass">
8132 <jclass method="method"/>
8133 <description>
8134 The class to query.
8135 </description>
8136 </param>
8137 <param id="method">
8138 <jmethodID class="klass" native="error"/>
8139 <description>
8140 The method to query.
8141 </description>
8142 </param>
8143 <param id="entry_count_ptr">
8144 <outptr><jint/></outptr>
8145 <description>
8146 On return, points to the number of entries in the table
8147 </description>
8148 </param>
8149 <param id="table_ptr">
8150 <allocbuf outcount="entry_count_ptr"><struct>jvmtiLineNumberEntry</struct></allocbuf>
8151 <description>
8152 On return, points to the line number table pointer.
8153 </description>
8154 </param>
8155 </parameters>
8156 <errors>
8157 <error id="JVMTI_ERROR_ABSENT_INFORMATION">
8158 Class information does not include line numbers.
8159 </error>
8160 </errors>
8161 </function>
8162
8163 <function id="GetMethodLocation" phase="start" num="71">
8164 <synopsis>Get Method Location</synopsis>
8165 <description>
8166 For the method indicated by <code>method</code>,
8167 return the beginning and ending addresses through
8168 <code>start_location_ptr</code> and <code>end_location_ptr</code>. In a
8169 conventional byte code indexing scheme,
8170 <code>start_location_ptr</code> will always point to zero
8171 and <code>end_location_ptr</code>
8172 will always point to the byte code count minus one.
8173 </description>
8174 <origin>jvmdi</origin>
8175 <capabilities>
8176 </capabilities>
8177 <parameters>
8178 <param id="klass">
8179 <jclass method="method"/>
8180 <description>
8181 The class to query.
8182 </description>
8183 </param>
8184 <param id="method">
8185 <jmethodID class="klass" native="error"/>
8186 <description>
8187 The method to query.
8188 </description>
8189 </param>
8190 <param id="start_location_ptr">
8191 <outptr><jlocation/></outptr>
8192 <description>
8193 On return, points to the first location, or
8194 <code>-1</code> if location information is not available.
8195 If the information is available and
8196 <functionlink id="GetJLocationFormat"></functionlink>
8197 returns <datalink id="JVMTI_JLOCATION_JVMBCI"></datalink>
8198 then this will always be zero.
8199 </description>
8200 </param>
8201 <param id="end_location_ptr">
8202 <outptr><jlocation/></outptr>
8203 <description>
8204 On return, points to the last location,
8205 or <code>-1</code> if location information is not available.
8206 </description>
8207 </param>
8208 </parameters>
8209 <errors>
8210 <error id="JVMTI_ERROR_ABSENT_INFORMATION">
8211 Class information does not include method sizes.
8212 </error>
8213 </errors>
8214 </function>
8215
8216 <function id="GetLocalVariableTable" num="72">
8217 <synopsis>Get Local Variable Table</synopsis>
8218 <typedef id="jvmtiLocalVariableEntry" label="Local variable table entry">
8219 <field id="start_location">
8220 <jlocation/>
8221 <description>
8222 The code array index where the local variable is first valid
8223 (that is, where it must have a value).
8224 </description>
8225 </field>
8226 <field id="length">
8227 <jint/>
8228 <description>
8229 The length of the valid section for this local variable.
8230 The last code array index where the local variable is valid
8231 is <code>start_location + length</code>.
8232 </description>
8233 </field>
8234 <field id="name">
8235 <allocfieldbuf><char/></allocfieldbuf>
8236 <description>
8237 The local variable name, encoded as a
8238 <internallink id="mUTF">modified UTF-8</internallink> string.
8239 </description>
8240 </field>
8241 <field id="signature">
8242 <allocfieldbuf><char/></allocfieldbuf>
8243 <description>
8244 The local variable's type signature, encoded as a
8245 <internallink id="mUTF">modified UTF-8</internallink> string.
8246 The signature format is the same as that defined in
8247 <vmspec chapter="4.3.2"/>.
8248 </description>
8249 </field>
8250 <field id="generic_signature">
8251 <allocfieldbuf><char/></allocfieldbuf>
8252 <description>
8253 The local variable's generic signature, encoded as a
8254 <internallink id="mUTF">modified UTF-8</internallink> string.
8255 The value of this field will be <code>NULL</code> for any local
8256 variable which does not have a generic type.
8257 </description>
8258 </field>
8259 <field id="slot">
8260 <jint/>
8261 <description>
8262 The local variable's slot. See <internallink id="local">Local Variables</internallink>.
8263 </description>
8264 </field>
8265 </typedef>
8266 <description>
8267 Return local variable information.
8268 </description>
8269 <origin>jvmdiClone</origin>
8270 <capabilities>
8271 <required id="can_access_local_variables"></required>
8272 </capabilities>
8273 <parameters>
8274 <param id="method">
8275 <jmethodID native="error"/>
8276 <description>
8277 The method to query.
8278 </description>
8279 </param>
8280 <param id="entry_count_ptr">
8281 <outptr><jint/></outptr>
8282 <description>
8283 On return, points to the number of entries in the table
8284 </description>
8285 </param>
8286 <param id="table_ptr">
8287 <allocbuf outcount="entry_count_ptr"><struct>jvmtiLocalVariableEntry</struct></allocbuf>
8288 <description>
8289 On return, points to an array of local variable table entries.
8290 </description>
8291 </param>
8292 </parameters>
8293 <errors>
8294 <error id="JVMTI_ERROR_ABSENT_INFORMATION">
8295 Class information does not include local variable
8296 information.
8297 </error>
8298 </errors>
8299 </function>
8300
8301 <function id="GetBytecodes" phase="start" num="75">
8302 <synopsis>Get Bytecodes</synopsis>
8303 <description>
8304 For the method indicated by <code>method</code>,
8305 return the byte codes that implement the method. The number of
8306 bytecodes is returned via <code>bytecode_count_ptr</code>. The byte codes
8307 themselves are returned via <code>bytecodes_ptr</code>.
8308 </description>
8309 <origin>jvmdi</origin>
8310 <capabilities>
8311 <required id="can_get_bytecodes"></required>
8312 </capabilities>
8313 <parameters>
8314 <param id="klass">
8315 <jclass method="method"/>
8316 <description>
8317 The class to query.
8318 </description>
8319 </param>
8320 <param id="method">
8321 <jmethodID class="klass" native="error"/>
8322 <description>
8323 The method to query.
8324 </description>
8325 </param>
8326 <param id="bytecode_count_ptr">
8327 <outptr><jint/></outptr>
8328 <description>
8329 On return, points to the length of the byte code array
8330 </description>
8331 </param>
8332 <param id="bytecodes_ptr">
8333 <allocbuf outcount="bytecode_count_ptr"><uchar/></allocbuf>
8334 <description>
8335 On return, points to the pointer to the byte code array
8336 </description>
8337 </param>
8338 </parameters>
8339 <errors>
8340 </errors>
8341 </function>
8342
8343 <function id="IsMethodNative" phase="start" num="76">
8344 <synopsis>Is Method Native</synopsis>
8345 <description>
8346 For the method indicated by <code>method</code>, return a
8347 value indicating whether the method is native via <code>is_native_ptr</code>
8348 </description>
8349 <origin>jvmdi</origin>
8350 <capabilities>
8351 </capabilities>
8352 <parameters>
8353 <param id="klass">
8354 <jclass method="method"/>
8355 <description>
8356 The class to query.
8357 </description>
8358 </param>
8359 <param id="method">
8360 <jmethodID class="klass"/>
8361 <description>
8362 The method to query.
8363 </description>
8364 </param>
8365 <param id="is_native_ptr">
8366 <outptr><jboolean/></outptr>
8367 <description>
8368 On return, points to the boolean result of this function.
8369 </description>
8370 </param>
8371 </parameters>
8372 <errors>
8373 </errors>
8374 </function>
8375
8376 <function id="IsMethodSynthetic" phase="start" num="77">
8377 <synopsis>Is Method Synthetic</synopsis>
8378 <description>
8379 For the method indicated by <code>method</code>, return a
8380 value indicating whether the method is synthetic via <code>is_synthetic_ptr</code>.
8381 Synthetic methods are generated by the compiler but not present in the
8382 original source code.
8383 </description>
8384 <origin>jvmdi</origin>
8385 <capabilities>
8386 <required id="can_get_synthetic_attribute"></required>
8387 </capabilities>
8388 <parameters>
8389 <param id="klass">
8390 <jclass method="method"/>
8391 <description>
8392 The class to query.
8393 </description>
8394 </param>
8395 <param id="method">
8396 <jmethodID class="klass"/>
8397 <description>
8398 The method to query.
8399 </description>
8400 </param>
8401 <param id="is_synthetic_ptr">
8402 <outptr><jboolean/></outptr>
8403 <description>
8404 On return, points to the boolean result of this function.
8405 </description>
8406 </param>
8407 </parameters>
8408 <errors>
8409 </errors>
8410 </function>
8411
8412 <function id="IsMethodObsolete" phase="start" num="91">
8413 <synopsis>Is Method Obsolete</synopsis>
8414 <description>
8415 Determine if a method ID refers to an
8416 <internallink id="obsoleteMethods">obsolete</internallink>
8417 method version.
8418 </description>
8419 <origin>jvmdi</origin>
8420 <capabilities>
8421 </capabilities>
8422 <parameters>
8423 <param id="klass">
8424 <jclass method="method"/>
8425 <description>
8426 The class to query.
8427 </description>
8428 </param>
8429 <param id="method">
8430 <jmethodID class="klass"/>
8431 <description>
8432 The method ID to query.
8433 </description>
8434 </param>
8435 <param id="is_obsolete_ptr">
8436 <outptr><jboolean/></outptr>
8437 <description>
8438 On return, points to the boolean result of this function.
8439 </description>
8440 </param>
8441 </parameters>
8442 <errors>
8443 </errors>
8444 </function>
8445
8446 <function id="SetNativeMethodPrefix" jkernel="yes" phase="any" num="73" since="1.1">
8447 <synopsis>Set Native Method Prefix</synopsis>
8448 <description>
8449 This function modifies the failure handling of
8450 native method resolution by allowing retry
8451 with a prefix applied to the name.
8452 When used with the
8453 <eventlink id="ClassFileLoadHook">ClassFileLoadHook
8454 event</eventlink>, it enables native methods to be
8455 <internallink id="bci">instrumented</internallink>.
8456 <p/>
8457 Since native methods cannot be directly instrumented
8458 (they have no bytecodes), they must be wrapped with
8459 a non-native method which can be instrumented.
8460 For example, if we had:
8461 <example>
8462 native boolean foo(int x);</example>
8463 <p/>
8464 We could transform the class file (with the
8465 ClassFileLoadHook event) so that this becomes:
8466 <example>
8467 boolean foo(int x) {
8468 <i>... record entry to foo ...</i>
8469 return wrapped_foo(x);
8470 }
8471
8472 native boolean wrapped_foo(int x);</example>
8473 <p/>
8474 Where foo becomes a wrapper for the actual native method
8475 with the appended prefix "wrapped_". Note that
8476 "wrapped_" would be a poor choice of prefix since it
8477 might conceivably form the name of an existing method
8478 thus something like "$$$MyAgentWrapped$$$_" would be
8479 better but would make these examples less readable.
8480 <p/>
8481 The wrapper will allow data to be collected on the native
8482 method call, but now the problem becomes linking up the
8483 wrapped method with the native implementation.
8484 That is, the method <code>wrapped_foo</code> needs to be
8485 resolved to the native implementation of <code>foo</code>,
8486 which might be:
8487 <example>
8488 Java_somePackage_someClass_foo(JNIEnv* env, jint x)</example>
8489 <p/>
8490 This function allows the prefix to be specified and the
8491 proper resolution to occur.
8492 Specifically, when the standard resolution fails, the
8493 resolution is retried taking the prefix into consideration.
8494 There are two ways that resolution occurs, explicit
8495 resolution with the JNI function <code>RegisterNatives</code>
8496 and the normal automatic resolution. For
8497 <code>RegisterNatives</code>, the VM will attempt this
8498 association:
8499 <example>
8500 method(foo) -> nativeImplementation(foo)</example>
8501 <p/>
8502 When this fails, the resolution will be retried with
8503 the specified prefix prepended to the method name,
8504 yielding the correct resolution:
8505 <example>
8506 method(wrapped_foo) -> nativeImplementation(foo)</example>
8507 <p/>
8508 For automatic resolution, the VM will attempt:
8509 <example>
8510 method(wrapped_foo) -> nativeImplementation(wrapped_foo)</example>
8511 <p/>
8512 When this fails, the resolution will be retried with
8513 the specified prefix deleted from the implementation name,
8514 yielding the correct resolution:
8515 <example>
8516 method(wrapped_foo) -> nativeImplementation(foo)</example>
8517 <p/>
8518 Note that since the prefix is only used when standard
8519 resolution fails, native methods can be wrapped selectively.
8520 <p/>
8521 Since each <jvmti/> environment is independent and
8522 can do its own transformation of the bytecodes, more
8523 than one layer of wrappers may be applied. Thus each
8524 environment needs its own prefix. Since transformations
8525 are applied in order, the prefixes, if applied, will
8526 be applied in the same order.
8527 The order of transformation application is described in
8528 the <eventlink id="ClassFileLoadHook"/> event.
8529 Thus if three environments applied
8530 wrappers, <code>foo</code> might become
8531 <code>$env3_$env2_$env1_foo</code>. But if, say,
8532 the second environment did not apply a wrapper to
8533 <code>foo</code> it would be just
8534 <code>$env3_$env1_foo</code>. To be able to
8535 efficiently determine the sequence of prefixes,
8536 an intermediate prefix is only applied if its non-native
8537 wrapper exists. Thus, in the last example, even though
8538 <code>$env1_foo</code> is not a native method, the
8539 <code>$env1_</code> prefix is applied since
8540 <code>$env1_foo</code> exists.
8541 <p/>
8542 Since the prefixes are used at resolution time
8543 and since resolution may be arbitrarily delayed, a
8544 native method prefix must remain set as long as there
8545 are corresponding prefixed native methods.
8546 </description>
8547 <origin>new</origin>
8548 <capabilities>
8549 <required id="can_set_native_method_prefix"></required>
8550 </capabilities>
8551 <parameters>
8552 <param id="prefix">
8553 <inbuf>
8554 <char/>
8555 <nullok>
8556 any existing prefix in this environment is cancelled
8557 </nullok>
8558 </inbuf>
8559 <description>
8560 The prefix to apply, encoded as a
8561 <internallink id="mUTF">modified UTF-8</internallink> string.
8562 </description>
8563 </param>
8564 </parameters>
8565 <errors>
8566 </errors>
8567 </function>
8568
8569 <function id="SetNativeMethodPrefixes" jkernel="yes" phase="any" num="74" since="1.1">
8570 <synopsis>Set Native Method Prefixes</synopsis>
8571 <description>
8572 For a normal agent, <functionlink id="SetNativeMethodPrefix"/>
8573 will provide all needed native method prefixing.
8574 For a meta-agent that performs multiple independent class
8575 file transformations (for example as a proxy for another
8576 layer of agents) this function allows each transformation
8577 to have its own prefix.
8578 The prefixes are applied in the order supplied and are
8579 processed in the same manor as described for the
8580 application of prefixes from multiple <jvmti/> environments
8581 in <functionlink id="SetNativeMethodPrefix"/>.
8582 <p/>
8583 Any previous prefixes are replaced. Thus, calling this
8584 function with a <paramlink id="prefix_count"/> of <code>0</code>
8585 disables prefixing in this environment.
8586 <p/>
8587 <functionlink id="SetNativeMethodPrefix"/> and this function
8588 are the two ways to set the prefixes.
8589 Calling <code>SetNativeMethodPrefix</code> with
8590 a prefix is the same as calling this function with
8591 <paramlink id="prefix_count"/> of <code>1</code>.
8592 Calling <code>SetNativeMethodPrefix</code> with
8593 <code>NULL</code> is the same as calling this function with
8594 <paramlink id="prefix_count"/> of <code>0</code>.
8595 </description>
8596 <origin>new</origin>
8597 <capabilities>
8598 <required id="can_set_native_method_prefix"></required>
8599 </capabilities>
8600 <parameters>
8601 <param id="prefix_count">
8602 <jint min="0"/>
8603 <description>
8604 The number of prefixes to apply.
8605 </description>
8606 </param>
8607 <param id="prefixes">
8608 <agentbuf>
8609 <char/>
8610 </agentbuf>
8611 <description>
8612 The prefixes to apply for this environment, each encoded as a
8613 <internallink id="mUTF">modified UTF-8</internallink> string.
8614 </description>
8615 </param>
8616 </parameters>
8617 <errors>
8618 </errors>
8619 </function>
8620
8621 </category>
8622
8623 <category id="RawMonitors" label="Raw Monitor">
8624
8625 <function id="CreateRawMonitor" phase="onload" callbacksafe="safe" num="31">
8626 <synopsis>Create Raw Monitor</synopsis>
8627 <description>
8628 Create a raw monitor.
8629 </description>
8630 <origin>jvmdi</origin>
8631 <capabilities>
8632 </capabilities>
8633 <parameters>
8634 <param id="name">
8635 <inbuf><char/></inbuf>
8636 <description>
8637 A name to identify the monitor, encoded as a
8638 <internallink id="mUTF">modified UTF-8</internallink> string.
8639 </description>
8640 </param>
8641 <param id="monitor_ptr">
8642 <outptr><jrawMonitorID/></outptr>
8643 <description>
8644 On return, points to the created monitor.
8645 </description>
8646 </param>
8647 </parameters>
8648 <errors>
8649 </errors>
8650 </function>
8651
8652 <function id="DestroyRawMonitor" phase="onload" callbacksafe="safe" num="32">
8653 <synopsis>Destroy Raw Monitor</synopsis>
8654 <description>
8655 Destroy the raw monitor.
8656 If the monitor being destroyed has been entered by this thread, it will be
8657 exited before it is destroyed.
8658 If the monitor being destroyed has been entered by another thread,
8659 an error will be returned and the monitor will not be destroyed.
8660 </description>
8661 <origin>jvmdi</origin>
8662 <capabilities>
8663 </capabilities>
8664 <parameters>
8665 <param id="monitor">
8666 <jrawMonitorID/>
8667 <description>
8668 The monitor
8669 </description>
8670 </param>
8671 </parameters>
8672 <errors>
8673 <error id="JVMTI_ERROR_NOT_MONITOR_OWNER">
8674 Not monitor owner
8675 </error>
8676 </errors>
8677 </function>
8678
8679 <function id="RawMonitorEnter" phase="any" callbacksafe="safe" impl="innative notrace" num="33">
8680 <synopsis>Raw Monitor Enter</synopsis>
8681 <description>
8682 Gain exclusive ownership of a raw monitor.
8683 The same thread may enter a monitor more then once.
8684 The thread must
8685 <functionlink id="RawMonitorExit">exit</functionlink>
8686 the monitor the same number of times as it is entered.
8687 If a monitor is entered during <code>OnLoad</code> (before attached threads exist)
8688 and has not exited when attached threads come into existence, the enter
8689 is considered to have occurred on the main thread.
8690 </description>
8691 <origin>jvmdi</origin>
8692 <capabilities>
8693 </capabilities>
8694 <parameters>
8695 <param id="monitor">
8696 <jrawMonitorID/>
8697 <description>
8698 The monitor
8699 </description>
8700 </param>
8701 </parameters>
8702 <errors>
8703 </errors>
8704 </function>
8705
8706 <function id="RawMonitorExit" phase="any" callbacksafe="safe" impl="innative notrace" num="34">
8707 <synopsis>Raw Monitor Exit</synopsis>
8708 <description>
8709 Release exclusive ownership of a raw monitor.
8710 </description>
8711 <origin>jvmdi</origin>
8712 <capabilities>
8713 </capabilities>
8714 <parameters>
8715 <param id="monitor">
8716 <jrawMonitorID/>
8717 <description>
8718 The monitor
8719 </description>
8720 </param>
8721 </parameters>
8722 <errors>
8723 <error id="JVMTI_ERROR_NOT_MONITOR_OWNER">
8724 Not monitor owner
8725 </error>
8726 </errors>
8727 </function>
8728
8729 <function id="RawMonitorWait" phase="any" callbacksafe="safe" impl="innative notrace" num="35">
8730 <synopsis>Raw Monitor Wait</synopsis>
8731 <description>
8732 Wait for notification of the raw monitor.
8733 <p/>
8734 Causes the current thread to wait until either another thread calls
8735 <functionlink id="RawMonitorNotify"/> or
8736 <functionlink id="RawMonitorNotifyAll"/>
8737 for the specified raw monitor, or the specified
8738 <paramlink id="millis">timeout</paramlink>
8739 has elapsed.
8740 </description>
8741 <origin>jvmdi</origin>
8742 <capabilities>
8743 </capabilities>
8744 <parameters>
8745 <param id="monitor">
8746 <jrawMonitorID/>
8747 <description>
8748 The monitor
8749 </description>
8750 </param>
8751 <param id="millis">
8752 <jlong/>
8753 <description>
8754 The timeout, in milliseconds. If the timeout is
8755 zero, then real time is not taken into consideration
8756 and the thread simply waits until notified.
8757 </description>
8758 </param>
8759 </parameters>
8760 <errors>
8761 <error id="JVMTI_ERROR_NOT_MONITOR_OWNER">
8762 Not monitor owner
8763 </error>
8764 <error id="JVMTI_ERROR_INTERRUPT">
8765 Wait was interrupted, try again
8766 </error>
8767 </errors>
8768 </function>
8769
8770 <function id="RawMonitorNotify" phase="any" callbacksafe="safe" impl="notrace" num="36">
8771 <synopsis>Raw Monitor Notify</synopsis>
8772 <description>
8773 Notify a single thread waiting on the raw monitor.
8774 </description>
8775 <origin>jvmdi</origin>
8776 <capabilities>
8777 </capabilities>
8778 <parameters>
8779 <param id="monitor">
8780 <jrawMonitorID/>
8781 <description>
8782 The monitor
8783 </description>
8784 </param>
8785 </parameters>
8786 <errors>
8787 <error id="JVMTI_ERROR_NOT_MONITOR_OWNER">
8788 Not monitor owner
8789 </error>
8790 </errors>
8791 </function>
8792
8793 <function id="RawMonitorNotifyAll" phase="any" callbacksafe="safe" impl="notrace" num="37">
8794 <synopsis>Raw Monitor Notify All</synopsis>
8795 <description>
8796 Notify all threads waiting on the raw monitor.
8797 </description>
8798 <origin>jvmdi</origin>
8799 <capabilities>
8800 </capabilities>
8801 <parameters>
8802 <param id="monitor">
8803 <jrawMonitorID/>
8804 <description>
8805 The monitor
8806 </description>
8807 </param>
8808 </parameters>
8809 <errors>
8810 <error id="JVMTI_ERROR_NOT_MONITOR_OWNER">
8811 Not monitor owner
8812 </error>
8813 </errors>
8814 </function>
8815
8816 <elide>
8817 <function id="GetRawMonitorUse" num="118">
8818 <synopsis>Get Raw Monitor Use</synopsis>
8819 <description>
8820 The fields of the <functionlink id="jvmtiMonitorUsage"></functionlink> structure
8821 are filled in with information about usage of the raw monitor.
8822 </description>
8823 <origin>new</origin>
8824 <capabilities>
8825 <required id="can_get_raw_monitor_usage"></required>
8826 </capabilities>
8827 <parameters>
8828 <param id="monitor">
8829 <jrawMonitorID/>
8830 <description>
8831 the raw monitor to query.
8832 </description>
8833 </param>
8834 <param id="info_ptr">
8835 <outptr><struct>jvmtiMonitorUsage</struct></outptr>
8836 <description>
8837 On return, filled with monitor information for the
8838 specified raw monitor.
8839 </description>
8840 </param>
8841 </parameters>
8842 <errors>
8843 </errors>
8844 </function>
8845
8846 <function id="GetRawMonitors" num="119">
8847 <synopsis>Get Raw Monitors</synopsis>
8848 <description>
8849 Return the list of raw monitors.
8850 <p/>
8851 Note: details about each monitor can be examined with
8852 <functionlink id="GetRawMonitorUse"></functionlink>.
8853 </description>
8854 <origin>new</origin>
8855 <capabilities>
8856 <required id="can_get_raw_monitor_usage"></required>
8857 </capabilities>
8858 <parameters>
8859 <param id="monitorCnt">
8860 <outptr><jint/></outptr>
8861 <description>
8862 On return, pointer to the number
8863 of monitors returned in <code>monitors_ptr</code>.
8864 </description>
8865 </param>
8866 <param id="monitors_ptr">
8867 <allocbuf outcount="monitorCnt"><jrawMonitorID/></allocbuf>
8868 <description>
8869 On return, pointer to the monitor list.
8870 </description>
8871 </param>
8872 </parameters>
8873 <errors>
8874 </errors>
8875 </function>
8876 </elide>
8877 </category>
8878
8879 <category id="jniIntercept" label="JNI Function Interception">
8880
8881 <intro>
8882 Provides the ability to intercept and resend
8883 Java Native Interface (JNI) function calls
8884 by manipulating the JNI function table.
8885 See <externallink id="http://docs.oracle.com/javase/7/docs/technotes/guides/jni/spec/functions.html">JNI
8886 Functions</externallink> in the <i>Java Native Interface Specification</i>.
8887 <p/>
8888 The following example illustrates intercepting the
8889 <code>NewGlobalRef</code> JNI call in order to count reference
8890 creation.
8891 <example>
8892 JNIEnv original_jni_Functions;
8893 JNIEnv redirected_jni_Functions;
8894 int my_global_ref_count = 0;
8895
8896 jobject
8897 MyNewGlobalRef(JNIEnv *jni_env, jobject lobj) {
8898 ++my_global_ref_count;
8899 return originalJNIFunctions->NewGlobalRef(env, lobj);
8900 }
8901
8902 void
8903 myInit() {
8904 jvmtiError err;
8905
8906 err = (*jvmti_env)->GetJNIFunctionTable(jvmti_env, &original_jni_Functions);
8907 if (err != JVMTI_ERROR_NONE) {
8908 die();
8909 }
8910 err = (*jvmti_env)->GetJNIFunctionTable(jvmti_env, &redirected_jni_Functions);
8911 if (err != JVMTI_ERROR_NONE) {
8912 die();
8913 }
8914 redirectedJNIFunctions->NewGlobalRef = MyNewGlobalRef;
8915 err = (*jvmti_env)->SetJNIFunctionTable(jvmti_env, redirected_jni_Functions);
8916 if (err != JVMTI_ERROR_NONE) {
8917 die();
8918 }
8919 }
8920 </example>
8921 Sometime after <code>myInit</code> is called the user's JNI
8922 code is executed which makes the call to create a new global
8923 reference. Instead of going to the normal JNI implementation
8924 the call goes to <code>myNewGlobalRef</code>. Note that a
8925 copy of the original function table is kept so that the normal
8926 JNI function can be called after the data is collected.
8927 Note also that any JNI functions which are not overwritten
8928 will behave normally.
8929 <todo>
8930 check that the example compiles and executes.
8931 </todo>
8932 </intro>
8933
8934 <function id="SetJNIFunctionTable" phase="start" num="120">
8935 <synopsis>Set JNI Function Table</synopsis>
8936 <description>
8937 Set the JNI function table
8938 in all current and future JNI environments.
8939 As a result, all future JNI calls are directed to the specified functions.
8940 Use <functionlink id="GetJNIFunctionTable"></functionlink> to get the
8941 function table to pass to this function.
8942 For this function to take effect the the updated table entries must be
8943 used by the JNI clients.
8944 Since the table is defined <code>const</code> some compilers may optimize
8945 away the access to the table, thus preventing this function from taking
8946 effect.
8947 The table is copied--changes to the local copy of the
8948 table have no effect.
8949 This function affects only the function table, all other aspects of the environment are
8950 unaffected.
8951 See the examples <internallink id="jniIntercept">above</internallink>.
8952 </description>
8953 <origin>new</origin>
8954 <capabilities>
8955 </capabilities>
8956 <parameters>
8957 <param id="function_table">
8958 <inptr>
8959 <struct>jniNativeInterface</struct>
8960 </inptr>
8961 <description>
8962 Points to the new JNI function table.
8963 </description>
8964 </param>
8965 </parameters>
8966 <errors>
8967 </errors>
8968 </function>
8969
8970 <function id="GetJNIFunctionTable" phase="start" num="121">
8971 <synopsis>Get JNI Function Table</synopsis>
8972 <description>
8973 Get the JNI function table.
8974 The JNI function table is copied into allocated memory.
8975 If <functionlink id="SetJNIFunctionTable"></functionlink>
8976 has been called, the modified (not the original) function
8977 table is returned.
8978 Only the function table is copied, no other aspects of the environment
8979 are copied.
8980 See the examples <internallink id="jniIntercept">above</internallink>.
8981 </description>
8982 <origin>new</origin>
8983 <capabilities>
8984 </capabilities>
8985 <parameters>
8986 <param id="function_table">
8987 <allocbuf>
8988 <struct>jniNativeInterface</struct>
8989 </allocbuf>
8990 <description>
8991 On return, <code>*function_table</code>
8992 points a newly allocated copy of the JNI function table.
8993 </description>
8994 </param>
8995 </parameters>
8996 <errors>
8997 </errors>
8998 </function>
8999
9000 </category>
9001
9002 <category id="eventManagement" label="Event Management">
9003
9004 <function id="SetEventCallbacks" jkernel="yes" phase="onload" num="122">
9005 <synopsis>Set Event Callbacks</synopsis>
9006 <description>
9007 Set the functions to be called for each event.
9008 The callbacks are specified by supplying a replacement function table.
9009 The function table is copied--changes to the local copy of the
9010 table have no effect.
