1JCMD(1) JDK Commands JCMD(1)
2
6 jcmd - send diagnostic command requests to a running Java Virtual Ma‐
7 chine (JVM)
8
10 jcmd [pid | main-class] command... | PerfCounter.print | -f filename
11 jcmd [-l]
13 jcmd -h
15 pid When used, the jcmd utility sends the diagnostic command request
17 to the process ID for the Java process.
18 main-class
20 When used, the jcmd utility sends the diagnostic command request
21 to all Java processes with the specified name of the main class.
22 command
24 The command must be a valid jcmd command for the selected JVM.
25 The list of available commands for jcmd is obtained by running
26 the help command (jcmd pid help) where pid is the process ID for
27 the running Java process. If the pid is 0, commands will be
28 sent to all Java processes. The main class argument will be
29 used to match, either partially or fully, the class used to
30 start Java. If no options are given, it lists the running Java
31 process identifiers with the main class and command-line argu‐
32 ments that were used to launch the process (the same as using
33 -l).
34 Perfcounter.print
36 Prints the performance counters exposed by the specified Java
37 process.
38 -f filename
40 Reads and executes commands from a specified file, filename.
41 -l Displays the list of Java Virtual Machine process identifiers
43 that are not running in a separate docker process along with the
44 main class and command-line arguments that were used to launch
45 the process. If the JVM is in a docker process, you must use
46 tools such as ps to look up the PID.
47 Note:
49 Using jcmd without arguments is the same as using jcmd -l.
51 -h Displays the jcmd utility's command-line help.
53
55 The jcmd utility is used to send diagnostic command requests to the
56 JVM. It must be used on the same machine on which the JVM is running,
57 and have the same effective user and group identifiers that were used
58 to launch the JVM. Each diagnostic command has its own set of argu‐
59 ments. To display the description, syntax, and a list of available ar‐
60 guments for a diagnostic command, use the name of the command as the
61 argument. For example:
62 jcmd pid help command
64 If arguments contain spaces, then you must surround them with single or
66 double quotation marks (' or "). In addition, you must escape single
67 or double quotation marks with a backslash (\) to prevent the operating
68 system shell from processing quotation marks. Alternatively, you can
69 surround these arguments with single quotation marks and then with dou‐
70 ble quotation marks (or with double quotation marks and then with sin‐
71 gle quotation marks).
72 If you specify the process identifier (pid) or the main class
74 (main-class) as the first argument, then the jcmd utility sends the di‐
75 agnostic command request to the Java process with the specified identi‐
76 fier or to all Java processes with the specified name of the main
77 class. You can also send the diagnostic command request to all avail‐
78 able Java processes by specifying 0 as the process identifier.
79
81 The command must be a valid jcmd diagnostic command for the selected
82 JVM. The list of available commands for jcmd is obtained by running
83 the help command (jcmd pid help) where pid is the process ID for a run‐
84 ning Java process. If the pid is 0, commands will be sent to all Java
85 processes. The main class argument will be used to match, either par‐
86 tially or fully, the class used to start Java. If no options are giv‐
87 en, it lists the running Java process identifiers that are not in sepa‐
88 rate docker processes along with the main class and command-line argu‐
89 ments that were used to launch the process (the same as using -l).
90 The following commands are available:
92 help [options] [arguments]
94 For more information about a specific command.
95 arguments:
97 · command name: The name of the command for which we want help
99 (STRING, no default value)
100 Note:
102 The following options must be specified using either key or
104 key=value syntax.
105 options:
107 · -all: (Optional) Show help for all commands (BOOLEAN, false) .
