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26
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356 ]>
357
358 <specification label="JVM(TM) Tool Interface"
359 majorversion="1"
360 minorversion="2"
361 microversion="3">
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 startup as it would
462 have called the dynamic entry point Agent_OnUnLoad.
463 If a <i>statically linked</i> agent L exports a function called
464 Agent_OnUnLoad_L and a function called Agent_OnUnLoad, the Agent_OnUnLoad
465 function will be ignored.
466 <p/>
467 If an agent L is <i>statically linked</i>, an Agent_OnAttach_L function
468 will be invoked with the same arguments and expected return value as
469 specified for the Agent_OnAttach function.
470 If a <i>statically linked</i> agent L exports a function called
471 Agent_OnAttach_L and a function called Agent_OnAttach, the Agent_OnAttach
472 function will be ignored.
473 </intro>
474
475 <intro id="starting" label="Agent Command Line Options">
476 The term "command-line option" is used below to
477 mean options supplied in the <code>JavaVMInitArgs</code> argument
478 to the <code>JNI_CreateJavaVM</code> function of the JNI
479 Invocation API.
480 <p/>
481 One of the two following
482 command-line options is used on VM startup to
483 properly load and run agents.
484 These arguments identify the library containing
485 the agent as well as an options
486 string to be passed in at startup.
487 <dl>
488 <dt><code>-agentlib:</code><i><agent-lib-name></i><code>=</code><i><options></i></dt>
489 <dd>
490 The name following <code>-agentlib:</code> is the name of the
491 library to load. Lookup of the library, both its full name and location,
492 proceeds in a platform-specific manner.
493 Typically, the <i><agent-lib-name></i> is expanded to an
494 operating system specific file name.
495 The <i><options></i> will be passed to the agent on start-up.
496 For example, if the option
497 <code>-agentlib:foo=opt1,opt2</code> is specified, the VM will attempt to
498 load the shared library <code>foo.dll</code> from the system <code>PATH</code>
499 under <tm>Windows</tm> or <code>libfoo.so</code> from the
500 <code>LD_LIBRARY_PATH</code> under the <tm>Solaris</tm> operating
501 environment.
502 If the agent library is statically linked into the executable
503 then no actual loading takes place.
504 <p/>
505 </dd>
506 <dt><code>-agentpath:</code><i><path-to-agent></i><code>=</code><i><options></i></dt>
507 <dd>
508 The path following <code>-agentpath:</code> is the absolute path from which
509 to load the library.
510 No library name expansion will occur.
511 The <i><options></i> will be passed to the agent on start-up.
512 For example, if the option
513 <code>-agentpath:c:\myLibs\foo.dll=opt1,opt2</code> is specified, the VM will attempt to
514 load the shared library <code>c:\myLibs\foo.dll</code>. If the agent
515 library is statically linked into the executable
516 then no actual loading takes place.
517 <p/>
518 </dd>
519 </dl>
520 For a dynamic shared library agent, the start-up routine
521 <internallink id="onload"><code>Agent_OnLoad</code></internallink>
522 in the library will be invoked. If the agent library is statically linked
523 into the executable then the system will attempt to invoke the
524 <code>Agent_OnLoad_<agent-lib-name></code> entry point where
525 <agent-lib-name> is the basename of the
526 agent. In the above example <code>-agentpath:c:\myLibs\foo.dll=opt1,opt2</code>,
527 the system will attempt to find and call the <code>Agent_OnLoad_foo</code> start-up routine.
528 <p/>
529 Libraries loaded with <code>-agentlib:</code> or <code>-agentpath:</code>
530 will be searched for JNI native method implementations to facilitate the
531 use of Java programming language code in tools, as is needed for
532 <internallink id="bci">bytecode instrumentation</internallink>.
533 <p/>
534 The agent libraries will be searched after all other libraries have been
535 searched (agents wishing to override or intercept the native method
536 implementations of non-agent methods can use the
537 <eventlink id="NativeMethodBind">NativeMethodBind event</eventlink>).
538 <p/>
539 These switches do the above and nothing more - they do not change the
540 state of the VM or <jvmti/>. No command line options are needed
541 to enable <jvmti/>
542 or aspects of <jvmti/>, this is handled programmatically
543 by the use of
544 <internallink id="capability">capabilities</internallink>.
545 </intro>
546
547 <intro id="startup" label="Agent Start-Up">
548 The VM starts each agent by invoking a start-up function.
549 If the agent is started in the <code>OnLoad</code>
550 <functionlink id="GetPhase">phase</functionlink> the function
551 <internallink id="onload"><code>Agent_OnLoad</code></internallink>
552 or <internallink id="onload"><code>Agent_OnLoad_L</code></internallink>
553 for statically linked agents will be invoked.
554 If the agent is started in the live
555 <functionlink id="GetPhase">phase</functionlink> the function
556 <internallink id="onattach"><code>Agent_OnAttach</code></internallink>
557 or <internallink id="onattach"><code>Agent_OnAttach_L</code></internallink>
558 for statically linked agents will be invoked.
559 Exactly one call to a start-up function is made per agent.
560 </intro>
561
562 <intro id="onload" label="Agent Start-Up (OnLoad phase)">
563 If an agent is started during the <code>OnLoad</code> phase then its
564 agent library must export a start-up function with the following prototype:
565 <example>
566 JNIEXPORT jint JNICALL
567 Agent_OnLoad(JavaVM *vm, char *options, void *reserved)</example>
568 Or for a statically linked agent named 'L':
569 <example>
570 JNIEXPORT jint JNICALL
571 Agent_OnLoad_L(JavaVM *vm, char *options, void *reserved)</example>
572
573 The VM will start the agent by calling this function.
574 It will be called early enough in VM initialization that:
575 <ul>
576 <li><functionlink id="SetSystemProperty">system properties</functionlink>
577 may be set before they have been used in the start-up of the VM</li>
578 <li>the full set of
579 <internallink id="capability">capabilities</internallink>
580 is still available (note that capabilities that configure the VM
581 may only be available at this time--see the
582 <internallink id="capability">Capability function section</internallink>)</li>
583 <li>no bytecodes have executed</li>
584 <li>no classes have been loaded</li>
585 <li>no objects have been created</li>
586 </ul>
587 <p/>
588 The VM will call the <code>Agent_OnLoad</code> or
589 <code>Agent_OnLoad_<agent-lib-name></code> function with
590 <i><options></i> as the second argument -
591 that is, using the command-line option examples,
592 <code>"opt1,opt2"</code> will be passed to the <code>char *options</code>
593 argument of <code>Agent_OnLoad</code>.
594 The <code>options</code> argument is encoded as a
595 <internallink id="mUTF">modified UTF-8</internallink> string.
596 If <i>=<options></i> is not specified,
597 a zero length string is passed to <code>options</code>.
598 The lifespan of the <code>options</code> string is the
599 <code>Agent_OnLoad</code> or <code>Agent_OnLoad_<agent-lib-name></code>
600 call. If needed beyond this time the string or parts of the string must
601 be copied.
602 The period between when <code>Agent_OnLoad</code> is called and when it
603 returns is called the <i>OnLoad phase</i>.
604 Since the VM is not initialized during the OnLoad
605 <functionlink id="GetPhase">phase</functionlink>,
606 the set of allowed operations
607 inside <code>Agent_OnLoad</code> is restricted (see the function descriptions for the
608 functionality available at this time).
609 The agent can safely process the options and set
610 event callbacks with <functionlink id="SetEventCallbacks"></functionlink>. Once
611 the VM initialization event is received
612 (that is, the <eventlink id="VMInit">VMInit</eventlink>
613 callback is invoked), the agent
614 can complete its initialization.
615 <rationale>
616 Early startup is required so that agents can set the desired capabilities,
617 many of which must be set before the VM is initialized.
618 In JVMDI, the -Xdebug command-line option provided
619 very coarse-grain control of capabilities.
620 JVMPI implementations use various tricks to provide a single "JVMPI on" switch.
621 No reasonable command-line
622 option could provide the fine-grain of control required to balance needed capabilities vs
623 performance impact.
624 Early startup is also needed so that agents can control the execution
625 environment - modifying the file system and system properties to install
626 their functionality.
627 </rationale>
628 <p/>
629 The return value from <code>Agent_OnLoad</code> or
630 <code>Agent_OnLoad_<agent-lib-name></code> is used to indicate an error.
631 Any value other than zero indicates an error and causes termination of the VM.
632 </intro>
633
634 <intro id="onattach" label="Agent Start-Up (Live phase)">
635 A VM may support a mechanism that allows agents to be started in the VM during the live
636 <functionlink id="GetPhase">phase</functionlink>. The details of how this is supported,
637 are implementation specific. For example, a tool may use some platform specific mechanism,
638 or implementation specific API, to attach to the running VM, and request it start a given
639 agent.
640 <p/>
641 If an agent is started during the live phase then its agent library
642 must export a start-up function
643 with the following prototype:
644 <example>
645 JNIEXPORT jint JNICALL
646 Agent_OnAttach(JavaVM* vm, char *options, void *reserved)</example>
647 Or for a statically linked agent named 'L':
648 <example>
649 JNIEXPORT jint JNICALL
650 Agent_OnAttach_L(JavaVM* vm, char *options, void *reserved)</example>
651
652 <p/>
653 The VM will start the agent by calling this function.
654 It will be called in the context of a thread
655 that is attached to the VM. The first argument <i><vm></i> is the Java VM.
656 The <i><options></i> argument is the startup options provided to the agent.
657 <i><options></i> is encoded as a <internallink id="mUTF">modified UTF-8
658 </internallink> string.
659 If startup options were not provided, a zero length string is passed to
660 <code>options</code>. The lifespan of the <code>options</code> string is the
661 <code>Agent_OnAttach</code> or <code>Agent_OnAttach_<agent-lib-name></code> call.
662 If needed beyond this time the string or parts of the string must be copied.
663 <p/>
664 Note that some <internallink id="capability">capabilities</internallink>
665 may not be available in the live phase.
666 <p/>
667 The <code>Agent_OnAttach</code> or <code>Agent_OnAttach_<agent-lib-name
668 ></code> function initializes the agent and returns a value
669 to the VM to indicate if an error occurred. Any value other than zero indicates an error.
670 An error does not cause the VM to terminate. Instead the VM ignores the error, or takes
671 some implementation specific action -- for example it might print an error to standard error,
672 or record the error in a system log.
673 </intro>
674
675 <intro id="onunload" label="Agent Shutdown">
676 The library may optionally export a
677 shutdown function with the following prototype:
678 <example>
679 JNIEXPORT void JNICALL
680 Agent_OnUnload(JavaVM *vm)</example>
681 Or for a statically linked agent named 'L':
682 <example>
683 JNIEXPORT void JNICALL
684 Agent_OnUnload_L(JavaVM *vm)</example>
685
686 This function will be called by the VM when the library is about to be unloaded.
687 The library will be unloaded (unless it is statically linked into the
688 executable) and this function will be called if some platform specific
689 mechanism causes the unload (an unload mechanism is not specified in this document)
690 or the library is (in effect) unloaded by the termination of the VM whether through
691 normal termination or VM failure, including start-up failure.
692 Uncontrolled shutdown is, of couse, an exception to this rule.
693 Note the distinction between this function and the
694 <eventlink id="VMDeath">VM Death event</eventlink>: for the VM Death event
695 to be sent, the VM must have run at least to the point of initialization and a valid
696 <jvmti/> environment must exist which has set a callback for VMDeath
697 and enabled the event.
698 None of these are required for <code>Agent_OnUnload</code> or
699 <code>Agent_OnUnload_<agent-lib-name></code> and this function
700 is also called if the library is unloaded for other reasons.
701 In the case that a VM Death event is sent, it will be sent before this
702 function is called (assuming this function is called due to VM termination).
703 This function can be used to clean-up resources allocated by the agent.
704 </intro>
705
706 <intro id="tooloptions" label="JAVA_TOOL_OPTIONS">
707 Since the command-line cannot always be accessed or modified, for example in embedded VMs
708 or simply VMs launched deep within scripts, a <code>JAVA_TOOL_OPTIONS</code> variable is
709 provided so that agents may be launched in these cases.
710 <p/>
711 Platforms which support environment variables or other named strings, may support the
712 <code>JAVA_TOOL_OPTIONS</code> variable. This variable will be broken into options at white-space
713 boundaries. White-space characters include space, tab, carriage-return, new-line,
714 vertical-tab, and form-feed. Sequences of white-space characters are considered
715 equivalent to a single white-space character. No white-space is included in the options
716 unless quoted. Quoting is as follows:
717 <ul>
718 <li>All characters enclosed between a pair of single quote marks (''), except a single
719 quote, are quoted.</li>
720 <li>Double quote characters have no special meaning inside a pair of single quote marks.</li>
721 <li>All characters enclosed between a pair of double quote marks (""), except a double
722 quote, are quoted.</li>
723 <li>Single quote characters have no special meaning inside a pair of double quote marks.</li>
724 <li>A quoted part can start or end anywhere in the variable.</li>
725 <li>White-space characters have no special meaning when quoted -- they are included in
726 the option like any other character and do not mark white-space boundaries.</li>
727 <li>The pair of quote marks is not included in the option.</li>
728 </ul>
729 <code>JNI_CreateJavaVM</code> (in the JNI Invocation API) will prepend these options to the options supplied
730 in its <code>JavaVMInitArgs</code> argument. Platforms may disable this feature in cases where security is
731 a concern; for example, the Reference Implementation disables this feature on Unix systems when
732 the effective user or group ID differs from the real ID.
733 This feature is intended to support the initialization of tools -- specifically including the
734 launching of native or Java programming language agents. Multiple tools may wish to use this
735 feature, so the variable should not be overwritten, instead, options should be appended to
736 the variable. Note that since the variable is processed at the time of the JNI Invocation
737 API create VM call, options processed by a launcher (e.g., VM selection options) will not be handled.
738 </intro>
739
740 <intro id="environments" label="Environments">
741 The <jvmti/> specification supports the use of multiple simultaneous
742 <jvmti/> agents.
743 Each agent has its own <jvmti/> environment.
744 That is, the <jvmti/> state is
745 separate for each agent - changes to one environment do not affect the
746 others. The state of a <jvmti/>
747 environment includes:
748 <ul>
749 <li><functionlink id="SetEventCallbacks">the event callbacks</functionlink></li>
750 <li><functionlink id="SetEventNotificationMode">the set of events which are enabled</functionlink></li>
751 <li><internallink id="capability">the capabilities</internallink></li>
752 <li><internallink id="memory">the memory allocation/deallocation hooks</internallink></li>
753 </ul>
754 Although their <jvmti/> state
755 is separate, agents inspect and modify the shared state
756 of the VM, they also share the native environment in which they execute.
757 As such, an agent can perturb the results of other agents or cause them
758 to fail. It is the responsibility of the agent writer to specify the level
759 of compatibility with other agents. <jvmti/> implementations are not capable
760 of preventing destructive interactions between agents. Techniques to reduce
761 the likelihood of these occurrences are beyond the scope of this document.
762 <p/>
763 An agent creates a <jvmti/> environment
764 by passing a <jvmti/> version
765 as the interface ID to the JNI Invocation API function
766 <externallink id="http://docs.oracle.com/javase/7/docs/technotes/guides/jni/spec/invocation.html#GetEnv"><code>GetEnv</code></externallink>.
767 See <internallink id="jvmtiEnvAccess">Accessing <jvmti/> Functions</internallink>
768 for more details on the creation and use of
769 <jvmti/> environments.
770 Typically, <jvmti/> environments are created by calling <code>GetEnv</code> from
771 <internallink id="onload"><code>Agent_OnLoad</code></internallink>.
772 </intro>
773
774 <intro id="bci" label="Bytecode Instrumentation">
775 This interface does not include some events that one might expect in an interface with
776 profiling support. Some examples include object allocation events and full speed
777 method enter and exit events. The interface instead provides support for
778 <i>bytecode instrumentation</i>, the ability to alter the Java virtual machine
779 bytecode instructions which comprise the target program. Typically, these alterations
780 are to add "events" to the code of a method - for example, to add, at the beginning of a method,
781 a call to <code>MyProfiler.methodEntered()</code>.
782 Since the changes are purely additive, they do not modify application
783 state or behavior.
784 Because the inserted agent code is standard bytecodes, the VM can run at full speed,
785 optimizing not only the target program but also the instrumentation. If the
786 instrumentation does not involve switching from bytecode execution, no expensive
787 state transitions are needed. The result is high performance events.
788 This approach also provides complete control to the agent: instrumentation can be
789 restricted to "interesting" portions of the code (e.g., the end user's code) and
790 can be conditional. Instrumentation can run entirely in Java programming language
791 code or can call into the native agent. Instrumentation can simply maintain
792 counters or can statistically sample events.
793 <p/>
794 Instrumentation can be inserted in one of three ways:
795 <ul>
796 <li>
797 Static Instrumentation: The class file is instrumented before it
798 is loaded into the VM - for example, by creating a duplicate directory of
799 <code>*.class</code> files which have been modified to add the instrumentation.
800 This method is extremely awkward and, in general, an agent cannot know
801 the origin of the class files which will be loaded.
802 </li>
803 <li>
804 Load-Time Instrumentation: When a class file is loaded by the VM, the raw
805 bytes of the class file are sent for instrumentation to the agent.
806 The <eventlink id="ClassFileLoadHook"/>
807 event, triggered by the class load,
808 provides this functionality. This mechanism provides efficient
809 and complete access to one-time instrumentation.
810 </li>
811 <li>
812 Dynamic Instrumentation: A class which is already loaded (and possibly
813 even running) is modified. This optional feature is provided by the
814 <eventlink id="ClassFileLoadHook"/> event, triggered by calling the
815 <functionlink id="RetransformClasses"/> function.
816 Classes can be modified multiple times and can be returned to their
817 original state.
818 The mechanism allows instrumentation which changes during the
819 course of execution.
820 </li>
821 </ul>
822 <p/>
823 The class modification functionality provided in this interface
824 is intended to provide a mechanism for instrumentation
825 (the <eventlink id="ClassFileLoadHook"/> event
826 and the <functionlink id="RetransformClasses"/> function)
827 and, during development, for fix-and-continue debugging
828 (the <functionlink id="RedefineClasses"/> function).
829 <p/>
830 Care must be taken to avoid perturbing dependencies, especially when
831 instrumenting core classes. For example, an approach to getting notification
832 of every object allocation is to instrument the constructor on
833 <code>Object</code>. Assuming that the constructor is initially
834 empty, the constructor could be changed to:
835 <example>
836 public Object() {
837 MyProfiler.allocationTracker(this);
838 }
839 </example>
840 However, if this change was made using the
841 <eventlink id="ClassFileLoadHook"/>
842 event then this might impact a typical VM as follows:
843 the first created object will call the constructor causing a class load of
844 <code>MyProfiler</code>; which will then cause
845 object creation, and since <code>MyProfiler</code> isn't loaded yet,
846 infinite recursion; resulting in a stack overflow. A refinement of this
847 would be to delay invoking the tracking method until a safe time. For
848 example, <code>trackAllocations</code> could be set in the
849 handler for the <code>VMInit</code> event.
850 <example>
851 static boolean trackAllocations = false;
852
853 public Object() {
854 if (trackAllocations) {
855 MyProfiler.allocationTracker(this);
856 }
857 }
858 </example>
859 <p/>
860 The <functionlink id="SetNativeMethodPrefix"/> allows native methods
861 to be instrumented by the use of wrapper methods.
862 </intro>
863
864 <intro id="mUTF" label="Modified UTF-8 String Encoding">
865 <jvmti/> uses modified UTF-8 to encode character strings.
866 This is the same encoding used by JNI.
867 Modified UTF-8 differs
868 from standard UTF-8 in the representation of supplementary characters
869 and of the null character. See the
870 <externallink id="http://docs.oracle.com/javase/7/docs/technotes/guides/jni/spec/types.html#wp16542">
871 Modified UTF-8 Strings</externallink>
872 section of the JNI specification for details.
873 </intro>
874
875 <intro id="context" label="Specification Context">
876 Since this interface provides access to the state of applications running in the
877 Java virtual machine;
878 terminology refers to the Java platform and not the native
879 platform (unless stated otherwise). For example:
880 <ul>
881 <li>"thread" means Java programming language thread.</li>
882 <li>"stack frame" means Java virtual machine stack frame.</li>
883 <li>"class" means Java programming language class.</li>
884 <li>"heap" means Java virtual machine heap.</li>
885 <li>"monitor" means Java programming language object monitor.</li>
886 </ul>
887 <p/>
888 Sun, Sun Microsystems, the Sun logo, Java, and JVM
889 are trademarks or registered trademarks of Oracle
890 and/or its affiliates, in the U.S. and other countries.
891 </intro>
892
893
894 <functionsection label="Functions">
895 <intro id="jvmtiEnvAccess" label="Accessing Functions">
896 Native code accesses <jvmti/> features
897 by calling <jvmti/> functions.
898 Access to <jvmti/> functions is by use of an interface pointer
899 in the same manner as
900 <externallink id="http://docs.oracle.com/javase/7/docs/technotes/guides/jni/spec/design.html">Java
901 Native Interface (JNI) functions</externallink> are accessed.
902 The <jvmti/> interface pointer is called the
903 <i>environment pointer</i>.
904 <p/>
905 An environment pointer is a pointer to an environment and has
906 the type <code>jvmtiEnv*</code>.
907 An environment has information about its <jvmti/> connection.
908 The first value in the environment is a pointer to the function table.
909 The function table is an array of pointers to <jvmti/> functions.
910 Every function pointer is at a predefined offset inside the
911 array.
912 <p/>
913 When used from the C language:
914 double indirection is used to access the functions;
915 the environment pointer provides context and is the first
916 parameter of each function call; for example:
917 <example>
918 jvmtiEnv *jvmti;
919 ...
920 jvmtiError err = (*jvmti)->GetLoadedClasses(jvmti, &class_count, &classes);
921 </example>
922 <p/>
923 When used from the C++ language:
924 functions are accessed as member functions of <code>jvmtiEnv</code>;
925 the environment pointer is not passed to the function call; for example:
926 <example>
927 jvmtiEnv *jvmti;
928 ...
929 jvmtiError err = jvmti->GetLoadedClasses(&class_count, &classes);
930 </example>
931 Unless otherwise stated, all examples and declarations in this
932 specification use the C language.
933 <p/>
934 A <jvmti/> environment can be obtained through the JNI Invocation API
935 <code>GetEnv</code> function:
936 <example>
937 jvmtiEnv *jvmti;
938 ...
939 (*jvm)->GetEnv(jvm, &jvmti, JVMTI_VERSION_1_0);
940 </example>
941 Each call to <code>GetEnv</code>
942 creates a new <jvmti/> connection and thus
943 a new <jvmti/> environment.
944 The <code>version</code> argument of <code>GetEnv</code> must be
945 a <jvmti/> version.
946 The returned environment may have a different version than the
947 requested version but the returned environment must be compatible.
948 <code>GetEnv</code> will return <code>JNI_EVERSION</code> if a
949 compatible version is not available, if <jvmti/> is not supported or
950 <jvmti/> is not supported in the current VM configuration.
951 Other interfaces may be added for creating <jvmti/> environments
952 in specific contexts.
953 Each environment has its own state (for example,
954 <functionlink id="SetEventNotificationMode">desired events</functionlink>,
955 <functionlink id="SetEventCallbacks">event handling functions</functionlink>, and
956 <functionlink id="AddCapabilities">capabilities</functionlink>).
957 An environment is released with
958 <functionlink id="DisposeEnvironment"></functionlink>.
959 Thus, unlike JNI which has one environment per thread, <jvmti/> environments work
960 across threads and are created dynamically.
961 </intro>
962
963 <intro id="functionReturn" label="Function Return Values">
964 <jvmti/> functions always return an
965 <internallink id="ErrorSection">error code</internallink> via the
966 <datalink id="jvmtiError"/> function return value.
967 Some functions can return additional
968 values through pointers provided by the calling function.
969 In some cases, <jvmti/> functions allocate memory that your program must
970 explicitly deallocate. This is indicated in the individual <jvmti/>
971 function descriptions. Empty lists, arrays, sequences, etc are
972 returned as <code>NULL</code>.
973 <p/>
974 In the event that the <jvmti/> function encounters
975 an error (any return value other than <code>JVMTI_ERROR_NONE</code>) the values
976 of memory referenced by argument pointers is undefined, but no memory
977 will have been allocated and no global references will have been allocated.
978 If the error occurs because of invalid input, no action will have occurred.
979 </intro>
980
981 <intro id="refs" label="Managing JNI Object References">
982 <jvmti/> functions identify objects with JNI references
983 (<datalink id="jobject"/> and <datalink id="jclass"/>)
984 and their derivatives
985 (<datalink id="jthread"/> and <datalink id="jthreadGroup"/>).
986 References passed to
987 <jvmti/> functions can be either global or local, but they must be
988 strong references. All references returned by <jvmti/> functions are
989 local references--these local references are created
990 during the <jvmti/> call.
991 Local references are a resource that must be managed (see the
992 <externallink id="http://docs.oracle.com/javase/7/docs/technotes/guides/jni/spec/functions.html#wp18654">JNI Documentation</externallink>).
993 When threads return from native code all local references
994 are freed. Note that some threads, including typical
995 agent threads, will never return from native code.
996 A thread is ensured the ability to create sixteen local
997 references without the need for any explicit management.
998 For threads executing a limited number of <jvmti/> calls before
999 returning from native code
1000 (for example, threads processing events),
1001 it may be determined that no explicit management
1002 is needed.
1003 However, long running agent threads will need explicit
1004 local reference management--usually with the JNI functions
1005 <code>PushLocalFrame</code> and <code>PopLocalFrame</code>.
1006 Conversely, to preserve references beyond the
1007 return from native code, they must be converted to global references.
1008 These rules do not apply to <datalink id="jmethodID"/> and <datalink id="jfieldID"/>
1009 as they are not <datalink id="jobject"/>s.
1010 </intro>
1011
1012 <intro id="prereqState" label="Prerequisite State for Calling Functions">
1013 Unless the function explicitly states that the agent must bring
1014 a thread or the VM to a particular state (for example, suspended),
1015 the <jvmti/> implementation is responsible for bringing the VM to a
1016 safe and consistent state for performing the function.
1017 </intro>
1018
1019 <intro id="functionsExceptions" label="Exceptions and Functions">
1020 <jvmti/> functions never throw exceptions; error conditions are
1021 communicated via the
1022 <internallink id="functionReturn">function return value</internallink>.
1023 Any existing exception state is preserved across a call to a
1024 <jvmti/> function.
1025 See the
1026 <externallink
1027 id="http://docs.oracle.com/javase/7/docs/technotes/guides/jni/spec/design.html#wp770"
1028 >Java Exceptions</externallink>
1029 section of the JNI specification for information on handling exceptions.
1030 </intro>
1031
1032 <category id="memory" label="Memory Management">
1033 <intro>
1034 These functions provide for the allocation and deallocation of
1035 memory used by <jvmti/> functionality and can be used to provide
1036 working memory for agents.
1037 Memory managed by <jvmti/> is not compatible with other memory
1038 allocation libraries and mechanisms.
1039 </intro>
1040
1041 <function id="Allocate" jkernel="yes" phase="any" callbacksafe="safe" impl="notrace" num="46">
1042 <synopsis>Allocate</synopsis>
1043 <description>
1044 Allocate an area of memory through the <jvmti/> allocator.
1045 The allocated
1046 memory should be freed with <functionlink id="Deallocate"></functionlink>.
1047 </description>
1048 <origin>jvmdi</origin>
1049 <capabilities>
1050 </capabilities>
1051 <parameters>
1052 <param id="size">
1053 <jlong/>
1054 <description>
1055 The number of bytes to allocate.
1056 <rationale>
1057 <code>jlong</code> is used for compatibility with JVMDI.
1058 </rationale>
1059 </description>
1060 </param>
1061 <param id="mem_ptr">
1062 <allocbuf incount="size"><uchar/></allocbuf>
1063 <description>
1064 On return, a pointer to the beginning of the allocated memory.
1065 If <code>size</code> is zero, <code>NULL</code> is returned.
1066 </description>
1067 </param>
1068 </parameters>
1069 <errors>
1070 <error id="JVMTI_ERROR_OUT_OF_MEMORY">
1071 Memory request cannot be honored.
1072 </error>
1073 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
1074 <paramlink id="size"></paramlink> is less than zero.
1075 </error>
1076 </errors>
1077 </function>
1078
1079 <function id="Deallocate" jkernel="yes" phase="any" callbacksafe="safe" impl="notrace" num="47">
1080 <synopsis>Deallocate</synopsis>
1081 <description>
1082 Deallocate <code>mem</code> using the <jvmti/> allocator.
1083 This function should
1084 be used to deallocate any memory allocated and returned
1085 by a <jvmti/> function
1086 (including memory allocated with <functionlink id="Allocate"></functionlink>).
1087 All allocated memory must be deallocated
1088 or the memory cannot be reclaimed.
1089 </description>
1090 <origin>jvmdi</origin>
1091 <capabilities>
1092 </capabilities>
1093 <parameters>
1094 <param id="mem">
1095 <outbuf>
1096 <uchar/>
1097 <nullok>the call is ignored</nullok>
1098 </outbuf>
1099 <description>
1100 A pointer to the beginning of the allocated memory.
1101 Please ignore "On return, the elements are set."
1102 <todo>keep it from generating "On return, the elements are set"</todo>
1103 </description>
1104 </param>
1105 </parameters>
1106 <errors>
1107 </errors>
1108 </function>
1109 </category>
1110
1111 <category id="threadCategory" label="Thread">
1112 <intro>
1113 </intro>
1114
1115 <function id="GetThreadState" num="17">
1116 <synopsis>Get Thread State</synopsis>
1117 <description>
1118 Get the state of a thread. The state of the thread is represented by the
1119 answers to the hierarchical set of questions below:
1120 <ul type="circle">
1121 <li><i>Alive?</i>
1122 <ul>
1123 <li>Not alive.
1124 <ul type="circle">
1125 <li><i>Why not alive?</i>
1126 <ul>
1127 <li>New.</li>
1128 <li>Terminated (<datalink
1129 id="JVMTI_THREAD_STATE_TERMINATED"><code>JVMTI_THREAD_STATE_TERMINATED</code></datalink>)</li>
1130 </ul>
1131 </li>
1132 </ul>
1133 </li>
1134 <li>Alive (<datalink
1135 id="JVMTI_THREAD_STATE_ALIVE"><code>JVMTI_THREAD_STATE_ALIVE</code></datalink>)
1136 <ul type="circle">
1137 <li><i>Suspended?</i>
1138 <ul>
1139 <li>Suspended (<datalink
1140 id="JVMTI_THREAD_STATE_SUSPENDED"><code>JVMTI_THREAD_STATE_SUSPENDED</code></datalink>)</li>
1141 <li>Not suspended</li>
1142 </ul>
1143 </li>
1144 <li><i>Interrupted?</i>
1145 <ul>
1146 <li>Interrupted (<datalink
1147 id="JVMTI_THREAD_STATE_INTERRUPTED"><code>JVMTI_THREAD_STATE_INTERRUPTED</code></datalink>)</li>
1148 <li>Not interrupted.</li>
1149 </ul>
1150 </li>
1151 <li><i>In native?</i>
1152 <ul>
1153 <li>In native code (<datalink
1154 id="JVMTI_THREAD_STATE_IN_NATIVE"><code>JVMTI_THREAD_STATE_IN_NATIVE</code></datalink>)</li>
1155 <li>In Java programming language code</li>
1156 </ul>
1157 </li>
1158 <li><i>What alive state?</i>
1159 <ul>
1160 <li>Runnable (<datalink
1161 id="JVMTI_THREAD_STATE_RUNNABLE"><code>JVMTI_THREAD_STATE_RUNNABLE</code></datalink>)</li>
1162 <li>Blocked (<datalink
1163 id="JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER"><code>JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER</code></datalink>)</li>
1164 <li>Waiting (<datalink
1165 id="JVMTI_THREAD_STATE_WAITING"><code>JVMTI_THREAD_STATE_WAITING</code></datalink>)
1166 <ul type="circle">
1167 <li><i>Timed wait?</i>
1168 <ul>
1169 <li>Indefinite (<datalink
1170 id="JVMTI_THREAD_STATE_WAITING_INDEFINITELY"><code>JVMTI_THREAD_STATE_WAITING_INDEFINITELY</code></datalink></li>
1171 <li>Timed (<datalink
1172 id="JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT"><code>JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT</code></datalink>)</li>
1173 </ul>
1174 </li>
1175 <li><i>Why waiting?</i>
1176 <ul>
1177 <li>Object.wait (<datalink
1178 id="JVMTI_THREAD_STATE_IN_OBJECT_WAIT"><code>JVMTI_THREAD_STATE_IN_OBJECT_WAIT</code></datalink>)</li>
1179 <li>LockSupport.park (<datalink
1180 id="JVMTI_THREAD_STATE_PARKED"><code>JVMTI_THREAD_STATE_PARKED</code></datalink>)</li>
1181 <li>Sleeping (<datalink
1182 id="JVMTI_THREAD_STATE_SLEEPING"><code>JVMTI_THREAD_STATE_SLEEPING</code></datalink>)</li>
1183 </ul>
1184 </li>
1185 </ul>
1186 </li>
1187 </ul>
1188 </li>
1189 </ul>
1190 </li>
1191 </ul>
1192 </li>
1193 </ul>
1194 <p/>
1195 The answers are represented by the following bit vector.
1196 <constants id="jvmtiThreadState" label="Thread State Flags" kind="bits">
1197 <constant id="JVMTI_THREAD_STATE_ALIVE" num="0x0001">
1198 Thread is alive. Zero if thread is new (not started) or terminated.
1199 </constant>
1200 <constant id="JVMTI_THREAD_STATE_TERMINATED" num="0x0002">
1201 Thread has completed execution.
1202 </constant>
1203 <constant id="JVMTI_THREAD_STATE_RUNNABLE" num="0x0004">
1204 Thread is runnable.
1205 </constant>
1206 <constant id="JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER" num="0x0400">
1207 Thread is waiting to enter a synchronization block/method or,
1208 after an <code>Object.wait()</code>, waiting to re-enter a
1209 synchronization block/method.
1210 </constant>
1211 <constant id="JVMTI_THREAD_STATE_WAITING" num="0x0080">
1212 Thread is waiting.
1213 </constant>
1214 <constant id="JVMTI_THREAD_STATE_WAITING_INDEFINITELY" num="0x0010">
1215 Thread is waiting without a timeout.
1216 For example, <code>Object.wait()</code>.
1217 </constant>
1218 <constant id="JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT" num="0x0020">
1219 Thread is waiting with a maximum time to wait specified.
1220 For example, <code>Object.wait(long)</code>.
1221 </constant>
1222 <constant id="JVMTI_THREAD_STATE_SLEEPING" num="0x0040">
1223 Thread is sleeping -- <code>Thread.sleep(long)</code>.
1224 </constant>
1225 <constant id="JVMTI_THREAD_STATE_IN_OBJECT_WAIT" num="0x0100">
1226 Thread is waiting on an object monitor -- <code>Object.wait</code>.
1227 </constant>
1228 <constant id="JVMTI_THREAD_STATE_PARKED" num="0x0200">
1229 Thread is parked, for example: <code>LockSupport.park</code>,
1230 <code>LockSupport.parkUtil</code> and <code>LockSupport.parkNanos</code>.
1231 </constant>
1232 <constant id="JVMTI_THREAD_STATE_SUSPENDED" num="0x100000">
1233 Thread suspended.
1234 <code>java.lang.Thread.suspend()</code>
1235 or a <jvmti/> suspend function
1236 (such as <functionlink id="SuspendThread"></functionlink>)
1237 has been called on the thread. If this bit
1238 is set, the other bits refer to the thread state before suspension.
1239 </constant>
1240 <constant id="JVMTI_THREAD_STATE_INTERRUPTED" num="0x200000">
1241 Thread has been interrupted.
1242 </constant>
1243 <constant id="JVMTI_THREAD_STATE_IN_NATIVE" num="0x400000">
1244 Thread is in native code--that is, a native method is running
1245 which has not called back into the VM or Java programming
1246 language code.
1247 <p/>
1248 This flag is not set when running VM compiled Java programming
1249 language code nor is it set when running VM code or
1250 VM support code. Native VM interface functions, such as JNI and
1251 <jvmti/> functions, may be implemented as VM code.
1252 </constant>
1253 <constant id="JVMTI_THREAD_STATE_VENDOR_1" num="0x10000000">
1254 Defined by VM vendor.
1255 </constant>
1256 <constant id="JVMTI_THREAD_STATE_VENDOR_2" num="0x20000000">
1257 Defined by VM vendor.
1258 </constant>
1259 <constant id="JVMTI_THREAD_STATE_VENDOR_3" num="0x40000000">
1260 Defined by VM vendor.
1261 </constant>
1262 </constants>
1263 The following definitions are used to convert <jvmti/> thread state
1264 to <code>java.lang.Thread.State</code> style states.
1265 <constants id="jvmtiJavaLangThreadState" label="java.lang.Thread.State Conversion Masks" kind="bits">
1266 <constant id="JVMTI_JAVA_LANG_THREAD_STATE_MASK"
1267 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">
1268 Mask the state with this before comparison
1269 </constant>
1270 <constant id="JVMTI_JAVA_LANG_THREAD_STATE_NEW"
1271 num="0">
1272 <code>java.lang.Thread.State.NEW</code>
1273 </constant>
1274 <constant id="JVMTI_JAVA_LANG_THREAD_STATE_TERMINATED"
1275 num="JVMTI_THREAD_STATE_TERMINATED">
1276 <code>java.lang.Thread.State.TERMINATED</code>
1277 </constant>
1278 <constant id="JVMTI_JAVA_LANG_THREAD_STATE_RUNNABLE"
1279 num="JVMTI_THREAD_STATE_ALIVE | JVMTI_THREAD_STATE_RUNNABLE">
1280 <code>java.lang.Thread.State.RUNNABLE</code>
1281 </constant>
1282 <constant id="JVMTI_JAVA_LANG_THREAD_STATE_BLOCKED"
1283 num="JVMTI_THREAD_STATE_ALIVE | JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER">
1284 <code>java.lang.Thread.State.BLOCKED</code>
1285 </constant>
1286 <constant id="JVMTI_JAVA_LANG_THREAD_STATE_WAITING"
1287 num="JVMTI_THREAD_STATE_ALIVE | JVMTI_THREAD_STATE_WAITING | JVMTI_THREAD_STATE_WAITING_INDEFINITELY">
1288 <code>java.lang.Thread.State.WAITING</code>
1289 </constant>
1290 <constant id="JVMTI_JAVA_LANG_THREAD_STATE_TIMED_WAITING"
1291 num="JVMTI_THREAD_STATE_ALIVE | JVMTI_THREAD_STATE_WAITING | JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT">
1292 <code>java.lang.Thread.State.TIMED_WAITING</code>
1293 </constant>
1294 </constants>
1295 <b>Rules</b>
1296 <p/>
1297 There can be no more than one answer to a question, although there can be no
1298 answer (because the answer is unknown, does not apply, or none of the answers is
1299 correct). An answer is set only when the enclosing answers match.
1300 That is, no more than one of
1301 <ul type="circle">
1302 <li><code>JVMTI_THREAD_STATE_RUNNABLE</code></li>
1303 <li><code>JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER</code></li>
1304 <li><code>JVMTI_THREAD_STATE_WAITING</code></li>
1305 </ul>
1306 can be set (a <tm>J2SE</tm> compliant implementation will always set
1307 one of these if <code>JVMTI_THREAD_STATE_ALIVE</code> is set).
1308 And if any of these are set, the enclosing answer
1309 <code>JVMTI_THREAD_STATE_ALIVE</code> is set.
1310 No more than one of
1311 <ul type="circle">
1312 <li><code>JVMTI_THREAD_STATE_WAITING_INDEFINITELY</code></li>
1313 <li><code>JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT</code></li>
1314 </ul>
1315 can be set (a <tm>J2SE</tm> compliant implementation will always set
1316 one of these if <code>JVMTI_THREAD_STATE_WAITING</code> is set).
1317 And if either is set, the enclosing answers
1318 <code>JVMTI_THREAD_STATE_ALIVE</code> and
1319 <code>JVMTI_THREAD_STATE_WAITING</code> are set.
1320 No more than one of
1321 <ul type="circle">
1322 <li><code>JVMTI_THREAD_STATE_IN_OBJECT_WAIT</code></li>
1323 <li><code>JVMTI_THREAD_STATE_PARKED</code></li>
1324 <li><code>JVMTI_THREAD_STATE_SLEEPING</code></li>
1325 </ul>
1326 can be set. And if any of these is set, the enclosing answers
1327 <code>JVMTI_THREAD_STATE_ALIVE</code> and
1328 <code>JVMTI_THREAD_STATE_WAITING</code> are set.
1329 Also, if <code>JVMTI_THREAD_STATE_SLEEPING</code> is set,
1330 then <code>JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT</code> is set.
1331 If a state <i>A</i> is implemented using the mechanism of
1332 state <i>B</i> then it is state <i>A</i> which
1333 is returned by this function.
1334 For example, if <code>Thread.sleep(long)</code>
1335 is implemented using <code>Object.wait(long)</code>
1336 then it is still <code>JVMTI_THREAD_STATE_SLEEPING</code>
1337 which is returned.
1338 More than one of
1339 <ul type="circle">
1340 <li><code>JVMTI_THREAD_STATE_SUSPENDED</code></li>
1341 <li><code>JVMTI_THREAD_STATE_INTERRUPTED</code></li>
1342 <li><code>JVMTI_THREAD_STATE_IN_NATIVE</code></li>
1343 </ul>
1344 can be set, but if any is set,
1345 <code>JVMTI_THREAD_STATE_ALIVE</code> is set.
1346 <p/>
1347 And finally,
1348 <code>JVMTI_THREAD_STATE_TERMINATED</code> cannot be set unless
1349 <code>JVMTI_THREAD_STATE_ALIVE</code> is not set.
1350 <p/>
1351 The thread state representation is designed for extension in future versions
1352 of the specification; thread state values should be used accordingly, that is
1353 they should not be used as ordinals.
1354 Most queries can be made by testing a single bit, if use in a switch statement is desired,
1355 the state bits should be masked with the interesting bits.
1356 All bits not defined above are reserved for future use.
1357 A VM, compliant to the current specification, must set reserved bits to zero.
1358 An agent should ignore reserved bits --
1359 they should not be assumed to be zero and thus should not be included in comparisons.
1360 <p/>
1361 <b>Examples</b>
1362 <p/>
1363 Note that the values below exclude reserved and vendor bits.
1364 <p/>
1365 The state of a thread blocked at a <code>synchronized</code>-statement would be:
1366 <example>
1367 JVMTI_THREAD_STATE_ALIVE + JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER
1368 </example>
1369 The state of a thread which hasn't started yet would be:
1370 <example>
1371 0
1372 </example>
1373 The state of a thread at a <code>Object.wait(3000)</code> would be:
1374 <example>
1375 JVMTI_THREAD_STATE_ALIVE + JVMTI_THREAD_STATE_WAITING +
1376 JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT +
1377 JVMTI_THREAD_STATE_MONITOR_WAITING
1378 </example>
1379 The state of a thread suspended while runnable would be:
1380 <example>
1381 JVMTI_THREAD_STATE_ALIVE + JVMTI_THREAD_STATE_RUNNABLE + JVMTI_THREAD_STATE_SUSPENDED
1382 </example>
1383 <p/>
1384 <b>Testing the State</b>
1385 <p/>
1386 In most cases, the thread state can be determined by testing the one bit corresponding
1387 to that question. For example, the code to test if a thread is sleeping:
1388 <example>
1389 jint state;
1390 jvmtiError err;
1391
1392 err = (*jvmti)->GetThreadState(jvmti, thread, &state);
1393 if (err == JVMTI_ERROR_NONE) {
1394 if (state & JVMTI_THREAD_STATE_SLEEPING) { ...
1395 </example>
1396 <p/>
1397 For waiting (that is, in <code>Object.wait</code>, parked, or sleeping) it would be:
1398 <example>
1399 if (state & JVMTI_THREAD_STATE_WAITING) { ...
1400 </example>
1401 For some states, more than one bit will need to be tested as is the case
1402 when testing if a thread has not yet been started:
1403 <example>
1404 if ((state & (JVMTI_THREAD_STATE_ALIVE | JVMTI_THREAD_STATE_TERMINATED)) == 0) { ...
1405 </example>
1406 To distinguish timed from untimed <code>Object.wait</code>:
1407 <example>
1408 if (state & JVMTI_THREAD_STATE_IN_OBJECT_WAIT) {
1409 if (state & JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT) {
1410 printf("in Object.wait(long timeout)\n");
1411 } else {
1412 printf("in Object.wait()\n");
1413 }
1414 }
1415 </example>
1416 <p/>
1417 <b>Relationship to <code>java.lang.Thread.State</code></b>
1418 <p/>
1419 The thread state represented by <code>java.lang.Thread.State</code>
1420 returned from <code>java.lang.Thread.getState()</code> is a subset of the
1421 information returned from this function.
1422 The corresponding <code>java.lang.Thread.State</code> can be determined
1423 by using the provided conversion masks.
1424 For example, this returns the name of the <code>java.lang.Thread.State</code> thread state:
1425 <example>
1426 err = (*jvmti)->GetThreadState(jvmti, thread, &state);
1427 abortOnError(err);
1428 switch (state & JVMTI_JAVA_LANG_THREAD_STATE_MASK) {
1429 case JVMTI_JAVA_LANG_THREAD_STATE_NEW:
1430 return "NEW";
1431 case JVMTI_JAVA_LANG_THREAD_STATE_TERMINATED:
1432 return "TERMINATED";
1433 case JVMTI_JAVA_LANG_THREAD_STATE_RUNNABLE:
1434 return "RUNNABLE";
1435 case JVMTI_JAVA_LANG_THREAD_STATE_BLOCKED:
1436 return "BLOCKED";
1437 case JVMTI_JAVA_LANG_THREAD_STATE_WAITING:
1438 return "WAITING";
1439 case JVMTI_JAVA_LANG_THREAD_STATE_TIMED_WAITING:
1440 return "TIMED_WAITING";
1441 }
1442 </example>
1443 </description>
1444 <origin>new</origin>
1445 <capabilities>
1446 </capabilities>
1447 <parameters>
1448 <param id="thread">
1449 <jthread null="current" started="maybe" impl="noconvert"/>
1450 <description>
1451 The thread to query.
1452 </description>
1453 </param>
1454 <param id="thread_state_ptr">
1455 <outptr><jint/></outptr>
1456 <description>
1457 On return, points to state flags,
1458 as defined by the <internallink id="jvmtiThreadState">Thread State Flags</internallink>.
1459 </description>
1460 </param>
1461 </parameters>
1462 <errors>
1463 </errors>
1464 </function>
1465
1466 <function id="GetCurrentThread" phase="start" num="18" since="1.1">
1467 <synopsis>Get Current Thread</synopsis>
1468 <description>
1469 Get the current thread.
1470 The current thread is the Java programming language thread which has called the function.
1471 <p/>
1472 Note that most <jvmti/> functions that take a thread
1473 as an argument will accept <code>NULL</code> to mean
1474 the current thread.
1475 </description>
1476 <origin>new</origin>
1477 <capabilities>
1478 </capabilities>
1479 <parameters>
1480 <param id="thread_ptr">
1481 <outptr><jthread/></outptr>
1482 <description>
1483 On return, points to the current thread.
1484 </description>
1485 </param>
1486 </parameters>
1487 <errors>
1488 </errors>
1489 </function>
1490
1491 <function id="GetAllThreads" num="4">
1492 <synopsis>Get All Threads</synopsis>
1493 <description>
1494 Get all live threads.
1495 The threads are Java programming language threads;
1496 that is, threads that are attached to the VM.
1497 A thread is live if <code>java.lang.Thread.isAlive()</code>
1498 would return <code>true</code>, that is, the thread has
1499 been started and has not yet died.
1500 The universe of threads is determined by the context of the <jvmti/>
1501 environment, which typically is all threads attached to the VM.
1502 Note that this includes <jvmti/> agent threads
1503 (see <functionlink id="RunAgentThread"/>).
1504 </description>
1505 <origin>jvmdi</origin>
1506 <capabilities>
1507 </capabilities>
1508 <parameters>
1509 <param id="threads_count_ptr">
1510 <outptr><jint/></outptr>
1511 <description>
1512 On return, points to the number of running threads.
1513 </description>
1514 </param>
1515 <param id="threads_ptr">
1516 <allocbuf outcount="threads_count_ptr"><jthread/></allocbuf>
1517 <description>
1518 On return, points to an array of references, one
1519 for each running thread.
1520 </description>
1521 </param>
1522 </parameters>
1523 <errors>
1524 </errors>
1525 </function>
1526
1527 <function id="SuspendThread" num="5">
1528 <synopsis>Suspend Thread</synopsis>
1529 <description>
1530 Suspend the specified thread. If the calling thread is specified,
1531 this function will not return until some other thread calls
1532 <functionlink id="ResumeThread"></functionlink>.
1533 If the thread is currently suspended, this function
1534 does nothing and returns an error.
1535 </description>
1536 <origin>jvmdi</origin>
1537 <capabilities>
1538 <required id="can_suspend"></required>
1539 </capabilities>
1540 <parameters>
1541 <param id="thread">
1542 <jthread null="current"/>
1543 <description>
1544 The thread to suspend.
1545 </description>
1546 </param>
1547 </parameters>
1548 <errors>
1549 <error id="JVMTI_ERROR_THREAD_SUSPENDED">
1550 Thread already suspended.
1551 </error>
1552 </errors>
1553 </function>
1554
1555 <elide>
1556 <function id="SuspendAllThreads" num="101">
1557 <synopsis>Suspend All Threads</synopsis>
1558 <description>
1559 <issue>
1560 There has been no explicit call for this function, and it will
1561 thus be removed if there is no interest.
1562 </issue>
1563 Suspend all live threads except:
1564 <ul>
1565 <li>already suspended threads</li>
1566 <li>those listed in <paramlink id="except_list"></paramlink></li>
1567 <li>certain system (non application) threads, as determined
1568 by the VM implementation</li>
1569 </ul>
1570 The threads are Java programming language threads;
1571 native threads which are not attached to the VM are not
1572 Java programming language threads.
1573 A thread is live if <code>java.lang.Thread.isAlive()</code>
1574 would return <code>true</code>, that is, the thread has
1575 been started and has not yet died.
1576 The universe of threads is determined
1577 by the context of the <jvmti/>
1578 environment, which, typically, is all threads attached to the VM,
1579 except critical VM internal threads and <jvmti/> agent threads
1580 (see <functionlink id="RunAgentThread"/>).
1581 <p/>
1582 If the calling thread is specified,
1583 all other threads are suspended first then the caller thread is suspended -
1584 this function will not return until some other thread calls
1585 <functionlink id="ResumeThread"></functionlink>.
1586 <p/>
1587 The list of actually
1588 suspended threads is returned in
1589 <paramlink id="suspended_list_ptr"></paramlink>.
1590 Suspension is as defined in <functionlink id="SuspendThread"></functionlink>.
1591 <functionlink id="ResumeThreadList"></functionlink>
1592 can be used to resume the suspended threads.
1593 </description>
1594 <origin>new</origin>
1595 <capabilities>
1596 <required id="can_suspend"></required>
1597 </capabilities>
1598 <parameters>
1599 <param id="except_count">
1600 <jint min="0"/>
1601 <description>
1602 The number of threads in the list of threads not to be suspended.
1603 </description>
1604 </param>
1605 <param id="except_list">
1606 <inbuf incount="except_count">
1607 <jthread/>
1608 <nullok>not an error if <code>except_count == 0</code></nullok>
1609 </inbuf>
1610 <description>
1611 The list of threads not to be suspended.
1612 </description>
1613 </param>
1614 <param id="suspended_count_ptr">
1615 <outptr><jint/></outptr>
1616 <description>
1617 On return, points to the number of threads suspended by this call.
1618 </description>
1619 </param>
1620 <param id="suspended_list_ptr">
1621 <allocbuf outcount="suspended_count_ptr"><jthread/></allocbuf>
1622 <description>
1623 On return, points to an array of references, one
1624 for each thread suspended.
1625 </description>
1626 </param>
1627 </parameters>
1628 <errors>
1629 <error id="JVMTI_ERROR_INVALID_THREAD">
1630 A thread in <paramlink id="except_list"></paramlink> was invalid.
1631 </error>
1632 <error id="JVMTI_ERROR_NULL_POINTER">
1633 Both <paramlink id="except_list"></paramlink> was <code>NULL</code>
1634 and <paramlink id="except_count"></paramlink> was non-zero.
1635 </error>
1636 </errors>
1637 </function>
1638 </elide>
1639
1640 <function id="SuspendThreadList" num="92">
1641 <synopsis>Suspend Thread List</synopsis>
1642 <description>
1643 Suspend the <paramlink id="request_count"></paramlink>
1644 threads specified in the
1645 <paramlink id="request_list"></paramlink> array.
1646 Threads may be resumed with
1647 <functionlink id="ResumeThreadList"></functionlink> or
1648 <functionlink id="ResumeThread"></functionlink>.
1649 If the calling thread is specified in the
1650 <paramlink id="request_list"></paramlink> array, this function will
1651 not return until some other thread resumes it.
1652 Errors encountered in the suspension of a thread
1653 are returned in the <paramlink id="results"></paramlink>
1654 array, <b>not</b> in the return value of this function.
1655 Threads that are currently suspended do not change state.
1656 </description>
1657 <origin>jvmdi</origin>
1658 <capabilities>
1659 <required id="can_suspend"></required>
1660 </capabilities>
1661 <parameters>
1662 <param id="request_count">
1663 <jint min="0"/>
1664 <description>
1665 The number of threads to suspend.
1666 </description>
1667 </param>
1668 <param id="request_list">
1669 <inbuf incount="request_count"><jthread/></inbuf>
1670 <description>
1671 The list of threads to suspend.
1672 </description>
1673 </param>
1674 <param id="results">
1675 <outbuf incount="request_count"><enum>jvmtiError</enum></outbuf>
1676 <description>
1677 An agent supplied array of
1678 <paramlink id="request_count"></paramlink> elements.
1679 On return, filled with the error code for
1680 the suspend of the corresponding thread.
1681 The error code will be
1682 <errorlink id="JVMTI_ERROR_NONE"></errorlink>
1683 if the thread was suspended by this call.
1684 Possible error codes are those specified
1685 for <functionlink id="SuspendThread"></functionlink>.
1686 </description>
1687 </param>
1688 </parameters>
1689 <errors>
1690 </errors>
1691 </function>
1692
1693 <function id="ResumeThread" num="6">
1694 <synopsis>Resume Thread</synopsis>
1695 <description>
1696 Resume a suspended thread.
1697 Any threads currently suspended through
1698 a <jvmti/> suspend function (eg.
1699 <functionlink id="SuspendThread"></functionlink>)
1700 or <code>java.lang.Thread.suspend()</code>
1701 will resume execution;
1702 all other threads are unaffected.
1703 </description>
1704 <origin>jvmdi</origin>
1705 <capabilities>
1706 <required id="can_suspend"></required>
1707 </capabilities>
1708 <parameters>
1709 <param id="thread">
1710 <jthread/>
1711 <description>
1712 The thread to resume.
1713 </description>
1714 </param>
1715 </parameters>
1716 <errors>
1717 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
1718 Thread was not suspended.
1719 </error>
1720 <error id="JVMTI_ERROR_INVALID_TYPESTATE">
1721 The state of the thread has been modified, and is now inconsistent.
1722 </error>
1723 </errors>
1724 </function>
1725
1726 <function id="ResumeThreadList" num="93">
1727 <synopsis>Resume Thread List</synopsis>
1728 <description>
1729 Resume the <paramlink id="request_count"></paramlink>
1730 threads specified in the
1731 <paramlink id="request_list"></paramlink> array.
1732 Any thread suspended through
1733 a <jvmti/> suspend function (eg.
1734 <functionlink id="SuspendThreadList"></functionlink>)
1735 or <code>java.lang.Thread.suspend()</code>
1736 will resume execution.
1737 </description>
1738 <origin>jvmdi</origin>
1739 <capabilities>
1740 <required id="can_suspend"></required>
1741 </capabilities>
1742 <parameters>
1743 <param id="request_count">
1744 <jint min="0"/>
1745 <description>
1746 The number of threads to resume.
1747 </description>
1748 </param>
1749 <param id="request_list">
1750 <inbuf incount="request_count"><jthread/></inbuf>
1751 <description>
1752 The threads to resume.
1753 </description>
1754 </param>
1755 <param id="results">
1756 <outbuf incount="request_count"><enum>jvmtiError</enum></outbuf>
1757 <description>
1758 An agent supplied array of
1759 <paramlink id="request_count"></paramlink> elements.
1760 On return, filled with the error code for
1761 the resume of the corresponding thread.
1762 The error code will be
1763 <errorlink id="JVMTI_ERROR_NONE"></errorlink>
1764 if the thread was suspended by this call.
1765 Possible error codes are those specified
1766 for <functionlink id="ResumeThread"></functionlink>.
1767 </description>
1768 </param>
1769 </parameters>
1770 <errors>
1771 </errors>
1772 </function>
1773
1774 <function id="StopThread" num="7">
1775 <synopsis>Stop Thread</synopsis>
1776 <description>
1777 Send the specified asynchronous exception to the specified thread
1778 (similar to <code>java.lang.Thread.stop</code>).
1779 Normally, this function is used to kill the specified thread with an
1780 instance of the exception <code>ThreadDeath</code>.
1781 </description>
1782 <origin>jvmdi</origin>
1783 <capabilities>
1784 <required id="can_signal_thread"></required>
1785 </capabilities>
1786 <parameters>
1787 <param id="thread">
1788 <jthread/>
1789 <description>
1790 The thread to stop.
1791 </description>
1792 </param>
1793 <param id="exception">
1794 <jobject/>
1795 <description>
1796 The asynchronous exception object.
1797 </description>
1798 </param>
1799 </parameters>
1800 <errors>
1801 </errors>
1802 </function>
1803
1804 <function id="InterruptThread" num="8">
1805 <synopsis>Interrupt Thread</synopsis>
1806 <description>
1807 Interrupt the specified thread
1808 (similar to <code>java.lang.Thread.interrupt</code>).
1809 </description>
1810 <origin>jvmdi</origin>
1811 <capabilities>
1812 <required id="can_signal_thread"></required>
1813 </capabilities>
1814 <parameters>
1815 <param id="thread">
1816 <jthread impl="noconvert"/>
1817 <description>
1818 The thread to interrupt.
1819 </description>
1820 </param>
1821 </parameters>
1822 <errors>
1823 </errors>
1824 </function>
1825
1826 <function id="GetThreadInfo" num="9">
1827 <synopsis>Get Thread Info</synopsis>
1828 <typedef id="jvmtiThreadInfo" label="Thread information structure">
1829 <field id="name">
1830 <allocfieldbuf><char/></allocfieldbuf>
1831 <description>
1832 The thread name, encoded as a
1833 <internallink id="mUTF">modified UTF-8</internallink> string.
1834 </description>
1835 </field>
1836 <field id="priority">
1837 <jint/>
1838 <description>
1839 The thread priority. See the thread priority constants:
1840 <datalink id="jvmtiThreadPriority"></datalink>.
1841 </description>
1842 </field>
1843 <field id="is_daemon">
1844 <jboolean/>
1845 <description>
1846 Is this a daemon thread?
1847 </description>
1848 </field>
1849 <field id="thread_group">
1850 <jthreadGroup/>
1851 <description>
1852 The thread group to which this thread belongs.
1853 <code>NULL</code> if the thread has died.
1854 </description>
1855 </field>
1856 <field id="context_class_loader">
1857 <jobject/>
1858 <description>
1859 The context class loader associated with this thread.
1860 </description>
1861 </field>
1862 </typedef>
1863 <description>
1864 Get thread information. The fields of the <datalink id="jvmtiThreadInfo"/> structure
1865 are filled in with details of the specified thread.
1866 </description>
1867 <origin>jvmdi</origin>
1868 <capabilities>
1869 </capabilities>
1870 <parameters>
1871 <param id="thread">
1872 <jthread null="current" impl="noconvert" started="maybe"/>
1873 <description>
1874 The thread to query.
1875 </description>
1876 </param>
1877 <param id="info_ptr">
1878 <outptr><struct>jvmtiThreadInfo</struct></outptr>
1879 <description>
1880 On return, filled with information describing the specified thread.
1881 <p/>
1882 For JDK 1.1 implementations that don't
1883 recognize context class loaders,
1884 the <code>context_class_loader</code> field will be NULL.
1885 </description>
1886 </param>
1887 </parameters>
1888 <errors>
1889 </errors>
1890 </function>
1891
1892 <function id="GetOwnedMonitorInfo" num="10">
1893 <synopsis>Get Owned Monitor Info</synopsis>
1894 <description>
1895 Get information about the monitors owned by the
1896 specified thread.
1897 </description>
1898 <origin>jvmdiClone</origin>
1899 <capabilities>
1900 <required id="can_get_owned_monitor_info"></required>
1901 </capabilities>
1902 <parameters>
1903 <param id="thread">
1904 <jthread null="current"/>
1905 <description>
1906 The thread to query.
1907 </description>
1908 </param>
1909 <param id="owned_monitor_count_ptr">
1910 <outptr><jint/></outptr>
1911 <description>
1912 The number of monitors returned.
1913 </description>
1914 </param>
1915 <param id="owned_monitors_ptr">
1916 <allocbuf outcount="owned_monitor_count_ptr"><jobject/></allocbuf>
1917 <description>
1918 The array of owned monitors.
1919 </description>
1920 </param>
1921 </parameters>
1922 <errors>
1923 </errors>
1924 </function>
1925
1926 <function id="GetOwnedMonitorStackDepthInfo" num="153" since="1.1">
1927 <synopsis>Get Owned Monitor Stack Depth Info</synopsis>
1928 <typedef id="jvmtiMonitorStackDepthInfo"
1929 label="Monitor stack depth information structure">
1930 <field id="monitor">
1931 <jobject/>
1932 <description>
1933 The owned monitor.
1934 </description>
1935 </field>
1936 <field id="stack_depth">
1937 <jint/>
1938 <description>
1939 The stack depth. Corresponds to the stack depth used in the
1940 <internallink id="stack">Stack Frame functions</internallink>.
1941 That is, zero is the current frame, one is the frame which
1942 called the current frame. And it is negative one if the
1943 implementation cannot determine the stack depth (e.g., for
1944 monitors acquired by JNI <code>MonitorEnter</code>).
1945 </description>
1946 </field>
1947 </typedef>
1948 <description>
1949 Get information about the monitors owned by the
1950 specified thread and the depth of the stack frame which locked them.