9011 This is an atomic action, all callbacks are set at once.
9012 No events are sent before this function is called.
9013 When an entry is <code>NULL</code> or when the event is beyond
9014 <paramlink id="size_of_callbacks"></paramlink> no event is sent.
9015 Details on events are
9016 described <internallink id="EventSection">later</internallink> in this document.
9017 An event must be enabled and have a callback in order to be
9018 sent--the order in which this function and
9019 <functionlink id="SetEventNotificationMode"></functionlink>
9020 are called does not affect the result.
9021 </description>
9022 <origin>new</origin>
9023 <capabilities>
9024 </capabilities>
9025 <parameters>
9026 <param id="callbacks">
9027 <inptr>
9028 <struct>jvmtiEventCallbacks</struct>
9029 <nullok>remove the existing callbacks</nullok>
9030 </inptr>
9031 <description>
9032 The new event callbacks.
9033 </description>
9034 </param>
9035 <param id="size_of_callbacks">
9036 <jint min="0"/>
9037 <description>
9038 <code>sizeof(jvmtiEventCallbacks)</code>--for version
9039 compatibility.
9040 </description>
9041 </param>
9042 </parameters>
9043 <errors>
9044 </errors>
9045 </function>
9046
9047 <function id="SetEventNotificationMode" jkernel="yes" phase="onload" num="2">
9048 <synopsis>Set Event Notification Mode</synopsis>
9049 <description>
9050 Control the generation of events.
9051 <constants id="jvmtiEventMode" label="Event Enable/Disable" kind="enum">
9052 <constant id="JVMTI_ENABLE" num="1">
9053 If <paramlink id="mode"></paramlink> is <code>JVMTI_ENABLE</code>,
9054 the event <paramlink id="event_type"></paramlink> will be enabled
9055 </constant>
9056 <constant id="JVMTI_DISABLE" num="0">
9057 If <paramlink id="mode"></paramlink> is <code>JVMTI_DISABLE</code>,
9058 the event <paramlink id="event_type"></paramlink> will be disabled
9059 </constant>
9060 </constants>
9061 If <code>thread</code> is <code>NULL</code>,
9062 the event is enabled or disabled globally; otherwise, it is
9063 enabled or disabled for a particular thread.
9064 An event is generated for
9065 a particular thread if it is enabled either at the thread or global
9066 levels.
9067 <p/>
9068 See <internallink id="EventIndex">below</internallink> for information on specific events.
9069 <p/>
9070 The following events cannot be controlled at the thread
9071 level through this function.
9072 <ul>
9073 <li><eventlink id="VMInit"></eventlink></li>
9074 <li><eventlink id="VMStart"></eventlink></li>
9075 <li><eventlink id="VMDeath"></eventlink></li>
9076 <li><eventlink id="ThreadStart"></eventlink></li>
9077 <li><eventlink id="CompiledMethodLoad"></eventlink></li>
9078 <li><eventlink id="CompiledMethodUnload"></eventlink></li>
9079 <li><eventlink id="DynamicCodeGenerated"></eventlink></li>
9080 <li><eventlink id="DataDumpRequest"></eventlink></li>
9081 </ul>
9082 <p/>
9083 Initially, no events are enabled at either the thread level
9084 or the global level.
9085 <p/>
9086 Any needed capabilities (see Event Enabling Capabilities below) must be possessed
9087 before calling this function.
9088 <p/>
9089 Details on events are
9090 described <internallink id="EventSection">below</internallink>.
9091 </description>
9092 <origin>jvmdiClone</origin>
9093 <eventcapabilities></eventcapabilities>
9094 <parameters>
9095 <param id="mode">
9096 <enum>jvmtiEventMode</enum>
9097 <description>
9098 <code>JVMTI_ENABLE</code> or <code>JVMTI_DISABLE</code>
9099 </description>
9100 </param>
9101 <param id="event_type">
9102 <enum>jvmtiEvent</enum>
9103 <description>
9104 the event to control
9105 </description>
9106 </param>
9107 <param id="event_thread">
9108 <ptrtype>
9109 <jthread impl="noconvert"/>
9110 <nullok>event is controlled at the global level</nullok>
9111 </ptrtype>
9112 <description>
9113 The thread to control
9114 </description>
9115 </param>
9116 <param id="...">
9117 <varargs/>
9118 <description>
9119 for future expansion
9120 </description>
9121 </param>
9122 </parameters>
9123 <errors>
9124 <error id="JVMTI_ERROR_INVALID_THREAD">
9125 <paramlink id="event_thread"/> is non-<code>NULL</code> and is not a valid thread.
9126 </error>
9127 <error id="JVMTI_ERROR_THREAD_NOT_ALIVE">
9128 <paramlink id="event_thread"/> is non-<code>NULL</code> and is not live (has not been started or is now dead).
9129 </error>
9130 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
9131 thread level control was attempted on events which do not
9132 permit thread level control.
9133 </error>
9134 <error id="JVMTI_ERROR_MUST_POSSESS_CAPABILITY">
9135 The Required Event Enabling Capability is not possessed.
9136 </error>
9137 </errors>
9138 </function>
9139
9140 <function id="GenerateEvents" num="123">
9141 <synopsis>Generate Events</synopsis>
9142 <description>
9143 Generate events to represent the current state of the VM.
9144 For example, if <paramlink id="event_type"/> is
9145 <code>JVMTI_EVENT_COMPILED_METHOD_LOAD</code>,
9146 a <eventlink id="CompiledMethodLoad"></eventlink> event will be
9147 sent for each currently compiled method.
9148 Methods that were loaded and now have been unloaded are not sent.
9149 The history of what events have previously been sent does not
9150 effect what events are sent by this function--for example,
9151 all currently compiled methods
9152 will be sent each time this function is called.
9153 <p/>
9154 This function is useful when
9155 events may have been missed due to the agent attaching after program
9156 execution begins; this function generates the missed events.
9157 <p/>
9158 Attempts to execute Java programming language code or
9159 JNI functions may be paused until this function returns -
9160 so neither should be called from the thread sending the event.
9161 This function returns only after the missed events have been
9162 sent, processed and have returned.
9163 The event may be sent on a different thread than the thread
9164 on which the event occurred.
9165 The callback for the event must be set with
9166 <functionlink id="SetEventCallbacks"></functionlink>
9167 and the event must be enabled with
9168 <functionlink id="SetEventNotificationMode"></functionlink>
9169 or the events will not occur.
9170 If the VM no longer has the information to generate some or
9171 all of the requested events, the events are simply not sent -
9172 no error is returned.
9173 <p/>
9174 Only the following events are supported:
9175 <ul>
9176 <li><eventlink id="CompiledMethodLoad"></eventlink></li>
9177 <li><eventlink id="DynamicCodeGenerated"></eventlink></li>
9178 </ul>
9179 </description>
9180 <origin>new</origin>
9181 <capabilities>
9182 <capability id="can_generate_compiled_method_load_events"></capability>
9183 </capabilities>
9184 <parameters>
9185 <param id="event_type">
9186 <enum>jvmtiEvent</enum>
9187 <description>
9188 The type of event to generate. Must be one of these:
9189 <ul>
9190 <li><eventlink id="CompiledMethodLoad"><code>JVMTI_EVENT_COMPILED_METHOD_LOAD</code></eventlink></li>
9191 <li><eventlink id="DynamicCodeGenerated"><code>JVMTI_EVENT_DYNAMIC_CODE_GENERATED</code></eventlink></li>
9192 </ul>
9193 </description>
9194 </param>
9195 </parameters>
9196 <errors>
9197 <error id="JVMTI_ERROR_MUST_POSSESS_CAPABILITY">
9198 <paramlink id="event_type"/> is
9199 <eventlink id="CompiledMethodLoad"><code>JVMTI_EVENT_COMPILED_METHOD_LOAD</code></eventlink>
9200 and <fieldlink id="can_generate_compiled_method_load_events" struct="jvmtiCapabilities"></fieldlink>
9201 is <code>false</code>.
9202 </error>
9203 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
9204 <paramlink id="event_type"/> is other than
9205 <eventlink id="CompiledMethodLoad"><code>JVMTI_EVENT_COMPILED_METHOD_LOAD</code></eventlink>
9206 or <eventlink id="DynamicCodeGenerated"><code>JVMTI_EVENT_DYNAMIC_CODE_GENERATED</code></eventlink>.
9207 </error>
9208 </errors>
9209 </function>
9210
9211 </category>
9212
9213 <category id="extension" label="Extension Mechanism">
9214
9215 <intro>
9216 These functions
9217 allow a <jvmti/> implementation to provide functions and events
9218 beyond those defined in this specification.
9219 <p/>
9220 Both extension functions and extension events have parameters
9221 each of which has a 'type' and 'kind' chosen from the following tables:
9222
9223 <constants id="jvmtiParamTypes" label="Extension Function/Event Parameter Types" kind="enum">
9224 <constant id="JVMTI_TYPE_JBYTE" num="101">
9225 Java programming language primitive type - <code>byte</code>.
9226 JNI type <code>jbyte</code>.
9227 </constant>
9228 <constant id="JVMTI_TYPE_JCHAR" num="102">
9229 Java programming language primitive type - <code>char</code>.
9230 JNI type <code>jchar</code>.
9231 </constant>
9232 <constant id="JVMTI_TYPE_JSHORT" num="103">
9233 Java programming language primitive type - <code>short</code>.
9234 JNI type <code>jshort</code>.
9235 </constant>
9236 <constant id="JVMTI_TYPE_JINT" num="104">
9237 Java programming language primitive type - <code>int</code>.
9238 JNI type <datalink id="jint"></datalink>.
9239 </constant>
9240 <constant id="JVMTI_TYPE_JLONG" num="105">
9241 Java programming language primitive type - <code>long</code>.
9242 JNI type <datalink id="jlong"></datalink>.
9243 </constant>
9244 <constant id="JVMTI_TYPE_JFLOAT" num="106">
9245 Java programming language primitive type - <code>float</code>.
9246 JNI type <datalink id="jfloat"></datalink>.
9247 </constant>
9248 <constant id="JVMTI_TYPE_JDOUBLE" num="107">
9249 Java programming language primitive type - <code>double</code>.
9250 JNI type <datalink id="jdouble"></datalink>.
9251 </constant>
9252 <constant id="JVMTI_TYPE_JBOOLEAN" num="108">
9253 Java programming language primitive type - <code>boolean</code>.
9254 JNI type <datalink id="jboolean"></datalink>.
9255 </constant>
9256 <constant id="JVMTI_TYPE_JOBJECT" num="109">
9257 Java programming language object type - <code>java.lang.Object</code>.
9258 JNI type <datalink id="jobject"></datalink>.
9259 Returned values are JNI local references and must be managed.
9260 </constant>
9261 <constant id="JVMTI_TYPE_JTHREAD" num="110">
9262 Java programming language object type - <code>java.lang.Thread</code>.
9263 <jvmti/> type <datalink id="jthread"></datalink>.
9264 Returned values are JNI local references and must be managed.
9265 </constant>
9266 <constant id="JVMTI_TYPE_JCLASS" num="111">
9267 Java programming language object type - <code>java.lang.Class</code>.
9268 JNI type <datalink id="jclass"></datalink>.
9269 Returned values are JNI local references and must be managed.
9270 </constant>
9271 <constant id="JVMTI_TYPE_JVALUE" num="112">
9272 Union of all Java programming language primitive and object types -
9273 JNI type <datalink id="jvalue"></datalink>.
9274 Returned values which represent object types are JNI local references and must be managed.
9275 </constant>
9276 <constant id="JVMTI_TYPE_JFIELDID" num="113">
9277 Java programming language field identifier -
9278 JNI type <datalink id="jfieldID"></datalink>.
9279 </constant>
9280 <constant id="JVMTI_TYPE_JMETHODID" num="114">
9281 Java programming language method identifier -
9282 JNI type <datalink id="jmethodID"></datalink>.
9283 </constant>
9284 <constant id="JVMTI_TYPE_CCHAR" num="115">
9285 C programming language type - <code>char</code>.
9286 </constant>
9287 <constant id="JVMTI_TYPE_CVOID" num="116">
9288 C programming language type - <code>void</code>.
9289 </constant>
9290 <constant id="JVMTI_TYPE_JNIENV" num="117">
9291 JNI environment - <code>JNIEnv</code>.
9292 Should be used with the correct <datalink id="jvmtiParamKind"/> to make it a pointer type.
9293 </constant>
9294 </constants>
9295
9296 <constants id="jvmtiParamKind" label="Extension Function/Event Parameter Kinds" kind="enum">
9297 <constant id="JVMTI_KIND_IN" num="91">
9298 Ingoing argument - <code>foo</code>.
9299 </constant>
9300 <constant id="JVMTI_KIND_IN_PTR" num="92">
9301 Ingoing pointer argument - <code>const foo*</code>.
9302 </constant>
9303 <constant id="JVMTI_KIND_IN_BUF" num="93">
9304 Ingoing array argument - <code>const foo*</code>.
9305 </constant>
9306 <constant id="JVMTI_KIND_ALLOC_BUF" num="94">
9307 Outgoing allocated array argument - <code>foo**</code>.
9308 Free with <code>Deallocate</code>.
9309 </constant>
9310 <constant id="JVMTI_KIND_ALLOC_ALLOC_BUF" num="95">
9311 Outgoing allocated array of allocated arrays argument - <code>foo***</code>.
9312 Free with <code>Deallocate</code>.
9313 </constant>
9314 <constant id="JVMTI_KIND_OUT" num="96">
9315 Outgoing argument - <code>foo*</code>.
9316 </constant>
9317 <constant id="JVMTI_KIND_OUT_BUF" num="97">
9318 Outgoing array argument (pre-allocated by agent) - <code>foo*</code>.
9319 Do not <code>Deallocate</code>.
9320 </constant>
9321 </constants>
9322
9323 </intro>
9324
9325 <typedef id="jvmtiParamInfo" label="Extension Function/Event Parameter Info">
9326 <field id="name">
9327 <allocfieldbuf><char/></allocfieldbuf>
9328 <description>
9329 The parameter name, encoded as a
9330 <internallink id="mUTF">modified UTF-8</internallink> string
9331 </description>
9332 </field>
9333 <field id="kind">
9334 <enum>jvmtiParamKind</enum>
9335 <description>
9336 The kind of the parameter - type modifiers
9337 </description>
9338 </field>
9339 <field id="base_type">
9340 <enum>jvmtiParamTypes</enum>
9341 <description>
9342 The base type of the parameter - modified by <code>kind</code>
9343 </description>
9344 </field>
9345 <field id="null_ok">
9346 <jboolean/>
9347 <description>
9348 Is a <code>NULL</code> argument permitted? Applies only to pointer and object types.
9349 </description>
9350 </field>
9351 </typedef>
9352
9353 <callback id="jvmtiExtensionFunction">
9354 <enum>jvmtiError</enum>
9355 <synopsis>Extension Function</synopsis>
9356 <description>
9357 This is the implementation-specific extension function.
9358 </description>
9359 <parameters>
9360 <param id="jvmti_env">
9361 <outptr>
9362 <struct>jvmtiEnv</struct>
9363 </outptr>
9364 <description>
9365 The <jvmti/> environment is the only fixed parameter for extension functions.
9366 </description>
9367 </param>
9368 <param id="...">
9369 <varargs/>
9370 <description>
9371 The extension function-specific parameters
9372 </description>
9373 </param>
9374 </parameters>
9375 </callback>
9376
9377 <function id="GetExtensionFunctions" phase="onload" num="124">
9378 <synopsis>Get Extension Functions</synopsis>
9379
9380 <typedef id="jvmtiExtensionFunctionInfo" label="Extension Function Info">
9381 <field id="func">
9382 <ptrtype>
9383 <struct>jvmtiExtensionFunction</struct>
9384 </ptrtype>
9385 <description>
9386 The actual function to call
9387 </description>
9388 </field>
9389 <field id="id">
9390 <allocfieldbuf><char/></allocfieldbuf>
9391 <description>
9392 The identifier for the extension function, encoded as a
9393 <internallink id="mUTF">modified UTF-8</internallink> string.
9394 Uses package name conventions.
9395 For example, <code>com.sun.hotspot.bar</code>
9396 </description>
9397 </field>
9398 <field id="short_description">
9399 <allocfieldbuf><char/></allocfieldbuf>
9400 <description>
9401 A one sentence description of the function, encoded as a
9402 <internallink id="mUTF">modified UTF-8</internallink> string.
9403 </description>
9404 </field>
9405 <field id="param_count">
9406 <jint/>
9407 <description>
9408 The number of parameters excluding <code>jvmtiEnv *jvmti_env</code>
9409 </description>
9410 </field>
9411 <field id="params">
9412 <allocfieldbuf outcount="param_count">
9413 <struct>jvmtiParamInfo</struct>
9414 </allocfieldbuf>
9415 <description>
9416 Array of
9417 <fieldlink id="param_count" struct="jvmtiExtensionFunctionInfo"></fieldlink>
9418 parameters (<code>jvmtiEnv *jvmti_env</code> excluded)
9419 </description>
9420 </field>
9421 <field id="error_count">
9422 <jint/>
9423 <description>
9424 The number of possible error returns (excluding universal errors)
9425 </description>
9426 </field>
9427 <field id="errors">
9428 <allocfieldbuf outcount="error_count">
9429 <enum>jvmtiError</enum>
9430 </allocfieldbuf>
9431 <description>
9432 Array of <fieldlink id="error_count" struct="jvmtiExtensionFunctionInfo"></fieldlink>
9433 possible errors
9434 </description>
9435 </field>
9436 </typedef>
9437
9438 <description>
9439 Returns the set of extension functions.
9440 </description>
9441 <origin>new</origin>
9442 <capabilities>
9443 </capabilities>
9444 <parameters>
9445 <param id="extension_count_ptr">
9446 <outptr><jint/></outptr>
9447 <description>
9448 On return, points to the number of extension functions
9449 </description>
9450 </param>
9451 <param id="extensions">
9452 <allocbuf outcount="extension_count_ptr"><struct>jvmtiExtensionFunctionInfo</struct></allocbuf>
9453 <description>
9454 Returns an array of extension function info, one per function
9455 </description>
9456 </param>
9457 </parameters>
9458 <errors>
9459 </errors>
9460 </function>
9461
9462 <function id="GetExtensionEvents" phase="onload" num="125">
9463 <synopsis>Get Extension Events</synopsis>
9464
9465 <typedef id="jvmtiExtensionEventInfo" label="Extension Event Info">
9466 <field id="extension_event_index">
9467 <jint/>
9468 <description>
9469 The identifying index of the event
9470 </description>
9471 </field>
9472 <field id="id">
9473 <allocfieldbuf><char/></allocfieldbuf>
9474 <description>
9475 The identifier for the extension event, encoded as a
9476 <internallink id="mUTF">modified UTF-8</internallink> string.
9477 Uses package name conventions.
9478 For example, <code>com.sun.hotspot.bar</code>
9479 </description>
9480 </field>
9481 <field id="short_description">
9482 <allocfieldbuf><char/></allocfieldbuf>
9483 <description>
9484 A one sentence description of the event, encoded as a
9485 <internallink id="mUTF">modified UTF-8</internallink> string.
9486 </description>
9487 </field>
9488 <field id="param_count">
9489 <jint/>
9490 <description>
9491 The number of parameters excluding <code>jvmtiEnv *jvmti_env</code>
9492 </description>
9493 </field>
9494 <field id="params">
9495 <allocfieldbuf outcount="param_count">
9496 <struct>jvmtiParamInfo</struct>
9497 </allocfieldbuf>
9498 <description>
9499 Array of
9500 <fieldlink id="param_count" struct="jvmtiExtensionEventInfo"></fieldlink>
9501 parameters (<code>jvmtiEnv *jvmti_env</code> excluded)
9502 </description>
9503 </field>
9504 </typedef>
9505
9506 <description>
9507 Returns the set of extension events.
9508 </description>
9509 <origin>new</origin>
9510 <capabilities>
9511 </capabilities>
9512 <parameters>
9513 <param id="extension_count_ptr">
9514 <outptr><jint/></outptr>
9515 <description>
9516 On return, points to the number of extension events
9517 </description>
9518 </param>
9519 <param id="extensions">
9520 <allocbuf outcount="extension_count_ptr"><struct>jvmtiExtensionEventInfo</struct></allocbuf>
9521 <description>
9522 Returns an array of extension event info, one per event
9523 </description>
9524 </param>
9525 </parameters>
9526 <errors>
9527 </errors>
9528 </function>
9529
9530 <callback id="jvmtiExtensionEvent">
9531 <void/>
9532 <synopsis>Extension Event</synopsis>
9533 <description>
9534 This is the implementation-specific event.
9535 The event handler is set with
9536 <functionlink id="SetExtensionEventCallback"/>.
9537 <p/>
9538 Event handlers for extension events must be declared varargs to match this definition.
9539 Failure to do so could result in calling convention mismatch and undefined behavior
9540 on some platforms.
9541 <p/>
9542 For example, if the <code>jvmtiParamInfo</code>
9543 returned by <functionlink id="GetExtensionEvents"/> indicates that
9544 there is a <code>jint</code> parameter, the event handler should be
9545 declared:
9546 <example>
9547 void JNICALL myHandler(jvmtiEnv* jvmti_env, jint myInt, ...)
9548 </example>
9549 Note the terminal "<code>...</code>" which indicates varargs.
9550 </description>
9551 <parameters>
9552 <param id="jvmti_env">
9553 <outptr>
9554 <struct>jvmtiEnv</struct>
9555 </outptr>
9556 <description>
9557 The <jvmti/> environment is the only fixed parameter for extension events.
9558 </description>
9559 </param>
9560 <param id="...">
9561 <varargs/>
9562 <description>
9563 The extension event-specific parameters
9564 </description>
9565 </param>
9566 </parameters>
9567 </callback>
9568
9569 <function id="SetExtensionEventCallback" phase="onload" num="126">
9570 <synopsis>Set Extension Event Callback</synopsis>
9571
9572 <description>
9573 Sets the callback function for an extension event and
9574 enables the event. Or, if the callback is <code>NULL</code>, disables
9575 the event. Note that unlike standard events, setting
9576 the callback and enabling the event are a single operation.
9577 </description>
9578 <origin>new</origin>
9579 <capabilities>
9580 </capabilities>
9581 <parameters>
9582 <param id="extension_event_index">
9583 <jint/>
9584 <description>
9585 Identifies which callback to set.
9586 This index is the
9587 <fieldlink id="extension_event_index" struct="jvmtiExtensionEventInfo"></fieldlink>
9588 field of
9589 <datalink id="jvmtiExtensionEventInfo"/>.
9590 </description>
9591 </param>
9592 <param id="callback">
9593 <ptrtype>
9594 <struct>jvmtiExtensionEvent</struct>
9595 <nullok>disable the event</nullok>
9596 </ptrtype>
9597 <description>
9598 If <code>callback</code> is non-<code>NULL</code>,
9599 set <code>callback</code> to be the event callback function
9600 and enable the event.
9601 </description>
9602 </param>
9603 </parameters>
9604 <errors>
9605 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
9606 <paramlink id="extension_event_index"/> is not an
9607 <fieldlink id="extension_event_index"
9608 struct="jvmtiExtensionEventInfo"/>
9609 returned by
9610 <functionlink id="GetExtensionEvents"/>
9611 </error>
9612 </errors>
9613 </function>
9614
9615 </category>
9616
9617 <category id="capability" label="Capability">
9618
9619 <intro>
9620 The capabilities functions allow you to change the
9621 functionality available to <jvmti/>--that is,
9622 which <jvmti/>
9623 functions can be called, what events can be generated,
9624 and what functionality these events and functions can
9625 provide.
9626 <p/>
9627 The "Capabilities" section of each function and event describe which
9628 capabilities, if any, they are associated with. "Required Functionality"
9629 means it is available for use and no capabilities must be added to use it.
9630 "Optional Functionality" means the agent must possess the capability
9631 before it can be used.
9632 To possess a capability, the agent must
9633 <functionlink id="AddCapabilities">add the capability</functionlink>.
9634 "Optional Features" describe capabilities which,
9635 if added, extend the feature set.
9636 <p/>
9637 The potentially available capabilities of each <jvmti/> implementation are different.
9638 Depending on the implementation, a capability:
9639 <ul>
9640 <li>may never be added</li>
9641 <li>may be added in either the <code>OnLoad</code> or live phase in any environment</li>
9642 <li>may be added only during the <code>OnLoad</code> phase</li>
9643 <li>may be possessed by only one environment at a time</li>
9644 <li>may be possessed by only one environment at a time,
9645 and only during the <code>OnLoad</code> phase</li>
9646 <li>and so on ...</li>
9647 </ul>
9648 Frequently, the addition of a capability may incur a cost in execution speed, start up
9649 time, and/or memory footprint. Note that the overhead of using a capability
9650 is completely different than the overhead of possessing a capability.
9651 Take single stepping as an example. When single stepping is on (that
9652 is, when the event is enabled and thus actively sending events)
9653 the overhead of sending and processing an event
9654 on each instruction is huge in any implementation.
9655 However, the overhead of possessing the capability may be small or large,
9656 depending on the implementation. Also, when and if a capability is potentially
9657 available depends on the implementation. Some examples:
9658 <ul>
9659 <li>One VM might perform all execution by compiling bytecodes into
9660 native code and be unable to generate single step instructions.
9661 In this implementation the capability can not be added.</li>
9662 <li>Another VM may be able to switch execution to a single stepping
9663 interpreter at any time. In this implementation, having the capability has no
9664 overhead and could be added at any time.</li>
9665 <li>Yet another VM might be able to choose a bytecode compiling or single stepping capable interpreted
9666 execution engine at start up, but be unable to switch between them.
9667 In this implementation the capability would need to be added
9668 during the <code>OnLoad</code> phase (before bytecode
9669 execution begins) and would have a large impact on execution speed
9670 even if single stepping was never used.</li>
9671 <li>Still another VM might be able to add an "is single stepping on" check
9672 into compiled bytecodes or a generated interpreter. Again in this implementation
9673 the capability would need to be added during the <code>OnLoad</code> phase but the overhead (a test
9674 and branch on each instruction) would be considerably less.</li>
9675 </ul>
9676 <p/>
9677 Each <jvmti/> <internallink id="environments">environment</internallink>
9678 has its own set of capabilities.
9679 Initially, that set is empty.
9680 Any desired capability must be added.
9681 If possible, capabilities should be added during the <code>OnLoad</code> phase. For most
9682 virtual machines certain capabilities require special set up for
9683 the virtual machine and this set up must happen
9684 during the <code>OnLoad</code> phase, before the virtual machine begins execution.
9685 Once a capability is added, it can
9686 only be removed if explicitly relinquished by the environment.
9687 <p/>
9688 The agent can,
9689 <functionlink id="GetPotentialCapabilities">determine what
9690 capabilities this VM can potentially provide</functionlink>,
9691 <functionlink id="AddCapabilities">add the capabilities
9692 to be used</functionlink>,
9693 <functionlink id="RelinquishCapabilities">release capabilities
9694 which are no longer needed</functionlink>, and
9695 <functionlink id="GetCapabilities">examine the currently available
9696 capabilities</functionlink>.
9697 </intro>
9698
9699 <intro id="capabilityExamples" label="Capability Examples">
9700 For example, a freshly started agent (in the <code>OnLoad</code> function)
9701 wants to enable all possible capabilities.
9702 Note that, in general, this is not advisable as the agent may suffer
9703 a performance penalty for functionality it is not using.
9704 The code might look like this in C:
9705 <example>
9706 jvmtiCapabilities capa;
9707 jvmtiError err;
9708
9709 err = (*jvmti)->GetPotentialCapabilities(jvmti, &capa);
9710 if (err == JVMTI_ERROR_NONE) {
9711 err = (*jvmti)->AddCapabilities(jvmti, &capa);
9712 </example>
9713 For example, if an agent wants to check if it can get
9714 the bytecodes of a method (that is, it wants to check
9715 if it previously added this capability and has not
9716 relinquished it), the code might
9717 look like this in C:
9718 <example>
9719 jvmtiCapabilities capa;
9720 jvmtiError err;
9721
9722 err = (*jvmti)->GetCapabilities(jvmti, &capa);
9723 if (err == JVMTI_ERROR_NONE) {
9724 if (capa.can_get_bytecodes) { ... } }
9725 </example>
9726 </intro>
9727
9728 <capabilitiestypedef id="jvmtiCapabilities" label="The Capabilities Structure">
9729 <description>
9730 The functions in this category use this capabilities structure
9731 which contains boolean flags corresponding to each capability:
9732 </description>
9733 <capabilityfield id="can_tag_objects">
9734 <description>
9735 Can set and get tags, as described in the
9736 <internallink id="Heap">Heap category</internallink>.