109 Compiler.codecache
111 Prints code cache layout and bounds.
112 Impact: Low
114 Permission: java.lang.management.ManagementPermission(monitor)
116 Compiler.codelist
118 Prints all compiled methods in code cache that are alive.
119 Impact: Medium
121 Permission: java.lang.management.ManagementPermission(monitor)
123 Compiler.queue
125 Prints methods queued for compilation.
126 Impact: Low
128 Permission: java.lang.management.ManagementPermission(monitor)
130 Compiler.directives_add *filename* *arguments*
132 Adds compiler directives from a file.
133 Impact: Low
135 Permission: java.lang.management.ManagementPermission(monitor)
137 arguments:
139 filename: The name of the directives file (STRING, no default
141 value)
142 Compiler.directives_clear
144 Remove all compiler directives.
145 Impact: Low
147 Permission: java.lang.management.ManagementPermission(monitor)
149 Compiler.directives_print
151 Prints all active compiler directives.
152 Impact: Low
154 Permission: java.lang.management.ManagementPermission(monitor)
156 Compiler.directives_remove
158 Remove latest added compiler directive.
159 Impact: Low
161 Permission: java.lang.management.ManagementPermission(monitor)
163 GC.class_histogram [options]
165 Provides statistics about the Java heap usage.
166 Impact: High --- depends on Java heap size and content.
168 Permission: java.lang.management.ManagementPermission(monitor)
170 Note:
172 The options must be specified using either key or key=value syn‐
174 tax.
175 options:
177 · -all: (Optional) Inspects all objects, including unreachable
179 objects (BOOLEAN, false)
180 GC.class_stats [options] [arguments]
182 (Deprecated) Provide statistics about Java class meta data.
183 Impact: High --- depends on Java heap size and content.
185 Note:
187 The options must be specified using either key or key=value syn‐
189 tax.
190 options:
192 · -all: (Optional) Shows all columns (BOOLEAN, false)
194 · -csv: (Optional) Prints in CSV (comma-separated values) format
196 for spreadsheets (BOOLEAN, false)
197 · -help: (Optional) Shows the meaning of all the columns (BOOL‐
199 EAN, false)
200 arguments:
202 · columns: (Optional) Comma-separated list of all the columns to
204 be shown. If not specified, the following columns are shown:
205 · InstBytes
207 · KlassBytes
209 · CpAll
211 · annotations
213 · MethodCount
215 · Bytecodes
217 · MethodAll
219 · ROAll
221 · RWAll
223 · Total
225 (STRING, no default value)
227 GC.finalizer_info
229 Provides information about the Java finalization queue.
230 Impact: Medium
232 Permission: java.lang.management.ManagementPermission(monitor)
234 GC.heap_dump [options] [arguments]
236 Generates a HPROF format dump of the Java heap.
237 Impact: High --- depends on the Java heap size and content. Re‐
239 quest a full GC unless the -all option is specified.
240 Permission: java.lang.management.ManagementPermission(monitor)
242 Note:
244 The following options must be specified using either key or
246 key=value syntax.
247 options:
249 · -all: (Optional) Dump all objects, including unreachable ob‐
251 jects (BOOLEAN, false)
252 arguments:
254 · filename: The name of the dump file (STRING, no default value)
256 GC.heap_info
258 Provides generic Java heap information.
259 Impact: Medium
261 Permission: java.lang.management.ManagementPermission(monitor)
263 GC.run Calls java.lang.System.gc().
265 Impact: Medium --- depends on the Java heap size and content.
267 GC.run_finalization
269 Calls java.lang.System.runFinalization().
270 Impact: Medium --- depends on the Java content.
272 JFR.check [options]
274 Show information about a running flight recording
275 Impact: Low
277 Note:
279 The options must be specified using either key or key=value syn‐
281 tax. If no parameters are entered, information for all active
282 recordings is shown.
283 options:
285 · name: (Optional) Name of the flight recording. (STRING, no
287 default value)
288 · verbose: (Optional) Flag for printing the event settings for
290 the recording (BOOLEAN, false)
291 JFR.configure [options]
293 Set the parameters for a flight recording
294 Impact: Low
296 Note:
298 The options must be specified using either key or key=value syn‐
300 tax. If no parameters are entered, the current settings are
301 displayed.