1951 </description>
1952 <origin>new</origin>
1953 <capabilities>
1954 <required id="can_get_owned_monitor_stack_depth_info"></required>
1955 </capabilities>
1956 <parameters>
1957 <param id="thread">
1958 <jthread null="current"/>
1959 <description>
1960 The thread to query.
1961 </description>
1962 </param>
1963 <param id="monitor_info_count_ptr">
1964 <outptr><jint/></outptr>
1965 <description>
1966 The number of monitors returned.
1967 </description>
1968 </param>
1969 <param id="monitor_info_ptr">
1970 <allocbuf outcount="monitor_info_count_ptr">
1971 <struct>jvmtiMonitorStackDepthInfo</struct>
1972 </allocbuf>
1973 <description>
1974 The array of owned monitor depth information.
1975 </description>
1976 </param>
1977 </parameters>
1978 <errors>
1979 </errors>
1980 </function>
1981
1982 <function id="GetCurrentContendedMonitor" num="11">
1983 <synopsis>Get Current Contended Monitor</synopsis>
1984 <description>
1985 Get the object, if any, whose monitor the specified thread is waiting to
1986 enter or waiting to regain through <code>java.lang.Object.wait</code>.
1987 </description>
1988 <origin>jvmdi</origin>
1989 <capabilities>
1990 <required id="can_get_current_contended_monitor"></required>
1991 </capabilities>
1992 <parameters>
1993 <param id="thread">
1994 <jthread null="current"/>
1995 <description>
1996 The thread to query.
1997 </description>
1998 </param>
1999 <param id="monitor_ptr">
2000 <outptr><jobject/></outptr>
2001 <description>
2002 On return, filled with the current contended monitor, or
2003 NULL if there is none.
2004 </description>
2005 </param>
2006 </parameters>
2007 <errors>
2008 </errors>
2009 </function>
2010
2011 <callback id="jvmtiStartFunction">
2012 <void/>
2013 <synopsis>Agent Start Function</synopsis>
2014 <description>
2015 Agent supplied callback function.
2016 This function is the entry point for an agent thread
2017 started with
2018 <functionlink id="RunAgentThread"></functionlink>.
2019 </description>
2020 <parameters>
2021 <param id="jvmti_env">
2022 <outptr>
2023 <struct>jvmtiEnv</struct>
2024 </outptr>
2025 <description>
2026 The <jvmti/> environment.
2027 </description>
2028 </param>
2029 <param id="jni_env">
2030 <outptr>
2031 <struct>JNIEnv</struct>
2032 </outptr>
2033 <description>
2034 The JNI environment.
2035 </description>
2036 </param>
2037 <param id="arg">
2038 <outptr>
2039 <void/>
2040 </outptr>
2041 <description>
2042 The <code>arg</code> parameter passed to
2043 <functionlink id="RunAgentThread"></functionlink>.
2044 </description>
2045 </param>
2046 </parameters>
2047 </callback>
2048
2049 <function id="RunAgentThread" num="12">
2050 <synopsis>Run Agent Thread</synopsis>
2051 <description>
2052 Starts the execution of an agent thread. with the specified native function.
2053 The parameter <paramlink id="arg"></paramlink> is forwarded on to the
2054 <functionlink id="jvmtiStartFunction">start function</functionlink>
2055 (specified with <paramlink id="proc"></paramlink>) as its single argument.
2056 This function allows the creation of agent threads
2057 for handling communication with another process or for handling events
2058 without the need to load a special subclass of <code>java.lang.Thread</code> or
2059 implementer of <code>java.lang.Runnable</code>.
2060 Instead, the created thread can run entirely in native code.
2061 However, the created thread does require a newly created instance
2062 of <code>java.lang.Thread</code> (referenced by the argument <code>thread</code>) to
2063 which it will be associated.
2064 The thread object can be created with JNI calls.
2065 <p/>
2066 The following common thread priorities are provided for your convenience:
2067 <constants id="jvmtiThreadPriority" label="Thread Priority Constants" kind="const">
2068 <constant id="JVMTI_THREAD_MIN_PRIORITY" num="1">
2069 Minimum possible thread priority
2070 </constant>
2071 <constant id="JVMTI_THREAD_NORM_PRIORITY" num="5">
2072 Normal thread priority
2073 </constant>
2074 <constant id="JVMTI_THREAD_MAX_PRIORITY" num="10">
2075 Maximum possible thread priority
2076 </constant>
2077 </constants>
2078 <p/>
2079 The new thread is started as a daemon thread with the specified
2080 <paramlink id="priority"></paramlink>.
2081 If enabled, a <eventlink id="ThreadStart"/> event will be sent.
2082 <p/>
2083 Since the thread has been started, the thread will be live when this function
2084 returns, unless the thread has died immediately.
2085 <p/>
2086 The thread group of the thread is ignored -- specifically, the thread is not
2087 added to the thread group and the thread is not seen on queries of the thread
2088 group at either the Java programming language or <jvmti/> levels.
2089 <p/>
2090 The thread is not visible to Java programming language queries but is
2091 included in <jvmti/> queries (for example,
2092 <functionlink id="GetAllThreads"/> and
2093 <functionlink id="GetAllStackTraces"/>).
2094 <p/>
2095 Upon execution of <code>proc</code>, the new thread will be attached to the
2096 VM--see the JNI documentation on
2097 <externallink id="http://docs.oracle.com/javase/7/docs/technotes/guides/jni/spec/invocation.html#wp1060"
2098 >Attaching to the VM</externallink>.
2099 </description>
2100 <origin>jvmdiClone</origin>
2101 <capabilities>
2102 </capabilities>
2103 <parameters>
2104 <param id="thread">
2105 <jthread impl="noconvert" started="no"/>
2106 <description>
2107 The thread to run.
2108 </description>
2109 </param>
2110 <param id="proc">
2111 <ptrtype>
2112 <struct>jvmtiStartFunction</struct>
2113 </ptrtype>
2114 <description>
2115 The start function.
2116 </description>
2117 </param>
2118 <param id="arg">
2119 <inbuf>
2120 <void/>
2121 <nullok><code>NULL</code> is passed to the start function</nullok>
2122 </inbuf>
2123 <description>
2124 The argument to the start function.
2125 </description>
2126 </param>
2127 <param id="priority">
2128 <jint/>
2129 <description>
2130 The priority of the started thread. Any thread
2131 priority allowed by <code>java.lang.Thread.setPriority</code> can be used including
2132 those in <datalink id="jvmtiThreadPriority"></datalink>.
2133 </description>
2134 </param>
2135 </parameters>
2136 <errors>
2137 <error id="JVMTI_ERROR_INVALID_PRIORITY">
2138 <paramlink id="priority"/> is less than
2139 <datalink id="JVMTI_THREAD_MIN_PRIORITY"/>
2140 or greater than
2141 <datalink id="JVMTI_THREAD_MAX_PRIORITY"/>
2142 </error>
2143 </errors>
2144 </function>
2145
2146 <function id="SetThreadLocalStorage" jkernel="yes" impl="notrace" phase="start" num="103">
2147 <synopsis>Set Thread Local Storage</synopsis>
2148 <description>
2149 The VM stores a pointer value associated with each environment-thread
2150 pair. This pointer value is called <i>thread-local storage</i>.
2151 This value is <code>NULL</code> unless set with this function.
2152 Agents can allocate memory in which they store thread specific
2153 information. By setting thread-local storage it can then be
2154 accessed with
2155 <functionlink id="GetThreadLocalStorage"></functionlink>.
2156 <p/>
2157 This function is called by the agent to set the value of the <jvmti/>
2158 thread-local storage. <jvmti/> supplies to the agent a pointer-size
2159 thread-local storage that can be used to record per-thread
2160 information.
2161 </description>
2162 <origin>jvmpi</origin>
2163 <capabilities>
2164 </capabilities>
2165 <parameters>
2166 <param id="thread">
2167 <jthread null="current"/>
2168 <description>
2169 Store to this thread.
2170 </description>
2171 </param>
2172 <param id="data">
2173 <inbuf>
2174 <void/>
2175 <nullok>value is set to <code>NULL</code></nullok>
2176 </inbuf>
2177 <description>
2178 The value to be entered into the thread-local storage.
2179 </description>
2180 </param>
2181 </parameters>
2182 <errors>
2183 </errors>
2184 </function>
2185
2186 <function id="GetThreadLocalStorage" jkernel="yes" impl="innative notrace" phase="start" num="102">
2187 <synopsis>Get Thread Local Storage</synopsis>
2188 <description>
2189 Called by the agent to get the value of the <jvmti/> thread-local
2190 storage.
2191 </description>
2192 <origin>jvmpi</origin>
2193 <capabilities>
2194 </capabilities>
2195 <parameters>
2196 <param id="thread">
2197 <jthread null="current" impl="noconvert"/>
2198 <description>
2199 Retrieve from this thread.
2200 </description>
2201 </param>
2202 <param id="data_ptr">
2203 <agentbuf><void/></agentbuf>
2204 <description>
2205 Pointer through which the value of the thread local
2206 storage is returned.
2207 If thread-local storage has not been set with
2208 <functionlink id="SetThreadLocalStorage"></functionlink> the returned
2209 pointer is <code>NULL</code>.
2210 </description>
2211 </param>
2212 </parameters>
2213 <errors>
2214 </errors>
2215 </function>
2216
2217 </category>
2218
2219 <category id="thread_groups" label="Thread Group">
2220 <intro>
2221 </intro>
2222
2223 <function id="GetTopThreadGroups" num="13">
2224 <synopsis>Get Top Thread Groups</synopsis>
2225 <description>
2226 Return all top-level (parentless) thread groups in the VM.
2227 </description>
2228 <origin>jvmdi</origin>
2229 <capabilities>
2230 </capabilities>
2231 <parameters>
2232 <param id="group_count_ptr">
2233 <outptr><jint/></outptr>
2234 <description>
2235 On return, points to the number of top-level thread groups.
2236 </description>
2237 </param>
2238 <param id="groups_ptr">
2239 <allocbuf outcount="group_count_ptr"><jthreadGroup/></allocbuf>
2240 <description>
2241 On return, refers to a pointer to the top-level thread group array.
2242 </description>
2243 </param>
2244 </parameters>
2245 <errors>
2246 </errors>
2247 </function>
2248
2249 <function id="GetThreadGroupInfo" num="14">
2250 <synopsis>Get Thread Group Info</synopsis>
2251 <typedef id="jvmtiThreadGroupInfo" label="Thread group information structure">
2252 <field id="parent">
2253 <jthreadGroup/>
2254 <description>
2255 The parent thread group.
2256 </description>
2257 </field>
2258 <field id="name">
2259 <allocfieldbuf><char/></allocfieldbuf>
2260 <description>
2261 The thread group's name, encoded as a
2262 <internallink id="mUTF">modified UTF-8</internallink> string.
2263 </description>
2264 </field>
2265 <field id="max_priority">
2266 <jint/>
2267 <description>
2268 The maximum priority for this thread group.
2269 </description>
2270 </field>
2271 <field id="is_daemon">
2272 <jboolean/>
2273 <description>
2274 Is this a daemon thread group?
2275 </description>
2276 </field>
2277 </typedef>
2278 <description>
2279 Get information about the thread group. The fields of the
2280 <functionlink id="jvmtiThreadGroupInfo"></functionlink> structure
2281 are filled in with details of the specified thread group.
2282 </description>
2283 <origin>jvmdi</origin>
2284 <capabilities>
2285 </capabilities>
2286 <parameters>
2287 <param id="group">
2288 <jthreadGroup/>
2289 <description>
2290 The thread group to query.
2291 </description>
2292 </param>
2293 <param id="info_ptr">
2294 <outptr><struct>jvmtiThreadGroupInfo</struct></outptr>
2295 <description>
2296 On return, filled with information describing the specified
2297 thread group.
2298 </description>
2299 </param>
2300 </parameters>
2301 <errors>
2302 </errors>
2303 </function>
2304
2305 <function id="GetThreadGroupChildren" num="15">
2306 <synopsis>Get Thread Group Children</synopsis>
2307 <description>
2308 Get the live threads and active subgroups in this thread group.
2309 </description>
2310 <origin>jvmdi</origin>
2311 <capabilities>
2312 </capabilities>
2313 <parameters>
2314 <param id="group">
2315 <jthreadGroup/>
2316 <description>
2317 The group to query.
2318 </description>
2319 </param>
2320 <param id="thread_count_ptr">
2321 <outptr><jint/></outptr>
2322 <description>
2323 On return, points to the number of live threads in this thread group.
2324 </description>
2325 </param>
2326 <param id="threads_ptr">
2327 <allocbuf outcount="thread_count_ptr"><jthread/></allocbuf>
2328 <description>
2329 On return, points to an array of the live threads in this thread group.
2330 </description>
2331 </param>
2332 <param id="group_count_ptr">
2333 <outptr><jint/></outptr>
2334 <description>
2335 On return, points to the number of active child thread groups
2336 </description>
2337 </param>
2338 <param id="groups_ptr">
2339 <allocbuf outcount="group_count_ptr"><jthreadGroup/></allocbuf>
2340 <description>
2341 On return, points to an array of the active child thread groups.
2342 </description>
2343 </param>
2344 </parameters>
2345 <errors>
2346 </errors>
2347 </function>
2348 </category>
2349
2350 <category id="stack" label="Stack Frame">
2351 <intro>
2352 These functions provide information about the stack of a thread.
2353 Stack frames are referenced by depth.
2354 The frame at depth zero is the current frame.
2355 <p/>
2356 Stack frames are as described in
2357 <vmspec chapter="3.6"/>,
2358 That is, they correspond to method
2359 invocations (including native methods) but do not correspond to platform native or
2360 VM internal frames.
2361 <p/>
2362 A <jvmti/> implementation may use method invocations to launch a thread and
2363 the corresponding frames may be included in the stack as presented by these functions --
2364 that is, there may be frames shown
2365 deeper than <code>main()</code> and <code>run()</code>.
2366 However this presentation must be consistent across all <jvmti/> functionality which
2367 uses stack frames or stack depth.
2368 </intro>
2369
2370 <typedef id="jvmtiFrameInfo" label="Stack frame information structure">
2371 <description>
2372 Information about a stack frame is returned in this structure.
2373 </description>
2374 <field id="method">
2375 <jmethodID/>
2376 <description>
2377 The method executing in this frame.
2378 </description>
2379 </field>
2380 <field id="location">
2381 <jlocation/>
2382 <description>
2383 The index of the instruction executing in this frame.
2384 <code>-1</code> if the frame is executing a native method.
2385 </description>
2386 </field>
2387 </typedef>
2388
2389 <typedef id="jvmtiStackInfo" label="Stack information structure">
2390 <description>
2391 Information about a set of stack frames is returned in this structure.
2392 </description>
2393 <field id="thread">
2394 <jthread/>
2395 <description>
2396 On return, the thread traced.
2397 </description>
2398 </field>
2399 <field id="state">
2400 <jint/>
2401 <description>
2402 On return, the thread state. See <functionlink id="GetThreadState"></functionlink>.
2403 </description>
2404 </field>
2405 <field id="frame_buffer">
2406 <outbuf incount="max_frame_count">
2407 <struct>jvmtiFrameInfo</struct>
2408 </outbuf>
2409 <description>
2410 On return, this agent allocated buffer is filled
2411 with stack frame information.
2412 </description>
2413 </field>
2414 <field id="frame_count">
2415 <jint/>
2416 <description>
2417 On return, the number of records filled into
2418 <code>frame_buffer</code>.
2419 This will be
2420 min(<code>max_frame_count</code>, <i>stackDepth</i>).
2421 </description>
2422 </field>
2423 </typedef>
2424
2425 <function id="GetStackTrace" num="104">
2426 <synopsis>Get Stack Trace</synopsis>
2427 <description>
2428 Get information about the stack of a thread.
2429 If <paramlink id="max_frame_count"></paramlink> is less than the depth of the stack,
2430 the <paramlink id="max_frame_count"></paramlink> topmost frames are returned,
2431 otherwise the entire stack is returned.
2432 The topmost frames, those most recently invoked, are at the beginning of the returned buffer.
2433 <p/>
2434 The following example causes up to five of the topmost frames
2435 to be returned and (if there are any frames) the currently
2436 executing method name to be printed.
2437 <example>
2438 jvmtiFrameInfo frames[5];
2439 jint count;
2440 jvmtiError err;
2441
2442 err = (*jvmti)->GetStackTrace(jvmti, aThread, 0, 5,
2443 frames, &count);
2444 if (err == JVMTI_ERROR_NONE && count >= 1) {
2445 char *methodName;
2446 err = (*jvmti)->GetMethodName(jvmti, frames[0].method,
2447 &methodName, NULL, NULL);
2448 if (err == JVMTI_ERROR_NONE) {
2449 printf("Executing method: %s", methodName);
2450 }
2451 }
2452 </example>
2453 <todo>
2454 check example code.
2455 </todo>
2456 <p/>
2457 The <paramlink id="thread"></paramlink> need not be suspended
2458 to call this function.
2459 <p/>
2460 The <functionlink id="GetLineNumberTable"></functionlink>
2461 function can be used to map locations to line numbers. Note that
2462 this mapping can be done lazily.
2463 </description>
2464 <origin>jvmpi</origin>
2465 <capabilities>
2466 </capabilities>
2467 <parameters>
2468 <param id="thread">
2469 <jthread null="current"/>
2470 <description>
2471 Fetch the stack trace of this thread.
2472 </description>
2473 </param>
2474 <param id="start_depth">
2475 <jint/>
2476 <description>
2477 Begin retrieving frames at this depth.
2478 If non-negative, count from the current frame,
2479 the first frame retrieved is at depth <code>start_depth</code>.
2480 For example, if zero, start from the current frame; if one, start from the
2481 caller of the current frame; if two, start from the caller of the
2482 caller of the current frame; and so on.
2483 If negative, count from below the oldest frame,
2484 the first frame retrieved is at depth <i>stackDepth</i><code> + start_depth</code>,
2485 where <i>stackDepth</i> is the count of frames on the stack.
2486 For example, if negative one, only the oldest frame is retrieved;
2487 if negative two, start from the frame called by the oldest frame.
2488 </description>
2489 </param>
2490 <param id="max_frame_count">
2491 <jint min="0"/>
2492 <description>
2493 The maximum number of <datalink id="jvmtiFrameInfo"/> records to retrieve.
2494 </description>
2495 </param>
2496 <param id="frame_buffer">
2497 <outbuf incount="max_frame_count" outcount="count_ptr">
2498 <struct>jvmtiFrameInfo</struct>
2499 </outbuf>
2500 <description>
2501 On return, this agent allocated buffer is filled
2502 with stack frame information.
2503 </description>
2504 </param>
2505 <param id="count_ptr">
2506 <outptr><jint/></outptr>
2507 <description>
2508 On return, points to the number of records filled in.
2509 For non-negative <code>start_depth</code>, this will be
2510 min(<code>max_frame_count</code>, <i>stackDepth</i><code> - start_depth</code>).
2511 For negative <code>start_depth</code>, this will be
2512 min(<code>max_frame_count</code>, <code>-start_depth</code>).
2513 </description>
2514 </param>
2515 </parameters>
2516 <errors>
2517 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
2518 <paramlink id="start_depth"/> is positive and greater than or equal to <i>stackDepth</i>.
2519 Or <paramlink id="start_depth"/> is negative and less than <i>-stackDepth</i>.
2520 </error>
2521 </errors>
2522 </function>
2523
2524
2525 <function id="GetAllStackTraces" num="100">
2526 <synopsis>Get All Stack Traces</synopsis>
2527 <description>
2528 Get information about the stacks of all live threads
2529 (including <internallink id="RunAgentThread">agent threads</internallink>).
2530 If <paramlink id="max_frame_count"/> is less than the depth of a stack,
2531 the <paramlink id="max_frame_count"/> topmost frames are returned for that thread,
2532 otherwise the entire stack is returned.
2533 The topmost frames, those most recently invoked, are at the beginning of the returned buffer.
2534 <p/>
2535 All stacks are collected simultaneously, that is, no changes will occur to the
2536 thread state or stacks between the sampling of one thread and the next.
2537 The threads need not be suspended.
2538
2539 <example>
2540 jvmtiStackInfo *stack_info;
2541 jint thread_count;
2542 int ti;
2543 jvmtiError err;
2544
2545 err = (*jvmti)->GetAllStackTraces(jvmti, MAX_FRAMES, &stack_info, &thread_count);
2546 if (err != JVMTI_ERROR_NONE) {
2547 ...
2548 }
2549 for (ti = 0; ti < thread_count; ++ti) {
2550 jvmtiStackInfo *infop = &stack_info[ti];
2551 jthread thread = infop->thread;
2552 jint state = infop->state;
2553 jvmtiFrameInfo *frames = infop->frame_buffer;
2554 int fi;
2555
2556 myThreadAndStatePrinter(thread, state);
2557 for (fi = 0; fi < infop->frame_count; fi++) {
2558 myFramePrinter(frames[fi].method, frames[fi].location);
2559 }
2560 }
2561 /* this one Deallocate call frees all data allocated by GetAllStackTraces */
2562 err = (*jvmti)->Deallocate(jvmti, stack_info);
2563 </example>
2564 <todo>
2565 check example code.
2566 </todo>
2567
2568 </description>
2569 <origin>new</origin>
2570 <capabilities>
2571 </capabilities>
2572 <parameters>
2573 <param id="max_frame_count">
2574 <jint min="0"/>
2575 <description>
2576 The maximum number of <datalink id="jvmtiFrameInfo"/> records to retrieve per thread.
2577 </description>
2578 </param>
2579 <param id="stack_info_ptr">
2580 <allocbuf>
2581 <struct>jvmtiStackInfo</struct>
2582 </allocbuf>
2583 <description>
2584 On return, this buffer is filled
2585 with stack information for each thread.
2586 The number of <datalink id="jvmtiStackInfo"/> records is determined
2587 by <paramlink id="thread_count_ptr"/>.
2588 <p/>
2589 Note that this buffer is allocated to include the <datalink id="jvmtiFrameInfo"/>
2590 buffers pointed to by <datalink id="jvmtiStackInfo.frame_buffer"/>.
2591 These buffers must not be separately deallocated.
2592 </description>
2593 </param>
2594 <param id="thread_count_ptr">
2595 <outptr><jint/></outptr>
2596 <description>
2597 The number of threads traced.
2598 </description>
2599 </param>
2600 </parameters>
2601 <errors>
2602 </errors>
2603 </function>
2604
2605 <function id="GetThreadListStackTraces" num="101">
2606 <synopsis>Get Thread List Stack Traces</synopsis>
2607 <description>
2608 Get information about the stacks of the supplied threads.
2609 If <paramlink id="max_frame_count"/> is less than the depth of a stack,
2610 the <paramlink id="max_frame_count"/> topmost frames are returned for that thread,
2611 otherwise the entire stack is returned.
2612 The topmost frames, those most recently invoked, are at the beginning of the returned buffer.
2613 <p/>
2614 All stacks are collected simultaneously, that is, no changes will occur to the
2615 thread state or stacks between the sampling one thread and the next.
2616 The threads need not be suspended.
2617 <p/>
2618 If a thread has not yet started or terminates before the stack information is collected,
2619 a zero length stack (<datalink id="jvmtiStackInfo.frame_count"/> will be zero)
2620 will be returned and the thread <datalink id="jvmtiStackInfo.state"/> can be checked.
2621 <p/>
2622 See the example for the similar function
2623 <functionlink id="GetAllStackTraces"/>.
2624 </description>
2625 <origin>new</origin>
2626 <capabilities>
2627 </capabilities>
2628 <parameters>
2629 <param id="thread_count">
2630 <jint min="0"/>
2631 <description>
2632 The number of threads to trace.
2633 </description>
2634 </param>
2635 <param id="thread_list">
2636 <inbuf incount="thread_count"><jthread/></inbuf>
2637 <description>
2638 The list of threads to trace.
2639 </description>
2640 </param>
2641 <param id="max_frame_count">
2642 <jint min="0"/>
2643 <description>
2644 The maximum number of <datalink id="jvmtiFrameInfo"/> records to retrieve per thread.
2645 </description>
2646 </param>
2647 <param id="stack_info_ptr">
2648 <allocbuf outcount="thread_count">
2649 <struct>jvmtiStackInfo</struct>
2650 </allocbuf>
2651 <description>
2652 On return, this buffer is filled
2653 with stack information for each thread.
2654 The number of <datalink id="jvmtiStackInfo"/> records is determined
2655 by <paramlink id="thread_count"/>.
2656 <p/>
2657 Note that this buffer is allocated to include the <datalink id="jvmtiFrameInfo"/>
2658 buffers pointed to by <datalink id="jvmtiStackInfo.frame_buffer"/>.
2659 These buffers must not be separately deallocated.
2660 </description>
2661 </param>
2662 </parameters>
2663 <errors>
2664 <error id="JVMTI_ERROR_INVALID_THREAD">
2665 An element in <paramlink id="thread_list"/> is not a thread object.
2666 </error>
2667 </errors>
2668 </function>
2669
2670 <elide>
2671 <function id="AsyncGetStackTrace" num="1000">
2672 <synopsis>Get Stack Trace--Asynchronous</synopsis>
2673 <description>
2674 Get information about the entire stack of a thread (or a sub-section of it).
2675 This is the asynchronous version of <functionlink id="GetStackTrace"></functionlink>
2676 and is reentrant and safe to call
2677 from asynchronous signal handlers.
2678 The stack trace is returned only for the calling thread.
2679 <p/>
2680 The <functionlink id="GetLineNumberTable"></functionlink>
2681 function can be used to map locations to line numbers. Note that
2682 this mapping can be done lazily.
2683 </description>
2684 <origin>jvmpi</origin>
2685 <capabilities>
2686 <required id="can_get_async_stack_trace"></required>
2687 <capability id="can_show_JVM_spec_async_frames">
2688 If <code>false</code>,
2689 <paramlink id="use_java_stack"></paramlink>
2690 must be <code>false</code>.
2691 </capability>
2692 </capabilities>
2693 <parameters>
2694 <param id="use_java_stack">
2695 <jboolean/>
2696 <description>
2697 Return the stack showing <vmspec/>
2698 model of the stack;
2699 otherwise, show the internal representation of the stack with
2700 inlined and optimized methods missing. If the virtual machine
2701 is using the <i>Java Virtual Machine Specification</i> stack model
2702 internally, this flag is ignored.
2703 </description>
2704 </param>
2705 <param id="max_count">
2706 <jint min="0"/>
2707 <description>
2708 The maximum number of <datalink id="jvmtiFrameInfo"/> records to retrieve.
2709 Retrieve this many unless the stack depth is less than <code>max_count</code>.
2710 </description>
2711 </param>
2712 <param id="frame_buffer">
2713 <outbuf incount="max_count" outcount="count_ptr">
2714 <struct>jvmtiFrameInfo</struct>
2715 <nullok>this information is not returned</nullok>
2716 </outbuf>
2717 <description>
2718 The agent passes in a buffer
2719 large enough to hold <code>max_count</code> records of
2720 <datalink id="jvmtiFrameInfo"></datalink>. This buffer must be
2721 pre-allocated by the agent.
2722 </description>
2723 </param>
2724 <param id="count_ptr">
2725 <outptr><jint/></outptr>
2726 <description>
2727 On return, points to the number of records filled in..
2728 </description>
2729 </param>
2730 </parameters>
2731 <errors>
2732 <error id="JVMTI_ERROR_UNATTACHED_THREAD">
2733 The thread being used to call this function is not attached
2734 to the virtual machine. Calls must be made from attached threads.
2735 </error>
2736 </errors>
2737 </function>
2738 </elide>
2739
2740 <function id="GetFrameCount" num="16">
2741 <synopsis>Get Frame Count</synopsis>
2742 <description>
2743 Get the number of frames currently in the specified thread's call stack.
2744 <p/>
2745 If this function is called for a thread actively executing bytecodes (for example,
2746 not the current thread and not suspended), the information returned is transient.
2747 </description>
2748 <origin>jvmdi</origin>
2749 <capabilities>
2750 </capabilities>
2751 <parameters>
2752 <param id="thread">
2753 <jthread null="current"/>
2754 <description>
2755 The thread to query.
2756 </description>
2757 </param>
2758 <param id="count_ptr">
2759 <outptr><jint/></outptr>
2760 <description>
2761 On return, points to the number of frames in the call stack.
2762 </description>
2763 </param>
2764 </parameters>
2765 <errors>
2766 </errors>
2767 </function>
2768
2769 <function id="PopFrame" num="80">
2770 <synopsis>Pop Frame</synopsis>
2771 <description>
2772 Pop the current frame of <code>thread</code>'s stack.
2773 Popping a frame takes you to the previous frame.
2774 When the thread is resumed, the execution
2775 state of the thread is reset to the state
2776 immediately before the called method was invoked.
2777 That is (using <vmspec/> terminology):
2778 <ul>
2779 <li>the current frame is discarded as the previous frame becomes the current one</li>
2780 <li>the operand stack is restored--the argument values are added back
2781 and if the invoke was not <code>invokestatic</code>,
2782 <code>objectref</code> is added back as well</li>
2783 <li>the Java virtual machine PC is restored to the opcode
2784 of the invoke instruction</li>
2785 </ul>
2786 Note however, that any changes to the arguments, which
2787 occurred in the called method, remain;
2788 when execution continues, the first instruction to
2789 execute will be the invoke.
2790 <p/>
2791 Between calling <code>PopFrame</code> and resuming the
2792 thread the state of the stack is undefined.
2793 To pop frames beyond the first,
2794 these three steps must be repeated:
2795 <ul>
2796 <li>suspend the thread via an event (step, breakpoint, ...)</li>
2797 <li>call <code>PopFrame</code></li>
2798 <li>resume the thread</li>
2799 </ul>
2800 <p/>
2801 A lock acquired by calling the called method
2802 (if it is a <code>synchronized</code> method)
2803 and locks acquired by entering <code>synchronized</code>
2804 blocks within the called method are released.
2805 Note: this does not apply to native locks or
2806 <code>java.util.concurrent.locks</code> locks.
2807 <p/>
2808 Finally blocks are not executed.
2809 <p/>
2810 Changes to global state are not addressed and thus remain changed.
2811 <p/>
2812 The specified thread must be suspended (which implies it cannot be the current thread).
2813 <p/>
2814 Both the called method and calling method must be non-native Java programming
2815 language methods.
2816 <p/>
2817 No <jvmti/> events are generated by this function.
2818 </description>
2819 <origin>jvmdi</origin>
2820 <capabilities>
2821 <required id="can_pop_frame"></required>
2822 </capabilities>
2823 <parameters>
2824 <param id="thread">
2825 <jthread/>
2826 <description>
2827 The thread whose current frame is to be popped.
2828 </description>
2829 </param>
2830 </parameters>
2831 <errors>
2832 <error id="JVMTI_ERROR_OPAQUE_FRAME">
2833 Called or calling method is a native method.
2834 The implementation is unable to pop this frame.
2835 </error>
2836 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
2837 Thread was not suspended.
2838 </error>
2839 <error id="JVMTI_ERROR_NO_MORE_FRAMES">
2840 There are less than two stack frames on the call stack.
2841 </error>
2842 </errors>
2843 </function>
2844
2845 <function id="GetFrameLocation" num="19">
2846 <synopsis>Get Frame Location</synopsis>
2847 <description>
2848 <p/>
2849 For a Java programming language frame, return the location of the instruction
2850 currently executing.
2851 </description>
2852 <origin>jvmdiClone</origin>
2853 <capabilities>
2854 </capabilities>
2855 <parameters>
2856 <param id="thread">
2857 <jthread null="current" frame="frame"/>
2858 <description>
2859 The thread of the frame to query.
2860 </description>
2861 </param>
2862 <param id="depth">
2863 <jframeID thread="thread"/>
2864 <description>
2865 The depth of the frame to query.
2866 </description>
2867 </param>
2868 <param id="method_ptr">
2869 <outptr><jmethodID/></outptr>
2870 <description>
2871 On return, points to the method for the current location.
2872 </description>
2873 </param>
2874 <param id="location_ptr">
2875 <outptr><jlocation/></outptr>
2876 <description>
2877 On return, points to the index of the currently
2878 executing instruction.
2879 Is set to <code>-1</code> if the frame is executing
2880 a native method.
2881 </description>
2882 </param>
2883 </parameters>
2884 <errors>
2885 </errors>
2886 </function>
2887
2888 <function id="NotifyFramePop" num="20">
2889 <synopsis>Notify Frame Pop</synopsis>
2890 <description>
2891 When the frame that is currently at <paramlink id="depth"></paramlink>
2892 is popped from the stack, generate a
2893 <eventlink id="FramePop"></eventlink> event. See the
2894 <eventlink id="FramePop"></eventlink> event for details.
2895 Only frames corresponding to non-native Java programming language
2896 methods can receive notification.
2897 <p/>
2898 The specified thread must either be the current thread
2899 or the thread must be suspended.
2900 </description>
2901 <origin>jvmdi</origin>
2902 <capabilities>
2903 <required id="can_generate_frame_pop_events"></required>
2904 </capabilities>
2905 <parameters>
2906 <param id="thread">
2907 <jthread null="current" frame="depth"/>
2908 <description>
2909 The thread of the frame for which the frame pop event will be generated.
2910 </description>
2911 </param>
2912 <param id="depth">
2913 <jframeID thread="thread"/>
2914 <description>
2915 The depth of the frame for which the frame pop event will be generated.
2916 </description>
2917 </param>
2918 </parameters>
2919 <errors>
2920 <error id="JVMTI_ERROR_OPAQUE_FRAME">
2921 The frame at <code>depth</code> is executing a
2922 native method.
2923 </error>
2924 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
2925 Thread was not suspended and was not the current thread.
2926 </error>
2927 </errors>
2928 </function>
2929
2930 </category>
2931
2932 <category id="ForceEarlyReturn" label="Force Early Return">
2933 <intro>
2934 These functions allow an agent to force a method
2935 to return at any point during its execution.
2936 The method which will return early is referred to as the <i>called method</i>.
2937 The called method is the current method
2938 (as defined by
2939 <vmspec chapter="3.6"/>)
2940 for the specified thread at
2941 the time the function is called.
2942 <p/>
2943 The specified thread must be suspended or must be the current thread.
2944 The return occurs when execution of Java programming
2945 language code is resumed on this thread.
2946 Between calling one of these functions and resumption
2947 of thread execution, the state of the stack is undefined.
2948 <p/>
2949 No further instructions are executed in the called method.
2950 Specifically, finally blocks are not executed.
2951 Note: this can cause inconsistent states in the application.
2952 <p/>
2953 A lock acquired by calling the called method
2954 (if it is a <code>synchronized</code> method)
2955 and locks acquired by entering <code>synchronized</code>
2956 blocks within the called method are released.
2957 Note: this does not apply to native locks or
2958 <code>java.util.concurrent.locks</code> locks.
2959 <p/>
2960 Events, such as <eventlink id="MethodExit"></eventlink>,
2961 are generated as they would be in a normal return.
2962 <p/>
2963 The called method must be a non-native Java programming
2964 language method.
2965 Forcing return on a thread with only one frame on the
2966 stack causes the thread to exit when resumed.
2967 </intro>
2968
2969 <function id="ForceEarlyReturnObject" num="81" since="1.1">
2970 <synopsis>Force Early Return - Object</synopsis>
2971 <description>
2972 This function can be used to return from a method whose
2973 result type is <code>Object</code>
2974 or a subclass of <code>Object</code>.
2975 </description>
2976 <origin>new</origin>
2977 <capabilities>
2978 <required id="can_force_early_return"></required>
2979 </capabilities>
2980 <parameters>
2981 <param id="thread">
2982 <jthread null="current"/>
2983 <description>
2984 The thread whose current frame is to return early.
2985 </description>
2986 </param>
2987 <param id="value">
2988 <jobject/>
2989 <description>
2990 The return value for the called frame.
2991 An object or <code>NULL</code>.
2992 </description>
2993 </param>
2994 </parameters>
2995 <errors>
2996 <error id="JVMTI_ERROR_OPAQUE_FRAME">
2997 Attempted to return early from a frame
2998 corresponding to a native method.
2999 Or the implementation is unable to provide
3000 this functionality on this frame.
3001 </error>
3002 <error id="JVMTI_ERROR_TYPE_MISMATCH">
3003 The result type of the called method is not
3004 <code>Object</code> or a subclass of <code>Object</code>.
3005 </error>
3006 <error id="JVMTI_ERROR_TYPE_MISMATCH">
3007 The supplied <paramlink id="value"/> is not compatible with the
3008 result type of the called method.
3009 </error>
3010 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
3011 Thread was not the current thread and was not suspended.
3012 </error>
3013 <error id="JVMTI_ERROR_NO_MORE_FRAMES">
3014 There are no more frames on the call stack.
3015 </error>
3016 </errors>
3017 </function>
3018
3019 <function id="ForceEarlyReturnInt" num="82" since="1.1">
3020 <synopsis>Force Early Return - Int</synopsis>
3021 <description>
3022 This function can be used to return from a method whose
3023 result type is <code>int</code>, <code>short</code>,
3024 <code>char</code>, <code>byte</code>, or
3025 <code>boolean</code>.
3026 </description>
3027 <origin>new</origin>
3028 <capabilities>
3029 <required id="can_force_early_return"></required>
3030 </capabilities>
3031 <parameters>
3032 <param id="thread">
3033 <jthread null="current"/>
3034 <description>
3035 The thread whose current frame is to return early.
3036 </description>
3037 </param>
3038 <param id="value">
3039 <jint/>
3040 <description>
3041 The return value for the called frame.
3042 </description>
3043 </param>
3044 </parameters>
3045 <errors>
3046 <error id="JVMTI_ERROR_OPAQUE_FRAME">
3047 Attempted to return early from a frame
3048 corresponding to a native method.
3049 Or the implementation is unable to provide
3050 this functionality on this frame.
3051 </error>
3052 <error id="JVMTI_ERROR_TYPE_MISMATCH">
3053 The result type of the called method is not
3054 <code>int</code>, <code>short</code>,
3055 <code>char</code>, <code>byte</code>, or
3056 <code>boolean</code>.
3057 </error>
3058 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
3059 Thread was not the current thread and was not suspended.
3060 </error>
3061 <error id="JVMTI_ERROR_NO_MORE_FRAMES">
3062 There are no frames on the call stack.
3063 </error>
3064 </errors>
3065 </function>
3066
3067 <function id="ForceEarlyReturnLong" num="83" since="1.1">
3068 <synopsis>Force Early Return - Long</synopsis>
3069 <description>
3070 This function can be used to return from a method whose
3071 result type is <code>long</code>.
3072 </description>
3073 <origin>new</origin>
3074 <capabilities>
3075 <required id="can_force_early_return"></required>
3076 </capabilities>
3077 <parameters>
3078 <param id="thread">
3079 <jthread null="current"/>
3080 <description>
3081 The thread whose current frame is to return early.
3082 </description>
3083 </param>
3084 <param id="value">
3085 <jlong/>
3086 <description>
3087 The return value for the called frame.
3088 </description>
3089 </param>
3090 </parameters>
3091 <errors>
3092 <error id="JVMTI_ERROR_OPAQUE_FRAME">
3093 Attempted to return early from a frame
3094 corresponding to a native method.
3095 Or the implementation is unable to provide
3096 this functionality on this frame.
3097 </error>
3098 <error id="JVMTI_ERROR_TYPE_MISMATCH">
3099 The result type of the called method is not <code>long</code>.
3100 </error>
3101 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
3102 Thread was not the current thread and was not suspended.
3103 </error>
3104 <error id="JVMTI_ERROR_NO_MORE_FRAMES">
3105 There are no frames on the call stack.
3106 </error>
3107 </errors>
3108 </function>
3109
3110 <function id="ForceEarlyReturnFloat" num="84" since="1.1">
3111 <synopsis>Force Early Return - Float</synopsis>
3112 <description>
3113 This function can be used to return from a method whose
3114 result type is <code>float</code>.
3115 </description>
3116 <origin>new</origin>
3117 <capabilities>
3118 <required id="can_force_early_return"></required>
3119 </capabilities>
3120 <parameters>
3121 <param id="thread">
3122 <jthread null="current"/>
3123 <description>
3124 The thread whose current frame is to return early.
3125 </description>
3126 </param>
3127 <param id="value">
3128 <jfloat/>
3129 <description>
3130 The return value for the called frame.
3131 </description>
3132 </param>
3133 </parameters>
3134 <errors>
3135 <error id="JVMTI_ERROR_OPAQUE_FRAME">
3136 Attempted to return early from a frame
3137 corresponding to a native method.
3138 Or the implementation is unable to provide
3139 this functionality on this frame.
3140 </error>
3141 <error id="JVMTI_ERROR_TYPE_MISMATCH">
3142 The result type of the called method is not <code>float</code>.
3143 </error>
3144 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
3145 Thread was not the current thread and was not suspended.
3146 </error>
3147 <error id="JVMTI_ERROR_NO_MORE_FRAMES">
3148 There are no frames on the call stack.
3149 </error>
3150 </errors>
3151 </function>
3152
3153 <function id="ForceEarlyReturnDouble" num="85" since="1.1">
3154 <synopsis>Force Early Return - Double</synopsis>
3155 <description>
3156 This function can be used to return from a method whose
3157 result type is <code>double</code>.
3158 </description>
3159 <origin>new</origin>
3160 <capabilities>
3161 <required id="can_force_early_return"></required>
3162 </capabilities>
3163 <parameters>
3164 <param id="thread">
3165 <jthread null="current"/>
3166 <description>
3167 The thread whose current frame is to return early.
3168 </description>
3169 </param>
3170 <param id="value">
3171 <jdouble/>
3172 <description>
3173 The return value for the called frame.
3174 </description>
3175 </param>
3176 </parameters>
3177 <errors>
3178 <error id="JVMTI_ERROR_OPAQUE_FRAME">
3179 Attempted to return early from a frame corresponding to a native method.
3180 Or the implementation is unable to provide this functionality on this frame.
3181 </error>
3182 <error id="JVMTI_ERROR_TYPE_MISMATCH">
3183 The result type of the called method is not <code>double</code>.
3184 </error>
3185 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
3186 Thread was not the current thread and was not suspended.
3187 </error>
3188 <error id="JVMTI_ERROR_NO_MORE_FRAMES">
3189 There are no frames on the call stack.
3190 </error>
3191 </errors>
3192 </function>
3193
3194 <function id="ForceEarlyReturnVoid" num="86" since="1.1">
3195 <synopsis>Force Early Return - Void</synopsis>
3196 <description>
3197 This function can be used to return from a method with no result type.
3198 That is, the called method must be declared <code>void</code>.
3199 </description>
3200 <origin>new</origin>
3201 <capabilities>
3202 <required id="can_force_early_return"></required>
3203 </capabilities>
3204 <parameters>
3205 <param id="thread">
3206 <jthread null="current"/>
3207 <description>
3208 The thread whose current frame is to return early.
3209 </description>
3210 </param>
3211 </parameters>
3212 <errors>
3213 <error id="JVMTI_ERROR_OPAQUE_FRAME">
3214 Attempted to return early from a frame
3215 corresponding to a native method.
3216 Or the implementation is unable to provide
3217 this functionality on this frame.
3218 </error>
3219 <error id="JVMTI_ERROR_TYPE_MISMATCH">
3220 The called method has a result type.
3221 </error>
3222 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
3223 Thread was not the current thread and was not suspended.
3224 </error>
3225 <error id="JVMTI_ERROR_NO_MORE_FRAMES">
3226 There are no frames on the call stack.
3227 </error>
3228 </errors>
3229 </function>
3230
3231 </category>
3232
3233 <category id="Heap" label="Heap">
3234 <intro>
3235 These functions are used to analyze the heap.
3236 Functionality includes the ability to view the objects in the
3237 heap and to tag these objects.
3238 </intro>
3239
3240 <intro id="objectTags" label="Object Tags">
3241 A <i>tag</i> is a value associated with an object.
3242 Tags are explicitly set by the agent using the
3243 <functionlink id="SetTag"></functionlink> function or by
3244 callback functions such as <functionlink id="jvmtiHeapIterationCallback"/>.
3245 <p/>
3246 Tags are local to the environment; that is, the tags of one
3247 environment are not visible in another.
3248 <p/>
3249 Tags are <code>jlong</code> values which can be used
3250 simply to mark an object or to store a pointer to more detailed
3251 information. Objects which have not been tagged have a
3252 tag of zero.
3253 Setting a tag to zero makes the object untagged.
3254 </intro>
3255
3256 <intro id="heapCallbacks" label="Heap Callback Functions">
3257 Heap functions which iterate through the heap and recursively
3258 follow object references use agent supplied callback functions
3259 to deliver the information.
3260 <p/>
3261 These heap callback functions must adhere to the following restrictions --
3262 These callbacks must not use JNI functions.
3263 These callbacks must not use <jvmti/> functions except
3264 <i>callback safe</i> functions which
3265 specifically allow such use (see the raw monitor, memory management,
3266 and environment local storage functions).
3267 <p/>
3268 An implementation may invoke a callback on an internal thread or
3269 the thread which called the iteration function.
3270 Heap callbacks are single threaded -- no more than one callback will
3271 be invoked at a time.
3272 <p/>
3273 The Heap Filter Flags can be used to prevent reporting
3274 based on the tag status of an object or its class.
3275 If no flags are set (the <code>jint</code> is zero), objects
3276 will not be filtered out.
3277
3278 <constants id="jvmtiHeapFilter" label="Heap Filter Flags" kind="bits">
3279 <constant id="JVMTI_HEAP_FILTER_TAGGED" num="0x4">
3280 Filter out tagged objects. Objects which are tagged are not included.
3281 </constant>
3282 <constant id="JVMTI_HEAP_FILTER_UNTAGGED" num="0x8">
3283 Filter out untagged objects. Objects which are not tagged are not included.
3284 </constant>
3285 <constant id="JVMTI_HEAP_FILTER_CLASS_TAGGED" num="0x10">
3286 Filter out objects with tagged classes. Objects whose class is tagged are not included.
3287 </constant>
3288 <constant id="JVMTI_HEAP_FILTER_CLASS_UNTAGGED" num="0x20">
3289 Filter out objects with untagged classes. Objects whose class is not tagged are not included.
3290 </constant>
3291 </constants>
3292
3293 <p/>
3294 The Heap Visit Control Flags are returned by the heap callbacks
3295 and can be used to abort the iteration. For the
3296 <functionlink id="jvmtiHeapReferenceCallback">Heap
3297 Reference Callback</functionlink>, it can also be used
3298 to prune the graph of traversed references
3299 (<code>JVMTI_VISIT_OBJECTS</code> is not set).
3300
3301 <constants id="jvmtiHeapVisitControl"
3302 label="Heap Visit Control Flags"
3303 kind="bits"
3304 since="1.1">
3305 <constant id="JVMTI_VISIT_OBJECTS" num="0x100">
3306 If we are visiting an object and if this callback
3307 was initiated by <functionlink id="FollowReferences"/>,
3308 traverse the references of this object.
3309 Otherwise ignored.
3310 </constant>
3311 <constant id="JVMTI_VISIT_ABORT" num="0x8000">
3312 Abort the iteration. Ignore all other bits.
3313 </constant>
3314 </constants>
3315
3316 <p/>
3317 The Heap Reference Enumeration is provided by the
3318 <functionlink id="jvmtiHeapReferenceCallback">Heap
3319 Reference Callback</functionlink> and
3320 <functionlink id="jvmtiPrimitiveFieldCallback">Primitive Field
3321 Callback</functionlink> to
3322 describe the kind of reference
3323 being reported.
3324
3325 <constants id="jvmtiHeapReferenceKind"
3326 label="Heap Reference Enumeration"
3327 kind="enum"
3328 since="1.1">
3329 <constant id="JVMTI_HEAP_REFERENCE_CLASS" num="1">
3330 Reference from an object to its class.
3331 </constant>
3332 <constant id="JVMTI_HEAP_REFERENCE_FIELD" num="2">
3333 Reference from an object to the value of one of its instance fields.
3334 </constant>
3335 <constant id="JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT" num="3">
3336 Reference from an array to one of its elements.
3337 </constant>
3338 <constant id="JVMTI_HEAP_REFERENCE_CLASS_LOADER" num="4">
3339 Reference from a class to its class loader.
3340 </constant>
3341 <constant id="JVMTI_HEAP_REFERENCE_SIGNERS" num="5">
3342 Reference from a class to its signers array.
3343 </constant>
3344 <constant id="JVMTI_HEAP_REFERENCE_PROTECTION_DOMAIN" num="6">
3345 Reference from a class to its protection domain.
3346 </constant>
3347 <constant id="JVMTI_HEAP_REFERENCE_INTERFACE" num="7">
3348 Reference from a class to one of its interfaces.
3349 Note: interfaces are defined via a constant pool reference,
3350 so the referenced interfaces may also be reported with a
3351 <code>JVMTI_HEAP_REFERENCE_CONSTANT_POOL</code> reference kind.
3352 </constant>
3353 <constant id="JVMTI_HEAP_REFERENCE_STATIC_FIELD" num="8">
3354 Reference from a class to the value of one of its static fields.
3355 </constant>
3356 <constant id="JVMTI_HEAP_REFERENCE_CONSTANT_POOL" num="9">
3357 Reference from a class to a resolved entry in the constant pool.
3358 </constant>
3359 <constant id="JVMTI_HEAP_REFERENCE_SUPERCLASS" num="10">
3360 Reference from a class to its superclass.
3361 A callback is bot sent if the superclass is <code>java.lang.Object</code>.
3362 Note: loaded classes define superclasses via a constant pool
3363 reference, so the referenced superclass may also be reported with
3364 a <code>JVMTI_HEAP_REFERENCE_CONSTANT_POOL</code> reference kind.
3365 </constant>
3366 <constant id="JVMTI_HEAP_REFERENCE_JNI_GLOBAL" num="21">
3367 Heap root reference: JNI global reference.
3368 </constant>
3369 <constant id="JVMTI_HEAP_REFERENCE_SYSTEM_CLASS" num="22">
3370 Heap root reference: System class.
3371 </constant>
3372 <constant id="JVMTI_HEAP_REFERENCE_MONITOR" num="23">
3373 Heap root reference: monitor.
3374 </constant>
3375 <constant id="JVMTI_HEAP_REFERENCE_STACK_LOCAL" num="24">
3376 Heap root reference: local variable on the stack.
3377 </constant>
3378 <constant id="JVMTI_HEAP_REFERENCE_JNI_LOCAL" num="25">
3379 Heap root reference: JNI local reference.
3380 </constant>
3381 <constant id="JVMTI_HEAP_REFERENCE_THREAD" num="26">
3382 Heap root reference: Thread.
3383 </constant>
3384 <constant id="JVMTI_HEAP_REFERENCE_OTHER" num="27">
3385 Heap root reference: other heap root reference.
3386 </constant>
3387 </constants>
3388
3389 <p/>
3390 Definitions for the single character type descriptors of
3391 primitive types.
3392
3393 <constants id="jvmtiPrimitiveType"
3394 label="Primitive Type Enumeration"
3395 kind="enum"
3396 since="1.1">
3397 <constant id="JVMTI_PRIMITIVE_TYPE_BOOLEAN" num="90">
3398 'Z' - Java programming language <code>boolean</code> - JNI <code>jboolean</code>
3399 </constant>
3400 <constant id="JVMTI_PRIMITIVE_TYPE_BYTE" num="66">
3401 'B' - Java programming language <code>byte</code> - JNI <code>jbyte</code>
3402 </constant>
3403 <constant id="JVMTI_PRIMITIVE_TYPE_CHAR" num="67">
3404 'C' - Java programming language <code>char</code> - JNI <code>jchar</code>
3405 </constant>
3406 <constant id="JVMTI_PRIMITIVE_TYPE_SHORT" num="83">
3407 'S' - Java programming language <code>short</code> - JNI <code>jshort</code>
3408 </constant>
3409 <constant id="JVMTI_PRIMITIVE_TYPE_INT" num="73">
3410 'I' - Java programming language <code>int</code> - JNI <code>jint</code>
3411 </constant>
3412 <constant id="JVMTI_PRIMITIVE_TYPE_LONG" num="74">
3413 'J' - Java programming language <code>long</code> - JNI <code>jlong</code>
3414 </constant>
3415 <constant id="JVMTI_PRIMITIVE_TYPE_FLOAT" num="70">
3416 'F' - Java programming language <code>float</code> - JNI <code>jfloat</code>
3417 </constant>
3418 <constant id="JVMTI_PRIMITIVE_TYPE_DOUBLE" num="68">
3419 'D' - Java programming language <code>double</code> - JNI <code>jdouble</code>
3420 </constant>
3421 </constants>
3422 </intro>
3423
3424 <typedef id="jvmtiHeapReferenceInfoField"
3425 label="Reference information structure for Field references"
3426 since="1.1">
3427 <description>
3428 Reference information returned for
3429 <datalink id="JVMTI_HEAP_REFERENCE_FIELD"/> and
3430 <datalink id="JVMTI_HEAP_REFERENCE_STATIC_FIELD"/> references.
3431 </description>
3432 <field id="index">
3433 <jint/>
3434 <description>
3435 For <datalink id="JVMTI_HEAP_REFERENCE_FIELD"/>, the
3436 referrer object is not a class or an inteface.
3437 In this case, <code>index</code> is the index of the field
3438 in the class of the referrer object.
3439 This class is referred to below as <i>C</i>.
3440 <p/>
3441 For <datalink id="JVMTI_HEAP_REFERENCE_STATIC_FIELD"/>,
3442 the referrer object is a class (referred to below as <i>C</i>)
3443 or an interface (referred to below as <i>I</i>).
3444 In this case, <code>index</code> is the index of the field in
3445 that class or interface.
3446 <p/>
3447 If the referrer object is not an interface, then the field
3448 indices are determined as follows:
3449 <ul>
3450 <li>make a list of all the fields in <i>C</i> and its
3451 superclasses, starting with all the fields in
3452 <code>java.lang.Object</code> and ending with all the
3453 fields in <i>C</i>.</li>
3454 <li>Within this list, put
3455 the fields for a given class in the order returned by
3456 <functionlink id="GetClassFields"/>.</li>
3457 <li>Assign the fields in this list indices
3458 <i>n</i>, <i>n</i>+1, ..., in order, where <i>n</i>
3459 is the count of the fields in all the interfaces
3460 implemented by <i>C</i>.
3461 Note that <i>C</i> implements all interfaces
3462 directly implemented by its superclasses; as well
3463 as all superinterfaces of these interfaces.</li>
3464 </ul>
3465 If the referrer object is an interface, then the field
3466 indices are determined as follows:
3467 <ul>
3468 <li>make a list of the fields directly declared in
3469 <i>I</i>.</li>
3470 <li>Within this list, put
3471 the fields in the order returned by
3472 <functionlink id="GetClassFields"/>.</li>
3473 <li>Assign the fields in this list indices
3474 <i>n</i>, <i>n</i>+1, ..., in order, where <i>n</i>
3475 is the count of the fields in all the superinterfaces
3476 of <i>I</i>.</li>
3477 </ul>
3478 All fields are included in this computation, regardless of
3479 field modifier (static, public, private, etc).
3480 <p/>
3481 For example, given the following classes and interfaces:
3482 <example>
3483 interface I0 {
3484 int p = 0;
3485 }
3486
3487 interface I1 extends I0 {
3488 int x = 1;
3489 }
3490
3491 interface I2 extends I0 {
3492 int y = 2;
3493 }
3494
3495 class C1 implements I1 {
3496 public static int a = 3;
3497 private int b = 4;
3498 }
3499
3500 class C2 extends C1 implements I2 {
3501 static int q = 5;
3502 final int r = 6;
3503 }
3504 </example>
3505 Assume that <functionlink id="GetClassFields"/> called on
3506 <code>C1</code> returns the fields of <code>C1</code> in the
3507 order: a, b; and that the fields of <code>C2</code> are
3508 returned in the order: q, r.
3509 An instance of class <code>C1</code> will have the
3510 following field indices:
3511 <dl><dd><table>
3512 <tr>
3513 <td>
3514 a
3515 </td>
3516 <td>
3517 2
3518 </td>
3519 <td align="left">
3520 The count of the fields in the interfaces
3521 implemented by <code>C1</code> is two (<i>n</i>=2):
3522 <code>p</code> of <code>I0</code>
3523 and <code>x</code> of <code>I1</code>.
3524 </td>
3525 </tr>
3526 <tr>
3527 <td>
3528 b
3529 </td>
3530 <td>
3531 3
3532 </td>
3533 <td align="left">
3534 the subsequent index.
3535 </td>
3536 </tr>
3537 </table></dd></dl>
3538 The class <code>C1</code> will have the same field indices.
3539 <p/>
3540 An instance of class <code>C2</code> will have the
3541 following field indices:
3542 <dl><dd><table>
3543 <tr>
3544 <td>
3545 a
3546 </td>
3547 <td>
3548 3
3549 </td>
3550 <td align="left">
3551 The count of the fields in the interfaces
3552 implemented by <code>C2</code> is three (<i>n</i>=3):
3553 <code>p</code> of <code>I0</code>,
3554 <code>x</code> of <code>I1</code> and <code>y</code> of <code>I2</code>
3555 (an interface of <code>C2</code>). Note that the field <code>p</code>
3556 of <code>I0</code> is only included once.
3557 </td>
3558 </tr>
3559 <tr>
3560 <td>
3561 b
3562 </td>
3563 <td>
3564 4
3565 </td>
3566 <td align="left">
3567 the subsequent index to "a".
3568 </td>
3569 </tr>
3570 <tr>
3571 <td>
3572 q
3573 </td>
3574 <td>
3575 5
3576 </td>
3577 <td align="left">
3578 the subsequent index to "b".
3579 </td>
3580 </tr>
3581 <tr>
3582 <td>
3583 r
3584 </td>
3585 <td>
3586 6
3587 </td>
3588 <td align="left">
3589 the subsequent index to "q".
3590 </td>
3591 </tr>
3592 </table></dd></dl>
3593 The class <code>C2</code> will have the same field indices.
3594 Note that a field may have a different index depending on the
3595 object that is viewing it -- for example field "a" above.
3596 Note also: not all field indices may be visible from the
3597 callbacks, but all indices are shown for illustrative purposes.
3598 <p/>
3599 The interface <code>I1</code> will have the
3600 following field indices:
3601 <dl><dd><table>
3602 <tr>
3603 <td>
3604 x
3605 </td>
3606 <td>
3607 1
3608 </td>
3609 <td align="left">
3610 The count of the fields in the superinterfaces
3611 of <code>I1</code> is one (<i>n</i>=1):
3612 <code>p</code> of <code>I0</code>.
3613 </td>
3614 </tr>
3615 </table></dd></dl>
3616 </description>
3617 </field>
3618 </typedef>
3619
3620 <typedef id="jvmtiHeapReferenceInfoArray"
3621 label="Reference information structure for Array references"
3622 since="1.1">
3623 <description>
3624 Reference information returned for
3625 <datalink id="JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT"/> references.
3626 </description>
3627 <field id="index">
3628 <jint/>
3629 <description>
3630 The array index.
3631 </description>
3632 </field>
3633 </typedef>
3634
3635 <typedef id="jvmtiHeapReferenceInfoConstantPool"
3636 label="Reference information structure for Constant Pool references"
3637 since="1.1">
3638 <description>
3639 Reference information returned for
3640 <datalink id="JVMTI_HEAP_REFERENCE_CONSTANT_POOL"/> references.
3641 </description>
3642 <field id="index">
3643 <jint/>
3644 <description>
3645 The index into the constant pool of the class. See the description in
3646 <vmspec chapter="4.4"/>.
3647 </description>
3648 </field>
3649 </typedef>
3650
3651 <typedef id="jvmtiHeapReferenceInfoStackLocal"
3652 label="Reference information structure for Local Variable references"
3653 since="1.1">
3654 <description>
3655 Reference information returned for
3656 <datalink id="JVMTI_HEAP_REFERENCE_STACK_LOCAL"/> references.
3657 </description>
3658 <field id="thread_tag">
3659 <jlong/>
3660 <description>
3661 The tag of the thread corresponding to this stack, zero if not tagged.
3662 </description>
3663 </field>
3664 <field id="thread_id">
3665 <jlong/>
3666 <description>
3667 The unique thread ID of the thread corresponding to this stack.
3668 </description>
3669 </field>
3670 <field id="depth">
3671 <jint/>
3672 <description>
3673 The depth of the frame.
3674 </description>
3675 </field>
3676 <field id="method">
3677 <jmethodID/>
3678 <description>
3679 The method executing in this frame.
3680 </description>
3681 </field>
3682 <field id="location">
3683 <jlocation/>
3684 <description>
3685 The currently executing location in this frame.
3686 </description>
3687 </field>
3688 <field id="slot">
3689 <jint/>
3690 <description>
3691 The slot number of the local variable.
3692 </description>
3693 </field>
3694 </typedef>
3695
3696 <typedef id="jvmtiHeapReferenceInfoJniLocal"
3697 label="Reference information structure for JNI local references"
3698 since="1.1">
3699 <description>
3700 Reference information returned for
3701 <datalink id="JVMTI_HEAP_REFERENCE_JNI_LOCAL"/> references.
3702 </description>
3703 <field id="thread_tag">
3704 <jlong/>
3705 <description>
3706 The tag of the thread corresponding to this stack, zero if not tagged.
3707 </description>
3708 </field>
3709 <field id="thread_id">
3710 <jlong/>
3711 <description>
3712 The unique thread ID of the thread corresponding to this stack.
3713 </description>
3714 </field>
3715 <field id="depth">
3716 <jint/>
3717 <description>
3718 The depth of the frame.
3719 </description>
3720 </field>
3721 <field id="method">
3722 <jmethodID/>
3723 <description>
3724 The method executing in this frame.
3725 </description>
3726 </field>
3727 </typedef>
3728
3729 <typedef id="jvmtiHeapReferenceInfoReserved"
3730 label="Reference information structure for Other references"
3731 since="1.1">
3732 <description>
3733 Reference information returned for other references.
3734 </description>
3735 <field id="reserved1">
3736 <jlong/>
3737 <description>
3738 reserved for future use.
3739 </description>
3740 </field>
3741 <field id="reserved2">
3742 <jlong/>
3743 <description>
3744 reserved for future use.
3745 </description>
3746 </field>
3747 <field id="reserved3">
3748 <jlong/>
3749 <description>
3750 reserved for future use.
3751 </description>
3752 </field>
3753 <field id="reserved4">
3754 <jlong/>
3755 <description>
3756 reserved for future use.
3757 </description>
3758 </field>
3759 <field id="reserved5">
3760 <jlong/>
3761 <description>
3762 reserved for future use.
3763 </description>
3764 </field>
3765 <field id="reserved6">
3766 <jlong/>
3767 <description>
3768 reserved for future use.
3769 </description>
3770 </field>
3771 <field id="reserved7">
3772 <jlong/>
3773 <description>
3774 reserved for future use.
3775 </description>
3776 </field>
3777 <field id="reserved8">
3778 <jlong/>
3779 <description>
3780 reserved for future use.
3781 </description>
3782 </field>
3783 </typedef>
3784
3785 <uniontypedef id="jvmtiHeapReferenceInfo"
3786 label="Reference information structure"
3787 since="1.1">
3788 <description>
3789 The information returned about referrers.
3790 Represented as a union of the various kinds of reference information.
3791 </description>
3792 <field id="field">
3793 <struct>jvmtiHeapReferenceInfoField</struct>
3794 <description>
3795 The referrer information for
3796 <datalink id="JVMTI_HEAP_REFERENCE_FIELD"/>
3797 and <datalink id="JVMTI_HEAP_REFERENCE_STATIC_FIELD"/> references.