9737 </description>
9738 </capabilityfield>
9739 <capabilityfield id="can_generate_field_modification_events">
9740 <description>
9741 Can set watchpoints on field modification -
9742 <functionlink id="SetFieldModificationWatch"></functionlink>
9743 </description>
9744 </capabilityfield>
9745 <capabilityfield id="can_generate_field_access_events">
9746 <description>
9747 Can set watchpoints on field access -
9748 <functionlink id="SetFieldAccessWatch"></functionlink>
9749 </description>
9750 </capabilityfield>
9751 <capabilityfield id="can_get_bytecodes">
9752 <description>
9753 Can get bytecodes of a method <functionlink id="GetBytecodes"></functionlink>
9754 </description>
9755 </capabilityfield>
9756 <capabilityfield id="can_get_synthetic_attribute">
9757 <description>
9758 Can test if a field or method is synthetic -
9759 <functionlink id="IsFieldSynthetic"></functionlink> and
9760 <functionlink id="IsMethodSynthetic"></functionlink>
9761 </description>
9762 </capabilityfield>
9763 <capabilityfield id="can_get_owned_monitor_info">
9764 <description>
9765 Can get information about ownership of monitors -
9766 <functionlink id="GetOwnedMonitorInfo"></functionlink>
9767 </description>
9768 </capabilityfield>
9769 <capabilityfield id="can_get_current_contended_monitor">
9770 <description>
9771 Can <functionlink id="GetCurrentContendedMonitor"></functionlink>
9772 </description>
9773 </capabilityfield>
9774 <capabilityfield id="can_get_monitor_info">
9775 <description>
9776 Can <functionlink id="GetObjectMonitorUsage"></functionlink>
9777 </description>
9778 </capabilityfield>
9779 <capabilityfield id="can_pop_frame">
9780 <description>
9781 Can pop frames off the stack - <functionlink id="PopFrame"></functionlink>
9782 </description>
9783 </capabilityfield>
9784 <capabilityfield id="can_redefine_classes">
9785 <description>
9786 Can redefine classes with <functionlink id="RedefineClasses"/>.
9787 </description>
9788 </capabilityfield>
9789 <capabilityfield id="can_signal_thread">
9790 <description>
9791 Can send stop or interrupt to threads
9792 </description>
9793 </capabilityfield>
9794 <capabilityfield id="can_get_source_file_name">
9795 <description>
9796 Can get the source file name of a class
9797 </description>
9798 </capabilityfield>
9799 <capabilityfield id="can_get_line_numbers">
9800 <description>
9801 Can get the line number table of a method
9802 </description>
9803 </capabilityfield>
9804 <capabilityfield id="can_get_source_debug_extension">
9805 <description>
9806 Can get the source debug extension of a class
9807 </description>
9808 </capabilityfield>
9809 <capabilityfield id="can_access_local_variables">
9810 <description>
9811 Can set and get local variables
9812 </description>
9813 </capabilityfield>
9814 <capabilityfield id="can_maintain_original_method_order">
9815 <description>
9816 Can return methods in the order they occur in the class file
9817 </description>
9818 </capabilityfield>
9819 <capabilityfield id="can_generate_single_step_events">
9820 <description>
9821 Can get <eventlink id="SingleStep">single step</eventlink> events
9822 </description>
9823 </capabilityfield>
9824 <capabilityfield id="can_generate_exception_events">
9825 <description>
9826 Can get <eventlink id="Exception">exception thrown</eventlink> and
9827 <eventlink id="ExceptionCatch">exception catch</eventlink> events
9828 </description>
9829 </capabilityfield>
9830 <capabilityfield id="can_generate_frame_pop_events">
9831 <description>
9832 Can <functionlink id="NotifyFramePop">set</functionlink> and thus get
9833 <eventlink id="FramePop"></eventlink> events
9834 </description>
9835 </capabilityfield>
9836 <capabilityfield id="can_generate_breakpoint_events">
9837 <description>
9838 Can <functionlink id="SetBreakpoint">set</functionlink> and thus get
9839 <eventlink id="Breakpoint"></eventlink> events
9840 </description>
9841 </capabilityfield>
9842 <capabilityfield id="can_suspend">
9843 <description>
9844 Can suspend and resume threads
9845 </description>
9846 </capabilityfield>
9847 <capabilityfield id="can_redefine_any_class">
9848 <description>
9849 Can modify (retransform or redefine) any non-primitive non-array class.
9850 See <functionlink id="IsModifiableClass"/>.
9851 </description>
9852 </capabilityfield>
9853 <capabilityfield id="can_get_current_thread_cpu_time">
9854 <description>
9855 Can <functionlink id="GetCurrentThreadCpuTime">get</functionlink>
9856 current thread CPU time
9857 </description>
9858 </capabilityfield>
9859 <capabilityfield id="can_get_thread_cpu_time">
9860 <description>
9861 Can <functionlink id="GetThreadCpuTime">get</functionlink>
9862 thread CPU time
9863 </description>
9864 </capabilityfield>
9865 <capabilityfield id="can_generate_method_entry_events"
9866 disp1="can_generate" disp2="_method_entry_events"
9867 >
9868 <description>
9869 Can generate method entry events on entering a method
9870 </description>
9871 </capabilityfield>
9872 <capabilityfield id="can_generate_method_exit_events"
9873 disp1="can_generate" disp2="_method_exit_events"
9874 >
9875 <description>
9876 Can generate method exit events on leaving a method
9877 </description>
9878 </capabilityfield>
9879 <capabilityfield id="can_generate_all_class_hook_events"
9880 disp1="can_generate" disp2="_all_class_hook_events"
9881 >
9882 <description>
9883 Can generate ClassFileLoadHook events for every loaded class.
9884 </description>
9885 </capabilityfield>
9886 <capabilityfield id="can_generate_compiled_method_load_events"
9887 disp1="can_generate" disp2="_compiled_method_load_events"
9888 >
9889 <description>
9890 Can generate events when a method is compiled or unloaded
9891 </description>
9892 </capabilityfield>
9893 <capabilityfield id="can_generate_monitor_events"
9894 disp1="can_generate" disp2="_monitor_events"
9895 >
9896 <description>
9897 Can generate events on monitor activity
9898 </description>
9899 </capabilityfield>
9900 <capabilityfield id="can_generate_vm_object_alloc_events"
9901 disp1="can_generate" disp2="_vm_object_alloc_events"
9902 >
9903 <description>
9904 Can generate events on VM allocation of an object
9905 </description>
9906 </capabilityfield>
9907 <capabilityfield id="can_generate_native_method_bind_events"
9908 disp1="can_generate" disp2="_native_method_bind_events"
9909 >
9910 <description>
9911 Can generate events when a native method is bound to its
9912 implementation
9913 </description>
9914 </capabilityfield>
9915 <capabilityfield id="can_generate_garbage_collection_events"
9916 disp1="can_generate" disp2="_garbage_collection_events"
9917 >
9918 <description>
9919 Can generate events when garbage collection begins or ends
9920 </description>
9921 </capabilityfield>
9922 <capabilityfield id="can_generate_object_free_events"
9923 disp1="can_generate" disp2="_object_free_events"
9924 >
9925 <description>
9926 Can generate events when the garbage collector frees an object
9927 </description>
9928 </capabilityfield>
9929 <capabilityfield id="can_force_early_return" since="1.1">
9930 <description>
9931 Can return early from a method, as described in the
9932 <internallink id="ForceEarlyReturn">Force Early Return category</internallink>.
9933 </description>
9934 </capabilityfield>
9935 <capabilityfield id="can_get_owned_monitor_stack_depth_info" since="1.1">
9936 <description>
9937 Can get information about owned monitors with stack depth -
9938 <functionlink id="GetOwnedMonitorStackDepthInfo"></functionlink>
9939 </description>
9940 </capabilityfield>
9941 <capabilityfield id="can_get_constant_pool" since="1.1">
9942 <description>
9943 Can get the constant pool of a class -
9944 <functionlink id="GetConstantPool"></functionlink>
9945 </description>
9946 </capabilityfield>
9947 <capabilityfield id="can_set_native_method_prefix" since="1.1">
9948 <description>
9949 Can set prefix to be applied when native method cannot be resolved -
9950 <functionlink id="SetNativeMethodPrefix"/> and
9951 <functionlink id="SetNativeMethodPrefixes"/>
9952 </description>
9953 </capabilityfield>
9954 <capabilityfield id="can_retransform_classes" since="1.1">
9955 <description>
9956 Can retransform classes with <functionlink id="RetransformClasses"/>.
9957 In addition to the restrictions imposed by the specific
9958 implementation on this capability (see the
9959 <internallink id="capability">Capability</internallink> section),
9960 this capability must be set before the
9961 <eventlink id="ClassFileLoadHook"/> event is enabled for the
9962 first time in this environment.
9963 An environment that possesses this capability at the time that
9964 <code>ClassFileLoadHook</code> is enabled for the first time is
9965 said to be <i>retransformation capable</i>.
9966 An environment that does not possess this capability at the time that
9967 <code>ClassFileLoadHook</code> is enabled for the first time is
9968 said to be <i>retransformation incapable</i>.
9969 </description>
9970 </capabilityfield>
9971 <capabilityfield id="can_retransform_any_class" since="1.1">
9972 <description>
9973 <functionlink id="RetransformClasses"/> can be called on any class
9974 (<fieldlink id="can_retransform_classes" struct="jvmtiCapabilities"/>
9975 must also be set)
9976 </description>
9977 </capabilityfield>
9978 <capabilityfield id="can_generate_resource_exhaustion_heap_events" since="1.1">
9979 <description>
9980 Can generate events when the VM is unable to allocate memory from
9981 the <tm>Java</tm> platform heap.
9982 See <eventlink id="ResourceExhausted"/>.
9983 </description>
9984 </capabilityfield>
9985 <capabilityfield id="can_generate_resource_exhaustion_threads_events" since="1.1">
9986 <description>
9987 Can generate events when the VM is unable to create a thread.
9988 See <eventlink id="ResourceExhausted"/>.
9989 </description>
9990 </capabilityfield>
9991 <capabilityfield id="can_generate_early_vmstart" since="9">
9992 <description>
9993 Can generate the <code>VMStart</code> event early.
9994 See <eventlink id="VMStart"/>.
9995 </description>
9996 </capabilityfield>
9997 </capabilitiestypedef>
9998
9999 <function id="GetPotentialCapabilities" jkernel="yes" phase="onload" num="140">
10000 <synopsis>Get Potential Capabilities</synopsis>
10001 <description>
10002 Returns via <paramlink id="capabilities_ptr"></paramlink> the <jvmti/>
10003 features that can potentially be possessed by this environment
10004 at this time.
10005 The returned capabilities differ from the complete set of capabilities
10006 implemented by the VM in two cases: another environment possesses
10007 capabilities that can only be possessed by one environment, or the
10008 current <functionlink id="GetPhase">phase</functionlink> is live,
10009 and certain capabilities can only be added during the <code>OnLoad</code> phase.
10010 The <functionlink id="AddCapabilities"></functionlink> function
10011 may be used to set any or all or these capabilities.
10012 Currently possessed capabilities are included.
10013 <p/>
10014 Typically this function is used in the <code>OnLoad</code> function.
10015 Some virtual machines may allow a limited set of capabilities to be
10016 added in the live phase.
10017 In this case, the set of potentially available capabilities
10018 will likely differ from the <code>OnLoad</code> phase set.
10019 <p/>
10020 See the
10021 <internallink id="capabilityExamples">Capability Examples</internallink>.
10022 </description>
10023 <origin>new</origin>
10024 <capabilities>
10025 </capabilities>
10026 <parameters>
10027 <param id="capabilities_ptr">
10028 <outptr><struct>jvmtiCapabilities</struct></outptr>
10029 <description>
10030 On return, points to the <jvmti/> capabilities that may be added.
10031 </description>
10032 </param>
10033 </parameters>
10034 <errors>
10035 </errors>
10036 </function>
10037
10038 <elide>
10039 <function id="EstimateCostOfCapabilities" phase="onload" num="141">
10040 <synopsis>Estimate Cost Of Capabilities</synopsis>
10041 <description>
10042 <issue>There is strong opposition to this function. The concern is
10043 that it would be difficult or impossible to provide meaningful
10044 numbers, as the amount of impact is conditional on many factors
10045 that a single number could not represent. There is doubt that
10046 conditional implementations would be used or are even a good idea.
10047 The thought is that release documentation for the implementation
10048 would be the best means of exposing this information.
10049 Unless new arguments are presented, I intend to remove this
10050 function in the next revision.
10051 </issue>
10052 <p/>
10053 Return via the <paramlink id="time_impact_ptr"></paramlink> and
10054 <paramlink id="space_impact_ptr"></paramlink> an estimate of the impact
10055 of adding the capabilities pointed to by
10056 <paramlink id="capabilities_ptr"></paramlink>.
10057 The returned estimates are in percentage of additional overhead, thus
10058 a time impact of 100 mean the application might run
10059 at half the speed.
10060 The estimates are very rough approximations and are not guaranteed.
10061 Note also, that the estimates are of the impact of having the
10062 capability available--when and if it is used the impact may be
10063 much greater.
10064 Estimates can be for a single capability or for a set of
10065 capabilities. Note that the costs are not necessarily additive,
10066 adding support for one capability might make another available
10067 for free or conversely having two capabilities at once may
10068 have multiplicative impact.
10069 Estimates are relative to the current set of capabilities -
10070 that is, how much more impact given the currently possessed capabilities.
10071 <p/>
10072 Typically this function is used in the OnLoad function,
10073 some virtual machines may allow a limited set of capabilities to be
10074 added in the live phase.
10075 In this case, the set of potentially available capabilities
10076 will likely differ from the OnLoad phase set.
10077 <p/>
10078 See the
10079 <internallink id="capabilityExamples">Capability Examples</internallink>.
10080 </description>
10081 <origin>new</origin>
10082 <capabilities>
10083 </capabilities>
10084 <parameters>
10085 <param id="capabilities_ptr">
10086 <inptr><struct>jvmtiCapabilities</struct></inptr>
10087 <description>
10088 points to the <jvmti/> capabilities to evaluate.
10089 </description>
10090 </param>
10091 <param id="time_impact_ptr">
10092 <outptr><jint/></outptr>
10093 <description>
10094 On return, points to the estimated percentage increase in
10095 run time if this capability was added.
10096 </description>
10097 </param>
10098 <param id="space_impact_ptr">
10099 <outptr><jint/></outptr>
10100 <description>
10101 On return, points to the estimated percentage increase in
10102 memory space used if this capability was added.
10103 </description>
10104 </param>
10105 </parameters>
10106 <errors>
10107 <error id="JVMTI_ERROR_NOT_AVAILABLE">
10108 The desired capabilities are not even potentially available.
10109 </error>
10110 </errors>
10111 </function>
10112 </elide>
10113
10114 <function id="AddCapabilities" jkernel="yes" phase="onload" num="142">
10115 <synopsis>Add Capabilities</synopsis>
10116 <description>
10117 Set new capabilities by adding the capabilities
10118 whose values are set to one (<code>1</code>) in
10119 <code>*</code><paramlink id="capabilities_ptr"></paramlink>.
10120 All previous capabilities are retained.
10121 Typically this function is used in the <code>OnLoad</code> function.
10122 Some virtual machines may allow a limited set of capabilities to be
10123 added in the live phase.
10124 <p/>
10125 See the
10126 <internallink id="capabilityExamples">Capability Examples</internallink>.
10127 </description>
10128 <origin>new</origin>
10129 <capabilities>
10130 </capabilities>
10131 <parameters>
10132 <param id="capabilities_ptr">
10133 <inptr><struct>jvmtiCapabilities</struct></inptr>
10134 <description>
10135 Points to the <jvmti/> capabilities to add.
10136 </description>
10137 </param>
10138 </parameters>
10139 <errors>
10140 <error id="JVMTI_ERROR_NOT_AVAILABLE">
10141 The desired capabilities are not even potentially available.
10142 </error>
10143 </errors>
10144 </function>
10145
10146
10147 <function id="RelinquishCapabilities" phase="onload" num="143">
10148 <synopsis>Relinquish Capabilities</synopsis>
10149 <description>
10150 Relinquish the capabilities
10151 whose values are set to one (<code>1</code>) in
10152 <code>*</code><paramlink id="capabilities_ptr"></paramlink>.
10153 Some implementations may allow only one environment to have a capability
10154 (see the <internallink id="capability">capability introduction</internallink>).
10155 This function releases capabilities
10156 so that they may be used by other agents.
10157 All other capabilities are retained.
10158 The capability will no longer be present in <functionlink id="GetCapabilities"></functionlink>.
10159 Attempting to relinquish a capability that the agent does not possess is not an error.
10160 <issue>
10161 It is possible for the agent to be actively using capabilities
10162 which are being relinquished. For example, a thread is currently
10163 suspended and can_suspend is being relinquished or an event is currently
10164 enabled and can_generate_whatever is being relinquished.
10165 There are three possible ways we could spec this:
10166 <ul>
10167 <li>relinquish automatically releases them</li>
10168 <li>relinquish checks and returns some error code if held</li>
10169 <li>it is the agent's responsibility and it is not checked</li>
10170 </ul>
10171 One of these should be chosen.
10172 </issue>
10173 </description>
10174 <origin>new</origin>
10175 <capabilities>
10176 </capabilities>
10177 <parameters>
10178 <param id="capabilities_ptr">
10179 <inptr><struct>jvmtiCapabilities</struct></inptr>
10180 <description>
10181 Points to the <jvmti/> capabilities to relinquish.
10182 </description>
10183 </param>
10184 </parameters>
10185 <errors>
10186 </errors>
10187 </function>
10188
10189
10190
10191 <function id="GetCapabilities" jkernel="yes" phase="any" num="89">
10192 <synopsis>Get Capabilities</synopsis>
10193 <description>
10194 Returns via <paramlink id="capabilities_ptr"></paramlink> the optional <jvmti/>
10195 features which this environment currently possesses.
10196 Each possessed capability is indicated by a one (<code>1</code>) in the
10197 corresponding field of the <internallink id="jvmtiCapabilities">capabilities
10198 structure</internallink>.
10199 An environment does not possess a capability unless it has been successfully added with
10200 <functionlink id="AddCapabilities"/>.
10201 An environment only loses possession of a capability if it has been relinquished with
10202 <functionlink id="RelinquishCapabilities"/>. Thus, this function returns the net result
10203 of the <code>AddCapabilities</code> and <code>RelinquishCapabilities</code> calls which
10204 have been made.
10205 <p/>
10206 See the
10207 <internallink id="capabilityExamples">Capability Examples</internallink>.
10208 </description>
10209 <origin>jvmdiClone</origin>
10210 <capabilities>
10211 </capabilities>
10212 <parameters>
10213 <param id="capabilities_ptr">
10214 <outptr><struct>jvmtiCapabilities</struct></outptr>
10215 <description>
10216 On return, points to the <jvmti/> capabilities.
10217 </description>
10218 </param>
10219 </parameters>
10220 <errors>
10221 </errors>
10222 </function>
10223
10224 </category>
10225
10226
10227 <category id="timers" label="Timers">
10228
10229 <intro>
10230 These functions provide timing information.
10231 The resolution at which the time is updated is not specified.
10232 They provides nanosecond precision, but not necessarily nanosecond accuracy.
10233 Details about the timers, such as their maximum values, can be accessed with
10234 the timer information functions.
10235 </intro>
10236
10237 <typedef id="jvmtiTimerInfo" label="Timer Info">
10238 <description>
10239 The information function for each timer returns this data structure.
10240 </description>
10241 <field id="max_value">
10242 <jlong/>
10243 <description>
10244 The maximum value the timer can reach.
10245 After this value is reached the timer wraps back to zero.
10246 This is an unsigned value. If tested or printed as a jlong (signed value)
10247 it may appear to be a negative number.
10248 </description>
10249 </field>
10250 <field id="may_skip_forward">
10251 <jboolean/>
10252 <description>
10253 If true, the timer can be externally adjusted and as a result skip forward.
10254 If false, the timer value will never increase faster than real time.
10255 </description>
10256 </field>
10257 <field id="may_skip_backward">
10258 <jboolean/>
10259 <description>
10260 If true, the timer can be externally adjusted and as a result skip backward.
10261 If false, the timer value will be monotonically increasing.
10262 </description>
10263 </field>
10264 <field id="kind">
10265 <enum>jvmtiTimerKind</enum>
10266 <description>
10267 The kind of timer.
10268 On a platform that does not distinguish between user and system time, <datalink
10269 id="JVMTI_TIMER_TOTAL_CPU"><code>JVMTI_TIMER_TOTAL_CPU</code></datalink>
10270 is returned.
10271 </description>
10272 </field>
10273 <field id="reserved1">
10274 <jlong/>
10275 <description>
10276 Reserved for future use.
10277 </description>
10278 </field>
10279 <field id="reserved2">
10280 <jlong/>
10281 <description>
10282 Reserved for future use.
10283 </description>
10284 </field>
10285 </typedef>
10286
10287 <intro>
10288 Where the timer kind is --
10289
10290 <constants id="jvmtiTimerKind" label="Timer Kinds" kind="enum">
10291 <constant id="JVMTI_TIMER_USER_CPU" num="30">
10292 CPU time that a thread is in user mode.
10293 </constant>
10294 <constant id="JVMTI_TIMER_TOTAL_CPU" num="31">
10295 CPU time that a thread is in user or system mode.
10296 </constant>
10297 <constant id="JVMTI_TIMER_ELAPSED" num="32">
10298 Elapsed time.
10299 </constant>
10300 </constants>
10301 </intro>
10302
10303 <function id="GetCurrentThreadCpuTimerInfo" callbacksafe="safe" impl="innative notrace" phase="start" num="134">
10304 <synopsis>Get Current Thread CPU Timer Information</synopsis>
10305 <description>
10306 Get information about the
10307 <functionlink id="GetCurrentThreadCpuTime"/> timer.
10308 The fields of the <datalink id="jvmtiTimerInfo"/> structure
10309 are filled in with details about the timer.
10310 This information is specific to the platform and the implementation of
10311 <functionlink id="GetCurrentThreadCpuTime"/> and thus
10312 does not vary by thread nor does it vary
10313 during a particular invocation of the VM.
10314 <p/>
10315 Note that the implementations of <functionlink id="GetCurrentThreadCpuTime"/>
10316 and <functionlink id="GetThreadCpuTime"/> may differ, and thus the values
10317 returned by <code>GetCurrentThreadCpuTimerInfo</code>
10318 and <functionlink id="GetThreadCpuTimerInfo"/>
10319 may differ -- see <functionlink id="GetCurrentThreadCpuTime"/> for more information.
10320 </description>
10321 <origin>new</origin>
10322 <capabilities>
10323 <required id="can_get_current_thread_cpu_time">
10324 Can get current thread CPU time.
10325 </required>
10326 </capabilities>
10327 <parameters>
10328 <param id="info_ptr">
10329 <outptr><struct>jvmtiTimerInfo</struct></outptr>
10330 <description>
10331 On return, filled with information describing the time
10332 returned by <functionlink id="GetCurrentThreadCpuTime"/>.
10333 </description>
10334 </param>
10335 </parameters>
10336 <errors>
10337 </errors>
10338 </function>
10339
10340 <function id="GetCurrentThreadCpuTime" callbacksafe="safe" impl="innative notrace" phase="start" num="135">
10341 <synopsis>Get Current Thread CPU Time</synopsis>
10342 <description>
10343 Return the CPU time utilized by the current thread.
10344 <p/>
10345 Note that the <functionlink id="GetThreadCpuTime"/>
10346 function provides CPU time for any thread, including
10347 the current thread. <code>GetCurrentThreadCpuTime</code>
10348 exists to support platforms which cannot
10349 supply CPU time for threads other than the current
10350 thread or which have more accurate information for
10351 the current thread (see
10352 <functionlink id="GetCurrentThreadCpuTimerInfo"/> vs
10353 <functionlink id="GetThreadCpuTimerInfo"/>).
10354 On many platforms this call will be equivalent to:
10355 <example>
10356 GetThreadCpuTime(env, NULL, nanos_ptr)
10357 </example>
10358 </description>
10359 <origin>new</origin>
10360 <capabilities>
10361 <required id="can_get_current_thread_cpu_time">
10362 Can get current thread CPU time.
10363 <p/>
10364 If this capability is enabled after threads have started,
10365 the implementation may choose any time up
10366 to and including the time that the capability is enabled
10367 as the point where CPU time collection starts.
10368 <p/>
10369 This capability must be potentially available on any
10370 platform where
10371 <internallink id="jvmtiCapabilities.can_get_thread_cpu_time"><code>can_get_thread_cpu_time</code></internallink>
10372 is potentially available.
10373 </required>
10374 </capabilities>
10375 <parameters>
10376 <param id="nanos_ptr">
10377 <outptr><jlong/></outptr>
10378 <description>
10379 On return, points to the CPU time used by this thread
10380 in nanoseconds.
10381 This is an unsigned value. If tested or printed as a jlong (signed value)
10382 it may appear to be a negative number.
10383 </description>
10384 </param>
10385 </parameters>
10386 <errors>
10387 </errors>
10388 </function>
10389
10390 <function id="GetThreadCpuTimerInfo" num="136">
10391 <synopsis>Get Thread CPU Timer Information</synopsis>
10392 <description>
10393 Get information about the
10394 <functionlink id="GetThreadCpuTime"/> timer.
10395 The fields of the <datalink id="jvmtiTimerInfo"/> structure
10396 are filled in with details about the timer.
10397 This information is specific to the platform and the implementation of
10398 <functionlink id="GetThreadCpuTime"/> and thus
10399 does not vary by thread nor does it vary
10400 during a particular invocation of the VM.
10401 <p/>
10402 Note that the implementations of <functionlink id="GetCurrentThreadCpuTime"/>
10403 and <functionlink id="GetThreadCpuTime"/> may differ, and thus the values
10404 returned by <functionlink id="GetCurrentThreadCpuTimerInfo"/>
10405 and <code>GetThreadCpuTimerInfo</code>
10406 may differ -- see <functionlink id="GetCurrentThreadCpuTime"/> for more information.
10407 </description>
10408 <origin>new</origin>
10409 <capabilities>
10410 <required id="can_get_thread_cpu_time">
10411 Can get thread CPU time.
10412 </required>
10413 </capabilities>
10414 <parameters>
10415 <param id="info_ptr">
10416 <outptr><struct>jvmtiTimerInfo</struct></outptr>
10417 <description>
10418 On return, filled with information describing the time
10419 returned by <functionlink id="GetThreadCpuTime"/>.
10420 </description>
10421 </param>
10422 </parameters>
10423 <errors>
10424 </errors>
10425 </function>
10426
10427 <function id="GetThreadCpuTime" num="137">
10428 <synopsis>Get Thread CPU Time</synopsis>
10429 <description>
10430 Return the CPU time utilized by the specified thread.
10431 <p/>
10432 Get information about this timer with
10433 <functionlink id="GetThreadCpuTimerInfo"/>.
10434 </description>
10435 <origin>new</origin>
10436 <capabilities>
10437 <required id="can_get_thread_cpu_time">
10438 Can get thread CPU time.
10439 <p/>
10440 If this capability is enabled after threads have started,
10441 the implementation may choose any time up
10442 to and including the time that the capability is enabled
10443 as the point where CPU time collection starts.
10444 </required>
10445 </capabilities>
10446 <parameters>
10447 <param id="thread">
10448 <jthread null="current"/>
10449 <description>
10450 The thread to query.
10451 </description>
10452 </param>
10453 <param id="nanos_ptr">
10454 <outptr><jlong/></outptr>
10455 <description>
10456 On return, points to the CPU time used by the specified thread
10457 in nanoseconds.
10458 This is an unsigned value. If tested or printed as a jlong (signed value)
10459 it may appear to be a negative number.
10460 </description>
10461 </param>
10462 </parameters>
10463 <errors>
10464 </errors>
10465 </function>
10466
10467 <function id="GetTimerInfo" phase="any" callbacksafe="safe" num="138">
10468 <synopsis>Get Timer Information</synopsis>
10469 <description>
10470 Get information about the
10471 <functionlink id="GetTime"/> timer.
10472 The fields of the <datalink id="jvmtiTimerInfo"/> structure
10473 are filled in with details about the timer.
10474 This information will not change during a particular invocation of the VM.
10475 </description>
10476 <origin>new</origin>
10477 <capabilities>
10478 </capabilities>
10479 <parameters>
10480 <param id="info_ptr">
10481 <outptr><struct>jvmtiTimerInfo</struct></outptr>
10482 <description>
10483 On return, filled with information describing the time
10484 returned by <functionlink id="GetTime"/>.
10485 </description>
10486 </param>
10487 </parameters>
10488 <errors>
10489 </errors>
10490 </function>
10491
10492 <function id="GetTime" phase="any" callbacksafe="safe" num="139">
10493 <synopsis>Get Time</synopsis>
10494 <description>
10495 Return the current value of the system timer, in nanoseconds.
10496 <p/>
10497 The value returned represents nanoseconds since some fixed but
10498 arbitrary time (perhaps in the future, so values may be
10499 negative). This function provides nanosecond precision, but not
10500 necessarily nanosecond accuracy. No guarantees are made about
10501 how frequently values change.
10502 <p/>
10503 Get information about this timer with
10504 <functionlink id="GetTimerInfo"/>.
10505 </description>
10506 <origin>new</origin>
10507 <capabilities>
10508 </capabilities>
10509 <parameters>
10510 <param id="nanos_ptr">
10511 <outptr><jlong/></outptr>
10512 <description>
10513 On return, points to the time in nanoseconds.
10514 This is an unsigned value. If tested or printed as a jlong (signed value)
10515 it may appear to be a negative number.
10516 </description>
10517 </param>
10518 </parameters>
10519 <errors>
10520 </errors>
10521 </function>
10522
10523 <function id="GetAvailableProcessors" phase="any" num="144">
10524 <synopsis>Get Available Processors</synopsis>
10525 <description>
10526 Returns the number of processors available to the Java virtual machine.
10527 <p/>
10528 This value may change during a particular invocation of the virtual machine.
10529 Applications that are sensitive to the number of available processors should
10530 therefore occasionally poll this property.
10531 </description>
10532 <origin>new</origin>
10533 <capabilities>
10534 </capabilities>
10535 <parameters>
10536 <param id="processor_count_ptr">
10537 <outptr><jint/></outptr>
10538 <description>
10539 On return, points to the maximum number of processors available to the
10540 virtual machine; never smaller than one.