302 options:
304 · globalbuffercount: (Optional) Number of global buffers. This
306 option is a legacy option: change the memorysize parameter to
307 alter the number of global buffers. This value cannot be
308 changed once JFR has been initalized. (STRING, default deter‐
309 mined by the value for memorysize)
310 · globalbuffersize: (Optional) Size of the global buffers, in
312 bytes. This option is a legacy option: change the memorysize
313 parameter to alter the size of the global buffers. This value
314 cannot be changed once JFR has been initalized. (STRING, de‐
315 fault determined by the value for memorysize)
316 · maxchunksize: (Optional) Maximum size of an individual data
318 chunk in bytes if one of the following suffixes is not used:
319 'm' or 'M' for megabytes OR 'g' or 'G' for gigabytes. This
320 value cannot be changed once JFR has been initialized.
321 (STRING, 12M)
322 · memorysize: (Optional) Overall memory size, in bytes if one of
324 the following suffixes is not used: 'm' or 'M' for megabytes
325 OR 'g' or 'G' for gigabytes. This value cannot be changed
326 once JFR has been initialized. (STRING, 10M)
327 · repositorypath: (Optional) Path to the location where record‐
329 ings are stored until they are written to a permanent file.
330 (STRING, The default location is the temporary directory for
331 the operating system. On Linux operating systems, the tempo‐
332 rary directory is /tmp. On Windwows, the temporary directory
333 is specified by the TMP environment variable.)
334 · stackdepth: (Optional) Stack depth for stack traces. Setting
336 this value greater than the default of 64 may cause a perfor‐
337 mance degradation. This value cannot be changed once JFR has
338 been initialized. (LONG, 64)
339 · thread_buffer_size: (Optional) Local buffer size for each
341 thread in bytes if one of the following suffixes is not used:
342 'k' or 'K' for kilobytes or 'm' or 'M' for megabytes. Over‐
343 riding this parameter could reduce performance and is not rec‐
344 ommended. This value cannot be changed once JFR has been ini‐
345 tialized. (STRING, 8k)
346 · samplethreads: (Optional) Flag for activating thread sampling.
348 (BOOLEAN, true)
349 JFR.dump [options]
351 Write data to a file while a flight recording is running
352 Impact: Low
354 Note:
356 The options must be specified using either key or key=value syn‐
358 tax. No options are required. The recording continues to run
359 after the data is written.
360 options:
362 · begin: (Optional) Specify the time from which recording data
364 will be included in the dump file. The format is specified as
365 local time. (STRING, no default value)
366 · end: (Optional) Specify the time to which recording data will
368 be included in the dump file. The format is specified as lo‐
369 cal time. (STRING, no default value)
370 Note: For both begin and end, the time must be in a format
372 that can be read by java.time.LocalTime::parse(STRING), ja‐
373 va.time.LocalDateTime::parse(STRING) or java.time.In‐
374 stant::parse(STRING). For example, "13:20:15",
375 "2020-03-17T09:00:00" or "2020-03-17T09:00:00Z".
376 Note: begin and end times correspond to the timestamps found
378 within the recorded information in the flight recording data.