3798 </description>
3799 </field>
3800 <field id="array">
3801 <struct>jvmtiHeapReferenceInfoArray</struct>
3802 <description>
3803 The referrer information for
3804 For <datalink id="JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT"/> references.
3805 </description>
3806 </field>
3807 <field id="constant_pool">
3808 <struct>jvmtiHeapReferenceInfoConstantPool</struct>
3809 <description>
3810 The referrer information for
3811 For <datalink id="JVMTI_HEAP_REFERENCE_CONSTANT_POOL"/> references.
3812 </description>
3813 </field>
3814 <field id="stack_local">
3815 <struct>jvmtiHeapReferenceInfoStackLocal</struct>
3816 <description>
3817 The referrer information for
3818 For <datalink id="JVMTI_HEAP_REFERENCE_STACK_LOCAL"/> references.
3819 </description>
3820 </field>
3821 <field id="jni_local">
3822 <struct>jvmtiHeapReferenceInfoJniLocal</struct>
3823 <description>
3824 The referrer information for
3825 For <datalink id="JVMTI_HEAP_REFERENCE_JNI_LOCAL"/> references.
3826 </description>
3827 </field>
3828 <field id="other">
3829 <struct>jvmtiHeapReferenceInfoReserved</struct>
3830 <description>
3831 reserved for future use.
3832 </description>
3833 </field>
3834 </uniontypedef>
3835
3836 <typedef id="jvmtiHeapCallbacks"
3837 label="Heap callback function structure"
3838 since="1.1">
3839 <field id="heap_iteration_callback">
3840 <ptrtype>
3841 <struct>jvmtiHeapIterationCallback</struct>
3842 </ptrtype>
3843 <description>
3844 The callback to be called to describe an
3845 object in the heap. Used by the
3846 <functionlink id="IterateThroughHeap"/> function, ignored by the
3847 <functionlink id="FollowReferences"/> function.
3848 </description>
3849 </field>
3850 <field id="heap_reference_callback">
3851 <ptrtype>
3852 <struct>jvmtiHeapReferenceCallback</struct>
3853 </ptrtype>
3854 <description>
3855 The callback to be called to describe an
3856 object reference. Used by the
3857 <functionlink id="FollowReferences"/> function, ignored by the
3858 <functionlink id="IterateThroughHeap"/> function.
3859 </description>
3860 </field>
3861 <field id="primitive_field_callback">
3862 <ptrtype>
3863 <struct>jvmtiPrimitiveFieldCallback</struct>
3864 </ptrtype>
3865 <description>
3866 The callback to be called to describe a
3867 primitive field.
3868 </description>
3869 </field>
3870 <field id="array_primitive_value_callback">
3871 <ptrtype>
3872 <struct>jvmtiArrayPrimitiveValueCallback</struct>
3873 </ptrtype>
3874 <description>
3875 The callback to be called to describe an
3876 array of primitive values.
3877 </description>
3878 </field>
3879 <field id="string_primitive_value_callback">
3880 <ptrtype>
3881 <struct>jvmtiStringPrimitiveValueCallback</struct>
3882 </ptrtype>
3883 <description>
3884 The callback to be called to describe a String value.
3885 </description>
3886 </field>
3887 <field id="reserved5">
3888 <ptrtype>
3889 <struct>jvmtiReservedCallback</struct>
3890 </ptrtype>
3891 <description>
3892 Reserved for future use..
3893 </description>
3894 </field>
3895 <field id="reserved6">
3896 <ptrtype>
3897 <struct>jvmtiReservedCallback</struct>
3898 </ptrtype>
3899 <description>
3900 Reserved for future use..
3901 </description>
3902 </field>
3903 <field id="reserved7">
3904 <ptrtype>
3905 <struct>jvmtiReservedCallback</struct>
3906 </ptrtype>
3907 <description>
3908 Reserved for future use..
3909 </description>
3910 </field>
3911 <field id="reserved8">
3912 <ptrtype>
3913 <struct>jvmtiReservedCallback</struct>
3914 </ptrtype>
3915 <description>
3916 Reserved for future use..
3917 </description>
3918 </field>
3919 <field id="reserved9">
3920 <ptrtype>
3921 <struct>jvmtiReservedCallback</struct>
3922 </ptrtype>
3923 <description>
3924 Reserved for future use..
3925 </description>
3926 </field>
3927 <field id="reserved10">
3928 <ptrtype>
3929 <struct>jvmtiReservedCallback</struct>
3930 </ptrtype>
3931 <description>
3932 Reserved for future use..
3933 </description>
3934 </field>
3935 <field id="reserved11">
3936 <ptrtype>
3937 <struct>jvmtiReservedCallback</struct>
3938 </ptrtype>
3939 <description>
3940 Reserved for future use..
3941 </description>
3942 </field>
3943 <field id="reserved12">
3944 <ptrtype>
3945 <struct>jvmtiReservedCallback</struct>
3946 </ptrtype>
3947 <description>
3948 Reserved for future use..
3949 </description>
3950 </field>
3951 <field id="reserved13">
3952 <ptrtype>
3953 <struct>jvmtiReservedCallback</struct>
3954 </ptrtype>
3955 <description>
3956 Reserved for future use..
3957 </description>
3958 </field>
3959 <field id="reserved14">
3960 <ptrtype>
3961 <struct>jvmtiReservedCallback</struct>
3962 </ptrtype>
3963 <description>
3964 Reserved for future use..
3965 </description>
3966 </field>
3967 <field id="reserved15">
3968 <ptrtype>
3969 <struct>jvmtiReservedCallback</struct>
3970 </ptrtype>
3971 <description>
3972 Reserved for future use..
3973 </description>
3974 </field>
3975 </typedef>
3976
3977
3978 <intro>
3979 <rationale>
3980 The heap dumping functionality (below) uses a callback
3981 for each object. While it would seem that a buffered approach
3982 would provide better throughput, tests do
3983 not show this to be the case--possibly due to locality of
3984 memory reference or array access overhead.
3985 </rationale>
3986
3987 <issue>
3988 Still under investigation as to if java.lang.ref references
3989 are reported as a different type of reference.
3990 </issue>
3991
3992 <issue>
3993 Should or can an indication of the cost or relative cost of
3994 these operations be included?
3995 </issue>
3996
3997 </intro>
3998
3999 <callback id="jvmtiHeapIterationCallback" since="1.1">
4000 <jint/>
4001 <synopsis>Heap Iteration Callback</synopsis>
4002 <description>
4003 Agent supplied callback function.
4004 Describes (but does not pass in) an object in the heap.
4005 <p/>
4006 This function should return a bit vector of the desired
4007 <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>.
4008 This will determine if the entire iteration should be aborted
4009 (the <code>JVMTI_VISIT_OBJECTS</code> flag is ignored).
4010 <p/>
4011 See the <internallink id="heapCallbacks">heap callback
4012 function restrictions</internallink>.
4013 </description>
4014 <parameters>
4015 <param id="class_tag">
4016 <jlong/>
4017 <description>
4018 The tag of the class of object (zero if the class is not tagged).
4019 If the object represents a runtime class,
4020 the <code>class_tag</code> is the tag
4021 associated with <code>java.lang.Class</code>
4022 (zero if <code>java.lang.Class</code> is not tagged).
4023 </description>
4024 </param>
4025 <param id="size">
4026 <jlong/>
4027 <description>
4028 Size of the object (in bytes). See <functionlink id="GetObjectSize"/>.
4029 </description>
4030 </param>
4031 <param id="tag_ptr">
4032 <outptr><jlong/></outptr>
4033 <description>
4034 The object tag value, or zero if the object is not tagged.
4035 To set the tag value to be associated with the object
4036 the agent sets the <code>jlong</code> pointed to by the parameter.
4037 </description>
4038 </param>
4039 <param id="length">
4040 <jint/>
4041 <description>
4042 If this object is an array, the length of the array. Otherwise negative one (-1).
4043 </description>
4044 </param>
4045 <param id="user_data">
4046 <outptr><void/></outptr>
4047 <description>
4048 The user supplied data that was passed into the iteration function.
4049 </description>
4050 </param>
4051 </parameters>
4052 </callback>
4053
4054 <callback id="jvmtiHeapReferenceCallback" since="1.1">
4055 <jint/>
4056 <synopsis>Heap Reference Callback</synopsis>
4057 <description>
4058 Agent supplied callback function.
4059 Describes a reference from an object or the VM (the referrer) to another object
4060 (the referree) or a heap root to a referree.
4061 <p/>
4062 This function should return a bit vector of the desired
4063 <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>.
4064 This will determine if the objects referenced by the referree
4065 should be visited or if the entire iteration should be aborted.
4066 <p/>
4067 See the <internallink id="heapCallbacks">heap callback
4068 function restrictions</internallink>.
4069 </description>
4070 <parameters>
4071 <param id="reference_kind">
4072 <enum>jvmtiHeapReferenceKind</enum>
4073 <description>
4074 The kind of reference.
4075 </description>
4076 </param>
4077 <param id="reference_info">
4078 <inptr>
4079 <struct>jvmtiHeapReferenceInfo</struct>
4080 </inptr>
4081 <description>
4082 Details about the reference.
4083 Set when the <datalink id="jvmtiHeapReferenceCallback.reference_kind">reference_kind</datalink> is
4084 <datalink id="JVMTI_HEAP_REFERENCE_FIELD"/>,
4085 <datalink id="JVMTI_HEAP_REFERENCE_STATIC_FIELD"/>,
4086 <datalink id="JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT"/>,
4087 <datalink id="JVMTI_HEAP_REFERENCE_CONSTANT_POOL"/>,
4088 <datalink id="JVMTI_HEAP_REFERENCE_STACK_LOCAL"/>,
4089 or <datalink id="JVMTI_HEAP_REFERENCE_JNI_LOCAL"/>.
4090 Otherwise <code>NULL</code>.
4091 </description>
4092 </param>
4093 <param id="class_tag">
4094 <jlong/>
4095 <description>
4096 The tag of the class of referree object (zero if the class is not tagged).
4097 If the referree object represents a runtime class,
4098 the <code>class_tag</code> is the tag
4099 associated with <code>java.lang.Class</code>
4100 (zero if <code>java.lang.Class</code> is not tagged).
4101 </description>
4102 </param>
4103 <param id="referrer_class_tag">
4104 <jlong/>
4105 <description>
4106 The tag of the class of the referrer object (zero if the class is not tagged
4107 or the referree is a heap root). If the referrer object represents a runtime
4108 class, the <code>referrer_class_tag</code> is the tag associated with
4109 the <code>java.lang.Class</code>
4110 (zero if <code>java.lang.Class</code> is not tagged).
4111 </description>
4112 </param>
4113 <param id="size">
4114 <jlong/>
4115 <description>
4116 Size of the referree object (in bytes).
4117 See <functionlink id="GetObjectSize"/>.
4118 </description>
4119 </param>
4120 <param id="tag_ptr">
4121 <outptr><jlong/></outptr>
4122 <description>
4123 Points to the referree object tag value, or zero if the object is not
4124 tagged.
4125 To set the tag value to be associated with the object
4126 the agent sets the <code>jlong</code> pointed to by the parameter.
4127 </description>
4128 </param>
4129 <param id="referrer_tag_ptr">
4130 <outptr><jlong/></outptr>
4131 <description>
4132 Points to the tag of the referrer object, or
4133 points to the zero if the referrer
4134 object is not tagged.
4135 <code>NULL</code> if the referrer in not an object (that is,
4136 this callback is reporting a heap root).
4137 To set the tag value to be associated with the referrer object
4138 the agent sets the <code>jlong</code> pointed to by the parameter.
4139 If this callback is reporting a reference from an object to itself,
4140 <code>referrer_tag_ptr == tag_ptr</code>.
4141 </description>
4142 </param>
4143 <param id="length">
4144 <jint/>
4145 <description>
4146 If this object is an array, the length of the array. Otherwise negative one (-1).
4147 </description>
4148 </param>
4149 <param id="user_data">
4150 <outptr><void/></outptr>
4151 <description>
4152 The user supplied data that was passed into the iteration function.
4153 </description>
4154 </param>
4155 </parameters>
4156 </callback>
4157
4158 <callback id="jvmtiPrimitiveFieldCallback" since="1.1">
4159 <jint/>
4160 <synopsis>Primitive Field Callback</synopsis>
4161 <description>
4162 Agent supplied callback function which
4163 describes a primitive field of an object (<i>the object</i>).
4164 A primitive field is a field whose type is a primitive type.
4165 This callback will describe a static field if the object is a class,
4166 and otherwise will describe an instance field.
4167 <p/>
4168 This function should return a bit vector of the desired
4169 <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>.
4170 This will determine if the entire iteration should be aborted
4171 (the <code>JVMTI_VISIT_OBJECTS</code> flag is ignored).
4172 <p/>
4173 See the <internallink id="heapCallbacks">heap callback
4174 function restrictions</internallink>.
4175 </description>
4176 <parameters>
4177 <param id="kind">
4178 <enum>jvmtiHeapReferenceKind</enum>
4179 <description>
4180 The kind of field -- instance or static (<datalink id="JVMTI_HEAP_REFERENCE_FIELD"/> or
4181 <datalink id="JVMTI_HEAP_REFERENCE_STATIC_FIELD"/>).
4182 </description>
4183 </param>
4184 <param id="info">
4185 <inptr>
4186 <struct>jvmtiHeapReferenceInfo</struct>
4187 </inptr>
4188 <description>
4189 Which field (the field index).
4190 </description>
4191 </param>
4192 <param id="object_class_tag">
4193 <jlong/>
4194 <description>
4195 The tag of the class of the object (zero if the class is not tagged).
4196 If the object represents a runtime class, the
4197 <code>object_class_tag</code> is the tag
4198 associated with <code>java.lang.Class</code>
4199 (zero if <code>java.lang.Class</code> is not tagged).
4200 </description>
4201 </param>
4202 <param id="object_tag_ptr">
4203 <outptr><jlong/></outptr>
4204 <description>
4205 Points to the tag of the object, or zero if the object is not
4206 tagged.
4207 To set the tag value to be associated with the object
4208 the agent sets the <code>jlong</code> pointed to by the parameter.
4209 </description>
4210 </param>
4211 <param id="value">
4212 <jvalue/>
4213 <description>
4214 The value of the field.
4215 </description>
4216 </param>
4217 <param id="value_type">
4218 <enum>jvmtiPrimitiveType</enum>
4219 <description>
4220 The type of the field.
4221 </description>
4222 </param>
4223 <param id="user_data">
4224 <outptr><void/></outptr>
4225 <description>
4226 The user supplied data that was passed into the iteration function.
4227 </description>
4228 </param>
4229 </parameters>
4230 </callback>
4231
4232 <callback id="jvmtiArrayPrimitiveValueCallback" since="1.1">
4233 <jint/>
4234 <synopsis>Array Primitive Value Callback</synopsis>
4235 <description>
4236 Agent supplied callback function.
4237 Describes the values in an array of a primitive type.
4238 <p/>
4239 This function should return a bit vector of the desired
4240 <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>.
4241 This will determine if the entire iteration should be aborted
4242 (the <code>JVMTI_VISIT_OBJECTS</code> flag is ignored).
4243 <p/>
4244 See the <internallink id="heapCallbacks">heap callback
4245 function restrictions</internallink>.
4246 </description>
4247 <parameters>
4248 <param id="class_tag">
4249 <jlong/>
4250 <description>
4251 The tag of the class of the array object (zero if the class is not tagged).
4252 </description>
4253 </param>
4254 <param id="size">
4255 <jlong/>
4256 <description>
4257 Size of the array (in bytes).
4258 See <functionlink id="GetObjectSize"/>.
4259 </description>
4260 </param>
4261 <param id="tag_ptr">
4262 <outptr><jlong/></outptr>
4263 <description>
4264 Points to the tag of the array object, or zero if the object is not
4265 tagged.
4266 To set the tag value to be associated with the object
4267 the agent sets the <code>jlong</code> pointed to by the parameter.
4268 </description>
4269 </param>
4270 <param id="element_count">
4271 <jint/>
4272 <description>
4273 The length of the primitive array.
4274 </description>
4275 </param>
4276 <param id="element_type">
4277 <enum>jvmtiPrimitiveType</enum>
4278 <description>
4279 The type of the elements of the array.
4280 </description>
4281 </param>
4282 <param id="elements">
4283 <vmbuf><void/></vmbuf>
4284 <description>
4285 The elements of the array in a packed array of <code>element_count</code>
4286 items of <code>element_type</code> size each.
4287 </description>
4288 </param>
4289 <param id="user_data">
4290 <outptr><void/></outptr>
4291 <description>
4292 The user supplied data that was passed into the iteration function.
4293 </description>
4294 </param>
4295 </parameters>
4296 </callback>
4297
4298 <callback id="jvmtiStringPrimitiveValueCallback" since="1.1">
4299 <jint/>
4300 <synopsis>String Primitive Value Callback</synopsis>
4301 <description>
4302 Agent supplied callback function.
4303 Describes the value of a java.lang.String.
4304 <p/>
4305 This function should return a bit vector of the desired
4306 <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>.
4307 This will determine if the entire iteration should be aborted
4308 (the <code>JVMTI_VISIT_OBJECTS</code> flag is ignored).
4309 <p/>
4310 See the <internallink id="heapCallbacks">heap callback
4311 function restrictions</internallink>.
4312 </description>
4313 <parameters>
4314 <param id="class_tag">
4315 <jlong/>
4316 <description>
4317 The tag of the class of the String class (zero if the class is not tagged).
4318 <issue>Is this needed?</issue>
4319 </description>
4320 </param>
4321 <param id="size">
4322 <jlong/>
4323 <description>
4324 Size of the string (in bytes).
4325 See <functionlink id="GetObjectSize"/>.
4326 </description>
4327 </param>
4328 <param id="tag_ptr">
4329 <outptr><jlong/></outptr>
4330 <description>
4331 Points to the tag of the String object, or zero if the object is not
4332 tagged.
4333 To set the tag value to be associated with the object
4334 the agent sets the <code>jlong</code> pointed to by the parameter.
4335 </description>
4336 </param>
4337 <param id="value">
4338 <vmbuf><jchar/></vmbuf>
4339 <description>
4340 The value of the String, encoded as a Unicode string.
4341 </description>
4342 </param>
4343 <param id="value_length">
4344 <jint/>
4345 <description>
4346 The length of the string.
4347 The length is equal to the number of 16-bit Unicode
4348 characters in the string.
4349 </description>
4350 </param>
4351 <param id="user_data">
4352 <outptr><void/></outptr>
4353 <description>
4354 The user supplied data that was passed into the iteration function.
4355 </description>
4356 </param>
4357 </parameters>
4358 </callback>
4359
4360
4361 <callback id="jvmtiReservedCallback" since="1.1">
4362 <jint/>
4363 <synopsis>reserved for future use Callback</synopsis>
4364 <description>
4365 Placeholder -- reserved for future use.
4366 </description>
4367 <parameters>
4368 </parameters>
4369 </callback>
4370
4371 <function id="FollowReferences" num="115" since="1.1">
4372 <synopsis>Follow References</synopsis>
4373 <description>
4374 This function initiates a traversal over the objects that are
4375 directly and indirectly reachable from the specified object or,
4376 if <code>initial_object</code> is not specified, all objects
4377 reachable from the heap roots.
4378 The heap root are the set of system classes,
4379 JNI globals, references from thread stacks, and other objects used as roots
4380 for the purposes of garbage collection.
4381 <p/>
4382 This function operates by traversing the reference graph.
4383 Let <i>A</i>, <i>B</i>, ... represent objects.
4384 When a reference from <i>A</i> to <i>B</i> is traversed,
4385 when a reference from a heap root to <i>B</i> is traversed,
4386 or when <i>B</i> is specified as the <paramlink id="initial_object"/>,
4387 then <i>B</i> is said to be <i>visited</i>.
4388 A reference from <i>A</i> to <i>B</i> is not traversed until <i>A</i>
4389 is visited.
4390 References are reported in the same order that the references are traversed.
4391 Object references are reported by invoking the agent supplied
4392 callback function <functionlink id="jvmtiHeapReferenceCallback"/>.
4393 In a reference from <i>A</i> to <i>B</i>, <i>A</i> is known
4394 as the <i>referrer</i> and <i>B</i> as the <i>referree</i>.
4395 The callback is invoked exactly once for each reference from a referrer;
4396 this is true even if there are reference cycles or multiple paths to
4397 the referrer.
4398 There may be more than one reference between a referrer and a referree,
4399 each reference is reported.
4400 These references may be distinguished by examining the
4401 <datalink
4402 id="jvmtiHeapReferenceCallback.reference_kind"><code>reference_kind</code></datalink>
4403 and
4404 <datalink
4405 id="jvmtiHeapReferenceCallback.reference_info"><code>reference_info</code></datalink>
4406 parameters of the <functionlink id="jvmtiHeapReferenceCallback"/> callback.
4407 <p/>
4408 This function reports a Java programming language view of object references,
4409 not a virtual machine implementation view. The following object references
4410 are reported when they are non-null:
4411 <ul>
4412 <li>Instance objects report references to each non-primitive instance fields
4413 (including inherited fields).</li>
4414 <li>Instance objects report a reference to the object type (class).</li>
4415 <li>Classes report a reference to the superclass and directly
4416 implemented/extended interfaces.</li>
4417 <li>Classes report a reference to the class loader, protection domain,
4418 signers, and resolved entries in the constant pool.</li>
4419 <li>Classes report a reference to each directly declared non-primitive
4420 static field.</li>
4421 <li>Arrays report a reference to the array type (class) and each
4422 array element.</li>
4423 <li>Primitive arrays report a reference to the array type.</li>
4424 </ul>
4425 <p/>
4426 This function can also be used to examine primitive (non-object) values.
4427 The primitive value of an array or String
4428 is reported after the object has been visited;
4429 it is reported by invoking the agent supplied callback function
4430 <functionlink id="jvmtiArrayPrimitiveValueCallback"/> or
4431 <functionlink id="jvmtiStringPrimitiveValueCallback"/>.
4432 A primitive field
4433 is reported after the object with that field is visited;
4434 it is reported by invoking the agent supplied callback function
4435 <functionlink id="jvmtiPrimitiveFieldCallback"/>.
4436 <p/>
4437 Whether a callback is provided or is <code>NULL</code> only determines
4438 whether the callback will be invoked, it does not influence
4439 which objects are visited nor does it influence whether other callbacks
4440 will be invoked.
4441 However, the
4442 <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>
4443 returned by <functionlink id="jvmtiHeapReferenceCallback"/>
4444 do determine if the objects referenced by the
4445 current object as visited.
4446 The <datalink id="jvmtiHeapFilter">heap filter flags</datalink>
4447 and <paramlink id="klass"/> provided as parameters to this function
4448 do not control which objects are visited but they do control which
4449 objects and primitive values are reported by the callbacks.
4450 For example, if the only callback that was set is
4451 <fieldlink id="array_primitive_value_callback" struct="jvmtiHeapCallbacks"/> and <code>klass</code>
4452 is set to the array of bytes class, then only arrays of byte will be
4453 reported.
4454 The table below summarizes this:
4455 <p/>
4456 <table>
4457 <tr>
4458 <th/>
4459 <th>
4460 Controls objects visited
4461 </th>
4462 <th>
4463 Controls objects reported
4464 </th>
4465 <th>
4466 Controls primitives reported
4467 </th>
4468 </tr>
4469 <tr>
4470 <th align="left">
4471 the
4472 <datalink id="jvmtiHeapVisitControl">Heap Visit Control Flags</datalink>
4473 returned by <functionlink id="jvmtiHeapReferenceCallback"/>
4474 </th>
4475 <td>
4476 <b>Yes</b>
4477 </td>
4478 <td>
4479 <b>Yes</b>, since visits are controlled
4480 </td>
4481 <td>
4482 <b>Yes</b>, since visits are controlled
4483 </td>
4484 </tr>
4485 <tr>
4486 <th align="left">
4487 <fieldlink id="array_primitive_value_callback" struct="jvmtiHeapCallbacks"/>
4488 in <paramlink id="callbacks"/> set
4489 </th>
4490 <td>
4491 No
4492 </td>
4493 <td>
4494 <b>Yes</b>
4495 </td>
4496 <td>
4497 No
4498 </td>
4499 </tr>
4500 <tr>
4501 <th align="left">
4502 <paramlink id="heap_filter"/>
4503 </th>
4504 <td>
4505 No
4506 </td>
4507 <td>
4508 <b>Yes</b>
4509 </td>
4510 <td>
4511 <b>Yes</b>
4512 </td>
4513 </tr>
4514 <tr>
4515 <th align="left">
4516 <paramlink id="klass"/>
4517 </th>
4518 <td>
4519 No
4520 </td>
4521 <td>
4522 <b>Yes</b>
4523 </td>
4524 <td>
4525 <b>Yes</b>
4526 </td>
4527 </tr>
4528 </table>
4529 <p/>
4530 During the execution of this function the state of the heap
4531 does not change: no objects are allocated, no objects are
4532 garbage collected, and the state of objects (including
4533 held values) does not change.
4534 As a result, threads executing Java
4535 programming language code, threads attempting to resume the
4536 execution of Java programming language code, and threads
4537 attempting to execute JNI functions are typically stalled.
4538 </description>
4539 <origin>new</origin>
4540 <capabilities>
4541 <required id="can_tag_objects"></required>
4542 </capabilities>
4543 <parameters>
4544 <param id="heap_filter">
4545 <jint/>
4546 <description>
4547 This bit vector of
4548 <datalink id="jvmtiHeapFilter">heap filter flags</datalink>.
4549 restricts the objects for which the callback function is called.
4550 This applies to both the object and primitive callbacks.
4551 </description>
4552 </param>
4553 <param id="klass">
4554 <ptrtype>
4555 <jclass/>
4556 <nullok>callbacks are not limited to instances of a particular
4557 class</nullok>
4558 </ptrtype>
4559 <description>
4560 Callbacks are only reported when the object is an instance of
4561 this class.
4562 Objects which are instances of a subclass of <code>klass</code>
4563 are not reported.
4564 If <code>klass</code> is an interface, no objects are reported.
4565 This applies to both the object and primitive callbacks.
4566 </description>
4567 </param>
4568 <param id="initial_object">
4569 <ptrtype>
4570 <jobject/>
4571 <nullok>references are followed from the heap roots</nullok>
4572 </ptrtype>
4573 <description>
4574 The object to follow
4575 </description>
4576 </param>
4577 <param id="callbacks">
4578 <inptr>
4579 <struct>jvmtiHeapCallbacks</struct>
4580 </inptr>
4581 <description>
4582 Structure defining the set of callback functions.
4583 </description>
4584 </param>
4585 <param id="user_data">
4586 <inbuf>
4587 <void/>
4588 <nullok><code>NULL</code> is passed as the user supplied data</nullok>
4589 </inbuf>
4590 <description>
4591 User supplied data to be passed to the callback.
4592 </description>
4593 </param>
4594 </parameters>
4595 <errors>
4596 <error id="JVMTI_ERROR_INVALID_CLASS">
4597 <paramlink id="klass"/> is not a valid class.
4598 </error>
4599 <error id="JVMTI_ERROR_INVALID_OBJECT">
4600 <paramlink id="initial_object"/> is not a valid object.
4601 </error>
4602 </errors>
4603 </function>
4604
4605
4606 <function id="IterateThroughHeap" num="116" since="1.1">
4607 <synopsis>Iterate Through Heap</synopsis>
4608 <description>
4609 Initiate an iteration over all objects in the heap.
4610 This includes both reachable and
4611 unreachable objects. Objects are visited in no particular order.
4612 <p/>
4613 Heap objects are reported by invoking the agent supplied
4614 callback function <functionlink id="jvmtiHeapIterationCallback"/>.
4615 References between objects are not reported.
4616 If only reachable objects are desired, or if object reference information
4617 is needed, use <functionlink id="FollowReferences"/>.
4618 <p/>
4619 This function can also be used to examine primitive (non-object) values.
4620 The primitive value of an array or String
4621 is reported after the object has been visited;
4622 it is reported by invoking the agent supplied callback function
4623 <functionlink id="jvmtiArrayPrimitiveValueCallback"/> or
4624 <functionlink id="jvmtiStringPrimitiveValueCallback"/>.
4625 A primitive field
4626 is reported after the object with that field is visited;
4627 it is reported by invoking the agent supplied
4628 callback function
4629 <functionlink id="jvmtiPrimitiveFieldCallback"/>.
4630 <p/>
4631 Unless the iteration is aborted by the
4632 <datalink id="jvmtiHeapVisitControl">Heap Visit Control Flags</datalink>
4633 returned by a callback, all objects in the heap are visited.
4634 Whether a callback is provided or is <code>NULL</code> only determines
4635 whether the callback will be invoked, it does not influence
4636 which objects are visited nor does it influence whether other callbacks
4637 will be invoked.
4638 The <datalink id="jvmtiHeapFilter">heap filter flags</datalink>
4639 and <paramlink id="klass"/> provided as parameters to this function
4640 do not control which objects are visited but they do control which
4641 objects and primitive values are reported by the callbacks.
4642 For example, if the only callback that was set is
4643 <fieldlink id="array_primitive_value_callback" struct="jvmtiHeapCallbacks"/> and <code>klass</code>
4644 is set to the array of bytes class, then only arrays of byte will be
4645 reported. The table below summarizes this (contrast this with
4646 <functionlink id="FollowReferences"/>):
4647 <p/>
4648 <table>
4649 <tr>
4650 <th/>
4651 <th>
4652 Controls objects visited
4653 </th>
4654 <th>
4655 Controls objects reported
4656 </th>
4657 <th>
4658 Controls primitives reported
4659 </th>
4660 </tr>
4661 <tr>
4662 <th align="left">
4663 the
4664 <datalink id="jvmtiHeapVisitControl">Heap Visit Control Flags</datalink>
4665 returned by <functionlink id="jvmtiHeapIterationCallback"/>
4666 </th>
4667 <td>
4668 No<br/>(unless they abort the iteration)
4669 </td>
4670 <td>
4671 No<br/>(unless they abort the iteration)
4672 </td>
4673 <td>
4674 No<br/>(unless they abort the iteration)
4675 </td>
4676 </tr>
4677 <tr>
4678 <th align="left">
4679 <fieldlink id="array_primitive_value_callback" struct="jvmtiHeapCallbacks"/>
4680 in <paramlink id="callbacks"/> set
4681 </th>
4682 <td>
4683 No
4684 </td>
4685 <td>
4686 <b>Yes</b>
4687 </td>
4688 <td>
4689 No
4690 </td>
4691 </tr>
4692 <tr>
4693 <th align="left">
4694 <paramlink id="heap_filter"/>
4695 </th>
4696 <td>
4697 No
4698 </td>
4699 <td>
4700 <b>Yes</b>
4701 </td>
4702 <td>
4703 <b>Yes</b>
4704 </td>
4705 </tr>
4706 <tr>
4707 <th align="left">
4708 <paramlink id="klass"/>
4709 </th>
4710 <td>
4711 No
4712 </td>
4713 <td>
4714 <b>Yes</b>
4715 </td>
4716 <td>
4717 <b>Yes</b>
4718 </td>
4719 </tr>
4720 </table>
4721 <p/>
4722 During the execution of this function the state of the heap
4723 does not change: no objects are allocated, no objects are
4724 garbage collected, and the state of objects (including
4725 held values) does not change.
4726 As a result, threads executing Java
4727 programming language code, threads attempting to resume the
4728 execution of Java programming language code, and threads
4729 attempting to execute JNI functions are typically stalled.
4730 </description>
4731 <origin>new</origin>
4732 <capabilities>
4733 <required id="can_tag_objects"></required>
4734 </capabilities>
4735 <parameters>
4736 <param id="heap_filter">
4737 <jint/>
4738 <description>
4739 This bit vector of
4740 <datalink id="jvmtiHeapFilter">heap filter flags</datalink>.
4741 restricts the objects for which the callback function is called.
4742 This applies to both the object and primitive callbacks.
4743 </description>
4744 </param>
4745 <param id="klass">
4746 <ptrtype>
4747 <jclass/>
4748 <nullok>callbacks are not limited to instances of a particular class</nullok>
4749 </ptrtype>
4750 <description>
4751 Callbacks are only reported when the object is an instance of
4752 this class.
4753 Objects which are instances of a subclass of <code>klass</code>
4754 are not reported.
4755 If <code>klass</code> is an interface, no objects are reported.
4756 This applies to both the object and primitive callbacks.
4757 </description>
4758 </param>
4759 <param id="callbacks">
4760 <inptr>
4761 <struct>jvmtiHeapCallbacks</struct>
4762 </inptr>
4763 <description>
4764 Structure defining the set callback functions.
4765 </description>
4766 </param>
4767 <param id="user_data">
4768 <inbuf>
4769 <void/>
4770 <nullok><code>NULL</code> is passed as the user supplied data</nullok>
4771 </inbuf>
4772 <description>
4773 User supplied data to be passed to the callback.
4774 </description>
4775 </param>
4776 </parameters>
4777 <errors>
4778 <error id="JVMTI_ERROR_INVALID_CLASS">
4779 <paramlink id="klass"/> is not a valid class.
4780 </error>
4781 </errors>
4782 </function>
4783
4784 <function id="GetTag" phase="start" num="106">
4785 <synopsis>Get Tag</synopsis>
4786 <description>
4787 Retrieve the tag associated with an object.
4788 The tag is a long value typically used to store a
4789 unique identifier or pointer to object information.
4790 The tag is set with
4791 <functionlink id="SetTag"></functionlink>.
4792 Objects for which no tags have been set return a
4793 tag value of zero.
4794 </description>
4795 <origin>new</origin>
4796 <capabilities>
4797 <required id="can_tag_objects"></required>
4798 </capabilities>
4799 <parameters>
4800 <param id="object">
4801 <jobject/>
4802 <description>
4803 The object whose tag is to be retrieved.
4804 </description>
4805 </param>
4806 <param id="tag_ptr">
4807 <outptr><jlong/></outptr>
4808 <description>
4809 On return, the referenced long is set to the value
4810 of the tag.
4811 </description>
4812 </param>
4813 </parameters>
4814 <errors>
4815 </errors>
4816 </function>
4817
4818 <function id="SetTag" phase="start" num="107">
4819 <synopsis>Set Tag</synopsis>
4820 <description>
4821 Set the tag associated with an object.
4822 The tag is a long value typically used to store a
4823 unique identifier or pointer to object information.
4824 The tag is visible with
4825 <functionlink id="GetTag"></functionlink>.
4826 </description>
4827 <origin>new</origin>
4828 <capabilities>
4829 <required id="can_tag_objects"></required>
4830 </capabilities>
4831 <parameters>
4832 <param id="object">
4833 <jobject/>
4834 <description>
4835 The object whose tag is to be set.
4836 </description>
4837 </param>
4838 <param id="tag">
4839 <jlong/>
4840 <description>
4841 The new value of the tag.
4842 </description>
4843 </param>
4844 </parameters>
4845 <errors>
4846 </errors>
4847 </function>
4848
4849 <function id="GetObjectsWithTags" num="114">
4850 <synopsis>Get Objects With Tags</synopsis>
4851 <description>
4852 Return objects in the heap with the specified tags.
4853 The format is parallel arrays of objects and tags.
4854 </description>
4855 <origin>new</origin>
4856 <capabilities>
4857 <required id="can_tag_objects"></required>
4858 </capabilities>
4859 <parameters>
4860 <param id="tag_count">
4861 <jint min="0"/>
4862 <description>
4863 Number of tags to scan for.
4864 </description>
4865 </param>
4866 <param id="tags">
4867 <inbuf incount="tag_count">
4868 <jlong/>
4869 </inbuf>
4870 <description>
4871 Scan for objects with these tags.
4872 Zero is not permitted in this array.
4873 </description>
4874 </param>
4875 <param id="count_ptr">
4876 <outptr>
4877 <jint/>
4878 </outptr>
4879 <description>
4880 Return the number of objects with any of the tags
4881 in <paramlink id="tags"/>.
4882 </description>
4883 </param>
4884 <param id="object_result_ptr">
4885 <allocbuf outcount="count_ptr">
4886 <jobject/>
4887 <nullok>this information is not returned</nullok>
4888 </allocbuf>
4889 <description>
4890 Returns the array of objects with any of the tags
4891 in <paramlink id="tags"/>.
4892 </description>
4893 </param>
4894 <param id="tag_result_ptr">
4895 <allocbuf outcount="count_ptr">
4896 <jlong/>
4897 <nullok>this information is not returned</nullok>
4898 </allocbuf>
4899 <description>
4900 For each object in <paramlink id="object_result_ptr"/>,
4901 return the tag at the corresponding index.
4902 </description>
4903 </param>
4904 </parameters>
4905 <errors>
4906 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
4907 Zero is present in <paramlink id="tags"></paramlink>.
4908 </error>
4909 </errors>
4910 </function>
4911
4912 <function id="ForceGarbageCollection" num="108">
4913 <synopsis>Force Garbage Collection</synopsis>
4914 <description>
4915 Force the VM to perform a garbage collection.
4916 The garbage collection is as complete as possible.
4917 This function does not cause finalizers to be run.
4918 This function does not return until the garbage collection
4919 is finished.
4920 <p/>
4921 Although garbage collection is as complete
4922 as possible there is no guarantee that all
4923 <eventlink id="ObjectFree"/>
4924 events will have been
4925 sent by the time that this function
4926 returns. In particular, an object may be
4927 prevented from being freed because it
4928 is awaiting finalization.
4929 </description>
4930 <origin>new</origin>
4931 <capabilities>
4932 </capabilities>
4933 <parameters>
4934 </parameters>
4935 <errors>
4936 </errors>
4937 </function>
4938
4939
4940 </category>
4941
4942 <category id="Heap_1_0" label="Heap (1.0)">
4943 <intro>
4944 <b>
4945 These functions and data types were introduced in the original
4946 <jvmti/> version 1.0 and have been superseded by more
4947 </b>
4948 <internallink id="Heap"><b>powerful and flexible versions</b></internallink>
4949 <b>
4950 which:
4951 </b>
4952 <ul>
4953 <li>
4954 <b>
4955 Allow access to primitive values (the value of Strings, arrays,
4956 and primitive fields)
4957 </b>
4958 </li>
4959 <li>
4960 <b>
4961 Allow the tag of the referrer to be set, thus enabling more
4962 efficient localized reference graph building
4963 </b>
4964 </li>
4965 <li>
4966 <b>
4967 Provide more extensive filtering abilities
4968 </b>
4969 </li>
4970 <li>
4971 <b>
4972 Are extensible, allowing their abilities to grow in future versions of <jvmti/>
4973 </b>
4974 </li>
4975 </ul>
4976 <p/>
4977 <b>Please use the </b>
4978 <internallink id="Heap"><b>current Heap functions</b></internallink>.
4979 <p/>
4980 <constants id="jvmtiHeapObjectFilter" label="Heap Object Filter Enumeration" kind="enum">
4981 <constant id="JVMTI_HEAP_OBJECT_TAGGED" num="1">
4982 Tagged objects only.
4983 </constant>
4984 <constant id="JVMTI_HEAP_OBJECT_UNTAGGED" num="2">
4985 Untagged objects only.
4986 </constant>
4987 <constant id="JVMTI_HEAP_OBJECT_EITHER" num="3">
4988 Either tagged or untagged objects.
4989 </constant>
4990 </constants>
4991
4992 <constants id="jvmtiHeapRootKind" label="Heap Root Kind Enumeration" kind="enum">
4993 <constant id="JVMTI_HEAP_ROOT_JNI_GLOBAL" num="1">
4994 JNI global reference.
4995 </constant>
4996 <constant id="JVMTI_HEAP_ROOT_SYSTEM_CLASS" num="2">
4997 System class.
4998 </constant>
4999 <constant id="JVMTI_HEAP_ROOT_MONITOR" num="3">
5000 Monitor.
5001 </constant>
5002 <constant id="JVMTI_HEAP_ROOT_STACK_LOCAL" num="4">
5003 Stack local.
5004 </constant>
5005 <constant id="JVMTI_HEAP_ROOT_JNI_LOCAL" num="5">
5006 JNI local reference.
5007 </constant>
5008 <constant id="JVMTI_HEAP_ROOT_THREAD" num="6">
5009 Thread.
5010 </constant>
5011 <constant id="JVMTI_HEAP_ROOT_OTHER" num="7">
5012 Other.
5013 </constant>
5014 </constants>
5015
5016 <constants id="jvmtiObjectReferenceKind" label="Object Reference Enumeration" kind="enum">
5017 <constant id="JVMTI_REFERENCE_CLASS" num="1">
5018 Reference from an object to its class.
5019 </constant>
5020 <constant id="JVMTI_REFERENCE_FIELD" num="2">
5021 Reference from an object to the value of one of its instance fields.
5022 For references of this kind the <code>referrer_index</code>
5023 parameter to the <internallink id="jvmtiObjectReferenceCallback">
5024 jvmtiObjectReferenceCallback</internallink> is the index of the
5025 the instance field. The index is based on the order of all the
5026 object's fields. This includes all fields of the directly declared
5027 static and instance fields in the class, and includes all fields (both
5028 public and private) fields declared in superclasses and superinterfaces.
5029 The index is thus calculated by summing the index of the field in the directly
5030 declared class (see <functionlink id="GetClassFields"/>), with the total
5031 number of fields (both public and private) declared in all superclasses
5032 and superinterfaces. The index starts at zero.
5033 </constant>
5034 <constant id="JVMTI_REFERENCE_ARRAY_ELEMENT" num="3">
5035 Reference from an array to one of its elements.
5036 For references of this kind the <code>referrer_index</code>
5037 parameter to the <internallink id="jvmtiObjectReferenceCallback">
5038 jvmtiObjectReferenceCallback</internallink> is the array index.
5039 </constant>
5040 <constant id="JVMTI_REFERENCE_CLASS_LOADER" num="4">
5041 Reference from a class to its class loader.
5042 </constant>
5043 <constant id="JVMTI_REFERENCE_SIGNERS" num="5">
5044 Reference from a class to its signers array.
5045 </constant>
5046 <constant id="JVMTI_REFERENCE_PROTECTION_DOMAIN" num="6">
5047 Reference from a class to its protection domain.
5048 </constant>
5049 <constant id="JVMTI_REFERENCE_INTERFACE" num="7">
5050 Reference from a class to one of its interfaces.
5051 </constant>
5052 <constant id="JVMTI_REFERENCE_STATIC_FIELD" num="8">
5053 Reference from a class to the value of one of its static fields.
5054 For references of this kind the <code>referrer_index</code>
5055 parameter to the <internallink id="jvmtiObjectReferenceCallback">
5056 jvmtiObjectReferenceCallback</internallink> is the index of the
5057 the static field. The index is based on the order of all the
5058 object's fields. This includes all fields of the directly declared
5059 static and instance fields in the class, and includes all fields (both
5060 public and private) fields declared in superclasses and superinterfaces.
5061 The index is thus calculated by summing the index of the field in the directly
5062 declared class (see <functionlink id="GetClassFields"/>), with the total
5063 number of fields (both public and private) declared in all superclasses
5064 and superinterfaces. The index starts at zero.
5065 Note: this definition differs from that in the <jvmti/> 1.0 Specification.
5066 <rationale>No known implementations used the 1.0 definition.</rationale>
5067 </constant>
5068 <constant id="JVMTI_REFERENCE_CONSTANT_POOL" num="9">
5069 Reference from a class to a resolved entry in the constant pool.
5070 For references of this kind the <code>referrer_index</code>
5071 parameter to the <internallink id="jvmtiObjectReferenceCallback">
5072 jvmtiObjectReferenceCallback</internallink> is the index into
5073 constant pool table of the class, starting at 1. See
5074 <vmspec chapter="4.4"/>.
5075 </constant>
5076 </constants>
5077
5078 <constants id="jvmtiIterationControl" label="Iteration Control Enumeration" kind="enum">
5079 <constant id="JVMTI_ITERATION_CONTINUE" num="1">
5080 Continue the iteration.
5081 If this is a reference iteration, follow the references of this object.
5082 </constant>
5083 <constant id="JVMTI_ITERATION_IGNORE" num="2">
5084 Continue the iteration.
5085 If this is a reference iteration, ignore the references of this object.
5086 </constant>
5087 <constant id="JVMTI_ITERATION_ABORT" num="0">
5088 Abort the iteration.
5089 </constant>
5090 </constants>
5091 </intro>
5092
5093 <callback id="jvmtiHeapObjectCallback">
5094 <enum>jvmtiIterationControl</enum>
5095 <synopsis>Heap Object Callback</synopsis>
5096 <description>
5097 Agent supplied callback function.
5098 Describes (but does not pass in) an object in the heap.
5099 <p/>
5100 Return value should be <code>JVMTI_ITERATION_CONTINUE</code> to continue iteration,
5101 or <code>JVMTI_ITERATION_ABORT</code> to stop iteration.
5102 <p/>
5103 See the <internallink id="heapCallbacks">heap callback
5104 function restrictions</internallink>.
5105 </description>
5106 <parameters>
5107 <param id="class_tag">
5108 <jlong/>
5109 <description>
5110 The tag of the class of object (zero if the class is not tagged).
5111 If the object represents a runtime class,
5112 the <code>class_tag</code> is the tag
5113 associated with <code>java.lang.Class</code>
5114 (zero if <code>java.lang.Class</code> is not tagged).
5115 </description>
5116 </param>
5117 <param id="size">
5118 <jlong/>
5119 <description>
5120 Size of the object (in bytes). See <functionlink id="GetObjectSize"/>.
5121 </description>
5122 </param>
5123 <param id="tag_ptr">
5124 <outptr><jlong/></outptr>
5125 <description>
5126 The object tag value, or zero if the object is not tagged.
5127 To set the tag value to be associated with the object
5128 the agent sets the <code>jlong</code> pointed to by the parameter.
5129 </description>
5130 </param>
5131 <param id="user_data">
5132 <outptr><void/></outptr>
5133 <description>
5134 The user supplied data that was passed into the iteration function.
5135 </description>
5136 </param>
5137 </parameters>
5138 </callback>
5139
5140 <callback id="jvmtiHeapRootCallback">
5141 <enum>jvmtiIterationControl</enum>
5142 <synopsis>Heap Root Object Callback</synopsis>
5143 <description>
5144 Agent supplied callback function.
5145 Describes (but does not pass in) an object that is a root for the purposes
5146 of garbage collection.
5147 <p/>
5148 Return value should be <code>JVMTI_ITERATION_CONTINUE</code> to continue iteration,
5149 <code>JVMTI_ITERATION_IGNORE</code> to continue iteration without pursuing
5150 references from referree object or <code>JVMTI_ITERATION_ABORT</code> to stop iteration.
5151 <p/>
5152 See the <internallink id="heapCallbacks">heap callback
5153 function restrictions</internallink>.
5154 </description>
5155 <parameters>
5156 <param id="root_kind">
5157 <enum>jvmtiHeapRootKind</enum>
5158 <description>
5159 The kind of heap root.
5160 </description>
5161 </param>
5162 <param id="class_tag">
5163 <jlong/>
5164 <description>
5165 The tag of the class of object (zero if the class is not tagged).
5166 If the object represents a runtime class, the <code>class_tag</code> is the tag
5167 associated with <code>java.lang.Class</code>
5168 (zero if <code>java.lang.Class</code> is not tagged).
5169 </description>
5170 </param>
5171 <param id="size">
5172 <jlong/>
5173 <description>
5174 Size of the object (in bytes). See <functionlink id="GetObjectSize"/>.
5175 </description>
5176 </param>
5177 <param id="tag_ptr">
5178 <outptr><jlong/></outptr>
5179 <description>
5180 The object tag value, or zero if the object is not tagged.
5181 To set the tag value to be associated with the object
5182 the agent sets the <code>jlong</code> pointed to by the parameter.
5183 </description>
5184 </param>
5185 <param id="user_data">
5186 <outptr><void/></outptr>
5187 <description>
5188 The user supplied data that was passed into the iteration function.
5189 </description>
5190 </param>
5191 </parameters>
5192 </callback>
5193
5194 <callback id="jvmtiStackReferenceCallback">
5195 <enum>jvmtiIterationControl</enum>
5196 <synopsis>Stack Reference Object Callback</synopsis>
5197 <description>
5198 Agent supplied callback function.
5199 Describes (but does not pass in) an object on the stack that is a root for
5200 the purposes of garbage collection.
5201 <p/>
5202 Return value should be <code>JVMTI_ITERATION_CONTINUE</code> to continue iteration,
5203 <code>JVMTI_ITERATION_IGNORE</code> to continue iteration without pursuing
5204 references from referree object or <code>JVMTI_ITERATION_ABORT</code> to stop iteration.
5205 <p/>
5206 See the <internallink id="heapCallbacks">heap callback
5207 function restrictions</internallink>.
5208 </description>
5209 <parameters>
5210 <param id="root_kind">
5211 <enum>jvmtiHeapRootKind</enum>
5212 <description>
5213 The kind of root (either <code>JVMTI_HEAP_ROOT_STACK_LOCAL</code> or
5214 <code>JVMTI_HEAP_ROOT_JNI_LOCAL</code>).
5215 </description>
5216 </param>
5217 <param id="class_tag">
5218 <jlong/>
5219 <description>
5220 The tag of the class of object (zero if the class is not tagged).
5221 If the object represents a runtime class, the <code>class_tag</code> is the tag
5222 associated with <code>java.lang.Class</code>
5223 (zero if <code>java.lang.Class</code> is not tagged).
5224 </description>
5225 </param>
5226 <param id="size">
5227 <jlong/>
5228 <description>
5229 Size of the object (in bytes). See <functionlink id="GetObjectSize"/>.
5230 </description>
5231 </param>
5232 <param id="tag_ptr">
5233 <outptr><jlong/></outptr>
5234 <description>
5235 The object tag value, or zero if the object is not tagged.
5236 To set the tag value to be associated with the object
5237 the agent sets the <code>jlong</code> pointed to by the parameter.
5238 </description>
5239 </param>
5240 <param id="thread_tag">
5241 <jlong/>
5242 <description>
5243 The tag of the thread corresponding to this stack, zero if not tagged.
5244 </description>
5245 </param>
5246 <param id="depth">
5247 <jint/>
5248 <description>
5249 The depth of the frame.
5250 </description>
5251 </param>
5252 <param id="method">
5253 <jmethodID/>
5254 <description>
5255 The method executing in this frame.
5256 </description>
5257 </param>
5258 <param id="slot">
5259 <jint/>
5260 <description>
5261 The slot number.
5262 </description>
5263 </param>
5264 <param id="user_data">
5265 <outptr><void/></outptr>
5266 <description>
5267 The user supplied data that was passed into the iteration function.
5268 </description>
5269 </param>
5270 </parameters>
5271 </callback>
5272
5273 <callback id="jvmtiObjectReferenceCallback">
5274 <enum>jvmtiIterationControl</enum>
5275 <synopsis>Object Reference Callback</synopsis>
5276 <description>
5277 Agent supplied callback function.
5278 Describes a reference from an object (the referrer) to another object
5279 (the referree).
5280 <p/>
5281 Return value should be <code>JVMTI_ITERATION_CONTINUE</code> to continue iteration,
5282 <code>JVMTI_ITERATION_IGNORE</code> to continue iteration without pursuing
5283 references from referree object or <code>JVMTI_ITERATION_ABORT</code> to stop iteration.
5284 <p/>
5285 See the <internallink id="heapCallbacks">heap callback
5286 function restrictions</internallink>.
5287 </description>
5288 <parameters>
5289 <param id="reference_kind">
5290 <enum>jvmtiObjectReferenceKind</enum>
5291 <description>
5292 The type of reference.
5293 </description>
5294 </param>
5295 <param id="class_tag">
5296 <jlong/>
5297 <description>
5298 The tag of the class of referree object (zero if the class is not tagged).
5299 If the referree object represents a runtime class,
5300 the <code>class_tag</code> is the tag
5301 associated with <code>java.lang.Class</code>
5302 (zero if <code>java.lang.Class</code> is not tagged).
5303 </description>
5304 </param>
5305 <param id="size">
5306 <jlong/>
5307 <description>
5308 Size of the referree object (in bytes).
5309 See <functionlink id="GetObjectSize"/>.
5310 </description>
5311 </param>
5312 <param id="tag_ptr">
5313 <outptr><jlong/></outptr>
5314 <description>
5315 The referree object tag value, or zero if the object is not
5316 tagged.
5317 To set the tag value to be associated with the object
5318 the agent sets the <code>jlong</code> pointed to by the parameter.
5319 </description>
5320 </param>
5321 <param id="referrer_tag">
5322 <jlong/>
5323 <description>
5324 The tag of the referrer object, or zero if the referrer
5325 object is not tagged.
5326 </description>
5327 </param>
5328 <param id="referrer_index">
5329 <jint/>
5330 <description>
5331 For references of type <code>JVMTI_REFERENCE_FIELD</code> or
5332 <code>JVMTI_REFERENCE_STATIC_FIELD</code> the index
5333 of the field in the referrer object. The index is based on the
5334 order of all the object's fields - see <internallink
5335 id="JVMTI_REFERENCE_FIELD">JVMTI_REFERENCE_FIELD</internallink>
5336 or <internallink
5337 id="JVMTI_REFERENCE_STATIC_FIELD">JVMTI_REFERENCE_STATIC_FIELD
5338 </internallink> for further description.
5339 <p/>
5340 For references of type <code>JVMTI_REFERENCE_ARRAY_ELEMENT</code>
5341 the array index - see <internallink id="JVMTI_REFERENCE_ARRAY_ELEMENT">
5342 JVMTI_REFERENCE_ARRAY_ELEMENT</internallink> for further description.
5343 <p/>
5344 For references of type <code>JVMTI_REFERENCE_CONSTANT_POOL</code>
5345 the index into the constant pool of the class - see
5346 <internallink id="JVMTI_REFERENCE_CONSTANT_POOL">
5347 JVMTI_REFERENCE_CONSTANT_POOL</internallink> for further
5348 description.
5349 <p/>
5350 For references of other kinds the <code>referrer_index</code> is
5351 <code>-1</code>.
5352 </description>
5353 </param>
5354 <param id="user_data">
5355 <outptr><void/></outptr>
5356 <description>
5357 The user supplied data that was passed into the iteration function.
5358 </description>
5359 </param>
5360 </parameters>
5361 </callback>
5362
5363 <function id="IterateOverObjectsReachableFromObject" num="109">
5364 <synopsis>Iterate Over Objects Reachable From Object</synopsis>
5365 <description>
5366 This function iterates over all objects that are directly
5367 and indirectly reachable from the specified object.
5368 For each object <i>A</i> (known
5369 as the referrer) with a reference to object <i>B</i> the specified
5370 callback function is called to describe the object reference.
5371 The callback is called exactly once for each reference from a referrer;
5372 this is true even if there are reference cycles or multiple paths to
5373 the referrer.
5374 There may be more than one reference between a referrer and a referree,
5375 These may be distinguished by the
5376 <datalink id="jvmtiObjectReferenceCallback.reference_kind"></datalink> and
5377 <datalink id="jvmtiObjectReferenceCallback.referrer_index"></datalink>.
5378 The callback for an object will always occur after the callback for
5379 its referrer.
5380 <p/>
5381 See <functionlink id="FollowReferences"/> for the object
5382 references which are reported.
5383 <p/>
5384 During the execution of this function the state of the heap
5385 does not change: no objects are allocated, no objects are
5386 garbage collected, and the state of objects (including
5387 held values) does not change.
5388 As a result, threads executing Java
5389 programming language code, threads attempting to resume the
5390 execution of Java programming language code, and threads
5391 attempting to execute JNI functions are typically stalled.
5392 </description>
5393 <origin>new</origin>
5394 <capabilities>
5395 <required id="can_tag_objects"></required>
5396 </capabilities>
5397 <parameters>
5398 <param id="object">
5399 <jobject/>
5400 <description>
5401 The object
5402 </description>
5403 </param>
5404 <param id="object_reference_callback">
5405 <ptrtype>
5406 <struct>jvmtiObjectReferenceCallback</struct>
5407 </ptrtype>
5408 <description>
5409 The callback to be called to describe each
5410 object reference.
5411 </description>
5412 </param>
5413 <param id="user_data">
5414 <inbuf>
5415 <void/>
5416 <nullok><code>NULL</code> is passed as the user supplied data</nullok>
5417 </inbuf>
5418 <description>
5419 User supplied data to be passed to the callback.
5420 </description>
5421 </param>
5422 </parameters>
5423 <errors>
5424 </errors>
5425 </function>
5426
5427 <function id="IterateOverReachableObjects" num="110">
5428 <synopsis>Iterate Over Reachable Objects</synopsis>
5429 <description>
5430 This function iterates over the root objects and all objects that
5431 are directly and indirectly reachable from the root objects.
5432 The root objects comprise the set of system classes,
5433 JNI globals, references from thread stacks, and other objects used as roots
5434 for the purposes of garbage collection.
5435 <p/>
5436 For each root the <paramlink id="heap_root_callback"></paramlink>
5437 or <paramlink id="stack_ref_callback"></paramlink> callback is called.
5438 An object can be a root object for more than one reason and in that case
5439 the appropriate callback is called for each reason.
5440 <p/>
5441 For each object reference the <paramlink id="object_ref_callback"></paramlink>
5442 callback function is called to describe the object reference.
5443 The callback is called exactly once for each reference from a referrer;
5444 this is true even if there are reference cycles or multiple paths to
5445 the referrer.
5446 There may be more than one reference between a referrer and a referree,
5447 These may be distinguished by the
5448 <datalink id="jvmtiObjectReferenceCallback.reference_kind"></datalink> and
5449 <datalink id="jvmtiObjectReferenceCallback.referrer_index"></datalink>.
5450 The callback for an object will always occur after the callback for
5451 its referrer.
5452 <p/>
5453 See <functionlink id="FollowReferences"/> for the object
5454 references which are reported.
5455 <p/>
5456 Roots are always reported to the profiler before any object references
5457 are reported. In other words, the <paramlink id="object_ref_callback"></paramlink>
5458 callback will not be called until the appropriate callback has been called
5459 for all roots. If the <paramlink id="object_ref_callback"></paramlink> callback is
5460 specified as <code>NULL</code> then this function returns after
5461 reporting the root objects to the profiler.
5462 <p/>
5463 During the execution of this function the state of the heap
5464 does not change: no objects are allocated, no objects are
5465 garbage collected, and the state of objects (including
5466 held values) does not change.
5467 As a result, threads executing Java
5468 programming language code, threads attempting to resume the
5469 execution of Java programming language code, and threads
5470 attempting to execute JNI functions are typically stalled.
5471 </description>
5472 <origin>new</origin>
5473 <capabilities>
5474 <required id="can_tag_objects"></required>
5475 </capabilities>
5476 <parameters>
5477 <param id="heap_root_callback">
5478 <ptrtype>
5479 <struct>jvmtiHeapRootCallback</struct>
5480 <nullok>do not report heap roots</nullok>
5481 </ptrtype>
5482 <description>
5483 The callback function to be called for each heap root of type
5484 <code>JVMTI_HEAP_ROOT_JNI_GLOBAL</code>,
5485 <code>JVMTI_HEAP_ROOT_SYSTEM_CLASS</code>,
5486 <code>JVMTI_HEAP_ROOT_MONITOR</code>,
5487 <code>JVMTI_HEAP_ROOT_THREAD</code>, or
5488 <code>JVMTI_HEAP_ROOT_OTHER</code>.
5489 </description>
5490 </param>
5491 <param id="stack_ref_callback">
5492 <ptrtype>
5493 <struct>jvmtiStackReferenceCallback</struct>
5494 <nullok>do not report stack references</nullok>
5495 </ptrtype>
5496 <description>
5497 The callback function to be called for each heap root of
5498 <code>JVMTI_HEAP_ROOT_STACK_LOCAL</code> or
5499 <code>JVMTI_HEAP_ROOT_JNI_LOCAL</code>.
5500 </description>
5501 </param>
5502 <param id="object_ref_callback">
5503 <ptrtype>
5504 <struct>jvmtiObjectReferenceCallback</struct>
5505 <nullok>do not follow references from the root objects</nullok>
5506 </ptrtype>
5507 <description>
5508 The callback function to be called for each object reference.
5509 </description>
5510 </param>
5511 <param id="user_data">
5512 <inbuf>
5513 <void/>
5514 <nullok><code>NULL</code> is passed as the user supplied data</nullok>
5515 </inbuf>
5516 <description>
5517 User supplied data to be passed to the callback.
5518 </description>
5519 </param>
5520 </parameters>
5521 <errors>
5522 </errors>
5523 </function>
5524
5525 <function id="IterateOverHeap" num="111">
5526 <synopsis>Iterate Over Heap</synopsis>
5527 <description>
5528 Iterate over all objects in the heap. This includes both reachable and
5529 unreachable objects.
5530 <p/>
5531 The <paramlink id="object_filter"></paramlink> parameter indicates the
5532 objects for which the callback function is called. If this parameter
5533 is <code>JVMTI_HEAP_OBJECT_TAGGED</code> then the callback will only be
5534 called for every object that is tagged. If the parameter is
5535 <code>JVMTI_HEAP_OBJECT_UNTAGGED</code> then the callback will only be
5536 for objects that are not tagged. If the parameter
5537 is <code>JVMTI_HEAP_OBJECT_EITHER</code> then the callback will be
5538 called for every object in the heap, irrespective of whether it is
5539 tagged or not.
5540 <p/>
5541 During the execution of this function the state of the heap
5542 does not change: no objects are allocated, no objects are
5543 garbage collected, and the state of objects (including
5544 held values) does not change.
5545 As a result, threads executing Java
5546 programming language code, threads attempting to resume the
5547 execution of Java programming language code, and threads
5548 attempting to execute JNI functions are typically stalled.
5549 </description>
5550 <origin>new</origin>
5551 <capabilities>
5552 <required id="can_tag_objects"></required>
5553 </capabilities>
5554 <parameters>
5555 <param id="object_filter">
5556 <enum>jvmtiHeapObjectFilter</enum>
5557 <description>
5558 Indicates the objects for which the callback function is called.
5559 </description>
5560 </param>
5561 <param id="heap_object_callback">
5562 <ptrtype>
5563 <struct>jvmtiHeapObjectCallback</struct>
5564 </ptrtype>
5565 <description>
5566 The iterator function to be called for each
5567 object matching the <paramlink id="object_filter"/>.
5568 </description>
5569 </param>
5570 <param id="user_data">
5571 <inbuf>
5572 <void/>
5573 <nullok><code>NULL</code> is passed as the user supplied data</nullok>
5574 </inbuf>
5575 <description>
5576 User supplied data to be passed to the callback.
5577 </description>
5578 </param>
5579 </parameters>
5580 <errors>
5581 </errors>
5582 </function>
5583
5584 <function id="IterateOverInstancesOfClass" num="112">
5585 <synopsis>Iterate Over Instances Of Class</synopsis>
5586 <description>
5587 Iterate over all objects in the heap that are instances of the specified class.
5588 This includes direct instances of the specified class and
5589 instances of all subclasses of the specified class.
