1JCMD(1) JDK Commands JCMD(1)
2
3
4
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
12 jcmd [-l]
13
14 jcmd -h
15
16 pid When used, the jcmd utility sends the diagnostic command request
17 to the process ID for the Java process.
18
19 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
23 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
35 Perfcounter.print
36 Prints the performance counters exposed by the specified Java
37 process.
38
39 -f filename
40 Reads and executes commands from a specified file, filename.
41
42 -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
48 Note:
49
50 Using jcmd without arguments is the same as using jcmd -l.
51
52 -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
63 jcmd pid help command
64
65 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
73 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
91 The following commands are available:
92
93 help [options] [arguments]
94 For more information about a specific command.
95
96 arguments:
97
98 · command name: The name of the command for which we want help
99 (STRING, no default value)
100
101 Note:
102
103 The following options must be specified using either key or
104 key=value syntax.
105
106 options:
107
108 · -all: (Optional) Show help for all commands (BOOLEAN, false) .
109
110 Compiler.codecache
111 Prints code cache layout and bounds.
112
113 Impact: Low
114
115 Permission: java.lang.management.ManagementPermission(monitor)
116
117 Compiler.codelist
118 Prints all compiled methods in code cache that are alive.
119
120 Impact: Medium
121
122 Permission: java.lang.management.ManagementPermission(monitor)
123
124 Compiler.queue
125 Prints methods queued for compilation.
126
127 Impact: Low
128
129 Permission: java.lang.management.ManagementPermission(monitor)
130
131 Compiler.directives_add *filename* *arguments*
132 Adds compiler directives from a file.
133
134 Impact: Low
135
136 Permission: java.lang.management.ManagementPermission(monitor)
137
138 arguments:
139
140 filename: The name of the directives file (STRING, no default
141 value)
142
143 Compiler.directives_clear
144 Remove all compiler directives.
145
146 Impact: Low
147
148 Permission: java.lang.management.ManagementPermission(monitor)
149
150 Compiler.directives_print
151 Prints all active compiler directives.
152
153 Impact: Low
154
155 Permission: java.lang.management.ManagementPermission(monitor)
156
157 Compiler.directives_remove
158 Remove latest added compiler directive.
159
160 Impact: Low
161
162 Permission: java.lang.management.ManagementPermission(monitor)
163
164 GC.class_histogram [options]
165 Provides statistics about the Java heap usage.
166
167 Impact: High --- depends on Java heap size and content.
168
169 Permission: java.lang.management.ManagementPermission(monitor)
170
171 Note:
172
173 The options must be specified using either key or key=value syn‐
174 tax.
175
176 options:
177
178 · -all: (Optional) Inspects all objects, including unreachable
179 objects (BOOLEAN, false)
180
181 GC.finalizer_info
182 Provides information about the Java finalization queue.
183
184 Impact: Medium
185
186 Permission: java.lang.management.ManagementPermission(monitor)
187
188 GC.heap_dump [options] [arguments]
189 Generates a HPROF format dump of the Java heap.
190
191 Impact: High --- depends on the Java heap size and content. Re‐
192 quest a full GC unless the -all option is specified.
193
194 Permission: java.lang.management.ManagementPermission(monitor)
195
196 Note:
197
198 The following options must be specified using either key or
199 key=value syntax.
200
201 options:
202
203 · -all: (Optional) Dump all objects, including unreachable ob‐
204 jects (BOOLEAN, false)
205
206 arguments:
207
208 · filename: The name of the dump file (STRING, no default value)
209
210 GC.heap_info
211 Provides generic Java heap information.
212
213 Impact: Medium
214
215 Permission: java.lang.management.ManagementPermission(monitor)
216
217 GC.run Calls java.lang.System.gc().
218
219 Impact: Medium --- depends on the Java heap size and content.
220
221 GC.run_finalization
222 Calls java.lang.System.runFinalization().
223
224 Impact: Medium --- depends on the Java content.
225
226 JFR.check [options]
227 Show information about a running flight recording
228
229 Impact: Low
230
231 Note:
232
233 The options must be specified using either key or key=value syn‐
234 tax. If no parameters are entered, information for all active
235 recordings is shown.