379 Another option is to use a time relative to the current time
381 that is specified by a negative integer followed by "s", "m"
382 or "h". For example, "-12h", "-15m" or "-30s"
383 · filename: (Optional) Name of the file to which the flight
385 recording data is dumped. If no filename is given, a filename
386 is generated from the PID and the current date. The filename
387 may also be a directory in which case, the filename is gener‐
388 ated from the PID and the current date in the specified direc‐
389 tory. (STRING, no default value)
390 · maxage: (Optional) Length of time for dumping the flight
392 recording data to a file. (INTEGER followed by 's' for sec‐
393 onds 'm' for minutes or 'h' for hours, no default value)
394 · maxsize: (Optional) Maximum size for the amount of data to
396 dump from a flight recording in bytes if one of the following
397 suffixes is not used: 'm' or 'M' for megabytes OR 'g' or 'G'
398 for gigabytes. (STRING, no default value)
399 · name: (Optional) Name of the recording. If no name is given,
401 data from all recordings is dumped. (STRING, no default val‐
402 ue)
403 · path-to-gc-root: (Optional) Flag for saving the path to
405 garbage collection (GC) roots at the time the recording data
406 is dumped. The path information is useful for finding memory
407 leaks but collecting it can cause the application to pause for
408 a short period of time. Turn on this flag only when you have
409 an application that you suspect has a memory leak. (BOOLEAN,
410 false)
411 JFR.start [options]
413 Start a flight recording
414 Impact: Low
416 Note:
418 The options must be specified using either key or key=value syn‐
420 tax. If no parameters are entered, then a recording is started
421 with default values.
422 options:
424 · delay: (Optional) Length of time to wait before starting to
426 record (INTEGER followed by 's' for seconds 'm' for minutes or
427 'h' for hours, 0s)
428 · disk: (Optional) Flag for also writing the data to disk while
430 recording (BOOLEAN, true)
431 · dumponexit: (Optional) Flag for writing the recording to disk
433 when the Java Virtual Machine (JVM) shuts down. If set to
434 'true' and no value is given for filename, the recording is
435 written to a file in the directory where the process was
436 started. The file name is a system-generated name that con‐
437 tains the process ID, the recording ID and the current time
438 stamp. (For example: id-1-2019_12_12_10_41.jfr) (BOOLEAN,
439 false)
440 · duration: (Optional) Length of time to record. Note that 0s
442 means forever (INTEGER followed by 's' for seconds 'm' for
443 minutes or 'h' for hours, 0s)
444 · filename: (Optional) Name of the file to which the flight
446 recording data is written when the recording is stopped. If
447 no filename is given, a filename is generated from the PID and
448 the current date and is placed in the directory where the
449 process was started. The filename may also be a directory in
450 which case, the filename is generated from the PID and the
451 current date in the specified directory. (STRING, no default
452 value)
453 · maxage: (Optional) Maximum time to keep the recorded data on
455 disk. This parameter is valid only when the disk parameter is
456 set to true. Note 0s means forever. (INTEGER followed by 's'
457 for seconds 'm' for minutes or 'h' for hours, 0s)
458 · maxsize: (Optional) Maximum size of the data to keep on disk
460 in bytes if one of the following suffixes is not used: 'm' or
461 'M' for megabytes OR 'g' or 'G' for gigabytes. This parameter
462 is valid only when the disk parameter is set to 'true'. The
463 value must not be less than the value for the maxchunksize pa‐
464 rameter set with the JFR.configure command. (STRING, 0 (no
465 maximum size))
466 · name: (Optional) Name of the recording. If no name is provid‐
468 ed, a name is generated. Make note of the generated name that
469 is shown in the response to the command so that you can use it
470 with other commands. (STRING, system-generated default name)
471 · path-to-gc-root: (Optional) Flag for saving the path to
473 garbage collection (GC) roots at the end of a recording. The
474 path information is useful for finding memory leaks but col‐
475 lecting it is time consuming. Turn on this flag only when you
476 have an application that you suspect has a memory leak. If
477 the settings parameter is set to 'profile', then the informa‐
478 tion collected includes the stack trace from where the poten‐
479 tial leaking object was allocated. (BOOLEAN, false)
480 · settings: (Optional) Name of the settings file that identifies
482 which events to record. To specify more than one file, sepa‐
483 rate the names with a comma (','). Include the path if the
484 file is not in JAVA-HOME/lib/jfr. The following profiles are
485 included with the JDK in the JAVA-HOME/lib/jfr directory: 'de‐
486 fault.jfc': collects a predefined set of information with low
487 overhead, so it has minimal impact on performance and can be
488 used with recordings that run continuously; 'profile.jfc':
489 Provides more data than the 'default.jfc' profile, but with
490 more overhead and impact on performance. Use this configura‐
491 tion for short periods of time when more information is need‐
492 ed. Use none to start a recording without a predefined con‐
493 figuration file. (STRING, JAVA-HOME/lib/jfr/default.jfc)
494 JFR.stop [options]
496 Stop a flight recording
497 Impact: Low
499 Note:
501 The options must be specified using either key or key=value syn‐
503 tax. If no parameters are entered, then no recording is
504 stopped.