5590 This includes both reachable and unreachable objects.
5591 <p/>
5592 The <paramlink id="object_filter"></paramlink> parameter indicates the
5593 objects for which the callback function is called. If this parameter
5594 is <code>JVMTI_HEAP_OBJECT_TAGGED</code> then the callback will only be
5595 called for every object that is tagged. If the parameter is
5596 <code>JVMTI_HEAP_OBJECT_UNTAGGED</code> then the callback will only be
5597 called for objects that are not tagged. If the parameter
5598 is <code>JVMTI_HEAP_OBJECT_EITHER</code> then the callback will be
5599 called for every object in the heap, irrespective of whether it is
5600 tagged or not.
5601 <p/>
5602 During the execution of this function the state of the heap
5603 does not change: no objects are allocated, no objects are
5604 garbage collected, and the state of objects (including
5605 held values) does not change.
5606 As a result, threads executing Java
5607 programming language code, threads attempting to resume the
5608 execution of Java programming language code, and threads
5609 attempting to execute JNI functions are typically stalled.
5610 </description>
5611 <origin>new</origin>
5612 <capabilities>
5613 <required id="can_tag_objects"></required>
5614 </capabilities>
5615 <parameters>
5616 <param id="klass">
5617 <jclass/>
5618 <description>
5619 Iterate over objects of this class only.
5620 </description>
5621 </param>
5622 <param id="object_filter">
5623 <enum>jvmtiHeapObjectFilter</enum>
5624 <description>
5625 Indicates the objects for which the callback function is called.
5626 </description>
5627 </param>
5628 <param id="heap_object_callback">
5629 <ptrtype>
5630 <struct>jvmtiHeapObjectCallback</struct>
5631 </ptrtype>
5632 <description>
5633 The iterator function to be called for each
5634 <paramlink id="klass"/> instance matching
5635 the <paramlink id="object_filter"/>.
5636 </description>
5637 </param>
5638 <param id="user_data">
5639 <inbuf>
5640 <void/>
5641 <nullok><code>NULL</code> is passed as the user supplied data</nullok>
5642 </inbuf>
5643 <description>
5644 User supplied data to be passed to the callback.
5645 </description>
5646 </param>
5647 </parameters>
5648 <errors>
5649 </errors>
5650 </function>
5651
5652 </category>
5653
5654 <category id="local" label="Local Variable">
5655
5656 <intro>
5657 These functions are used to retrieve or set the value of a local variable.
5658 The variable is identified by the depth of the frame containing its
5659 value and the variable's slot number within that frame.
5660 The mapping of variables to
5661 slot numbers can be obtained with the function
5662 <functionlink id="GetLocalVariableTable"></functionlink>.
5663 </intro>
5664
5665 <function id="GetLocalObject" num="21">
5666 <synopsis>Get Local Variable - Object</synopsis>
5667 <description>
5668 This function can be used to retrieve the value of a local
5669 variable whose type is <code>Object</code> or a subclass of <code>Object</code>.
5670 </description>
5671 <origin>jvmdi</origin>
5672 <capabilities>
5673 <required id="can_access_local_variables"></required>
5674 </capabilities>
5675 <parameters>
5676 <param id="thread">
5677 <jthread null="current" frame="frame"/>
5678 <description>
5679 The thread of the frame containing the variable's value.
5680 </description>
5681 </param>
5682 <param id="depth">
5683 <jframeID thread="thread"/>
5684 <description>
5685 The depth of the frame containing the variable's value.
5686 </description>
5687 </param>
5688 <param id="slot">
5689 <jint/>
5690 <description>
5691 The variable's slot number.
5692 </description>
5693 </param>
5694 <param id="value_ptr">
5695 <outptr><jobject/></outptr>
5696 <description>
5697 On return, points to the variable's value.
5698 </description>
5699 </param>
5700 </parameters>
5701 <errors>
5702 <error id="JVMTI_ERROR_INVALID_SLOT">
5703 Invalid <code>slot</code>.
5704 </error>
5705 <error id="JVMTI_ERROR_TYPE_MISMATCH">
5706 The variable type is not
5707 <code>Object</code> or a subclass of <code>Object</code>.
5708 </error>
5709 <error id="JVMTI_ERROR_OPAQUE_FRAME">
5710 Not a visible frame
5711 </error>
5712 </errors>
5713 </function>
5714
5715 <function id="GetLocalInstance" num="155" since="1.2">
5716 <synopsis>Get Local Instance</synopsis>
5717 <description>
5718 This function can be used to retrieve the value of the local object
5719 variable at slot 0 (the "<code>this</code>" object) from non-static
5720 frames. This function can retrieve the "<code>this</code>" object from
5721 native method frames, whereas <code>GetLocalObject()</code> would
5722 return <code>JVMTI_ERROR_OPAQUE_FRAME</code> in those cases.
5723 </description>
5724 <origin>new</origin>
5725 <capabilities>
5726 <required id="can_access_local_variables"></required>
5727 </capabilities>
5728 <parameters>
5729 <param id="thread">
5730 <jthread null="current" frame="frame"/>
5731 <description>
5732 The thread of the frame containing the variable's value.
5733 </description>
5734 </param>
5735 <param id="depth">
5736 <jframeID thread="thread"/>
5737 <description>
5738 The depth of the frame containing the variable's value.
5739 </description>
5740 </param>
5741 <param id="value_ptr">
5742 <outptr><jobject/></outptr>
5743 <description>
5744 On return, points to the variable's value.
5745 </description>
5746 </param>
5747 </parameters>
5748 <errors>
5749 <error id="JVMTI_ERROR_INVALID_SLOT">
5750 If the specified frame is a static method frame.
5751 </error>
5752 </errors>
5753 </function>
5754 <function id="GetLocalInt" num="22">
5755 <synopsis>Get Local Variable - Int</synopsis>
5756 <description>
5757 This function can be used to retrieve the value of a local
5758 variable whose type is <code>int</code>,
5759 <code>short</code>, <code>char</code>, <code>byte</code>, or
5760 <code>boolean</code>.
5761 </description>
5762 <origin>jvmdi</origin>
5763 <capabilities>
5764 <required id="can_access_local_variables"></required>
5765 </capabilities>
5766 <parameters>
5767 <param id="thread">
5768 <jthread null="current" frame="frame"/>
5769 <description>
5770 The thread of the frame containing the variable's value.
5771 </description>
5772 </param>
5773 <param id="depth">
5774 <jframeID thread="thread"/>
5775 <description>
5776 The depth of the frame containing the variable's value.
5777 </description>
5778 </param>
5779 <param id="slot">
5780 <jint/>
5781 <description>
5782 The variable's slot number.
5783 </description>
5784 </param>
5785 <param id="value_ptr">
5786 <outptr><jint/></outptr>
5787 <description>
5788 On return, points to the variable's value.
5789 </description>
5790 </param>
5791 </parameters>
5792 <errors>
5793 <error id="JVMTI_ERROR_INVALID_SLOT">
5794 Invalid <code>slot</code>.
5795 </error>
5796 <error id="JVMTI_ERROR_TYPE_MISMATCH">
5797 The variable type is not
5798 <code>int</code>, <code>short</code>,
5799 <code>char</code>, <code>byte</code>, or
5800 <code>boolean</code>.
5801 </error>
5802 <error id="JVMTI_ERROR_OPAQUE_FRAME">
5803 Not a visible frame
5804 </error>
5805 </errors>
5806 </function>
5807
5808 <function id="GetLocalLong" num="23">
5809 <synopsis>Get Local Variable - Long</synopsis>
5810 <description>
5811 This function can be used to retrieve the value of a local
5812 variable whose type is <code>long</code>.
5813 </description>
5814 <origin>jvmdi</origin>
5815 <capabilities>
5816 <required id="can_access_local_variables"></required>
5817 </capabilities>
5818 <parameters>
5819 <param id="thread">
5820 <jthread null="current" frame="frame"/>
5821 <description>
5822 The thread of the frame containing the variable's value.
5823 </description>
5824 </param>
5825 <param id="depth">
5826 <jframeID thread="thread"/>
5827 <description>
5828 The depth of the frame containing the variable's value.
5829 </description>
5830 </param>
5831 <param id="slot">
5832 <jint/>
5833 <description>
5834 The variable's slot number.
5835 </description>
5836 </param>
5837 <param id="value_ptr">
5838 <outptr><jlong/></outptr>
5839 <description>
5840 On return, points to the variable's value.
5841 </description>
5842 </param>
5843 </parameters>
5844 <errors>
5845 <error id="JVMTI_ERROR_INVALID_SLOT">
5846 Invalid <code>slot</code>.
5847 </error>
5848 <error id="JVMTI_ERROR_TYPE_MISMATCH">
5849 The variable type is not <code>long</code>.
5850 </error>
5851 <error id="JVMTI_ERROR_OPAQUE_FRAME">
5852 Not a visible frame
5853 </error>
5854 </errors>
5855 </function>
5856
5857 <function id="GetLocalFloat" num="24">
5858 <synopsis>Get Local Variable - Float</synopsis>
5859 <description>
5860 This function can be used to retrieve the value of a local
5861 variable whose type is <code>float</code>.
5862 </description>
5863 <origin>jvmdi</origin>
5864 <capabilities>
5865 <required id="can_access_local_variables"></required>
5866 </capabilities>
5867 <parameters>
5868 <param id="thread">
5869 <jthread null="current" frame="frame"/>
5870 <description>
5871 The thread of the frame containing the variable's value.
5872 </description>
5873 </param>
5874 <param id="depth">
5875 <jframeID thread="thread"/>
5876 <description>
5877 The depth of the frame containing the variable's value.
5878 </description>
5879 </param>
5880 <param id="slot">
5881 <jint/>
5882 <description>
5883 The variable's slot number.
5884 </description>
5885 </param>
5886 <param id="value_ptr">
5887 <outptr><jfloat/></outptr>
5888 <description>
5889 On return, points to the variable's value.
5890 </description>
5891 </param>
5892 </parameters>
5893 <errors>
5894 <error id="JVMTI_ERROR_INVALID_SLOT">
5895 Invalid <code>slot</code>.
5896 </error>
5897 <error id="JVMTI_ERROR_TYPE_MISMATCH">
5898 The variable type is not <code>float</code>.
5899 </error>
5900 <error id="JVMTI_ERROR_OPAQUE_FRAME">
5901 Not a visible frame
5902 </error>
5903 </errors>
5904 </function>
5905
5906 <function id="GetLocalDouble" num="25">
5907 <synopsis>Get Local Variable - Double</synopsis>
5908 <description>
5909 This function can be used to retrieve the value of a local
5910 variable whose type is <code>long</code>.
5911 </description>
5912 <origin>jvmdi</origin>
5913 <capabilities>
5914 <required id="can_access_local_variables"></required>
5915 </capabilities>
5916 <parameters>
5917 <param id="thread">
5918 <jthread null="current" frame="frame"/>
5919 <description>
5920 The thread of the frame containing the variable's value.
5921 </description>
5922 </param>
5923 <param id="depth">
5924 <jframeID thread="thread"/>
5925 <description>
5926 The depth of the frame containing the variable's value.
5927 </description>
5928 </param>
5929 <param id="slot">
5930 <jint/>
5931 <description>
5932 The variable's slot number.
5933 </description>
5934 </param>
5935 <param id="value_ptr">
5936 <outptr><jdouble/></outptr>
5937 <description>
5938 On return, points to the variable's value.
5939 </description>
5940 </param>
5941 </parameters>
5942 <errors>
5943 <error id="JVMTI_ERROR_INVALID_SLOT">
5944 Invalid <code>slot</code>.
5945 </error>
5946 <error id="JVMTI_ERROR_TYPE_MISMATCH">
5947 The variable type is not <code>double</code>.
5948 </error>
5949 <error id="JVMTI_ERROR_OPAQUE_FRAME">
5950 Not a visible frame
5951 </error>
5952 </errors>
5953 </function>
5954
5955 <function id="SetLocalObject" num="26">
5956 <synopsis>Set Local Variable - Object</synopsis>
5957 <description>
5958 This function can be used to set the value of a local
5959 variable whose type is <code>Object</code> or a subclass of <code>Object</code>.
5960 </description>
5961 <origin>jvmdi</origin>
5962 <capabilities>
5963 <required id="can_access_local_variables"></required>
5964 </capabilities>
5965 <parameters>
5966 <param id="thread">
5967 <jthread null="current" frame="frame"/>
5968 <description>
5969 The thread of the frame containing the variable's value.
5970 </description>
5971 </param>
5972 <param id="depth">
5973 <jframeID thread="thread"/>
5974 <description>
5975 The depth of the frame containing the variable's value.
5976 </description>
5977 </param>
5978 <param id="slot">
5979 <jint/>
5980 <description>
5981 The variable's slot number.
5982 </description>
5983 </param>
5984 <param id="value">
5985 <jobject/>
5986 <description>
5987 The new value for the variable.
5988 </description>
5989 </param>
5990 </parameters>
5991 <errors>
5992 <error id="JVMTI_ERROR_INVALID_SLOT">
5993 Invalid <code>slot</code>.
5994 </error>
5995 <error id="JVMTI_ERROR_TYPE_MISMATCH">
5996 The variable type is not
5997 <code>Object</code> or a subclass of <code>Object</code>.
5998 </error>
5999 <error id="JVMTI_ERROR_TYPE_MISMATCH">
6000 The supplied <paramlink id="value"/> is not compatible
6001 with the variable type.
6002 </error>
6003 <error id="JVMTI_ERROR_OPAQUE_FRAME">
6004 Not a visible frame
6005 </error>
6006 </errors>
6007 </function>
6008
6009 <function id="SetLocalInt" num="27">
6010 <synopsis>Set Local Variable - Int</synopsis>
6011 <description>
6012 This function can be used to set the value of a local
6013 variable whose type is <code>int</code>,
6014 <code>short</code>, <code>char</code>, <code>byte</code>, or
6015 <code>boolean</code>.
6016 </description>
6017 <origin>jvmdi</origin>
6018 <capabilities>
6019 <required id="can_access_local_variables"></required>
6020 </capabilities>
6021 <parameters>
6022 <param id="thread">
6023 <jthread null="current" frame="frame"/>
6024 <description>
6025 The thread of the frame containing the variable's value.
6026 </description>
6027 </param>
6028 <param id="depth">
6029 <jframeID thread="thread"/>
6030 <description>
6031 The depth of the frame containing the variable's value.
6032 </description>
6033 </param>
6034 <param id="slot">
6035 <jint/>
6036 <description>
6037 The variable's slot number.
6038 </description>
6039 </param>
6040 <param id="value">
6041 <jint/>
6042 <description>
6043 The new value for the variable.
6044 </description>
6045 </param>
6046 </parameters>
6047 <errors>
6048 <error id="JVMTI_ERROR_INVALID_SLOT">
6049 Invalid <code>slot</code>.
6050 </error>
6051 <error id="JVMTI_ERROR_TYPE_MISMATCH">
6052 The variable type is not
6053 <code>int</code>, <code>short</code>,
6054 <code>char</code>, <code>byte</code>, or
6055 <code>boolean</code>.
6056 </error>
6057 <error id="JVMTI_ERROR_OPAQUE_FRAME">
6058 Not a visible frame
6059 </error>
6060 </errors>
6061 </function>
6062
6063 <function id="SetLocalLong" num="28">
6064 <synopsis>Set Local Variable - Long</synopsis>
6065 <description>
6066 This function can be used to set the value of a local
6067 variable whose type is <code>long</code>.
6068 </description>
6069 <origin>jvmdi</origin>
6070 <capabilities>
6071 <required id="can_access_local_variables"></required>
6072 </capabilities>
6073 <parameters>
6074 <param id="thread">
6075 <jthread null="current" frame="frame"/>
6076 <description>
6077 The thread of the frame containing the variable's value.
6078 </description>
6079 </param>
6080 <param id="depth">
6081 <jframeID thread="thread"/>
6082 <description>
6083 The depth of the frame containing the variable's value.
6084 </description>
6085 </param>
6086 <param id="slot">
6087 <jint/>
6088 <description>
6089 The variable's slot number.
6090 </description>
6091 </param>
6092 <param id="value">
6093 <jlong/>
6094 <description>
6095 The new value for the variable.
6096 </description>
6097 </param>
6098 </parameters>
6099 <errors>
6100 <error id="JVMTI_ERROR_INVALID_SLOT">
6101 Invalid <code>slot</code>.
6102 </error>
6103 <error id="JVMTI_ERROR_TYPE_MISMATCH">
6104 The variable type is not <code>long</code>.
6105 </error>
6106 <error id="JVMTI_ERROR_OPAQUE_FRAME">
6107 Not a visible frame
6108 </error>
6109 </errors>
6110 </function>
6111
6112 <function id="SetLocalFloat" num="29">
6113 <synopsis>Set Local Variable - Float</synopsis>
6114 <description>
6115 This function can be used to set the value of a local
6116 variable whose type is <code>float</code>.
6117 </description>
6118 <origin>jvmdi</origin>
6119 <capabilities>
6120 <required id="can_access_local_variables"></required>
6121 </capabilities>
6122 <parameters>
6123 <param id="thread">
6124 <jthread null="current" frame="frame"/>
6125 <description>
6126 The thread of the frame containing the variable's value.
6127 </description>
6128 </param>
6129 <param id="depth">
6130 <jframeID thread="thread"/>
6131 <description>
6132 The depth of the frame containing the variable's value.
6133 </description>
6134 </param>
6135 <param id="slot">
6136 <jint/>
6137 <description>
6138 The variable's slot number.
6139 </description>
6140 </param>
6141 <param id="value">
6142 <jfloat/>
6143 <description>
6144 The new value for the variable.
6145 </description>
6146 </param>
6147 </parameters>
6148 <errors>
6149 <error id="JVMTI_ERROR_INVALID_SLOT">
6150 Invalid <code>slot</code>.
6151 </error>
6152 <error id="JVMTI_ERROR_TYPE_MISMATCH">
6153 The variable type is not <code>float</code>.
6154 </error>
6155 <error id="JVMTI_ERROR_OPAQUE_FRAME">
6156 Not a visible frame
6157 </error>
6158 </errors>
6159 </function>
6160
6161 <function id="SetLocalDouble" num="30">
6162 <synopsis>Set Local Variable - Double</synopsis>
6163 <description>
6164 This function can be used to set the value of a local
6165 variable whose type is <code>double</code>.
6166 </description>
6167 <origin>jvmdi</origin>
6168 <capabilities>
6169 <required id="can_access_local_variables"></required>
6170 </capabilities>
6171 <parameters>
6172 <param id="thread">
6173 <jthread null="current" frame="frame"/>
6174 <description>
6175 The thread of the frame containing the variable's value.
6176 </description>
6177 </param>
6178 <param id="depth">
6179 <jframeID thread="thread"/>
6180 <description>
6181 The depth of the frame containing the variable's value.
6182 </description>
6183 </param>
6184 <param id="slot">
6185 <jint/>
6186 <description>
6187 The variable's slot number.
6188 </description>
6189 </param>
6190 <param id="value">
6191 <jdouble/>
6192 <description>
6193 The new value for the variable.
6194 </description>
6195 </param>
6196 </parameters>
6197 <errors>
6198 <error id="JVMTI_ERROR_INVALID_SLOT">
6199 Invalid <code>slot</code>.
6200 </error>
6201 <error id="JVMTI_ERROR_TYPE_MISMATCH">
6202 The variable type is not <code>double</code>.
6203 </error>
6204 <error id="JVMTI_ERROR_OPAQUE_FRAME">
6205 Not a visible frame
6206 </error>
6207 </errors>
6208 </function>
6209 </category>
6210
6211 <category id="breakpointCategory" label="Breakpoint">
6212
6213 <intro>
6214 </intro>
6215
6216 <function id="SetBreakpoint" num="38">
6217 <synopsis>Set Breakpoint</synopsis>
6218 <description>
6219 Set a breakpoint at the instruction indicated by
6220 <code>method</code> and <code>location</code>.
6221 An instruction can only have one breakpoint.
6222 <p/>
6223 Whenever the designated instruction is about to be executed, a
6224 <eventlink id="Breakpoint"></eventlink> event is generated.
6225 </description>
6226 <origin>jvmdi</origin>
6227 <capabilities>
6228 <required id="can_generate_breakpoint_events"></required>
6229 </capabilities>
6230 <parameters>
6231 <param id="klass">
6232 <jclass method="method"/>
6233 <description>
6234 The class in which to set the breakpoint
6235 </description>
6236 </param>
6237 <param id="method">
6238 <jmethodID class="klass"/>
6239 <description>
6240 The method in which to set the breakpoint
6241 </description>
6242 </param>
6243 <param id="location">
6244 <jlocation/>
6245 <description>
6246 the index of the instruction at which to set the breakpoint
6247
6248 </description>
6249 </param>
6250 </parameters>
6251 <errors>
6252 <error id="JVMTI_ERROR_DUPLICATE">
6253 The designated bytecode already has a breakpoint.
6254 </error>
6255 </errors>
6256 </function>
6257
6258 <function id="ClearBreakpoint" num="39">
6259 <synopsis>Clear Breakpoint</synopsis>
6260 <description>
6261 Clear the breakpoint at the bytecode indicated by
6262 <code>method</code> and <code>location</code>.
6263 </description>
6264 <origin>jvmdi</origin>
6265 <capabilities>
6266 <required id="can_generate_breakpoint_events"></required>
6267 </capabilities>
6268 <parameters>
6269 <param id="klass">
6270 <jclass method="method"/>
6271 <description>
6272 The class in which to clear the breakpoint
6273 </description>
6274 </param>
6275 <param id="method">
6276 <jmethodID class="klass"/>
6277 <description>
6278 The method in which to clear the breakpoint
6279 </description>
6280 </param>
6281 <param id="location">
6282 <jlocation/>
6283 <description>
6284 the index of the instruction at which to clear the breakpoint
6285 </description>
6286 </param>
6287 </parameters>
6288 <errors>
6289 <error id="JVMTI_ERROR_NOT_FOUND">
6290 There's no breakpoint at the designated bytecode.
6291 </error>
6292 </errors>
6293 </function>
6294
6295 </category>
6296
6297 <category id="fieldWatch" label="Watched Field">
6298
6299 <intro>
6300 </intro>
6301
6302 <function id="SetFieldAccessWatch" num="41">
6303 <synopsis>Set Field Access Watch</synopsis>
6304 <description>
6305 Generate a <eventlink id="FieldAccess"></eventlink> event
6306 when the field specified
6307 by <code>klass</code> and
6308 <code>field</code> is about to be accessed.
6309 An event will be generated for each access of the field
6310 until it is canceled with
6311 <functionlink id="ClearFieldAccessWatch"></functionlink>.
6312 Field accesses from Java programming language code or from JNI code are watched,
6313 fields modified by other means are not watched.
6314 Note that <jvmti/> users should be aware that their own field accesses
6315 will trigger the watch.
6316 A field can only have one field access watch set.
6317 Modification of a field is not considered an access--use
6318 <functionlink id="SetFieldModificationWatch"></functionlink>
6319 to monitor modifications.
6320 </description>
6321 <origin>jvmdi</origin>
6322 <capabilities>
6323 <required id="can_generate_field_access_events"></required>
6324 </capabilities>
6325 <parameters>
6326 <param id="klass">
6327 <jclass field="field"/>
6328 <description>
6329 The class containing the field to watch
6330 </description>
6331 </param>
6332 <param id="field">
6333 <jfieldID class="klass"/>
6334 <description>
6335 The field to watch
6336
6337 </description>
6338 </param>
6339 </parameters>
6340 <errors>
6341 <error id="JVMTI_ERROR_DUPLICATE">
6342 The designated field is already being watched for accesses.
6343 </error>
6344 </errors>
6345 </function>
6346
6347 <function id="ClearFieldAccessWatch" num="42">
6348 <synopsis>Clear Field Access Watch</synopsis>
6349 <description>
6350 Cancel a field access watch previously set by
6351 <functionlink id="SetFieldAccessWatch"></functionlink>, on the
6352 field specified
6353 by <code>klass</code> and
6354 <code>field</code>.
6355 </description>
6356 <origin>jvmdi</origin>
6357 <capabilities>
6358 <required id="can_generate_field_access_events"></required>
6359 </capabilities>
6360 <parameters>
6361 <param id="klass">
6362 <jclass field="field"/>
6363 <description>
6364 The class containing the field to watch
6365 </description>
6366 </param>
6367 <param id="field">
6368 <jfieldID class="klass"/>
6369 <description>
6370 The field to watch
6371
6372 </description>
6373 </param>
6374 </parameters>
6375 <errors>
6376 <error id="JVMTI_ERROR_NOT_FOUND">
6377 The designated field is not being watched for accesses.
6378 </error>
6379 </errors>
6380 </function>
6381
6382 <function id="SetFieldModificationWatch" num="43">
6383 <synopsis>Set Field Modification Watch</synopsis>
6384 <description>
6385 Generate a <eventlink id="FieldModification"></eventlink> event
6386 when the field specified
6387 by <code>klass</code> and
6388 <code>field</code> is about to be modified.
6389 An event will be generated for each modification of the field
6390 until it is canceled with
6391 <functionlink id="ClearFieldModificationWatch"></functionlink>.
6392 Field modifications from Java programming language code or from JNI code are watched,
6393 fields modified by other means are not watched.
6394 Note that <jvmti/> users should be aware that their own field modifications
6395 will trigger the watch.
6396 A field can only have one field modification watch set.
6397 </description>
6398 <origin>jvmdi</origin>
6399 <capabilities>
6400 <required id="can_generate_field_modification_events"></required>
6401 </capabilities>
6402 <parameters>
6403 <param id="klass">
6404 <jclass field="field"/>
6405 <description>
6406 The class containing the field to watch
6407 </description>
6408 </param>
6409 <param id="field">
6410 <jfieldID class="klass"/>
6411 <description>
6412 The field to watch
6413
6414 </description>
6415 </param>
6416 </parameters>
6417 <errors>
6418 <error id="JVMTI_ERROR_DUPLICATE">
6419 The designated field is already being watched for modifications.
6420 </error>
6421 </errors>
6422 </function>
6423
6424 <function id="ClearFieldModificationWatch" num="44">
6425 <synopsis>Clear Field Modification Watch</synopsis>
6426 <description>
6427
6428 Cancel a field modification watch previously set by
6429 <functionlink id="SetFieldModificationWatch"></functionlink>, on the
6430 field specified
6431 by <code>klass</code> and
6432 <code>field</code>.
6433 </description>
6434 <origin>jvmdi</origin>
6435 <capabilities>
6436 <required id="can_generate_field_modification_events"></required>
6437 </capabilities>
6438 <parameters>
6439 <param id="klass">
6440 <jclass field="field"/>
6441 <description>
6442 The class containing the field to watch
6443 </description>
6444 </param>
6445 <param id="field">
6446 <jfieldID class="klass"/>
6447 <description>
6448 The field to watch
6449
6450 </description>
6451 </param>
6452 </parameters>
6453 <errors>
6454 <error id="JVMTI_ERROR_NOT_FOUND">
6455 The designated field is not being watched for modifications.
6456 </error>
6457 </errors>
6458 </function>
6459 </category>
6460
6461 <category id="class" label="Class">
6462
6463 <intro>
6464 </intro>
6465
6466 <function id="GetLoadedClasses" jkernel="yes" num="78">
6467 <synopsis>Get Loaded Classes</synopsis>
6468 <description>
6469 Return an array of all classes loaded in the virtual machine.
6470 The number of classes in the array is returned via
6471 <code>class_count_ptr</code>, and the array itself via
6472 <code>classes_ptr</code>.
6473 <p/>
6474 Array classes of all types (including arrays of primitive types) are
6475 included in the returned list. Primitive classes (for example,
6476 <code>java.lang.Integer.TYPE</code>) are <i>not</i> included in this list.
6477 </description>
6478 <origin>jvmdi</origin>
6479 <capabilities>
6480 </capabilities>
6481 <parameters>
6482 <param id="class_count_ptr">
6483 <outptr><jint/></outptr>
6484 <description>
6485 On return, points to the number of classes.
6486 </description>
6487 </param>
6488 <param id="classes_ptr">
6489 <allocbuf outcount="class_count_ptr"><jclass/></allocbuf>
6490 <description>
6491 On return, points to an array of references, one
6492 for each class.
6493 </description>
6494 </param>
6495 </parameters>
6496 <errors>
6497 </errors>
6498 </function>
6499
6500 <function id="GetClassLoaderClasses" jkernel="yes" num="79">
6501 <synopsis>Get Classloader Classes</synopsis>
6502 <description>
6503 Returns an array of those classes for which this class loader has
6504 been recorded as an initiating loader. Each
6505 class in the returned array was created by this class loader,
6506 either by defining it directly or by delegation to another class loader.
6507 See <vmspec chapter="5.3"/>.
6508 <p/>
6509 For JDK version 1.1 implementations that don't
6510 recognize the distinction between initiating and defining class loaders,
6511 this function should return all classes loaded in the virtual machine.
6512 The number of classes in the array is returned via
6513 <code>class_count_ptr</code>, and the array itself via
6514 <code>classes_ptr</code>.
6515 </description>
6516 <origin>jvmdi</origin>
6517 <capabilities>
6518 </capabilities>
6519 <parameters>
6520 <param id="initiating_loader">
6521 <ptrtype>
6522 <jobject/>
6523 <nullok>the classes initiated by the bootstrap loader will be returned</nullok>
6524 </ptrtype>
6525 <description>
6526 An initiating class loader.
6527 </description>
6528 </param>
6529 <param id="class_count_ptr">
6530 <outptr><jint/></outptr>
6531 <description>
6532 On return, points to the number of classes.
6533 </description>
6534 </param>
6535 <param id="classes_ptr">
6536 <allocbuf outcount="class_count_ptr"><jclass/></allocbuf>
6537 <description>
6538 On return, points to an array of references, one
6539 for each class.
6540 </description>
6541 </param>
6542 </parameters>
6543 <errors>
6544 </errors>
6545 </function>
6546
6547 <function id="GetClassSignature" phase="start" num="48">
6548 <synopsis>Get Class Signature</synopsis>
6549 <description>
6550 For the class indicated by <code>klass</code>, return the
6551 <externallink id="http://docs.oracle.com/javase/7/docs/technotes/guides/jni/spec/types.html#wp16432">JNI
6552 type signature</externallink>
6553 and the generic signature of the class.
6554 For example, <code>java.util.List</code> is <code>"Ljava/util/List;"</code>
6555 and <code>int[]</code> is <code>"[I"</code>
6556 The returned name for primitive classes
6557 is the type signature character of the corresponding primitive type.
6558 For example, <code>java.lang.Integer.TYPE</code> is <code>"I"</code>.
6559 </description>
6560 <origin>jvmdiClone</origin>
6561 <capabilities>
6562 </capabilities>
6563 <parameters>
6564 <param id="klass">
6565 <jclass/>
6566 <description>
6567 The class to query.
6568 </description>
6569 </param>
6570 <param id="signature_ptr">
6571 <allocbuf>
6572 <char/>
6573 <nullok>the signature is not returned</nullok>
6574 </allocbuf>
6575 <description>
6576 On return, points to the JNI type signature of the class, encoded as a
6577 <internallink id="mUTF">modified UTF-8</internallink> string.
6578 </description>
6579 </param>
6580 <param id="generic_ptr">
6581 <allocbuf>
6582 <char/>
6583 <nullok>the generic signature is not returned</nullok>
6584 </allocbuf>
6585 <description>
6586 On return, points to the generic signature of the class, encoded as a
6587 <internallink id="mUTF">modified UTF-8</internallink> string.
6588 If there is no generic signature attribute for the class, then,
6589 on return, points to <code>NULL</code>.
6590 </description>
6591 </param>
6592 </parameters>
6593 <errors>
6594 </errors>
6595 </function>
6596
6597 <function id="GetClassStatus" phase="start" num="49">
6598 <synopsis>Get Class Status</synopsis>
6599 <description>
6600 Get the status of the class. Zero or more of the following bits can be
6601 set.
6602 <constants id="jvmtiClassStatus" label="Class Status Flags" kind="bits">
6603 <constant id="JVMTI_CLASS_STATUS_VERIFIED" num="1">
6604 Class bytecodes have been verified
6605 </constant>
6606 <constant id="JVMTI_CLASS_STATUS_PREPARED" num="2">
6607 Class preparation is complete
6608 </constant>
6609 <constant id="JVMTI_CLASS_STATUS_INITIALIZED" num="4">
6610 Class initialization is complete. Static initializer has been run.
6611 </constant>
6612 <constant id="JVMTI_CLASS_STATUS_ERROR" num="8">
6613 Error during initialization makes class unusable
6614 </constant>
6615 <constant id="JVMTI_CLASS_STATUS_ARRAY" num="16">
6616 Class is an array. If set, all other bits are zero.
6617 </constant>
6618 <constant id="JVMTI_CLASS_STATUS_PRIMITIVE" num="32">
6619 Class is a primitive class (for example, <code>java.lang.Integer.TYPE</code>).
6620 If set, all other bits are zero.
6621 </constant>
6622 </constants>
6623 </description>
6624 <origin>jvmdi</origin>
6625 <capabilities>
6626 </capabilities>
6627 <parameters>
6628 <param id="klass">
6629 <jclass/>
6630 <description>
6631 The class to query.
6632 </description>
6633 </param>
6634 <param id="status_ptr">
6635 <outptr><jint/></outptr>
6636 <description>
6637 On return, points to the current state of this class as one or
6638 more of the <internallink id="jvmtiClassStatus">class status flags</internallink>.
6639 </description>
6640 </param>
6641 </parameters>
6642 <errors>
6643 </errors>
6644 </function>
6645
6646 <function id="GetSourceFileName" phase="start" num="50">
6647 <synopsis>Get Source File Name</synopsis>
6648 <description>
6649 For the class indicated by <code>klass</code>, return the source file
6650 name via <code>source_name_ptr</code>. The returned string
6651 is a file name only and never contains a directory name.
6652 <p/>
6653 For primitive classes (for example, <code>java.lang.Integer.TYPE</code>)
6654 and for arrays this function returns
6655 <errorlink id="JVMTI_ERROR_ABSENT_INFORMATION"></errorlink>.
6656 </description>
6657 <origin>jvmdi</origin>
6658 <capabilities>
6659 <required id="can_get_source_file_name"></required>
6660 </capabilities>
6661 <parameters>
6662 <param id="klass">
6663 <jclass/>
6664 <description>
6665 The class to query.
6666 </description>
6667 </param>
6668 <param id="source_name_ptr">
6669 <allocbuf><char/></allocbuf>
6670 <description>
6671 On return, points to the class's source file name, encoded as a
6672 <internallink id="mUTF">modified UTF-8</internallink> string.
6673 </description>
6674 </param>
6675 </parameters>
6676 <errors>
6677 <error id="JVMTI_ERROR_ABSENT_INFORMATION">
6678 Class information does not include a source file name. This includes
6679 cases where the class is an array class or primitive class.
6680 </error>
6681 </errors>
6682 </function>
6683
6684 <function id="GetClassModifiers" phase="start" num="51">
6685 <synopsis>Get Class Modifiers</synopsis>
6686 <description>
6687 For the class indicated by <code>klass</code>, return the access
6688 flags
6689 via <code>modifiers_ptr</code>.
6690 Access flags are defined in <vmspec chapter="4"/>.
6691 <p/>
6692 If the class is an array class, then its public, private, and protected
6693 modifiers are the same as those of its component type. For arrays of
6694 primitives, this component type is represented by one of the primitive
6695 classes (for example, <code>java.lang.Integer.TYPE</code>).
6696 <p/>
6697 If the class is a primitive class, its public modifier is always true,
6698 and its protected and private modifiers are always false.
6699 <p/>
6700 If the class is an array class or a primitive class then its final
6701 modifier is always true and its interface modifier is always false.
6702 The values of its other modifiers are not determined by this specification.
6703
6704 </description>
6705 <origin>jvmdi</origin>
6706 <capabilities>
6707 </capabilities>
6708 <parameters>
6709 <param id="klass">
6710 <jclass/>
6711 <description>
6712 The class to query.
6713 </description>
6714 </param>
6715 <param id="modifiers_ptr">
6716 <outptr><jint/></outptr>
6717 <description>
6718 On return, points to the current access flags of this class.
6719
6720 </description>
6721 </param>
6722 </parameters>
6723 <errors>
6724 </errors>
6725 </function>
6726
6727 <function id="GetClassMethods" phase="start" num="52">
6728 <synopsis>Get Class Methods</synopsis>
6729 <description>
6730 For the class indicated by <code>klass</code>, return a count of
6731 methods via <code>method_count_ptr</code> and a list of
6732 method IDs via <code>methods_ptr</code>. The method list contains
6733 constructors and static initializers as well as true methods.
6734 Only directly declared methods are returned (not inherited methods).
6735 An empty method list is returned for array classes and primitive classes
6736 (for example, <code>java.lang.Integer.TYPE</code>).
6737 </description>
6738 <origin>jvmdi</origin>
6739 <capabilities>
6740 <capability id="can_maintain_original_method_order"/>
6741 </capabilities>
6742 <parameters>
6743 <param id="klass">
6744 <jclass/>
6745 <description>
6746 The class to query.
6747 </description>
6748 </param>
6749 <param id="method_count_ptr">
6750 <outptr><jint/></outptr>
6751 <description>
6752 On return, points to the number of methods declared in this class.
6753 </description>
6754 </param>
6755 <param id="methods_ptr">
6756 <allocbuf outcount="method_count_ptr"><jmethodID class="klass"/></allocbuf>
6757 <description>
6758 On return, points to the method ID array.
6759 </description>
6760 </param>
6761 </parameters>
6762 <errors>
6763 <error id="JVMTI_ERROR_CLASS_NOT_PREPARED">
6764 <paramlink id="klass"></paramlink> is not prepared.
6765 </error>
6766 </errors>
6767 </function>
6768
6769 <function id="GetClassFields" phase="start" num="53">
6770 <synopsis>Get Class Fields</synopsis>
6771 <description>
6772 For the class indicated by <code>klass</code>, return a count of fields
6773 via <code>field_count_ptr</code> and a list of field IDs via
6774 <code>fields_ptr</code>.
6775 Only directly declared fields are returned (not inherited fields).
6776 Fields are returned in the order they occur in the class file.
6777 An empty field list is returned for array classes and primitive classes
6778 (for example, <code>java.lang.Integer.TYPE</code>).
6779 Use JNI to determine the length of an array.
6780 </description>
6781 <origin>jvmdi</origin>
6782 <capabilities>
6783 </capabilities>
6784 <parameters>
6785 <param id="klass">
6786 <jclass/>
6787 <description>
6788 The class to query.
6789 </description>
6790 </param>
6791 <param id="field_count_ptr">
6792 <outptr><jint/></outptr>
6793 <description>
6794 On return, points to the number of fields declared in this class.
6795 </description>
6796 </param>
6797 <param id="fields_ptr">
6798 <allocbuf outcount="field_count_ptr"><jfieldID/></allocbuf>
6799 <description>
6800 On return, points to the field ID array.
6801 </description>
6802 </param>
6803 </parameters>
6804 <errors>
6805 <error id="JVMTI_ERROR_CLASS_NOT_PREPARED">
6806 <paramlink id="klass"></paramlink> is not prepared.
6807 </error>
6808 </errors>
6809 </function>
6810
6811 <function id="GetImplementedInterfaces" phase="start" num="54">
6812 <synopsis>Get Implemented Interfaces</synopsis>
6813 <description>
6814 Return the direct super-interfaces of this class. For a class, this
6815 function returns the interfaces declared in its <code>implements</code>
6816 clause. For an interface, this function returns the interfaces declared in
6817 its <code>extends</code> clause.
6818 An empty interface list is returned for array classes and primitive classes
6819 (for example, <code>java.lang.Integer.TYPE</code>).
6820 </description>
6821 <origin>jvmdi</origin>
6822 <capabilities>
6823 </capabilities>
6824 <parameters>
6825 <param id="klass">
6826 <jclass/>
6827 <description>
6828 The class to query.
6829 </description>
6830 </param>
6831 <param id="interface_count_ptr">
6832 <outptr><jint/></outptr>
6833 <description>
6834 On return, points to the number of interfaces.
6835 </description>
6836 </param>
6837 <param id="interfaces_ptr">
6838 <allocbuf outcount="interface_count_ptr"><jclass/></allocbuf>
6839 <description>
6840 On return, points to the interface array.
6841 </description>
6842 </param>
6843 </parameters>
6844 <errors>
6845 <error id="JVMTI_ERROR_CLASS_NOT_PREPARED">
6846 <paramlink id="klass"></paramlink> is not prepared.
6847 </error>
6848 </errors>
6849 </function>
6850
6851 <function id="GetClassVersionNumbers" phase="start" num="145" since="1.1">
6852 <synopsis>Get Class Version Numbers</synopsis>
6853 <description>
6854 For the class indicated by <code>klass</code>,
6855 return the minor and major version numbers,
6856 as defined in
6857 <vmspec chapter="4"/>.
6858 </description>
6859 <origin>new</origin>
6860 <capabilities>
6861 </capabilities>
6862 <parameters>
6863 <param id="klass">
6864 <jclass/>
6865 <description>
6866 The class to query.
6867 </description>
6868 </param>
6869 <param id="minor_version_ptr">
6870 <outptr><jint/></outptr>
6871 <description>
6872 On return, points to the value of the
6873 <code>minor_version</code> item of the
6874 Class File Format.
6875 Note: to be consistent with the Class File Format,
6876 the minor version number is the first parameter.
6877 </description>
6878 </param>
6879 <param id="major_version_ptr">
6880 <outptr><jint/></outptr>
6881 <description>
6882 On return, points to the value of the
6883 <code>major_version</code> item of the
6884 Class File Format.
6885 </description>
6886 </param>
6887 </parameters>
6888 <errors>
6889 <error id="JVMTI_ERROR_ABSENT_INFORMATION">
6890 The class is a primitive or array class.
6891 </error>
6892 </errors>
6893 </function>
6894
6895 <function id="GetConstantPool" phase="start" num="146" since="1.1">
6896 <synopsis>Get Constant Pool</synopsis>
6897 <description>
6898 For the class indicated by <code>klass</code>,
6899 return the raw bytes of the constant pool in the format of the
6900 <code>constant_pool</code> item of
6901 <vmspec chapter="4"/>.
6902 The format of the constant pool may differ between versions
6903 of the Class File Format, so, the
6904 <functionlink id="GetClassVersionNumbers">minor and major
6905 class version numbers</functionlink> should be checked for
6906 compatibility.
6907 <p/>
6908 The returned constant pool might not have the same layout or
6909 contents as the constant pool in the defining class file.
6910 The constant pool returned by GetConstantPool() may have
6911 more or fewer entries than the defining constant pool.
6912 Entries may be in a different order.
6913 The constant pool returned by GetConstantPool() will match the
6914 constant pool used by
6915 <functionlink id="GetBytecodes">GetBytecodes()</functionlink>.
6916 That is, the bytecodes returned by GetBytecodes() will have
6917 constant pool indices which refer to constant pool entries returned
6918 by GetConstantPool().
6919 Note that since <functionlink id="RetransformClasses"/>
6920 and <functionlink id="RedefineClasses"/> can change
6921 the constant pool, the constant pool returned by this function
6922 can change accordingly. Thus, the correspondence between
6923 GetConstantPool() and GetBytecodes() does not hold if there
6924 is an intervening class retransformation or redefinition.
6925 The value of a constant pool entry used by a given bytecode will
6926 match that of the defining class file (even if the indices don't match).
6927 Constant pool entries which are not used directly or indirectly by
6928 bytecodes (for example, UTF-8 strings associated with annotations) are
6929 not required to exist in the returned constant pool.
6930 </description>
6931 <origin>new</origin>
6932 <capabilities>
6933 <required id="can_get_constant_pool"></required>
6934 </capabilities>
6935 <parameters>
6936 <param id="klass">
6937 <jclass/>
6938 <description>
6939 The class to query.
6940 </description>
6941 </param>
6942 <param id="constant_pool_count_ptr">
6943 <outptr><jint/></outptr>
6944 <description>
6945 On return, points to the number of entries
6946 in the constant pool table plus one.
6947 This corresponds to the <code>constant_pool_count</code>
6948 item of the Class File Format.
6949 </description>
6950 </param>
6951 <param id="constant_pool_byte_count_ptr">
6952 <outptr><jint/></outptr>
6953 <description>
6954 On return, points to the number of bytes
6955 in the returned raw constant pool.
6956 </description>
6957 </param>
6958 <param id="constant_pool_bytes_ptr">
6959 <allocbuf outcount="constant_pool_byte_count_ptr"><uchar/></allocbuf>
6960 <description>
6961 On return, points to the raw constant pool, that is the bytes
6962 defined by the <code>constant_pool</code> item of the
6963 Class File Format
6964 </description>
6965 </param>
6966 </parameters>
6967 <errors>
6968 <error id="JVMTI_ERROR_ABSENT_INFORMATION">
6969 The class is a primitive or array class.
6970 </error>
6971 </errors>
6972 </function>
6973
6974 <function id="IsInterface" phase="start" num="55">
6975 <synopsis>Is Interface</synopsis>
6976 <description>
6977 Determines whether a class object reference represents an interface.
6978 The <code>jboolean</code> result is
6979 <code>JNI_TRUE</code> if the "class" is actually an interface,
6980 <code>JNI_FALSE</code> otherwise.
6981 </description>
6982 <origin>jvmdi</origin>
6983 <capabilities>
6984 </capabilities>
6985 <parameters>
6986 <param id="klass">
6987 <jclass/>
6988 <description>
6989 The class to query.
6990 </description>
6991 </param>
6992 <param id="is_interface_ptr">
6993 <outptr><jboolean/></outptr>
6994 <description>
6995 On return, points to the boolean result of this function.
6996
6997 </description>
6998 </param>
6999 </parameters>
7000 <errors>
7001 </errors>
7002 </function>
7003
7004 <function id="IsArrayClass" phase="start" num="56">
7005 <synopsis>Is Array Class</synopsis>
7006 <description>
7007 Determines whether a class object reference represents an array.
7008 The <code>jboolean</code> result is
7009 <code>JNI_TRUE</code> if the class is an array,
7010 <code>JNI_FALSE</code> otherwise.
7011 </description>
7012 <origin>jvmdi</origin>
7013 <capabilities>
7014 </capabilities>
7015 <parameters>
7016 <param id="klass">
7017 <jclass/>
7018 <description>
7019 The class to query.
7020 </description>
7021 </param>
7022 <param id="is_array_class_ptr">
7023 <outptr><jboolean/></outptr>
7024 <description>
7025 On return, points to the boolean result of this function.
7026
7027 </description>
7028 </param>
7029 </parameters>
7030 <errors>
7031 </errors>
7032 </function>
7033
7034 <function id="IsModifiableClass" jkernel="yes" phase="start" num="45" since="1.1">
7035 <synopsis>Is Modifiable Class</synopsis>
7036 <description>
7037 Determines whether a class is modifiable.
7038 If a class is modifiable (<paramlink id="is_modifiable_class_ptr"/>
7039 returns <code>JNI_TRUE</code>) the class can be
7040 redefined with <functionlink id="RedefineClasses"/> (assuming
7041 the agent possesses the
7042 <fieldlink id="can_redefine_classes" struct="jvmtiCapabilities"/>
7043 capability) or
7044 retransformed with <functionlink id="RetransformClasses"/> (assuming
7045 the agent possesses the
7046 <fieldlink id="can_retransform_classes" struct="jvmtiCapabilities"/>
7047 capability).
7048 If a class is not modifiable (<paramlink id="is_modifiable_class_ptr"/>
7049 returns <code>JNI_FALSE</code>) the class can be neither
7050 redefined nor retransformed.
7051 <p/>
7052 Primitive classes (for example, <code>java.lang.Integer.TYPE</code>)
7053 and array classes are never modifiable.
7054 <p/>
7055 </description>
7056 <origin>new</origin>
7057 <capabilities>
7058 <capability id="can_redefine_any_class">
7059 If possessed then all classes (except primitive and array classes)
7060 are modifiable.
7061 </capability>
7062 <capability id="can_redefine_classes">
7063 No effect on the result of the function.
7064 But must additionally be possessed to modify the class with
7065 <functionlink id="RedefineClasses"/>.
7066 </capability>
7067 <capability id="can_retransform_classes">
7068 No effect on the result of the function.
7069 But must additionally be possessed to modify the class with
7070 <functionlink id="RetransformClasses"/>.
7071 </capability>
7072 </capabilities>
7073 <parameters>
7074 <param id="klass">
7075 <jclass/>
7076 <description>
7077 The class to query.
7078 </description>
7079 </param>
7080 <param id="is_modifiable_class_ptr">
7081 <outptr><jboolean/></outptr>
7082 <description>
7083 On return, points to the boolean result of this function.
7084 </description>
7085 </param>
7086 </parameters>
7087 <errors>
7088 </errors>
7089 </function>
7090
7091 <function id="GetClassLoader" phase="start" num="57">
7092 <synopsis>Get Class Loader</synopsis>
7093 <description>
7094 For the class indicated by <code>klass</code>, return via
7095 <code>classloader_ptr</code> a reference to the class loader for the
7096 class.
7097 </description>
7098 <origin>jvmdi</origin>
7099 <capabilities>
7100 </capabilities>
7101 <parameters>
7102 <param id="klass">
7103 <jclass/>
7104 <description>
7105 The class to query.
7106 </description>
7107 </param>
7108 <param id="classloader_ptr">
7109 <outptr><jobject/></outptr>
7110 <description>
7111 On return, points to the class loader that loaded
7112 this class.
7113 If the class was not created by a class loader
7114 or if the class loader is the bootstrap class loader,
7115 points to <code>NULL</code>.
7116 </description>
7117 </param>
7118 </parameters>
7119 <errors>
7120 </errors>
7121
7122 </function>
7123
7124 <function id="GetSourceDebugExtension" phase="start" num="90">
7125 <synopsis>Get Source Debug Extension</synopsis>
7126 <description>
7127 For the class indicated by <code>klass</code>, return the debug
7128 extension via <code>source_debug_extension_ptr</code>.
7129 The returned string
7130 contains exactly the debug extension information present in the
7131 class file of <code>klass</code>.
7132 </description>
7133 <origin>jvmdi</origin>
7134 <capabilities>
7135 <required id="can_get_source_debug_extension"></required>
7136 </capabilities>
7137 <parameters>
7138 <param id="klass">
7139 <jclass/>
7140 <description>
7141 The class to query.
7142 </description>
7143 </param>
7144 <param id="source_debug_extension_ptr">
7145 <allocbuf><char/></allocbuf>
7146 <description>
7147 On return, points to the class's debug extension, encoded as a
7148 <internallink id="mUTF">modified UTF-8</internallink> string.
7149 </description>
7150 </param>
7151 </parameters>
7152 <errors>
7153 <error id="JVMTI_ERROR_ABSENT_INFORMATION">
7154 Class information does not include a debug extension.
7155 </error>
7156 </errors>
7157 </function>
7158
7159 <function id="RetransformClasses" jkernel="yes" num="152" since="1.1">
7160 <synopsis>Retransform Classes</synopsis>
7161 <description>
7162 This function facilitates the
7163 <internallink id="bci">bytecode instrumentation</internallink>
7164 of already loaded classes.
7165 To replace the class definition without reference to the existing
7166 bytecodes, as one might do when recompiling from source for
7167 fix-and-continue debugging, <functionlink id="RedefineClasses"/>
7168 function should be used instead.
7169 <p/>
7170 When classes are initially loaded or when they are
7171 <functionlink id="RedefineClasses">redefined</functionlink>,
7172 the initial class file bytes can be transformed with the
7173 <eventlink id="ClassFileLoadHook"/> event.
7174 This function reruns the transformation process
7175 (whether or not a transformation has previously occurred).
7176 This retransformation follows these steps:
7177 <ul>
7178 <li>starting from the initial class file bytes
7179 </li>
7180 <li>for each <fieldlink id="can_retransform_classes"
7181 struct="jvmtiCapabilities">retransformation
7182 incapable</fieldlink>
7183 agent which received a
7184 <code>ClassFileLoadHook</code> event during the previous
7185 load or redefine, the bytes it returned
7186 (via the <code>new_class_data</code> parameter)
7187 are reused as the output of the transformation;
7188 note that this is equivalent to reapplying
7189 the previous transformation, unaltered. except that
7190 the <code>ClassFileLoadHook</code> event
7191 is <b>not</b> sent to these agents
7192 </li>
7193 <li>for each <fieldlink id="can_retransform_classes"
7194 struct="jvmtiCapabilities">retransformation
7195 capable</fieldlink>
7196 agent, the <code>ClassFileLoadHook</code> event is sent,
7197 allowing a new transformation to be applied
7198 </li>
7199 <li>the transformed class file bytes are installed as the new
7200 definition of the class
7201 </li>
7202 </ul>
7203 See the <eventlink id="ClassFileLoadHook"/> event for more details.
7204 <p/>
7205 The initial class file bytes represent the bytes passed to
7206 <code>ClassLoader.defineClass</code>
7207 or <code>RedefineClasses</code> (before any transformations
7208 were applied), however they may not exactly match them.
7209 The constant pool may differ in ways described in
7210 <functionlink id="GetConstantPool"/>.
7211 Constant pool indices in the bytecodes of methods will correspond.
7212 Some attributes may not be present.
7213 Where order is not meaningful, for example the order of methods,
7214 order may not be preserved.
7215 <p/>
7216 Retransformation can cause new versions of methods to be installed.
7217 Old method versions may become
7218 <internallink id="obsoleteMethods">obsolete</internallink>
7219 The new method version will be used on new invokes.
7220 If a method has active stack frames, those active frames continue to
7221 run the bytecodes of the original method version.
7222 <p/>
7223 This function does not cause any initialization except that which
7224 would occur under the customary JVM semantics.
7225 In other words, retransforming a class does not cause its initializers to be
7226 run. The values of static fields will remain as they were
7227 prior to the call.
7228 <p/>
7229 Threads need not be suspended.
7230 <p/>
7231 All breakpoints in the class are cleared.
7232 <p/>
7233 All attributes are updated.
7234 <p/>
7235 Instances of the retransformed class are not affected -- fields retain their
7236 previous values.
7237 <functionlink id="GetTag">Tags</functionlink> on the instances are
7238 also unaffected.
7239 <p/>
7240 In response to this call, no events other than the
7241 <eventlink id="ClassFileLoadHook"/> event
7242 will be sent.
7243 <p/>
7244 The retransformation may change method bodies, the constant pool and attributes.
7245 The retransformation must not add, remove or rename fields or methods, change the
7246 signatures of methods, change modifiers, or change inheritance.
7247 These restrictions may be lifted in future versions.
7248 See the error return description below for information on error codes
7249 returned if an unsupported retransformation is attempted.
7250 The class file bytes are not verified or installed until they have passed
7251 through the chain of <eventlink id="ClassFileLoadHook"/> events, thus the
7252 returned error code reflects the result of the transformations.
7253 If any error code is returned other than <code>JVMTI_ERROR_NONE</code>,
7254 none of the classes to be retransformed will have a new definition installed.
7255 When this function returns (with the error code of <code>JVMTI_ERROR_NONE</code>)
7256 all of the classes to be retransformed will have their new definitions installed.
7257 </description>
7258 <origin>new</origin>
7259 <capabilities>
7260 <required id="can_retransform_classes"></required>
7261 <capability id="can_retransform_any_class"></capability>
7262 </capabilities>
7263 <parameters>
7264 <param id="class_count">
7265 <jint min="0"/>
7266 <description>
7267 The number of classes to be retransformed.
7268 </description>
7269 </param>
7270 <param id="classes">
7271 <inbuf incount="class_count"><jclass/></inbuf>
7272 <description>
7273 The array of classes to be retransformed.
7274 </description>
7275 </param>
7276 </parameters>
7277 <errors>
7278 <error id="JVMTI_ERROR_UNMODIFIABLE_CLASS">
7279 One of the <paramlink id="classes"/> cannot be modified.
7280 See <functionlink id="IsModifiableClass"/>.
7281 </error>
7282 <error id="JVMTI_ERROR_INVALID_CLASS">
7283 One of the <paramlink id="classes"/> is not a valid class.
7284 </error>
7285 <error id="JVMTI_ERROR_UNSUPPORTED_VERSION">
7286 A retransformed class file has a version number not supported by this VM.
7287 </error>
7288 <error id="JVMTI_ERROR_INVALID_CLASS_FORMAT">
7289 A retransformed class file is malformed (The VM would return a <code>ClassFormatError</code>).
7290 </error>
7291 <error id="JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION">
7292 The retransformed class file definitions would lead to a circular definition
7293 (the VM would return a <code>ClassCircularityError</code>).
7294 </error>
7295 <error id="JVMTI_ERROR_FAILS_VERIFICATION">
7296 The retransformed class file bytes fail verification.
7297 </error>
7298 <error id="JVMTI_ERROR_NAMES_DONT_MATCH">
7299 The class name defined in a retransformed class file is
7300 different from the name in the old class object.
7301 </error>
7302 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED">
7303 A retransformed class file would require adding a method.
7304 </error>
7305 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED">
7306 A retransformed class file changes a field.
7307 </error>
7308 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED">
7309 A direct superclass is different for a retransformed class file,
7310 or the set of directly implemented
7311 interfaces is different.
7312 </error>
7313 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED">
7314 A retransformed class file does not declare a method
7315 declared in the old class version.
7316 </error>
7317 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED">
7318 A retransformed class file has different class modifiers.
7319 </error>
7320 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED">
7321 A method in the retransformed class file has different modifiers
7322 than its counterpart in the old class version.
7323 </error>
7324 </errors>
7325 </function>
7326
7327 <function id="RedefineClasses" jkernel="yes" num="87">
7328 <synopsis>Redefine Classes</synopsis>
7329 <typedef id="jvmtiClassDefinition" label="Class redefinition description">
7330 <field id="klass">
7331 <jclass/>
7332 <description>
7333 Class object for this class
7334 </description>
7335 </field>
7336 <field id="class_byte_count">
7337 <jint/>
7338 <description>
7339 Number of bytes defining class (below)
7340 </description>
7341 </field>
7342 <field id="class_bytes">
7343 <inbuf incount="class_byte_count"><uchar/></inbuf>
7344 <description>
7345 Bytes defining class (in <vmspec chapter="4"/>)
7346 </description>
7347 </field>
7348 </typedef>
7349 <description>
7350 All classes given are redefined according to the definitions
7351 supplied.
7352 This function is used to replace the definition of a class
7353 with a new definition, as might be needed in fix-and-continue
7354 debugging.
7355 Where the existing class file bytes are to be transformed, for
7356 example in
7357 <internallink id="bci">bytecode instrumentation</internallink>,
7358 <functionlink id="RetransformClasses"/> should be used.
7359 <p/>
7360 Redefinition can cause new versions of methods to be installed.
7361 Old method versions may become
7362 <internallink id="obsoleteMethods">obsolete</internallink>
7363 The new method version will be used on new invokes.
7364 If a method has active stack frames, those active frames continue to
7365 run the bytecodes of the original method version.
7366 If resetting of stack frames is desired, use
7367 <functionlink id="PopFrame"></functionlink>
7368 to pop frames with obsolete method versions.
7369 <p/>
7370 This function does not cause any initialization except that which
7371 would occur under the customary JVM semantics.
7372 In other words, redefining a class does not cause its initializers to be
7373 run. The values of static fields will remain as they were
7374 prior to the call.
7375 <p/>
7376 Threads need not be suspended.
7377 <p/>
7378 All breakpoints in the class are cleared.
7379 <p/>
7380 All attributes are updated.
7381 <p/>
7382 Instances of the redefined class are not affected -- fields retain their
7383 previous values.
7384 <functionlink id="GetTag">Tags</functionlink> on the instances are
7385 also unaffected.
7386 <p/>
7387 In response to this call, the <jvmti/> event
7388 <eventlink id="ClassFileLoadHook">Class File Load Hook</eventlink>
7389 will be sent (if enabled), but no other <jvmti/> events will be sent.
7390 <p/>
7391 The redefinition may change method bodies, the constant pool and attributes.
7392 The redefinition must not add, remove or rename fields or methods, change the
7393 signatures of methods, change modifiers, or change inheritance.
7394 These restrictions may be lifted in future versions.
7395 See the error return description below for information on error codes
7396 returned if an unsupported redefinition is attempted.
7397 The class file bytes are not verified or installed until they have passed
7398 through the chain of <eventlink id="ClassFileLoadHook"/> events, thus the
7399 returned error code reflects the result of the transformations applied
7400 to the bytes passed into <paramlink id="class_definitions"/>.
7401 If any error code is returned other than <code>JVMTI_ERROR_NONE</code>,
7402 none of the classes to be redefined will have a new definition installed.
7403 When this function returns (with the error code of <code>JVMTI_ERROR_NONE</code>)
7404 all of the classes to be redefined will have their new definitions installed.
7405 </description>
7406 <origin>jvmdi</origin>
7407 <capabilities>
7408 <required id="can_redefine_classes"></required>
7409 <capability id="can_redefine_any_class"></capability>
7410 </capabilities>
7411 <parameters>
7412 <param id="class_count">
7413 <jint min="0"/>
7414 <description>
7415 The number of classes specified in <code>class_definitions</code>
7416 </description>
7417 </param>
7418 <param id="class_definitions">
7419 <inbuf incount="class_count"><struct>jvmtiClassDefinition</struct></inbuf>
7420 <description>
7421 The array of new class definitions
7422 </description>
7423 </param>
7424 </parameters>
7425 <errors>
7426 <error id="JVMTI_ERROR_NULL_POINTER">
7427 One of <code>class_bytes</code> is <code>NULL</code>.
7428 </error>
7429 <error id="JVMTI_ERROR_UNMODIFIABLE_CLASS">
7430 An element of <code>class_definitions</code> cannot be modified.
7431 See <functionlink id="IsModifiableClass"/>.
7432 </error>
7433 <error id="JVMTI_ERROR_INVALID_CLASS">
7434 An element of <code>class_definitions</code> is not a valid class.
7435 </error>
7436 <error id="JVMTI_ERROR_UNSUPPORTED_VERSION">
7437 A new class file has a version number not supported by this VM.
7438 </error>
7439 <error id="JVMTI_ERROR_INVALID_CLASS_FORMAT">
7440 A new class file is malformed (The VM would return a <code>ClassFormatError</code>).
7441 </error>
7442 <error id="JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION">
7443 The new class file definitions would lead to a circular definition
7444 (the VM would return a <code>ClassCircularityError</code>).
7445 </error>
7446 <error id="JVMTI_ERROR_FAILS_VERIFICATION">
7447 The class bytes fail verification.
7448 </error>
7449 <error id="JVMTI_ERROR_NAMES_DONT_MATCH">
7450 The class name defined in a new class file is
7451 different from the name in the old class object.
7452 </error>
7453 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED">
7454 A new class file would require adding a method.
7455 </error>
7456 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED">
7457 A new class version changes a field.
7458 </error>
7459 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED">
7460 A direct superclass is different for a new class
7461 version, or the set of directly implemented
7462 interfaces is different.