10541 </description>
10542 </param>
10543 </parameters>
10544 <errors>
10545 </errors>
10546 </function>
10547
10548 </category>
10549
10550
10551 <category id="classLoaderSearch" label="Class Loader Search">
10552
10553 <intro>
10554 These functions allow the agent to add to the locations that a class loader searches for a class.
10555 This is useful for installing instrumentation under the correct class loader.
10556 </intro>
10557
10558 <function id="AddToBootstrapClassLoaderSearch" jkernel="yes" phase="onload" num="149">
10559 <synopsis>Add To Bootstrap Class Loader Search</synopsis>
10560 <description>
10561 This function can be used to cause instrumentation classes to be defined by the
10562 bootstrap class loader. See <vmspec chapter="5.3.1"/>.
10563 After the bootstrap
10564 class loader unsuccessfully searches for a class, the specified platform-dependent
10565 search path <paramlink id="segment"/> will be searched as well. Only one segment may be specified in
10566 the <paramlink id="segment"/>. This function may be called multiple times to add multiple segments,
10567 the segments will be searched in the order that this function was called.
10568 <p/>
10569 In the <code>OnLoad</code> phase the function may be used to specify any platform-dependent
10570 search path segment to be searched after the bootstrap class loader unsuccessfully searches
10571 for a class. The segment is typically a directory or JAR file.
10572 <p/>
10573 In the live phase the <paramlink id="segment"/> may be used to specify any platform-dependent
10574 path to a <externallink id="http://docs.oracle.com/javase/7/docs/technotes/guides/jar/jar.html">
10575 JAR file</externallink>. The agent should take care that the JAR file does not
10576 contain any classes or resources other than those to be defined by the bootstrap
10577 class loader for the purposes of instrumentation.
10578 <p/>
10579 <vmspec/> specifies that a subsequent attempt to resolve a symbolic
10580 reference that the Java virtual machine has previously unsuccessfully attempted
10581 to resolve always fails with the same error that was thrown as a result of the
10582 initial resolution attempt. Consequently, if the JAR file contains an entry
10583 that corresponds to a class for which the Java virtual machine has
10584 unsuccessfully attempted to resolve a reference, then subsequent attempts to
10585 resolve that reference will fail with the same error as the initial attempt.
10586 </description>
10587 <origin>new</origin>
10588 <capabilities>
10589 </capabilities>
10590 <parameters>
10591 <param id="segment">
10592 <inbuf><char/></inbuf>
10593 <description>
10594 The platform-dependent search path segment, encoded as a
10595 <internallink id="mUTF">modified UTF-8</internallink> string.
10596 </description>
10597 </param>
10598 </parameters>
10599 <errors>
10600 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
10601 <paramlink id="segment"/> is an invalid path. In the live phase, anything other than an
10602 existing JAR file is an invalid path.
10603 </error>
10604 </errors>
10605 </function>
10606
10607 <function id="AddToSystemClassLoaderSearch" jkernel="yes" phase="onload" num="151" since="1.1">
10608 <synopsis>Add To System Class Loader Search</synopsis>
10609 <description>
10610 This function can be used to cause instrumentation classes to be
10611 defined by the system class loader. See <vmspec chapter="5.3.2"/>.
10612 After the class loader unsuccessfully searches for a class, the specified platform-dependent search
10613 path <paramlink id="segment"/> will be searched as well. Only one segment may be specified in the
10614 <paramlink id="segment"/>. This function may be called multiple times to add multiple segments, the
10615 segments will be searched in the order that this function was called.
10616 <p/>
10617 In the <code>OnLoad</code> phase the function may be used to specify any platform-dependent
10618 search path segment to be searched after the system class loader unsuccessfully searches
10619 for a class. The segment is typically a directory or JAR file.
10620 <p/>
10621 In the live phase the <paramlink id="segment"/> is a platform-dependent path to a <externallink
10622 id="http://docs.oracle.com/javase/7/docs/technotes/guides/jar/jar.html">JAR file</externallink> to be
10623 searched after the system class loader unsuccessfully searches for a class. The agent should
10624 take care that the JAR file does not contain any classes or resources other than those to be
10625 defined by the system class loader for the purposes of instrumentation.
10626 <p/>
10627 In the live phase the system class loader supports adding a JAR file to be searched if
10628 the system class loader implements a method name <code>appendToClassPathForInstrumentation</code>
10629 which takes a single parameter of type <code>java.lang.String</code>. The method is not required
10630 to have <code>public</code> access.
10631 <p/>
10632 <vmspec/> specifies that a subsequent attempt to resolve a symbolic
10633 reference that the Java virtual machine has previously unsuccessfully attempted
10634 to resolve always fails with the same error that was thrown as a result of the
10635 initial resolution attempt. Consequently, if the JAR file contains an entry
10636 that corresponds to a class for which the Java virtual machine has
10637 unsuccessfully attempted to resolve a reference, then subsequent attempts to
10638 resolve that reference will fail with the same error as the initial attempt.
10639 </description>
10640 <origin>new</origin>
10641 <capabilities>
10642 </capabilities>
10643 <parameters>
10644 <param id="segment">
10645 <inbuf><char/></inbuf>
10646 <description>
10647 The platform-dependent search path segment, encoded as a
10648 <internallink id="mUTF">modified UTF-8</internallink> string.
10649 </description>
10650 </param>
10651 </parameters>
10652 <errors>
10653 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
10654 <paramlink id="segment"/> is an invalid path. In the live phase, anything other than an
10655 existing JAR file is an invalid path.
10656 </error>
10657 <error id="JVMTI_ERROR_CLASS_LOADER_UNSUPPORTED">
10658 Operation not supported by the system class loader.
10659 </error>
10660 </errors>
10661 </function>
10662
10663 </category>
10664
10665
10666 <category id="props" label="System Properties">
10667
10668 <intro>
10669 These functions get and set system properties.
10670 </intro>
10671
10672 <function id="GetSystemProperties" phase="onload" num="130">
10673 <synopsis>Get System Properties</synopsis>
10674 <description>
10675 The list of VM system property keys which may be used with
10676 <functionlink id="GetSystemProperty"/> is returned.
10677 It is strongly recommended that virtual machines provide the
10678 following property keys:
10679 <ul>
10680 <li><code>java.vm.vendor</code></li>
10681 <li><code>java.vm.version</code></li>
10682 <li><code>java.vm.name</code></li>
10683 <li><code>java.vm.info</code></li>
10684 <li><code>java.library.path</code></li>
10685 <li><code>java.class.path</code></li>
10686 </ul>
10687 Provides access to system properties defined by and used
10688 by the VM.
10689 Properties set on the command-line are included.
10690 This allows getting and setting of these properties
10691 before the VM even begins executing bytecodes.
10692 Since this is a VM view of system properties, the set of available
10693 properties will usually be different than that
10694 in <code>java.lang.System.getProperties</code>.
10695 JNI method invocation may be used to access
10696 <code>java.lang.System.getProperties</code>.
10697 <p/>
10698 The set of properties may grow during execution.
10699 </description>
10700 <origin>new</origin>
10701 <capabilities>
10702 </capabilities>
10703 <parameters>
10704 <param id="count_ptr">
10705 <outptr><jint/></outptr>
10706 <description>
10707 On return, points to the number of property keys returned.
10708 </description>
10709 </param>
10710 <param id="property_ptr">
10711 <allocallocbuf outcount="count_ptr"><char/></allocallocbuf>
10712 <description>
10713 On return, points to an array of property keys, encoded as
10714 <internallink id="mUTF">modified UTF-8</internallink> strings.
10715 </description>
10716 </param>
10717 </parameters>
10718 <errors>
10719 </errors>
10720 </function>
10721
10722 <function id="GetSystemProperty" phase="onload" num="131">
10723 <synopsis>Get System Property</synopsis>
10724 <description>
10725 Return a VM system property value given the property key.
10726 <p/>
10727 The function <functionlink id="GetSystemProperties"/>
10728 returns the set of property keys which may be used.
10729 The properties which can be retrieved may grow during
10730 execution.
10731 <p/>
10732 Since this is a VM view of system properties, the values
10733 of properties may differ from that returned by
10734 <code>java.lang.System.getProperty(String)</code>.
10735 A typical VM might copy the values of the VM system
10736 properties into the <code>Properties</code> held by
10737 <code>java.lang.System</code> during the initialization
10738 of that class. Thereafter any changes to the VM system
10739 properties (with <functionlink id="SetSystemProperty"/>)
10740 or the <code>java.lang.System</code> system properties
10741 (with <code>java.lang.System.setProperty(String,String)</code>)
10742 would cause the values to diverge.
10743 JNI method invocation may be used to access
10744 <code>java.lang.System.getProperty(String)</code>.
10745 </description>
10746 <origin>new</origin>
10747 <capabilities>
10748 </capabilities>
10749 <parameters>
10750 <param id="property">
10751 <inbuf><char/></inbuf>
10752 <description>
10753 The key of the property to retrieve, encoded as a
10754 <internallink id="mUTF">modified UTF-8</internallink> string.
10755 </description>
10756 </param>
10757 <param id="value_ptr">
10758 <allocbuf><char/></allocbuf>
10759 <description>
10760 On return, points to the property value, encoded as a
10761 <internallink id="mUTF">modified UTF-8</internallink> string.
10762 </description>
10763 </param>
10764 </parameters>
10765 <errors>
10766 <error id="JVMTI_ERROR_NOT_AVAILABLE">
10767 This property is not available.
10768 Use <functionlink id="GetSystemProperties"/> to find available properties.
10769 </error>
10770 </errors>
10771 </function>
10772
10773 <function id="SetSystemProperty" phase="onloadOnly" num="132">
10774 <synopsis>Set System Property</synopsis>
10775 <description>
10776 Set a VM system property value.
10777 <p/>
10778 The function <functionlink id="GetSystemProperties"/>
10779 returns the set of property keys, some of these may be settable.
10780 See <functionlink id="GetSystemProperty"/>.
10781 </description>
10782 <origin>new</origin>
10783 <capabilities>
10784 </capabilities>
10785 <parameters>
10786 <param id="property">
10787 <inbuf><char/></inbuf>
10788 <description>
10789 The key of the property, encoded as a
10790 <internallink id="mUTF">modified UTF-8</internallink> string.
10791 </description>
10792 </param>
10793 <param id="value_ptr">
10794 <inbuf>
10795 <char/>
10796 <nullok>
10797 do not set the value, but return <errorlink id="JVMTI_ERROR_NOT_AVAILABLE"/>
10798 if the property is not writeable
10799 </nullok>
10800 </inbuf>
10801 <description>
10802 The property value to set, encoded as a
10803 <internallink id="mUTF">modified UTF-8</internallink> string.
10804 </description>
10805 </param>
10806 </parameters>
10807 <errors>
10808 <error id="JVMTI_ERROR_NOT_AVAILABLE">
10809 This property is not available or is not writeable.
10810 </error>
10811 </errors>
10812 </function>
10813
10814 </category>
10815
10816 <category id="general" label="General">
10817
10818 <intro>
10819 </intro>
10820
10821 <function id="GetPhase" jkernel="yes" phase="any" num="133">
10822 <synopsis>Get Phase</synopsis>
10823 <description>
10824 Return the current phase of VM execution.
10825 The phases proceed in sequence:
10826 <constants id="jvmtiPhase" label="Phases of execution" kind="enum">
10827 <constant id="JVMTI_PHASE_ONLOAD" num="1">
10828 <code>OnLoad</code> phase: while in the
10829 <internallink id="onload"><code>Agent_OnLoad</code></internallink>
10830 or, for statically linked agents, the <internallink id="onload">
10831 <code>Agent_OnLoad_<agent-lib-name>
10832 </code></internallink> function.
10833 </constant>
10834 <constant id="JVMTI_PHASE_PRIMORDIAL" num="2">
10835 Primordial phase: between return from <code>Agent_OnLoad</code>
10836 or <code>Agent_OnLoad_<agent-lib-name></code> and the
10837 <code>VMStart</code> event.
10838 </constant>
10839 <constant id="JVMTI_PHASE_START" num="6">
10840 Start phase: when the <eventlink id="VMStart"><code>VMStart</code></eventlink> event
10841 is sent and until the <code>VMInit</code> event is sent.
10842 </constant>
10843 <constant id="JVMTI_PHASE_LIVE" num="4">
10844 Live phase: when the <eventlink id="VMInit"><code>VMInit</code></eventlink> event is sent
10845 and until the <eventlink id="VMDeath"></eventlink> event returns.
10846 </constant>
10847 <constant id="JVMTI_PHASE_DEAD" num="8">
10848 Dead phase: after the <eventlink id="VMDeath"></eventlink> event returns or after
10849 start-up failure.
10850 </constant>
10851 </constants>
10852 In the case of start-up failure the VM will proceed directly to the dead
10853 phase skipping intermediate phases and neither a <code>VMInit</code> nor
10854 <code>VMDeath</code> event will be sent.
10855 <p/>
10856 Most <jvmti/> functions operate only in the live phase.
10857 The following functions operate in either the <code>OnLoad</code> or live phases:
10858 <functionphaselist phase="onload"/>
10859 The following functions operate in only the <code>OnLoad</code> phase:
10860 <functionphaselist phase="onloadOnly"/>
10861 The following functions operate in the start or live phases:
10862 <functionphaselist phase="start"/>
10863 The following functions operate in any phase:
10864 <functionphaselist phase="any"/>
10865 JNI functions (except the Invocation API) must only be used in the start or live phases.
10866 <p/>
10867 Most <jvmti/> events are sent only in the live phase.
10868 The following events operate in others phases:
10869 <eventphaselist phase="start"/>
10870 <eventphaselist phase="any"/>
10871 </description>
10872 <origin>new</origin>
10873 <capabilities>
10874 </capabilities>
10875 <parameters>
10876 <param id="phase_ptr">
10877 <outptr><enum>jvmtiPhase</enum></outptr>
10878 <description>
10879 On return, points to the phase.
10880 </description>
10881 </param>
10882 </parameters>
10883 <errors>
10884 </errors>
10885 </function>
10886
10887 <function id="DisposeEnvironment" jkernel="yes" phase="any" num="127">
10888 <synopsis>Dispose Environment</synopsis>
10889 <description>
10890 Shutdown a <jvmti/> connection created with JNI <code>GetEnv</code>
10891 (see <internallink id="environments"><jvmti/> Environments</internallink>).
10892 Dispose of any resources held by the environment.
10893 <issue>
10894 What resources are reclaimed? What is undone?
10895 Breakpoints,watchpoints removed?
10896 </issue>
10897 Threads suspended by this environment are not resumed by this call,
10898 this must be done explicitly by the agent.
10899 Memory allocated by this environment via calls to <jvmti/> functions
10900 is not released, this can be done explicitly by the agent
10901 by calling <functionlink id="Deallocate"/>.
10902 Raw monitors created by this environment are not destroyed,
10903 this can be done explicitly by the agent
10904 by calling <functionlink id="DestroyRawMonitor"/>.
10905 The state of threads waiting on raw monitors created by this environment
10906 are not affected.
10907 <p/>
10908 Any <functionlink id="SetNativeMethodPrefix">native method
10909 prefixes</functionlink> for this environment will be unset;
10910 the agent must remove any prefixed native methods before
10911 dispose is called.
10912 <p/>
10913 Any <internallink id="capability">capabilities</internallink>
10914 held by this environment are relinquished.
10915 <p/>
10916 Events enabled by this environment will no longer be sent, however
10917 event handlers currently running will continue to run. Caution must
10918 be exercised in the design of event handlers whose environment may
10919 be disposed and thus become invalid during their execution.
10920 <p/>
10921 This environment may not be used after this call.
10922 This call returns to the caller.
10923 </description>
10924 <origin>new</origin>
10925 <capabilities>
10926 </capabilities>
10927 <parameters>
10928 </parameters>
10929 <errors>
10930 </errors>
10931 </function>
10932
10933 <function id="SetEnvironmentLocalStorage" jkernel="yes" phase="any" callbacksafe="safe" impl="innative notrace" num="148">
10934 <synopsis>Set Environment Local Storage</synopsis>
10935 <description>
10936 The VM stores a pointer value associated with each environment.
10937 This pointer value is called <i>environment-local storage</i>.
10938 This value is <code>NULL</code> unless set with this function.
10939 Agents can allocate memory in which they store environment specific
10940 information. By setting environment-local storage it can then be
10941 accessed with
10942 <functionlink id="GetEnvironmentLocalStorage"></functionlink>.
10943 <p/>
10944 Called by the agent to set the value of the <jvmti/>
10945 environment-local storage. <jvmti/> supplies to the agent a pointer-size
10946 environment-local storage that can be used to record per-environment
10947 information.
10948 </description>
10949 <origin>new</origin>
10950 <capabilities>
10951 </capabilities>
10952 <parameters>
10953 <param id="data">
10954 <inbuf>
10955 <void/>
10956 <nullok>value is set to <code>NULL</code></nullok>
10957 </inbuf>
10958 <description>
10959 The value to be entered into the environment-local storage.
10960 </description>
10961 </param>
10962 </parameters>
10963 <errors>
10964 </errors>
10965 </function>
10966
10967 <function id="GetEnvironmentLocalStorage" jkernel="yes" phase="any" callbacksafe="safe" impl="innative notrace" num="147">
10968 <synopsis>Get Environment Local Storage</synopsis>
10969 <description>
10970 Called by the agent to get the value of the <jvmti/> environment-local
10971 storage.
10972 </description>
10973 <origin>new</origin>
10974 <capabilities>
10975 </capabilities>
10976 <parameters>
10977 <param id="data_ptr">
10978 <agentbuf><void/></agentbuf>
10979 <description>
10980 Pointer through which the value of the environment local
10981 storage is returned.
10982 If environment-local storage has not been set with
10983 <functionlink id="SetEnvironmentLocalStorage"></functionlink> returned
10984 pointer is <code>NULL</code>.
10985 </description>
10986 </param>
10987 </parameters>
10988 <errors>
10989 </errors>
10990 </function>
10991
10992 <function id="GetVersionNumber" jkernel="yes" phase="any" num="88">
10993 <synopsis>Get Version Number</synopsis>
10994 <description>
10995 Return the <jvmti/> version via <code>version_ptr</code>.
10996 The return value is the version identifier.
10997 The version identifier includes major, minor and micro
10998 version as well as the interface type.
10999 <constants id="jvmtiVersionInterfaceTypes" label="Version Interface Types" kind="bits">
11000 <constant id="JVMTI_VERSION_INTERFACE_JNI" num="0x00000000">
11001 Value of <code>JVMTI_VERSION_MASK_INTERFACE_TYPE</code> for JNI.
11002 </constant>
11003 <constant id="JVMTI_VERSION_INTERFACE_JVMTI" num="0x30000000">
11004 Value of <code>JVMTI_VERSION_MASK_INTERFACE_TYPE</code> for <jvmti/>.
11005 </constant>
11006 </constants>
11007 <constants id="jvmtiVersionMasks" label="Version Masks" kind="bits">
11008 <constant id="JVMTI_VERSION_MASK_INTERFACE_TYPE" num="0x70000000">
11009 Mask to extract interface type.
11010 The value of the version returned by this function masked with
11011 <code>JVMTI_VERSION_MASK_INTERFACE_TYPE</code> is always
11012 <code>JVMTI_VERSION_INTERFACE_JVMTI</code>
11013 since this is a <jvmti/> function.
11014 </constant>
11015 <constant id="JVMTI_VERSION_MASK_MAJOR" num="0x0FFF0000">
11016 Mask to extract major version number.
11017 </constant>
11018 <constant id="JVMTI_VERSION_MASK_MINOR" num="0x0000FF00">
11019 Mask to extract minor version number.
11020 </constant>
11021 <constant id="JVMTI_VERSION_MASK_MICRO" num="0x000000FF">
11022 Mask to extract micro version number.
11023 </constant>
11024 </constants>
11025 <constants id="jvmtiVersionShifts" label="Version Shifts" kind="bits">
11026 <constant id="JVMTI_VERSION_SHIFT_MAJOR" num="16">
11027 Shift to extract major version number.
11028 </constant>
11029 <constant id="JVMTI_VERSION_SHIFT_MINOR" num="8">
11030 Shift to extract minor version number.
11031 </constant>
11032 <constant id="JVMTI_VERSION_SHIFT_MICRO" num="0">
11033 Shift to extract micro version number.
11034 </constant>
11035 </constants>
11036 </description>
11037 <origin>jvmdi</origin>
11038 <capabilities>
11039 </capabilities>
11040 <parameters>
11041 <param id="version_ptr">
11042 <outptr><jint/></outptr>
11043 <description>
11044 On return, points to the <jvmti/> version.
11045 </description>
11046 </param>
11047 </parameters>
11048 <errors>
11049 </errors>
11050 </function>
11051
11052
11053 <function id="GetErrorName" phase="any" num="128">
11054 <synopsis>Get Error Name</synopsis>
11055 <description>
11056 Return the symbolic name for an
11057 <internallink id="ErrorSection">error code</internallink>.
11058 <p/>
11059 For example
11060 <code>GetErrorName(env, JVMTI_ERROR_NONE, &err_name)</code>
11061 would return in <code>err_name</code> the string
11062 <code>"JVMTI_ERROR_NONE"</code>.
11063 </description>
11064 <origin>new</origin>
11065 <capabilities>
11066 </capabilities>
11067 <parameters>
11068 <param id="error">
11069 <enum>jvmtiError</enum>
11070 <description>
11071 The error code.
11072 </description>
11073 </param>
11074 <param id="name_ptr">
11075 <allocbuf><char/></allocbuf>
11076 <description>
11077 On return, points to the error name.
11078 The name is encoded as a
11079 <internallink id="mUTF">modified UTF-8</internallink> string,
11080 but is restricted to the ASCII subset.
11081 </description>
11082 </param>
11083 </parameters>
11084 <errors>
11085 </errors>
11086 </function>
11087
11088 <function id="SetVerboseFlag" phase="any" num="150">
11089 <synopsis>Set Verbose Flag</synopsis>
11090 <description>
11091 <constants id="jvmtiVerboseFlag" label="Verbose Flag Enumeration" kind="enum">
11092 <constant id="JVMTI_VERBOSE_OTHER" num="0">
11093 Verbose output other than the below.
11094 </constant>
11095 <constant id="JVMTI_VERBOSE_GC" num="1">
11096 Verbose garbage collector output, like that specified with <code>-verbose:gc</code>.
11097 </constant>
11098 <constant id="JVMTI_VERBOSE_CLASS" num="2">
11099 Verbose class loading output, like that specified with <code>-verbose:class</code>.
11100 </constant>
11101 <constant id="JVMTI_VERBOSE_JNI" num="4">
11102 Verbose JNI output, like that specified with <code>-verbose:jni</code>.
11103 </constant>
11104 </constants>
11105 Control verbose output.
11106 This is the output which typically is sent to <code>stderr</code>.
11107 </description>
11108 <origin>new</origin>
11109 <capabilities>
11110 </capabilities>
11111 <parameters>
11112 <param id="flag">
11113 <enum>jvmtiVerboseFlag</enum>
11114 <description>
11115 Which verbose flag to set.
11116 </description>
11117 </param>
11118 <param id="value">
11119 <jboolean/>
11120 <description>
11121 New value of the flag.
11122 </description>
11123 </param>
11124 </parameters>
11125 <errors>
11126 </errors>
11127 </function>
11128
11129
11130 <function id="GetJLocationFormat" phase="any" num="129">
11131 <synopsis>Get JLocation Format</synopsis>
11132 <description>
11133 Although the greatest functionality is achieved with location information
11134 referencing the virtual machine bytecode index, the definition of
11135 <code>jlocation</code> has intentionally been left unconstrained to allow VM
11136 implementations that do not have this information.
11137 <p/>
11138 This function describes the representation of <code>jlocation</code> used in this VM.
11139 If the returned format is <datalink id="JVMTI_JLOCATION_JVMBCI"></datalink>,
11140 <code>jlocation</code>s can
11141 be used as in indices into the array returned by
11142 <functionlink id="GetBytecodes"></functionlink>.
11143 <constants id="jvmtiJlocationFormat" label="JLocation Format Enumeration" kind="enum">
11144 <constant id="JVMTI_JLOCATION_JVMBCI" num="1">
11145 <code>jlocation</code> values represent virtual machine
11146 bytecode indices--that is, offsets into the
11147 virtual machine code for a method.
11148 </constant>
11149 <constant id="JVMTI_JLOCATION_MACHINEPC" num="2">
11150 <code>jlocation</code> values represent native machine
11151 program counter values.
11152 </constant>
11153 <constant id="JVMTI_JLOCATION_OTHER" num="0">
11154 <code>jlocation</code> values have some other representation.
11155 </constant>
11156 </constants>
11157 </description>
11158 <origin>new</origin>
11159 <capabilities>
11160 </capabilities>
11161 <parameters>
11162 <param id="format_ptr">
11163 <outptr><enum>jvmtiJlocationFormat</enum></outptr>
11164 <description>
11165 On return, points to the format identifier for <code>jlocation</code> values.
11166 </description>
11167 </param>
11168 </parameters>
11169 <errors>
11170 </errors>
11171 </function>
11172
11173 </category>
11174
11175 </functionsection>
11176
11177 <errorsection label="Error Reference">
11178 <intro>
11179 Every <jvmti/> function returns a <b><code>jvmtiError</code></b> error code.
11180 <p/>
11181 It is the responsibility of the agent to call <jvmti/> functions with
11182 valid parameters and in the proper context (calling thread is attached,
11183 phase is correct, etc.).
11184 Detecting some error conditions may be difficult, inefficient, or
11185 impossible for an implementation.
11186 The errors listed in
11187 <internallink id="reqerrors">Function Specific Required Errors</internallink>
11188 must be detected by the implementation.
11189 All other errors represent the recommended response to the error
11190 condition.
11191 </intro>
11192
11193 <errorcategory id="universal-error" label="Universal Errors">
11194 <intro>
11195 The following errors may be returned by any function
11196 </intro>
11197
11198 <errorid id="JVMTI_ERROR_NONE" num="0">
11199 No error has occurred. This is the error code that is returned
11200 on successful completion of the function.
11201 </errorid>
11202 <errorid id="JVMTI_ERROR_NULL_POINTER" num="100">
11203 Pointer is unexpectedly <code>NULL</code>.
11204 </errorid>
11205 <errorid id="JVMTI_ERROR_OUT_OF_MEMORY" num="110">
11206 The function attempted to allocate memory and no more memory was
11207 available for allocation.
11208 </errorid>
11209 <errorid id="JVMTI_ERROR_ACCESS_DENIED" num="111">
11210 The desired functionality has not been enabled in this virtual machine.
11211 </errorid>
11212 <errorid id="JVMTI_ERROR_UNATTACHED_THREAD" num="115">
11213 The thread being used to call this function is not attached
11214 to the virtual machine. Calls must be made from attached threads.
11215 See <code>AttachCurrentThread</code> in the JNI invocation API.
11216 </errorid>
11217 <errorid id="JVMTI_ERROR_INVALID_ENVIRONMENT" num="116">
11218 The <jvmti/> environment provided is no longer connected or is
11219 not an environment.
11220 </errorid>
11221 <errorid id="JVMTI_ERROR_WRONG_PHASE" num="112">
11222 The desired functionality is not available in the current
11223 <functionlink id="GetPhase">phase</functionlink>.
11224 Always returned if the virtual machine has completed running.
11225 </errorid>
11226 <errorid id="JVMTI_ERROR_INTERNAL" num="113">
11227 An unexpected internal error has occurred.
11228 </errorid>
11229 </errorcategory>
11230
11231 <errorcategory id="reqerrors" label="Function Specific Required Errors">
11232 <intro>
11233 The following errors are returned by some <jvmti/> functions and must
11234 be returned by the implementation when the condition occurs.
11235 </intro>
11236
11237 <errorid id="JVMTI_ERROR_INVALID_PRIORITY" num="12">
11238 Invalid priority.
11239 </errorid>
11240 <errorid id="JVMTI_ERROR_THREAD_NOT_SUSPENDED" num="13">
11241 Thread was not suspended.
11242 </errorid>
11243 <errorid id="JVMTI_ERROR_THREAD_SUSPENDED" num="14">
11244 Thread already suspended.
11245 </errorid>
11246 <errorid id="JVMTI_ERROR_THREAD_NOT_ALIVE" num="15">
11247 This operation requires the thread to be alive--that is,
11248 it must be started and not yet have died.