505 options:
507 · filename: (Optional) Name of the file to which the recording
509 is written when the recording is stopped. If no path is pro‐
510 vided, the data from the recording is discarded. (STRING, no
511 default value)
512 · name: (Optional) Name of the recording (STRING, no default
514 value)
515 JVMTI.agent_load [arguments]
517 Loads JVMTI native agent.
518 Impact: Low
520 Permission: java.lang.management.ManagementPermission(control)
522 arguments:
524 · library path: Absolute path of the JVMTI agent to load.
526 (STRING, no default value)
527 · agent option: (Optional) Option string to pass the agent.
529 (STRING, no default value)
530 JVMTI.data_dump
532 Signals the JVM to do a data-dump request for JVMTI.
533 Impact: High
535 Permission: java.lang.management.ManagementPermission(monitor)
537 ManagementAgent.start [options]
539 Starts remote management agent.
540 Impact: Low --- no impact
542 Note:
544 The following options must be specified using either key or
546 key=value syntax.
547 options:
549 · config.file: (Optional) Sets com.sun.management.config.file
551 (STRING, no default value)
552 · jmxremote.host: (Optional) Sets com.sun.management.jmxre‐
554 mote.host (STRING, no default value)
555 · jmxremote.port: (Optional) Sets com.sun.management.jmxre‐
557 mote.port (STRING, no default value)
558 · jmxremote.rmi.port: (Optional) Sets com.sun.management.jmxre‐
560 mote.rmi.port (STRING, no default value)
561 · jmxremote.ssl: (Optional) Sets com.sun.management.jmxre‐
563 mote.ssl (STRING, no default value)
564 · jmxremote.registry.ssl: (Optional) Sets com.sun.manage‐
566 ment.jmxremote.registry.ssl (STRING, no default value)
567 · jmxremote.authenticate: (Optional) Sets com.sun.manage‐
569 ment.jmxremote.authenticate (STRING, no default value)
570 · jmxremote.password.file: (Optional) Sets com.sun.manage‐
572 ment.jmxremote.password.file (STRING, no default value)
573 · jmxremote.access.file: (Optional) Sets com.sun.manage‐
575 ment.jmxremote.acce ss.file (STRING, no default value)
576 · jmxremote.login.config: (Optional) Sets com.sun.manage‐
578 ment.jmxremote.log in.config (STRING, no default value)
579 · jmxremote.ssl.enabled.cipher.suites: (Optional) Sets
581 com.sun.management.
582 · jmxremote.ssl.enabled.cipher.suite: (STRING, no default value)
584 · jmxremote.ssl.enabled.protocols: (Optional) Sets com.sun.man‐
586 agement.jmxr emote.ssl.enabled.protocols (STRING, no default
587 value)
588 · jmxremote.ssl.need.client.auth: (Optional) Sets com.sun.man‐
590 agement.jmxre mote.need.client.auth (STRING, no default value)
591 · jmxremote.ssl.config.file: (Optional) Sets com.sun.manage‐
593 ment.jmxremote. ssl_config_file (STRING, no default value)
594 · jmxremote.autodiscovery: (Optional) Sets com.sun.manage‐
596 ment.jmxremote.au todiscovery (STRING, no default value)
597 · jdp.port: (Optional) Sets com.sun.management.jdp.port (INT, no
599 default value)
600 · jdp.address: (Optional) Sets com.sun.management.jdp.address
602 (STRING, no default value)
603 · jdp.source_addr: (Optional) Sets com.sun.manage‐
605 ment.jdp.source_addr (STRING, no default value)
606 · jdp.ttl: (Optional) Sets com.sun.management.jdp.ttl (INT, no
608 default value)
609 · jdp.pause: (Optional) Sets com.sun.management.jdp.pause (INT,
611 no default value)
612 · jdp.name: (Optional) Sets com.sun.management.jdp.name (STRING,
614 no default value)