7463 </error>
7464 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED">
7465 A new class version does not declare a method
7466 declared in the old class version.
7467 </error>
7468 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED">
7469 A new class version has different modifiers.
7470 </error>
7471 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED">
7472 A method in the new class version has different modifiers
7473 than its counterpart in the old class version.
7474 </error>
7475 </errors>
7476 </function>
7477
7478 </category>
7479
7480 <category id="object" label="Object">
7481
7482 <function id="GetObjectSize" jkernel="yes" phase="start" num="154">
7483 <synopsis>Get Object Size</synopsis>
7484 <description>
7485 For the object indicated by <code>object</code>,
7486 return via <code>size_ptr</code> the size of the object.
7487 This size is an implementation-specific approximation of
7488 the amount of storage consumed by this object.
7489 It may include some or all of the object's overhead, and thus
7490 is useful for comparison within an implementation but not
7491 between implementations.
7492 The estimate may change during a single invocation of the JVM.
7493 </description>
7494 <origin>new</origin>
7495 <capabilities>
7496 </capabilities>
7497 <parameters>
7498 <param id="object">
7499 <jobject/>
7500 <description>
7501 The object to query.
7502 </description>
7503 </param>
7504 <param id="size_ptr">
7505 <outptr><jlong/></outptr>
7506 <description>
7507 On return, points to the object's size in bytes.
7508 </description>
7509 </param>
7510 </parameters>
7511 <errors>
7512 </errors>
7513 </function>
7514
7515 <function id="GetObjectHashCode" phase="start" num="58">
7516 <synopsis>Get Object Hash Code</synopsis>
7517 <description>
7518 For the object indicated by <code>object</code>,
7519 return via <code>hash_code_ptr</code> a hash code.
7520 This hash code could be used to maintain a hash table of object references,
7521 however, on some implementations this can cause significant performance
7522 impacts--in most cases
7523 <internallink id="Heap">tags</internallink>
7524 will be a more efficient means of associating information with objects.
7525 This function guarantees
7526 the same hash code value for a particular object throughout its life
7527 </description>
7528 <origin>jvmdi</origin>
7529 <capabilities>
7530 </capabilities>
7531 <parameters>
7532 <param id="object">
7533 <jobject/>
7534 <description>
7535 The object to query.
7536 </description>
7537 </param>
7538 <param id="hash_code_ptr">
7539 <outptr><jint/></outptr>
7540 <description>
7541 On return, points to the object's hash code.
7542 </description>
7543 </param>
7544 </parameters>
7545 <errors>
7546 </errors>
7547 </function>
7548
7549 <function id="GetObjectMonitorUsage" num="59">
7550 <synopsis>Get Object Monitor Usage</synopsis>
7551 <typedef id="jvmtiMonitorUsage" label="Object monitor usage information">
7552 <field id="owner">
7553 <jthread/>
7554 <description>
7555 The thread owning this monitor, or <code>NULL</code> if unused
7556 </description>
7557 </field>
7558 <field id="entry_count">
7559 <jint/>
7560 <description>
7561 The number of times the owning thread has entered the monitor
7562 </description>
7563 </field>
7564 <field id="waiter_count">
7565 <jint/>
7566 <description>
7567 The number of threads waiting to own this monitor
7568 </description>
7569 </field>
7570 <field id="waiters">
7571 <allocfieldbuf><jthread/></allocfieldbuf>
7572 <description>
7573 The <code>waiter_count</code> waiting threads
7574 </description>
7575 </field>
7576 <field id="notify_waiter_count">
7577 <jint/>
7578 <description>
7579 The number of threads waiting to be notified by this monitor
7580 </description>
7581 </field>
7582 <field id="notify_waiters">
7583 <allocfieldbuf><jthread/></allocfieldbuf>
7584 <description>
7585 The <code>notify_waiter_count</code> threads waiting to be notified
7586 </description>
7587 </field>
7588 </typedef>
7589 <description>
7590 Get information about the object's monitor.
7591 The fields of the <functionlink id="jvmtiMonitorUsage"></functionlink> structure
7592 are filled in with information about usage of the monitor.
7593 <todo>
7594 Decide and then clarify suspend requirements.
7595 </todo>
7596 </description>
7597 <origin>jvmdi</origin>
7598 <capabilities>
7599 <required id="can_get_monitor_info"></required>
7600 </capabilities>
7601 <parameters>
7602 <param id="object">
7603 <jobject/>
7604 <description>
7605 The object to query.
7606 </description>
7607 </param>
7608 <param id="info_ptr">
7609 <outptr><struct>jvmtiMonitorUsage</struct></outptr>
7610 <description>
7611 On return, filled with monitor information for the
7612 specified object.
7613 </description>
7614 </param>
7615 </parameters>
7616 <errors>
7617 </errors>
7618 </function>
7619
7620 <elide>
7621 <function id="GetObjectMonitors" num="116">
7622 <synopsis>Get Object Monitors</synopsis>
7623 <description>
7624 Return the list of object monitors.
7625 <p/>
7626 Note: details about each monitor can be examined with
7627 <functionlink id="GetObjectMonitorUsage"></functionlink>.
7628 </description>
7629 <origin>new</origin>
7630 <capabilities>
7631 <required id="can_get_monitor_info"></required>
7632 </capabilities>
7633 <parameters>
7634 <param id="monitorCnt">
7635 <outptr><jint/></outptr>
7636 <description>
7637 On return, pointer to the number
7638 of monitors returned in <code>monitors_ptr</code>.
7639 </description>
7640 </param>
7641 <param id="monitors_ptr">
7642 <allocbuf outcount="monitorCnt"><jobject/></allocbuf>
7643 <description>
7644 On return, pointer to the monitor list.
7645 </description>
7646 </param>
7647 </parameters>
7648 <errors>
7649 </errors>
7650 </function>
7651 </elide>
7652
7653 </category>
7654
7655 <category id="fieldCategory" label="Field">
7656
7657 <intro>
7658 </intro>
7659
7660 <function id="GetFieldName" phase="start" num="60">
7661 <synopsis>Get Field Name (and Signature)</synopsis>
7662 <description>
7663 For the field indicated by <paramlink id="klass"/> and <paramlink id="field"/>,
7664 return the field name via <paramlink id="name_ptr"/> and field signature via
7665 <paramlink id="signature_ptr"/>.
7666 <p/>
7667 Field signatures are defined in the JNI Specification and
7668 are referred to as <code>field descriptors</code> in
7669 <vmspec chapter="4.3.2"/>.
7670 </description>
7671 <origin>jvmdiClone</origin>
7672 <capabilities>
7673 </capabilities>
7674 <parameters>
7675 <param id="klass">
7676 <jclass field="field"/>
7677 <description>
7678 The class of the field to query.
7679 </description>
7680 </param>
7681 <param id="field">
7682 <jfieldID class="klass"/>
7683 <description>
7684 The field to query.
7685 </description>
7686 </param>
7687 <param id="name_ptr">
7688 <allocbuf>
7689 <char/>
7690 <nullok>the name is not returned</nullok>
7691 </allocbuf>
7692 <description>
7693 On return, points to the field name, encoded as a
7694 <internallink id="mUTF">modified UTF-8</internallink> string.
7695 </description>
7696 </param>
7697 <param id="signature_ptr">
7698 <allocbuf>
7699 <char/>
7700 <nullok>the signature is not returned</nullok>
7701 </allocbuf>
7702 <description>
7703 On return, points to the field signature, encoded as a
7704 <internallink id="mUTF">modified UTF-8</internallink> string.
7705 </description>
7706 </param>
7707 <param id="generic_ptr">
7708 <allocbuf>
7709 <char/>
7710 <nullok>the generic signature is not returned</nullok>
7711 </allocbuf>
7712 <description>
7713 On return, points to the generic signature of the field, encoded as a
7714 <internallink id="mUTF">modified UTF-8</internallink> string.
7715 If there is no generic signature attribute for the field, then,
7716 on return, points to <code>NULL</code>.
7717 </description>
7718 </param>
7719 </parameters>
7720 <errors>
7721 </errors>
7722 </function>
7723
7724 <function id="GetFieldDeclaringClass" phase="start" num="61">
7725 <synopsis>Get Field Declaring Class</synopsis>
7726 <description>
7727 For the field indicated by <code>klass</code> and <code>field</code>
7728 return the class that defined it via <code>declaring_class_ptr</code>.
7729 The declaring class will either be <code>klass</code>, a superclass, or
7730 an implemented interface.
7731 </description>
7732 <origin>jvmdi</origin>
7733 <capabilities>
7734 </capabilities>
7735 <parameters>
7736 <param id="klass">
7737 <jclass field="field"/>
7738 <description>
7739 The class to query.
7740 </description>
7741 </param>
7742 <param id="field">
7743 <jfieldID class="klass"/>
7744 <description>
7745 The field to query.
7746 </description>
7747 </param>
7748 <param id="declaring_class_ptr">
7749 <outptr><jclass/></outptr>
7750 <description>
7751 On return, points to the declaring class
7752 </description>
7753 </param>
7754 </parameters>
7755 <errors>
7756 </errors>
7757 </function>
7758
7759 <function id="GetFieldModifiers" phase="start" num="62">
7760 <synopsis>Get Field Modifiers</synopsis>
7761 <description>
7762 For the field indicated by <code>klass</code> and <code>field</code>
7763 return the access flags via <code>modifiers_ptr</code>.
7764 Access flags are defined in <vmspec chapter="4"/>.
7765 </description>
7766 <origin>jvmdi</origin>
7767 <capabilities>
7768 </capabilities>
7769 <parameters>
7770 <param id="klass">
7771 <jclass field="field"/>
7772 <description>
7773 The class to query.
7774 </description>
7775 </param>
7776 <param id="field">
7777 <jfieldID class="klass"/>
7778 <description>
7779 The field to query.
7780 </description>
7781 </param>
7782 <param id="modifiers_ptr">
7783 <outptr><jint/></outptr>
7784 <description>
7785 On return, points to the access flags.
7786 </description>
7787 </param>
7788 </parameters>
7789 <errors>
7790 </errors>
7791 </function>
7792
7793 <function id="IsFieldSynthetic" phase="start" num="63">
7794 <synopsis>Is Field Synthetic</synopsis>
7795 <description>
7796 For the field indicated by <code>klass</code> and <code>field</code>, return a
7797 value indicating whether the field is synthetic via <code>is_synthetic_ptr</code>.
7798 Synthetic fields are generated by the compiler but not present in the
7799 original source code.
7800 </description>
7801 <origin>jvmdi</origin>
7802 <capabilities>
7803 <required id="can_get_synthetic_attribute"></required>
7804 </capabilities>
7805 <parameters>
7806 <param id="klass">
7807 <jclass field="field"/>
7808 <description>
7809 The class of the field to query.
7810 </description>
7811 </param>
7812 <param id="field">
7813 <jfieldID class="klass"/>
7814 <description>
7815 The field to query.
7816 </description>
7817 </param>
7818 <param id="is_synthetic_ptr">
7819 <outptr><jboolean/></outptr>
7820 <description>
7821 On return, points to the boolean result of this function.
7822 </description>
7823 </param>
7824 </parameters>
7825 <errors>
7826 </errors>
7827 </function>
7828
7829 </category>
7830
7831 <category id="method" label="Method">
7832
7833 <intro>
7834 These functions provide information about a method (represented as a
7835 <typelink id="jmethodID"/>) and set how methods are processed.
7836 </intro>
7837
7838 <intro id="obsoleteMethods" label="Obsolete Methods">
7839 The functions <functionlink id="RetransformClasses"/> and
7840 <functionlink id="RedefineClasses"/> can cause new versions
7841 of methods to be installed.
7842 An original version of a method is considered equivalent
7843 to the new version if:
7844 <ul>
7845 <li>their bytecodes are the same except for indices into the
7846 constant pool and </li>
7847 <li>the referenced constants are equal.</li>
7848 </ul>
7849 An original method version which is not equivalent to the
7850 new method version is called obsolete and is assigned a new method ID;
7851 the original method ID now refers to the new method version.
7852 A method ID can be tested for obsolescence with
7853 <functionlink id="IsMethodObsolete"/>.
7854 </intro>
7855
7856 <function id="GetMethodName" phase="start" num="64">
7857 <synopsis>Get Method Name (and Signature)</synopsis>
7858 <description>
7859 For the method indicated by <code>method</code>,
7860 return the method name via <code>name_ptr</code> and method signature via
7861 <code>signature_ptr</code>.
7862 <p/>
7863 Method signatures are defined in the JNI Specification and are
7864 referred to as <code>method descriptors</code> in
7865 <vmspec chapter="4.3.3"/>.
7866 Note this is different
7867 than method signatures as defined in the <i>Java Language Specification</i>.
7868 </description>
7869 <origin>jvmdiClone</origin>
7870 <capabilities>
7871 </capabilities>
7872 <parameters>
7873 <param id="method">
7874 <jmethodID/>
7875 <description>
7876 The method to query.
7877 </description>
7878 </param>
7879 <param id="name_ptr">
7880 <allocbuf>
7881 <char/>
7882 <nullok>the name is not returned</nullok>
7883 </allocbuf>
7884 <description>
7885 On return, points to the method name, encoded as a
7886 <internallink id="mUTF">modified UTF-8</internallink> string.
7887 </description>
7888 </param>
7889 <param id="signature_ptr">
7890 <allocbuf>
7891 <char/>
7892 <nullok>the signature is not returned</nullok>
7893 </allocbuf>
7894 <description>
7895 On return, points to the method signature, encoded as a
7896 <internallink id="mUTF">modified UTF-8</internallink> string.
7897 </description>
7898 </param>
7899 <param id="generic_ptr">
7900 <allocbuf>
7901 <char/>
7902 <nullok>the generic signature is not returned</nullok>
7903 </allocbuf>
7904 <description>
7905 On return, points to the generic signature of the method, encoded as a
7906 <internallink id="mUTF">modified UTF-8</internallink> string.
7907 If there is no generic signature attribute for the method, then,
7908 on return, points to <code>NULL</code>.
7909 </description>
7910 </param>
7911 </parameters>
7912 <errors>
7913 </errors>
7914 </function>
7915
7916 <function id="GetMethodDeclaringClass" phase="start" num="65">
7917 <synopsis>Get Method Declaring Class</synopsis>
7918 <description>
7919 For the method indicated by <code>method</code>,
7920 return the class that defined it via <code>declaring_class_ptr</code>.
7921 </description>
7922 <origin>jvmdi</origin>
7923 <capabilities>
7924 </capabilities>
7925 <parameters>
7926 <param id="klass">
7927 <jclass method="method"/>
7928 <description>
7929 The class to query.
7930 </description>
7931 </param>
7932 <param id="method">
7933 <jmethodID class="klass"/>
7934 <description>
7935 The method to query.
7936 </description>
7937 </param>
7938 <param id="declaring_class_ptr">
7939 <outptr><jclass/></outptr>
7940 <description>
7941 On return, points to the declaring class
7942 </description>
7943 </param>
7944 </parameters>
7945 <errors>
7946 </errors>
7947 </function>
7948
7949 <function id="GetMethodModifiers" phase="start" num="66">
7950 <synopsis>Get Method Modifiers</synopsis>
7951 <description>
7952 For the method indicated by <code>method</code>,
7953 return the access flags via <code>modifiers_ptr</code>.
7954 Access flags are defined in <vmspec chapter="4"/>.
7955 </description>
7956 <origin>jvmdi</origin>
7957 <capabilities>
7958 </capabilities>
7959 <parameters>
7960 <param id="klass">
7961 <jclass method="method"/>
7962 <description>
7963 The class to query.
7964 </description>
7965 </param>
7966 <param id="method">
7967 <jmethodID class="klass"/>
7968 <description>
7969 The method to query.
7970 </description>
7971 </param>
7972 <param id="modifiers_ptr">
7973 <outptr><jint/></outptr>
7974 <description>
7975 On return, points to the access flags.
7976 </description>
7977 </param>
7978 </parameters>
7979 <errors>
7980 </errors>
7981 </function>
7982
7983 <function id="GetMaxLocals" phase="start" num="68">
7984 <synopsis>Get Max Locals</synopsis>
7985 <description>
7986 For the method indicated by <code>method</code>,
7987 return the number of local variable slots used by the method,
7988 including the local variables used to pass parameters to the
7989 method on its invocation.
7990 <p/>
7991 See <code>max_locals</code> in <vmspec chapter="4.7.3"/>.
7992 </description>
7993 <origin>jvmdi</origin>
7994 <capabilities>
7995 </capabilities>
7996 <parameters>
7997 <param id="klass">
7998 <jclass method="method"/>
7999 <description>
8000 The class to query.
8001 </description>
8002 </param>
8003 <param id="method">
8004 <jmethodID class="klass" native="error"/>
8005 <description>
8006 The method to query.
8007 </description>
8008 </param>
8009 <param id="max_ptr">
8010 <outptr><jint/></outptr>
8011 <description>
8012 On return, points to the maximum number of local slots
8013 </description>
8014 </param>
8015 </parameters>
8016 <errors>
8017 </errors>
8018 </function>
8019
8020 <function id="GetArgumentsSize" phase="start" num="69">
8021 <synopsis>Get Arguments Size</synopsis>
8022 <description>
8023 For the method indicated by <code>method</code>,
8024 return via <code>max_ptr</code> the number of local variable slots used
8025 by the method's arguments.
8026 Note that two-word arguments use two slots.
8027 </description>
8028 <origin>jvmdi</origin>
8029 <capabilities>
8030 </capabilities>
8031 <parameters>
8032 <param id="klass">
8033 <jclass method="method"/>
8034 <description>
8035 The class to query.
8036 </description>
8037 </param>
8038 <param id="method">
8039 <jmethodID class="klass" native="error"/>
8040 <description>
8041 The method to query.
8042 </description>
8043 </param>
8044 <param id="size_ptr">
8045 <outptr><jint/></outptr>
8046 <description>
8047 On return, points to the number of argument slots
8048 </description>
8049 </param>
8050 </parameters>
8051 <errors>
8052 </errors>
8053 </function>
8054
8055 <function id="GetLineNumberTable" phase="start" num="70">
8056 <synopsis>Get Line Number Table</synopsis>
8057 <typedef id="jvmtiLineNumberEntry" label="Line number table entry">
8058 <field id="start_location">
8059 <jlocation/>
8060 <description>
8061 the <datalink id="jlocation"></datalink> where the line begins
8062 </description>
8063 </field>
8064 <field id="line_number">
8065 <jint/>
8066 <description>
8067 the line number
8068 </description>
8069 </field>
8070 </typedef>
8071 <description>
8072 For the method indicated by <code>method</code>,
8073 return a table of source line number entries. The size of the table is
8074 returned via <code>entry_count_ptr</code> and the table itself is
8075 returned via <code>table_ptr</code>.
8076 </description>
8077 <origin>jvmdi</origin>
8078 <capabilities>
8079 <required id="can_get_line_numbers"></required>
8080 </capabilities>
8081 <parameters>
8082 <param id="klass">
8083 <jclass method="method"/>
8084 <description>
8085 The class to query.
8086 </description>
8087 </param>
8088 <param id="method">
8089 <jmethodID class="klass" native="error"/>
8090 <description>
8091 The method to query.
8092 </description>
8093 </param>
8094 <param id="entry_count_ptr">
8095 <outptr><jint/></outptr>
8096 <description>
8097 On return, points to the number of entries in the table
8098 </description>
8099 </param>
8100 <param id="table_ptr">
8101 <allocbuf outcount="entry_count_ptr"><struct>jvmtiLineNumberEntry</struct></allocbuf>
8102 <description>
8103 On return, points to the line number table pointer.
8104 </description>
8105 </param>
8106 </parameters>
8107 <errors>
8108 <error id="JVMTI_ERROR_ABSENT_INFORMATION">
8109 Class information does not include line numbers.
8110 </error>
8111 </errors>
8112 </function>
8113
8114 <function id="GetMethodLocation" phase="start" num="71">
8115 <synopsis>Get Method Location</synopsis>
8116 <description>
8117 For the method indicated by <code>method</code>,
8118 return the beginning and ending addresses through
8119 <code>start_location_ptr</code> and <code>end_location_ptr</code>. In a
8120 conventional byte code indexing scheme,
8121 <code>start_location_ptr</code> will always point to zero
8122 and <code>end_location_ptr</code>
8123 will always point to the byte code count minus one.
8124 </description>
8125 <origin>jvmdi</origin>
8126 <capabilities>
8127 </capabilities>
8128 <parameters>
8129 <param id="klass">
8130 <jclass method="method"/>
8131 <description>
8132 The class to query.
8133 </description>
8134 </param>
8135 <param id="method">
8136 <jmethodID class="klass" native="error"/>
8137 <description>
8138 The method to query.
8139 </description>
8140 </param>
8141 <param id="start_location_ptr">
8142 <outptr><jlocation/></outptr>
8143 <description>
8144 On return, points to the first location, or
8145 <code>-1</code> if location information is not available.
8146 If the information is available and
8147 <functionlink id="GetJLocationFormat"></functionlink>
8148 returns <datalink id="JVMTI_JLOCATION_JVMBCI"></datalink>
8149 then this will always be zero.
8150 </description>
8151 </param>
8152 <param id="end_location_ptr">
8153 <outptr><jlocation/></outptr>
8154 <description>
8155 On return, points to the last location,
8156 or <code>-1</code> if location information is not available.
8157 </description>
8158 </param>
8159 </parameters>
8160 <errors>
8161 <error id="JVMTI_ERROR_ABSENT_INFORMATION">
8162 Class information does not include method sizes.
8163 </error>
8164 </errors>
8165 </function>
8166
8167 <function id="GetLocalVariableTable" num="72">
8168 <synopsis>Get Local Variable Table</synopsis>
8169 <typedef id="jvmtiLocalVariableEntry" label="Local variable table entry">
8170 <field id="start_location">
8171 <jlocation/>
8172 <description>
8173 The code array index where the local variable is first valid
8174 (that is, where it must have a value).
8175 </description>
8176 </field>
8177 <field id="length">
8178 <jint/>
8179 <description>
8180 The length of the valid section for this local variable.
8181 The last code array index where the local variable is valid
8182 is <code>start_location + length</code>.
8183 </description>
8184 </field>
8185 <field id="name">
8186 <allocfieldbuf><char/></allocfieldbuf>
8187 <description>
8188 The local variable name, encoded as a
8189 <internallink id="mUTF">modified UTF-8</internallink> string.
8190 </description>
8191 </field>
8192 <field id="signature">
8193 <allocfieldbuf><char/></allocfieldbuf>
8194 <description>
8195 The local variable's type signature, encoded as a
8196 <internallink id="mUTF">modified UTF-8</internallink> string.
8197 The signature format is the same as that defined in
8198 <vmspec chapter="4.3.2"/>.
8199 </description>
8200 </field>
8201 <field id="generic_signature">
8202 <allocfieldbuf><char/></allocfieldbuf>
8203 <description>
8204 The local variable's generic signature, encoded as a
8205 <internallink id="mUTF">modified UTF-8</internallink> string.
8206 The value of this field will be <code>NULL</code> for any local
8207 variable which does not have a generic type.
8208 </description>
8209 </field>
8210 <field id="slot">
8211 <jint/>
8212 <description>
8213 The local variable's slot. See <internallink id="local">Local Variables</internallink>.
8214 </description>
8215 </field>
8216 </typedef>
8217 <description>
8218 Return local variable information.
8219 </description>
8220 <origin>jvmdiClone</origin>
8221 <capabilities>
8222 <required id="can_access_local_variables"></required>
8223 </capabilities>
8224 <parameters>
8225 <param id="method">
8226 <jmethodID native="error"/>
8227 <description>
8228 The method to query.
8229 </description>
8230 </param>
8231 <param id="entry_count_ptr">
8232 <outptr><jint/></outptr>
8233 <description>
8234 On return, points to the number of entries in the table
8235 </description>
8236 </param>
8237 <param id="table_ptr">
8238 <allocbuf outcount="entry_count_ptr"><struct>jvmtiLocalVariableEntry</struct></allocbuf>
8239 <description>
8240 On return, points to an array of local variable table entries.
8241 </description>
8242 </param>
8243 </parameters>
8244 <errors>
8245 <error id="JVMTI_ERROR_ABSENT_INFORMATION">
8246 Class information does not include local variable
8247 information.
8248 </error>
8249 </errors>
8250 </function>
8251
8252 <function id="GetBytecodes" phase="start" num="75">
8253 <synopsis>Get Bytecodes</synopsis>
8254 <description>
8255 For the method indicated by <code>method</code>,
8256 return the byte codes that implement the method. The number of
8257 bytecodes is returned via <code>bytecode_count_ptr</code>. The byte codes
8258 themselves are returned via <code>bytecodes_ptr</code>.
8259 </description>
8260 <origin>jvmdi</origin>
8261 <capabilities>
8262 <required id="can_get_bytecodes"></required>
8263 </capabilities>
8264 <parameters>
8265 <param id="klass">
8266 <jclass method="method"/>
8267 <description>
8268 The class to query.
8269 </description>
8270 </param>
8271 <param id="method">
8272 <jmethodID class="klass" native="error"/>
8273 <description>
8274 The method to query.
8275 </description>
8276 </param>
8277 <param id="bytecode_count_ptr">
8278 <outptr><jint/></outptr>
8279 <description>
8280 On return, points to the length of the byte code array
8281 </description>
8282 </param>
8283 <param id="bytecodes_ptr">
8284 <allocbuf outcount="bytecode_count_ptr"><uchar/></allocbuf>
8285 <description>
8286 On return, points to the pointer to the byte code array
8287 </description>
8288 </param>
8289 </parameters>
8290 <errors>
8291 </errors>
8292 </function>
8293
8294 <function id="IsMethodNative" phase="start" num="76">
8295 <synopsis>Is Method Native</synopsis>
8296 <description>
8297 For the method indicated by <code>method</code>, return a
8298 value indicating whether the method is native via <code>is_native_ptr</code>
8299 </description>
8300 <origin>jvmdi</origin>
8301 <capabilities>
8302 </capabilities>
8303 <parameters>
8304 <param id="klass">
8305 <jclass method="method"/>
8306 <description>
8307 The class to query.
8308 </description>
8309 </param>
8310 <param id="method">
8311 <jmethodID class="klass"/>
8312 <description>
8313 The method to query.
8314 </description>
8315 </param>
8316 <param id="is_native_ptr">
8317 <outptr><jboolean/></outptr>
8318 <description>
8319 On return, points to the boolean result of this function.
8320 </description>
8321 </param>
8322 </parameters>
8323 <errors>
8324 </errors>
8325 </function>
8326
8327 <function id="IsMethodSynthetic" phase="start" num="77">
8328 <synopsis>Is Method Synthetic</synopsis>
8329 <description>
8330 For the method indicated by <code>method</code>, return a
8331 value indicating whether the method is synthetic via <code>is_synthetic_ptr</code>.
8332 Synthetic methods are generated by the compiler but not present in the
8333 original source code.
8334 </description>
8335 <origin>jvmdi</origin>
8336 <capabilities>
8337 <required id="can_get_synthetic_attribute"></required>
8338 </capabilities>
8339 <parameters>
8340 <param id="klass">
8341 <jclass method="method"/>
8342 <description>
8343 The class to query.
8344 </description>
8345 </param>
8346 <param id="method">
8347 <jmethodID class="klass"/>
8348 <description>
8349 The method to query.
8350 </description>
8351 </param>
8352 <param id="is_synthetic_ptr">
8353 <outptr><jboolean/></outptr>
8354 <description>
8355 On return, points to the boolean result of this function.
8356 </description>
8357 </param>
8358 </parameters>
8359 <errors>
8360 </errors>
8361 </function>
8362
8363 <function id="IsMethodObsolete" phase="start" num="91">
8364 <synopsis>Is Method Obsolete</synopsis>
8365 <description>
8366 Determine if a method ID refers to an
8367 <internallink id="obsoleteMethods">obsolete</internallink>
8368 method version.
8369 </description>
8370 <origin>jvmdi</origin>
8371 <capabilities>
8372 </capabilities>
8373 <parameters>
8374 <param id="klass">
8375 <jclass method="method"/>
8376 <description>
8377 The class to query.
8378 </description>
8379 </param>
8380 <param id="method">
8381 <jmethodID class="klass"/>
8382 <description>
8383 The method ID to query.
8384 </description>
8385 </param>
8386 <param id="is_obsolete_ptr">
8387 <outptr><jboolean/></outptr>
8388 <description>
8389 On return, points to the boolean result of this function.
8390 </description>
8391 </param>
8392 </parameters>
8393 <errors>
8394 </errors>
8395 </function>
8396
8397 <function id="SetNativeMethodPrefix" jkernel="yes" phase="any" num="73" since="1.1">
8398 <synopsis>Set Native Method Prefix</synopsis>
8399 <description>
8400 This function modifies the failure handling of
8401 native method resolution by allowing retry
8402 with a prefix applied to the name.
8403 When used with the
8404 <eventlink id="ClassFileLoadHook">ClassFileLoadHook
8405 event</eventlink>, it enables native methods to be
8406 <internallink id="bci">instrumented</internallink>.
8407 <p/>
8408 Since native methods cannot be directly instrumented
8409 (they have no bytecodes), they must be wrapped with
8410 a non-native method which can be instrumented.
8411 For example, if we had:
8412 <example>
8413 native boolean foo(int x);</example>
8414 <p/>
8415 We could transform the class file (with the
8416 ClassFileLoadHook event) so that this becomes:
8417 <example>
8418 boolean foo(int x) {
8419 <i>... record entry to foo ...</i>
8420 return wrapped_foo(x);
8421 }
8422
8423 native boolean wrapped_foo(int x);</example>
8424 <p/>
8425 Where foo becomes a wrapper for the actual native method
8426 with the appended prefix "wrapped_". Note that
8427 "wrapped_" would be a poor choice of prefix since it
8428 might conceivably form the name of an existing method
8429 thus something like "$$$MyAgentWrapped$$$_" would be
8430 better but would make these examples less readable.
8431 <p/>
8432 The wrapper will allow data to be collected on the native
8433 method call, but now the problem becomes linking up the
8434 wrapped method with the native implementation.
8435 That is, the method <code>wrapped_foo</code> needs to be
8436 resolved to the native implementation of <code>foo</code>,
8437 which might be:
8438 <example>
8439 Java_somePackage_someClass_foo(JNIEnv* env, jint x)</example>
8440 <p/>
8441 This function allows the prefix to be specified and the
8442 proper resolution to occur.
8443 Specifically, when the standard resolution fails, the
8444 resolution is retried taking the prefix into consideration.
8445 There are two ways that resolution occurs, explicit
8446 resolution with the JNI function <code>RegisterNatives</code>
8447 and the normal automatic resolution. For
8448 <code>RegisterNatives</code>, the VM will attempt this
8449 association:
8450 <example>
8451 method(foo) -> nativeImplementation(foo)</example>
8452 <p/>
8453 When this fails, the resolution will be retried with
8454 the specified prefix prepended to the method name,
8455 yielding the correct resolution:
8456 <example>
8457 method(wrapped_foo) -> nativeImplementation(foo)</example>
8458 <p/>
8459 For automatic resolution, the VM will attempt:
8460 <example>
8461 method(wrapped_foo) -> nativeImplementation(wrapped_foo)</example>
8462 <p/>
8463 When this fails, the resolution will be retried with
8464 the specified prefix deleted from the implementation name,
8465 yielding the correct resolution:
8466 <example>
8467 method(wrapped_foo) -> nativeImplementation(foo)</example>
8468 <p/>
8469 Note that since the prefix is only used when standard
8470 resolution fails, native methods can be wrapped selectively.
8471 <p/>
8472 Since each <jvmti/> environment is independent and
8473 can do its own transformation of the bytecodes, more
8474 than one layer of wrappers may be applied. Thus each
8475 environment needs its own prefix. Since transformations
8476 are applied in order, the prefixes, if applied, will
8477 be applied in the same order.
8478 The order of transformation application is described in
8479 the <eventlink id="ClassFileLoadHook"/> event.
8480 Thus if three environments applied
8481 wrappers, <code>foo</code> might become
8482 <code>$env3_$env2_$env1_foo</code>. But if, say,
8483 the second environment did not apply a wrapper to
8484 <code>foo</code> it would be just
8485 <code>$env3_$env1_foo</code>. To be able to
8486 efficiently determine the sequence of prefixes,
8487 an intermediate prefix is only applied if its non-native
8488 wrapper exists. Thus, in the last example, even though
8489 <code>$env1_foo</code> is not a native method, the
8490 <code>$env1_</code> prefix is applied since
8491 <code>$env1_foo</code> exists.
8492 <p/>
8493 Since the prefixes are used at resolution time
8494 and since resolution may be arbitrarily delayed, a
8495 native method prefix must remain set as long as there
8496 are corresponding prefixed native methods.
8497 </description>
8498 <origin>new</origin>
8499 <capabilities>
8500 <required id="can_set_native_method_prefix"></required>
8501 </capabilities>
8502 <parameters>
8503 <param id="prefix">
8504 <inbuf>
8505 <char/>
8506 <nullok>
8507 any existing prefix in this environment is cancelled
8508 </nullok>
8509 </inbuf>
8510 <description>
8511 The prefix to apply, encoded as a
8512 <internallink id="mUTF">modified UTF-8</internallink> string.
8513 </description>
8514 </param>
8515 </parameters>
8516 <errors>
8517 </errors>
8518 </function>
8519
8520 <function id="SetNativeMethodPrefixes" jkernel="yes" phase="any" num="74" since="1.1">
8521 <synopsis>Set Native Method Prefixes</synopsis>
8522 <description>
8523 For a normal agent, <functionlink id="SetNativeMethodPrefix"/>
8524 will provide all needed native method prefixing.
8525 For a meta-agent that performs multiple independent class
8526 file transformations (for example as a proxy for another
8527 layer of agents) this function allows each transformation
8528 to have its own prefix.
8529 The prefixes are applied in the order supplied and are
8530 processed in the same manor as described for the
8531 application of prefixes from multiple <jvmti/> environments
8532 in <functionlink id="SetNativeMethodPrefix"/>.
8533 <p/>
8534 Any previous prefixes are replaced. Thus, calling this
8535 function with a <paramlink id="prefix_count"/> of <code>0</code>
8536 disables prefixing in this environment.
8537 <p/>
8538 <functionlink id="SetNativeMethodPrefix"/> and this function
8539 are the two ways to set the prefixes.
8540 Calling <code>SetNativeMethodPrefix</code> with
8541 a prefix is the same as calling this function with
8542 <paramlink id="prefix_count"/> of <code>1</code>.
8543 Calling <code>SetNativeMethodPrefix</code> with
8544 <code>NULL</code> is the same as calling this function with
8545 <paramlink id="prefix_count"/> of <code>0</code>.
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_count">
8553 <jint min="0"/>
8554 <description>
8555 The number of prefixes to apply.
8556 </description>
8557 </param>
8558 <param id="prefixes">
8559 <agentbuf>
8560 <char/>
8561 </agentbuf>
8562 <description>
8563 The prefixes to apply for this environment, each encoded as a
8564 <internallink id="mUTF">modified UTF-8</internallink> string.
8565 </description>
8566 </param>
8567 </parameters>
8568 <errors>
8569 </errors>
8570 </function>
8571
8572 </category>
8573
8574 <category id="RawMonitors" label="Raw Monitor">
8575
8576 <function id="CreateRawMonitor" phase="onload" callbacksafe="safe" num="31">
8577 <synopsis>Create Raw Monitor</synopsis>
8578 <description>
8579 Create a raw monitor.
8580 </description>
8581 <origin>jvmdi</origin>
8582 <capabilities>
8583 </capabilities>
8584 <parameters>
8585 <param id="name">
8586 <inbuf><char/></inbuf>
8587 <description>
8588 A name to identify the monitor, encoded as a
8589 <internallink id="mUTF">modified UTF-8</internallink> string.
8590 </description>
8591 </param>
8592 <param id="monitor_ptr">
8593 <outptr><jrawMonitorID/></outptr>
8594 <description>
8595 On return, points to the created monitor.
8596 </description>
8597 </param>
8598 </parameters>
8599 <errors>
8600 </errors>
8601 </function>
8602
8603 <function id="DestroyRawMonitor" phase="onload" callbacksafe="safe" num="32">
8604 <synopsis>Destroy Raw Monitor</synopsis>
8605 <description>
8606 Destroy the raw monitor.
8607 If the monitor being destroyed has been entered by this thread, it will be
8608 exited before it is destroyed.
8609 If the monitor being destroyed has been entered by another thread,
8610 an error will be returned and the monitor will not be destroyed.
8611 </description>
8612 <origin>jvmdi</origin>
8613 <capabilities>
8614 </capabilities>
8615 <parameters>
8616 <param id="monitor">
8617 <jrawMonitorID/>
8618 <description>
8619 The monitor
8620 </description>
8621 </param>
8622 </parameters>
8623 <errors>
8624 <error id="JVMTI_ERROR_NOT_MONITOR_OWNER">
8625 Not monitor owner
8626 </error>
8627 </errors>
8628 </function>
8629
8630 <function id="RawMonitorEnter" phase="any" callbacksafe="safe" impl="innative notrace" num="33">
8631 <synopsis>Raw Monitor Enter</synopsis>
8632 <description>
8633 Gain exclusive ownership of a raw monitor.
8634 The same thread may enter a monitor more then once.
8635 The thread must
8636 <functionlink id="RawMonitorExit">exit</functionlink>
8637 the monitor the same number of times as it is entered.
8638 If a monitor is entered during <code>OnLoad</code> (before attached threads exist)
8639 and has not exited when attached threads come into existence, the enter
8640 is considered to have occurred on the main thread.
8641 </description>
8642 <origin>jvmdi</origin>
8643 <capabilities>
8644 </capabilities>
8645 <parameters>
8646 <param id="monitor">
8647 <jrawMonitorID/>
8648 <description>
8649 The monitor
8650 </description>
8651 </param>
8652 </parameters>
8653 <errors>
8654 </errors>
8655 </function>
8656
8657 <function id="RawMonitorExit" phase="any" callbacksafe="safe" impl="innative notrace" num="34">
8658 <synopsis>Raw Monitor Exit</synopsis>
8659 <description>
8660 Release exclusive ownership of a raw monitor.
8661 </description>
8662 <origin>jvmdi</origin>
8663 <capabilities>
8664 </capabilities>
8665 <parameters>
8666 <param id="monitor">
8667 <jrawMonitorID/>
8668 <description>
8669 The monitor
8670 </description>
8671 </param>
8672 </parameters>
8673 <errors>
8674 <error id="JVMTI_ERROR_NOT_MONITOR_OWNER">
8675 Not monitor owner
8676 </error>
8677 </errors>
8678 </function>
8679
8680 <function id="RawMonitorWait" phase="any" callbacksafe="safe" impl="innative notrace" num="35">
8681 <synopsis>Raw Monitor Wait</synopsis>
8682 <description>
8683 Wait for notification of the raw monitor.
8684 <p/>
8685 Causes the current thread to wait until either another thread calls
8686 <functionlink id="RawMonitorNotify"/> or
8687 <functionlink id="RawMonitorNotifyAll"/>
8688 for the specified raw monitor, or the specified
8689 <paramlink id="millis">timeout</paramlink>
8690 has elapsed.
8691 </description>
8692 <origin>jvmdi</origin>
8693 <capabilities>
8694 </capabilities>
8695 <parameters>
8696 <param id="monitor">
8697 <jrawMonitorID/>
8698 <description>
8699 The monitor
8700 </description>
8701 </param>
8702 <param id="millis">
8703 <jlong/>
8704 <description>
8705 The timeout, in milliseconds. If the timeout is
8706 zero, then real time is not taken into consideration
8707 and the thread simply waits until notified.
8708 </description>
8709 </param>
8710 </parameters>
8711 <errors>
8712 <error id="JVMTI_ERROR_NOT_MONITOR_OWNER">
8713 Not monitor owner
8714 </error>
8715 <error id="JVMTI_ERROR_INTERRUPT">
8716 Wait was interrupted, try again
8717 </error>
8718 </errors>
8719 </function>
8720
8721 <function id="RawMonitorNotify" phase="any" callbacksafe="safe" impl="notrace" num="36">
8722 <synopsis>Raw Monitor Notify</synopsis>
8723 <description>
8724 Notify a single thread waiting on the raw monitor.
8725 </description>
8726 <origin>jvmdi</origin>
8727 <capabilities>
8728 </capabilities>
8729 <parameters>
8730 <param id="monitor">
8731 <jrawMonitorID/>
8732 <description>
8733 The monitor
8734 </description>
8735 </param>
8736 </parameters>
8737 <errors>
8738 <error id="JVMTI_ERROR_NOT_MONITOR_OWNER">
8739 Not monitor owner
8740 </error>
8741 </errors>
8742 </function>
8743
8744 <function id="RawMonitorNotifyAll" phase="any" callbacksafe="safe" impl="notrace" num="37">
8745 <synopsis>Raw Monitor Notify All</synopsis>
8746 <description>
8747 Notify all threads waiting on the raw monitor.
8748 </description>
8749 <origin>jvmdi</origin>
8750 <capabilities>
8751 </capabilities>
8752 <parameters>
8753 <param id="monitor">
8754 <jrawMonitorID/>
8755 <description>
8756 The monitor
8757 </description>
8758 </param>
8759 </parameters>
8760 <errors>
8761 <error id="JVMTI_ERROR_NOT_MONITOR_OWNER">
8762 Not monitor owner
8763 </error>
8764 </errors>
8765 </function>
8766
8767 <elide>
8768 <function id="GetRawMonitorUse" num="118">
8769 <synopsis>Get Raw Monitor Use</synopsis>
8770 <description>
8771 The fields of the <functionlink id="jvmtiMonitorUsage"></functionlink> structure
8772 are filled in with information about usage of the raw monitor.
8773 </description>
8774 <origin>new</origin>
8775 <capabilities>
8776 <required id="can_get_raw_monitor_usage"></required>
8777 </capabilities>
8778 <parameters>
8779 <param id="monitor">
8780 <jrawMonitorID/>
8781 <description>
8782 the raw monitor to query.
8783 </description>
8784 </param>
8785 <param id="info_ptr">
8786 <outptr><struct>jvmtiMonitorUsage</struct></outptr>
8787 <description>
8788 On return, filled with monitor information for the
8789 specified raw monitor.
8790 </description>
8791 </param>
8792 </parameters>
8793 <errors>
8794 </errors>
8795 </function>
8796
8797 <function id="GetRawMonitors" num="119">
8798 <synopsis>Get Raw Monitors</synopsis>
8799 <description>
8800 Return the list of raw monitors.
8801 <p/>
8802 Note: details about each monitor can be examined with
8803 <functionlink id="GetRawMonitorUse"></functionlink>.
8804 </description>
8805 <origin>new</origin>
8806 <capabilities>
8807 <required id="can_get_raw_monitor_usage"></required>
8808 </capabilities>
8809 <parameters>
8810 <param id="monitorCnt">
8811 <outptr><jint/></outptr>
8812 <description>
8813 On return, pointer to the number
8814 of monitors returned in <code>monitors_ptr</code>.
8815 </description>
8816 </param>
8817 <param id="monitors_ptr">
8818 <allocbuf outcount="monitorCnt"><jrawMonitorID/></allocbuf>
8819 <description>
8820 On return, pointer to the monitor list.
8821 </description>
8822 </param>
8823 </parameters>
8824 <errors>
8825 </errors>
8826 </function>
8827 </elide>
8828 </category>
8829
8830 <category id="jniIntercept" label="JNI Function Interception">
8831
8832 <intro>
8833 Provides the ability to intercept and resend
8834 Java Native Interface (JNI) function calls
8835 by manipulating the JNI function table.
8836 See <externallink id="http://docs.oracle.com/javase/7/docs/technotes/guides/jni/spec/functions.html">JNI
8837 Functions</externallink> in the <i>Java Native Interface Specification</i>.
8838 <p/>
8839 The following example illustrates intercepting the
8840 <code>NewGlobalRef</code> JNI call in order to count reference
8841 creation.
8842 <example>
8843 JNIEnv original_jni_Functions;
8844 JNIEnv redirected_jni_Functions;
8845 int my_global_ref_count = 0;
8846
8847 jobject
8848 MyNewGlobalRef(JNIEnv *jni_env, jobject lobj) {
8849 ++my_global_ref_count;
8850 return originalJNIFunctions->NewGlobalRef(env, lobj);
8851 }
8852
8853 void
8854 myInit() {
8855 jvmtiError err;
8856
8857 err = (*jvmti_env)->GetJNIFunctionTable(jvmti_env, &original_jni_Functions);
8858 if (err != JVMTI_ERROR_NONE) {
8859 die();
8860 }
8861 err = (*jvmti_env)->GetJNIFunctionTable(jvmti_env, &redirected_jni_Functions);
8862 if (err != JVMTI_ERROR_NONE) {
8863 die();
8864 }
8865 redirectedJNIFunctions->NewGlobalRef = MyNewGlobalRef;
8866 err = (*jvmti_env)->SetJNIFunctionTable(jvmti_env, redirected_jni_Functions);
8867 if (err != JVMTI_ERROR_NONE) {
8868 die();
8869 }
8870 }
8871 </example>
8872 Sometime after <code>myInit</code> is called the user's JNI
8873 code is executed which makes the call to create a new global
8874 reference. Instead of going to the normal JNI implementation
8875 the call goes to <code>myNewGlobalRef</code>. Note that a
8876 copy of the original function table is kept so that the normal
8877 JNI function can be called after the data is collected.
8878 Note also that any JNI functions which are not overwritten
8879 will behave normally.
8880 <todo>
8881 check that the example compiles and executes.
8882 </todo>
8883 </intro>
8884
8885 <function id="SetJNIFunctionTable" phase="start" num="120">
8886 <synopsis>Set JNI Function Table</synopsis>
8887 <description>
8888 Set the JNI function table
8889 in all current and future JNI environments.
8890 As a result, all future JNI calls are directed to the specified functions.
8891 Use <functionlink id="GetJNIFunctionTable"></functionlink> to get the
8892 function table to pass to this function.
8893 For this function to take effect the the updated table entries must be
8894 used by the JNI clients.
8895 Since the table is defined <code>const</code> some compilers may optimize
8896 away the access to the table, thus preventing this function from taking
8897 effect.
8898 The table is copied--changes to the local copy of the
8899 table have no effect.
8900 This function affects only the function table, all other aspects of the environment are
8901 unaffected.
8902 See the examples <internallink id="jniIntercept">above</internallink>.
8903 </description>
8904 <origin>new</origin>
8905 <capabilities>
8906 </capabilities>
8907 <parameters>
8908 <param id="function_table">
8909 <inptr>
8910 <struct>jniNativeInterface</struct>
8911 </inptr>
8912 <description>
8913 Points to the new JNI function table.
8914 </description>
8915 </param>
8916 </parameters>
8917 <errors>
8918 </errors>
8919 </function>
8920
8921 <function id="GetJNIFunctionTable" phase="start" num="121">
8922 <synopsis>Get JNI Function Table</synopsis>
8923 <description>
8924 Get the JNI function table.
8925 The JNI function table is copied into allocated memory.
8926 If <functionlink id="SetJNIFunctionTable"></functionlink>
8927 has been called, the modified (not the original) function
8928 table is returned.
8929 Only the function table is copied, no other aspects of the environment
8930 are copied.
8931 See the examples <internallink id="jniIntercept">above</internallink>.
8932 </description>
8933 <origin>new</origin>
8934 <capabilities>
8935 </capabilities>
8936 <parameters>
8937 <param id="function_table">
8938 <allocbuf>
8939 <struct>jniNativeInterface</struct>
8940 </allocbuf>
8941 <description>
8942 On return, <code>*function_table</code>
8943 points a newly allocated copy of the JNI function table.
8944 </description>
8945 </param>
8946 </parameters>
8947 <errors>
8948 </errors>
8949 </function>
8950
8951 </category>
8952
8953 <category id="eventManagement" label="Event Management">
8954
8955 <function id="SetEventCallbacks" jkernel="yes" phase="onload" num="122">
8956 <synopsis>Set Event Callbacks</synopsis>
8957 <description>
8958 Set the functions to be called for each event.
8959 The callbacks are specified by supplying a replacement function table.
8960 The function table is copied--changes to the local copy of the
8961 table have no effect.
8962 This is an atomic action, all callbacks are set at once.
8963 No events are sent before this function is called.
8964 When an entry is <code>NULL</code> or when the event is beyond
8965 <paramlink id="size_of_callbacks"></paramlink> no event is sent.
8966 Details on events are
8967 described <internallink id="EventSection">later</internallink> in this document.
8968 An event must be enabled and have a callback in order to be
8969 sent--the order in which this function and
8970 <functionlink id="SetEventNotificationMode"></functionlink>
8971 are called does not affect the result.
8972 </description>
8973 <origin>new</origin>
8974 <capabilities>
8975 </capabilities>
8976 <parameters>
8977 <param id="callbacks">
8978 <inptr>
8979 <struct>jvmtiEventCallbacks</struct>
8980 <nullok>remove the existing callbacks</nullok>
8981 </inptr>
8982 <description>
8983 The new event callbacks.
8984 </description>
8985 </param>
8986 <param id="size_of_callbacks">
8987 <jint min="0"/>
8988 <description>
8989 <code>sizeof(jvmtiEventCallbacks)</code>--for version
8990 compatibility.
8991 </description>
8992 </param>
8993 </parameters>
8994 <errors>
8995 </errors>
8996 </function>
8997
8998 <function id="SetEventNotificationMode" jkernel="yes" phase="onload" num="2">
8999 <synopsis>Set Event Notification Mode</synopsis>
9000 <description>
9001 Control the generation of events.
9002 <constants id="jvmtiEventMode" label="Event Enable/Disable" kind="enum">
9003 <constant id="JVMTI_ENABLE" num="1">
9004 If <paramlink id="mode"></paramlink> is <code>JVMTI_ENABLE</code>,
9005 the event <paramlink id="event_type"></paramlink> will be enabled
9006 </constant>
9007 <constant id="JVMTI_DISABLE" num="0">
9008 If <paramlink id="mode"></paramlink> is <code>JVMTI_DISABLE</code>,
9009 the event <paramlink id="event_type"></paramlink> will be disabled
9010 </constant>
9011 </constants>
9012 If <code>thread</code> is <code>NULL</code>,
9013 the event is enabled or disabled globally; otherwise, it is
9014 enabled or disabled for a particular thread.
9015 An event is generated for
9016 a particular thread if it is enabled either at the thread or global
9017 levels.
9018 <p/>
9019 See <internallink id="EventIndex">below</internallink> for information on specific events.
9020 <p/>
9021 The following events cannot be controlled at the thread
9022 level through this function.
9023 <ul>
9024 <li><eventlink id="VMInit"></eventlink></li>
9025 <li><eventlink id="VMStart"></eventlink></li>
9026 <li><eventlink id="VMDeath"></eventlink></li>
9027 <li><eventlink id="ThreadStart"></eventlink></li>
9028 <li><eventlink id="CompiledMethodLoad"></eventlink></li>
9029 <li><eventlink id="CompiledMethodUnload"></eventlink></li>
9030 <li><eventlink id="DynamicCodeGenerated"></eventlink></li>
9031 <li><eventlink id="DataDumpRequest"></eventlink></li>
9032 </ul>
9033 <p/>
9034 Initially, no events are enabled at either the thread level
9035 or the global level.
9036 <p/>
9037 Any needed capabilities (see Event Enabling Capabilities below) must be possessed
9038 before calling this function.
9039 <p/>
9040 Details on events are
9041 described <internallink id="EventSection">below</internallink>.
9042 </description>
9043 <origin>jvmdiClone</origin>
9044 <eventcapabilities></eventcapabilities>
9045 <parameters>
9046 <param id="mode">
9047 <enum>jvmtiEventMode</enum>
9048 <description>
9049 <code>JVMTI_ENABLE</code> or <code>JVMTI_DISABLE</code>
9050 </description>
9051 </param>
9052 <param id="event_type">
9053 <enum>jvmtiEvent</enum>
9054 <description>
9055 the event to control
9056 </description>
9057 </param>
9058 <param id="event_thread">
9059 <ptrtype>
9060 <jthread impl="noconvert"/>
9061 <nullok>event is controlled at the global level</nullok>
9062 </ptrtype>
9063 <description>
9064 The thread to control
9065 </description>
9066 </param>
9067 <param id="...">
9068 <varargs/>
9069 <description>
9070 for future expansion
9071 </description>
9072 </param>
9073 </parameters>
9074 <errors>
9075 <error id="JVMTI_ERROR_INVALID_THREAD">
9076 <paramlink id="event_thread"/> is non-<code>NULL</code> and is not a valid thread.
9077 </error>
9078 <error id="JVMTI_ERROR_THREAD_NOT_ALIVE">
9079 <paramlink id="event_thread"/> is non-<code>NULL</code> and is not live (has not been started or is now dead).
9080 </error>
9081 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
9082 thread level control was attempted on events which do not
9083 permit thread level control.
9084 </error>
9085 <error id="JVMTI_ERROR_MUST_POSSESS_CAPABILITY">
9086 The Required Event Enabling Capability is not possessed.
9087 </error>
9088 </errors>
9089 </function>
9090
9091 <function id="GenerateEvents" num="123">
9092 <synopsis>Generate Events</synopsis>
9093 <description>
9094 Generate events to represent the current state of the VM.
9095 For example, if <paramlink id="event_type"/> is
9096 <code>JVMTI_EVENT_COMPILED_METHOD_LOAD</code>,
9097 a <eventlink id="CompiledMethodLoad"></eventlink> event will be
9098 sent for each currently compiled method.
9099 Methods that were loaded and now have been unloaded are not sent.
9100 The history of what events have previously been sent does not
9101 effect what events are sent by this function--for example,
9102 all currently compiled methods
9103 will be sent each time this function is called.
9104 <p/>
9105 This function is useful when
9106 events may have been missed due to the agent attaching after program
9107 execution begins; this function generates the missed events.
9108 <p/>
9109 Attempts to execute Java programming language code or
9110 JNI functions may be paused until this function returns -
9111 so neither should be called from the thread sending the event.
9112 This function returns only after the missed events have been
9113 sent, processed and have returned.
9114 The event may be sent on a different thread than the thread
9115 on which the event occurred.
9116 The callback for the event must be set with
9117 <functionlink id="SetEventCallbacks"></functionlink>
9118 and the event must be enabled with
9119 <functionlink id="SetEventNotificationMode"></functionlink>
9120 or the events will not occur.
9121 If the VM no longer has the information to generate some or
9122 all of the requested events, the events are simply not sent -
9123 no error is returned.
9124 <p/>
9125 Only the following events are supported:
9126 <ul>
9127 <li><eventlink id="CompiledMethodLoad"></eventlink></li>
9128 <li><eventlink id="DynamicCodeGenerated"></eventlink></li>
9129 </ul>
9130 </description>
9131 <origin>new</origin>
9132 <capabilities>
9133 <capability id="can_generate_compiled_method_load_events"></capability>
9134 </capabilities>
9135 <parameters>
9136 <param id="event_type">
9137 <enum>jvmtiEvent</enum>
9138 <description>
9139 The type of event to generate. Must be one of these:
9140 <ul>
9141 <li><eventlink id="CompiledMethodLoad"><code>JVMTI_EVENT_COMPILED_METHOD_LOAD</code></eventlink></li>
9142 <li><eventlink id="DynamicCodeGenerated"><code>JVMTI_EVENT_DYNAMIC_CODE_GENERATED</code></eventlink></li>
9143 </ul>
9144 </description>
9145 </param>
9146 </parameters>
9147 <errors>
9148 <error id="JVMTI_ERROR_MUST_POSSESS_CAPABILITY">
9149 <paramlink id="event_type"/> is
9150 <eventlink id="CompiledMethodLoad"><code>JVMTI_EVENT_COMPILED_METHOD_LOAD</code></eventlink>
9151 and <fieldlink id="can_generate_compiled_method_load_events" struct="jvmtiCapabilities"></fieldlink>
9152 is <code>false</code>.
9153 </error>
9154 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
9155 <paramlink id="event_type"/> is other than
9156 <eventlink id="CompiledMethodLoad"><code>JVMTI_EVENT_COMPILED_METHOD_LOAD</code></eventlink>
9157 or <eventlink id="DynamicCodeGenerated"><code>JVMTI_EVENT_DYNAMIC_CODE_GENERATED</code></eventlink>.
9158 </error>
9159 </errors>
9160 </function>
9161
9162 </category>
9163
9164 <category id="extension" label="Extension Mechanism">
9165
9166 <intro>
9167 These functions
9168 allow a <jvmti/> implementation to provide functions and events
9169 beyond those defined in this specification.
9170 <p/>
9171 Both extension functions and extension events have parameters
9172 each of which has a 'type' and 'kind' chosen from the following tables:
9173
9174 <constants id="jvmtiParamTypes" label="Extension Function/Event Parameter Types" kind="enum">
9175 <constant id="JVMTI_TYPE_JBYTE" num="101">
9176 Java programming language primitive type - <code>byte</code>.
9177 JNI type <code>jbyte</code>.
9178 </constant>
9179 <constant id="JVMTI_TYPE_JCHAR" num="102">
9180 Java programming language primitive type - <code>char</code>.
9181 JNI type <code>jchar</code>.
9182 </constant>
9183 <constant id="JVMTI_TYPE_JSHORT" num="103">
9184 Java programming language primitive type - <code>short</code>.
9185 JNI type <code>jshort</code>.
9186 </constant>
9187 <constant id="JVMTI_TYPE_JINT" num="104">
9188 Java programming language primitive type - <code>int</code>.
9189 JNI type <datalink id="jint"></datalink>.
9190 </constant>
9191 <constant id="JVMTI_TYPE_JLONG" num="105">
9192 Java programming language primitive type - <code>long</code>.
9193 JNI type <datalink id="jlong"></datalink>.
9194 </constant>
9195 <constant id="JVMTI_TYPE_JFLOAT" num="106">
9196 Java programming language primitive type - <code>float</code>.
9197 JNI type <datalink id="jfloat"></datalink>.
9198 </constant>
9199 <constant id="JVMTI_TYPE_JDOUBLE" num="107">
9200 Java programming language primitive type - <code>double</code>.
9201 JNI type <datalink id="jdouble"></datalink>.
9202 </constant>
9203 <constant id="JVMTI_TYPE_JBOOLEAN" num="108">
9204 Java programming language primitive type - <code>boolean</code>.
9205 JNI type <datalink id="jboolean"></datalink>.
9206 </constant>
9207 <constant id="JVMTI_TYPE_JOBJECT" num="109">
9208 Java programming language object type - <code>java.lang.Object</code>.
9209 JNI type <datalink id="jobject"></datalink>.
9210 Returned values are JNI local references and must be managed.
9211 </constant>
9212 <constant id="JVMTI_TYPE_JTHREAD" num="110">
9213 Java programming language object type - <code>java.lang.Thread</code>.
9214 <jvmti/> type <datalink id="jthread"></datalink>.
9215 Returned values are JNI local references and must be managed.
9216 </constant>
9217 <constant id="JVMTI_TYPE_JCLASS" num="111">
9218 Java programming language object type - <code>java.lang.Class</code>.
9219 JNI type <datalink id="jclass"></datalink>.
9220 Returned values are JNI local references and must be managed.
9221 </constant>
9222 <constant id="JVMTI_TYPE_JVALUE" num="112">
9223 Union of all Java programming language primitive and object types -
9224 JNI type <datalink id="jvalue"></datalink>.
9225 Returned values which represent object types are JNI local references and must be managed.
9226 </constant>
9227 <constant id="JVMTI_TYPE_JFIELDID" num="113">
9228 Java programming language field identifier -
9229 JNI type <datalink id="jfieldID"></datalink>.
9230 </constant>
9231 <constant id="JVMTI_TYPE_JMETHODID" num="114">
9232 Java programming language method identifier -
9233 JNI type <datalink id="jmethodID"></datalink>.
9234 </constant>
9235 <constant id="JVMTI_TYPE_CCHAR" num="115">
9236 C programming language type - <code>char</code>.
9237 </constant>
9238 <constant id="JVMTI_TYPE_CVOID" num="116">
9239 C programming language type - <code>void</code>.
9240 </constant>
9241 <constant id="JVMTI_TYPE_JNIENV" num="117">
9242 JNI environment - <code>JNIEnv</code>.
9243 Should be used with the correct <datalink id="jvmtiParamKind"/> to make it a pointer type.
9244 </constant>
9245 </constants>
9246
9247 <constants id="jvmtiParamKind" label="Extension Function/Event Parameter Kinds" kind="enum">
9248 <constant id="JVMTI_KIND_IN" num="91">
9249 Ingoing argument - <code>foo</code>.
9250 </constant>
9251 <constant id="JVMTI_KIND_IN_PTR" num="92">
9252 Ingoing pointer argument - <code>const foo*</code>.
9253 </constant>
9254 <constant id="JVMTI_KIND_IN_BUF" num="93">
9255 Ingoing array argument - <code>const foo*</code>.
9256 </constant>
9257 <constant id="JVMTI_KIND_ALLOC_BUF" num="94">
9258 Outgoing allocated array argument - <code>foo**</code>.
9259 Free with <code>Deallocate</code>.
9260 </constant>
9261 <constant id="JVMTI_KIND_ALLOC_ALLOC_BUF" num="95">
9262 Outgoing allocated array of allocated arrays argument - <code>foo***</code>.
9263 Free with <code>Deallocate</code>.
9264 </constant>
9265 <constant id="JVMTI_KIND_OUT" num="96">
9266 Outgoing argument - <code>foo*</code>.
9267 </constant>
9268 <constant id="JVMTI_KIND_OUT_BUF" num="97">
9269 Outgoing array argument (pre-allocated by agent) - <code>foo*</code>.
9270 Do not <code>Deallocate</code>.
9271 </constant>
9272 </constants>
9273
9274 </intro>
9275
9276 <typedef id="jvmtiParamInfo" label="Extension Function/Event Parameter Info">
9277 <field id="name">
9278 <allocfieldbuf><char/></allocfieldbuf>
9279 <description>
9280 The parameter name, encoded as a
9281 <internallink id="mUTF">modified UTF-8</internallink> string
9282 </description>
9283 </field>
9284 <field id="kind">
9285 <enum>jvmtiParamKind</enum>
9286 <description>
9287 The kind of the parameter - type modifiers
9288 </description>
9289 </field>
9290 <field id="base_type">
9291 <enum>jvmtiParamTypes</enum>
9292 <description>
9293 The base type of the parameter - modified by <code>kind</code>
9294 </description>
9295 </field>
9296 <field id="null_ok">
9297 <jboolean/>
9298 <description>
9299 Is a <code>NULL</code> argument permitted? Applies only to pointer and object types.
9300 </description>
9301 </field>
9302 </typedef>
9303
9304 <callback id="jvmtiExtensionFunction">
9305 <enum>jvmtiError</enum>
9306 <synopsis>Extension Function</synopsis>
9307 <description>
9308 This is the implementation-specific extension function.
9309 </description>
9310 <parameters>
9311 <param id="jvmti_env">
9312 <outptr>
9313 <struct>jvmtiEnv</struct>
9314 </outptr>
9315 <description>
9316 The <jvmti/> environment is the only fixed parameter for extension functions.
9317 </description>
9318 </param>
9319 <param id="...">
9320 <varargs/>
9321 <description>
9322 The extension function-specific parameters
9323 </description>
9324 </param>
9325 </parameters>
9326 </callback>
9327
9328 <function id="GetExtensionFunctions" phase="onload" num="124">
9329 <synopsis>Get Extension Functions</synopsis>
9330
9331 <typedef id="jvmtiExtensionFunctionInfo" label="Extension Function Info">
9332 <field id="func">
9333 <ptrtype>
9334 <struct>jvmtiExtensionFunction</struct>
9335 </ptrtype>
9336 <description>
9337 The actual function to call
9338 </description>
9339 </field>
9340 <field id="id">
9341 <allocfieldbuf><char/></allocfieldbuf>
9342 <description>
9343 The identifier for the extension function, encoded as a
9344 <internallink id="mUTF">modified UTF-8</internallink> string.