11249 </errorid>
11250 <errorid id="JVMTI_ERROR_CLASS_NOT_PREPARED" num="22">
11251 The class has been loaded but not yet prepared.
11252 </errorid>
11253 <errorid id="JVMTI_ERROR_NO_MORE_FRAMES" num="31">
11254 There are no Java programming language or JNI stack frames at the specified depth.
11255 </errorid>
11256 <errorid id="JVMTI_ERROR_OPAQUE_FRAME" num="32">
11257 Information about the frame is not available (e.g. for native frames).
11258 </errorid>
11259 <errorid id="JVMTI_ERROR_DUPLICATE" num="40">
11260 Item already set.
11261 </errorid>
11262 <errorid id="JVMTI_ERROR_NOT_FOUND" num="41">
11263 Desired element (e.g. field or breakpoint) not found
11264 </errorid>
11265 <errorid id="JVMTI_ERROR_NOT_MONITOR_OWNER" num="51">
11266 This thread doesn't own the raw monitor.
11267 </errorid>
11268 <errorid id="JVMTI_ERROR_INTERRUPT" num="52">
11269 The call has been interrupted before completion.
11270 </errorid>
11271 <errorid id="JVMTI_ERROR_UNMODIFIABLE_CLASS" num="79">
11272 The class cannot be modified.
11273 </errorid>
11274 <errorid id="JVMTI_ERROR_NOT_AVAILABLE" num="98">
11275 The functionality is not available in this virtual machine.
11276 </errorid>
11277 <errorid id="JVMTI_ERROR_ABSENT_INFORMATION" num="101">
11278 The requested information is not available.
11279 </errorid>
11280 <errorid id="JVMTI_ERROR_INVALID_EVENT_TYPE" num="102">
11281 The specified event type ID is not recognized.
11282 </errorid>
11283 <errorid id="JVMTI_ERROR_NATIVE_METHOD" num="104">
11284 The requested information is not available for native method.
11285 </errorid>
11286 <errorid id="JVMTI_ERROR_CLASS_LOADER_UNSUPPORTED" num="106">
11287 The class loader does not support this operation.
11288 </errorid>
11289 </errorcategory>
11290
11291 <errorcategory id="function-specific-errors" label="Function Specific Agent Errors">
11292 <intro>
11293 The following errors are returned by some <jvmti/> functions.
11294 They are returned in the event of invalid parameters passed by the
11295 agent or usage in an invalid context.
11296 An implementation is not required to detect these errors.
11297 </intro>
11298
11299 <errorid id="JVMTI_ERROR_INVALID_THREAD" num="10">
11300 The passed thread is not a valid thread.
11301 </errorid>
11302 <errorid id="JVMTI_ERROR_INVALID_FIELDID" num="25">
11303 Invalid field.
11304 </errorid>
11305 <errorid id="JVMTI_ERROR_INVALID_METHODID" num="23">
11306 Invalid method.
11307 </errorid>
11308 <errorid id="JVMTI_ERROR_INVALID_LOCATION" num="24">
11309 Invalid location.
11310 </errorid>
11311 <errorid id="JVMTI_ERROR_INVALID_OBJECT" num="20">
11312 Invalid object.
11313 </errorid>
11314 <errorid id="JVMTI_ERROR_INVALID_CLASS" num="21">
11315 Invalid class.
11316 </errorid>
11317 <errorid id="JVMTI_ERROR_TYPE_MISMATCH" num="34">
11318 The variable is not an appropriate type for the function used.
11319 </errorid>
11320 <errorid id="JVMTI_ERROR_INVALID_SLOT" num="35">
11321 Invalid slot.
11322 </errorid>
11323 <errorid id="JVMTI_ERROR_MUST_POSSESS_CAPABILITY" num="99">
11324 The capability being used is false in this environment.
11325 </errorid>
11326 <errorid id="JVMTI_ERROR_INVALID_THREAD_GROUP" num="11">
11327 Thread group invalid.
11328 </errorid>
11329 <errorid id="JVMTI_ERROR_INVALID_MONITOR" num="50">
11330 Invalid raw monitor.
11331 </errorid>
11332 <errorid id="JVMTI_ERROR_ILLEGAL_ARGUMENT" num="103">
11333 Illegal argument.
11334 </errorid>
11335 <errorid id="JVMTI_ERROR_INVALID_TYPESTATE" num="65">
11336 The state of the thread has been modified, and is now inconsistent.
11337 </errorid>
11338 <errorid id="JVMTI_ERROR_UNSUPPORTED_VERSION" num="68">
11339 A new class file has a version number not supported by this VM.
11340 </errorid>
11341 <errorid id="JVMTI_ERROR_INVALID_CLASS_FORMAT" num="60">
11342 A new class file is malformed (the VM would return a <code>ClassFormatError</code>).
11343 </errorid>
11344 <errorid id="JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION" num="61">
11345 The new class file definitions would lead to a circular
11346 definition (the VM would return a <code>ClassCircularityError</code>).
11347 </errorid>
11348 <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED" num="63">
11349 A new class file would require adding a method.
11350 </errorid>
11351 <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED" num="64">
11352 A new class version changes a field.
11353 </errorid>
11354 <errorid id="JVMTI_ERROR_FAILS_VERIFICATION" num="62">
11355 The class bytes fail verification.
11356 </errorid>
11357 <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED" num="66">
11358 A direct superclass is different for the new class
11359 version, or the set of directly implemented
11360 interfaces is different.
11361 </errorid>
11362 <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED" num="67">
11363 A new class version does not declare a method
11364 declared in the old class version.
11365 </errorid>
11366 <errorid id="JVMTI_ERROR_NAMES_DONT_MATCH" num="69">
11367 The class name defined in the new class file is
11368 different from the name in the old class object.
11369 </errorid>
11370 <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED" num="70">
11371 A new class version has different modifiers.
11372 </errorid>
11373 <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED" num="71">
11374 A method in the new class version has different modifiers
11375 than its counterpart in the old class version.
11376 </errorid>
11377 </errorcategory>
11378 </errorsection>
11379
11380 <eventsection label="Events">
11381 <intro label="Handling Events" id="eventIntro">
11382 Agents can be informed of many events that occur in application
11383 programs.
11384 <p/>
11385 To handle events, designate a set of callback functions with
11386 <functionlink id="SetEventCallbacks"></functionlink>.
11387 For each event the corresponding callback function will be
11388 called.
11389 Arguments to the callback function provide additional
11390 information about the event.
11391 <p/>
11392 The callback function is usually called from within an application
11393 thread. The <jvmti/> implementation does not
11394 queue events in any way. This means
11395 that event callback functions must be written
11396 carefully. Here are some general guidelines. See
11397 the individual event descriptions for further
11398 suggestions.
11399 <p/>
11400 <ul>
11401 <li>Any exception thrown during the execution of an event callback can
11402 overwrite any current pending exception in the current application thread.
11403 Care must be taken to preserve a pending exception
11404 when an event callback makes a JNI call that might generate an exception.
11405 </li>
11406 <li>Event callback functions must be re-entrant. The <jvmti/> implementation does
11407 not queue events. If an agent needs to process events one at a time, it
11408 can use a raw monitor inside the
11409 event callback functions to serialize event processing.
11410 </li>
11411 <li>Event callback functions that execute JNI's FindClass function to load
11412 classes need to note that FindClass locates the class loader associated
11413 with the current native method. For the purposes of class loading, an
11414 event callback that includes a JNI environment as a parameter to the
11415 callback will treated as if it is a native call, where the native method
11416 is in the class of the event thread's current frame.
11417 </li>
11418 </ul>
11419 <p/>
11420 Some <jvmti/> events identify objects with JNI references.
11421 All references
11422 in <jvmti/> events are JNI local references and will become invalid
11423 after the event callback returns.
11424 Unless stated otherwise, memory referenced by pointers sent in event
11425 callbacks may not be referenced after the event callback returns.
11426 <p/>
11427 Except where stated otherwise, events are delivered on the thread
11428 that caused the event.
11429 Events are sent at the time they occur.
11430 The specification for each event includes the set of
11431 <functionlink id="GetPhase">phases</functionlink> in which it can be sent;
11432 if an event triggering activity occurs during another phase, no event
11433 is sent.
11434 <p/>
11435 A thread that generates an event does not change its execution status
11436 (for example, the event does not cause the thread to be suspended).
11437 If an agent wishes the event to result in suspension, then the agent
11438 is responsible for explicitly suspending the thread with
11439 <functionlink id="SuspendThread"></functionlink>.
11440 <p/>
11441 If an event is enabled in multiple environments, the event will be sent
11442 to each agent in the order that the environments were created.
11443 </intro>
11444
11445 <intro label="Enabling Events" id="enablingevents">
11446 All events are initially disabled. In order to receive any
11447 event:
11448 <ul>
11449 <li>
11450 If the event requires a capability, that capability must
11451 be added with
11452 <functionlink id="AddCapabilities"></functionlink>.
11453 </li>
11454 <li>
11455 A callback for the event must be set with
11456 <functionlink id="SetEventCallbacks"></functionlink>.
11457 </li>
11458 <li>
11459 The event must be enabled with
11460 <functionlink id="SetEventNotificationMode"></functionlink>.
11461 </li>
11462 </ul>
11463 </intro>
11464
11465 <intro label="Multiple Co-located Events" id="eventorder">
11466 In many situations it is possible for multiple events to occur
11467 at the same location in one thread. When this happens, all the events
11468 are reported through the event callbacks in the order specified in this section.
11469 <p/>
11470 If the current location is at the entry point of a method, the
11471 <eventlink id="MethodEntry"></eventlink> event is reported before
11472 any other event at the current location in the same thread.
11473 <p/>
11474 If an exception catch has been detected at the current location,
11475 either because it is the beginning of a catch clause or a native method
11476 that cleared a pending exception has returned, the
11477 <code>exceptionCatch</code> event is reported before
11478 any other event at the current location in the same thread.
11479 <p/>
11480 If a <code>singleStep</code> event or
11481 <code>breakpoint</code> event is triggered at the
11482 current location, the event is defined to occur
11483 immediately before the code at the current location is executed.
11484 These events are reported before any events which are triggered
11485 by the execution of code at the current location in the same
11486 thread (specifically:
11487 <code>exception</code>,
11488 <code>fieldAccess</code>, and
11489 <code>fieldModification</code>).
11490 If both a step and breakpoint event are triggered for the same thread and
11491 location, the step event is reported before the breakpoint event.
11492 <p/>
11493 If the current location is the exit point of a method (that is, the last
11494 location before returning to the caller), the
11495 <eventlink id="MethodExit"></eventlink> event and
11496 the <eventlink id="FramePop"></eventlink> event (if requested)
11497 are reported after all other events at the current location in the same
11498 thread. There is no specified ordering of these two events
11499 with respect to each other.
11500 <p/>
11501 Co-located events can be triggered during the processing of some other
11502 event by the agent at the same location in the same thread.
11503 If such an event, of type <i>y</i>, is triggered during the processing of
11504 an event of type <i>x</i>, and if <i>x</i>
11505 precedes <i>y</i> in the ordering specified above, the co-located event
11506 <i>y</i> is reported for the current thread and location. If <i>x</i> does not precede
11507 <i>y</i>, <i>y</i> is not reported for the current thread and location.
11508 For example, if a breakpoint is set at the current location
11509 during the processing of <eventlink id="SingleStep"></eventlink>,
11510 that breakpoint will be reported before the thread moves off the current
11511 location.
11512 <p/>The following events are never considered to be co-located with
11513 other events.
11514 <ul>
11515 <li><eventlink id="VMStart"></eventlink></li>
11516 <li><eventlink id="VMInit"></eventlink></li>
11517 <li><eventlink id="VMDeath"></eventlink></li>
11518 <li><eventlink id="ThreadStart"></eventlink></li>
11519 <li><eventlink id="ThreadEnd"></eventlink></li>
11520 <li><eventlink id="ClassLoad"></eventlink></li>
11521 <li><eventlink id="ClassPrepare"></eventlink></li>
11522 </ul>
11523 </intro>
11524
11525 <intro label="Event Callbacks" id="jvmtiEventCallbacks">
11526 The event callback structure below is used to specify the handler function
11527 for events. It is set with the
11528 <functionlink id="SetEventCallbacks"></functionlink> function.
11529 </intro>
11530
11531 <event label="Single Step"
11532 id="SingleStep" const="JVMTI_EVENT_SINGLE_STEP" filtered="thread" num="60">
11533 <description>
11534 Single step events allow the agent to trace thread execution
11535 at the finest granularity allowed by the VM. A single step event is
11536 generated whenever a thread reaches a new location.
11537 Typically, single step events represent the completion of one VM
11538 instruction as defined in <vmspec/>. However, some implementations
11539 may define locations differently. In any case the
11540 <code>method</code> and <code>location</code>
11541 parameters uniquely identify the current location and allow
11542 the mapping to source file and line number when that information is
11543 available.
11544 <p/>
11545 No single step events are generated from within native methods.
11546 </description>
11547 <origin>jvmdi</origin>
11548 <capabilities>
11549 <required id="can_generate_single_step_events"></required>
11550 </capabilities>
11551 <parameters>
11552 <param id="jni_env">
11553 <outptr>
11554 <struct>JNIEnv</struct>
11555 </outptr>
11556 <description>
11557 The JNI environment of the event (current) thread
11558 </description>
11559 </param>
11560 <param id="thread">
11561 <jthread/>
11562 <description>
11563 Thread about to execution a new instruction
11564 </description>
11565 </param>
11566 <param id="klass">
11567 <jclass method="method"/>
11568 <description>
11569 Class of the method about to execute a new instruction
11570 </description>
11571 </param>
11572 <param id="method">
11573 <jmethodID class="klass"/>
11574 <description>
11575 Method about to execute a new instruction
11576 </description>
11577 </param>
11578 <param id="location">
11579 <jlocation/>
11580 <description>
11581 Location of the new instruction
11582 </description>
11583 </param>
11584 </parameters>
11585 </event>
11586
11587 <event label="Breakpoint"
11588 id="Breakpoint" const="JVMTI_EVENT_BREAKPOINT" filtered="thread" num="62">
11589 <description>
11590 Breakpoint events are generated whenever a thread reaches a location
11591 designated as a breakpoint with <functionlink id="SetBreakpoint"></functionlink>.
11592 The <code>method</code> and <code>location</code>
11593 parameters uniquely identify the current location and allow
11594 the mapping to source file and line number when that information is
11595 available.
11596 </description>
11597 <origin>jvmdi</origin>
11598 <capabilities>
11599 <required id="can_generate_breakpoint_events"></required>
11600 </capabilities>
11601 <parameters>
11602 <param id="jni_env">
11603 <outptr>
11604 <struct>JNIEnv</struct>
11605 </outptr>
11606 <description>
11607 The JNI environment of the event (current) thread.
11608 </description>
11609 </param>
11610 <param id="thread">
11611 <jthread/>
11612 <description>
11613 Thread that hit the breakpoint
11614 </description>
11615 </param>
11616 <param id="klass">
11617 <jclass method="method"/>
11618 <description>
11619 Class of the method that hit the breakpoint
11620 </description>
11621 </param>
11622 <param id="method">
11623 <jmethodID class="klass"/>
11624 <description>
11625 Method that hit the breakpoint
11626 </description>
11627 </param>
11628 <param id="location">
11629 <jlocation/>
11630 <description>
11631 location of the breakpoint
11632 </description>
11633 </param>
11634 </parameters>
11635 </event>
11636
11637 <event label="Field Access"
11638 id="FieldAccess" const="JVMTI_EVENT_FIELD_ACCESS" filtered="thread" num="63">
11639 <description>
11640 Field access events are generated whenever a thread accesses
11641 a field that was designated as a watchpoint
11642 with <functionlink id="SetFieldAccessWatch"></functionlink>.
11643 The <code>method</code> and <code>location</code>
11644 parameters uniquely identify the current location and allow
11645 the mapping to source file and line number when that information is
11646 available.
11647 </description>
11648 <origin>jvmdi</origin>
11649 <capabilities>
11650 <required id="can_generate_field_access_events"></required>
11651 </capabilities>
11652 <parameters>
11653 <param id="jni_env">
11654 <outptr>
11655 <struct>JNIEnv</struct>
11656 </outptr>
11657 <description>
11658 The JNI environment of the event (current) thread
11659 </description>
11660 </param>
11661 <param id="thread">
11662 <jthread/>
11663 <description>
11664 Thread accessing the field
11665 </description>
11666 </param>
11667 <param id="klass">
11668 <jclass method="method"/>
11669 <description>
11670 Class of the method where the access is occurring
11671 </description>
11672 </param>
11673 <param id="method">
11674 <jmethodID class="klass"/>
11675 <description>
11676 Method where the access is occurring
11677 </description>
11678 </param>
11679 <param id="location">
11680 <jlocation/>
11681 <description>
11682 Location where the access is occurring
11683 </description>
11684 </param>
11685 <param id="field_klass">
11686 <jclass field="field"/>
11687 <description>
11688 Class of the field being accessed
11689 </description>
11690 </param>
11691 <param id="object">
11692 <jobject/>
11693 <description>
11694 Object with the field being accessed if the field is an
11695 instance field; <code>NULL</code> otherwise
11696 </description>
11697 </param>
11698 <param id="field">
11699 <jfieldID class="field_klass"/>
11700 <description>
11701 Field being accessed
11702 </description>
11703 </param>
11704 </parameters>
11705 </event>
11706
11707 <event label="Field Modification"
11708 id="FieldModification" const="JVMTI_EVENT_FIELD_MODIFICATION" filtered="thread" num="64">
11709 <description>
11710 Field modification events are generated whenever a thread modifies
11711 a field that was designated as a watchpoint
11712 with <functionlink id="SetFieldModificationWatch"></functionlink>.
11713 The <code>method</code> and <code>location</code>
11714 parameters uniquely identify the current location and allow
11715 the mapping to source file and line number when that information is
11716 available.
11717 </description>
11718 <origin>jvmdi</origin>
11719 <capabilities>
11720 <required id="can_generate_field_modification_events"></required>
11721 </capabilities>
11722 <parameters>
11723 <param id="jni_env">
11724 <outptr>
11725 <struct>JNIEnv</struct>
11726 </outptr>
11727 <description>
11728 The JNI environment of the event (current) thread
11729 </description>
11730 </param>
11731 <param id="thread">
11732 <jthread/>
11733 <description>
11734 Thread modifying the field
11735 </description>
11736 </param>
11737 <param id="klass">
11738 <jclass method="method"/>
11739 <description>
11740 Class of the method where the modification is occurring
11741 </description>
11742 </param>
11743 <param id="method">
11744 <jmethodID class="klass"/>
11745 <description>
11746 Method where the modification is occurring
11747 </description>
11748 </param>
11749 <param id="location">
11750 <jlocation/>
11751 <description>
11752 Location where the modification is occurring
11753 </description>
11754 </param>
11755 <param id="field_klass">
11756 <jclass field="field"/>
11757 <description>
11758 Class of the field being modified
11759 </description>
11760 </param>
11761 <param id="object">
11762 <jobject/>
11763 <description>
11764 Object with the field being modified if the field is an
11765 instance field; <code>NULL</code> otherwise
11766 </description>
11767 </param>
11768 <param id="field">
11769 <jfieldID class="field_klass"/>
11770 <description>
11771 Field being modified
11772 </description>
11773 </param>
11774 <param id="signature_type">
11775 <char/>
11776 <description>
11777 Signature type of the new value
11778 </description>
11779 </param>
11780 <param id="new_value">
11781 <jvalue/>
11782 <description>
11783 The new value
11784 </description>
11785 </param>
11786 </parameters>
11787 </event>
11788
11789 <event label="Frame Pop"
11790 id="FramePop" const="JVMTI_EVENT_FRAME_POP" filtered="thread" num="61">
11791 <description>
11792 Frame pop events are generated upon exit from a single method
11793 in a single frame as specified
11794 in a call to <functionlink id="NotifyFramePop"></functionlink>.
11795 This is true whether termination is caused by
11796 executing its return instruction
11797 or by throwing an exception to its caller
11798 (see <paramlink id="was_popped_by_exception"></paramlink>).
11799 However, frame pops caused by the <functionlink id="PopFrame"/>
11800 function are not reported.
11801 <p/>
11802 The location reported by <functionlink id="GetFrameLocation"></functionlink>
11803 identifies the executable location in the returning method,
11804 immediately prior to the return.
11805 </description>
11806 <origin>jvmdi</origin>
11807 <capabilities>
11808 <required id="can_generate_frame_pop_events"></required>
11809 </capabilities>
11810 <parameters>
11811 <param id="jni_env">
11812 <outptr>
11813 <struct>JNIEnv</struct>
11814 </outptr>
11815 <description>
11816 The JNI environment of the event (current) thread
11817 </description>
11818 </param>
11819 <param id="thread">
11820 <jthread/>
11821 <description>
11822 Thread that is popping the frame
11823 </description>
11824 </param>
11825 <param id="klass">
11826 <jclass method="method"/>
11827 <description>
11828 Class of the method being popped
11829 </description>
11830 </param>
11831 <param id="method">
11832 <jmethodID class="klass"/>
11833 <description>
11834 Method being popped
11835 </description>
11836 </param>
11837 <param id="was_popped_by_exception">
11838 <jboolean/>
11839 <description>
11840 True if frame was popped by a thrown exception.
11841 False if method exited through its return instruction.
11842 </description>
11843 </param>
11844 </parameters>
11845 </event>
11846
11847 <event label="Method Entry"
11848 id="MethodEntry" const="JVMTI_EVENT_METHOD_ENTRY" filtered="thread" num="65">
11849 <description>
11850 Method entry events are generated upon entry of Java
11851 programming language methods (including native methods).
11852 <p/>
11853 The location reported by <functionlink id="GetFrameLocation"></functionlink>
11854 identifies the initial executable location in
11855 the method.
11856 <p/>
11857 Enabling method
11858 entry or exit events will significantly degrade performance on many platforms and is thus
11859 not advised for performance critical usage (such as profiling).
11860 <internallink id="bci">Bytecode instrumentation</internallink> should be
11861 used in these cases.
11862 </description>
11863 <origin>jvmdi</origin>
11864 <capabilities>
11865 <required id="can_generate_method_entry_events"></required>
11866 </capabilities>
11867 <parameters>
11868 <param id="jni_env">
11869 <outptr>
11870 <struct>JNIEnv</struct>
11871 </outptr>
11872 <description>
11873 The JNI environment of the event (current) thread
11874 </description>
11875 </param>
11876 <param id="thread">
11877 <jthread/>
11878 <description>
11879 Thread entering the method
11880 </description>
11881 </param>
11882 <param id="klass">
11883 <jclass method="method"/>
11884 <description>
11885 Class of the method being entered
11886 </description>
11887 </param>
11888 <param id="method">
11889 <jmethodID class="klass"/>
11890 <description>
11891 Method being entered
11892 </description>
11893 </param>
11894 </parameters>
11895 </event>
11896
11897 <event label="Method Exit"
11898 id="MethodExit" const="JVMTI_EVENT_METHOD_EXIT" filtered="thread" num="66">
11899 <description>
11900 Method exit events are generated upon exit from Java
11901 programming language methods (including native methods).
11902 This is true whether termination is caused by
11903 executing its return instruction
11904 or by throwing an exception to its caller
11905 (see <paramlink id="was_popped_by_exception"></paramlink>).
11906 <p/>
11907 The <code>method</code> field uniquely identifies the
11908 method being entered or exited. The <code>frame</code> field provides
11909 access to the stack frame for the method.
11910 <p/>
11911 The location reported by <functionlink id="GetFrameLocation"></functionlink>
11912 identifies the executable location in the returning method
11913 immediately prior to the return.
11914 <p/>
11915 Enabling method
11916 entry or exit events will significantly degrade performance on many platforms and is thus
11917 not advised for performance critical usage (such as profiling).
11918 <internallink id="bci">Bytecode instrumentation</internallink> should be
11919 used in these cases.
11920 </description>
11921 <origin>jvmdi</origin>
11922 <capabilities>
11923 <required id="can_generate_method_exit_events"></required>
11924 </capabilities>
11925 <parameters>
11926 <param id="jni_env">
11927 <outptr>
11928 <struct>JNIEnv</struct>
11929 </outptr>
11930 <description>
11931 The JNI environment of the event (current) thread
11932 </description>
11933 </param>
11934 <param id="thread">
11935 <jthread/>
11936 <description>
11937 Thread exiting the method
11938 </description>
11939 </param>
11940 <param id="klass">
11941 <jclass method="method"/>
11942 <description>
11943 Class of the method being exited
11944 </description>
11945 </param>
11946 <param id="method">
11947 <jmethodID class="klass"/>
11948 <description>
11949 Method being exited
11950 </description>
11951 </param>
11952 <param id="was_popped_by_exception">
11953 <jboolean/>
11954 <description>
11955 True if frame was popped by a thrown exception.
11956 False if method exited through its return instruction.
11957 </description>
11958 </param>
11959 <param id="return_value">
11960 <jvalue/>
11961 <description>
11962 The return value of the method being exited.
11963 Undefined and should not be used if
11964 <paramlink id="was_popped_by_exception"></paramlink>
11965 is true.
11966 </description>
11967 </param>
11968 </parameters>
11969 </event>
11970
11971 <event label="Native Method Bind" phase="any"
11972 id="NativeMethodBind" const="JVMTI_EVENT_NATIVE_METHOD_BIND" num="67">
11973 <description>
11974 A Native Method Bind event is sent when a VM binds a
11975 Java programming language native method
11976 to the address of a function that implements the native method.
11977 This will occur when the native method is called for the first time
11978 and also occurs when the JNI function <code>RegisterNatives</code> is called.
11979 This event allows the bind to be redirected to an agent-specified
11980 proxy function.
11981 This event is not sent when the native method is unbound.
11982 Typically, this proxy function will need to be specific to a
11983 particular method or, to handle the general case, automatically
11984 generated assembly code, since after instrumentation code is
11985 executed the function at the original binding
11986 address will usually be invoked.
11987 The original binding can be restored or the redirection changed
11988 by use of the JNI function <code>RegisterNatives</code>.
11989 Some events may be sent during the primordial phase, JNI and
11990 most of <jvmti/> cannot be used at this time but the method and
11991 address can be saved for use later.
11992 </description>
11993 <origin>new</origin>
11994 <capabilities>
11995 <required id="can_generate_native_method_bind_events"></required>
11996 </capabilities>
11997 <parameters>
11998 <param id="jni_env">
11999 <outptr>
12000 <struct>JNIEnv</struct>
12001 </outptr>
12002 <description>
12003 The JNI environment of the event (current) thread
12004 Will be <code>NULL</code> if sent during the primordial
12005 <functionlink id="GetPhase">phase</functionlink>.
12006 </description>
12007 </param>
12008 <param id="thread">
12009 <jthread/>
12010 <description>
12011 Thread requesting the bind
12012 </description>
12013 </param>
12014 <param id="klass">
12015 <jclass method="method"/>
12016 <description>
12017 Class of the method being bound
12018 </description>
12019 </param>
12020 <param id="method">
12021 <jmethodID class="klass"/>
12022 <description>
12023 Native method being bound
12024 </description>
12025 </param>
12026 <param id="address">
12027 <outptr><void/></outptr>
12028 <description>
12029 The address the VM is about to bind to--that is, the
12030 address of the implementation of the native method
12031 </description>
12032 </param>
12033 <param id="new_address_ptr">
12034 <agentbuf><void/></agentbuf>
12035 <description>
12036 if the referenced address is changed (that is, if
12037 <code>*new_address_ptr</code> is set), the binding
12038 will instead be made to the supplied address.
12039 </description>
12040 </param>
12041 </parameters>
12042 </event>
12043
12044 <event label="Exception"
12045 id="Exception" const="JVMTI_EVENT_EXCEPTION" filtered="thread" num="58">
12046 <description>
12047 Exception events are generated whenever an exception is first detected
12048 in a Java programming language method.
12049 Where "exception" means any <code>java.lang.Throwable</code>.
12050 The exception may have been thrown by a Java programming language or native
12051 method, but in the case of native methods, the event is not generated
12052 until the exception is first seen by a Java programming language method. If an exception is
12053 set and cleared in a native method (and thus is never visible to Java programming language code),
12054 no exception event is generated.
12055 <p/>
12056 The <code>method</code> and <code>location</code>
12057 parameters uniquely identify the current location
12058 (where the exception was detected) and allow
12059 the mapping to source file and line number when that information is
12060 available. The <code>exception</code> field identifies the thrown
12061 exception object. The <code>catch_method</code>
12062 and <code>catch_location</code> identify the location of the catch clause,
12063 if any, that handles the thrown exception. If there is no such catch clause,
12064 each field is set to 0. There is no guarantee that the thread will ever
12065 reach this catch clause. If there are native methods on the call stack
12066 between the throw location and the catch clause, the exception may
12067 be reset by one of those native methods.
12068 Similarly, exceptions that are reported as uncaught (<code>catch_klass</code>
12069 et al. set to 0) may in fact be caught by native code.
12070 Agents can check for these occurrences by monitoring
12071 <eventlink id="ExceptionCatch"></eventlink> events.
12072 Note that finally clauses are implemented as catch and re-throw. Therefore they
12073 will be reported in the catch location.
12074 </description>
12075 <origin>jvmdi</origin>
12076 <capabilities>
12077 <required id="can_generate_exception_events"></required>
12078 </capabilities>
12079 <parameters>
12080 <param id="jni_env">
12081 <outptr>
12082 <struct>JNIEnv</struct>
12083 </outptr>
12084 <description>
12085 The JNI environment of the event (current) thread
12086 </description>
12087 </param>
12088 <param id="thread">
12089 <jthread/>
12090 <description>
12091 Thread generating the exception
12092 </description>
12093 </param>
12094 <param id="klass">
12095 <jclass method="method"/>
12096 <description>
12097 Class generating the exception
12098 </description>
12099 </param>
12100 <param id="method">
12101 <jmethodID class="klass"/>
12102 <description>
12103 Method generating the exception
12104 </description>
12105 </param>
12106 <param id="location">
12107 <jlocation/>
12108 <description>
12109 Location where exception occurred
12110 </description>
12111 </param>
12112 <param id="exception">
12113 <jobject/>
12114 <description>
12115 The exception being thrown
12116 </description>
12117 </param>
12118 <param id="catch_klass">
12119 <jclass method="catch_method"/>
12120 <description>
12121 Class that will catch the exception, or <code>NULL</code> if no known catch
12122 </description>
12123 </param>
12124 <param id="catch_method">
12125 <jmethodID class="catch_klass"/>
12126 <description>
12127 Method that will catch the exception, or <code>NULL</code> if no known catch
12128 </description>
12129 </param>
12130 <param id="catch_location">
12131 <jlocation/>
12132 <description>
12133 location which will catch the exception or zero if no known catch
12134 </description>
12135 </param>
12136 </parameters>
12137 </event>
12138
12139 <event label="Exception Catch"
12140 id="ExceptionCatch" const="JVMTI_EVENT_EXCEPTION_CATCH" filtered="thread" num="59">
12141 <description>
12142 Exception catch events are generated whenever a thrown exception is caught.
12143 Where "exception" means any <code>java.lang.Throwable</code>.
12144 If the exception is caught in a Java programming language method, the event is generated
12145 when the catch clause is reached. If the exception is caught in a native
12146 method, the event is generated as soon as control is returned to a Java programming language
12147 method. Exception catch events are generated for any exception for which
12148 a throw was detected in a Java programming language method.