615 ManagementAgent.start_local
617 Starts the local management agent.
618 Impact: Low --- no impact
620 ManagementAgent.status
622 Print the management agent status.
623 Impact: Low --- no impact
625 Permission: java.lang.management.ManagementPermission(monitor)
627 ManagementAgent.stop
629 Stops the remote management agent.
630 Impact: Low --- no impact
632 Thread.print [options]
634 Prints all threads with stacktraces.
635 Impact: Medium --- depends on the number of threads.
637 Permission: java.lang.management.ManagementPermission(monitor)
639 Note:
641 The following options must be specified using either key or
643 key=value syntax.
644 options:
646 · -l: (Optional) Prints java.util.concurrent locks (BOOLEAN,
648 false)
649 VM.classloader_stats
651 Prints statistics about all ClassLoaders.
652 Impact: Low
654 Permission: java.lang.management.ManagementPermission(monitor)
656 VM.class_hierarchy [options] [arguments]
658 Prints a list of all loaded classes, indented to show the class
659 hierarchy. The name of each class is followed by the ClassLoad‐
660 erData* of its ClassLoader, or "null" if it is loaded by the
661 bootstrap class loader.
662 Impact: Medium --- depends on the number of loaded classes.
664 Permission: java.lang.management.ManagementPermission(monitor)
666 Note:
668 The following options must be specified using either key or
670 key=value syntax.
671 options:
673 · -i: (Optional) Inherited interfaces should be printed. (BOOL‐
675 EAN, false)
676 · -s: (Optional) If a class name is specified, it prints the
678 subclasses. If the class name is not specified, only the su‐
679 perclasses are printed. (BOOLEAN, false)
680 arguments:
682 · classname: (Optional) The name of the class whose hierarchy
684 should be printed. If not specified, all class hierarchies
685 are printed. (STRING, no default value)
686 VM.command_line
688 Prints the command line used to start this VM instance.
689 Impact: Low
691 Permission: java.lang.management.ManagementPermission(monitor)
693 VM.dynlibs
695 Prints the loaded dynamic libraries.
696 Impact: Low
698 Permission: java.lang.management.ManagementPermission(monitor)
700 VM.info
702 Prints information about the JVM environment and status.
703 Impact: Low
705 Permission: java.lang.management.ManagementPermission(monitor)
707 VM.log [options]
709 Lists current log configuration, enables/disables/configures a
710 log output, or ro tates all logs.
711 Impact: Low
713 Permission: java.lang.management.ManagementPermission(control)
715 options:
717 Note:
719 The following options must be specified using either key or
721 key=value syntax.
722 · output: (Optional) The name or index (#) of output to config‐
724 ure. (STRING, no default value)
725 · output_options: (Optional) Options for the output. (STRING,
727 no default value)
728 · what: (Optional) Configures what tags to log. (STRING, no de‐
730 fault value )
731 · decorators: (Optional) Configures which decorators to use.
733 Use 'none' or an empty value to remove all. (STRING, no de‐
734 fault value)
735 · disable: (Optional) Turns off all logging and clears the log
737 configuration. (BOOLEAN, no default value)
738 · list: (Optional) Lists current log configuration. (BOOLEAN,
740 no default value)
741 · rotate: (Optional) Rotates all logs. (BOOLEAN, no default
743 value)
744 VM.flags [options]
746 Prints the VM flag options and their current values.
747 Impact: Low
749 Permission: java.lang.management.ManagementPermission(monitor)
751 Note:
753 The following options must be specified using either key or
755 key=value syntax.