236
237 options:
238
239 · name: (Optional) Name of the flight recording. (STRING, no
240 default value)
241
242 · verbose: (Optional) Flag for printing the event settings for
243 the recording (BOOLEAN, false)
244
245 JFR.configure [options]
246 Set the parameters for a flight recording
247
248 Impact: Low
249
250 Note:
251
252 The options must be specified using either key or key=value syn‐
253 tax. If no parameters are entered, the current settings are
254 displayed.
255
256 options:
257
258 · globalbuffercount: (Optional) Number of global buffers. This
259 option is a legacy option: change the memorysize parameter to
260 alter the number of global buffers. This value cannot be
261 changed once JFR has been initalized. (STRING, default deter‐
262 mined by the value for memorysize)
263
264 · globalbuffersize: (Optional) Size of the global buffers, in
265 bytes. This option is a legacy option: change the memorysize
266 parameter to alter the size of the global buffers. This value
267 cannot be changed once JFR has been initalized. (STRING, de‐
268 fault determined by the value for memorysize)
269
270 · maxchunksize: (Optional) Maximum size of an individual data
271 chunk in bytes if one of the following suffixes is not used:
272 'm' or 'M' for megabytes OR 'g' or 'G' for gigabytes. This
273 value cannot be changed once JFR has been initialized.
274 (STRING, 12M)
275
276 · memorysize: (Optional) Overall memory size, in bytes if one of
277 the following suffixes is not used: 'm' or 'M' for megabytes
278 OR 'g' or 'G' for gigabytes. This value cannot be changed
279 once JFR has been initialized. (STRING, 10M)
280
281 · repositorypath: (Optional) Path to the location where record‐
282 ings are stored until they are written to a permanent file.
283 (STRING, The default location is the temporary directory for
284 the operating system. On Linux operating systems, the tempo‐
285 rary directory is /tmp. On Windwows, the temporary directory
286 is specified by the TMP environment variable.)
287
288 · stackdepth: (Optional) Stack depth for stack traces. Setting
289 this value greater than the default of 64 may cause a perfor‐
290 mance degradation. This value cannot be changed once JFR has
291 been initialized. (LONG, 64)
292
293 · thread_buffer_size: (Optional) Local buffer size for each
294 thread in bytes if one of the following suffixes is not used:
295 'k' or 'K' for kilobytes or 'm' or 'M' for megabytes. Over‐
296 riding this parameter could reduce performance and is not rec‐
297 ommended. This value cannot be changed once JFR has been ini‐
298 tialized. (STRING, 8k)
299
300 · samplethreads: (Optional) Flag for activating thread sampling.
301 (BOOLEAN, true)
302
303 JFR.dump [options]
304 Write data to a file while a flight recording is running
305
306 Impact: Low
307
308 Note:
309
310 The options must be specified using either key or key=value syn‐
311 tax. No options are required. The recording continues to run
312 after the data is written.
313
314 options:
315
316 · begin: (Optional) Specify the time from which recording data
317 will be included in the dump file. The format is specified as
318 local time. (STRING, no default value)
319
320 · end: (Optional) Specify the time to which recording data will
321 be included in the dump file. The format is specified as lo‐
322 cal time. (STRING, no default value)
323
324 Note: For both begin and end, the time must be in a format
325 that can be read by java.time.LocalTime::parse(STRING), ja‐
326 va.time.LocalDateTime::parse(STRING) or java.time.In‐
327 stant::parse(STRING). For example, "13:20:15",
328 "2020-03-17T09:00:00" or "2020-03-17T09:00:00Z".
329
330 Note: begin and end times correspond to the timestamps found
331 within the recorded information in the flight recording data.