12149 Note that finally clauses are implemented as catch and re-throw. Therefore they
12150 will generate exception catch events.
12151 <p/>
12152 The <code>method</code> and <code>location</code>
12153 parameters uniquely identify the current location
12154 and allow the mapping to source file and line number when that information is
12155 available. For exceptions caught in a Java programming language method, the
12156 <code>exception</code> object identifies the exception object. Exceptions
12157 caught in native methods are not necessarily available by the time the
12158 exception catch is reported, so the <code>exception</code> field is set
12159 to <code>NULL</code>.
12160 </description>
12161 <origin>jvmdi</origin>
12162 <capabilities>
12163 <required id="can_generate_exception_events"></required>
12164 </capabilities>
12165 <parameters>
12166 <param id="jni_env">
12167 <outptr>
12168 <struct>JNIEnv</struct>
12169 </outptr>
12170 <description>
12171 The JNI environment of the event (current) thread
12172 </description>
12173 </param>
12174 <param id="thread">
12175 <jthread/>
12176 <description>
12177 Thread catching the exception
12178 </description>
12179 </param>
12180 <param id="klass">
12181 <jclass method="method"/>
12182 <description>
12183 Class catching the exception
12184 </description>
12185 </param>
12186 <param id="method">
12187 <jmethodID class="klass"/>
12188 <description>
12189 Method catching the exception
12190 </description>
12191 </param>
12192 <param id="location">
12193 <jlocation/>
12194 <description>
12195 Location where exception is being caught
12196 </description>
12197 </param>
12198 <param id="exception">
12199 <jobject/>
12200 <description>
12201 Exception being caught
12202 </description>
12203 </param>
12204 </parameters>
12205 </event>
12206
12207 <event label="Thread Start"
12208 id="ThreadStart" const="JVMTI_EVENT_THREAD_START" num="52" phase="start">
12209 <description>
12210 Thread start events are generated by a new thread before its initial
12211 method executes.
12212 <p/>
12213 A thread may be listed in the array returned by
12214 <functionlink id="GetAllThreads"></functionlink>
12215 before its thread start event is generated.
12216 It is possible for other events to be generated
12217 on a thread before its thread start event.
12218 <p/>
12219 The event is sent on the newly started <paramlink id="thread"></paramlink>.
12220 </description>
12221 <origin>jvmdi</origin>
12222 <capabilities>
12223 </capabilities>
12224 <parameters>
12225 <param id="jni_env">
12226 <outptr>
12227 <struct>JNIEnv</struct>
12228 </outptr>
12229 <description>
12230 The JNI environment of the event (current) thread.
12231 </description>
12232 </param>
12233 <param id="thread">
12234 <jthread/>
12235 <description>
12236 Thread starting
12237 </description>
12238 </param>
12239 </parameters>
12240 </event>
12241
12242 <event label="Thread End"
12243 id="ThreadEnd" const="JVMTI_EVENT_THREAD_END" filtered="thread" num="53" phase="start">
12244 <description>
12245 Thread end events are generated by a terminating thread
12246 after its initial method has finished execution.
12247 <p/>
12248 A thread may be listed in the array returned by
12249 <functionlink id="GetAllThreads"></functionlink>
12250 after its thread end event is generated.
12251 No events are generated on a thread
12252 after its thread end event.
12253 <p/>
12254 The event is sent on the dying <paramlink id="thread"></paramlink>.
12255 </description>
12256 <origin>jvmdi</origin>
12257 <capabilities>
12258 </capabilities>
12259 <parameters>
12260 <param id="jni_env">
12261 <outptr>
12262 <struct>JNIEnv</struct>
12263 </outptr>
12264 <description>
12265 The JNI environment of the event (current) thread.
12266 </description>
12267 </param>
12268 <param id="thread">
12269 <jthread/>
12270 <description>
12271 Thread ending
12272 </description>
12273 </param>
12274 </parameters>
12275 </event>
12276
12277 <event label="Class Load"
12278 id="ClassLoad" const="JVMTI_EVENT_CLASS_LOAD" filtered="thread" phase="start" num="55">
12279 <description>
12280 A class load event is generated when a class is first loaded. The order
12281 of class load events generated by a particular thread are guaranteed
12282 to match the order of class loading within that thread.
12283 Array class creation does not generate a class load event.
12284 The creation of a primitive class (for example, java.lang.Integer.TYPE)
12285 does not generate a class load event.
12286 <p/>
12287 This event is sent at an early stage in loading the class. As
12288 a result the class should be used carefully. Note, for example,
12289 that methods and fields are not yet loaded, so queries for methods,
12290 fields, subclasses, and so on will not give correct results.
12291 See "Loading of Classes and Interfaces" in the <i>Java Language
12292 Specification</i>. For most
12293 purposes the <eventlink id="ClassPrepare"></eventlink> event will
12294 be more useful.
12295 </description>
12296 <origin>jvmdi</origin>
12297 <capabilities>
12298 </capabilities>
12299 <parameters>
12300 <param id="jni_env">
12301 <outptr>
12302 <struct>JNIEnv</struct>
12303 </outptr>
12304 <description>
12305 The JNI environment of the event (current) thread
12306 </description>
12307 </param>
12308 <param id="thread">
12309 <jthread/>
12310 <description>
12311 Thread loading the class
12312 </description>
12313 </param>
12314 <param id="klass">
12315 <jclass/>
12316 <description>
12317 Class being loaded
12318 </description>
12319 </param>
12320 </parameters>
12321 </event>
12322
12323 <elide>
12324 <event label="Class Unload"
12325 id="ClassUnload" const="JVMTI_EVENT_CLASS_UNLOAD" num="57">
12326 <description>
12327 A class unload event is generated when the class is about to be unloaded.
12328 Class unload events take place during garbage collection and must be
12329 handled extremely carefully. The garbage collector holds many locks
12330 and has suspended all other threads, so the event handler cannot depend
12331 on the ability to acquire any locks. The class unload event handler should
12332 do as little as possible, perhaps by queuing information to be processed
12333 later. In particular, the <code>jclass</code> should be used only in
12334 the JNI function <code>isSameObject</code> or in the following <jvmti/> functions:
12335 <ul>
12336 <li><functionlink id="GetClassSignature"></functionlink></li>
12337 <li><functionlink id="GetSourceFileName"></functionlink></li>
12338 <li><functionlink id="IsInterface"></functionlink></li>
12339 <li><functionlink id="IsArrayClass"></functionlink></li>
12340 </ul>
12341 </description>
12342 <origin>jvmdi</origin>
12343 <capabilities>
12344 </capabilities>
12345 <parameters>
12346 <param id="jni_env">
12347 <outptr>
12348 <struct>JNIEnv</struct>
12349 </outptr>
12350 <description>
12351 The JNI environment of the event (current) thread
12352 </description>
12353 </param>
12354 <param id="thread">
12355 <jthread/>
12356 <description>
12357 Thread generating the class unload
12358 </description>
12359 </param>
12360 <param id="klass">
12361 <jclass/>
12362 <description>
12363 Class being unloaded
12364 </description>
12365 </param>
12366 </parameters>
12367 </event>
12368 </elide>
12369
12370 <event label="Class Prepare"
12371 id="ClassPrepare" const="JVMTI_EVENT_CLASS_PREPARE" filtered="thread" phase="start" num="56">
12372 <description>
12373 A class prepare event is generated when class preparation is complete.
12374 At this point, class fields, methods, and implemented interfaces are
12375 available, and no code from the class has been executed. Since array
12376 classes never have fields or methods, class prepare events are not
12377 generated for them. Class prepare events are not generated for
12378 primitive classes (for example, <code>java.lang.Integer.TYPE</code>).
12379 </description>
12380 <origin>jvmdi</origin>
12381 <capabilities>
12382 </capabilities>
12383 <parameters>
12384 <param id="jni_env">
12385 <outptr>
12386 <struct>JNIEnv</struct>
12387 </outptr>
12388 <description>
12389 The JNI environment of the event (current) thread
12390 </description>
12391 </param>
12392 <param id="thread">
12393 <jthread/>
12394 <description>
12395 Thread generating the class prepare
12396 </description>
12397 </param>
12398 <param id="klass">
12399 <jclass/>
12400 <description>
12401 Class being prepared
12402 </description>
12403 </param>
12404 </parameters>
12405 </event>
12406
12407 <event label="Class File Load Hook" phase="start"
12408 id="ClassFileLoadHook" const="JVMTI_EVENT_CLASS_FILE_LOAD_HOOK" num="54">
12409 <description>
12410 This event is sent when the VM obtains class file data,
12411 but before it constructs
12412 the in-memory representation for that class.
12413 This event is also sent when the class is being modified by the
12414 <functionlink id="RetransformClasses"/> function or
12415 the <functionlink id="RedefineClasses"/> function,
12416 called in any <jvmti/> environment.
12417 The agent can instrument
12418 the existing class file data sent by the VM to include profiling/debugging hooks.
12419 See the description of
12420 <internallink id="bci">bytecode instrumentation</internallink>
12421 for usage information.
12422 <p/>
12423 This event may be sent before the VM is initialized (the start
12424 <functionlink id="GetPhase">phase</functionlink>).
12425 Some classes might not be compatible
12426 with the function (eg. ROMized classes) and this event will not be
12427 generated for these classes.
12428 <p/>
12429 The agent must allocate the space for the modified
12430 class file data buffer
12431 using the memory allocation function
12432 <functionlink id="Allocate"></functionlink> because the
12433 VM is responsible for freeing the new class file data buffer
12434 using <functionlink id="Deallocate"></functionlink>.
12435 <p/>
12436 If the agent wishes to modify the class file, it must set
12437 <code>new_class_data</code> to point
12438 to the newly instrumented class file data buffer and set
12439 <code>new_class_data_len</code> to the length of that
12440 buffer before returning
12441 from this call. If no modification is desired, the agent simply
12442 does not set <code>new_class_data</code>. If multiple agents
12443 have enabled this event the results are chained. That is, if
12444 <code>new_class_data</code> has been set, it becomes the
12445 <code>class_data</code> for the next agent.
12446 <p/>
12447 The order that this event is sent to each environment differs
12448 from other events.
12449 This event is sent to environments in the following order:
12450 <ul>
12451 <li><fieldlink id="can_retransform_classes"
12452 struct="jvmtiCapabilities">retransformation
12453 incapable</fieldlink>
12454 environments, in the
12455 order in which they were created
12456 </li>
12457 <li><fieldlink id="can_retransform_classes"
12458 struct="jvmtiCapabilities">retransformation
12459 capable</fieldlink>
12460 environments, in the
12461 order in which they were created
12462 </li>
12463 </ul>
12464 When triggered by <functionlink id="RetransformClasses"/>,
12465 this event is sent only to <fieldlink id="can_retransform_classes"
12466 struct="jvmtiCapabilities">retransformation
12467 capable</fieldlink>
12468 environments.
12469 </description>
12470 <origin>jvmpi</origin>
12471 <capabilities>
12472 <capability id="can_generate_all_class_hook_events"></capability>
12473 </capabilities>
12474 <parameters>
12475 <param id="jni_env">
12476 <outptr>
12477 <struct>JNIEnv</struct>
12478 </outptr>
12479 <description>
12480 The JNI environment of the event (current) thread.
12481 </description>
12482 </param>
12483 <param id="class_being_redefined">
12484 <jclass/>
12485 <description>
12486 The class being
12487 <functionlink id="RedefineClasses">redefined</functionlink> or
12488 <functionlink id="RetransformClasses">retransformed</functionlink>.
12489 <code>NULL</code> if sent by class load.
12490 </description>
12491 </param>
12492 <param id="loader">
12493 <jobject/>
12494 <description>
12495 The class loader loading the class.
12496 <code>NULL</code> if the bootstrap class loader.
12497 </description>
12498 </param>
12499 <param id="name">
12500 <vmbuf><char/></vmbuf>
12501 <description>
12502 Name of class being loaded as a VM internal qualified name
12503 (for example, "java/util/List"), encoded as a
12504 <internallink id="mUTF">modified UTF-8</internallink> string.
12505 Note: if the class is defined with a <code>NULL</code> name or
12506 without a name specified, <code>name</code> will be <code>NULL</code>.
12507 </description>
12508 </param>
12509 <param id="protection_domain">
12510 <jobject/>
12511 <description>
12512 The <code>ProtectionDomain</code> of the class.
12513 </description>
12514 </param>
12515 <param id="class_data_len">
12516 <jint/>
12517 <description>
12518 Length of current class file data buffer.
12519 </description>
12520 </param>
12521 <param id="class_data">
12522 <vmbuf><uchar/></vmbuf>
12523 <description>
12524 Pointer to the current class file data buffer.
12525 </description>
12526 </param>
12527 <param id="new_class_data_len">
12528 <outptr><jint/></outptr>
12529 <description>
12530 Pointer to the length of the new class file data buffer.
12531 </description>
12532 </param>
12533 <param id="new_class_data">
12534 <agentbuf incount="new_class_data_len"><uchar/></agentbuf>
12535 <description>
12536 Pointer to the pointer to the instrumented class file data buffer.
12537 </description>
12538 </param>
12539 </parameters>
12540 </event>
12541
12542 <event label="VM Start Event"
12543 id="VMStart" const="JVMTI_EVENT_VM_START" num="57" phase="start">
12544 <description>
12545 The VM initialization event signals the start of the VM.
12546 At this time JNI is live but the VM is not yet fully initialized.
12547 Once this event is generated, the agent is free to call any JNI function.
12548 This event signals the beginning of the start phase,
12549 <jvmti/> functions permitted in the start phase may be called.
12550 <p/>
12551 The timing of this event may depend on whether the agent has added the
12552 <internallink id="jvmtiCapabilities.can_generate_early_vmstart">
12553 <code>can_generate_early_vmstart</code></internallink> capability or not.
12554 If the capability has been added then the VM posts the event as early
12555 as possible. The VM is capable of executing bytecode but it may not have
12556 initialized to the point where it can load classes in modules other than
12557 <code>java.base</code>. Agents that do load-time instrumentation in this
12558 phase must take great care when instrumenting code that potentially
12559 executes in this phase. Care should also be taken with JNI
12560 <code>FindClass</code> as it may not be possible to load classes that are
12561 not in the <code>java.base</code> module.
12562 If the capability has not been added then the VM delays posting this
12563 event until it is capable of loading classes in modules other than
12564 <code>java.base</code> or the VM has completed its initialization.
12565 Agents that create more than one JVM TI environment, where the
12566 capability is added to some but not all environments, may observe the
12567 start phase beginning earlier in the JVM TI environments that possess
12568 the capabilty.
12569 <p/>
12570 In the case of VM start-up failure, this event will not be sent.
12571 </description>
12572 <origin>jvmdi</origin>
12573 <capabilities>
12574 </capabilities>
12575 <parameters>
12576 <param id="jni_env">
12577 <outptr>
12578 <struct>JNIEnv</struct>
12579 </outptr>
12580 <description>
12581 The JNI environment of the event (current) thread.
12582 </description>
12583 </param>
12584 </parameters>
12585 </event>
12586
12587 <event label="VM Initialization Event"
12588 id="VMInit" const="JVMTI_EVENT_VM_INIT" num="50">
12589 <description>
12590 The VM initialization event signals the completion of VM initialization. Once
12591 this event is generated, the agent is free to call any JNI or <jvmti/>
12592 function. The VM initialization event can be preceded by or can be concurrent
12593 with other events, but
12594 the preceding events should be handled carefully, if at all, because the
12595 VM has not completed its initialization. The thread start event for the
12596 main application thread is guaranteed not to occur until after the
12597 handler for the VM initialization event returns.
12598 <p/>
12599 In the case of VM start-up failure, this event will not be sent.
12600 </description>
12601 <origin>jvmdi</origin>
12602 <capabilities>
12603 </capabilities>
12604 <parameters>
12605 <param id="jni_env">
12606 <outptr>
12607 <struct>JNIEnv</struct>
12608 </outptr>
12609 <description>
12610 The JNI environment of the event (current) thread.
12611 </description>
12612 </param>
12613 <param id="thread">
12614 <jthread/>
12615 <description>
12616 The initial thread
12617 </description>
12618 </param>
12619 </parameters>
12620 </event>
12621
12622 <event label="VM Death Event"
12623 id="VMDeath" const="JVMTI_EVENT_VM_DEATH" num="51">
12624 <description>
12625 The VM death event notifies the agent of the termination of the VM.
12626 No events will occur after the VMDeath event.
12627 <p/>
12628 In the case of VM start-up failure, this event will not be sent.
12629 Note that <internallink id="onunload">Agent_OnUnload</internallink>
12630 will still be called in these cases.
12631 </description>
12632 <origin>jvmdi</origin>
12633 <capabilities>
12634 </capabilities>
12635 <parameters>
12636 <param id="jni_env">
12637 <outptr>
12638 <struct>JNIEnv</struct>
12639 </outptr>
12640 <description>
12641 The JNI environment of the event (current) thread
12642 </description>
12643 </param>
12644 </parameters>
12645 </event>
12646
12647 <event label="Compiled Method Load" phase="start"
12648 id="CompiledMethodLoad" const="JVMTI_EVENT_COMPILED_METHOD_LOAD" num="68">
12649 <description>
12650 Sent when a method is compiled and loaded into memory by the VM.
12651 If it is unloaded, the <eventlink id="CompiledMethodUnload"/> event is sent.
12652 If it is moved, the <eventlink id="CompiledMethodUnload"/> event is sent,
12653 followed by a new <code>CompiledMethodLoad</code> event.
12654 Note that a single method may have multiple compiled forms, and that
12655 this event will be sent for each form.
12656 Note also that several methods may be inlined into a single
12657 address range, and that this event will be sent for each method.
12658 <p/>
12659 These events can be sent after their initial occurrence with
12660 <functionlink id="GenerateEvents"></functionlink>.
12661 </description>
12662 <origin>jvmpi</origin>
12663 <typedef id="jvmtiAddrLocationMap" label="Native address to location entry">
12664 <field id="start_address">
12665 <vmbuf><void/></vmbuf>
12666 <description>
12667 Starting native address of code corresponding to a location
12668 </description>
12669 </field>
12670 <field id="location">
12671 <jlocation/>
12672 <description>
12673 Corresponding location. See
12674 <functionlink id="GetJLocationFormat"></functionlink>
12675 for the meaning of location.
12676 </description>
12677 </field>
12678 </typedef>
12679 <capabilities>
12680 <required id="can_generate_compiled_method_load_events"></required>
12681 </capabilities>
12682 <parameters>
12683 <param id="klass">
12684 <jclass method="method"/>
12685 <description>
12686 Class of the method being compiled and loaded
12687 </description>
12688 </param>
12689 <param id="method">
12690 <jmethodID class="klass"/>
12691 <description>
12692 Method being compiled and loaded
12693 </description>
12694 </param>
12695 <param id="code_size">
12696 <jint/>
12697 <description>
12698 Size of compiled code
12699 </description>
12700 </param>
12701 <param id="code_addr">
12702 <vmbuf><void/></vmbuf>
12703 <description>
12704 Address where compiled method code is loaded
12705 </description>
12706 </param>
12707 <param id="map_length">
12708 <jint/>
12709 <description>
12710 Number of <typelink id="jvmtiAddrLocationMap"></typelink>
12711 entries in the address map.
12712 Zero if mapping information cannot be supplied.
12713 </description>
12714 </param>
12715 <param id="map">
12716 <vmbuf><struct>jvmtiAddrLocationMap</struct></vmbuf>
12717 <description>
12718 Map from native addresses to location.
12719 The native address range of each entry is from
12720 <fieldlink id="start_address" struct="jvmtiAddrLocationMap"></fieldlink>
12721 to <code>start_address-1</code> of the next entry.
12722 <code>NULL</code> if mapping information cannot be supplied.
12723 </description>
12724 </param>
12725 <param id="compile_info">
12726 <vmbuf><void/></vmbuf>
12727 <description>
12728 VM-specific compilation information.
12729 The referenced compile information is managed by the VM
12730 and must not depend on the agent for collection.
12731 A VM implementation defines the content and lifetime
12732 of the information.
12733 </description>
12734 </param>
12735 </parameters>
12736 </event>
12737
12738 <event label="Compiled Method Unload" phase="start"
12739 id="CompiledMethodUnload" const="JVMTI_EVENT_COMPILED_METHOD_UNLOAD" num="69">
12740 <description>
12741 Sent when a compiled method is unloaded from memory.
12742 This event might not be sent on the thread which performed the unload.
12743 This event may be sent sometime after the unload occurs, but
12744 will be sent before the memory is reused
12745 by a newly generated compiled method. This event may be sent after
12746 the class is unloaded.
12747 </description>
12748 <origin>jvmpi</origin>
12749 <capabilities>
12750 <required id="can_generate_compiled_method_load_events"></required>
12751 </capabilities>
12752 <parameters>
12753 <param id="klass">
12754 <jclass method="method"/>
12755 <description>
12756 Class of the compiled method being unloaded.
12757 </description>
12758 </param>
12759 <param id="method">
12760 <jmethodID class="klass"/>
12761 <description>
12762 Compiled method being unloaded.
12763 For identification of the compiled method only -- the class
12764 may be unloaded and therefore the method should not be used
12765 as an argument to further JNI or <jvmti/> functions.
12766 </description>
12767 </param>
12768 <param id="code_addr">
12769 <vmbuf><void/></vmbuf>
12770 <description>
12771 Address where compiled method code was loaded.
12772 For identification of the compiled method only --
12773 the space may have been reclaimed.
12774 </description>
12775 </param>
12776 </parameters>
12777 </event>
12778
12779 <event label="Dynamic Code Generated" phase="any"
12780 id="DynamicCodeGenerated" const="JVMTI_EVENT_DYNAMIC_CODE_GENERATED" num="70">
12781 <description>
12782 Sent when a component of the virtual machine is generated dynamically.
12783 This does not correspond to Java programming language code that is
12784 compiled--see <eventlink id="CompiledMethodLoad"></eventlink>.
12785 This is for native code--for example, an interpreter that is generated
12786 differently depending on command-line options.
12787 <p/>
12788 Note that this event has no controlling capability.
12789 If a VM cannot generate these events, it simply does not send any.
12790 <p/>
12791 These events can be sent after their initial occurrence with
12792 <functionlink id="GenerateEvents"></functionlink>.
12793 </description>
12794 <origin>jvmpi</origin>
12795 <capabilities>
12796 </capabilities>
12797 <parameters>
12798 <param id="name">
12799 <vmbuf><char/></vmbuf>
12800 <description>
12801 Name of the code, encoded as a
12802 <internallink id="mUTF">modified UTF-8</internallink> string.
12803 Intended for display to an end-user.
12804 The name might not be unique.
12805 </description>
12806 </param>
12807 <param id="address">
12808 <vmbuf><void/></vmbuf>
12809 <description>
12810 Native address of the code
12811 </description>
12812 </param>
12813 <param id="length">
12814 <jint/>
12815 <description>
12816 Length in bytes of the code
12817 </description>
12818 </param>
12819 </parameters>
12820 </event>
12821
12822 <event label="Data Dump Request"
12823 id="DataDumpRequest" const="JVMTI_EVENT_DATA_DUMP_REQUEST" num="71">
12824 <description>
12825 Sent by the VM to request the agent to dump its data. This
12826 is just a hint and the agent need not react to this event.
12827 This is useful for processing command-line signals from users. For
12828 example, in the Java 2 SDK a CTRL-Break on Win32 and a CTRL-\ on Solaris
12829 causes the VM to send this event to the agent.
12830 </description>
12831 <origin>jvmpi</origin>
12832 <capabilities>
12833 </capabilities>
12834 <parameters>
12835 </parameters>
12836 </event>
12837
12838 <event label="Monitor Contended Enter"
12839 id="MonitorContendedEnter" const="JVMTI_EVENT_MONITOR_CONTENDED_ENTER" filtered="thread" num="75">
12840 <description>
12841 Sent when a thread is attempting to enter a Java programming language
12842 monitor already acquired by another thread.
12843 </description>
12844 <origin>jvmpi</origin>
12845 <capabilities>
12846 <required id="can_generate_monitor_events"></required>
12847 </capabilities>
12848 <parameters>
12849 <param id="jni_env">
12850 <outptr>
12851 <struct>JNIEnv</struct>
12852 </outptr>
12853 <description>
12854 The JNI environment of the event (current) thread
12855 </description>
12856 </param>
12857 <param id="thread">
12858 <jthread/>
12859 <description>
12860 JNI local reference to the thread
12861 attempting to enter the monitor
12862 </description>
12863 </param>
12864 <param id="object">
12865 <jobject/>
12866 <description>
12867 JNI local reference to the monitor
12868 </description>
12869 </param>
12870 </parameters>
12871 </event>
12872
12873 <event label="Monitor Contended Entered"
12874 id="MonitorContendedEntered" const="JVMTI_EVENT_MONITOR_CONTENDED_ENTERED" filtered="thread" num="76">
12875 <description>
12876 Sent when a thread enters a Java programming language
12877 monitor after waiting for it to be released by another thread.
12878 </description>
12879 <origin>jvmpi</origin>
12880 <capabilities>
12881 <required id="can_generate_monitor_events"></required>
12882 </capabilities>
12883 <parameters>
12884 <param id="jni_env">
12885 <outptr>
12886 <struct>JNIEnv</struct>
12887 </outptr>
12888 <description>
12889 The JNI environment of the event (current) thread
12890 </description>
12891 </param>
12892 <param id="thread">
12893 <jthread/>
12894 <description>
12895 JNI local reference to the thread entering
12896 the monitor
12897 </description>
12898 </param>
12899 <param id="object">
12900 <jobject/>
12901 <description>
12902 JNI local reference to the monitor
12903 </description>
12904 </param>
12905 </parameters>
12906 </event>
12907
12908 <event label="Monitor Wait"
12909 id="MonitorWait" const="JVMTI_EVENT_MONITOR_WAIT" filtered="thread" num="73">
12910 <description>
12911 Sent when a thread is about to wait on an object.
12912 </description>
12913 <origin>jvmpi</origin>
12914 <capabilities>
12915 <required id="can_generate_monitor_events"></required>
12916 </capabilities>
12917 <parameters>
12918 <param id="jni_env">
12919 <outptr>
12920 <struct>JNIEnv</struct>
12921 </outptr>
12922 <description>
12923 The JNI environment of the event (current) thread
12924 </description>
12925 </param>
12926 <param id="thread">
12927 <jthread/>
12928 <description>
12929 JNI local reference to the thread about to wait
12930 </description>
12931 </param>
12932 <param id="object">
12933 <jobject/>
12934 <description>
12935 JNI local reference to the monitor
12936 </description>
12937 </param>
12938 <param id="timeout">
12939 <jlong/>
12940 <description>
12941 The number of milliseconds the thread will wait
12942 </description>
12943 </param>
12944 </parameters>
12945 </event>
12946
12947 <event label="Monitor Waited"
12948 id="MonitorWaited" const="JVMTI_EVENT_MONITOR_WAITED" filtered="thread" num="74">
12949 <description>
12950 Sent when a thread finishes waiting on an object.
12951 </description>
12952 <origin>jvmpi</origin>
12953 <capabilities>
12954 <required id="can_generate_monitor_events"></required>
12955 </capabilities>
12956 <parameters>
12957 <param id="jni_env">
12958 <outptr>
12959 <struct>JNIEnv</struct>
12960 </outptr>
12961 <description>
12962 The JNI environment of the event (current) thread
12963 </description>
12964 </param>
12965 <param id="thread">
12966 <jthread/>
12967 <description>
12968 JNI local reference to the thread that was finished waiting
12969 </description>
12970 </param>
12971 <param id="object">
12972 <jobject/>
12973 <description>
12974 JNI local reference to the monitor.
12975 </description>
12976 </param>
12977 <param id="timed_out">
12978 <jboolean/>
12979 <description>
12980 True if the monitor timed out
12981 </description>
12982 </param>
12983 </parameters>
12984 </event>
12985
12986 <event label="Resource Exhausted"
12987 id="ResourceExhausted" const="JVMTI_EVENT_RESOURCE_EXHAUSTED" num="80"
12988 since="1.1">
12989 <description>
12990 Sent when a VM resource needed by a running application has been exhausted.
12991 Except as required by the optional capabilities, the set of resources
12992 which report exhaustion is implementation dependent.
12993 <p/>
12994 The following bit flags define the properties of the resource exhaustion:
12995 <constants id="jvmtiResourceExhaustionFlags"
12996 label="Resource Exhaustion Flags"
12997 kind="bits"
12998 since="1.1">
12999 <constant id="JVMTI_RESOURCE_EXHAUSTED_OOM_ERROR" num="0x0001">
13000 After this event returns, the VM will throw a
13001 <code>java.lang.OutOfMemoryError</code>.
13002 </constant>
13003 <constant id="JVMTI_RESOURCE_EXHAUSTED_JAVA_HEAP" num="0x0002">
13004 The VM was unable to allocate memory from the <tm>Java</tm>
13005 platform <i>heap</i>.