756 options:
758 · -all: (Optional) Prints all flags supported by the VM (BOOL‐
760 EAN, false).
761 VM.native_memory [options]
763 Prints native memory usage
764 Impact: Medium
766 Permission: java.lang.management.ManagementPermission(monitor)
768 Note:
770 The following options must be specified using either key or
772 key=value syntax.
773 options:
775 · summary: (Optional) Requests runtime to report current memory
777 summary, which includes total reserved and committed memory,
778 along with memory usage summary by each subsystem. (BOOLEAN,
779 false)
780 · detail: (Optional) Requests runtime to report memory alloca‐
782 tion >= 1K by each callsite. (BOOLEAN, false)
783 · baseline: (Optional) Requests runtime to baseline current mem‐
785 ory usage, so it can be compared against in later time.
786 (BOOLEAN, false)
787 · summary.diff: (Optional) Requests runtime to report memory
789 summary comparison against previous baseline. (BOOLEAN,
790 false)
791 · detail.diff: (Optional) Requests runtime to report memory de‐
793 tail comparison against previous baseline, which shows the
794 memory allocation activities at different callsites. (BOOL‐
795 EAN, false)
796 · shutdown: (Optional) Requests runtime to shutdown itself and
798 free the memory used by runtime. (BOOLEAN, false)
799 · statistics: (Optional) Prints tracker statistics for tuning
801 purpose. (BOOLEAN, false)
802 · scale: (Optional) Memory usage in which scale, KB, MB or GB
804 (STRING, KB)
805 VM.print_touched_methods
807 Prints all methods that have ever been touched during the life‐
808 time of this JVM.
809 Impact: Medium --- depends on Java content.
811 VM.set_flag [arguments]
813 Sets the VM flag option by using the provided value.
814 Impact: Low
816 Permission: java.lang.management.ManagementPermission(control)
818 arguments:
820 · flag name: The name of the flag that you want to set (STRING,
822 no default value)
823 · string value: (Optional) The value that you want to set
825 (STRING, no default value)
826 VM.stringtable [options]
828 Dumps the string table.
829 Impact: Medium --- depends on the Java content.
831 Permission: java.lang.management.ManagementPermission(monitor)
833 Note:
835 The following options must be specified using either key or
837 key=value syntax.
838 options:
840 · -verbose: (Optional) Dumps the content of each string in the
842 table (BOOLEAN, false)
843 VM.symboltable [options]
845 Dumps the symbol table.
846 Impact: Medium --- depends on the Java content.
848 Permission: java.lang.management.ManagementPermission(monitor)
850 Note:
852 The following options must be specified using either key or
854 key=value syntax).
855 options:
857 · -verbose: (Optional) Dumps the content of each symbol in the
859 table (BOOLEAN, false)
860 VM.systemdictionary
862 Prints the statistics for dictionary hashtable sizes and bucket
863 length.
864 Impact: Medium
866 Permission: java.lang.management.ManagementPermission(monitor)
868 Note:
870 The following options must be specified using either key or
872 key=value syntax.
873 options:
875 · verbose: (Optional) Dump the content of each dictionary entry
877 for all class loaders (BOOLEAN, false) .
878 VM.system_properties
880 Prints the system properties.
881 Impact: Low
883 Permission: java.util.PropertyPermission(*, read)
885 VM.uptime [options]
887 Prints the VM uptime.
888 Impact: Low
890 Note:
892 The following options must be specified using either key or
894 key=value syntax.
895 options:
897 · -date: (Optional) Adds a prefix with the current date (BOOL‐
899 EAN, false)
900 VM.version
902 Prints JVM version information.
903 Impact: Low
905 Permission: java.util.PropertyPermission(java.vm.version, read)
907JDK 14 2020 JCMD(1)