9345 Uses package name conventions.
9346 For example, <code>com.sun.hotspot.bar</code>
9347 </description>
9348 </field>
9349 <field id="short_description">
9350 <allocfieldbuf><char/></allocfieldbuf>
9351 <description>
9352 A one sentence description of the function, encoded as a
9353 <internallink id="mUTF">modified UTF-8</internallink> string.
9354 </description>
9355 </field>
9356 <field id="param_count">
9357 <jint/>
9358 <description>
9359 The number of parameters excluding <code>jvmtiEnv *jvmti_env</code>
9360 </description>
9361 </field>
9362 <field id="params">
9363 <allocfieldbuf outcount="param_count">
9364 <struct>jvmtiParamInfo</struct>
9365 </allocfieldbuf>
9366 <description>
9367 Array of
9368 <fieldlink id="param_count" struct="jvmtiExtensionFunctionInfo"></fieldlink>
9369 parameters (<code>jvmtiEnv *jvmti_env</code> excluded)
9370 </description>
9371 </field>
9372 <field id="error_count">
9373 <jint/>
9374 <description>
9375 The number of possible error returns (excluding universal errors)
9376 </description>
9377 </field>
9378 <field id="errors">
9379 <allocfieldbuf outcount="error_count">
9380 <enum>jvmtiError</enum>
9381 </allocfieldbuf>
9382 <description>
9383 Array of <fieldlink id="error_count" struct="jvmtiExtensionFunctionInfo"></fieldlink>
9384 possible errors
9385 </description>
9386 </field>
9387 </typedef>
9388
9389 <description>
9390 Returns the set of extension functions.
9391 </description>
9392 <origin>new</origin>
9393 <capabilities>
9394 </capabilities>
9395 <parameters>
9396 <param id="extension_count_ptr">
9397 <outptr><jint/></outptr>
9398 <description>
9399 On return, points to the number of extension functions
9400 </description>
9401 </param>
9402 <param id="extensions">
9403 <allocbuf outcount="extension_count_ptr"><struct>jvmtiExtensionFunctionInfo</struct></allocbuf>
9404 <description>
9405 Returns an array of extension function info, one per function
9406 </description>
9407 </param>
9408 </parameters>
9409 <errors>
9410 </errors>
9411 </function>
9412
9413 <function id="GetExtensionEvents" phase="onload" num="125">
9414 <synopsis>Get Extension Events</synopsis>
9415
9416 <typedef id="jvmtiExtensionEventInfo" label="Extension Event Info">
9417 <field id="extension_event_index">
9418 <jint/>
9419 <description>
9420 The identifying index of the event
9421 </description>
9422 </field>
9423 <field id="id">
9424 <allocfieldbuf><char/></allocfieldbuf>
9425 <description>
9426 The identifier for the extension event, encoded as a
9427 <internallink id="mUTF">modified UTF-8</internallink> string.
9428 Uses package name conventions.
9429 For example, <code>com.sun.hotspot.bar</code>
9430 </description>
9431 </field>
9432 <field id="short_description">
9433 <allocfieldbuf><char/></allocfieldbuf>
9434 <description>
9435 A one sentence description of the event, encoded as a
9436 <internallink id="mUTF">modified UTF-8</internallink> string.
9437 </description>
9438 </field>
9439 <field id="param_count">
9440 <jint/>
9441 <description>
9442 The number of parameters excluding <code>jvmtiEnv *jvmti_env</code>
9443 </description>
9444 </field>
9445 <field id="params">
9446 <allocfieldbuf outcount="param_count">
9447 <struct>jvmtiParamInfo</struct>
9448 </allocfieldbuf>
9449 <description>
9450 Array of
9451 <fieldlink id="param_count" struct="jvmtiExtensionEventInfo"></fieldlink>
9452 parameters (<code>jvmtiEnv *jvmti_env</code> excluded)
9453 </description>
9454 </field>
9455 </typedef>
9456
9457 <description>
9458 Returns the set of extension events.
9459 </description>
9460 <origin>new</origin>
9461 <capabilities>
9462 </capabilities>
9463 <parameters>
9464 <param id="extension_count_ptr">
9465 <outptr><jint/></outptr>
9466 <description>
9467 On return, points to the number of extension events
9468 </description>
9469 </param>
9470 <param id="extensions">
9471 <allocbuf outcount="extension_count_ptr"><struct>jvmtiExtensionEventInfo</struct></allocbuf>
9472 <description>
9473 Returns an array of extension event info, one per event
9474 </description>
9475 </param>
9476 </parameters>
9477 <errors>
9478 </errors>
9479 </function>
9480
9481 <callback id="jvmtiExtensionEvent">
9482 <void/>
9483 <synopsis>Extension Event</synopsis>
9484 <description>
9485 This is the implementation-specific event.
9486 The event handler is set with
9487 <functionlink id="SetExtensionEventCallback"/>.
9488 <p/>
9489 Event handlers for extension events must be declared varargs to match this definition.
9490 Failure to do so could result in calling convention mismatch and undefined behavior
9491 on some platforms.
9492 <p/>
9493 For example, if the <code>jvmtiParamInfo</code>
9494 returned by <functionlink id="GetExtensionEvents"/> indicates that
9495 there is a <code>jint</code> parameter, the event handler should be
9496 declared:
9497 <example>
9498 void JNICALL myHandler(jvmtiEnv* jvmti_env, jint myInt, ...)
9499 </example>
9500 Note the terminal "<code>...</code>" which indicates varargs.
9501 </description>
9502 <parameters>
9503 <param id="jvmti_env">
9504 <outptr>
9505 <struct>jvmtiEnv</struct>
9506 </outptr>
9507 <description>
9508 The <jvmti/> environment is the only fixed parameter for extension events.
9509 </description>
9510 </param>
9511 <param id="...">
9512 <varargs/>
9513 <description>
9514 The extension event-specific parameters
9515 </description>
9516 </param>
9517 </parameters>
9518 </callback>
9519
9520 <function id="SetExtensionEventCallback" phase="onload" num="126">
9521 <synopsis>Set Extension Event Callback</synopsis>
9522
9523 <description>
9524 Sets the callback function for an extension event and
9525 enables the event. Or, if the callback is <code>NULL</code>, disables
9526 the event. Note that unlike standard events, setting
9527 the callback and enabling the event are a single operation.
9528 </description>
9529 <origin>new</origin>
9530 <capabilities>
9531 </capabilities>
9532 <parameters>
9533 <param id="extension_event_index">
9534 <jint/>
9535 <description>
9536 Identifies which callback to set.
9537 This index is the
9538 <fieldlink id="extension_event_index" struct="jvmtiExtensionEventInfo"></fieldlink>
9539 field of
9540 <datalink id="jvmtiExtensionEventInfo"/>.
9541 </description>
9542 </param>
9543 <param id="callback">
9544 <ptrtype>
9545 <struct>jvmtiExtensionEvent</struct>
9546 <nullok>disable the event</nullok>
9547 </ptrtype>
9548 <description>
9549 If <code>callback</code> is non-<code>NULL</code>,
9550 set <code>callback</code> to be the event callback function
9551 and enable the event.
9552 </description>
9553 </param>
9554 </parameters>
9555 <errors>
9556 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
9557 <paramlink id="extension_event_index"/> is not an
9558 <fieldlink id="extension_event_index"
9559 struct="jvmtiExtensionEventInfo"/>
9560 returned by
9561 <functionlink id="GetExtensionEvents"/>
9562 </error>
9563 </errors>
9564 </function>
9565
9566 </category>
9567
9568 <category id="capability" label="Capability">
9569
9570 <intro>
9571 The capabilities functions allow you to change the
9572 functionality available to <jvmti/>--that is,
9573 which <jvmti/>
9574 functions can be called, what events can be generated,
9575 and what functionality these events and functions can
9576 provide.
9577 <p/>
9578 The "Capabilities" section of each function and event describe which
9579 capabilities, if any, they are associated with. "Required Functionality"
9580 means it is available for use and no capabilities must be added to use it.
9581 "Optional Functionality" means the agent must possess the capability
9582 before it can be used.
9583 To possess a capability, the agent must
9584 <functionlink id="AddCapabilities">add the capability</functionlink>.
9585 "Optional Features" describe capabilities which,
9586 if added, extend the feature set.
9587 <p/>
9588 The potentially available capabilities of each <jvmti/> implementation are different.
9589 Depending on the implementation, a capability:
9590 <ul>
9591 <li>may never be added</li>
9592 <li>may be added in either the <code>OnLoad</code> or live phase in any environment</li>
9593 <li>may be added only during the <code>OnLoad</code> phase</li>
9594 <li>may be possessed by only one environment at a time</li>
9595 <li>may be possessed by only one environment at a time,
9596 and only during the <code>OnLoad</code> phase</li>
9597 <li>and so on ...</li>
9598 </ul>
9599 Frequently, the addition of a capability may incur a cost in execution speed, start up
9600 time, and/or memory footprint. Note that the overhead of using a capability
9601 is completely different than the overhead of possessing a capability.
9602 Take single stepping as an example. When single stepping is on (that
9603 is, when the event is enabled and thus actively sending events)
9604 the overhead of sending and processing an event
9605 on each instruction is huge in any implementation.
9606 However, the overhead of possessing the capability may be small or large,
9607 depending on the implementation. Also, when and if a capability is potentially
9608 available depends on the implementation. Some examples:
9609 <ul>
9610 <li>One VM might perform all execution by compiling bytecodes into
9611 native code and be unable to generate single step instructions.
9612 In this implementation the capability can not be added.</li>
9613 <li>Another VM may be able to switch execution to a single stepping
9614 interpreter at any time. In this implementation, having the capability has no
9615 overhead and could be added at any time.</li>
9616 <li>Yet another VM might be able to choose a bytecode compiling or single stepping capable interpreted
9617 execution engine at start up, but be unable to switch between them.
9618 In this implementation the capability would need to be added
9619 during the <code>OnLoad</code> phase (before bytecode
9620 execution begins) and would have a large impact on execution speed
9621 even if single stepping was never used.</li>
9622 <li>Still another VM might be able to add an "is single stepping on" check
9623 into compiled bytecodes or a generated interpreter. Again in this implementation
9624 the capability would need to be added during the <code>OnLoad</code> phase but the overhead (a test
9625 and branch on each instruction) would be considerably less.</li>
9626 </ul>
9627 <p/>
9628 Each <jvmti/> <internallink id="environments">environment</internallink>
9629 has its own set of capabilities.
9630 Initially, that set is empty.
9631 Any desired capability must be added.
9632 If possible, capabilities should be added during the <code>OnLoad</code> phase. For most
9633 virtual machines certain capabilities require special set up for
9634 the virtual machine and this set up must happen
9635 during the <code>OnLoad</code> phase, before the virtual machine begins execution.
9636 Once a capability is added, it can
9637 only be removed if explicitly relinquished by the environment.
9638 <p/>
9639 The agent can,
9640 <functionlink id="GetPotentialCapabilities">determine what
9641 capabilities this VM can potentially provide</functionlink>,
9642 <functionlink id="AddCapabilities">add the capabilities
9643 to be used</functionlink>,
9644 <functionlink id="RelinquishCapabilities">release capabilities
9645 which are no longer needed</functionlink>, and
9646 <functionlink id="GetCapabilities">examine the currently available
9647 capabilities</functionlink>.
9648 </intro>
9649
9650 <intro id="capabilityExamples" label="Capability Examples">
9651 For example, a freshly started agent (in the <code>OnLoad</code> function)
9652 wants to enable all possible capabilities.
9653 Note that, in general, this is not advisable as the agent may suffer
9654 a performance penalty for functionality it is not using.
9655 The code might look like this in C:
9656 <example>
9657 jvmtiCapabilities capa;
9658 jvmtiError err;
9659
9660 err = (*jvmti)->GetPotentialCapabilities(jvmti, &capa);
9661 if (err == JVMTI_ERROR_NONE) {
9662 err = (*jvmti)->AddCapabilities(jvmti, &capa);
9663 </example>
9664 For example, if an agent wants to check if it can get
9665 the bytecodes of a method (that is, it wants to check
9666 if it previously added this capability and has not
9667 relinquished it), the code might
9668 look like this in C:
9669 <example>
9670 jvmtiCapabilities capa;
9671 jvmtiError err;
9672
9673 err = (*jvmti)->GetCapabilities(jvmti, &capa);
9674 if (err == JVMTI_ERROR_NONE) {
9675 if (capa.can_get_bytecodes) { ... } }
9676 </example>
9677 </intro>
9678
9679 <capabilitiestypedef id="jvmtiCapabilities" label="The Capabilities Structure">
9680 <description>
9681 The functions in this category use this capabilities structure
9682 which contains boolean flags corresponding to each capability:
9683 </description>
9684 <capabilityfield id="can_tag_objects">
9685 <description>
9686 Can set and get tags, as described in the
9687 <internallink id="Heap">Heap category</internallink>.
9688 </description>
9689 </capabilityfield>
9690 <capabilityfield id="can_generate_field_modification_events">
9691 <description>
9692 Can set watchpoints on field modification -
9693 <functionlink id="SetFieldModificationWatch"></functionlink>
9694 </description>
9695 </capabilityfield>
9696 <capabilityfield id="can_generate_field_access_events">
9697 <description>
9698 Can set watchpoints on field access -
9699 <functionlink id="SetFieldAccessWatch"></functionlink>
9700 </description>
9701 </capabilityfield>
9702 <capabilityfield id="can_get_bytecodes">
9703 <description>
9704 Can get bytecodes of a method <functionlink id="GetBytecodes"></functionlink>
9705 </description>
9706 </capabilityfield>
9707 <capabilityfield id="can_get_synthetic_attribute">
9708 <description>
9709 Can test if a field or method is synthetic -
9710 <functionlink id="IsFieldSynthetic"></functionlink> and
9711 <functionlink id="IsMethodSynthetic"></functionlink>
9712 </description>
9713 </capabilityfield>
9714 <capabilityfield id="can_get_owned_monitor_info">
9715 <description>
9716 Can get information about ownership of monitors -
9717 <functionlink id="GetOwnedMonitorInfo"></functionlink>
9718 </description>
9719 </capabilityfield>
9720 <capabilityfield id="can_get_current_contended_monitor">
9721 <description>
9722 Can <functionlink id="GetCurrentContendedMonitor"></functionlink>
9723 </description>
9724 </capabilityfield>
9725 <capabilityfield id="can_get_monitor_info">
9726 <description>
9727 Can <functionlink id="GetObjectMonitorUsage"></functionlink>
9728 </description>
9729 </capabilityfield>
9730 <capabilityfield id="can_pop_frame">
9731 <description>
9732 Can pop frames off the stack - <functionlink id="PopFrame"></functionlink>
9733 </description>
9734 </capabilityfield>
9735 <capabilityfield id="can_redefine_classes">
9736 <description>
9737 Can redefine classes with <functionlink id="RedefineClasses"/>.
9738 </description>
9739 </capabilityfield>
9740 <capabilityfield id="can_signal_thread">
9741 <description>
9742 Can send stop or interrupt to threads
9743 </description>
9744 </capabilityfield>
9745 <capabilityfield id="can_get_source_file_name">
9746 <description>
9747 Can get the source file name of a class
9748 </description>
9749 </capabilityfield>
9750 <capabilityfield id="can_get_line_numbers">
9751 <description>
9752 Can get the line number table of a method
9753 </description>
9754 </capabilityfield>
9755 <capabilityfield id="can_get_source_debug_extension">
9756 <description>
9757 Can get the source debug extension of a class
9758 </description>
9759 </capabilityfield>
9760 <capabilityfield id="can_access_local_variables">
9761 <description>
9762 Can set and get local variables
9763 </description>
9764 </capabilityfield>
9765 <capabilityfield id="can_maintain_original_method_order">
9766 <description>
9767 Can return methods in the order they occur in the class file
9768 </description>
9769 </capabilityfield>
9770 <capabilityfield id="can_generate_single_step_events">
9771 <description>
9772 Can get <eventlink id="SingleStep">single step</eventlink> events
9773 </description>
9774 </capabilityfield>
9775 <capabilityfield id="can_generate_exception_events">
9776 <description>
9777 Can get <eventlink id="Exception">exception thrown</eventlink> and
9778 <eventlink id="ExceptionCatch">exception catch</eventlink> events
9779 </description>
9780 </capabilityfield>
9781 <capabilityfield id="can_generate_frame_pop_events">
9782 <description>
9783 Can <functionlink id="NotifyFramePop">set</functionlink> and thus get
9784 <eventlink id="FramePop"></eventlink> events
9785 </description>
9786 </capabilityfield>
9787 <capabilityfield id="can_generate_breakpoint_events">
9788 <description>
9789 Can <functionlink id="SetBreakpoint">set</functionlink> and thus get
9790 <eventlink id="Breakpoint"></eventlink> events
9791 </description>
9792 </capabilityfield>
9793 <capabilityfield id="can_suspend">
9794 <description>
9795 Can suspend and resume threads
9796 </description>
9797 </capabilityfield>
9798 <capabilityfield id="can_redefine_any_class">
9799 <description>
9800 Can modify (retransform or redefine) any non-primitive non-array class.
9801 See <functionlink id="IsModifiableClass"/>.
9802 </description>
9803 </capabilityfield>
9804 <capabilityfield id="can_get_current_thread_cpu_time">
9805 <description>
9806 Can <functionlink id="GetCurrentThreadCpuTime">get</functionlink>
9807 current thread CPU time
9808 </description>
9809 </capabilityfield>
9810 <capabilityfield id="can_get_thread_cpu_time">
9811 <description>
9812 Can <functionlink id="GetThreadCpuTime">get</functionlink>
9813 thread CPU time
9814 </description>
9815 </capabilityfield>
9816 <capabilityfield id="can_generate_method_entry_events"
9817 disp1="can_generate" disp2="_method_entry_events"
9818 >
9819 <description>
9820 Can generate method entry events on entering a method
9821 </description>
9822 </capabilityfield>
9823 <capabilityfield id="can_generate_method_exit_events"
9824 disp1="can_generate" disp2="_method_exit_events"
9825 >
9826 <description>
9827 Can generate method exit events on leaving a method
9828 </description>
9829 </capabilityfield>
9830 <capabilityfield id="can_generate_all_class_hook_events"
9831 disp1="can_generate" disp2="_all_class_hook_events"
9832 >
9833 <description>
9834 Can generate ClassFileLoadHook events for every loaded class.
9835 </description>
9836 </capabilityfield>
9837 <capabilityfield id="can_generate_compiled_method_load_events"
9838 disp1="can_generate" disp2="_compiled_method_load_events"
9839 >
9840 <description>
9841 Can generate events when a method is compiled or unloaded
9842 </description>
9843 </capabilityfield>
9844 <capabilityfield id="can_generate_monitor_events"
9845 disp1="can_generate" disp2="_monitor_events"
9846 >
9847 <description>
9848 Can generate events on monitor activity
9849 </description>
9850 </capabilityfield>
9851 <capabilityfield id="can_generate_vm_object_alloc_events"
9852 disp1="can_generate" disp2="_vm_object_alloc_events"
9853 >
9854 <description>
9855 Can generate events on VM allocation of an object
9856 </description>
9857 </capabilityfield>
9858 <capabilityfield id="can_generate_native_method_bind_events"
9859 disp1="can_generate" disp2="_native_method_bind_events"
9860 >
9861 <description>
9862 Can generate events when a native method is bound to its
9863 implementation
9864 </description>
9865 </capabilityfield>
9866 <capabilityfield id="can_generate_garbage_collection_events"
9867 disp1="can_generate" disp2="_garbage_collection_events"
9868 >
9869 <description>
9870 Can generate events when garbage collection begins or ends
9871 </description>
9872 </capabilityfield>
9873 <capabilityfield id="can_generate_object_free_events"
9874 disp1="can_generate" disp2="_object_free_events"
9875 >
9876 <description>
9877 Can generate events when the garbage collector frees an object
9878 </description>
9879 </capabilityfield>
9880 <capabilityfield id="can_force_early_return" since="1.1">
9881 <description>
9882 Can return early from a method, as described in the
9883 <internallink id="ForceEarlyReturn">Force Early Return category</internallink>.
9884 </description>
9885 </capabilityfield>
9886 <capabilityfield id="can_get_owned_monitor_stack_depth_info" since="1.1">
9887 <description>
9888 Can get information about owned monitors with stack depth -
9889 <functionlink id="GetOwnedMonitorStackDepthInfo"></functionlink>
9890 </description>
9891 </capabilityfield>
9892 <capabilityfield id="can_get_constant_pool" since="1.1">
9893 <description>
9894 Can get the constant pool of a class -
9895 <functionlink id="GetConstantPool"></functionlink>
9896 </description>
9897 </capabilityfield>
9898 <capabilityfield id="can_set_native_method_prefix" since="1.1">
9899 <description>
9900 Can set prefix to be applied when native method cannot be resolved -
9901 <functionlink id="SetNativeMethodPrefix"/> and
9902 <functionlink id="SetNativeMethodPrefixes"/>
9903 </description>
9904 </capabilityfield>
9905 <capabilityfield id="can_retransform_classes" since="1.1">
9906 <description>
9907 Can retransform classes with <functionlink id="RetransformClasses"/>.
9908 In addition to the restrictions imposed by the specific
9909 implementation on this capability (see the
9910 <internallink id="capability">Capability</internallink> section),
9911 this capability must be set before the
9912 <eventlink id="ClassFileLoadHook"/> event is enabled for the
9913 first time in this environment.
9914 An environment that possesses this capability at the time that
9915 <code>ClassFileLoadHook</code> is enabled for the first time is
9916 said to be <i>retransformation capable</i>.
9917 An environment that does not possess this capability at the time that
9918 <code>ClassFileLoadHook</code> is enabled for the first time is
9919 said to be <i>retransformation incapable</i>.
9920 </description>
9921 </capabilityfield>
9922 <capabilityfield id="can_retransform_any_class" since="1.1">
9923 <description>
9924 <functionlink id="RetransformClasses"/> can be called on any class
9925 (<fieldlink id="can_retransform_classes" struct="jvmtiCapabilities"/>
9926 must also be set)
9927 </description>
9928 </capabilityfield>
9929 <capabilityfield id="can_generate_resource_exhaustion_heap_events" since="1.1">
9930 <description>
9931 Can generate events when the VM is unable to allocate memory from
9932 the <tm>Java</tm> platform heap.
9933 See <eventlink id="ResourceExhausted"/>.
9934 </description>
9935 </capabilityfield>
9936 <capabilityfield id="can_generate_resource_exhaustion_threads_events" since="1.1">
9937 <description>
9938 Can generate events when the VM is unable to create a thread.
9939 See <eventlink id="ResourceExhausted"/>.
9940 </description>
9941 </capabilityfield>
9942 </capabilitiestypedef>
9943
9944 <function id="GetPotentialCapabilities" jkernel="yes" phase="onload" num="140">
9945 <synopsis>Get Potential Capabilities</synopsis>
9946 <description>
9947 Returns via <paramlink id="capabilities_ptr"></paramlink> the <jvmti/>
9948 features that can potentially be possessed by this environment
9949 at this time.
9950 The returned capabilities differ from the complete set of capabilities
9951 implemented by the VM in two cases: another environment possesses
9952 capabilities that can only be possessed by one environment, or the
9953 current <functionlink id="GetPhase">phase</functionlink> is live,
9954 and certain capabilities can only be added during the <code>OnLoad</code> phase.
9955 The <functionlink id="AddCapabilities"></functionlink> function
9956 may be used to set any or all or these capabilities.
9957 Currently possessed capabilities are included.
9958 <p/>
9959 Typically this function is used in the <code>OnLoad</code> function.
9960 Some virtual machines may allow a limited set of capabilities to be
9961 added in the live phase.
9962 In this case, the set of potentially available capabilities
9963 will likely differ from the <code>OnLoad</code> phase set.
9964 <p/>
9965 See the
9966 <internallink id="capabilityExamples">Capability Examples</internallink>.
9967 </description>
9968 <origin>new</origin>
9969 <capabilities>
9970 </capabilities>
9971 <parameters>
9972 <param id="capabilities_ptr">
9973 <outptr><struct>jvmtiCapabilities</struct></outptr>
9974 <description>
9975 On return, points to the <jvmti/> capabilities that may be added.
9976 </description>
9977 </param>
9978 </parameters>
9979 <errors>
9980 </errors>
9981 </function>
9982
9983 <elide>
9984 <function id="EstimateCostOfCapabilities" phase="onload" num="141">
9985 <synopsis>Estimate Cost Of Capabilities</synopsis>
9986 <description>
9987 <issue>There is strong opposition to this function. The concern is
9988 that it would be difficult or impossible to provide meaningful
9989 numbers, as the amount of impact is conditional on many factors
9990 that a single number could not represent. There is doubt that
9991 conditional implementations would be used or are even a good idea.
9992 The thought is that release documentation for the implementation
9993 would be the best means of exposing this information.
9994 Unless new arguments are presented, I intend to remove this
9995 function in the next revision.
9996 </issue>
9997 <p/>
9998 Return via the <paramlink id="time_impact_ptr"></paramlink> and
9999 <paramlink id="space_impact_ptr"></paramlink> an estimate of the impact
10000 of adding the capabilities pointed to by
10001 <paramlink id="capabilities_ptr"></paramlink>.
10002 The returned estimates are in percentage of additional overhead, thus
10003 a time impact of 100 mean the application might run
10004 at half the speed.
10005 The estimates are very rough approximations and are not guaranteed.
10006 Note also, that the estimates are of the impact of having the
10007 capability available--when and if it is used the impact may be
10008 much greater.
10009 Estimates can be for a single capability or for a set of
10010 capabilities. Note that the costs are not necessarily additive,
10011 adding support for one capability might make another available
10012 for free or conversely having two capabilities at once may
10013 have multiplicative impact.
10014 Estimates are relative to the current set of capabilities -
10015 that is, how much more impact given the currently possessed capabilities.
10016 <p/>
10017 Typically this function is used in the OnLoad function,
10018 some virtual machines may allow a limited set of capabilities to be
10019 added in the live phase.
10020 In this case, the set of potentially available capabilities
10021 will likely differ from the OnLoad phase set.
10022 <p/>
10023 See the
10024 <internallink id="capabilityExamples">Capability Examples</internallink>.
10025 </description>
10026 <origin>new</origin>
10027 <capabilities>
10028 </capabilities>
10029 <parameters>
10030 <param id="capabilities_ptr">
10031 <inptr><struct>jvmtiCapabilities</struct></inptr>
10032 <description>
10033 points to the <jvmti/> capabilities to evaluate.
10034 </description>
10035 </param>
10036 <param id="time_impact_ptr">
10037 <outptr><jint/></outptr>
10038 <description>
10039 On return, points to the estimated percentage increase in
10040 run time if this capability was added.
10041 </description>
10042 </param>
10043 <param id="space_impact_ptr">
10044 <outptr><jint/></outptr>
10045 <description>
10046 On return, points to the estimated percentage increase in
10047 memory space used if this capability was added.
10048 </description>
10049 </param>
10050 </parameters>
10051 <errors>
10052 <error id="JVMTI_ERROR_NOT_AVAILABLE">
10053 The desired capabilities are not even potentially available.
10054 </error>
10055 </errors>
10056 </function>
10057 </elide>
10058
10059 <function id="AddCapabilities" jkernel="yes" phase="onload" num="142">
10060 <synopsis>Add Capabilities</synopsis>
10061 <description>
10062 Set new capabilities by adding the capabilities
10063 whose values are set to one (<code>1</code>) in
10064 <code>*</code><paramlink id="capabilities_ptr"></paramlink>.
10065 All previous capabilities are retained.
10066 Typically this function is used in the <code>OnLoad</code> function.
10067 Some virtual machines may allow a limited set of capabilities to be
10068 added in the live phase.
10069 <p/>
10070 See the
10071 <internallink id="capabilityExamples">Capability Examples</internallink>.
10072 </description>
10073 <origin>new</origin>
10074 <capabilities>
10075 </capabilities>
10076 <parameters>
10077 <param id="capabilities_ptr">
10078 <inptr><struct>jvmtiCapabilities</struct></inptr>
10079 <description>
10080 Points to the <jvmti/> capabilities to add.
10081 </description>
10082 </param>
10083 </parameters>
10084 <errors>
10085 <error id="JVMTI_ERROR_NOT_AVAILABLE">
10086 The desired capabilities are not even potentially available.
10087 </error>
10088 </errors>
10089 </function>
10090
10091
10092 <function id="RelinquishCapabilities" phase="onload" num="143">
10093 <synopsis>Relinquish Capabilities</synopsis>
10094 <description>
10095 Relinquish the capabilities
10096 whose values are set to one (<code>1</code>) in
10097 <code>*</code><paramlink id="capabilities_ptr"></paramlink>.
10098 Some implementations may allow only one environment to have a capability
10099 (see the <internallink id="capability">capability introduction</internallink>).
10100 This function releases capabilities
10101 so that they may be used by other agents.
10102 All other capabilities are retained.
10103 The capability will no longer be present in <functionlink id="GetCapabilities"></functionlink>.
10104 Attempting to relinquish a capability that the agent does not possess is not an error.
10105 <issue>
10106 It is possible for the agent to be actively using capabilities
10107 which are being relinquished. For example, a thread is currently
10108 suspended and can_suspend is being relinquished or an event is currently
10109 enabled and can_generate_whatever is being relinquished.
10110 There are three possible ways we could spec this:
10111 <ul>
10112 <li>relinquish automatically releases them</li>
10113 <li>relinquish checks and returns some error code if held</li>
10114 <li>it is the agent's responsibility and it is not checked</li>
10115 </ul>
10116 One of these should be chosen.
10117 </issue>
10118 </description>
10119 <origin>new</origin>
10120 <capabilities>
10121 </capabilities>
10122 <parameters>
10123 <param id="capabilities_ptr">
10124 <inptr><struct>jvmtiCapabilities</struct></inptr>
10125 <description>
10126 Points to the <jvmti/> capabilities to relinquish.
10127 </description>
10128 </param>
10129 </parameters>
10130 <errors>
10131 </errors>
10132 </function>
10133
10134
10135
10136 <function id="GetCapabilities" jkernel="yes" phase="any" num="89">
10137 <synopsis>Get Capabilities</synopsis>
10138 <description>
10139 Returns via <paramlink id="capabilities_ptr"></paramlink> the optional <jvmti/>
10140 features which this environment currently possesses.
10141 Each possessed capability is indicated by a one (<code>1</code>) in the
10142 corresponding field of the <internallink id="jvmtiCapabilities">capabilities
10143 structure</internallink>.
10144 An environment does not possess a capability unless it has been successfully added with
10145 <functionlink id="AddCapabilities"/>.
10146 An environment only loses possession of a capability if it has been relinquished with
10147 <functionlink id="RelinquishCapabilities"/>. Thus, this function returns the net result
10148 of the <code>AddCapabilities</code> and <code>RelinquishCapabilities</code> calls which
10149 have been made.
10150 <p/>
10151 See the
10152 <internallink id="capabilityExamples">Capability Examples</internallink>.
10153 </description>
10154 <origin>jvmdiClone</origin>
10155 <capabilities>
10156 </capabilities>
10157 <parameters>
10158 <param id="capabilities_ptr">
10159 <outptr><struct>jvmtiCapabilities</struct></outptr>
10160 <description>
10161 On return, points to the <jvmti/> capabilities.
10162 </description>
10163 </param>
10164 </parameters>
10165 <errors>
10166 </errors>
10167 </function>
10168
10169 </category>
10170
10171
10172 <category id="timers" label="Timers">
10173
10174 <intro>
10175 These functions provide timing information.
10176 The resolution at which the time is updated is not specified.
10177 They provides nanosecond precision, but not necessarily nanosecond accuracy.
10178 Details about the timers, such as their maximum values, can be accessed with
10179 the timer information functions.
10180 </intro>
10181
10182 <typedef id="jvmtiTimerInfo" label="Timer Info">
10183 <description>
10184 The information function for each timer returns this data structure.
10185 </description>
10186 <field id="max_value">
10187 <jlong/>
10188 <description>
10189 The maximum value the timer can reach.
10190 After this value is reached the timer wraps back to zero.
10191 This is an unsigned value. If tested or printed as a jlong (signed value)
10192 it may appear to be a negative number.
10193 </description>
10194 </field>
10195 <field id="may_skip_forward">
10196 <jboolean/>
10197 <description>
10198 If true, the timer can be externally adjusted and as a result skip forward.
10199 If false, the timer value will never increase faster than real time.
10200 </description>
10201 </field>
10202 <field id="may_skip_backward">
10203 <jboolean/>
10204 <description>
10205 If true, the timer can be externally adjusted and as a result skip backward.
10206 If false, the timer value will be monotonically increasing.
10207 </description>
10208 </field>
10209 <field id="kind">
10210 <enum>jvmtiTimerKind</enum>
10211 <description>
10212 The kind of timer.
10213 On a platform that does not distinguish between user and system time, <datalink
10214 id="JVMTI_TIMER_TOTAL_CPU"><code>JVMTI_TIMER_TOTAL_CPU</code></datalink>
10215 is returned.
10216 </description>
10217 </field>
10218 <field id="reserved1">
10219 <jlong/>
10220 <description>
10221 Reserved for future use.
10222 </description>
10223 </field>
10224 <field id="reserved2">
10225 <jlong/>
10226 <description>
10227 Reserved for future use.
10228 </description>
10229 </field>
10230 </typedef>
10231
10232 <intro>
10233 Where the timer kind is --
10234
10235 <constants id="jvmtiTimerKind" label="Timer Kinds" kind="enum">
10236 <constant id="JVMTI_TIMER_USER_CPU" num="30">
10237 CPU time that a thread is in user mode.
10238 </constant>
10239 <constant id="JVMTI_TIMER_TOTAL_CPU" num="31">
10240 CPU time that a thread is in user or system mode.
10241 </constant>
10242 <constant id="JVMTI_TIMER_ELAPSED" num="32">
10243 Elapsed time.
10244 </constant>
10245 </constants>
10246 </intro>
10247
10248 <function id="GetCurrentThreadCpuTimerInfo" callbacksafe="safe" impl="innative notrace" phase="start" num="134">
10249 <synopsis>Get Current Thread CPU Timer Information</synopsis>
10250 <description>
10251 Get information about the
10252 <functionlink id="GetCurrentThreadCpuTime"/> timer.
10253 The fields of the <datalink id="jvmtiTimerInfo"/> structure
10254 are filled in with details about the timer.
10255 This information is specific to the platform and the implementation of
10256 <functionlink id="GetCurrentThreadCpuTime"/> and thus
10257 does not vary by thread nor does it vary
10258 during a particular invocation of the VM.
10259 <p/>
10260 Note that the implementations of <functionlink id="GetCurrentThreadCpuTime"/>
10261 and <functionlink id="GetThreadCpuTime"/> may differ, and thus the values
10262 returned by <code>GetCurrentThreadCpuTimerInfo</code>
10263 and <functionlink id="GetThreadCpuTimerInfo"/>
10264 may differ -- see <functionlink id="GetCurrentThreadCpuTime"/> for more information.
10265 </description>
10266 <origin>new</origin>
10267 <capabilities>
10268 <required id="can_get_current_thread_cpu_time">
10269 Can get current thread CPU time.
10270 </required>
10271 </capabilities>
10272 <parameters>
10273 <param id="info_ptr">
10274 <outptr><struct>jvmtiTimerInfo</struct></outptr>
10275 <description>
10276 On return, filled with information describing the time
10277 returned by <functionlink id="GetCurrentThreadCpuTime"/>.
10278 </description>
10279 </param>
10280 </parameters>
10281 <errors>
10282 </errors>
10283 </function>
10284
10285 <function id="GetCurrentThreadCpuTime" callbacksafe="safe" impl="innative notrace" phase="start" num="135">
10286 <synopsis>Get Current Thread CPU Time</synopsis>
10287 <description>
10288 Return the CPU time utilized by the current thread.
10289 <p/>
10290 Note that the <functionlink id="GetThreadCpuTime"/>
10291 function provides CPU time for any thread, including
10292 the current thread. <code>GetCurrentThreadCpuTime</code>
10293 exists to support platforms which cannot
10294 supply CPU time for threads other than the current
10295 thread or which have more accurate information for
10296 the current thread (see
10297 <functionlink id="GetCurrentThreadCpuTimerInfo"/> vs
10298 <functionlink id="GetThreadCpuTimerInfo"/>).
10299 On many platforms this call will be equivalent to:
10300 <example>
10301 GetThreadCpuTime(env, NULL, nanos_ptr)
10302 </example>
10303 </description>
10304 <origin>new</origin>
10305 <capabilities>
10306 <required id="can_get_current_thread_cpu_time">
10307 Can get current thread CPU time.
10308 <p/>
10309 If this capability is enabled after threads have started,
10310 the implementation may choose any time up
10311 to and including the time that the capability is enabled
10312 as the point where CPU time collection starts.
10313 <p/>
10314 This capability must be potentially available on any
10315 platform where
10316 <internallink id="jvmtiCapabilities.can_get_thread_cpu_time"><code>can_get_thread_cpu_time</code></internallink>
10317 is potentially available.
10318 </required>
10319 </capabilities>
10320 <parameters>
10321 <param id="nanos_ptr">
10322 <outptr><jlong/></outptr>
10323 <description>
10324 On return, points to the CPU time used by this thread
10325 in nanoseconds.
10326 This is an unsigned value. If tested or printed as a jlong (signed value)
10327 it may appear to be a negative number.
10328 </description>
10329 </param>
10330 </parameters>
10331 <errors>
10332 </errors>
10333 </function>
10334
10335 <function id="GetThreadCpuTimerInfo" num="136">
10336 <synopsis>Get Thread CPU Timer Information</synopsis>
10337 <description>
10338 Get information about the
10339 <functionlink id="GetThreadCpuTime"/> timer.
10340 The fields of the <datalink id="jvmtiTimerInfo"/> structure
10341 are filled in with details about the timer.
10342 This information is specific to the platform and the implementation of
10343 <functionlink id="GetThreadCpuTime"/> and thus
10344 does not vary by thread nor does it vary
10345 during a particular invocation of the VM.
10346 <p/>
10347 Note that the implementations of <functionlink id="GetCurrentThreadCpuTime"/>
10348 and <functionlink id="GetThreadCpuTime"/> may differ, and thus the values
10349 returned by <functionlink id="GetCurrentThreadCpuTimerInfo"/>
10350 and <code>GetThreadCpuTimerInfo</code>
10351 may differ -- see <functionlink id="GetCurrentThreadCpuTime"/> for more information.
10352 </description>
10353 <origin>new</origin>
10354 <capabilities>
10355 <required id="can_get_thread_cpu_time">
10356 Can get thread CPU time.
10357 </required>
10358 </capabilities>
10359 <parameters>
10360 <param id="info_ptr">
10361 <outptr><struct>jvmtiTimerInfo</struct></outptr>
10362 <description>
10363 On return, filled with information describing the time
10364 returned by <functionlink id="GetThreadCpuTime"/>.
10365 </description>
10366 </param>
10367 </parameters>
10368 <errors>
10369 </errors>
10370 </function>
10371
10372 <function id="GetThreadCpuTime" num="137">
10373 <synopsis>Get Thread CPU Time</synopsis>
10374 <description>
10375 Return the CPU time utilized by the specified thread.
10376 <p/>
10377 Get information about this timer with
10378 <functionlink id="GetThreadCpuTimerInfo"/>.
10379 </description>
10380 <origin>new</origin>
10381 <capabilities>
10382 <required id="can_get_thread_cpu_time">
10383 Can get thread CPU time.
10384 <p/>
10385 If this capability is enabled after threads have started,
10386 the implementation may choose any time up
10387 to and including the time that the capability is enabled
10388 as the point where CPU time collection starts.
10389 </required>
10390 </capabilities>
10391 <parameters>
10392 <param id="thread">
10393 <jthread null="current"/>
10394 <description>
10395 The thread to query.
10396 </description>
10397 </param>
10398 <param id="nanos_ptr">
10399 <outptr><jlong/></outptr>
10400 <description>
10401 On return, points to the CPU time used by the specified thread
10402 in nanoseconds.
10403 This is an unsigned value. If tested or printed as a jlong (signed value)
10404 it may appear to be a negative number.
10405 </description>
10406 </param>
10407 </parameters>
10408 <errors>
10409 </errors>
10410 </function>
10411
10412 <function id="GetTimerInfo" phase="any" callbacksafe="safe" num="138">
10413 <synopsis>Get Timer Information</synopsis>
10414 <description>
10415 Get information about the
10416 <functionlink id="GetTime"/> timer.
10417 The fields of the <datalink id="jvmtiTimerInfo"/> structure
10418 are filled in with details about the timer.
10419 This information will not change during a particular invocation of the VM.
10420 </description>
10421 <origin>new</origin>
10422 <capabilities>
10423 </capabilities>
10424 <parameters>
10425 <param id="info_ptr">
10426 <outptr><struct>jvmtiTimerInfo</struct></outptr>
10427 <description>
10428 On return, filled with information describing the time
10429 returned by <functionlink id="GetTime"/>.
10430 </description>
10431 </param>
10432 </parameters>
10433 <errors>
10434 </errors>
10435 </function>
10436
10437 <function id="GetTime" phase="any" callbacksafe="safe" num="139">
10438 <synopsis>Get Time</synopsis>
10439 <description>
10440 Return the current value of the system timer, in nanoseconds.
10441 <p/>
10442 The value returned represents nanoseconds since some fixed but
10443 arbitrary time (perhaps in the future, so values may be
10444 negative). This function provides nanosecond precision, but not
10445 necessarily nanosecond accuracy. No guarantees are made about
10446 how frequently values change.
10447 <p/>
10448 Get information about this timer with
10449 <functionlink id="GetTimerInfo"/>.
10450 </description>
10451 <origin>new</origin>
10452 <capabilities>
10453 </capabilities>
10454 <parameters>
10455 <param id="nanos_ptr">
10456 <outptr><jlong/></outptr>
10457 <description>
10458 On return, points to the time in nanoseconds.
10459 This is an unsigned value. If tested or printed as a jlong (signed value)
10460 it may appear to be a negative number.
10461 </description>
10462 </param>
10463 </parameters>
10464 <errors>
10465 </errors>
10466 </function>
10467
10468 <function id="GetAvailableProcessors" phase="any" num="144">
10469 <synopsis>Get Available Processors</synopsis>
10470 <description>
10471 Returns the number of processors available to the Java virtual machine.
10472 <p/>
10473 This value may change during a particular invocation of the virtual machine.
10474 Applications that are sensitive to the number of available processors should
10475 therefore occasionally poll this property.
10476 </description>
10477 <origin>new</origin>
10478 <capabilities>
10479 </capabilities>
10480 <parameters>
10481 <param id="processor_count_ptr">
10482 <outptr><jint/></outptr>
10483 <description>
10484 On return, points to the maximum number of processors available to the
10485 virtual machine; never smaller than one.
10486 </description>
10487 </param>
10488 </parameters>
10489 <errors>
10490 </errors>
10491 </function>
10492
10493 </category>
10494
10495
10496 <category id="classLoaderSearch" label="Class Loader Search">
10497
10498 <intro>
10499 These functions allow the agent to add to the locations that a class loader searches for a class.
10500 This is useful for installing instrumentation under the correct class loader.
10501 </intro>
10502
10503 <function id="AddToBootstrapClassLoaderSearch" jkernel="yes" phase="onload" num="149">
10504 <synopsis>Add To Bootstrap Class Loader Search</synopsis>
10505 <description>
10506 This function can be used to cause instrumentation classes to be defined by the
10507 bootstrap class loader. See <vmspec chapter="5.3.1"/>.
10508 After the bootstrap
10509 class loader unsuccessfully searches for a class, the specified platform-dependent
10510 search path <paramlink id="segment"/> will be searched as well. Only one segment may be specified in
10511 the <paramlink id="segment"/>. This function may be called multiple times to add multiple segments,
10512 the segments will be searched in the order that this function was called.
10513 <p/>
10514 In the <code>OnLoad</code> phase the function may be used to specify any platform-dependent
10515 search path segment to be searched after the bootstrap class loader unsuccessfully searches
10516 for a class. The segment is typically a directory or JAR file.
10517 <p/>
10518 In the live phase the <paramlink id="segment"/> may be used to specify any platform-dependent
10519 path to a <externallink id="http://docs.oracle.com/javase/7/docs/technotes/guides/jar/jar.html">
10520 JAR file</externallink>. The agent should take care that the JAR file does not
10521 contain any classes or resources other than those to be defined by the bootstrap
10522 class loader for the purposes of instrumentation.
10523 <p/>
10524 <vmspec/> specifies that a subsequent attempt to resolve a symbolic
10525 reference that the Java virtual machine has previously unsuccessfully attempted
10526 to resolve always fails with the same error that was thrown as a result of the
10527 initial resolution attempt. Consequently, if the JAR file contains an entry
10528 that corresponds to a class for which the Java virtual machine has
10529 unsuccessfully attempted to resolve a reference, then subsequent attempts to
10530 resolve that reference will fail with the same error as the initial attempt.
10531 </description>
10532 <origin>new</origin>
10533 <capabilities>
10534 </capabilities>
10535 <parameters>
10536 <param id="segment">
10537 <inbuf><char/></inbuf>
10538 <description>
10539 The platform-dependent search path segment, encoded as a
10540 <internallink id="mUTF">modified UTF-8</internallink> string.
10541 </description>
10542 </param>
10543 </parameters>
10544 <errors>
10545 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
10546 <paramlink id="segment"/> is an invalid path. In the live phase, anything other than an
10547 existing JAR file is an invalid path.
10548 </error>
10549 </errors>
10550 </function>
10551
10552 <function id="AddToSystemClassLoaderSearch" jkernel="yes" phase="onload" num="151" since="1.1">
10553 <synopsis>Add To System Class Loader Search</synopsis>
10554 <description>
10555 This function can be used to cause instrumentation classes to be
10556 defined by the system class loader. See <vmspec chapter="5.3.2"/>.
10557 After the class loader unsuccessfully searches for a class, the specified platform-dependent search
10558 path <paramlink id="segment"/> will be searched as well. Only one segment may be specified in the
10559 <paramlink id="segment"/>. This function may be called multiple times to add multiple segments, the
10560 segments will be searched in the order that this function was called.
10561 <p/>
10562 In the <code>OnLoad</code> phase the function may be used to specify any platform-dependent
10563 search path segment to be searched after the system class loader unsuccessfully searches
10564 for a class. The segment is typically a directory or JAR file.
10565 <p/>
10566 In the live phase the <paramlink id="segment"/> is a platform-dependent path to a <externallink
10567 id="http://docs.oracle.com/javase/7/docs/technotes/guides/jar/jar.html">JAR file</externallink> to be
10568 searched after the system class loader unsuccessfully searches for a class. The agent should
10569 take care that the JAR file does not contain any classes or resources other than those to be
10570 defined by the system class loader for the purposes of instrumentation.
10571 <p/>
10572 In the live phase the system class loader supports adding a JAR file to be searched if
10573 the system class loader implements a method name <code>appendToClassPathForInstrumentation</code>
10574 which takes a single parameter of type <code>java.lang.String</code>. The method is not required
10575 to have <code>public</code> access.
10576 <p/>
10577 <vmspec/> specifies that a subsequent attempt to resolve a symbolic
10578 reference that the Java virtual machine has previously unsuccessfully attempted
10579 to resolve always fails with the same error that was thrown as a result of the
10580 initial resolution attempt. Consequently, if the JAR file contains an entry
10581 that corresponds to a class for which the Java virtual machine has
10582 unsuccessfully attempted to resolve a reference, then subsequent attempts to
10583 resolve that reference will fail with the same error as the initial attempt.
10584 </description>
10585 <origin>new</origin>
10586 <capabilities>
10587 </capabilities>
10588 <parameters>
10589 <param id="segment">
10590 <inbuf><char/></inbuf>
10591 <description>
10592 The platform-dependent search path segment, encoded as a
10593 <internallink id="mUTF">modified UTF-8</internallink> string.
10594 </description>
10595 </param>
10596 </parameters>
10597 <errors>
10598 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
10599 <paramlink id="segment"/> is an invalid path. In the live phase, anything other than an
10600 existing JAR file is an invalid path.
10601 </error>
10602 <error id="JVMTI_ERROR_CLASS_LOADER_UNSUPPORTED">
10603 Operation not supported by the system class loader.
10604 </error>
10605 </errors>
10606 </function>
10607
10608 </category>
10609
10610
10611 <category id="props" label="System Properties">
10612
10613 <intro>
10614 These functions get and set system properties.
10615 </intro>
10616
10617 <function id="GetSystemProperties" phase="onload" num="130">
10618 <synopsis>Get System Properties</synopsis>
10619 <description>
10620 The list of VM system property keys which may be used with
10621 <functionlink id="GetSystemProperty"/> is returned.
10622 It is strongly recommended that virtual machines provide the
10623 following property keys:
10624 <ul>
10625 <li><code>java.vm.vendor</code></li>
10626 <li><code>java.vm.version</code></li>
10627 <li><code>java.vm.name</code></li>
10628 <li><code>java.vm.info</code></li>
10629 <li><code>java.library.path</code></li>
10630 <li><code>java.class.path</code></li>
10631 </ul>
10632 Provides access to system properties defined by and used
10633 by the VM.
10634 Properties set on the command-line are included.
10635 This allows getting and setting of these properties
10636 before the VM even begins executing bytecodes.
10637 Since this is a VM view of system properties, the set of available
10638 properties will usually be different than that
10639 in <code>java.lang.System.getProperties</code>.
10640 JNI method invocation may be used to access
10641 <code>java.lang.System.getProperties</code>.
10642 <p/>
10643 The set of properties may grow during execution.
10644 </description>
10645 <origin>new</origin>
10646 <capabilities>
10647 </capabilities>
10648 <parameters>
10649 <param id="count_ptr">
10650 <outptr><jint/></outptr>
10651 <description>
10652 On return, points to the number of property keys returned.
10653 </description>
10654 </param>
10655 <param id="property_ptr">
10656 <allocallocbuf outcount="count_ptr"><char/></allocallocbuf>
10657 <description>
10658 On return, points to an array of property keys, encoded as
10659 <internallink id="mUTF">modified UTF-8</internallink> strings.
10660 </description>
10661 </param>
10662 </parameters>
10663 <errors>
10664 </errors>
10665 </function>
10666
10667 <function id="GetSystemProperty" phase="onload" num="131">
10668 <synopsis>Get System Property</synopsis>
10669 <description>
10670 Return a VM system property value given the property key.
10671 <p/>
10672 The function <functionlink id="GetSystemProperties"/>
10673 returns the set of property keys which may be used.
10674 The properties which can be retrieved may grow during
10675 execution.
10676 <p/>
10677 Since this is a VM view of system properties, the values
10678 of properties may differ from that returned by
10679 <code>java.lang.System.getProperty(String)</code>.
10680 A typical VM might copy the values of the VM system
10681 properties into the <code>Properties</code> held by
10682 <code>java.lang.System</code> during the initialization
10683 of that class. Thereafter any changes to the VM system
10684 properties (with <functionlink id="SetSystemProperty"/>)
10685 or the <code>java.lang.System</code> system properties
10686 (with <code>java.lang.System.setProperty(String,String)</code>)
10687 would cause the values to diverge.
10688 JNI method invocation may be used to access
10689 <code>java.lang.System.getProperty(String)</code>.
10690 </description>
10691 <origin>new</origin>
10692 <capabilities>
10693 </capabilities>
10694 <parameters>
10695 <param id="property">
10696 <inbuf><char/></inbuf>
10697 <description>
10698 The key of the property to retrieve, encoded as a
10699 <internallink id="mUTF">modified UTF-8</internallink> string.
10700 </description>
10701 </param>
10702 <param id="value_ptr">
10703 <allocbuf><char/></allocbuf>
10704 <description>
10705 On return, points to the property value, encoded as a
10706 <internallink id="mUTF">modified UTF-8</internallink> string.
10707 </description>
10708 </param>
10709 </parameters>
10710 <errors>
10711 <error id="JVMTI_ERROR_NOT_AVAILABLE">
10712 This property is not available.
10713 Use <functionlink id="GetSystemProperties"/> to find available properties.
10714 </error>
10715 </errors>
10716 </function>
10717
10718 <function id="SetSystemProperty" phase="onloadOnly" num="132">
10719 <synopsis>Set System Property</synopsis>
10720 <description>
10721 Set a VM system property value.
10722 <p/>
10723 The function <functionlink id="GetSystemProperties"/>
10724 returns the set of property keys, some of these may be settable.
10725 See <functionlink id="GetSystemProperty"/>.
10726 </description>
10727 <origin>new</origin>
10728 <capabilities>
10729 </capabilities>
10730 <parameters>
10731 <param id="property">
10732 <inbuf><char/></inbuf>
10733 <description>
10734 The key of the property, encoded as a
10735 <internallink id="mUTF">modified UTF-8</internallink> string.
10736 </description>
10737 </param>
10738 <param id="value_ptr">
10739 <inbuf>
10740 <char/>
10741 <nullok>
10742 do not set the value, but return <errorlink id="JVMTI_ERROR_NOT_AVAILABLE"/>
10743 if the property is not writeable
10744 </nullok>
10745 </inbuf>
10746 <description>
10747 The property value to set, encoded as a
10748 <internallink id="mUTF">modified UTF-8</internallink> string.
10749 </description>
10750 </param>
10751 </parameters>
10752 <errors>
10753 <error id="JVMTI_ERROR_NOT_AVAILABLE">
10754 This property is not available or is not writeable.
10755 </error>
10756 </errors>
10757 </function>
10758
10759 </category>
10760
10761 <category id="general" label="General">
10762
10763 <intro>
10764 </intro>
10765
10766 <function id="GetPhase" jkernel="yes" phase="any" num="133">
10767 <synopsis>Get Phase</synopsis>
10768 <description>
10769 Return the current phase of VM execution.
10770 The phases proceed in sequence:
10771 <constants id="jvmtiPhase" label="Phases of execution" kind="enum">
10772 <constant id="JVMTI_PHASE_ONLOAD" num="1">
10773 <code>OnLoad</code> phase: while in the
10774 <internallink id="onload"><code>Agent_OnLoad</code></internallink>
10775 or, for statically linked agents, the <internallink id="onload">
10776 <code>Agent_OnLoad_<agent-lib-name>
10777 </code></internallink> function.
10778 </constant>
10779 <constant id="JVMTI_PHASE_PRIMORDIAL" num="2">
10780 Primordial phase: between return from <code>Agent_OnLoad</code>
10781 or <code>Agent_OnLoad_<agent-lib-name></code> and the
10782 <code>VMStart</code> event.
10783 </constant>
10784 <constant id="JVMTI_PHASE_START" num="6">
10785 Start phase: when the <eventlink id="VMStart"><code>VMStart</code></eventlink> event
10786 is sent and until the <code>VMInit</code> event is sent.
10787 </constant>
10788 <constant id="JVMTI_PHASE_LIVE" num="4">
10789 Live phase: when the <eventlink id="VMInit"><code>VMInit</code></eventlink> event is sent
10790 and until the <eventlink id="VMDeath"></eventlink> event returns.
10791 </constant>
10792 <constant id="JVMTI_PHASE_DEAD" num="8">
10793 Dead phase: after the <eventlink id="VMDeath"></eventlink> event returns or after
10794 start-up failure.
10795 </constant>
10796 </constants>
10797 In the case of start-up failure the VM will proceed directly to the dead
10798 phase skipping intermediate phases and neither a <code>VMInit</code> nor
10799 <code>VMDeath</code> event will be sent.
10800 <p/>
10801 Most <jvmti/> functions operate only in the live phase.
10802 The following functions operate in either the <code>OnLoad</code> or live phases:
10803 <functionphaselist phase="onload"/>
10804 The following functions operate in only the <code>OnLoad</code> phase:
10805 <functionphaselist phase="onloadOnly"/>
10806 The following functions operate in the start or live phases:
10807 <functionphaselist phase="start"/>
10808 The following functions operate in any phase:
10809 <functionphaselist phase="any"/>
10810 JNI functions (except the Invocation API) must only be used in the start or live phases.
10811 <p/>
10812 Most <jvmti/> events are sent only in the live phase.
10813 The following events operate in others phases:
10814 <eventphaselist phase="start"/>
10815 <eventphaselist phase="any"/>
10816 </description>
10817 <origin>new</origin>
10818 <capabilities>
10819 </capabilities>
10820 <parameters>
10821 <param id="phase_ptr">
10822 <outptr><enum>jvmtiPhase</enum></outptr>
10823 <description>
10824 On return, points to the phase.
10825 </description>
10826 </param>
10827 </parameters>
10828 <errors>
10829 </errors>
10830 </function>
10831
10832 <function id="DisposeEnvironment" jkernel="yes" phase="any" num="127">
10833 <synopsis>Dispose Environment</synopsis>
10834 <description>
10835 Shutdown a <jvmti/> connection created with JNI <code>GetEnv</code>
10836 (see <internallink id="environments"><jvmti/> Environments</internallink>).
10837 Dispose of any resources held by the environment.
10838 <issue>
10839 What resources are reclaimed? What is undone?
10840 Breakpoints,watchpoints removed?
10841 </issue>
10842 Threads suspended by this environment are not resumed by this call,
10843 this must be done explicitly by the agent.
10844 Memory allocated by this environment via calls to <jvmti/> functions
10845 is not released, this can be done explicitly by the agent
10846 by calling <functionlink id="Deallocate"/>.
10847 Raw monitors created by this environment are not destroyed,
10848 this can be done explicitly by the agent
10849 by calling <functionlink id="DestroyRawMonitor"/>.
10850 The state of threads waiting on raw monitors created by this environment
10851 are not affected.
10852 <p/>
10853 Any <functionlink id="SetNativeMethodPrefix">native method
10854 prefixes</functionlink> for this environment will be unset;
10855 the agent must remove any prefixed native methods before
10856 dispose is called.
10857 <p/>
10858 Any <internallink id="capability">capabilities</internallink>
10859 held by this environment are relinquished.
10860 <p/>
10861 Events enabled by this environment will no longer be sent, however
10862 event handlers currently running will continue to run. Caution must
10863 be exercised in the design of event handlers whose environment may
10864 be disposed and thus become invalid during their execution.
10865 <p/>
10866 This environment may not be used after this call.
10867 This call returns to the caller.
10868 </description>
10869 <origin>new</origin>
10870 <capabilities>
10871 </capabilities>
10872 <parameters>
10873 </parameters>
10874 <errors>
10875 </errors>
10876 </function>
10877
10878 <function id="SetEnvironmentLocalStorage" jkernel="yes" phase="any" callbacksafe="safe" impl="innative notrace" num="148">
10879 <synopsis>Set Environment Local Storage</synopsis>
10880 <description>
10881 The VM stores a pointer value associated with each environment.
10882 This pointer value is called <i>environment-local storage</i>.
10883 This value is <code>NULL</code> unless set with this function.
10884 Agents can allocate memory in which they store environment specific
10885 information. By setting environment-local storage it can then be
10886 accessed with
10887 <functionlink id="GetEnvironmentLocalStorage"></functionlink>.
10888 <p/>
10889 Called by the agent to set the value of the <jvmti/>
10890 environment-local storage. <jvmti/> supplies to the agent a pointer-size
10891 environment-local storage that can be used to record per-environment
10892 information.
10893 </description>
10894 <origin>new</origin>
10895 <capabilities>
10896 </capabilities>
10897 <parameters>
10898 <param id="data">
10899 <inbuf>
10900 <void/>
10901 <nullok>value is set to <code>NULL</code></nullok>
10902 </inbuf>
10903 <description>
10904 The value to be entered into the environment-local storage.
10905 </description>
10906 </param>
10907 </parameters>
10908 <errors>
10909 </errors>
10910 </function>
10911
10912 <function id="GetEnvironmentLocalStorage" jkernel="yes" phase="any" callbacksafe="safe" impl="innative notrace" num="147">
10913 <synopsis>Get Environment Local Storage</synopsis>
10914 <description>
10915 Called by the agent to get the value of the <jvmti/> environment-local
10916 storage.
10917 </description>
10918 <origin>new</origin>
10919 <capabilities>
10920 </capabilities>
10921 <parameters>
10922 <param id="data_ptr">
10923 <agentbuf><void/></agentbuf>
10924 <description>
10925 Pointer through which the value of the environment local
10926 storage is returned.
10927 If environment-local storage has not been set with
10928 <functionlink id="SetEnvironmentLocalStorage"></functionlink> returned
10929 pointer is <code>NULL</code>.
10930 </description>
10931 </param>
10932 </parameters>
10933 <errors>
10934 </errors>
10935 </function>
10936
10937 <function id="GetVersionNumber" jkernel="yes" phase="any" num="88">
10938 <synopsis>Get Version Number</synopsis>
10939 <description>
10940 Return the <jvmti/> version via <code>version_ptr</code>.
10941 The return value is the version identifier.
10942 The version identifier includes major, minor and micro
10943 version as well as the interface type.
10944 <constants id="jvmtiVersionInterfaceTypes" label="Version Interface Types" kind="bits">
10945 <constant id="JVMTI_VERSION_INTERFACE_JNI" num="0x00000000">
10946 Value of <code>JVMTI_VERSION_MASK_INTERFACE_TYPE</code> for JNI.
10947 </constant>
10948 <constant id="JVMTI_VERSION_INTERFACE_JVMTI" num="0x30000000">
10949 Value of <code>JVMTI_VERSION_MASK_INTERFACE_TYPE</code> for <jvmti/>.
10950 </constant>
10951 </constants>
10952 <constants id="jvmtiVersionMasks" label="Version Masks" kind="bits">
10953 <constant id="JVMTI_VERSION_MASK_INTERFACE_TYPE" num="0x70000000">
10954 Mask to extract interface type.
10955 The value of the version returned by this function masked with
10956 <code>JVMTI_VERSION_MASK_INTERFACE_TYPE</code> is always
10957 <code>JVMTI_VERSION_INTERFACE_JVMTI</code>
10958 since this is a <jvmti/> function.