13006 The <i>heap</i> is the runtime
13007 data area from which memory for all class instances and
13008 arrays are allocated.
13009 </constant>
13010 <constant id="JVMTI_RESOURCE_EXHAUSTED_THREADS" num="0x0004">
13011 The VM was unable to create a thread.
13012 </constant>
13013 </constants>
13014 </description>
13015 <origin>new</origin>
13016 <capabilities>
13017 <capability id="can_generate_resource_exhaustion_heap_events">
13018 Can generate events when the VM is unable to allocate memory from the
13019 <internallink id="JVMTI_RESOURCE_EXHAUSTED_JAVA_HEAP">heap</internallink>.
13020 </capability>
13021 <capability id="can_generate_resource_exhaustion_threads_events">
13022 Can generate events when the VM is unable to
13023 <internallink id="JVMTI_RESOURCE_EXHAUSTED_THREADS">create
13024 a thread</internallink>.
13025 </capability>
13026 </capabilities>
13027 <parameters>
13028 <param id="jni_env">
13029 <outptr>
13030 <struct>JNIEnv</struct>
13031 </outptr>
13032 <description>
13033 The JNI environment of the event (current) thread
13034 </description>
13035 </param>
13036 <param id="flags">
13037 <jint/>
13038 <description>
13039 Flags defining the properties of the of resource exhaustion
13040 as specified by the
13041 <internallink id="jvmtiResourceExhaustionFlags">Resource
13042 Exhaustion Flags</internallink>.
13043 </description>
13044 </param>
13045 <param id="reserved">
13046 <vmbuf><void/></vmbuf>
13047 <description>
13048 Reserved.
13049 </description>
13050 </param>
13051 <param id="description">
13052 <vmbuf><char/></vmbuf>
13053 <description>
13054 Description of the resource exhaustion, encoded as a
13055 <internallink id="mUTF">modified UTF-8</internallink> string.
13056 </description>
13057 </param>
13058 </parameters>
13059 </event>
13060
13061 <event label="VM Object Allocation"
13062 id="VMObjectAlloc" const="JVMTI_EVENT_VM_OBJECT_ALLOC" num="84">
13063 <description>
13064 Sent when a method causes the virtual machine to allocate an
13065 Object visible to Java programming language code and the
13066 allocation is not detectable by other intrumentation mechanisms.
13067 Generally object allocation should be detected by instrumenting
13068 the bytecodes of allocating methods.
13069 Object allocation generated in native code by JNI function
13070 calls should be detected using
13071 <internallink id="jniIntercept">JNI function interception</internallink>.
13072 Some methods might not have associated bytecodes and are not
13073 native methods, they instead are executed directly by the
13074 VM. These methods should send this event.
13075 Virtual machines which are incapable of bytecode instrumentation
13076 for some or all of their methods can send this event.
13077 <p/>
13078 Typical examples where this event might be sent:
13079 <ul>
13080 <li>Reflection -- for example, <code>java.lang.Class.newInstance()</code></li>
13081 <li>Methods not represented by bytecodes -- for example, VM intrinsics and
13082 J2ME preloaded classes</li>
13083 </ul>
13084 Cases where this event would not be generated:
13085 <ul>
13086 <li>Allocation due to bytecodes -- for example, the <code>new</code>
13087 and <code>newarray</code> VM instructions</li>
13088 <li>Allocation due to JNI function calls -- for example,
13089 <code>AllocObject</code></li>
13090 <li>Allocations during VM initialization</li>
13091 <li>VM internal objects</li>
13092 </ul>
13093 </description>
13094 <origin>new</origin>
13095 <capabilities>
13096 <required id="can_generate_vm_object_alloc_events"></required>
13097 </capabilities>
13098 <parameters>
13099 <param id="jni_env">
13100 <outptr>
13101 <struct>JNIEnv</struct>
13102 </outptr>
13103 <description>
13104 The JNI environment of the event (current) thread
13105 </description>
13106 </param>
13107 <param id="thread">
13108 <jthread/>
13109 <description>
13110 Thread allocating the object.
13111 </description>
13112 </param>
13113 <param id="object">
13114 <jobject/>
13115 <description>
13116 JNI local reference to the object that was allocated
13117 </description>
13118 </param>
13119 <param id="object_klass">
13120 <jclass/>
13121 <description>
13122 JNI local reference to the class of the object
13123 </description>
13124 </param>
13125 <param id="size">
13126 <jlong/>
13127 <description>
13128 Size of the object (in bytes). See <functionlink id="GetObjectSize"/>.
13129 </description>
13130 </param>
13131 </parameters>
13132 </event>
13133
13134 <event label="Object Free"
13135 id="ObjectFree" const="JVMTI_EVENT_OBJECT_FREE" num="83">
13136 <description>
13137 An Object Free event is sent when the garbage collector frees an object.
13138 Events are only sent for tagged objects--see
13139 <internallink id="Heap">heap functions</internallink>.
13140 <p/>
13141 The event handler must not use JNI functions and
13142 must not use <jvmti/> functions except those which
13143 specifically allow such use (see the raw monitor, memory management,
13144 and environment local storage functions).
13145 </description>
13146 <origin>new</origin>
13147 <capabilities>
13148 <required id="can_generate_object_free_events"></required>
13149 </capabilities>
13150 <parameters>
13151 <param id="tag">
13152 <jlong/>
13153 <description>
13154 The freed object's tag
13155 </description>
13156 </param>
13157 </parameters>
13158 </event>
13159
13160 <event label="Garbage Collection Start"
13161 id="GarbageCollectionStart" const="JVMTI_EVENT_GARBAGE_COLLECTION_START" num="81">
13162 <description>
13163 A Garbage Collection Start event is sent when a
13164 garbage collection pause begins.
13165 Only stop-the-world collections are reported--that is, collections during
13166 which all threads cease to modify the state of the Java virtual machine.
13167 This means that some collectors will never generate these events.
13168 This event is sent while the VM is still stopped, thus
13169 the event handler must not use JNI functions and
13170 must not use <jvmti/> functions except those which
13171 specifically allow such use (see the raw monitor, memory management,
13172 and environment local storage functions).
13173 <p/>
13174 This event is always sent as a matched pair with
13175 <eventlink id="GarbageCollectionFinish"/>
13176 (assuming both events are enabled) and no garbage collection
13177 events will occur between them.
13178 </description>
13179 <origin>new</origin>
13180 <capabilities>
13181 <required id="can_generate_garbage_collection_events"></required>
13182 </capabilities>
13183 <parameters>
13184 </parameters>
13185 </event>
13186
13187 <event label="Garbage Collection Finish"
13188 id="GarbageCollectionFinish" const="JVMTI_EVENT_GARBAGE_COLLECTION_FINISH" num="82">
13189 <description>
13190 A Garbage Collection Finish event is sent when a
13191 garbage collection pause ends.
13192 This event is sent while the VM is still stopped, thus
13193 the event handler must not use JNI functions and
13194 must not use <jvmti/> functions except those which
13195 specifically allow such use (see the raw monitor, memory management,
13196 and environment local storage functions).
13197 <p/>
13198 Some agents may need to do post garbage collection operations that
13199 require the use of the disallowed <jvmti/> or JNI functions. For these
13200 cases an agent thread can be created which waits on a raw monitor,
13201 and the handler for the Garbage Collection Finish event simply
13202 notifies the raw monitor
13203 <p/>
13204 This event is always sent as a matched pair with
13205 <eventlink id="GarbageCollectionStart"/> (assuming both events are enabled).
13206 <issue>
13207 The most important use of this event is to provide timing information,
13208 and thus additional information is not required. However,
13209 information about the collection which is "free" should be included -
13210 what that information is needs to be determined.
13211 </issue>
13212 </description>
13213 <origin>new</origin>
13214 <capabilities>
13215 <required id="can_generate_garbage_collection_events"></required>
13216 </capabilities>
13217 <parameters>
13218 </parameters>
13219 </event>
13220
13221 <elide>
13222 <event label="Verbose Output" phase="any"
13223 id="VerboseOutput" const="JVMTI_EVENT_VERBOSE_OUTPUT" num="85">
13224 <description>
13225 Send verbose messages as strings.
13226 <issue>
13227 This format is extremely fragile, as it can change with each
13228 platform, collector and version. Alternatives include:
13229 <ul>
13230 <li>building off Java programming language M and M APIs</li>
13231 <li>XML</li>
13232 <li>key/value pairs</li>
13233 <li>removing it</li>
13234 </ul>
13235 </issue>
13236 <issue>
13237 Though this seemed trivial to implement.
13238 In the RI it appears this will be quite complex.
13239 </issue>
13240 </description>
13241 <origin>new</origin>
13242 <capabilities>
13243 </capabilities>
13244 <parameters>
13245 <param id="flag">
13246 <enum>jvmtiVerboseFlag</enum>
13247 <description>
13248 Which verbose output is being sent.
13249 </description>
13250 </param>
13251 <param id="message">
13252 <vmbuf><char/></vmbuf>
13253 <description>
13254 Message text, encoded as a
13255 <internallink id="mUTF">modified UTF-8</internallink> string.
13256 </description>
13257 </param>
13258 </parameters>
13259 </event>
13260 </elide>
13261
13262 </eventsection>
13263
13264 <datasection>
13265 <intro>
13266 <jvmti/> extends the data types defined by JNI.
13267 </intro>
13268 <basetypes id="jniTypes" label="JNI Types Used in the JVM Tool Interface">
13269 <basetype id="jboolean">
13270 <description>
13271 Holds a Java programming language <code>boolean</code>.
13272 Unsigned 8 bits.
13273 </description>
13274 </basetype>
13275 <basetype id="jchar">
13276 <description>
13277 Holds a Java programming language <code>char</code>.
13278 Unsigned 16 bits.
13279 </description>
13280 </basetype>
13281 <basetype id="jint">
13282 <description>
13283 Holds a Java programming language <code>int</code>.
13284 Signed 32 bits.
13285 </description>
13286 </basetype>
13287 <basetype id="jlong">
13288 <description>
13289 Holds a Java programming language <code>long</code>.
13290 Signed 64 bits.
13291 </description>
13292 </basetype>
13293 <basetype id="jfloat">
13294 <description>
13295 Holds a Java programming language <code>float</code>.
13296 32 bits.
13297 </description>
13298 </basetype>
13299 <basetype id="jdouble">
13300 <description>
13301 Holds a Java programming language <code>double</code>.
13302 64 bits.
13303 </description>
13304 </basetype>
13305 <basetype id="jobject">
13306 <description>
13307 Holds a Java programming language object.
13308 </description>
13309 </basetype>
13310 <basetype id="jclass">
13311 <description>
13312 Holds a Java programming language class.
13313 </description>
13314 </basetype>
13315 <basetype id="jvalue">
13316 <description>
13317 Is a union of all primitive types and <code>jobject</code>. Thus, holds any Java
13318 programming language value.
13319 </description>
13320 </basetype>
13321 <basetype id="jfieldID">
13322 <description>
13323 Identifies a Java programming language field.
13324 <code>jfieldID</code>s returned by <jvmti/> functions and events may be
13325 safely stored.
13326 </description>
13327 </basetype>
13328 <basetype id="jmethodID">
13329 <description>
13330 Identifies a Java programming language method, initializer, or constructor.
13331 <code>jmethodID</code>s returned by <jvmti/> functions and events may be
13332 safely stored. However, if the class is unloaded, they become invalid
13333 and must not be used.
13334 </description>
13335 </basetype>
13336 <basetype id="JNIEnv">
13337 <description>
13338 Pointer to the JNI function table. Pointer to this (<code>JNIEnv *</code>)
13339 is a JNI environment.
13340 </description>
13341 </basetype>
13342 </basetypes>
13343
13344 <basetypes id="jvmtiTypes" label="JVM Tool Interface Base Types">
13345 <basetype id="jvmtiEnv">
13346 <description>
13347 The <jvmti/> <internallink id="environments">environment</internallink> pointer.
13348 See the <internallink id="FunctionSection">Function Section</internallink>.
13349 <code>jvmtiEnv</code> points to the
13350 <internallink id="FunctionTable">function table</internallink> pointer.
13351 </description>
13352 </basetype>
13353 <basetype id="jthread">
13354 <definition>typedef jobject jthread;</definition>
13355 <description>
13356 Subtype of <datalink id="jobject"></datalink> that holds a thread.
13357 </description>
13358 </basetype>
13359 <basetype id="jthreadGroup">
13360 <definition>typedef jobject jthreadGroup;</definition>
13361 <description>
13362 Subtype of <datalink id="jobject"></datalink> that holds a thread group.
13363 </description>
13364 </basetype>
13365 <basetype id="jlocation">
13366 <definition>typedef jlong jlocation;</definition>
13367 <description>
13368 A 64 bit value, representing a monotonically increasing
13369 executable position within a method.
13370 <code>-1</code> indicates a native method.
13371 See <functionlink id="GetJLocationFormat"></functionlink> for the format on a
13372 given VM.
13373 </description>
13374 </basetype>
13375 <basetype id="jrawMonitorID">
13376 <definition>struct _jrawMonitorID;
13377 typedef struct _jrawMonitorID *jrawMonitorID;</definition>
13378 <description>
13379 A raw monitor.
13380 </description>
13381 </basetype>
13382 <basetype id="jvmtiError">
13383 <description>
13384 Holds an error return code.
13385 See the <internallink id="ErrorSection">Error section</internallink> for possible values.
13386 <example>
13387 typedef enum {
13388 JVMTI_ERROR_NONE = 0,
13389 JVMTI_ERROR_INVALID_THREAD = 10,
13390 ...
13391 } jvmtiError;
13392 </example>
13393 </description>
13394 </basetype>
13395 <basetype id="jvmtiEvent">
13396 <description>
13397 An identifier for an event type.
13398 See the <internallink id="EventSection">Event section</internallink> for possible values.
13399 It is guaranteed that future versions of this specification will
13400 never assign zero as an event type identifier.
13401 <example>
13402 typedef enum {
13403 JVMTI_EVENT_SINGLE_STEP = 1,
13404 JVMTI_EVENT_BREAKPOINT = 2,
13405 ...
13406 } jvmtiEvent;
13407 </example>
13408 </description>
13409 </basetype>
13410 <basetype id="jvmtiEventCallbacks">
13411 <description>
13412 The callbacks used for events.
13413 <example>
13414 typedef struct {
13415 jvmtiEventVMInit VMInit;
13416 jvmtiEventVMDeath VMDeath;
13417 ...
13418 } jvmtiEventCallbacks;
13419 </example>
13420 See <internallink id="jvmtiEventCallbacks">event callbacks</internallink>
13421 for the complete structure.
13422 <p/>
13423 Where, for example, the VM initialization callback is defined:
13424 <example>
13425 typedef void (JNICALL *jvmtiEventVMInit)
13426 (jvmtiEnv *jvmti_env,
13427 JNIEnv* jni_env,
13428 jthread thread);
13429 </example>
13430 See the individual events for the callback function definition.
13431 </description>
13432 </basetype>
13433 <basetype id="jniNativeInterface">
13434 <definition>typedef struct JNINativeInterface_ jniNativeInterface;</definition>
13435 <description>
13436 Typedef for the JNI function table <code>JNINativeInterface</code>
13437 defined in the
13438 <externallink id="http://docs.oracle.com/javase/7/docs/technotes/guides/jni/spec/functions.html#wp23720">JNI Specification</externallink>.
13439 The JNI reference implementation defines this with an underscore.
13440 </description>
13441 </basetype>
13442 </basetypes>
13443
13444 </datasection>
13445
13446 <issuessection label="Issues">
13447 <intro id="suspendRequired" label="Resolved Issue: Suspend - Required or Automatic">
13448 JVMDI requires that the agent suspend threads before calling
13449 certain sensitive functions. JVMPI requires garbage collection to be
13450 disabled before calling certain sensitive functions.
13451 It was suggested that rather than have this requirement, that
13452 VM place itself in a suitable state before performing an
13453 operation. This makes considerable sense since each VM
13454 knows its requirements and can most easily arrange a
13455 safe state.
13456 <p/>
13457 The ability to externally suspend/resume threads will, of
13458 course, remain. The ability to enable/disable garbage collection will not.
13459 <p/>
13460 This issue is resolved--suspend will not
13461 be required. The spec has been updated to reflect this.
13462 </intro>
13463
13464 <intro id="stackSampling" label="Resolved Issue: Call Stack Sampling">
13465 There are a variety of approaches to sampling call stacks.
13466 The biggest bifurcation is between VM controlled and agent
13467 controlled.
13468 <p/>
13469 This issue is resolved--agent controlled
13470 sampling will be the approach.
13471 </intro>
13472
13473 <intro id="threadRepresentation" label="Resolved Issue: Thread Representation">
13474 JVMDI represents threads as jthread. JVMPI primarily
13475 uses JNIEnv* to represent threads.
13476 <p/>
13477 The Expert Group has chosen jthread as the representation
13478 for threads in <jvmti/>.
13479 JNIEnv* is sent by
13480 events since it is needed to JNI functions. JNIEnv, per the
13481 JNI spec, are not supposed to be used outside their thread.
13482 </intro>
13483
13484 <intro id="design" label="Resolved Issue: Method Representation">
13485 The JNI spec allows an implementation to depend on jclass/jmethodID
13486 pairs, rather than simply a jmethodID, to reference a method.
13487 JVMDI, for consistency, choose the same representation.
13488 JVMPI, however, specifies that a jmethodID alone maps to a
13489 method. Both of the Sun <tm>J2SE</tm> virtual machines (Classic and <tm>HotSpot</tm>) store
13490 pointers in jmethodIDs, and as a result, a jmethodID is sufficient.
13491 In fact, any JVM implementation that supports JVMPI must have
13492 such a representation.
13493 <jvmti/> will use jmethodID as a unique representation of a method
13494 (no jclass is used).
13495 There should be efficiency gains, particularly in
13496 functionality like stack dumping, to this representation.
13497 <p/>
13498 Note that fields were not used in JVMPI and that the access profile
13499 of fields differs from methods--for implementation efficiency
13500 reasons, a jclass/jfieldID pair will still be needed for field
13501 reference.
13502 </intro>
13503
13504 <intro id="localReferenceIssue" label="Resolved Issue: Local References">
13505 Functions return local references.
13506 </intro>
13507
13508 <intro id="frameRep" label="Resolved Issue: Representation of frames">
13509 In JVMDI, a frame ID is used to represent a frame. Problem with this
13510 is that a VM must track when a frame becomes invalid, a far better
13511 approach, and the one used in <jvmti/>, is to reference frames by depth.
13512 </intro>
13513
13514 <intro id="requiredCapabilities" label="Issue: Required Capabilities">
13515 Currently, having a required capabilities means that the functionality
13516 is optional. Capabilities are useful even for required functionality
13517 since they can inform the VM is needed set-up. Thus, there should be
13518 a set of capabilities that a conformant implementation must provide
13519 (if requested during Agent_OnLoad).
13520 </intro>
13521
13522 <intro id="taghint" label="Proposal: add tag hint function">
13523 A hint of the percentage of objects that will be tagged would
13524 help the VM pick a good implementation.
13525 </intro>
13526
13527 <intro id="moreMonitorQueries" label="Request: More Monitor Quires">
13528 How difficult or easy would be to extend the monitor_info category to include
13529 <pre>
13530 - current number of monitors
13531 - enumeration of monitors
13532 - enumeration of threads waiting on a given monitor
13533 </pre>
13534 The reason for my question is the fact that current get_monitor_info support
13535 requires the agent to specify a given thread to get the info which is probably
13536 OK in the profiling/debugging space, while in the monitoring space the agent
13537 could be watching the monitor list and then decide which thread to ask for
13538 the info. You might ask why is this important for monitoring .... I think it
13539 can aid in the detection/prediction of application contention caused by hot-locks.
13540 </intro>
13541 </issuessection>
13542
13543 <changehistory id="ChangeHistory" update="09/05/07">
13544 <intro>
13545 The <jvmti/> specification is an evolving document with major, minor,
13546 and micro version numbers.
13547 A released version of the specification is uniquely identified
13548 by its major and minor version.
13549 The functions, events, and capabilities in this specification
13550 indicate a "Since" value which is the major and minor version in
13551 which it was introduced.
13552 The version of the specification implemented by the VM can
13553 be retrieved at runtime with the <functionlink id="GetVersionNumber"/>
13554 function.
13555 </intro>
13556 <change date="14 Nov 2002">
13557 Converted to XML document.
13558 </change>
13559 <change date="14 Nov 2002">
13560 Elided heap dump functions (for now) since what was there
13561 was wrong.
13562 </change>
13563 <change date="18 Nov 2002">
13564 Added detail throughout.
13565 </change>
13566 <change date="18 Nov 2002">
13567 Changed JVMTI_THREAD_STATUS_RUNNING to JVMTI_THREAD_STATUS_RUNNABLE.
13568 </change>
13569 <change date="19 Nov 2002">
13570 Added AsyncGetStackTrace.
13571 </change>
13572 <change date="19 Nov 2002">
13573 Added jframeID return to GetStackTrace.
13574 </change>
13575 <change date="19 Nov 2002">
13576 Elided GetCurrentFrame and GetCallingFrame functions (for now) since what was there
13577 since they are redundant with GetStackTrace.
13578 </change>
13579 <change date="19 Nov 2002">
13580 Elided ClearAllBreakpoints since it has always been redundant.
13581 </change>
13582 <change date="19 Nov 2002">
13583 Added GetSystemProperties.
13584 </change>
13585 <change date="19 Nov 2002">
13586 Changed the thread local storage functions to use jthread.
13587 </change>
13588 <change date="20 Nov 2002">
13589 Added GetJLocationFormat.
13590 </change>
13591 <change date="22 Nov 2002">
13592 Added events and introductory text.
13593 </change>
13594 <change date="22 Nov 2002">
13595 Cross reference type and constant definitions.
13596 </change>
13597 <change date="24 Nov 2002">
13598 Added DTD.
13599 </change>
13600 <change date="24 Nov 2002">
13601 Added capabilities function section.
13602 </change>
13603 <change date="29 Nov 2002">
13604 Assign capabilities to each function and event.
13605 </change>
13606 <change date="29 Nov 2002">
13607 Add <internallink id="jniIntercept">JNI interception functions</internallink>.
13608 </change>
13609 <change date="30 Nov 2002">
13610 Auto generate SetEventNotificationMode capabilities.
13611 </change>
13612 <change date="30 Nov 2002">
13613 Add <eventlink id="VMObjectAlloc"></eventlink> event.
13614 </change>
13615 <change date="30 Nov 2002">
13616 Add <eventlink id="DynamicCodeGenerated"></eventlink> event.
13617 </change>
13618 <change date="30 Nov 2002">
13619 Add const to declarations.
13620 </change>
13621 <change date="30 Nov 2002">
13622 Change method exit and frame pop to send on exception.
13623 </change>
13624 <change date="1 Dec 2002">
13625 Add ForceGarbageCollection.
13626 </change>
13627 <change date="2 Dec 2002">
13628 Redo Xrun section; clarify GetStackTrace and add example;
13629 Fix width problems; use "agent" consistently.
13630 </change>
13631 <change date="8 Dec 2002">
13632 Remove previous start-up intro.
13633 Add <internallink id="environments"><jvmti/> Environments</internallink>
13634 section.
13635 </change>
13636 <change date="8 Dec 2002">
13637 Add <functionlink id="DisposeEnvironment"></functionlink>.
13638 </change>
13639 <change date="9 Dec 2002">
13640 Numerous minor updates.
13641 </change>
13642 <change date="15 Dec 2002">
13643 Add heap profiling functions added:
13644 get/set annotation, iterate live objects/heap.
13645 Add heap profiling functions place holder added:
13646 heap roots.
13647 Heap profiling event added: object free.
13648 Heap profiling event redesigned: vm object allocation.
13649 Heap profiling event placeholders added: garbage collection start/finish.
13650 Native method bind event added.
13651 </change>
13652 <change date="19 Dec 2002">
13653 Revamp suspend/resume functions.
13654 Add origin information with jvmdi tag.
13655 Misc fixes.
13656 </change>
13657 <change date="24 Dec 2002">
13658 Add semantics to types.
13659 </change>
13660 <change date="27 Dec 2002">
13661 Add local reference section.
13662 Autogenerate parameter descriptions from types.
13663 </change>
13664 <change date="28 Dec 2002">
13665 Document that RunAgentThread sends threadStart.
13666 </change>
13667 <change date="29 Dec 2002">
13668 Remove redundant local ref and dealloc warning.
13669 Convert GetRawMonitorName to allocated buffer.
13670 Add GenerateEvents.
13671 </change>
13672 <change date="30 Dec 2002">
13673 Make raw monitors a type and rename to "jrawMonitorID".
13674 </change>
13675 <change date="1 Jan 2003">
13676 Include origin information.
13677 Clean-up JVMDI issue references.
13678 Remove Deallocate warnings which are now automatically generated.
13679 </change>
13680 <change date="2 Jan 2003">
13681 Fix representation issues for jthread.
13682 </change>
13683 <change date="3 Jan 2003">
13684 Make capabilities buffered out to 64 bits - and do it automatically.
13685 </change>
13686 <change date="4 Jan 2003">
13687 Make constants which are enumeration into enum types.
13688 Parameters now of enum type.
13689 Clean-up and index type section.
13690 Replace remaining datadef entities with callback.
13691 </change>
13692 <change date="7 Jan 2003">
13693 Correct GenerateEvents description.
13694 More internal semantics work.
13695 </change>
13696 <change date="9 Jan 2003">
13697 Replace previous GetSystemProperties with two functions
13698 which use allocated information instead fixed.
13699 Add SetSystemProperty.
13700 More internal semantics work.
13701 </change>
13702 <change date="12 Jan 2003">
13703 Add varargs to end of SetEventNotificationMode.
13704 </change>
13705 <change date="20 Jan 2003">
13706 Finish fixing spec to reflect that alloc sizes are jlong.
13707 </change>
13708 <change date="22 Jan 2003">
13709 Allow NULL as RunAgentThread arg.
13710 </change>
13711 <change date="22 Jan 2003">
13712 Fixed names to standardized naming convention
13713 Removed AsyncGetStackTrace.
13714 </change>
13715 <change date="29 Jan 2003">
13716 Since we are using jthread, removed GetThread.
13717 </change>
13718 <change date="31 Jan 2003">
13719 Change GetFieldName to allow NULLs like GetMethodName.
13720 </change>
13721 <change date="29 Feb 2003" version="v40">
13722 Rewrite the introductory text, adding sections on
13723 start-up, environments and bytecode instrumentation.
13724 Change the command line arguments per EG discussions.
13725 Add an introduction to the capabilities section.
13726 Add the extension mechanism category and functions.
13727 Mark for deletion, but clarified anyhow, SuspendAllThreads.
13728 Rename IterateOverLiveObjects to IterateOverReachableObjects and
13729 change the text accordingly.
13730 Clarify IterateOverHeap.
13731 Clarify CompiledMethodLoad.
13732 Discuss prerequisite state for Calling Functions.
13733 Clarify SetAllocationHooks.
13734 Added issues ("To be resolved:") through-out.
13735 And so on...
13736 </change>
13737 <change date="6 Mar 2003" version="v41">
13738 Remove struct from the call to GetOwnedMonitorInfo.
13739 Automatically generate most error documentation, remove
13740 (rather broken) hand written error doc.
13741 Better describe capability use (empty initial set).
13742 Add min value to jint params.
13743 Remove the capability can_access_thread_local_storage.
13744 Rename error JVMTI_ERROR_NOT_IMPLEMENTED to JVMTI_ERROR_MUST_POSSESS_CAPABILITY;
13745 same for *NOT_IMPLEMENTED.
13746 Description fixes.
13747 </change>
13748 <change date="8 Mar 2003" version="v42">
13749 Rename GetClassSignature to GetClassName.
13750 Rename IterateOverClassObjects to IterateOverInstancesOfClass.
13751 Remove GetMaxStack (operand stack isn't used in <jvmti/>).
13752 Description fixes: define launch-time, remove native frame pop
13753 from PopFrame, and assorted clarifications.
13754 </change>
13755 <change date="8 Mar 2003" version="v43">
13756 Fix minor editing problem.
13757 </change>
13758 <change date="10 Mar 2003" version="v44">
13759 Add phase information.
13760 Remap (compact) event numbers.
13761 </change>
13762 <change date="11 Mar 2003" version="v45">
13763 More phase information - allow "any".
13764 Elide raw monitor queries and events.
13765 Minor description fixes.
13766 </change>
13767 <change date="12 Mar 2003" version="v46">
13768 Add GetPhase.
13769 Use "phase" through document.
13770 Elide GetRawMonitorName.
13771 Elide GetObjectMonitors.
13772 </change>
13773 <change date="12 Mar 2003" version="v47">
13774 Fixes from link, XML, and spell checking.
13775 Auto-generate the callback structure.
13776 </change>
13777 <change date="13 Mar 2003" version="v48">
13778 One character XML fix.
13779 </change>
13780 <change date="13 Mar 2003" version="v49">
13781 Change function parameter names to be consistent with
13782 event parameters (fooBarBaz becomes foo_bar_baz).
13783 </change>
13784 <change date="14 Mar 2003" version="v50">
13785 Fix broken link. Fix thread markers.
13786 </change>
13787 <change date="14 Mar 2003" version="v51">
13788 Change constants so they are under 128 to workaround
13789 compiler problems.