332
333 Another option is to use a time relative to the current time
334 that is specified by a negative integer followed by "s", "m"
335 or "h". For example, "-12h", "-15m" or "-30s"
336
337 · filename: (Optional) Name of the file to which the flight
338 recording data is dumped. If no filename is given, a filename
339 is generated from the PID and the current date. The filename
340 may also be a directory in which case, the filename is gener‐
341 ated from the PID and the current date in the specified direc‐
342 tory. (STRING, no default value)
343
344 · maxage: (Optional) Length of time for dumping the flight
345 recording data to a file. (INTEGER followed by 's' for sec‐
346 onds 'm' for minutes or 'h' for hours, no default value)
347
348 · maxsize: (Optional) Maximum size for the amount of data to
349 dump from a flight recording in bytes if one of the following
350 suffixes is not used: 'm' or 'M' for megabytes OR 'g' or 'G'
351 for gigabytes. (STRING, no default value)
352
353 · name: (Optional) Name of the recording. If no name is given,
354 data from all recordings is dumped. (STRING, no default val‐
355 ue)
356
357 · path-to-gc-root: (Optional) Flag for saving the path to
358 garbage collection (GC) roots at the time the recording data
359 is dumped. The path information is useful for finding memory
360 leaks but collecting it can cause the application to pause for
361 a short period of time. Turn on this flag only when you have
362 an application that you suspect has a memory leak. (BOOLEAN,
363 false)
364
365 JFR.start [options]
366 Start a flight recording
367
368 Impact: Low
369
370 Note:
371
372 The options must be specified using either key or key=value syn‐
373 tax. If no parameters are entered, then a recording is started
374 with default values.
375
376 options:
377
378 · delay: (Optional) Length of time to wait before starting to
379 record (INTEGER followed by 's' for seconds 'm' for minutes or
380 'h' for hours, 0s)
381
382 · disk: (Optional) Flag for also writing the data to disk while
383 recording (BOOLEAN, true)
384
385 · dumponexit: (Optional) Flag for writing the recording to disk
386 when the Java Virtual Machine (JVM) shuts down. If set to
387 'true' and no value is given for filename, the recording is
388 written to a file in the directory where the process was
389 started. The file name is a system-generated name that con‐
390 tains the process ID, the recording ID and the current time
391 stamp. (For example: id-1-2019_12_12_10_41.jfr) (BOOLEAN,
392 false)
393
394 · duration: (Optional) Length of time to record. Note that 0s
395 means forever (INTEGER followed by 's' for seconds 'm' for
396 minutes or 'h' for hours, 0s)
397
398 · filename: (Optional) Name of the file to which the flight
399 recording data is written when the recording is stopped. If
400 no filename is given, a filename is generated from the PID and
401 the current date and is placed in the directory where the
402 process was started. The filename may also be a directory in
403 which case, the filename is generated from the PID and the
404 current date in the specified directory. (STRING, no default
405 value)
406
407 · maxage: (Optional) Maximum time to keep the recorded data on
408 disk. This parameter is valid only when the disk parameter is
409 set to true. Note 0s means forever. (INTEGER followed by 's'
410 for seconds 'm' for minutes or 'h' for hours, 0s)
411
412 · maxsize: (Optional) Maximum size of the data to keep on disk
413 in bytes if one of the following suffixes is not used: 'm' or
414 'M' for megabytes OR 'g' or 'G' for gigabytes. This parameter
415 is valid only when the disk parameter is set to 'true'. The
416 value must not be less than the value for the maxchunksize pa‐
417 rameter set with the JFR.configure command. (STRING, 0 (no
418 maximum size))
419
420 · name: (Optional) Name of the recording. If no name is provid‐
421 ed, a name is generated. Make note of the generated name that
422 is shown in the response to the command so that you can use it
423 with other commands. (STRING, system-generated default name)
424
425 · path-to-gc-root: (Optional) Flag for saving the path to
426 garbage collection (GC) roots at the end of a recording. The
427 path information is useful for finding memory leaks but col‐
428 lecting it is time consuming. Turn on this flag only when you
429 have an application that you suspect has a memory leak. If
430 the settings parameter is set to 'profile', then the informa‐
431 tion collected includes the stack trace from where the poten‐
432 tial leaking object was allocated. (BOOLEAN, false)
433
434 · settings: (Optional) Name of the settings file that identifies
435 which events to record. To specify more than one file, sepa‐
436 rate the names with a comma (','). Include the path if the
437 file is not in JAVA-HOME/lib/jfr. The following profiles are
438 included with the JDK in the JAVA-HOME/lib/jfr directory: 'de‐
439 fault.jfc': collects a predefined set of information with low
440 overhead, so it has minimal impact on performance and can be
441 used with recordings that run continuously; 'profile.jfc':
442 Provides more data than the 'default.jfc' profile, but with
443 more overhead and impact on performance. Use this configura‐
444 tion for short periods of time when more information is need‐
445 ed. Use none to start a recording without a predefined con‐
446 figuration file. (STRING, JAVA-HOME/lib/jfr/default.jfc)
447
448 JFR.stop [options]
449 Stop a flight recording
450
451 Impact: Low
452
453 Note:
454
455 The options must be specified using either key or key=value syn‐
456 tax. If no parameters are entered, then no recording is
457 stopped.