10959 </constant>
10960 <constant id="JVMTI_VERSION_MASK_MAJOR" num="0x0FFF0000">
10961 Mask to extract major version number.
10962 </constant>
10963 <constant id="JVMTI_VERSION_MASK_MINOR" num="0x0000FF00">
10964 Mask to extract minor version number.
10965 </constant>
10966 <constant id="JVMTI_VERSION_MASK_MICRO" num="0x000000FF">
10967 Mask to extract micro version number.
10968 </constant>
10969 </constants>
10970 <constants id="jvmtiVersionShifts" label="Version Shifts" kind="bits">
10971 <constant id="JVMTI_VERSION_SHIFT_MAJOR" num="16">
10972 Shift to extract major version number.
10973 </constant>
10974 <constant id="JVMTI_VERSION_SHIFT_MINOR" num="8">
10975 Shift to extract minor version number.
10976 </constant>
10977 <constant id="JVMTI_VERSION_SHIFT_MICRO" num="0">
10978 Shift to extract micro version number.
10979 </constant>
10980 </constants>
10981 </description>
10982 <origin>jvmdi</origin>
10983 <capabilities>
10984 </capabilities>
10985 <parameters>
10986 <param id="version_ptr">
10987 <outptr><jint/></outptr>
10988 <description>
10989 On return, points to the <jvmti/> version.
10990 </description>
10991 </param>
10992 </parameters>
10993 <errors>
10994 </errors>
10995 </function>
10996
10997
10998 <function id="GetErrorName" phase="any" num="128">
10999 <synopsis>Get Error Name</synopsis>
11000 <description>
11001 Return the symbolic name for an
11002 <internallink id="ErrorSection">error code</internallink>.
11003 <p/>
11004 For example
11005 <code>GetErrorName(env, JVMTI_ERROR_NONE, &err_name)</code>
11006 would return in <code>err_name</code> the string
11007 <code>"JVMTI_ERROR_NONE"</code>.
11008 </description>
11009 <origin>new</origin>
11010 <capabilities>
11011 </capabilities>
11012 <parameters>
11013 <param id="error">
11014 <enum>jvmtiError</enum>
11015 <description>
11016 The error code.
11017 </description>
11018 </param>
11019 <param id="name_ptr">
11020 <allocbuf><char/></allocbuf>
11021 <description>
11022 On return, points to the error name.
11023 The name is encoded as a
11024 <internallink id="mUTF">modified UTF-8</internallink> string,
11025 but is restricted to the ASCII subset.
11026 </description>
11027 </param>
11028 </parameters>
11029 <errors>
11030 </errors>
11031 </function>
11032
11033 <function id="SetVerboseFlag" phase="any" num="150">
11034 <synopsis>Set Verbose Flag</synopsis>
11035 <description>
11036 <constants id="jvmtiVerboseFlag" label="Verbose Flag Enumeration" kind="enum">
11037 <constant id="JVMTI_VERBOSE_OTHER" num="0">
11038 Verbose output other than the below.
11039 </constant>
11040 <constant id="JVMTI_VERBOSE_GC" num="1">
11041 Verbose garbage collector output, like that specified with <code>-verbose:gc</code>.
11042 </constant>
11043 <constant id="JVMTI_VERBOSE_CLASS" num="2">
11044 Verbose class loading output, like that specified with <code>-verbose:class</code>.
11045 </constant>
11046 <constant id="JVMTI_VERBOSE_JNI" num="4">
11047 Verbose JNI output, like that specified with <code>-verbose:jni</code>.
11048 </constant>
11049 </constants>
11050 Control verbose output.
11051 This is the output which typically is sent to <code>stderr</code>.
11052 </description>
11053 <origin>new</origin>
11054 <capabilities>
11055 </capabilities>
11056 <parameters>
11057 <param id="flag">
11058 <enum>jvmtiVerboseFlag</enum>
11059 <description>
11060 Which verbose flag to set.
11061 </description>
11062 </param>
11063 <param id="value">
11064 <jboolean/>
11065 <description>
11066 New value of the flag.
11067 </description>
11068 </param>
11069 </parameters>
11070 <errors>
11071 </errors>
11072 </function>
11073
11074
11075 <function id="GetJLocationFormat" phase="any" num="129">
11076 <synopsis>Get JLocation Format</synopsis>
11077 <description>
11078 Although the greatest functionality is achieved with location information
11079 referencing the virtual machine bytecode index, the definition of
11080 <code>jlocation</code> has intentionally been left unconstrained to allow VM
11081 implementations that do not have this information.
11082 <p/>
11083 This function describes the representation of <code>jlocation</code> used in this VM.
11084 If the returned format is <datalink id="JVMTI_JLOCATION_JVMBCI"></datalink>,
11085 <code>jlocation</code>s can
11086 be used as in indices into the array returned by
11087 <functionlink id="GetBytecodes"></functionlink>.
11088 <constants id="jvmtiJlocationFormat" label="JLocation Format Enumeration" kind="enum">
11089 <constant id="JVMTI_JLOCATION_JVMBCI" num="1">
11090 <code>jlocation</code> values represent virtual machine
11091 bytecode indices--that is, offsets into the
11092 virtual machine code for a method.
11093 </constant>
11094 <constant id="JVMTI_JLOCATION_MACHINEPC" num="2">
11095 <code>jlocation</code> values represent native machine
11096 program counter values.
11097 </constant>
11098 <constant id="JVMTI_JLOCATION_OTHER" num="0">
11099 <code>jlocation</code> values have some other representation.
11100 </constant>
11101 </constants>
11102 </description>
11103 <origin>new</origin>
11104 <capabilities>
11105 </capabilities>
11106 <parameters>
11107 <param id="format_ptr">
11108 <outptr><enum>jvmtiJlocationFormat</enum></outptr>
11109 <description>
11110 On return, points to the format identifier for <code>jlocation</code> values.
11111 </description>
11112 </param>
11113 </parameters>
11114 <errors>
11115 </errors>
11116 </function>
11117
11118 </category>
11119
11120 </functionsection>
11121
11122 <errorsection label="Error Reference">
11123 <intro>
11124 Every <jvmti/> function returns a <b><code>jvmtiError</code></b> error code.
11125 <p/>
11126 It is the responsibility of the agent to call <jvmti/> functions with
11127 valid parameters and in the proper context (calling thread is attached,
11128 phase is correct, etc.).
11129 Detecting some error conditions may be difficult, inefficient, or
11130 impossible for an implementation.
11131 The errors listed in
11132 <internallink id="reqerrors">Function Specific Required Errors</internallink>
11133 must be detected by the implementation.
11134 All other errors represent the recommended response to the error
11135 condition.
11136 </intro>
11137
11138 <errorcategory id="universal-error" label="Universal Errors">
11139 <intro>
11140 The following errors may be returned by any function
11141 </intro>
11142
11143 <errorid id="JVMTI_ERROR_NONE" num="0">
11144 No error has occurred. This is the error code that is returned
11145 on successful completion of the function.
11146 </errorid>
11147 <errorid id="JVMTI_ERROR_NULL_POINTER" num="100">
11148 Pointer is unexpectedly <code>NULL</code>.
11149 </errorid>
11150 <errorid id="JVMTI_ERROR_OUT_OF_MEMORY" num="110">
11151 The function attempted to allocate memory and no more memory was
11152 available for allocation.
11153 </errorid>
11154 <errorid id="JVMTI_ERROR_ACCESS_DENIED" num="111">
11155 The desired functionality has not been enabled in this virtual machine.
11156 </errorid>
11157 <errorid id="JVMTI_ERROR_UNATTACHED_THREAD" num="115">
11158 The thread being used to call this function is not attached
11159 to the virtual machine. Calls must be made from attached threads.
11160 See <code>AttachCurrentThread</code> in the JNI invocation API.
11161 </errorid>
11162 <errorid id="JVMTI_ERROR_INVALID_ENVIRONMENT" num="116">
11163 The <jvmti/> environment provided is no longer connected or is
11164 not an environment.
11165 </errorid>
11166 <errorid id="JVMTI_ERROR_WRONG_PHASE" num="112">
11167 The desired functionality is not available in the current
11168 <functionlink id="GetPhase">phase</functionlink>.
11169 Always returned if the virtual machine has completed running.
11170 </errorid>
11171 <errorid id="JVMTI_ERROR_INTERNAL" num="113">
11172 An unexpected internal error has occurred.
11173 </errorid>
11174 </errorcategory>
11175
11176 <errorcategory id="reqerrors" label="Function Specific Required Errors">
11177 <intro>
11178 The following errors are returned by some <jvmti/> functions and must
11179 be returned by the implementation when the condition occurs.
11180 </intro>
11181
11182 <errorid id="JVMTI_ERROR_INVALID_PRIORITY" num="12">
11183 Invalid priority.
11184 </errorid>
11185 <errorid id="JVMTI_ERROR_THREAD_NOT_SUSPENDED" num="13">
11186 Thread was not suspended.
11187 </errorid>
11188 <errorid id="JVMTI_ERROR_THREAD_SUSPENDED" num="14">
11189 Thread already suspended.
11190 </errorid>
11191 <errorid id="JVMTI_ERROR_THREAD_NOT_ALIVE" num="15">
11192 This operation requires the thread to be alive--that is,
11193 it must be started and not yet have died.
11194 </errorid>
11195 <errorid id="JVMTI_ERROR_CLASS_NOT_PREPARED" num="22">
11196 The class has been loaded but not yet prepared.
11197 </errorid>
11198 <errorid id="JVMTI_ERROR_NO_MORE_FRAMES" num="31">
11199 There are no Java programming language or JNI stack frames at the specified depth.
11200 </errorid>
11201 <errorid id="JVMTI_ERROR_OPAQUE_FRAME" num="32">
11202 Information about the frame is not available (e.g. for native frames).
11203 </errorid>
11204 <errorid id="JVMTI_ERROR_DUPLICATE" num="40">
11205 Item already set.
11206 </errorid>
11207 <errorid id="JVMTI_ERROR_NOT_FOUND" num="41">
11208 Desired element (e.g. field or breakpoint) not found
11209 </errorid>
11210 <errorid id="JVMTI_ERROR_NOT_MONITOR_OWNER" num="51">
11211 This thread doesn't own the raw monitor.
11212 </errorid>
11213 <errorid id="JVMTI_ERROR_INTERRUPT" num="52">
11214 The call has been interrupted before completion.
11215 </errorid>
11216 <errorid id="JVMTI_ERROR_UNMODIFIABLE_CLASS" num="79">
11217 The class cannot be modified.
11218 </errorid>
11219 <errorid id="JVMTI_ERROR_NOT_AVAILABLE" num="98">
11220 The functionality is not available in this virtual machine.
11221 </errorid>
11222 <errorid id="JVMTI_ERROR_ABSENT_INFORMATION" num="101">
11223 The requested information is not available.
11224 </errorid>
11225 <errorid id="JVMTI_ERROR_INVALID_EVENT_TYPE" num="102">
11226 The specified event type ID is not recognized.
11227 </errorid>
11228 <errorid id="JVMTI_ERROR_NATIVE_METHOD" num="104">
11229 The requested information is not available for native method.
11230 </errorid>
11231 <errorid id="JVMTI_ERROR_CLASS_LOADER_UNSUPPORTED" num="106">
11232 The class loader does not support this operation.
11233 </errorid>
11234 </errorcategory>
11235
11236 <errorcategory id="function-specific-errors" label="Function Specific Agent Errors">
11237 <intro>
11238 The following errors are returned by some <jvmti/> functions.
11239 They are returned in the event of invalid parameters passed by the
11240 agent or usage in an invalid context.
11241 An implementation is not required to detect these errors.
11242 </intro>
11243
11244 <errorid id="JVMTI_ERROR_INVALID_THREAD" num="10">
11245 The passed thread is not a valid thread.
11246 </errorid>
11247 <errorid id="JVMTI_ERROR_INVALID_FIELDID" num="25">
11248 Invalid field.
11249 </errorid>
11250 <errorid id="JVMTI_ERROR_INVALID_METHODID" num="23">
11251 Invalid method.
11252 </errorid>
11253 <errorid id="JVMTI_ERROR_INVALID_LOCATION" num="24">
11254 Invalid location.
11255 </errorid>
11256 <errorid id="JVMTI_ERROR_INVALID_OBJECT" num="20">
11257 Invalid object.
11258 </errorid>
11259 <errorid id="JVMTI_ERROR_INVALID_CLASS" num="21">
11260 Invalid class.
11261 </errorid>
11262 <errorid id="JVMTI_ERROR_TYPE_MISMATCH" num="34">
11263 The variable is not an appropriate type for the function used.
11264 </errorid>
11265 <errorid id="JVMTI_ERROR_INVALID_SLOT" num="35">
11266 Invalid slot.
11267 </errorid>
11268 <errorid id="JVMTI_ERROR_MUST_POSSESS_CAPABILITY" num="99">
11269 The capability being used is false in this environment.
11270 </errorid>
11271 <errorid id="JVMTI_ERROR_INVALID_THREAD_GROUP" num="11">
11272 Thread group invalid.
11273 </errorid>
11274 <errorid id="JVMTI_ERROR_INVALID_MONITOR" num="50">
11275 Invalid raw monitor.
11276 </errorid>
11277 <errorid id="JVMTI_ERROR_ILLEGAL_ARGUMENT" num="103">
11278 Illegal argument.
11279 </errorid>
11280 <errorid id="JVMTI_ERROR_INVALID_TYPESTATE" num="65">
11281 The state of the thread has been modified, and is now inconsistent.
11282 </errorid>
11283 <errorid id="JVMTI_ERROR_UNSUPPORTED_VERSION" num="68">
11284 A new class file has a version number not supported by this VM.
11285 </errorid>
11286 <errorid id="JVMTI_ERROR_INVALID_CLASS_FORMAT" num="60">
11287 A new class file is malformed (the VM would return a <code>ClassFormatError</code>).
11288 </errorid>
11289 <errorid id="JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION" num="61">
11290 The new class file definitions would lead to a circular
11291 definition (the VM would return a <code>ClassCircularityError</code>).
11292 </errorid>
11293 <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED" num="63">
11294 A new class file would require adding a method.
11295 </errorid>
11296 <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED" num="64">
11297 A new class version changes a field.
11298 </errorid>
11299 <errorid id="JVMTI_ERROR_FAILS_VERIFICATION" num="62">
11300 The class bytes fail verification.
11301 </errorid>
11302 <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED" num="66">
11303 A direct superclass is different for the new class
11304 version, or the set of directly implemented
11305 interfaces is different.
11306 </errorid>
11307 <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED" num="67">
11308 A new class version does not declare a method
11309 declared in the old class version.
11310 </errorid>
11311 <errorid id="JVMTI_ERROR_NAMES_DONT_MATCH" num="69">
11312 The class name defined in the new class file is
11313 different from the name in the old class object.
11314 </errorid>
11315 <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED" num="70">
11316 A new class version has different modifiers.
11317 </errorid>
11318 <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED" num="71">
11319 A method in the new class version has different modifiers
11320 than its counterpart in the old class version.
11321 </errorid>
11322 </errorcategory>
11323 </errorsection>
11324
11325 <eventsection label="Events">
11326 <intro label="Handling Events" id="eventIntro">
11327 Agents can be informed of many events that occur in application
11328 programs.
11329 <p/>
11330 To handle events, designate a set of callback functions with
11331 <functionlink id="SetEventCallbacks"></functionlink>.
11332 For each event the corresponding callback function will be
11333 called.
11334 Arguments to the callback function provide additional
11335 information about the event.
11336 <p/>
11337 The callback function is usually called from within an application
11338 thread. The <jvmti/> implementation does not
11339 queue events in any way. This means
11340 that event callback functions must be written
11341 carefully. Here are some general guidelines. See
11342 the individual event descriptions for further
11343 suggestions.
11344 <p/>
11345 <ul>
11346 <li>Any exception thrown during the execution of an event callback can
11347 overwrite any current pending exception in the current application thread.
11348 Care must be taken to preserve a pending exception
11349 when an event callback makes a JNI call that might generate an exception.
11350 </li>
11351 <li>Event callback functions must be re-entrant. The <jvmti/> implementation does
11352 not queue events. If an agent needs to process events one at a time, it
11353 can use a raw monitor inside the
11354 event callback functions to serialize event processing.
11355 </li>
11356 <li>Event callback functions that execute JNI's FindClass function to load
11357 classes need to note that FindClass locates the class loader associated
11358 with the current native method. For the purposes of class loading, an
11359 event callback that includes a JNI environment as a parameter to the
11360 callback will treated as if it is a native call, where the native method
11361 is in the class of the event thread's current frame.
11362 </li>
11363 </ul>
11364 <p/>
11365 Some <jvmti/> events identify objects with JNI references.
11366 All references
11367 in <jvmti/> events are JNI local references and will become invalid
11368 after the event callback returns.
11369 Unless stated otherwise, memory referenced by pointers sent in event
11370 callbacks may not be referenced after the event callback returns.
11371 <p/>
11372 Except where stated otherwise, events are delivered on the thread
11373 that caused the event.
11374 Events are sent at the time they occur.
11375 The specification for each event includes the set of
11376 <functionlink id="GetPhase">phases</functionlink> in which it can be sent;
11377 if an event triggering activity occurs during another phase, no event
11378 is sent.
11379 <p/>
11380 A thread that generates an event does not change its execution status
11381 (for example, the event does not cause the thread to be suspended).
11382 If an agent wishes the event to result in suspension, then the agent
11383 is responsible for explicitly suspending the thread with
11384 <functionlink id="SuspendThread"></functionlink>.
11385 <p/>
11386 If an event is enabled in multiple environments, the event will be sent
11387 to each agent in the order that the environments were created.
11388 </intro>
11389
11390 <intro label="Enabling Events" id="enablingevents">
11391 All events are initially disabled. In order to receive any
11392 event:
11393 <ul>
11394 <li>
11395 If the event requires a capability, that capability must
11396 be added with
11397 <functionlink id="AddCapabilities"></functionlink>.
11398 </li>
11399 <li>
11400 A callback for the event must be set with
11401 <functionlink id="SetEventCallbacks"></functionlink>.
11402 </li>
11403 <li>
11404 The event must be enabled with
11405 <functionlink id="SetEventNotificationMode"></functionlink>.
11406 </li>
11407 </ul>
11408 </intro>
11409
11410 <intro label="Multiple Co-located Events" id="eventorder">
11411 In many situations it is possible for multiple events to occur
11412 at the same location in one thread. When this happens, all the events
11413 are reported through the event callbacks in the order specified in this section.
11414 <p/>
11415 If the current location is at the entry point of a method, the
11416 <eventlink id="MethodEntry"></eventlink> event is reported before
11417 any other event at the current location in the same thread.
11418 <p/>
11419 If an exception catch has been detected at the current location,
11420 either because it is the beginning of a catch clause or a native method
11421 that cleared a pending exception has returned, the
11422 <code>exceptionCatch</code> event is reported before
11423 any other event at the current location in the same thread.
11424 <p/>
11425 If a <code>singleStep</code> event or
11426 <code>breakpoint</code> event is triggered at the
11427 current location, the event is defined to occur
11428 immediately before the code at the current location is executed.
11429 These events are reported before any events which are triggered
11430 by the execution of code at the current location in the same
11431 thread (specifically:
11432 <code>exception</code>,
11433 <code>fieldAccess</code>, and
11434 <code>fieldModification</code>).
11435 If both a step and breakpoint event are triggered for the same thread and
11436 location, the step event is reported before the breakpoint event.
11437 <p/>
11438 If the current location is the exit point of a method (that is, the last
11439 location before returning to the caller), the
11440 <eventlink id="MethodExit"></eventlink> event and
11441 the <eventlink id="FramePop"></eventlink> event (if requested)
11442 are reported after all other events at the current location in the same
11443 thread. There is no specified ordering of these two events
11444 with respect to each other.
11445 <p/>
11446 Co-located events can be triggered during the processing of some other
11447 event by the agent at the same location in the same thread.
11448 If such an event, of type <i>y</i>, is triggered during the processing of
11449 an event of type <i>x</i>, and if <i>x</i>
11450 precedes <i>y</i> in the ordering specified above, the co-located event
11451 <i>y</i> is reported for the current thread and location. If <i>x</i> does not precede
11452 <i>y</i>, <i>y</i> is not reported for the current thread and location.
11453 For example, if a breakpoint is set at the current location
11454 during the processing of <eventlink id="SingleStep"></eventlink>,
11455 that breakpoint will be reported before the thread moves off the current
11456 location.
11457 <p/>The following events are never considered to be co-located with
11458 other events.
11459 <ul>
11460 <li><eventlink id="VMStart"></eventlink></li>
11461 <li><eventlink id="VMInit"></eventlink></li>
11462 <li><eventlink id="VMDeath"></eventlink></li>
11463 <li><eventlink id="ThreadStart"></eventlink></li>
11464 <li><eventlink id="ThreadEnd"></eventlink></li>
11465 <li><eventlink id="ClassLoad"></eventlink></li>
11466 <li><eventlink id="ClassPrepare"></eventlink></li>
11467 </ul>
11468 </intro>
11469
11470 <intro label="Event Callbacks" id="jvmtiEventCallbacks">
11471 The event callback structure below is used to specify the handler function
11472 for events. It is set with the
11473 <functionlink id="SetEventCallbacks"></functionlink> function.
11474 </intro>
11475
11476 <event label="Single Step"
11477 id="SingleStep" const="JVMTI_EVENT_SINGLE_STEP" filtered="thread" num="60">
11478 <description>
11479 Single step events allow the agent to trace thread execution
11480 at the finest granularity allowed by the VM. A single step event is
11481 generated whenever a thread reaches a new location.
11482 Typically, single step events represent the completion of one VM
11483 instruction as defined in <vmspec/>. However, some implementations
11484 may define locations differently. In any case the
11485 <code>method</code> and <code>location</code>
11486 parameters uniquely identify the current location and allow
11487 the mapping to source file and line number when that information is
11488 available.
11489 <p/>
11490 No single step events are generated from within native methods.
11491 </description>
11492 <origin>jvmdi</origin>
11493 <capabilities>
11494 <required id="can_generate_single_step_events"></required>
11495 </capabilities>
11496 <parameters>
11497 <param id="jni_env">
11498 <outptr>
11499 <struct>JNIEnv</struct>
11500 </outptr>
11501 <description>
11502 The JNI environment of the event (current) thread
11503 </description>
11504 </param>
11505 <param id="thread">
11506 <jthread/>
11507 <description>
11508 Thread about to execution a new instruction
11509 </description>
11510 </param>
11511 <param id="klass">
11512 <jclass method="method"/>
11513 <description>
11514 Class of the method about to execute a new instruction
11515 </description>
11516 </param>
11517 <param id="method">
11518 <jmethodID class="klass"/>
11519 <description>
11520 Method about to execute a new instruction
11521 </description>
11522 </param>
11523 <param id="location">
11524 <jlocation/>
11525 <description>
11526 Location of the new instruction
11527 </description>
11528 </param>
11529 </parameters>
11530 </event>
11531
11532 <event label="Breakpoint"
11533 id="Breakpoint" const="JVMTI_EVENT_BREAKPOINT" filtered="thread" num="62">
11534 <description>
11535 Breakpoint events are generated whenever a thread reaches a location
11536 designated as a breakpoint with <functionlink id="SetBreakpoint"></functionlink>.
11537 The <code>method</code> and <code>location</code>
11538 parameters uniquely identify the current location and allow
11539 the mapping to source file and line number when that information is
11540 available.
11541 </description>
11542 <origin>jvmdi</origin>
11543 <capabilities>
11544 <required id="can_generate_breakpoint_events"></required>
11545 </capabilities>
11546 <parameters>
11547 <param id="jni_env">
11548 <outptr>
11549 <struct>JNIEnv</struct>
11550 </outptr>
11551 <description>
11552 The JNI environment of the event (current) thread.
11553 </description>
11554 </param>
11555 <param id="thread">
11556 <jthread/>
11557 <description>
11558 Thread that hit the breakpoint
11559 </description>
11560 </param>
11561 <param id="klass">
11562 <jclass method="method"/>
11563 <description>
11564 Class of the method that hit the breakpoint
11565 </description>
11566 </param>
11567 <param id="method">
11568 <jmethodID class="klass"/>
11569 <description>
11570 Method that hit the breakpoint
11571 </description>
11572 </param>
11573 <param id="location">
11574 <jlocation/>
11575 <description>
11576 location of the breakpoint
11577 </description>
11578 </param>
11579 </parameters>
11580 </event>
11581
11582 <event label="Field Access"
11583 id="FieldAccess" const="JVMTI_EVENT_FIELD_ACCESS" filtered="thread" num="63">
11584 <description>
11585 Field access events are generated whenever a thread accesses
11586 a field that was designated as a watchpoint
11587 with <functionlink id="SetFieldAccessWatch"></functionlink>.
11588 The <code>method</code> and <code>location</code>
11589 parameters uniquely identify the current location and allow
11590 the mapping to source file and line number when that information is
11591 available.
11592 </description>
11593 <origin>jvmdi</origin>
11594 <capabilities>
11595 <required id="can_generate_field_access_events"></required>
11596 </capabilities>
11597 <parameters>
11598 <param id="jni_env">
11599 <outptr>
11600 <struct>JNIEnv</struct>
11601 </outptr>
11602 <description>
11603 The JNI environment of the event (current) thread
11604 </description>
11605 </param>
11606 <param id="thread">
11607 <jthread/>
11608 <description>
11609 Thread accessing the field
11610 </description>
11611 </param>
11612 <param id="klass">
11613 <jclass method="method"/>
11614 <description>
11615 Class of the method where the access is occurring
11616 </description>
11617 </param>
11618 <param id="method">
11619 <jmethodID class="klass"/>
11620 <description>
11621 Method where the access is occurring
11622 </description>
11623 </param>
11624 <param id="location">
11625 <jlocation/>
11626 <description>
11627 Location where the access is occurring
11628 </description>
11629 </param>
11630 <param id="field_klass">
11631 <jclass field="field"/>
11632 <description>
11633 Class of the field being accessed
11634 </description>
11635 </param>
11636 <param id="object">
11637 <jobject/>
11638 <description>
11639 Object with the field being accessed if the field is an
11640 instance field; <code>NULL</code> otherwise
11641 </description>
11642 </param>
11643 <param id="field">
11644 <jfieldID class="field_klass"/>
11645 <description>
11646 Field being accessed
11647 </description>
11648 </param>
11649 </parameters>
11650 </event>
11651
11652 <event label="Field Modification"
11653 id="FieldModification" const="JVMTI_EVENT_FIELD_MODIFICATION" filtered="thread" num="64">
11654 <description>
11655 Field modification events are generated whenever a thread modifies
11656 a field that was designated as a watchpoint
11657 with <functionlink id="SetFieldModificationWatch"></functionlink>.
11658 The <code>method</code> and <code>location</code>
11659 parameters uniquely identify the current location and allow
11660 the mapping to source file and line number when that information is
11661 available.
11662 </description>
11663 <origin>jvmdi</origin>
11664 <capabilities>
11665 <required id="can_generate_field_modification_events"></required>
11666 </capabilities>
11667 <parameters>
11668 <param id="jni_env">
11669 <outptr>
11670 <struct>JNIEnv</struct>
11671 </outptr>
11672 <description>
11673 The JNI environment of the event (current) thread
11674 </description>
11675 </param>
11676 <param id="thread">
11677 <jthread/>
11678 <description>
11679 Thread modifying the field
11680 </description>
11681 </param>
11682 <param id="klass">
11683 <jclass method="method"/>
11684 <description>
11685 Class of the method where the modification is occurring
11686 </description>
11687 </param>
11688 <param id="method">
11689 <jmethodID class="klass"/>
11690 <description>
11691 Method where the modification is occurring
11692 </description>
11693 </param>
11694 <param id="location">
11695 <jlocation/>
11696 <description>
11697 Location where the modification is occurring
11698 </description>
11699 </param>
11700 <param id="field_klass">
11701 <jclass field="field"/>
11702 <description>
11703 Class of the field being modified
11704 </description>
11705 </param>
11706 <param id="object">
11707 <jobject/>
11708 <description>
11709 Object with the field being modified if the field is an
11710 instance field; <code>NULL</code> otherwise
11711 </description>
11712 </param>
11713 <param id="field">
11714 <jfieldID class="field_klass"/>
11715 <description>
11716 Field being modified
11717 </description>
11718 </param>
11719 <param id="signature_type">
11720 <char/>
11721 <description>
11722 Signature type of the new value
11723 </description>
11724 </param>
11725 <param id="new_value">
11726 <jvalue/>
11727 <description>
11728 The new value
11729 </description>
11730 </param>
11731 </parameters>
11732 </event>
11733
11734 <event label="Frame Pop"
11735 id="FramePop" const="JVMTI_EVENT_FRAME_POP" filtered="thread" num="61">
11736 <description>
11737 Frame pop events are generated upon exit from a single method
11738 in a single frame as specified
11739 in a call to <functionlink id="NotifyFramePop"></functionlink>.
11740 This is true whether termination is caused by
11741 executing its return instruction
11742 or by throwing an exception to its caller
11743 (see <paramlink id="was_popped_by_exception"></paramlink>).
11744 However, frame pops caused by the <functionlink id="PopFrame"/>
11745 function are not reported.
11746 <p/>
11747 The location reported by <functionlink id="GetFrameLocation"></functionlink>
11748 identifies the executable location in the returning method,
11749 immediately prior to the return.
11750 </description>
11751 <origin>jvmdi</origin>
11752 <capabilities>
11753 <required id="can_generate_frame_pop_events"></required>
11754 </capabilities>
11755 <parameters>
11756 <param id="jni_env">
11757 <outptr>
11758 <struct>JNIEnv</struct>
11759 </outptr>
11760 <description>
11761 The JNI environment of the event (current) thread
11762 </description>
11763 </param>
11764 <param id="thread">
11765 <jthread/>
11766 <description>
11767 Thread that is popping the frame
11768 </description>
11769 </param>
11770 <param id="klass">
11771 <jclass method="method"/>
11772 <description>
11773 Class of the method being popped
11774 </description>
11775 </param>
11776 <param id="method">
11777 <jmethodID class="klass"/>
11778 <description>
11779 Method being popped
11780 </description>
11781 </param>
11782 <param id="was_popped_by_exception">
11783 <jboolean/>
11784 <description>
11785 True if frame was popped by a thrown exception.
11786 False if method exited through its return instruction.
11787 </description>
11788 </param>
11789 </parameters>
11790 </event>
11791
11792 <event label="Method Entry"
11793 id="MethodEntry" const="JVMTI_EVENT_METHOD_ENTRY" filtered="thread" num="65">
11794 <description>
11795 Method entry events are generated upon entry of Java
11796 programming language methods (including native methods).
11797 <p/>
11798 The location reported by <functionlink id="GetFrameLocation"></functionlink>
11799 identifies the initial executable location in
11800 the method.
11801 <p/>
11802 Enabling method
11803 entry or exit events will significantly degrade performance on many platforms and is thus
11804 not advised for performance critical usage (such as profiling).
11805 <internallink id="bci">Bytecode instrumentation</internallink> should be
11806 used in these cases.
11807 </description>
11808 <origin>jvmdi</origin>
11809 <capabilities>
11810 <required id="can_generate_method_entry_events"></required>
11811 </capabilities>
11812 <parameters>
11813 <param id="jni_env">
11814 <outptr>
11815 <struct>JNIEnv</struct>
11816 </outptr>
11817 <description>
11818 The JNI environment of the event (current) thread
11819 </description>
11820 </param>
11821 <param id="thread">
11822 <jthread/>
11823 <description>
11824 Thread entering the method
11825 </description>
11826 </param>
11827 <param id="klass">
11828 <jclass method="method"/>
11829 <description>
11830 Class of the method being entered
11831 </description>
11832 </param>
11833 <param id="method">
11834 <jmethodID class="klass"/>
11835 <description>
11836 Method being entered
11837 </description>
11838 </param>
11839 </parameters>
11840 </event>
11841
11842 <event label="Method Exit"
11843 id="MethodExit" const="JVMTI_EVENT_METHOD_EXIT" filtered="thread" num="66">
11844 <description>
11845 Method exit events are generated upon exit from Java
11846 programming language methods (including native methods).
11847 This is true whether termination is caused by
11848 executing its return instruction
11849 or by throwing an exception to its caller
11850 (see <paramlink id="was_popped_by_exception"></paramlink>).
11851 <p/>
11852 The <code>method</code> field uniquely identifies the
11853 method being entered or exited. The <code>frame</code> field provides
11854 access to the stack frame for the method.
11855 <p/>
11856 The location reported by <functionlink id="GetFrameLocation"></functionlink>
11857 identifies the executable location in the returning method
11858 immediately prior to the return.
11859 <p/>
11860 Enabling method
11861 entry or exit events will significantly degrade performance on many platforms and is thus
11862 not advised for performance critical usage (such as profiling).
11863 <internallink id="bci">Bytecode instrumentation</internallink> should be
11864 used in these cases.
11865 </description>
11866 <origin>jvmdi</origin>
11867 <capabilities>
11868 <required id="can_generate_method_exit_events"></required>
11869 </capabilities>
11870 <parameters>
11871 <param id="jni_env">
11872 <outptr>
11873 <struct>JNIEnv</struct>
11874 </outptr>
11875 <description>
11876 The JNI environment of the event (current) thread
11877 </description>
11878 </param>
11879 <param id="thread">
11880 <jthread/>
11881 <description>
11882 Thread exiting the method
11883 </description>
11884 </param>
11885 <param id="klass">
11886 <jclass method="method"/>
11887 <description>
11888 Class of the method being exited
11889 </description>
11890 </param>
11891 <param id="method">
11892 <jmethodID class="klass"/>
11893 <description>
11894 Method being exited
11895 </description>
11896 </param>
11897 <param id="was_popped_by_exception">
11898 <jboolean/>
11899 <description>
11900 True if frame was popped by a thrown exception.
11901 False if method exited through its return instruction.
11902 </description>
11903 </param>
11904 <param id="return_value">
11905 <jvalue/>
11906 <description>
11907 The return value of the method being exited.
11908 Undefined and should not be used if
11909 <paramlink id="was_popped_by_exception"></paramlink>
11910 is true.
11911 </description>
11912 </param>
11913 </parameters>
11914 </event>
11915
11916 <event label="Native Method Bind" phase="any"
11917 id="NativeMethodBind" const="JVMTI_EVENT_NATIVE_METHOD_BIND" num="67">
11918 <description>
11919 A Native Method Bind event is sent when a VM binds a
11920 Java programming language native method
11921 to the address of a function that implements the native method.
11922 This will occur when the native method is called for the first time
11923 and also occurs when the JNI function <code>RegisterNatives</code> is called.
11924 This event allows the bind to be redirected to an agent-specified
11925 proxy function.
11926 This event is not sent when the native method is unbound.
11927 Typically, this proxy function will need to be specific to a
11928 particular method or, to handle the general case, automatically
11929 generated assembly code, since after instrumentation code is
11930 executed the function at the original binding
11931 address will usually be invoked.
11932 The original binding can be restored or the redirection changed
11933 by use of the JNI function <code>RegisterNatives</code>.
11934 Some events may be sent during the primordial phase, JNI and
11935 most of <jvmti/> cannot be used at this time but the method and
11936 address can be saved for use later.
11937 </description>
11938 <origin>new</origin>
11939 <capabilities>
11940 <required id="can_generate_native_method_bind_events"></required>
11941 </capabilities>
11942 <parameters>
11943 <param id="jni_env">
11944 <outptr>
11945 <struct>JNIEnv</struct>
11946 </outptr>
11947 <description>
11948 The JNI environment of the event (current) thread
11949 Will be <code>NULL</code> if sent during the primordial
11950 <functionlink id="GetPhase">phase</functionlink>.
11951 </description>
11952 </param>
11953 <param id="thread">
11954 <jthread/>
11955 <description>
11956 Thread requesting the bind
11957 </description>
11958 </param>
11959 <param id="klass">
11960 <jclass method="method"/>
11961 <description>
11962 Class of the method being bound
11963 </description>
11964 </param>
11965 <param id="method">
11966 <jmethodID class="klass"/>
11967 <description>
11968 Native method being bound
11969 </description>
11970 </param>
11971 <param id="address">
11972 <outptr><void/></outptr>
11973 <description>
11974 The address the VM is about to bind to--that is, the
11975 address of the implementation of the native method
11976 </description>
11977 </param>
11978 <param id="new_address_ptr">
11979 <agentbuf><void/></agentbuf>
11980 <description>
11981 if the referenced address is changed (that is, if
11982 <code>*new_address_ptr</code> is set), the binding
11983 will instead be made to the supplied address.
11984 </description>
11985 </param>
11986 </parameters>
11987 </event>
11988
11989 <event label="Exception"
11990 id="Exception" const="JVMTI_EVENT_EXCEPTION" filtered="thread" num="58">
11991 <description>
11992 Exception events are generated whenever an exception is first detected
11993 in a Java programming language method.
11994 Where "exception" means any <code>java.lang.Throwable</code>.
11995 The exception may have been thrown by a Java programming language or native
11996 method, but in the case of native methods, the event is not generated
11997 until the exception is first seen by a Java programming language method. If an exception is
11998 set and cleared in a native method (and thus is never visible to Java programming language code),
11999 no exception event is generated.
12000 <p/>
12001 The <code>method</code> and <code>location</code>
12002 parameters uniquely identify the current location
12003 (where the exception was detected) and allow
12004 the mapping to source file and line number when that information is
12005 available. The <code>exception</code> field identifies the thrown
12006 exception object. The <code>catch_method</code>
12007 and <code>catch_location</code> identify the location of the catch clause,
12008 if any, that handles the thrown exception. If there is no such catch clause,
12009 each field is set to 0. There is no guarantee that the thread will ever
12010 reach this catch clause. If there are native methods on the call stack
12011 between the throw location and the catch clause, the exception may
12012 be reset by one of those native methods.
12013 Similarly, exceptions that are reported as uncaught (<code>catch_klass</code>
12014 et al. set to 0) may in fact be caught by native code.
12015 Agents can check for these occurrences by monitoring
12016 <eventlink id="ExceptionCatch"></eventlink> events.
12017 Note that finally clauses are implemented as catch and re-throw. Therefore they
12018 will be reported in the catch location.
12019 </description>
12020 <origin>jvmdi</origin>
12021 <capabilities>
12022 <required id="can_generate_exception_events"></required>
12023 </capabilities>
12024 <parameters>
12025 <param id="jni_env">
12026 <outptr>
12027 <struct>JNIEnv</struct>
12028 </outptr>
12029 <description>
12030 The JNI environment of the event (current) thread
12031 </description>
12032 </param>
12033 <param id="thread">
12034 <jthread/>
12035 <description>
12036 Thread generating the exception
12037 </description>
12038 </param>
12039 <param id="klass">
12040 <jclass method="method"/>
12041 <description>
12042 Class generating the exception
12043 </description>
12044 </param>
12045 <param id="method">
12046 <jmethodID class="klass"/>
12047 <description>
12048 Method generating the exception
12049 </description>
12050 </param>
12051 <param id="location">
12052 <jlocation/>
12053 <description>
12054 Location where exception occurred
12055 </description>
12056 </param>
12057 <param id="exception">
12058 <jobject/>
12059 <description>
12060 The exception being thrown
12061 </description>
12062 </param>
12063 <param id="catch_klass">
12064 <jclass method="catch_method"/>
12065 <description>
12066 Class that will catch the exception, or <code>NULL</code> if no known catch
12067 </description>
12068 </param>
12069 <param id="catch_method">
12070 <jmethodID class="catch_klass"/>
12071 <description>
12072 Method that will catch the exception, or <code>NULL</code> if no known catch
12073 </description>
12074 </param>
12075 <param id="catch_location">
12076 <jlocation/>
12077 <description>
12078 location which will catch the exception or zero if no known catch
12079 </description>
12080 </param>
12081 </parameters>
12082 </event>
12083
12084 <event label="Exception Catch"
12085 id="ExceptionCatch" const="JVMTI_EVENT_EXCEPTION_CATCH" filtered="thread" num="59">
12086 <description>
12087 Exception catch events are generated whenever a thrown exception is caught.
12088 Where "exception" means any <code>java.lang.Throwable</code>.
12089 If the exception is caught in a Java programming language method, the event is generated
12090 when the catch clause is reached. If the exception is caught in a native
12091 method, the event is generated as soon as control is returned to a Java programming language
12092 method. Exception catch events are generated for any exception for which
12093 a throw was detected in a Java programming language method.
12094 Note that finally clauses are implemented as catch and re-throw. Therefore they
12095 will generate exception catch events.
12096 <p/>
12097 The <code>method</code> and <code>location</code>
12098 parameters uniquely identify the current location
12099 and allow the mapping to source file and line number when that information is
12100 available. For exceptions caught in a Java programming language method, the
12101 <code>exception</code> object identifies the exception object. Exceptions
12102 caught in native methods are not necessarily available by the time the
12103 exception catch is reported, so the <code>exception</code> field is set
12104 to <code>NULL</code>.
12105 </description>
12106 <origin>jvmdi</origin>
12107 <capabilities>
12108 <required id="can_generate_exception_events"></required>
12109 </capabilities>
12110 <parameters>
12111 <param id="jni_env">
12112 <outptr>
12113 <struct>JNIEnv</struct>
12114 </outptr>
12115 <description>
12116 The JNI environment of the event (current) thread
12117 </description>
12118 </param>
12119 <param id="thread">
12120 <jthread/>
12121 <description>
12122 Thread catching the exception
12123 </description>
12124 </param>
12125 <param id="klass">
12126 <jclass method="method"/>
12127 <description>
12128 Class catching the exception
12129 </description>
12130 </param>
12131 <param id="method">
12132 <jmethodID class="klass"/>
12133 <description>
12134 Method catching the exception
12135 </description>
12136 </param>
12137 <param id="location">
12138 <jlocation/>
12139 <description>
12140 Location where exception is being caught
12141 </description>
12142 </param>
12143 <param id="exception">
12144 <jobject/>
12145 <description>
12146 Exception being caught
12147 </description>
12148 </param>
12149 </parameters>
12150 </event>
12151
12152 <event label="Thread Start"
12153 id="ThreadStart" const="JVMTI_EVENT_THREAD_START" num="52" phase="start">
12154 <description>
12155 Thread start events are generated by a new thread before its initial
12156 method executes.
12157 <p/>
12158 A thread may be listed in the array returned by
12159 <functionlink id="GetAllThreads"></functionlink>
12160 before its thread start event is generated.
12161 It is possible for other events to be generated
12162 on a thread before its thread start event.
12163 <p/>
12164 The event is sent on the newly started <paramlink id="thread"></paramlink>.
12165 </description>
12166 <origin>jvmdi</origin>
12167 <capabilities>
12168 </capabilities>
12169 <parameters>
12170 <param id="jni_env">
12171 <outptr>
12172 <struct>JNIEnv</struct>
12173 </outptr>
12174 <description>
12175 The JNI environment of the event (current) thread.
12176 </description>
12177 </param>
12178 <param id="thread">
12179 <jthread/>
12180 <description>
12181 Thread starting
12182 </description>
12183 </param>
12184 </parameters>
12185 </event>
12186
12187 <event label="Thread End"
12188 id="ThreadEnd" const="JVMTI_EVENT_THREAD_END" filtered="thread" num="53" phase="start">
12189 <description>
12190 Thread end events are generated by a terminating thread
12191 after its initial method has finished execution.
12192 <p/>
12193 A thread may be listed in the array returned by
12194 <functionlink id="GetAllThreads"></functionlink>
12195 after its thread end event is generated.
12196 No events are generated on a thread
12197 after its thread end event.
12198 <p/>
12199 The event is sent on the dying <paramlink id="thread"></paramlink>.
12200 </description>
12201 <origin>jvmdi</origin>
12202 <capabilities>
12203 </capabilities>
12204 <parameters>
12205 <param id="jni_env">
12206 <outptr>
12207 <struct>JNIEnv</struct>
12208 </outptr>
12209 <description>
12210 The JNI environment of the event (current) thread.
12211 </description>
12212 </param>
12213 <param id="thread">
12214 <jthread/>
12215 <description>
12216 Thread ending
12217 </description>
12218 </param>
12219 </parameters>
12220 </event>
12221
12222 <event label="Class Load"
12223 id="ClassLoad" const="JVMTI_EVENT_CLASS_LOAD" filtered="thread" phase="start" num="55">
12224 <description>
12225 A class load event is generated when a class is first loaded. The order
12226 of class load events generated by a particular thread are guaranteed
12227 to match the order of class loading within that thread.
12228 Array class creation does not generate a class load event.
12229 The creation of a primitive class (for example, java.lang.Integer.TYPE)
12230 does not generate a class load event.
12231 <p/>
12232 This event is sent at an early stage in loading the class. As
12233 a result the class should be used carefully. Note, for example,
12234 that methods and fields are not yet loaded, so queries for methods,
12235 fields, subclasses, and so on will not give correct results.
12236 See "Loading of Classes and Interfaces" in the <i>Java Language
12237 Specification</i>. For most
12238 purposes the <eventlink id="ClassPrepare"></eventlink> event will
12239 be more useful.
12240 </description>
12241 <origin>jvmdi</origin>
12242 <capabilities>
12243 </capabilities>
12244 <parameters>
12245 <param id="jni_env">
12246 <outptr>
12247 <struct>JNIEnv</struct>
12248 </outptr>
12249 <description>
12250 The JNI environment of the event (current) thread
12251 </description>
12252 </param>
12253 <param id="thread">
12254 <jthread/>
12255 <description>
12256 Thread loading the class
12257 </description>
12258 </param>
12259 <param id="klass">
12260 <jclass/>
12261 <description>
12262 Class being loaded
12263 </description>
12264 </param>
12265 </parameters>
12266 </event>
12267
12268 <elide>
12269 <event label="Class Unload"
12270 id="ClassUnload" const="JVMTI_EVENT_CLASS_UNLOAD" num="57">
12271 <description>
12272 A class unload event is generated when the class is about to be unloaded.
12273 Class unload events take place during garbage collection and must be
12274 handled extremely carefully. The garbage collector holds many locks
12275 and has suspended all other threads, so the event handler cannot depend
12276 on the ability to acquire any locks. The class unload event handler should
12277 do as little as possible, perhaps by queuing information to be processed
12278 later. In particular, the <code>jclass</code> should be used only in
12279 the JNI function <code>isSameObject</code> or in the following <jvmti/> functions:
12280 <ul>
12281 <li><functionlink id="GetClassSignature"></functionlink></li>
12282 <li><functionlink id="GetSourceFileName"></functionlink></li>
12283 <li><functionlink id="IsInterface"></functionlink></li>
12284 <li><functionlink id="IsArrayClass"></functionlink></li>
12285 </ul>
12286 </description>
12287 <origin>jvmdi</origin>
12288 <capabilities>
12289 </capabilities>
12290 <parameters>
12291 <param id="jni_env">
12292 <outptr>
12293 <struct>JNIEnv</struct>
12294 </outptr>
12295 <description>
12296 The JNI environment of the event (current) thread
12297 </description>
12298 </param>
12299 <param id="thread">
12300 <jthread/>
12301 <description>
12302 Thread generating the class unload
12303 </description>
12304 </param>
12305 <param id="klass">
12306 <jclass/>
12307 <description>
12308 Class being unloaded
12309 </description>
12310 </param>
12311 </parameters>
12312 </event>
12313 </elide>
12314
12315 <event label="Class Prepare"
12316 id="ClassPrepare" const="JVMTI_EVENT_CLASS_PREPARE" filtered="thread" phase="start" num="56">
12317 <description>
12318 A class prepare event is generated when class preparation is complete.
12319 At this point, class fields, methods, and implemented interfaces are
12320 available, and no code from the class has been executed. Since array
12321 classes never have fields or methods, class prepare events are not
12322 generated for them. Class prepare events are not generated for
12323 primitive classes (for example, <code>java.lang.Integer.TYPE</code>).
12324 </description>
12325 <origin>jvmdi</origin>
12326 <capabilities>
12327 </capabilities>
12328 <parameters>
12329 <param id="jni_env">
12330 <outptr>
12331 <struct>JNIEnv</struct>
12332 </outptr>
12333 <description>
12334 The JNI environment of the event (current) thread
12335 </description>
12336 </param>
12337 <param id="thread">
12338 <jthread/>
12339 <description>
12340 Thread generating the class prepare
12341 </description>
12342 </param>
12343 <param id="klass">
12344 <jclass/>
12345 <description>
12346 Class being prepared
12347 </description>
12348 </param>
12349 </parameters>
12350 </event>
12351
12352 <event label="Class File Load Hook" phase="any"
12353 id="ClassFileLoadHook" const="JVMTI_EVENT_CLASS_FILE_LOAD_HOOK" num="54">
12354 <description>
12355 This event is sent when the VM obtains class file data,
12356 but before it constructs
12357 the in-memory representation for that class.
12358 This event is also sent when the class is being modified by the
12359 <functionlink id="RetransformClasses"/> function or
12360 the <functionlink id="RedefineClasses"/> function,
12361 called in any <jvmti/> environment.
12362 The agent can instrument
12363 the existing class file data sent by the VM to include profiling/debugging hooks.
12364 See the description of
12365 <internallink id="bci">bytecode instrumentation</internallink>
12366 for usage information.
12367 <p/>
12368 This event may be sent before the VM is initialized (the primordial
12369 <functionlink id="GetPhase">phase</functionlink>). During this time
12370 no VM resources should be created. Some classes might not be compatible
12371 with the function (eg. ROMized classes) and this event will not be
12372 generated for these classes.
12373 <p/>
12374 The agent must allocate the space for the modified
12375 class file data buffer
12376 using the memory allocation function
12377 <functionlink id="Allocate"></functionlink> because the
12378 VM is responsible for freeing the new class file data buffer
12379 using <functionlink id="Deallocate"></functionlink>.
12380 Note that <functionlink id="Allocate"></functionlink>
12381 is permitted during the primordial phase.
12382 <p/>
12383 If the agent wishes to modify the class file, it must set
12384 <code>new_class_data</code> to point
12385 to the newly instrumented class file data buffer and set
12386 <code>new_class_data_len</code> to the length of that
12387 buffer before returning
12388 from this call. If no modification is desired, the agent simply
12389 does not set <code>new_class_data</code>. If multiple agents
12390 have enabled this event the results are chained. That is, if
12391 <code>new_class_data</code> has been set, it becomes the
12392 <code>class_data</code> for the next agent.
12393 <p/>
12394 The order that this event is sent to each environment differs
12395 from other events.
12396 This event is sent to environments in the following order:
12397 <ul>
12398 <li><fieldlink id="can_retransform_classes"
12399 struct="jvmtiCapabilities">retransformation
12400 incapable</fieldlink>
12401 environments, in the
12402 order in which they were created
12403 </li>
12404 <li><fieldlink id="can_retransform_classes"
12405 struct="jvmtiCapabilities">retransformation
12406 capable</fieldlink>
12407 environments, in the
12408 order in which they were created
12409 </li>
12410 </ul>
12411 When triggered by <functionlink id="RetransformClasses"/>,
12412 this event is sent only to <fieldlink id="can_retransform_classes"
12413 struct="jvmtiCapabilities">retransformation
12414 capable</fieldlink>
12415 environments.
12416 </description>
12417 <origin>jvmpi</origin>
12418 <capabilities>
12419 <capability id="can_generate_all_class_hook_events"></capability>
12420 </capabilities>
12421 <parameters>
12422 <param id="jni_env">
12423 <outptr>
12424 <struct>JNIEnv</struct>
12425 </outptr>
12426 <description>
12427 The JNI environment of the event (current) thread.
12428 Will be <code>NULL</code> if sent during the primordial
12429 <functionlink id="GetPhase">phase</functionlink>.
12430 </description>
12431 </param>
12432 <param id="class_being_redefined">
12433 <jclass/>
12434 <description>
12435 The class being
12436 <functionlink id="RedefineClasses">redefined</functionlink> or
12437 <functionlink id="RetransformClasses">retransformed</functionlink>.
12438 <code>NULL</code> if sent by class load.
12439 </description>
12440 </param>
12441 <param id="loader">
12442 <jobject/>
12443 <description>
12444 The class loader loading the class.
12445 <code>NULL</code> if the bootstrap class loader.
12446 </description>
12447 </param>
12448 <param id="name">
12449 <vmbuf><char/></vmbuf>
12450 <description>
12451 Name of class being loaded as a VM internal qualified name
12452 (for example, "java/util/List"), encoded as a
12453 <internallink id="mUTF">modified UTF-8</internallink> string.
12454 Note: if the class is defined with a <code>NULL</code> name or
12455 without a name specified, <code>name</code> will be <code>NULL</code>.
12456 </description>
12457 </param>
12458 <param id="protection_domain">
12459 <jobject/>
12460 <description>
12461 The <code>ProtectionDomain</code> of the class.
12462 </description>
12463 </param>
12464 <param id="class_data_len">
12465 <jint/>
12466 <description>
12467 Length of current class file data buffer.
12468 </description>
12469 </param>
12470 <param id="class_data">
12471 <vmbuf><uchar/></vmbuf>
12472 <description>
12473 Pointer to the current class file data buffer.
12474 </description>
12475 </param>
12476 <param id="new_class_data_len">
12477 <outptr><jint/></outptr>
12478 <description>
12479 Pointer to the length of the new class file data buffer.
12480 </description>
12481 </param>
12482 <param id="new_class_data">
12483 <agentbuf incount="new_class_data_len"><uchar/></agentbuf>
12484 <description>
12485 Pointer to the pointer to the instrumented class file data buffer.
12486 </description>
12487 </param>
12488 </parameters>
12489 </event>
12490
12491 <event label="VM Start Event"
12492 id="VMStart" const="JVMTI_EVENT_VM_START" num="57" phase="start">
12493 <description>
12494 The VM initialization event signals the start of the VM.
12495 At this time JNI is live but the VM is not yet fully initialized.
12496 Once this event is generated, the agent is free to call any JNI function.
12497 This event signals the beginning of the start phase,
12498 <jvmti/> functions permitted in the start phase may be called.
12499 <p/>
12500 In the case of VM start-up failure, this event will not be sent.
12501 </description>
12502 <origin>jvmdi</origin>
12503 <capabilities>
12504 </capabilities>
12505 <parameters>
12506 <param id="jni_env">
12507 <outptr>
12508 <struct>JNIEnv</struct>
12509 </outptr>
12510 <description>
12511 The JNI environment of the event (current) thread.
12512 </description>
12513 </param>
12514 </parameters>
12515 </event>
12516
12517 <event label="VM Initialization Event"
12518 id="VMInit" const="JVMTI_EVENT_VM_INIT" num="50">
12519 <description>
12520 The VM initialization event signals the completion of VM initialization. Once
12521 this event is generated, the agent is free to call any JNI or <jvmti/>
12522 function. The VM initialization event can be preceded by or can be concurrent
12523 with other events, but
12524 the preceding events should be handled carefully, if at all, because the
12525 VM has not completed its initialization. The thread start event for the
12526 main application thread is guaranteed not to occur until after the
12527 handler for the VM initialization event returns.
12528 <p/>
12529 In the case of VM start-up failure, this event will not be sent.
12530 </description>
12531 <origin>jvmdi</origin>
12532 <capabilities>
12533 </capabilities>
12534 <parameters>
12535 <param id="jni_env">
12536 <outptr>
12537 <struct>JNIEnv</struct>
12538 </outptr>
12539 <description>
12540 The JNI environment of the event (current) thread.
12541 </description>
12542 </param>
12543 <param id="thread">
12544 <jthread/>
12545 <description>
12546 The initial thread
12547 </description>
12548 </param>
12549 </parameters>
12550 </event>
12551
12552 <event label="VM Death Event"
12553 id="VMDeath" const="JVMTI_EVENT_VM_DEATH" num="51">
12554 <description>
12555 The VM death event notifies the agent of the termination of the VM.
12556 No events will occur after the VMDeath event.
12557 <p/>
12558 In the case of VM start-up failure, this event will not be sent.
12559 Note that <internallink id="onunload">Agent_OnUnload</internallink>
12560 will still be called in these cases.
12561 </description>
12562 <origin>jvmdi</origin>
12563 <capabilities>
12564 </capabilities>
12565 <parameters>
12566 <param id="jni_env">
12567 <outptr>
12568 <struct>JNIEnv</struct>
12569 </outptr>
12570 <description>
12571 The JNI environment of the event (current) thread
12572 </description>
12573 </param>
12574 </parameters>
12575 </event>
12576
12577 <event label="Compiled Method Load"
12578 id="CompiledMethodLoad" const="JVMTI_EVENT_COMPILED_METHOD_LOAD" num="68">
12579 <description>
12580 Sent when a method is compiled and loaded into memory by the VM.
12581 If it is unloaded, the <eventlink id="CompiledMethodUnload"/> event is sent.
12582 If it is moved, the <eventlink id="CompiledMethodUnload"/> event is sent,
12583 followed by a new <code>CompiledMethodLoad</code> event.
12584 Note that a single method may have multiple compiled forms, and that
12585 this event will be sent for each form.
12586 Note also that several methods may be inlined into a single
12587 address range, and that this event will be sent for each method.
12588 <p/>
12589 These events can be sent after their initial occurrence with
12590 <functionlink id="GenerateEvents"></functionlink>.
12591 </description>
12592 <origin>jvmpi</origin>
12593 <typedef id="jvmtiAddrLocationMap" label="Native address to location entry">
12594 <field id="start_address">
12595 <vmbuf><void/></vmbuf>
12596 <description>
12597 Starting native address of code corresponding to a location
12598 </description>
12599 </field>
12600 <field id="location">
12601 <jlocation/>
12602 <description>
12603 Corresponding location. See
12604 <functionlink id="GetJLocationFormat"></functionlink>
12605 for the meaning of location.
12606 </description>
12607 </field>
12608 </typedef>
12609 <capabilities>
12610 <required id="can_generate_compiled_method_load_events"></required>
12611 </capabilities>
12612 <parameters>
12613 <param id="klass">
12614 <jclass method="method"/>
12615 <description>
12616 Class of the method being compiled and loaded
12617 </description>
12618 </param>
12619 <param id="method">
12620 <jmethodID class="klass"/>
12621 <description>
12622 Method being compiled and loaded
12623 </description>
12624 </param>
12625 <param id="code_size">
12626 <jint/>
12627 <description>
12628 Size of compiled code
12629 </description>
12630 </param>
12631 <param id="code_addr">
12632 <vmbuf><void/></vmbuf>
12633 <description>
12634 Address where compiled method code is loaded
12635 </description>
12636 </param>
12637 <param id="map_length">
12638 <jint/>
12639 <description>
12640 Number of <typelink id="jvmtiAddrLocationMap"></typelink>
12641 entries in the address map.
12642 Zero if mapping information cannot be supplied.
12643 </description>
12644 </param>
12645 <param id="map">
12646 <vmbuf><struct>jvmtiAddrLocationMap</struct></vmbuf>
12647 <description>
12648 Map from native addresses to location.
12649 The native address range of each entry is from
12650 <fieldlink id="start_address" struct="jvmtiAddrLocationMap"></fieldlink>
12651 to <code>start_address-1</code> of the next entry.
12652 <code>NULL</code> if mapping information cannot be supplied.
12653 </description>
12654 </param>
12655 <param id="compile_info">
12656 <vmbuf><void/></vmbuf>
12657 <description>
12658 VM-specific compilation information.
12659 The referenced compile information is managed by the VM
12660 and must not depend on the agent for collection.
12661 A VM implementation defines the content and lifetime
12662 of the information.
12663 </description>
12664 </param>
12665 </parameters>
12666 </event>
12667
12668 <event label="Compiled Method Unload"
12669 id="CompiledMethodUnload" const="JVMTI_EVENT_COMPILED_METHOD_UNLOAD" num="69">
12670 <description>
12671 Sent when a compiled method is unloaded from memory.
12672 This event might not be sent on the thread which performed the unload.
12673 This event may be sent sometime after the unload occurs, but
12674 will be sent before the memory is reused
12675 by a newly generated compiled method. This event may be sent after
12676 the class is unloaded.
12677 </description>
12678 <origin>jvmpi</origin>
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 compiled method being unloaded.
12687 </description>
12688 </param>
12689 <param id="method">
12690 <jmethodID class="klass"/>
12691 <description>
12692 Compiled method being unloaded.
12693 For identification of the compiled method only -- the class
12694 may be unloaded and therefore the method should not be used
12695 as an argument to further JNI or <jvmti/> functions.
12696 </description>
12697 </param>
12698 <param id="code_addr">
12699 <vmbuf><void/></vmbuf>
12700 <description>
12701 Address where compiled method code was loaded.
12702 For identification of the compiled method only --
12703 the space may have been reclaimed.
12704 </description>
12705 </param>
12706 </parameters>
12707 </event>
12708
12709 <event label="Dynamic Code Generated" phase="any"
12710 id="DynamicCodeGenerated" const="JVMTI_EVENT_DYNAMIC_CODE_GENERATED" num="70">
12711 <description>
12712 Sent when a component of the virtual machine is generated dynamically.
12713 This does not correspond to Java programming language code that is
12714 compiled--see <eventlink id="CompiledMethodLoad"></eventlink>.
12715 This is for native code--for example, an interpreter that is generated
12716 differently depending on command-line options.
12717 <p/>
12718 Note that this event has no controlling capability.
12719 If a VM cannot generate these events, it simply does not send any.
12720 <p/>
12721 These events can be sent after their initial occurrence with
12722 <functionlink id="GenerateEvents"></functionlink>.
12723 </description>
12724 <origin>jvmpi</origin>
12725 <capabilities>
12726 </capabilities>
12727 <parameters>
12728 <param id="name">
12729 <vmbuf><char/></vmbuf>
12730 <description>
12731 Name of the code, encoded as a
12732 <internallink id="mUTF">modified UTF-8</internallink> string.
12733 Intended for display to an end-user.
12734 The name might not be unique.
12735 </description>
12736 </param>
12737 <param id="address">
12738 <vmbuf><void/></vmbuf>
12739 <description>
12740 Native address of the code
12741 </description>
12742 </param>
12743 <param id="length">
12744 <jint/>
12745 <description>
12746 Length in bytes of the code
12747 </description>
12748 </param>
12749 </parameters>
12750 </event>
12751
12752 <event label="Data Dump Request"
12753 id="DataDumpRequest" const="JVMTI_EVENT_DATA_DUMP_REQUEST" num="71">
12754 <description>
12755 Sent by the VM to request the agent to dump its data. This
12756 is just a hint and the agent need not react to this event.
12757 This is useful for processing command-line signals from users. For
12758 example, in the Java 2 SDK a CTRL-Break on Win32 and a CTRL-\ on Solaris
12759 causes the VM to send this event to the agent.
12760 </description>
12761 <origin>jvmpi</origin>
12762 <capabilities>
12763 </capabilities>
12764 <parameters>
12765 </parameters>
12766 </event>
12767
12768 <event label="Monitor Contended Enter"
12769 id="MonitorContendedEnter" const="JVMTI_EVENT_MONITOR_CONTENDED_ENTER" filtered="thread" num="75">
12770 <description>
12771 Sent when a thread is attempting to enter a Java programming language
12772 monitor already acquired by another thread.