13790 </change>
13791 <change date="23 Mar 2003" version="v52">
13792 Overhaul capabilities. Separate GetStackTrace into
13793 GetStackTrace and GetStackFrames.
13794 </change>
13795 <change date="8 Apr 2003" version="v54">
13796 Use depth instead of jframeID to reference frames.
13797 Remove the now irrelevant GetCurrentFrame, GetCallerFrame and GetStackFrames.
13798 Remove frame arg from events.
13799 </change>
13800 <change date="9 Apr 2003" version="v55">
13801 Remove GetObjectWithAnnotation since tests show bufferred approach more efficient.
13802 Add missing annotation_count to GetObjectsWithAnnotations
13803 </change>
13804 <change date="10 Apr 2003" version="v56">
13805 Remove confusing parenthetical statement in GetObjectsWithAnnotations
13806 </change>
13807 <change date="13 Apr 2003" version="v58">
13808 Replace jclass/jmethodID representation of method with simply jmethodID;
13809 Pass JvmtiEnv* as first arg of every event; remove JNIEnv* where inappropriate.
13810 Replace can_access_frames with can_access_local_variables; remove from purely stack access.
13811 Use can_get_synthetic_attribute; fix description.
13812 Clarify that zero length arrays must be deallocated.
13813 Clarify RelinquishCapabilities.
13814 Generalize JVMTI_ERROR_VM_DEAD to JVMTI_ERROR_WRONG_PHASE.
13815 </change>
13816 <change date="27 Apr 2003" version="v59">
13817 Remove lingering indirect references to OBSOLETE_METHOD_ID.
13818 </change>
13819 <change date="4 May 2003" version="v60">
13820 Allow DestroyRawMonitor during OnLoad.
13821 </change>
13822 <change date="7 May 2003" version="v61">
13823 Added not monitor owner error return to DestroyRawMonitor.
13824 </change>
13825 <change date="13 May 2003" version="v62">
13826 Clarify semantics of raw monitors.
13827 Change flags on <code>GetThreadStatus</code>.
13828 <code>GetClassLoader</code> return NULL for the bootstrap class loader.
13829 Add <code>GetClassName</code> issue.
13830 Define local variable signature.
13831 Disallow zero in annotations array of <code>GetObjectsWithAnnotations</code>.
13832 Remove over specification in <code>GetObjectsWithAnnotations</code>.
13833 Elide <code>SetAllocationHooks</code>.
13834 Elide <code>SuspendAllThreads</code>.
13835 </change>
13836 <change date="14 May 2003" version="v63">
13837 Define the data type <code>jvmtiEventCallbacks</code>.
13838 Zero length allocations return NULL.
13839 Keep SetAllocationHooks in JVMDI, but remove from <jvmti/>.
13840 Add JVMTI_THREAD_STATUS_FLAG_INTERRUPTED.
13841 </change>
13842 <change date="15 May 2003" version="v64">
13843 Better wording, per review.
13844 </change>
13845 <change date="15 May 2003" version="v65">
13846 First Alpha.
13847 Make jmethodID and jfieldID unique, jclass not used.
13848 </change>
13849 <change date="27 May 2003" version="v66">
13850 Fix minor XSLT errors.
13851 </change>
13852 <change date="13 June 2003" version="v67">
13853 Undo making jfieldID unique (jmethodID still is).
13854 </change>
13855 <change date="17 June 2003" version="v68">
13856 Changes per June 11th Expert Group meeting --
13857 Overhaul Heap functionality: single callback,
13858 remove GetHeapRoots, add reachable iterators,
13859 and rename "annotation" to "tag".
13860 NULL thread parameter on most functions is current
13861 thread.
13862 Add timers.
13863 Remove ForceExit.
13864 Add GetEnvironmentLocalStorage.
13865 Add verbose flag and event.
13866 Add AddToBootstrapClassLoaderSearch.
13867 Update ClassFileLoadHook.
13868 </change>
13869 <change date="18 June 2003" version="v69">
13870 Clean up issues sections.
13871 Rename GetClassName back to GetClassSignature and
13872 fix description.
13873 Add generic signature to GetClassSignature,
13874 GetFieldSignature, GetMethodSignature, and
13875 GetLocalVariableTable.
13876 Elide EstimateCostOfCapabilities.
13877 Clarify that the system property functions operate
13878 on the VM view of system properties.
13879 Clarify Agent_OnLoad.
13880 Remove "const" from JNIEnv* in events.
13881 Add metadata accessors.
13882 </change>
13883 <change date="18 June 2003" version="v70">
13884 Add start_depth to GetStackTrace.
13885 Move system properties to a new category.
13886 Add GetObjectSize.
13887 Remove "X" from command line flags.
13888 XML, HTML, and spell check corrections.
13889 </change>
13890 <change date="19 June 2003" version="v71">
13891 Fix JVMTI_HEAP_ROOT_THREAD to be 6.
13892 Make each synopsis match the function name.
13893 Fix unclear wording.
13894 </change>
13895 <change date="26 June 2003" version="v72">
13896 SetThreadLocalStorage and SetEnvironmentLocalStorage should allow value
13897 to be set to NULL.
13898 NotifyFramePop, GetFrameLocationm and all the local variable operations
13899 needed to have their wording about frames fixed.
13900 Grammar and clarity need to be fixed throughout.
13901 Capitalization and puntuation need to be consistent.
13902 Need micro version number and masks for accessing major, minor, and micro.
13903 The error code lists should indicate which must be returned by
13904 an implementation.
13905 The command line properties should be visible in the properties functions.
13906 Disallow popping from the current thread.
13907 Allow implementations to return opaque frame error when they cannot pop.
13908 The NativeMethodBind event should be sent during any phase.
13909 The DynamicCodeGenerated event should be sent during any phase.
13910 The following functions should be allowed to operate before VMInit:
13911 Set/GetEnvironmentLocalStorage
13912 GetMethodDeclaringClass
13913 GetClassSignature
13914 GetClassModifiers
13915 IsInterface
13916 IsArrayClass
13917 GetMethodName
13918 GetMethodModifiers
13919 GetMaxLocals
13920 GetArgumentsSize
13921 GetLineNumberTable
13922 GetMethodLocation
13923 IsMethodNative
13924 IsMethodSynthetic.
13925 Other changes (to XSL):
13926 Argument description should show asterisk after not before pointers.
13927 NotifyFramePop, GetFrameLocationm and all the local variable operations
13928 should hsve the NO_MORE_FRAMES error added.
13929 Not alive threads should have a different error return than invalid thread.
13930 </change>
13931 <change date="7 July 2003" version="v73">
13932 VerboseOutput event was missing message parameter.
13933 Minor fix-ups.
13934 </change>
13935 <change date="14 July 2003" version="v74">
13936 Technical Publications Department corrections.
13937 Allow thread and environment local storage to be set to NULL.
13938 </change>
13939 <change date="23 July 2003" version="v75">
13940 Use new Agent_OnLoad rather than overloaded JVM_OnLoad.
13941 Add JNICALL to callbacks (XSL).
13942 Document JNICALL requirement for both events and callbacks (XSL).
13943 Restrict RedefineClasses to methods and attributes.
13944 Elide the VerboseOutput event.
13945 VMObjectAlloc: restrict when event is sent and remove method parameter.
13946 Finish loose ends from Tech Pubs edit.
13947 </change>
13948 <change date="24 July 2003" version="v76">
13949 Change ClassFileLoadHook event to send the class instead of a boolean of redefine.
13950 </change>
13951 <change date="24 July 2003" version="v77">
13952 XML fixes.
13953 Minor text clarifications and corrections.
13954 </change>
13955 <change date="24 July 2003" version="v78">
13956 Remove GetExceptionHandlerTable and GetThrownExceptions from <jvmti/>.
13957 Clarify that stack frames are JVM Spec frames.
13958 Split can_get_source_info into can_get_source_file_name, can_get_line_numbers,
13959 and can_get_source_debug_extension.
13960 PopFrame cannot have a native calling method.
13961 Removed incorrect statement in GetClassloaderClasses
13962 (see <vmspec chapter="4.4"/>).
13963 </change>
13964 <change date="24 July 2003" version="v79">
13965 XML and text fixes.
13966 Move stack frame description into Stack Frame category.
13967 </change>
13968 <change date="26 July 2003" version="v80">
13969 Allow NULL (means bootstrap loader) for GetClassloaderClasses.
13970 Add new heap reference kinds for references from classes.
13971 Add timer information struct and query functions.
13972 Add AvailableProcessors.
13973 Rename GetOtherThreadCpuTime to GetThreadCpuTime.
13974 Explicitly add JVMTI_ERROR_INVALID_THREAD and JVMTI_ERROR_THREAD_NOT_ALIVE
13975 to SetEventNotification mode.
13976 Add initial thread to the VM_INIT event.
13977 Remove platform assumptions from AddToBootstrapClassLoaderSearch.
13978 </change>
13979 <change date="26 July 2003" version="v81">
13980 Grammar and clarity changes per review.
13981 </change>
13982 <change date="27 July 2003" version="v82">
13983 More grammar and clarity changes per review.
13984 Add Agent_OnUnload.
13985 </change>
13986 <change date="28 July 2003" version="v83">
13987 Change return type of Agent_OnUnload to void.
13988 </change>
13989 <change date="28 July 2003" version="v84">
13990 Rename JVMTI_REFERENCE_ARRAY to JVMTI_REFERENCE_ARRAY_ELEMENT.
13991 </change>
13992 <change date="28 July 2003" version="v85">
13993 Steal java.lang.Runtime.availableProcessors() wording for
13994 AvailableProcessors().
13995 Guarantee that zero will never be an event ID.
13996 Remove some issues which are no longer issues.
13997 Per review, rename and more completely document the timer
13998 information functions.
13999 </change>
14000 <change date="29 July 2003" version="v86">
14001 Non-spec visible change to XML controlled implementation:
14002 SetThreadLocalStorage must run in VM mode.
14003 </change>
14004 <change date="5 August 2003" version="0.1.87">
14005 Add GetErrorName.
14006 Add varargs warning to jvmtiExtensionEvent.
14007 Remove "const" on the jvmtiEnv* of jvmtiExtensionEvent.
14008 Remove unused can_get_exception_info capability.
14009 Pass jvmtiEnv* and JNIEnv* to the jvmtiStartFunction.
14010 Fix jvmtiExtensionFunctionInfo.func declared type.
14011 Extension function returns error code.
14012 Use new version numbering.
14013 </change>
14014 <change date="5 August 2003" version="0.2.88">
14015 Remove the ClassUnload event.
14016 </change>
14017 <change date="8 August 2003" version="0.2.89">
14018 Heap reference iterator callbacks return an enum that
14019 allows outgoing object references to be ignored.
14020 Allow JNIEnv as a param type to extension events/functions.
14021 </change>
14022 <change date="15 August 2003" version="0.2.90">
14023 Fix a typo.
14024 </change>
14025 <change date="2 September 2003" version="0.2.91">
14026 Remove all metadata functions: GetClassMetadata,
14027 GetFieldMetadata, and GetMethodMetadata.
14028 </change>
14029 <change date="1 October 2003" version="0.2.92">
14030 Mark the functions Allocate. Deallocate, RawMonitor*,
14031 SetEnvironmentLocalStorage, and GetEnvironmentLocalStorage
14032 as safe for use in heap callbacks and GC events.
14033 </change>
14034 <change date="24 November 2003" version="0.2.93">
14035 Add pass through opaque user data pointer to heap iterate
14036 functions and callbacks.
14037 In the CompiledMethodUnload event, send the code address.
14038 Add GarbageCollectionOccurred event.
14039 Add constant pool reference kind.
14040 Mark the functions CreateRawMonitor and DestroyRawMonitor
14041 as safe for use in heap callbacks and GC events.
14042 Clarify: VMDeath, GetCurrentThreadCpuTimerInfo,
14043 GetThreadCpuTimerInfo, IterateOverReachableObjects,
14044 IterateOverObjectsReachableFromObject, GetTime and
14045 JVMTI_ERROR_NULL_POINTER.
14046 Add missing errors to: GenerateEvents and
14047 AddToBootstrapClassLoaderSearch.
14048 Fix description of ClassFileLoadHook name parameter.
14049 In heap callbacks and GC/ObjectFree events, specify
14050 that only explicitly allowed functions can be called.
14051 Allow GetCurrentThreadCpuTimerInfo, GetCurrentThreadCpuTime,
14052 GetTimerInfo, and GetTime during callback.
14053 Allow calling SetTag/GetTag during the onload phase.
14054 SetEventNotificationMode, add: error attempted inappropriate
14055 thread level control.
14056 Remove jvmtiExceptionHandlerEntry.
14057 Fix handling of native methods on the stack --
14058 location_ptr param of GetFrameLocation, remove
14059 JVMTI_ERROR_OPAQUE_FRAME from GetFrameLocation,
14060 jvmtiFrameInfo.location, and jlocation.
14061 Remove typo (from JVMPI) implying that the MonitorWaited
14062 event is sent on sleep.
14063 </change>
14064 <change date="25 November 2003" version="0.2.94">
14065 Clarifications and typos.
14066 </change>
14067 <change date="3 December 2003" version="0.2.95">
14068 Allow NULL user_data in heap iterators.
14069 </change>
14070 <change date="28 January 2004" version="0.2.97">
14071 Add GetThreadState, deprecate GetThreadStatus.
14072 </change>
14073 <change date="29 January 2004" version="0.2.98">
14074 INVALID_SLOT and TYPE_MISMATCH errors should be optional.
14075 </change>
14076 <change date="12 February 2004" version="0.2.102">
14077 Remove MonitorContendedExit.
14078 Added JNIEnv parameter to VMObjectAlloc.
14079 Clarified definition of class_tag and referrer_index
14080 parameters to heap callbacks.
14081 </change>
14082 <change date="16 Febuary 2004" version="0.2.103">
14083 Document JAVA_TOOL_OPTIONS.
14084 </change>
14085 <change date="17 Febuary 2004" version="0.2.105">
14086 Divide start phase into primordial and start.
14087 Add VMStart event
14088 Change phase associations of functions and events.
14089 </change>
14090 <change date="18 Febuary 2004" version="0.3.6">
14091 Elide deprecated GetThreadStatus.
14092 Bump minor version, subtract 100 from micro version
14093 </change>
14094 <change date="18 Febuary 2004" version="0.3.7">
14095 Document that timer nanosecond values are unsigned.
14096 Clarify text having to do with native methods.
14097 </change>
14098 <change date="19 Febuary 2004" version="0.3.8">
14099 Fix typos.
14100 Remove elided deprecated GetThreadStatus.
14101 </change>
14102 <change date="23 Febuary 2004" version="0.3.9">
14103 Require NotifyFramePop to act on suspended threads.
14104 </change>
14105 <change date="24 Febuary 2004" version="0.3.10">
14106 Add capabilities
14107 (<internallink id="jvmtiCapabilities.can_redefine_any_class"
14108 ><code>can_redefine_any_class</code></internallink>
14109 and
14110 <internallink id="jvmtiCapabilities.can_generate_all_class_hook_events"
14111 ><code>can_generate_all_class_hook_events</code></internallink>)
14112 and an error (<errorlink id="JVMTI_ERROR_UNMODIFIABLE_CLASS"></errorlink>)
14113 which allow some classes to be unmodifiable.
14114 </change>
14115 <change date="28 Febuary 2004" version="0.3.11">
14116 Add JVMTI_ERROR_MUST_POSSESS_CAPABILITY to SetEventNotificationMode.
14117 </change>
14118 <change date="8 March 2004" version="0.3.12">
14119 Clarified CompiledMethodUnload so that it is clear the event
14120 may be posted after the class has been unloaded.
14121 </change>
14122 <change date="5 March 2004" version="0.3.13">
14123 Change the size parameter of VMObjectAlloc to jlong to match GetObjectSize.
14124 </change>
14125 <change date="13 March 2004" version="0.3.14">
14126 Added guideline for the use of the JNI FindClass function in event
14127 callback functions.
14128 </change>
14129 <change date="15 March 2004" version="0.3.15">
14130 Add GetAllStackTraces and GetThreadListStackTraces.
14131 </change>
14132 <change date="19 March 2004" version="0.3.16">
14133 ClassLoad and ClassPrepare events can be posted during start phase.
14134 </change>
14135 <change date="25 March 2004" version="0.3.17">
14136 Add JVMTI_ERROR_NATIVE_METHOD to GetLineNumberTable, GetLocalVariableTable,
14137 GetMaxLocals, GetArgumentsSize, GetMethodLocation, GetBytecodes.
14138 </change>
14139 <change date="29 March 2004" version="0.3.18">
14140 Return the timer kind in the timer information structure.
14141 </change>
14142 <change date="31 March 2004" version="0.3.19">
14143 Spec clarifications:
14144 JVMTI_THREAD_STATE_IN_NATIVE might not include JNI or <jvmti/>.
14145 ForceGarbageCollection does not run finalizers.
14146 The context of the specification is the Java platform.
14147 Warn about early instrumentation.
14148 </change>
14149 <change date="1 April 2004" version="0.3.20">
14150 Refinements to the above clarifications and
14151 Clarify that an error returned by Agent_OnLoad terminates the VM.
14152 </change>
14153 <change date="1 April 2004" version="0.3.21">
14154 Array class creation does not generate a class load event.
14155 </change>
14156 <change date="7 April 2004" version="0.3.22">
14157 Align thread state hierarchy more closely with java.lang.Thread.State.
14158 </change>
14159 <change date="12 April 2004" version="0.3.23">
14160 Clarify the documentation of thread state.
14161 </change>
14162 <change date="19 April 2004" version="0.3.24">
14163 Remove GarbageCollectionOccurred event -- can be done by agent.
14164 </change>
14165 <change date="22 April 2004" version="0.3.25">
14166 Define "command-line option".
14167 </change>
14168 <change date="29 April 2004" version="0.3.26">
14169 Describe the intended use of bytecode instrumentation.
14170 Fix description of extension event first parameter.
14171 </change>
14172 <change date="30 April 2004" version="0.3.27">
14173 Clarification and typos.
14174 </change>
14175 <change date="18 May 2004" version="0.3.28">
14176 Remove DataDumpRequest event.
14177 </change>
14178 <change date="18 May 2004" version="0.3.29">
14179 Clarify RawMonitorWait with zero timeout.
14180 Clarify thread state after RunAgentThread.
14181 </change>
14182 <change date="24 May 2004" version="0.3.30">
14183 Clean-up: fix bad/old links, etc.
14184 </change>
14185 <change date="30 May 2004" version="0.3.31">
14186 Clarifications including:
14187 All character strings are modified UTF-8.
14188 Agent thread visibiity.
14189 Meaning of obsolete method version.
14190 Thread invoking heap callbacks,
14191 </change>
14192 <change date="1 June 2004" version="1.0.32">
14193 Bump major.minor version numbers to "1.0".
14194 </change>
14195 <change date="2 June 2004" version="1.0.33">
14196 Clarify interaction between ForceGarbageCollection
14197 and ObjectFree.
14198 </change>
14199 <change date="6 June 2004" version="1.0.34">
14200 Restrict AddToBootstrapClassLoaderSearch and
14201 SetSystemProperty to the OnLoad phase only.
14202 </change>
14203 <change date="11 June 2004" version="1.0.35">
14204 Fix typo in SetTag.
14205 </change>
14206 <change date="18 June 2004" version="1.0.36">
14207 Fix trademarks.
14208 Add missing parameter in example GetThreadState usage.
14209 </change>
14210 <change date="4 August 2004" version="1.0.37">
14211 Copyright updates.
14212 </change>
14213 <change date="5 November 2004" version="1.0.38">
14214 Add missing function table layout.
14215 Add missing description of C++ member function format of functions.
14216 Clarify that name in CFLH can be NULL.
14217 Released as part of <tm>J2SE</tm> 5.0.
14218 </change>
14219 <change date="24 April 2005" version="1.1.47">
14220 Bump major.minor version numbers to "1.1".
14221 Add ForceEarlyReturn* functions.
14222 Add GetOwnedMonitorStackDepthInfo function.
14223 Add GetCurrentThread function.
14224 Add "since" version marker.
14225 Add AddToSystemClassLoaderSearch.
14226 Allow AddToBootstrapClassLoaderSearch be used in live phase.
14227 Fix historic rubbish in the descriptions of the heap_object_callback
14228 parameter of IterateOverHeap and IterateOverInstancesOfClass functions;
14229 disallow NULL for this parameter.
14230 Clarify, correct and make consistent: wording about current thread,
14231 opaque frames and insufficient number of frames in PopFrame.
14232 Consistently use "current frame" rather than "topmost".
14233 Clarify the JVMTI_ERROR_TYPE_MISMATCH errors in GetLocal* and SetLocal*
14234 by making them compatible with those in ForceEarlyReturn*.
14235 Many other clarifications and wording clean ups.
14236 </change>
14237 <change date="25 April 2005" version="1.1.48">
14238 Add GetConstantPool.
14239 Switch references to the first edition of the VM Spec, to the seconds edition.
14240 </change>
14241 <change date="26 April 2005" version="1.1.49">
14242 Clarify minor/major version order in GetConstantPool.
14243 </change>
14244 <change date="26 April 2005" version="1.1.50">
14245 Add SetNativeMethodPrefix and SetNativeMethodPrefixes.
14246 Reassign GetOwnedMonitorStackDepthInfo to position 153.
14247 Break out Class Loader Search in its own documentation category.
14248 Deal with overly long lines in XML source.
14249 </change>
14250 <change date="29 April 2005" version="1.1.51">
14251 Allow agents be started in the live phase.
14252 Added paragraph about deploying agents.
14253 </change>
14254 <change date="30 April 2005" version="1.1.52">
14255 Add specification description to SetNativeMethodPrefix(es).
14256 Better define the conditions on GetConstantPool.
14257 </change>
14258 <change date="30 April 2005" version="1.1.53">
14259 Break out the GetClassVersionNumber function from GetConstantPool.
14260 Clean-up the references to the VM Spec.
14261 </change>
14262 <change date="1 May 2005" version="1.1.54">
14263 Allow SetNativeMethodPrefix(es) in any phase.
14264 Add clarifications about the impact of redefinition on GetConstantPool.
14265 </change>
14266 <change date="2 May 2005" version="1.1.56">
14267 Various clarifications to SetNativeMethodPrefix(es).
14268 </change>
14269 <change date="2 May 2005" version="1.1.57">
14270 Add missing performance warning to the method entry event.
14271 </change>
14272 <change date="5 May 2005" version="1.1.58">
14273 Remove internal JVMDI support.
14274 </change>
14275 <change date="8 May 2005" version="1.1.59">
14276 Add <functionlink id="RetransformClasses"/>.
14277 Revamp the bytecode instrumentation documentation.
14278 Change <functionlink id="IsMethodObsolete"/> to no longer
14279 require the can_redefine_classes capability.
14280 </change>
14281 <change date="11 May 2005" version="1.1.63">
14282 Clarifications for retransformation.
14283 </change>
14284 <change date="11 May 2005" version="1.1.64">
14285 Clarifications for retransformation, per review.
14286 Lock "retransformation (in)capable" at class load enable time.
14287 </change>
14288 <change date="4 June 2005" version="1.1.67">
14289 Add new heap functionity which supports reporting primitive values,
14290 allows setting the referrer tag, and has more powerful filtering:
14291 FollowReferences, IterateThroughHeap, and their associated
14292 callbacks, structs, enums, and constants.
14293 </change>
14294 <change date="4 June 2005" version="1.1.68">
14295 Clarification.
14296 </change>
14297 <change date="6 June 2005" version="1.1.69">
14298 FollowReferences, IterateThroughHeap: Put callbacks in a struct;
14299 Add missing error codes; reduce bits in the visit control flags.
14300 </change>
14301 <change date="14 June 2005" version="1.1.70">
14302 More on new heap functionity: spec clean-up per review.
14303 </change>
14304 <change date="15 June 2005" version="1.1.71">
14305 More on new heap functionity: Rename old heap section to Heap (1.0).
14306 </change>
14307 <change date="21 June 2005" version="1.1.72">
14308 Fix typos.
14309 </change>
14310 <change date="27 June 2005" version="1.1.73">
14311 Make referrer info structure a union.
14312 </change>
14313 <change date="9 September 2005" version="1.1.74">
14314 In new heap functions:
14315 Add missing superclass reference kind.
14316 Use a single scheme for computing field indexes.
14317 Remove outdated references to struct based referrer info.
14318 </change>
14319 <change date="12 September 2005" version="1.1.75">
14320 Don't callback during FollowReferences on frivolous java.lang.Object superclass.
14321 </change>
14322 <change date="13 September 2005" version="1.1.76">
14323 In string primitive callback, length now Unicode length.
14324 In array and string primitive callbacks, value now "const".
14325 Note possible compiler impacts on setting JNI function table.
14326 </change>
14327 <change date="13 September 2005" version="1.1.77">
14328 GetClassVersionNumbers() and GetConstantPool() should return
14329 error on array or primitive class.
14330 </change>
14331 <change date="14 September 2005" version="1.1.78">
14332 Grammar fixes.
14333 </change>
14334 <change date="26 September 2005" version="1.1.79">
14335 Add IsModifiableClass query.
14336 </change>
14337 <change date="9 February 2006" version="1.1.81">
14338 Add referrer_class_tag parameter to jvmtiHeapReferenceCallback.
14339 </change>
14340 <change date="13 February 2006" version="1.1.82">
14341 Doc fixes: update can_redefine_any_class to include retransform.
14342 Clarify that exception events cover all Throwables.
14343 In GetStackTrace, no test is done for start_depth too big if start_depth is zero,
14344 Clarify fields reported in Primitive Field Callback -- static vs instance.
14345 Repair confusing names of heap types, including callback names.
14346 Require consistent usage of stack depth in the face of thread launch methods.
14347 Note incompatibility of <jvmti/> memory management with other systems.
14348 </change>
14349 <change date="14 February 2006" version="1.1.85">
14350 Fix typos and missing renames.
14351 </change>
14352 <change date="13 March 2006" version="1.1.86">
14353 Clarify that jmethodIDs and jfieldIDs can be saved.
14354 Clarify that Iterate Over Instances Of Class includes subclasses.
14355 </change>
14356 <change date="14 March 2006" version="1.1.87">
14357 Better phrasing.
14358 </change>
14359 <change date="16 March 2006" version="1.1.88">
14360 Match the referrer_index for static fields in Object Reference Callback
14361 with the Reference Implementation (and all other known implementations);
14362 that is, make it match the definition for instance fields.
14363 In GetThreadListStackTraces, add JVMTI_ERROR_INVALID_THREAD to cover
14364 an invalid thread in the list; and specify that not started threads
14365 return empty stacks.
14366 </change>
14367 <change date="17 March 2006" version="1.1.89">
14368 Typo.
14369 </change>
14370 <change date="25 March 2006" version="1.1.90">
14371 Typo.
14372 </change>
14373 <change date="6 April 2006" version="1.1.91">
14374 Remove restrictions on AddToBootstrapClassLoaderSearch and
14375 AddToSystemClassLoaderSearch.
14376 </change>
14377 <change date="1 May 2006" version="1.1.93">
14378 Changed spec to return -1 for monitor stack depth for the
14379 implementation which can not determine stack depth.
14380 </change>
14381 <change date="3 May 2006" version="1.1.94">
14382 Corrections for readability and accuracy courtesy of Alan Pratt of IBM.
14383 List the object relationships reported in FollowReferences.
14384 </change>
14385 <change date="5 May 2006" version="1.1.95">
14386 Clarify the object relationships reported in FollowReferences.
14387 </change>
14388 <change date="28 June 2006" version="1.1.98">
14389 Clarify DisposeEnvironment; add warning.
14390 Fix typos in SetLocalXXX "retrieve" => "set".
14391 Clarify that native method prefixes must remain set while used.
14392 Clarify that exactly one Agent_OnXXX is called per agent.
14393 Clarify that library loading is independent from start-up.
14394 Remove ambiguous reference to Agent_OnLoad in the Agent_OnUnload spec.
14395 </change>
14396 <change date="31 July 2006" version="1.1.99">
14397 Clarify the interaction between functions and exceptions.
14398 Clarify and give examples of field indices.
14399 Remove confusing "That is" sentence from MonitorWait and MonitorWaited events.
14400 Update links to point to Java 6.
14401 </change>
14402 <change date="6 August 2006" version="1.1.102">
14403 Add ResourceExhaustedEvent.
14404 </change>
14405 <change date="11 October 2012" version="1.2.2">
14406 Fixed the "HTTP" and "Missing Anchor" errors reported by the LinkCheck tool.
14407 </change>
14408 <change date="19 June 2013" version="1.2.3">
14409 Added support for statically linked agents.
14410 </change>
14411 <change date="20 January 2016" version="9.0.0">
14412 Support for modules:
14413 - The majorversion is 9 now
14414 - The ClassFileLoadHook events are not sent during the primordial phase anymore.
14415 - Add new function GetAllModules
14416 </change>
14417 <change date="17 February 2016" version="9.0.0">
14418 Support for modules:
14419 - Add new capability can_generate_early_vmstart
14420 - Allow CompiledMethodLoad events at start phase
14421 </change>
14422 </changehistory>
14423
14424 </specification>
14425 <!-- Keep this comment at the end of the file
14426 Local variables:
14427 mode: sgml
14428 sgml-omittag:t
14429 sgml-shorttag:t
14430 sgml-namecase-general:t
14431 sgml-general-insert-case:lower
14432 sgml-minimize-attributes:nil
14433 sgml-always-quote-attributes:t
14434 sgml-indent-step:2
14435 sgml-indent-data:t
14436 sgml-parent-document:nil
14437 sgml-exposed-tags:nil
14438 sgml-local-catalogs:nil
14439 sgml-local-ecat-files:nil
14440 End:
14441 -->