12773 </description>
12774 <origin>jvmpi</origin>
12775 <capabilities>
12776 <required id="can_generate_monitor_events"></required>
12777 </capabilities>
12778 <parameters>
12779 <param id="jni_env">
12780 <outptr>
12781 <struct>JNIEnv</struct>
12782 </outptr>
12783 <description>
12784 The JNI environment of the event (current) thread
12785 </description>
12786 </param>
12787 <param id="thread">
12788 <jthread/>
12789 <description>
12790 JNI local reference to the thread
12791 attempting to enter the monitor
12792 </description>
12793 </param>
12794 <param id="object">
12795 <jobject/>
12796 <description>
12797 JNI local reference to the monitor
12798 </description>
12799 </param>
12800 </parameters>
12801 </event>
12802
12803 <event label="Monitor Contended Entered"
12804 id="MonitorContendedEntered" const="JVMTI_EVENT_MONITOR_CONTENDED_ENTERED" filtered="thread" num="76">
12805 <description>
12806 Sent when a thread enters a Java programming language
12807 monitor after waiting for it to be released by another thread.
12808 </description>
12809 <origin>jvmpi</origin>
12810 <capabilities>
12811 <required id="can_generate_monitor_events"></required>
12812 </capabilities>
12813 <parameters>
12814 <param id="jni_env">
12815 <outptr>
12816 <struct>JNIEnv</struct>
12817 </outptr>
12818 <description>
12819 The JNI environment of the event (current) thread
12820 </description>
12821 </param>
12822 <param id="thread">
12823 <jthread/>
12824 <description>
12825 JNI local reference to the thread entering
12826 the monitor
12827 </description>
12828 </param>
12829 <param id="object">
12830 <jobject/>
12831 <description>
12832 JNI local reference to the monitor
12833 </description>
12834 </param>
12835 </parameters>
12836 </event>
12837
12838 <event label="Monitor Wait"
12839 id="MonitorWait" const="JVMTI_EVENT_MONITOR_WAIT" filtered="thread" num="73">
12840 <description>
12841 Sent when a thread is about to wait on an object.
12842 </description>
12843 <origin>jvmpi</origin>
12844 <capabilities>
12845 <required id="can_generate_monitor_events"></required>
12846 </capabilities>
12847 <parameters>
12848 <param id="jni_env">
12849 <outptr>
12850 <struct>JNIEnv</struct>
12851 </outptr>
12852 <description>
12853 The JNI environment of the event (current) thread
12854 </description>
12855 </param>
12856 <param id="thread">
12857 <jthread/>
12858 <description>
12859 JNI local reference to the thread about to wait
12860 </description>
12861 </param>
12862 <param id="object">
12863 <jobject/>
12864 <description>
12865 JNI local reference to the monitor
12866 </description>
12867 </param>
12868 <param id="timeout">
12869 <jlong/>
12870 <description>
12871 The number of milliseconds the thread will wait
12872 </description>
12873 </param>
12874 </parameters>
12875 </event>
12876
12877 <event label="Monitor Waited"
12878 id="MonitorWaited" const="JVMTI_EVENT_MONITOR_WAITED" filtered="thread" num="74">
12879 <description>
12880 Sent when a thread finishes waiting on an object.
12881 </description>
12882 <origin>jvmpi</origin>
12883 <capabilities>
12884 <required id="can_generate_monitor_events"></required>
12885 </capabilities>
12886 <parameters>
12887 <param id="jni_env">
12888 <outptr>
12889 <struct>JNIEnv</struct>
12890 </outptr>
12891 <description>
12892 The JNI environment of the event (current) thread
12893 </description>
12894 </param>
12895 <param id="thread">
12896 <jthread/>
12897 <description>
12898 JNI local reference to the thread that was finished waiting
12899 </description>
12900 </param>
12901 <param id="object">
12902 <jobject/>
12903 <description>
12904 JNI local reference to the monitor.
12905 </description>
12906 </param>
12907 <param id="timed_out">
12908 <jboolean/>
12909 <description>
12910 True if the monitor timed out
12911 </description>
12912 </param>
12913 </parameters>
12914 </event>
12915
12916 <event label="Resource Exhausted"
12917 id="ResourceExhausted" const="JVMTI_EVENT_RESOURCE_EXHAUSTED" num="80"
12918 since="1.1">
12919 <description>
12920 Sent when a VM resource needed by a running application has been exhausted.
12921 Except as required by the optional capabilities, the set of resources
12922 which report exhaustion is implementation dependent.
12923 <p/>
12924 The following bit flags define the properties of the resource exhaustion:
12925 <constants id="jvmtiResourceExhaustionFlags"
12926 label="Resource Exhaustion Flags"
12927 kind="bits"
12928 since="1.1">
12929 <constant id="JVMTI_RESOURCE_EXHAUSTED_OOM_ERROR" num="0x0001">
12930 After this event returns, the VM will throw a
12931 <code>java.lang.OutOfMemoryError</code>.
12932 </constant>
12933 <constant id="JVMTI_RESOURCE_EXHAUSTED_JAVA_HEAP" num="0x0002">
12934 The VM was unable to allocate memory from the <tm>Java</tm>
12935 platform <i>heap</i>.
12936 The <i>heap</i> is the runtime
12937 data area from which memory for all class instances and
12938 arrays are allocated.
12939 </constant>
12940 <constant id="JVMTI_RESOURCE_EXHAUSTED_THREADS" num="0x0004">
12941 The VM was unable to create a thread.
12942 </constant>
12943 </constants>
12944 </description>
12945 <origin>new</origin>
12946 <capabilities>
12947 <capability id="can_generate_resource_exhaustion_heap_events">
12948 Can generate events when the VM is unable to allocate memory from the
12949 <internallink id="JVMTI_RESOURCE_EXHAUSTED_JAVA_HEAP">heap</internallink>.
12950 </capability>
12951 <capability id="can_generate_resource_exhaustion_threads_events">
12952 Can generate events when the VM is unable to
12953 <internallink id="JVMTI_RESOURCE_EXHAUSTED_THREADS">create
12954 a thread</internallink>.
12955 </capability>
12956 </capabilities>
12957 <parameters>
12958 <param id="jni_env">
12959 <outptr>
12960 <struct>JNIEnv</struct>
12961 </outptr>
12962 <description>
12963 The JNI environment of the event (current) thread
12964 </description>
12965 </param>
12966 <param id="flags">
12967 <jint/>
12968 <description>
12969 Flags defining the properties of the of resource exhaustion
12970 as specified by the
12971 <internallink id="jvmtiResourceExhaustionFlags">Resource
12972 Exhaustion Flags</internallink>.
12973 </description>
12974 </param>
12975 <param id="reserved">
12976 <vmbuf><void/></vmbuf>
12977 <description>
12978 Reserved.
12979 </description>
12980 </param>
12981 <param id="description">
12982 <vmbuf><char/></vmbuf>
12983 <description>
12984 Description of the resource exhaustion, encoded as a
12985 <internallink id="mUTF">modified UTF-8</internallink> string.
12986 </description>
12987 </param>
12988 </parameters>
12989 </event>
12990
12991 <event label="VM Object Allocation"
12992 id="VMObjectAlloc" const="JVMTI_EVENT_VM_OBJECT_ALLOC" num="84">
12993 <description>
12994 Sent when a method causes the virtual machine to allocate an
12995 Object visible to Java programming language code and the
12996 allocation is not detectable by other intrumentation mechanisms.
12997 Generally object allocation should be detected by instrumenting
12998 the bytecodes of allocating methods.
12999 Object allocation generated in native code by JNI function
13000 calls should be detected using
13001 <internallink id="jniIntercept">JNI function interception</internallink>.
13002 Some methods might not have associated bytecodes and are not
13003 native methods, they instead are executed directly by the
13004 VM. These methods should send this event.
13005 Virtual machines which are incapable of bytecode instrumentation
13006 for some or all of their methods can send this event.
13007 <p/>
13008 Typical examples where this event might be sent:
13009 <ul>
13010 <li>Reflection -- for example, <code>java.lang.Class.newInstance()</code></li>
13011 <li>Methods not represented by bytecodes -- for example, VM intrinsics and
13012 J2ME preloaded classes</li>
13013 </ul>
13014 Cases where this event would not be generated:
13015 <ul>
13016 <li>Allocation due to bytecodes -- for example, the <code>new</code>
13017 and <code>newarray</code> VM instructions</li>
13018 <li>Allocation due to JNI function calls -- for example,
13019 <code>AllocObject</code></li>
13020 <li>Allocations during VM initialization</li>
13021 <li>VM internal objects</li>
13022 </ul>
13023 </description>
13024 <origin>new</origin>
13025 <capabilities>
13026 <required id="can_generate_vm_object_alloc_events"></required>
13027 </capabilities>
13028 <parameters>
13029 <param id="jni_env">
13030 <outptr>
13031 <struct>JNIEnv</struct>
13032 </outptr>
13033 <description>
13034 The JNI environment of the event (current) thread
13035 </description>
13036 </param>
13037 <param id="thread">
13038 <jthread/>
13039 <description>
13040 Thread allocating the object.
13041 </description>
13042 </param>
13043 <param id="object">
13044 <jobject/>
13045 <description>
13046 JNI local reference to the object that was allocated
13047 </description>
13048 </param>
13049 <param id="object_klass">
13050 <jclass/>
13051 <description>
13052 JNI local reference to the class of the object
13053 </description>
13054 </param>
13055 <param id="size">
13056 <jlong/>
13057 <description>
13058 Size of the object (in bytes). See <functionlink id="GetObjectSize"/>.
13059 </description>
13060 </param>
13061 </parameters>
13062 </event>
13063
13064 <event label="Object Free"
13065 id="ObjectFree" const="JVMTI_EVENT_OBJECT_FREE" num="83">
13066 <description>
13067 An Object Free event is sent when the garbage collector frees an object.
13068 Events are only sent for tagged objects--see
13069 <internallink id="Heap">heap functions</internallink>.
13070 <p/>
13071 The event handler must not use JNI functions and
13072 must not use <jvmti/> functions except those which
13073 specifically allow such use (see the raw monitor, memory management,
13074 and environment local storage functions).
13075 </description>
13076 <origin>new</origin>
13077 <capabilities>
13078 <required id="can_generate_object_free_events"></required>
13079 </capabilities>
13080 <parameters>
13081 <param id="tag">
13082 <jlong/>
13083 <description>
13084 The freed object's tag
13085 </description>
13086 </param>
13087 </parameters>
13088 </event>
13089
13090 <event label="Garbage Collection Start"
13091 id="GarbageCollectionStart" const="JVMTI_EVENT_GARBAGE_COLLECTION_START" num="81">
13092 <description>
13093 A Garbage Collection Start event is sent when a
13094 garbage collection pause begins.
13095 Only stop-the-world collections are reported--that is, collections during
13096 which all threads cease to modify the state of the Java virtual machine.
13097 This means that some collectors will never generate these events.
13098 This event is sent while the VM is still stopped, thus
13099 the event handler must not use JNI functions and
13100 must not use <jvmti/> functions except those which
13101 specifically allow such use (see the raw monitor, memory management,
13102 and environment local storage functions).
13103 <p/>
13104 This event is always sent as a matched pair with
13105 <eventlink id="GarbageCollectionFinish"/>
13106 (assuming both events are enabled) and no garbage collection
13107 events will occur between them.
13108 </description>
13109 <origin>new</origin>
13110 <capabilities>
13111 <required id="can_generate_garbage_collection_events"></required>
13112 </capabilities>
13113 <parameters>
13114 </parameters>
13115 </event>
13116
13117 <event label="Garbage Collection Finish"
13118 id="GarbageCollectionFinish" const="JVMTI_EVENT_GARBAGE_COLLECTION_FINISH" num="82">
13119 <description>
13120 A Garbage Collection Finish event is sent when a
13121 garbage collection pause ends.
13122 This event is sent while the VM is still stopped, thus
13123 the event handler must not use JNI functions and
13124 must not use <jvmti/> functions except those which
13125 specifically allow such use (see the raw monitor, memory management,
13126 and environment local storage functions).
13127 <p/>
13128 Some agents may need to do post garbage collection operations that
13129 require the use of the disallowed <jvmti/> or JNI functions. For these
13130 cases an agent thread can be created which waits on a raw monitor,
13131 and the handler for the Garbage Collection Finish event simply
13132 notifies the raw monitor
13133 <p/>
13134 This event is always sent as a matched pair with
13135 <eventlink id="GarbageCollectionStart"/> (assuming both events are enabled).
13136 <issue>
13137 The most important use of this event is to provide timing information,
13138 and thus additional information is not required. However,
13139 information about the collection which is "free" should be included -
13140 what that information is needs to be determined.
13141 </issue>
13142 </description>
13143 <origin>new</origin>
13144 <capabilities>
13145 <required id="can_generate_garbage_collection_events"></required>
13146 </capabilities>
13147 <parameters>
13148 </parameters>
13149 </event>
13150
13151 <elide>
13152 <event label="Verbose Output" phase="any"
13153 id="VerboseOutput" const="JVMTI_EVENT_VERBOSE_OUTPUT" num="85">
13154 <description>
13155 Send verbose messages as strings.
13156 <issue>
13157 This format is extremely fragile, as it can change with each
13158 platform, collector and version. Alternatives include:
13159 <ul>
13160 <li>building off Java programming language M and M APIs</li>
13161 <li>XML</li>
13162 <li>key/value pairs</li>
13163 <li>removing it</li>
13164 </ul>
13165 </issue>
13166 <issue>
13167 Though this seemed trivial to implement.
13168 In the RI it appears this will be quite complex.
13169 </issue>
13170 </description>
13171 <origin>new</origin>
13172 <capabilities>
13173 </capabilities>
13174 <parameters>
13175 <param id="flag">
13176 <enum>jvmtiVerboseFlag</enum>
13177 <description>
13178 Which verbose output is being sent.
13179 </description>
13180 </param>
13181 <param id="message">
13182 <vmbuf><char/></vmbuf>
13183 <description>
13184 Message text, encoded as a
13185 <internallink id="mUTF">modified UTF-8</internallink> string.
13186 </description>
13187 </param>
13188 </parameters>
13189 </event>
13190 </elide>
13191
13192 </eventsection>
13193
13194 <datasection>
13195 <intro>
13196 <jvmti/> extends the data types defined by JNI.
13197 </intro>
13198 <basetypes id="jniTypes" label="JNI Types Used in the JVM Tool Interface">
13199 <basetype id="jboolean">
13200 <description>
13201 Holds a Java programming language <code>boolean</code>.
13202 Unsigned 8 bits.
13203 </description>
13204 </basetype>
13205 <basetype id="jchar">
13206 <description>
13207 Holds a Java programming language <code>char</code>.
13208 Unsigned 16 bits.
13209 </description>
13210 </basetype>
13211 <basetype id="jint">
13212 <description>
13213 Holds a Java programming language <code>int</code>.
13214 Signed 32 bits.
13215 </description>
13216 </basetype>
13217 <basetype id="jlong">
13218 <description>
13219 Holds a Java programming language <code>long</code>.
13220 Signed 64 bits.
13221 </description>
13222 </basetype>
13223 <basetype id="jfloat">
13224 <description>
13225 Holds a Java programming language <code>float</code>.
13226 32 bits.
13227 </description>
13228 </basetype>
13229 <basetype id="jdouble">
13230 <description>
13231 Holds a Java programming language <code>double</code>.
13232 64 bits.
13233 </description>
13234 </basetype>
13235 <basetype id="jobject">
13236 <description>
13237 Holds a Java programming language object.
13238 </description>
13239 </basetype>
13240 <basetype id="jclass">
13241 <description>
13242 Holds a Java programming language class.
13243 </description>
13244 </basetype>
13245 <basetype id="jvalue">
13246 <description>
13247 Is a union of all primitive types and <code>jobject</code>. Thus, holds any Java
13248 programming language value.
13249 </description>
13250 </basetype>
13251 <basetype id="jfieldID">
13252 <description>
13253 Identifies a Java programming language field.
13254 <code>jfieldID</code>s returned by <jvmti/> functions and events may be
13255 safely stored.
13256 </description>
13257 </basetype>
13258 <basetype id="jmethodID">
13259 <description>
13260 Identifies a Java programming language method, initializer, or constructor.
13261 <code>jmethodID</code>s returned by <jvmti/> functions and events may be
13262 safely stored. However, if the class is unloaded, they become invalid
13263 and must not be used.
13264 </description>
13265 </basetype>
13266 <basetype id="JNIEnv">
13267 <description>
13268 Pointer to the JNI function table. Pointer to this (<code>JNIEnv *</code>)
13269 is a JNI environment.
13270 </description>
13271 </basetype>
13272 </basetypes>
13273
13274 <basetypes id="jvmtiTypes" label="JVM Tool Interface Base Types">
13275 <basetype id="jvmtiEnv">
13276 <description>
13277 The <jvmti/> <internallink id="environments">environment</internallink> pointer.
13278 See the <internallink id="FunctionSection">Function Section</internallink>.
13279 <code>jvmtiEnv</code> points to the
13280 <internallink id="FunctionTable">function table</internallink> pointer.
13281 </description>
13282 </basetype>
13283 <basetype id="jthread">
13284 <definition>typedef jobject jthread;</definition>
13285 <description>
13286 Subtype of <datalink id="jobject"></datalink> that holds a thread.
13287 </description>
13288 </basetype>
13289 <basetype id="jthreadGroup">
13290 <definition>typedef jobject jthreadGroup;</definition>
13291 <description>
13292 Subtype of <datalink id="jobject"></datalink> that holds a thread group.
13293 </description>
13294 </basetype>
13295 <basetype id="jlocation">
13296 <definition>typedef jlong jlocation;</definition>
13297 <description>
13298 A 64 bit value, representing a monotonically increasing
13299 executable position within a method.
13300 <code>-1</code> indicates a native method.
13301 See <functionlink id="GetJLocationFormat"></functionlink> for the format on a
13302 given VM.
13303 </description>
13304 </basetype>
13305 <basetype id="jrawMonitorID">
13306 <definition>struct _jrawMonitorID;
13307 typedef struct _jrawMonitorID *jrawMonitorID;</definition>
13308 <description>
13309 A raw monitor.
13310 </description>
13311 </basetype>
13312 <basetype id="jvmtiError">
13313 <description>
13314 Holds an error return code.
13315 See the <internallink id="ErrorSection">Error section</internallink> for possible values.
13316 <example>
13317 typedef enum {
13318 JVMTI_ERROR_NONE = 0,
13319 JVMTI_ERROR_INVALID_THREAD = 10,
13320 ...
13321 } jvmtiError;
13322 </example>
13323 </description>
13324 </basetype>
13325 <basetype id="jvmtiEvent">
13326 <description>
13327 An identifier for an event type.
13328 See the <internallink id="EventSection">Event section</internallink> for possible values.
13329 It is guaranteed that future versions of this specification will
13330 never assign zero as an event type identifier.
13331 <example>
13332 typedef enum {
13333 JVMTI_EVENT_SINGLE_STEP = 1,
13334 JVMTI_EVENT_BREAKPOINT = 2,
13335 ...
13336 } jvmtiEvent;
13337 </example>
13338 </description>
13339 </basetype>
13340 <basetype id="jvmtiEventCallbacks">
13341 <description>
13342 The callbacks used for events.
13343 <example>
13344 typedef struct {
13345 jvmtiEventVMInit VMInit;
13346 jvmtiEventVMDeath VMDeath;
13347 ...
13348 } jvmtiEventCallbacks;
13349 </example>
13350 See <internallink id="jvmtiEventCallbacks">event callbacks</internallink>
13351 for the complete structure.
13352 <p/>
13353 Where, for example, the VM initialization callback is defined:
13354 <example>
13355 typedef void (JNICALL *jvmtiEventVMInit)
13356 (jvmtiEnv *jvmti_env,
13357 JNIEnv* jni_env,
13358 jthread thread);
13359 </example>
13360 See the individual events for the callback function definition.
13361 </description>
13362 </basetype>
13363 <basetype id="jniNativeInterface">
13364 <definition>typedef struct JNINativeInterface_ jniNativeInterface;</definition>
13365 <description>
13366 Typedef for the JNI function table <code>JNINativeInterface</code>
13367 defined in the
13368 <externallink id="http://docs.oracle.com/javase/7/docs/technotes/guides/jni/spec/functions.html#wp23720">JNI Specification</externallink>.
13369 The JNI reference implementation defines this with an underscore.
13370 </description>
13371 </basetype>
13372 </basetypes>
13373
13374 </datasection>
13375
13376 <issuessection label="Issues">
13377 <intro id="suspendRequired" label="Resolved Issue: Suspend - Required or Automatic">
13378 JVMDI requires that the agent suspend threads before calling
13379 certain sensitive functions. JVMPI requires garbage collection to be
13380 disabled before calling certain sensitive functions.
13381 It was suggested that rather than have this requirement, that
13382 VM place itself in a suitable state before performing an
13383 operation. This makes considerable sense since each VM
13384 knows its requirements and can most easily arrange a
13385 safe state.
13386 <p/>
13387 The ability to externally suspend/resume threads will, of
13388 course, remain. The ability to enable/disable garbage collection will not.
13389 <p/>
13390 This issue is resolved--suspend will not
13391 be required. The spec has been updated to reflect this.
13392 </intro>
13393
13394 <intro id="stackSampling" label="Resolved Issue: Call Stack Sampling">
13395 There are a variety of approaches to sampling call stacks.
13396 The biggest bifurcation is between VM controlled and agent
13397 controlled.
13398 <p/>
13399 This issue is resolved--agent controlled
13400 sampling will be the approach.
13401 </intro>
13402
13403 <intro id="threadRepresentation" label="Resolved Issue: Thread Representation">
13404 JVMDI represents threads as jthread. JVMPI primarily
13405 uses JNIEnv* to represent threads.
13406 <p/>
13407 The Expert Group has chosen jthread as the representation
13408 for threads in <jvmti/>.
13409 JNIEnv* is sent by
13410 events since it is needed to JNI functions. JNIEnv, per the
13411 JNI spec, are not supposed to be used outside their thread.
13412 </intro>
13413
13414 <intro id="design" label="Resolved Issue: Method Representation">
13415 The JNI spec allows an implementation to depend on jclass/jmethodID
13416 pairs, rather than simply a jmethodID, to reference a method.
13417 JVMDI, for consistency, choose the same representation.
13418 JVMPI, however, specifies that a jmethodID alone maps to a
13419 method. Both of the Sun <tm>J2SE</tm> virtual machines (Classic and <tm>HotSpot</tm>) store
13420 pointers in jmethodIDs, and as a result, a jmethodID is sufficient.
13421 In fact, any JVM implementation that supports JVMPI must have
13422 such a representation.
13423 <jvmti/> will use jmethodID as a unique representation of a method
13424 (no jclass is used).
13425 There should be efficiency gains, particularly in
13426 functionality like stack dumping, to this representation.
13427 <p/>
13428 Note that fields were not used in JVMPI and that the access profile
13429 of fields differs from methods--for implementation efficiency
13430 reasons, a jclass/jfieldID pair will still be needed for field
13431 reference.
13432 </intro>
13433
13434 <intro id="localReferenceIssue" label="Resolved Issue: Local References">
13435 Functions return local references.
13436 </intro>
13437
13438 <intro id="frameRep" label="Resolved Issue: Representation of frames">
13439 In JVMDI, a frame ID is used to represent a frame. Problem with this
13440 is that a VM must track when a frame becomes invalid, a far better
13441 approach, and the one used in <jvmti/>, is to reference frames by depth.
13442 </intro>
13443
13444 <intro id="requiredCapabilities" label="Issue: Required Capabilities">
13445 Currently, having a required capabilities means that the functionality
13446 is optional. Capabilities are useful even for required functionality
13447 since they can inform the VM is needed set-up. Thus, there should be
13448 a set of capabilities that a conformant implementation must provide
13449 (if requested during Agent_OnLoad).
13450 </intro>
13451
13452 <intro id="taghint" label="Proposal: add tag hint function">
13453 A hint of the percentage of objects that will be tagged would
13454 help the VM pick a good implementation.
13455 </intro>
13456
13457 <intro id="moreMonitorQueries" label="Request: More Monitor Quires">
13458 How difficult or easy would be to extend the monitor_info category to include
13459 <pre>
13460 - current number of monitors
13461 - enumeration of monitors
13462 - enumeration of threads waiting on a given monitor
13463 </pre>
13464 The reason for my question is the fact that current get_monitor_info support
13465 requires the agent to specify a given thread to get the info which is probably
13466 OK in the profiling/debugging space, while in the monitoring space the agent
13467 could be watching the monitor list and then decide which thread to ask for
13468 the info. You might ask why is this important for monitoring .... I think it
13469 can aid in the detection/prediction of application contention caused by hot-locks.
13470 </intro>
13471 </issuessection>
13472
13473 <changehistory id="ChangeHistory" update="09/05/07">
13474 <intro>
13475 The <jvmti/> specification is an evolving document with major, minor,
13476 and micro version numbers.
13477 A released version of the specification is uniquely identified
13478 by its major and minor version.
13479 The functions, events, and capabilities in this specification
13480 indicate a "Since" value which is the major and minor version in
13481 which it was introduced.
13482 The version of the specification implemented by the VM can
13483 be retrieved at runtime with the <functionlink id="GetVersionNumber"/>
13484 function.
13485 </intro>
13486 <change date="14 Nov 2002">
13487 Converted to XML document.
13488 </change>
13489 <change date="14 Nov 2002">
13490 Elided heap dump functions (for now) since what was there
13491 was wrong.
13492 </change>
13493 <change date="18 Nov 2002">
13494 Added detail throughout.
13495 </change>
13496 <change date="18 Nov 2002">
13497 Changed JVMTI_THREAD_STATUS_RUNNING to JVMTI_THREAD_STATUS_RUNNABLE.
13498 </change>
13499 <change date="19 Nov 2002">
13500 Added AsyncGetStackTrace.
13501 </change>
13502 <change date="19 Nov 2002">
13503 Added jframeID return to GetStackTrace.
13504 </change>
13505 <change date="19 Nov 2002">
13506 Elided GetCurrentFrame and GetCallingFrame functions (for now) since what was there
13507 since they are redundant with GetStackTrace.
13508 </change>
13509 <change date="19 Nov 2002">
13510 Elided ClearAllBreakpoints since it has always been redundant.
13511 </change>
13512 <change date="19 Nov 2002">
13513 Added GetSystemProperties.
13514 </change>
13515 <change date="19 Nov 2002">
13516 Changed the thread local storage functions to use jthread.
13517 </change>
13518 <change date="20 Nov 2002">
13519 Added GetJLocationFormat.
13520 </change>
13521 <change date="22 Nov 2002">
13522 Added events and introductory text.
13523 </change>
13524 <change date="22 Nov 2002">
13525 Cross reference type and constant definitions.
13526 </change>
13527 <change date="24 Nov 2002">
13528 Added DTD.
13529 </change>
13530 <change date="24 Nov 2002">
13531 Added capabilities function section.
13532 </change>
13533 <change date="29 Nov 2002">
13534 Assign capabilities to each function and event.
13535 </change>
13536 <change date="29 Nov 2002">
13537 Add <internallink id="jniIntercept">JNI interception functions</internallink>.
13538 </change>
13539 <change date="30 Nov 2002">
13540 Auto generate SetEventNotificationMode capabilities.
13541 </change>
13542 <change date="30 Nov 2002">
13543 Add <eventlink id="VMObjectAlloc"></eventlink> event.
13544 </change>
13545 <change date="30 Nov 2002">
13546 Add <eventlink id="DynamicCodeGenerated"></eventlink> event.
13547 </change>
13548 <change date="30 Nov 2002">
13549 Add const to declarations.
13550 </change>
13551 <change date="30 Nov 2002">
13552 Change method exit and frame pop to send on exception.
13553 </change>
13554 <change date="1 Dec 2002">
13555 Add ForceGarbageCollection.
13556 </change>
13557 <change date="2 Dec 2002">
13558 Redo Xrun section; clarify GetStackTrace and add example;
13559 Fix width problems; use "agent" consistently.
13560 </change>
13561 <change date="8 Dec 2002">
13562 Remove previous start-up intro.
13563 Add <internallink id="environments"><jvmti/> Environments</internallink>
13564 section.
13565 </change>
13566 <change date="8 Dec 2002">
13567 Add <functionlink id="DisposeEnvironment"></functionlink>.
13568 </change>
13569 <change date="9 Dec 2002">
13570 Numerous minor updates.
13571 </change>
13572 <change date="15 Dec 2002">
13573 Add heap profiling functions added:
13574 get/set annotation, iterate live objects/heap.
13575 Add heap profiling functions place holder added:
13576 heap roots.
13577 Heap profiling event added: object free.
13578 Heap profiling event redesigned: vm object allocation.
13579 Heap profiling event placeholders added: garbage collection start/finish.
13580 Native method bind event added.
13581 </change>
13582 <change date="19 Dec 2002">
13583 Revamp suspend/resume functions.
13584 Add origin information with jvmdi tag.
13585 Misc fixes.
13586 </change>
13587 <change date="24 Dec 2002">
13588 Add semantics to types.
13589 </change>
13590 <change date="27 Dec 2002">
13591 Add local reference section.
13592 Autogenerate parameter descriptions from types.
13593 </change>
13594 <change date="28 Dec 2002">
13595 Document that RunAgentThread sends threadStart.
13596 </change>
13597 <change date="29 Dec 2002">
13598 Remove redundant local ref and dealloc warning.
13599 Convert GetRawMonitorName to allocated buffer.
13600 Add GenerateEvents.
13601 </change>
13602 <change date="30 Dec 2002">
13603 Make raw monitors a type and rename to "jrawMonitorID".
13604 </change>
13605 <change date="1 Jan 2003">
13606 Include origin information.
13607 Clean-up JVMDI issue references.
13608 Remove Deallocate warnings which are now automatically generated.
13609 </change>
13610 <change date="2 Jan 2003">
13611 Fix representation issues for jthread.
13612 </change>
13613 <change date="3 Jan 2003">
13614 Make capabilities buffered out to 64 bits - and do it automatically.
13615 </change>
13616 <change date="4 Jan 2003">
13617 Make constants which are enumeration into enum types.
13618 Parameters now of enum type.
13619 Clean-up and index type section.
13620 Replace remaining datadef entities with callback.
13621 </change>
13622 <change date="7 Jan 2003">
13623 Correct GenerateEvents description.
13624 More internal semantics work.
13625 </change>
13626 <change date="9 Jan 2003">
13627 Replace previous GetSystemProperties with two functions
13628 which use allocated information instead fixed.
13629 Add SetSystemProperty.
13630 More internal semantics work.
13631 </change>
13632 <change date="12 Jan 2003">
13633 Add varargs to end of SetEventNotificationMode.
13634 </change>
13635 <change date="20 Jan 2003">
13636 Finish fixing spec to reflect that alloc sizes are jlong.
13637 </change>
13638 <change date="22 Jan 2003">
13639 Allow NULL as RunAgentThread arg.
13640 </change>
13641 <change date="22 Jan 2003">
13642 Fixed names to standardized naming convention
13643 Removed AsyncGetStackTrace.
13644 </change>
13645 <change date="29 Jan 2003">
13646 Since we are using jthread, removed GetThread.
13647 </change>
13648 <change date="31 Jan 2003">
13649 Change GetFieldName to allow NULLs like GetMethodName.
13650 </change>
13651 <change date="29 Feb 2003" version="v40">
13652 Rewrite the introductory text, adding sections on
13653 start-up, environments and bytecode instrumentation.
13654 Change the command line arguments per EG discussions.
13655 Add an introduction to the capabilities section.
13656 Add the extension mechanism category and functions.
13657 Mark for deletion, but clarified anyhow, SuspendAllThreads.
13658 Rename IterateOverLiveObjects to IterateOverReachableObjects and
13659 change the text accordingly.
13660 Clarify IterateOverHeap.
13661 Clarify CompiledMethodLoad.
13662 Discuss prerequisite state for Calling Functions.
13663 Clarify SetAllocationHooks.
13664 Added issues ("To be resolved:") through-out.
13665 And so on...
13666 </change>
13667 <change date="6 Mar 2003" version="v41">
13668 Remove struct from the call to GetOwnedMonitorInfo.
13669 Automatically generate most error documentation, remove
13670 (rather broken) hand written error doc.
13671 Better describe capability use (empty initial set).
13672 Add min value to jint params.
13673 Remove the capability can_access_thread_local_storage.
13674 Rename error JVMTI_ERROR_NOT_IMPLEMENTED to JVMTI_ERROR_MUST_POSSESS_CAPABILITY;
13675 same for *NOT_IMPLEMENTED.
13676 Description fixes.
13677 </change>
13678 <change date="8 Mar 2003" version="v42">
13679 Rename GetClassSignature to GetClassName.
13680 Rename IterateOverClassObjects to IterateOverInstancesOfClass.
13681 Remove GetMaxStack (operand stack isn't used in <jvmti/>).
13682 Description fixes: define launch-time, remove native frame pop
13683 from PopFrame, and assorted clarifications.
13684 </change>
13685 <change date="8 Mar 2003" version="v43">
13686 Fix minor editing problem.
13687 </change>
13688 <change date="10 Mar 2003" version="v44">
13689 Add phase information.
13690 Remap (compact) event numbers.
13691 </change>
13692 <change date="11 Mar 2003" version="v45">
13693 More phase information - allow "any".
13694 Elide raw monitor queries and events.
13695 Minor description fixes.
13696 </change>
13697 <change date="12 Mar 2003" version="v46">
13698 Add GetPhase.
13699 Use "phase" through document.
13700 Elide GetRawMonitorName.
13701 Elide GetObjectMonitors.
13702 </change>
13703 <change date="12 Mar 2003" version="v47">
13704 Fixes from link, XML, and spell checking.
13705 Auto-generate the callback structure.
13706 </change>
13707 <change date="13 Mar 2003" version="v48">
13708 One character XML fix.
13709 </change>
13710 <change date="13 Mar 2003" version="v49">
13711 Change function parameter names to be consistent with
13712 event parameters (fooBarBaz becomes foo_bar_baz).
13713 </change>
13714 <change date="14 Mar 2003" version="v50">
13715 Fix broken link. Fix thread markers.
13716 </change>
13717 <change date="14 Mar 2003" version="v51">
13718 Change constants so they are under 128 to workaround
13719 compiler problems.
13720 </change>
13721 <change date="23 Mar 2003" version="v52">
13722 Overhaul capabilities. Separate GetStackTrace into
13723 GetStackTrace and GetStackFrames.
13724 </change>
13725 <change date="8 Apr 2003" version="v54">
13726 Use depth instead of jframeID to reference frames.
13727 Remove the now irrelevant GetCurrentFrame, GetCallerFrame and GetStackFrames.
13728 Remove frame arg from events.
13729 </change>
13730 <change date="9 Apr 2003" version="v55">
13731 Remove GetObjectWithAnnotation since tests show bufferred approach more efficient.
13732 Add missing annotation_count to GetObjectsWithAnnotations
13733 </change>
13734 <change date="10 Apr 2003" version="v56">
13735 Remove confusing parenthetical statement in GetObjectsWithAnnotations
13736 </change>
13737 <change date="13 Apr 2003" version="v58">
13738 Replace jclass/jmethodID representation of method with simply jmethodID;
13739 Pass JvmtiEnv* as first arg of every event; remove JNIEnv* where inappropriate.
13740 Replace can_access_frames with can_access_local_variables; remove from purely stack access.
13741 Use can_get_synthetic_attribute; fix description.
13742 Clarify that zero length arrays must be deallocated.
13743 Clarify RelinquishCapabilities.
13744 Generalize JVMTI_ERROR_VM_DEAD to JVMTI_ERROR_WRONG_PHASE.
13745 </change>
13746 <change date="27 Apr 2003" version="v59">
13747 Remove lingering indirect references to OBSOLETE_METHOD_ID.
13748 </change>
13749 <change date="4 May 2003" version="v60">
13750 Allow DestroyRawMonitor during OnLoad.
13751 </change>
13752 <change date="7 May 2003" version="v61">
13753 Added not monitor owner error return to DestroyRawMonitor.
13754 </change>
13755 <change date="13 May 2003" version="v62">
13756 Clarify semantics of raw monitors.
13757 Change flags on <code>GetThreadStatus</code>.
13758 <code>GetClassLoader</code> return NULL for the bootstrap class loader.
13759 Add <code>GetClassName</code> issue.
13760 Define local variable signature.
13761 Disallow zero in annotations array of <code>GetObjectsWithAnnotations</code>.
13762 Remove over specification in <code>GetObjectsWithAnnotations</code>.
13763 Elide <code>SetAllocationHooks</code>.
13764 Elide <code>SuspendAllThreads</code>.
13765 </change>
13766 <change date="14 May 2003" version="v63">
13767 Define the data type <code>jvmtiEventCallbacks</code>.
13768 Zero length allocations return NULL.
13769 Keep SetAllocationHooks in JVMDI, but remove from <jvmti/>.
13770 Add JVMTI_THREAD_STATUS_FLAG_INTERRUPTED.
13771 </change>
13772 <change date="15 May 2003" version="v64">
13773 Better wording, per review.
13774 </change>
13775 <change date="15 May 2003" version="v65">
13776 First Alpha.
13777 Make jmethodID and jfieldID unique, jclass not used.
13778 </change>
13779 <change date="27 May 2003" version="v66">
13780 Fix minor XSLT errors.
13781 </change>
13782 <change date="13 June 2003" version="v67">
13783 Undo making jfieldID unique (jmethodID still is).
13784 </change>
13785 <change date="17 June 2003" version="v68">
13786 Changes per June 11th Expert Group meeting --
13787 Overhaul Heap functionality: single callback,
13788 remove GetHeapRoots, add reachable iterators,
13789 and rename "annotation" to "tag".
13790 NULL thread parameter on most functions is current
13791 thread.
13792 Add timers.
13793 Remove ForceExit.
13794 Add GetEnvironmentLocalStorage.
13795 Add verbose flag and event.
13796 Add AddToBootstrapClassLoaderSearch.
13797 Update ClassFileLoadHook.
13798 </change>
13799 <change date="18 June 2003" version="v69">
13800 Clean up issues sections.
13801 Rename GetClassName back to GetClassSignature and
13802 fix description.
13803 Add generic signature to GetClassSignature,
13804 GetFieldSignature, GetMethodSignature, and
13805 GetLocalVariableTable.
13806 Elide EstimateCostOfCapabilities.
13807 Clarify that the system property functions operate
13808 on the VM view of system properties.
13809 Clarify Agent_OnLoad.
13810 Remove "const" from JNIEnv* in events.
13811 Add metadata accessors.
13812 </change>
13813 <change date="18 June 2003" version="v70">
13814 Add start_depth to GetStackTrace.
13815 Move system properties to a new category.
13816 Add GetObjectSize.
13817 Remove "X" from command line flags.
13818 XML, HTML, and spell check corrections.
13819 </change>
13820 <change date="19 June 2003" version="v71">
13821 Fix JVMTI_HEAP_ROOT_THREAD to be 6.
13822 Make each synopsis match the function name.
13823 Fix unclear wording.
13824 </change>
13825 <change date="26 June 2003" version="v72">
13826 SetThreadLocalStorage and SetEnvironmentLocalStorage should allow value
13827 to be set to NULL.
13828 NotifyFramePop, GetFrameLocationm and all the local variable operations
13829 needed to have their wording about frames fixed.
13830 Grammar and clarity need to be fixed throughout.
13831 Capitalization and puntuation need to be consistent.
13832 Need micro version number and masks for accessing major, minor, and micro.
13833 The error code lists should indicate which must be returned by
13834 an implementation.
13835 The command line properties should be visible in the properties functions.
13836 Disallow popping from the current thread.
13837 Allow implementations to return opaque frame error when they cannot pop.
13838 The NativeMethodBind event should be sent during any phase.
13839 The DynamicCodeGenerated event should be sent during any phase.
13840 The following functions should be allowed to operate before VMInit:
13841 Set/GetEnvironmentLocalStorage
13842 GetMethodDeclaringClass
13843 GetClassSignature
13844 GetClassModifiers
13845 IsInterface
13846 IsArrayClass
13847 GetMethodName
13848 GetMethodModifiers
13849 GetMaxLocals
13850 GetArgumentsSize
13851 GetLineNumberTable
13852 GetMethodLocation
13853 IsMethodNative
13854 IsMethodSynthetic.
13855 Other changes (to XSL):
13856 Argument description should show asterisk after not before pointers.
13857 NotifyFramePop, GetFrameLocationm and all the local variable operations
13858 should hsve the NO_MORE_FRAMES error added.
13859 Not alive threads should have a different error return than invalid thread.
13860 </change>
13861 <change date="7 July 2003" version="v73">
13862 VerboseOutput event was missing message parameter.
13863 Minor fix-ups.
13864 </change>
13865 <change date="14 July 2003" version="v74">
13866 Technical Publications Department corrections.
13867 Allow thread and environment local storage to be set to NULL.
13868 </change>
13869 <change date="23 July 2003" version="v75">
13870 Use new Agent_OnLoad rather than overloaded JVM_OnLoad.
13871 Add JNICALL to callbacks (XSL).
13872 Document JNICALL requirement for both events and callbacks (XSL).
13873 Restrict RedefineClasses to methods and attributes.
13874 Elide the VerboseOutput event.
13875 VMObjectAlloc: restrict when event is sent and remove method parameter.
13876 Finish loose ends from Tech Pubs edit.
13877 </change>
13878 <change date="24 July 2003" version="v76">
13879 Change ClassFileLoadHook event to send the class instead of a boolean of redefine.
13880 </change>
13881 <change date="24 July 2003" version="v77">
13882 XML fixes.
13883 Minor text clarifications and corrections.
13884 </change>
13885 <change date="24 July 2003" version="v78">
13886 Remove GetExceptionHandlerTable and GetThrownExceptions from <jvmti/>.
13887 Clarify that stack frames are JVM Spec frames.
13888 Split can_get_source_info into can_get_source_file_name, can_get_line_numbers,
13889 and can_get_source_debug_extension.
13890 PopFrame cannot have a native calling method.
13891 Removed incorrect statement in GetClassloaderClasses
13892 (see <vmspec chapter="4.4"/>).
13893 </change>
13894 <change date="24 July 2003" version="v79">
13895 XML and text fixes.
13896 Move stack frame description into Stack Frame category.
13897 </change>
13898 <change date="26 July 2003" version="v80">
13899 Allow NULL (means bootstrap loader) for GetClassloaderClasses.
13900 Add new heap reference kinds for references from classes.
13901 Add timer information struct and query functions.
13902 Add AvailableProcessors.
13903 Rename GetOtherThreadCpuTime to GetThreadCpuTime.
13904 Explicitly add JVMTI_ERROR_INVALID_THREAD and JVMTI_ERROR_THREAD_NOT_ALIVE
13905 to SetEventNotification mode.
13906 Add initial thread to the VM_INIT event.
13907 Remove platform assumptions from AddToBootstrapClassLoaderSearch.
13908 </change>
13909 <change date="26 July 2003" version="v81">
13910 Grammar and clarity changes per review.
13911 </change>
13912 <change date="27 July 2003" version="v82">
13913 More grammar and clarity changes per review.
13914 Add Agent_OnUnload.
13915 </change>
13916 <change date="28 July 2003" version="v83">
13917 Change return type of Agent_OnUnload to void.
13918 </change>
13919 <change date="28 July 2003" version="v84">
13920 Rename JVMTI_REFERENCE_ARRAY to JVMTI_REFERENCE_ARRAY_ELEMENT.
13921 </change>
13922 <change date="28 July 2003" version="v85">
13923 Steal java.lang.Runtime.availableProcessors() wording for
13924 AvailableProcessors().
13925 Guarantee that zero will never be an event ID.
13926 Remove some issues which are no longer issues.
13927 Per review, rename and more completely document the timer
13928 information functions.
13929 </change>
13930 <change date="29 July 2003" version="v86">
13931 Non-spec visible change to XML controlled implementation:
13932 SetThreadLocalStorage must run in VM mode.
13933 </change>
13934 <change date="5 August 2003" version="0.1.87">
13935 Add GetErrorName.
13936 Add varargs warning to jvmtiExtensionEvent.
13937 Remove "const" on the jvmtiEnv* of jvmtiExtensionEvent.
13938 Remove unused can_get_exception_info capability.
13939 Pass jvmtiEnv* and JNIEnv* to the jvmtiStartFunction.
13940 Fix jvmtiExtensionFunctionInfo.func declared type.
13941 Extension function returns error code.
13942 Use new version numbering.
13943 </change>
13944 <change date="5 August 2003" version="0.2.88">
13945 Remove the ClassUnload event.
13946 </change>
13947 <change date="8 August 2003" version="0.2.89">
13948 Heap reference iterator callbacks return an enum that
13949 allows outgoing object references to be ignored.
13950 Allow JNIEnv as a param type to extension events/functions.
13951 </change>
13952 <change date="15 August 2003" version="0.2.90">
13953 Fix a typo.
13954 </change>
13955 <change date="2 September 2003" version="0.2.91">
13956 Remove all metadata functions: GetClassMetadata,
13957 GetFieldMetadata, and GetMethodMetadata.
13958 </change>
13959 <change date="1 October 2003" version="0.2.92">
13960 Mark the functions Allocate. Deallocate, RawMonitor*,
13961 SetEnvironmentLocalStorage, and GetEnvironmentLocalStorage
13962 as safe for use in heap callbacks and GC events.
13963 </change>
13964 <change date="24 November 2003" version="0.2.93">
13965 Add pass through opaque user data pointer to heap iterate
13966 functions and callbacks.
13967 In the CompiledMethodUnload event, send the code address.
13968 Add GarbageCollectionOccurred event.
13969 Add constant pool reference kind.
13970 Mark the functions CreateRawMonitor and DestroyRawMonitor
13971 as safe for use in heap callbacks and GC events.
13972 Clarify: VMDeath, GetCurrentThreadCpuTimerInfo,
13973 GetThreadCpuTimerInfo, IterateOverReachableObjects,
13974 IterateOverObjectsReachableFromObject, GetTime and
13975 JVMTI_ERROR_NULL_POINTER.
13976 Add missing errors to: GenerateEvents and
13977 AddToBootstrapClassLoaderSearch.
13978 Fix description of ClassFileLoadHook name parameter.
13979 In heap callbacks and GC/ObjectFree events, specify
13980 that only explicitly allowed functions can be called.
13981 Allow GetCurrentThreadCpuTimerInfo, GetCurrentThreadCpuTime,
13982 GetTimerInfo, and GetTime during callback.
13983 Allow calling SetTag/GetTag during the onload phase.
13984 SetEventNotificationMode, add: error attempted inappropriate
13985 thread level control.
13986 Remove jvmtiExceptionHandlerEntry.
13987 Fix handling of native methods on the stack --
13988 location_ptr param of GetFrameLocation, remove
13989 JVMTI_ERROR_OPAQUE_FRAME from GetFrameLocation,
13990 jvmtiFrameInfo.location, and jlocation.
13991 Remove typo (from JVMPI) implying that the MonitorWaited
13992 event is sent on sleep.
13993 </change>
13994 <change date="25 November 2003" version="0.2.94">
13995 Clarifications and typos.
13996 </change>
13997 <change date="3 December 2003" version="0.2.95">
13998 Allow NULL user_data in heap iterators.
13999 </change>
14000 <change date="28 January 2004" version="0.2.97">
14001 Add GetThreadState, deprecate GetThreadStatus.
14002 </change>
14003 <change date="29 January 2004" version="0.2.98">
14004 INVALID_SLOT and TYPE_MISMATCH errors should be optional.
14005 </change>
14006 <change date="12 February 2004" version="0.2.102">
14007 Remove MonitorContendedExit.
14008 Added JNIEnv parameter to VMObjectAlloc.
14009 Clarified definition of class_tag and referrer_index
14010 parameters to heap callbacks.
14011 </change>
14012 <change date="16 Febuary 2004" version="0.2.103">
14013 Document JAVA_TOOL_OPTIONS.
14014 </change>
14015 <change date="17 Febuary 2004" version="0.2.105">
14016 Divide start phase into primordial and start.
14017 Add VMStart event
14018 Change phase associations of functions and events.
14019 </change>
14020 <change date="18 Febuary 2004" version="0.3.6">
14021 Elide deprecated GetThreadStatus.
14022 Bump minor version, subtract 100 from micro version
14023 </change>
14024 <change date="18 Febuary 2004" version="0.3.7">
14025 Document that timer nanosecond values are unsigned.
14026 Clarify text having to do with native methods.
14027 </change>
14028 <change date="19 Febuary 2004" version="0.3.8">
14029 Fix typos.
14030 Remove elided deprecated GetThreadStatus.
14031 </change>
14032 <change date="23 Febuary 2004" version="0.3.9">
14033 Require NotifyFramePop to act on suspended threads.
14034 </change>
14035 <change date="24 Febuary 2004" version="0.3.10">
14036 Add capabilities
14037 (<internallink id="jvmtiCapabilities.can_redefine_any_class"
14038 ><code>can_redefine_any_class</code></internallink>
14039 and
14040 <internallink id="jvmtiCapabilities.can_generate_all_class_hook_events"
14041 ><code>can_generate_all_class_hook_events</code></internallink>)
14042 and an error (<errorlink id="JVMTI_ERROR_UNMODIFIABLE_CLASS"></errorlink>)
14043 which allow some classes to be unmodifiable.
14044 </change>
14045 <change date="28 Febuary 2004" version="0.3.11">
14046 Add JVMTI_ERROR_MUST_POSSESS_CAPABILITY to SetEventNotificationMode.
14047 </change>
14048 <change date="8 March 2004" version="0.3.12">
14049 Clarified CompiledMethodUnload so that it is clear the event
14050 may be posted after the class has been unloaded.
14051 </change>
14052 <change date="5 March 2004" version="0.3.13">
14053 Change the size parameter of VMObjectAlloc to jlong to match GetObjectSize.
14054 </change>
14055 <change date="13 March 2004" version="0.3.14">
14056 Added guideline for the use of the JNI FindClass function in event
14057 callback functions.
14058 </change>
14059 <change date="15 March 2004" version="0.3.15">
14060 Add GetAllStackTraces and GetThreadListStackTraces.
14061 </change>
14062 <change date="19 March 2004" version="0.3.16">
14063 ClassLoad and ClassPrepare events can be posted during start phase.
14064 </change>
14065 <change date="25 March 2004" version="0.3.17">
14066 Add JVMTI_ERROR_NATIVE_METHOD to GetLineNumberTable, GetLocalVariableTable,
14067 GetMaxLocals, GetArgumentsSize, GetMethodLocation, GetBytecodes.
14068 </change>
14069 <change date="29 March 2004" version="0.3.18">
14070 Return the timer kind in the timer information structure.
14071 </change>
14072 <change date="31 March 2004" version="0.3.19">
14073 Spec clarifications:
14074 JVMTI_THREAD_STATE_IN_NATIVE might not include JNI or <jvmti/>.
14075 ForceGarbageCollection does not run finalizers.
14076 The context of the specification is the Java platform.
14077 Warn about early instrumentation.
14078 </change>
14079 <change date="1 April 2004" version="0.3.20">
14080 Refinements to the above clarifications and
14081 Clarify that an error returned by Agent_OnLoad terminates the VM.
14082 </change>
14083 <change date="1 April 2004" version="0.3.21">
14084 Array class creation does not generate a class load event.
14085 </change>
14086 <change date="7 April 2004" version="0.3.22">
14087 Align thread state hierarchy more closely with java.lang.Thread.State.
14088 </change>
14089 <change date="12 April 2004" version="0.3.23">
14090 Clarify the documentation of thread state.
14091 </change>
14092 <change date="19 April 2004" version="0.3.24">
14093 Remove GarbageCollectionOccurred event -- can be done by agent.
14094 </change>
14095 <change date="22 April 2004" version="0.3.25">
14096 Define "command-line option".
14097 </change>
14098 <change date="29 April 2004" version="0.3.26">
14099 Describe the intended use of bytecode instrumentation.
14100 Fix description of extension event first parameter.
14101 </change>
14102 <change date="30 April 2004" version="0.3.27">
14103 Clarification and typos.
14104 </change>
14105 <change date="18 May 2004" version="0.3.28">
14106 Remove DataDumpRequest event.
14107 </change>
14108 <change date="18 May 2004" version="0.3.29">
14109 Clarify RawMonitorWait with zero timeout.
14110 Clarify thread state after RunAgentThread.
14111 </change>
14112 <change date="24 May 2004" version="0.3.30">
14113 Clean-up: fix bad/old links, etc.
14114 </change>
14115 <change date="30 May 2004" version="0.3.31">
14116 Clarifications including:
14117 All character strings are modified UTF-8.
14118 Agent thread visibiity.
14119 Meaning of obsolete method version.
14120 Thread invoking heap callbacks,
14121 </change>
14122 <change date="1 June 2004" version="1.0.32">
14123 Bump major.minor version numbers to "1.0".
14124 </change>
14125 <change date="2 June 2004" version="1.0.33">
14126 Clarify interaction between ForceGarbageCollection
14127 and ObjectFree.
14128 </change>
14129 <change date="6 June 2004" version="1.0.34">
14130 Restrict AddToBootstrapClassLoaderSearch and
14131 SetSystemProperty to the OnLoad phase only.
14132 </change>
14133 <change date="11 June 2004" version="1.0.35">
14134 Fix typo in SetTag.
14135 </change>
14136 <change date="18 June 2004" version="1.0.36">
14137 Fix trademarks.
14138 Add missing parameter in example GetThreadState usage.
14139 </change>
14140 <change date="4 August 2004" version="1.0.37">
14141 Copyright updates.
14142 </change>
14143 <change date="5 November 2004" version="1.0.38">
14144 Add missing function table layout.
14145 Add missing description of C++ member function format of functions.
14146 Clarify that name in CFLH can be NULL.
14147 Released as part of <tm>J2SE</tm> 5.0.
14148 </change>
14149 <change date="24 April 2005" version="1.1.47">
14150 Bump major.minor version numbers to "1.1".
14151 Add ForceEarlyReturn* functions.
14152 Add GetOwnedMonitorStackDepthInfo function.
14153 Add GetCurrentThread function.
14154 Add "since" version marker.
14155 Add AddToSystemClassLoaderSearch.
14156 Allow AddToBootstrapClassLoaderSearch be used in live phase.
14157 Fix historic rubbish in the descriptions of the heap_object_callback
14158 parameter of IterateOverHeap and IterateOverInstancesOfClass functions;
14159 disallow NULL for this parameter.
14160 Clarify, correct and make consistent: wording about current thread,
14161 opaque frames and insufficient number of frames in PopFrame.
14162 Consistently use "current frame" rather than "topmost".
14163 Clarify the JVMTI_ERROR_TYPE_MISMATCH errors in GetLocal* and SetLocal*
14164 by making them compatible with those in ForceEarlyReturn*.
14165 Many other clarifications and wording clean ups.
14166 </change>
14167 <change date="25 April 2005" version="1.1.48">
14168 Add GetConstantPool.
14169 Switch references to the first edition of the VM Spec, to the seconds edition.
14170 </change>
14171 <change date="26 April 2005" version="1.1.49">
14172 Clarify minor/major version order in GetConstantPool.
14173 </change>
14174 <change date="26 April 2005" version="1.1.50">
14175 Add SetNativeMethodPrefix and SetNativeMethodPrefixes.
14176 Reassign GetOwnedMonitorStackDepthInfo to position 153.
14177 Break out Class Loader Search in its own documentation category.
14178 Deal with overly long lines in XML source.
14179 </change>
14180 <change date="29 April 2005" version="1.1.51">
14181 Allow agents be started in the live phase.
14182 Added paragraph about deploying agents.
14183 </change>
14184 <change date="30 April 2005" version="1.1.52">
14185 Add specification description to SetNativeMethodPrefix(es).
14186 Better define the conditions on GetConstantPool.
14187 </change>
14188 <change date="30 April 2005" version="1.1.53">
14189 Break out the GetClassVersionNumber function from GetConstantPool.
14190 Clean-up the references to the VM Spec.
14191 </change>
14192 <change date="1 May 2005" version="1.1.54">
14193 Allow SetNativeMethodPrefix(es) in any phase.
14194 Add clarifications about the impact of redefinition on GetConstantPool.
14195 </change>
14196 <change date="2 May 2005" version="1.1.56">
14197 Various clarifications to SetNativeMethodPrefix(es).
14198 </change>
14199 <change date="2 May 2005" version="1.1.57">
14200 Add missing performance warning to the method entry event.
14201 </change>
14202 <change date="5 May 2005" version="1.1.58">
14203 Remove internal JVMDI support.
14204 </change>
14205 <change date="8 May 2005" version="1.1.59">
14206 Add <functionlink id="RetransformClasses"/>.
14207 Revamp the bytecode instrumentation documentation.
14208 Change <functionlink id="IsMethodObsolete"/> to no longer
14209 require the can_redefine_classes capability.
14210 </change>
14211 <change date="11 May 2005" version="1.1.63">
14212 Clarifications for retransformation.
14213 </change>
14214 <change date="11 May 2005" version="1.1.64">
14215 Clarifications for retransformation, per review.
14216 Lock "retransformation (in)capable" at class load enable time.
14217 </change>
14218 <change date="4 June 2005" version="1.1.67">
14219 Add new heap functionity which supports reporting primitive values,
14220 allows setting the referrer tag, and has more powerful filtering:
14221 FollowReferences, IterateThroughHeap, and their associated
14222 callbacks, structs, enums, and constants.
14223 </change>
14224 <change date="4 June 2005" version="1.1.68">
14225 Clarification.
14226 </change>
14227 <change date="6 June 2005" version="1.1.69">
14228 FollowReferences, IterateThroughHeap: Put callbacks in a struct;
14229 Add missing error codes; reduce bits in the visit control flags.
14230 </change>
14231 <change date="14 June 2005" version="1.1.70">
14232 More on new heap functionity: spec clean-up per review.
14233 </change>
14234 <change date="15 June 2005" version="1.1.71">
14235 More on new heap functionity: Rename old heap section to Heap (1.0).
14236 </change>
14237 <change date="21 June 2005" version="1.1.72">
14238 Fix typos.
14239 </change>
14240 <change date="27 June 2005" version="1.1.73">
14241 Make referrer info structure a union.
14242 </change>
14243 <change date="9 September 2005" version="1.1.74">
14244 In new heap functions:
14245 Add missing superclass reference kind.
14246 Use a single scheme for computing field indexes.
14247 Remove outdated references to struct based referrer info.
14248 </change>
14249 <change date="12 September 2005" version="1.1.75">
14250 Don't callback during FollowReferences on frivolous java.lang.Object superclass.
14251 </change>
14252 <change date="13 September 2005" version="1.1.76">
14253 In string primitive callback, length now Unicode length.
14254 In array and string primitive callbacks, value now "const".
14255 Note possible compiler impacts on setting JNI function table.
14256 </change>
14257 <change date="13 September 2005" version="1.1.77">
14258 GetClassVersionNumbers() and GetConstantPool() should return
14259 error on array or primitive class.
14260 </change>
14261 <change date="14 September 2005" version="1.1.78">
14262 Grammar fixes.
14263 </change>
14264 <change date="26 September 2005" version="1.1.79">
14265 Add IsModifiableClass query.
14266 </change>
14267 <change date="9 February 2006" version="1.1.81">
14268 Add referrer_class_tag parameter to jvmtiHeapReferenceCallback.
14269 </change>
14270 <change date="13 February 2006" version="1.1.82">
14271 Doc fixes: update can_redefine_any_class to include retransform.
14272 Clarify that exception events cover all Throwables.
14273 In GetStackTrace, no test is done for start_depth too big if start_depth is zero,
14274 Clarify fields reported in Primitive Field Callback -- static vs instance.
14275 Repair confusing names of heap types, including callback names.
14276 Require consistent usage of stack depth in the face of thread launch methods.
14277 Note incompatibility of <jvmti/> memory management with other systems.
14278 </change>
14279 <change date="14 February 2006" version="1.1.85">
14280 Fix typos and missing renames.
14281 </change>
14282 <change date="13 March 2006" version="1.1.86">
14283 Clarify that jmethodIDs and jfieldIDs can be saved.
14284 Clarify that Iterate Over Instances Of Class includes subclasses.
14285 </change>
14286 <change date="14 March 2006" version="1.1.87">
14287 Better phrasing.
14288 </change>
14289 <change date="16 March 2006" version="1.1.88">
14290 Match the referrer_index for static fields in Object Reference Callback
14291 with the Reference Implementation (and all other known implementations);
14292 that is, make it match the definition for instance fields.
14293 In GetThreadListStackTraces, add JVMTI_ERROR_INVALID_THREAD to cover
14294 an invalid thread in the list; and specify that not started threads
14295 return empty stacks.
14296 </change>
14297 <change date="17 March 2006" version="1.1.89">
14298 Typo.
14299 </change>
14300 <change date="25 March 2006" version="1.1.90">
14301 Typo.
14302 </change>
14303 <change date="6 April 2006" version="1.1.91">
14304 Remove restrictions on AddToBootstrapClassLoaderSearch and
14305 AddToSystemClassLoaderSearch.
14306 </change>
14307 <change date="1 May 2006" version="1.1.93">
14308 Changed spec to return -1 for monitor stack depth for the
14309 implementation which can not determine stack depth.
14310 </change>
14311 <change date="3 May 2006" version="1.1.94">
14312 Corrections for readability and accuracy courtesy of Alan Pratt of IBM.
14313 List the object relationships reported in FollowReferences.
14314 </change>
14315 <change date="5 May 2006" version="1.1.95">
14316 Clarify the object relationships reported in FollowReferences.
14317 </change>
14318 <change date="28 June 2006" version="1.1.98">
14319 Clarify DisposeEnvironment; add warning.
14320 Fix typos in SetLocalXXX "retrieve" => "set".
14321 Clarify that native method prefixes must remain set while used.
14322 Clarify that exactly one Agent_OnXXX is called per agent.
14323 Clarify that library loading is independent from start-up.
14324 Remove ambiguous reference to Agent_OnLoad in the Agent_OnUnload spec.
14325 </change>
14326 <change date="31 July 2006" version="1.1.99">
14327 Clarify the interaction between functions and exceptions.
14328 Clarify and give examples of field indices.
14329 Remove confusing "That is" sentence from MonitorWait and MonitorWaited events.
14330 Update links to point to Java 6.
14331 </change>
14332 <change date="6 August 2006" version="1.1.102">
14333 Add ResourceExhaustedEvent.
14334 </change>
14335 <change date="11 October 2012" version="1.2.2">
14336 Fixed the "HTTP" and "Missing Anchor" errors reported by the LinkCheck tool.
14337 </change>
14338 <change date="19 June 2013" version="1.2.3">
14339 Added support for statically linked agents.
14340 </change>
14341 </changehistory>
14342
14343 </specification>
14344 <!-- Keep this comment at the end of the file
14345 Local variables:
14346 mode: sgml
14347 sgml-omittag:t
14348 sgml-shorttag:t
14349 sgml-namecase-general:t
14350 sgml-general-insert-case:lower
14351 sgml-minimize-attributes:nil
14352 sgml-always-quote-attributes:t
14353 sgml-indent-step:2
14354 sgml-indent-data:t
14355 sgml-parent-document:nil
14356 sgml-exposed-tags:nil
14357 sgml-local-catalogs:nil
14358 sgml-local-ecat-files:nil
14359 End:
14360 -->