458
459 options:
460
461 · filename: (Optional) Name of the file to which the recording
462 is written when the recording is stopped. If no path is pro‐
463 vided, the data from the recording is discarded. (STRING, no
464 default value)
465
466 · name: (Optional) Name of the recording (STRING, no default
467 value)
468
469 JVMTI.agent_load [arguments]
470 Loads JVMTI native agent.
471
472 Impact: Low
473
474 Permission: java.lang.management.ManagementPermission(control)
475
476 arguments:
477
478 · library path: Absolute path of the JVMTI agent to load.
479 (STRING, no default value)
480
481 · agent option: (Optional) Option string to pass the agent.
482 (STRING, no default value)
483
484 JVMTI.data_dump
485 Signals the JVM to do a data-dump request for JVMTI.
486
487 Impact: High
488
489 Permission: java.lang.management.ManagementPermission(monitor)
490
491 ManagementAgent.start [options]
492 Starts remote management agent.
493
494 Impact: Low --- no impact
495
496 Note:
497
498 The following options must be specified using either key or
499 key=value syntax.
500
501 options:
502
503 · config.file: (Optional) Sets com.sun.management.config.file
504 (STRING, no default value)
505
506 · jmxremote.host: (Optional) Sets com.sun.management.jmxre‐
507 mote.host (STRING, no default value)
508
509 · jmxremote.port: (Optional) Sets com.sun.management.jmxre‐
510 mote.port (STRING, no default value)
511
512 · jmxremote.rmi.port: (Optional) Sets com.sun.management.jmxre‐
513 mote.rmi.port (STRING, no default value)
514
515 · jmxremote.ssl: (Optional) Sets com.sun.management.jmxre‐
516 mote.ssl (STRING, no default value)
517
518 · jmxremote.registry.ssl: (Optional) Sets com.sun.manage‐
519 ment.jmxremote.registry.ssl (STRING, no default value)
520
521 · jmxremote.authenticate: (Optional) Sets com.sun.manage‐
522 ment.jmxremote.authenticate (STRING, no default value)
523
524 · jmxremote.password.file: (Optional) Sets com.sun.manage‐
525 ment.jmxremote.password.file (STRING, no default value)
526
527 · jmxremote.access.file: (Optional) Sets com.sun.manage‐
528 ment.jmxremote.acce ss.file (STRING, no default value)
529
530 · jmxremote.login.config: (Optional) Sets com.sun.manage‐
531 ment.jmxremote.log in.config (STRING, no default value)
532
533 · jmxremote.ssl.enabled.cipher.suites: (Optional) Sets
534 com.sun.management.
535
536 · jmxremote.ssl.enabled.cipher.suite: (STRING, no default value)
537
538 · jmxremote.ssl.enabled.protocols: (Optional) Sets com.sun.man‐
539 agement.jmxr emote.ssl.enabled.protocols (STRING, no default
540 value)
541
542 · jmxremote.ssl.need.client.auth: (Optional) Sets com.sun.man‐
543 agement.jmxre mote.need.client.auth (STRING, no default value)
544
545 · jmxremote.ssl.config.file: (Optional) Sets com.sun.manage‐
546 ment.jmxremote. ssl_config_file (STRING, no default value)
547
548 · jmxremote.autodiscovery: (Optional) Sets com.sun.manage‐
549 ment.jmxremote.au todiscovery (STRING, no default value)
550
551 · jdp.port: (Optional) Sets com.sun.management.jdp.port (INT, no
552 default value)
553
554 · jdp.address: (Optional) Sets com.sun.management.jdp.address
555 (STRING, no default value)
556
557 · jdp.source_addr: (Optional) Sets com.sun.manage‐
558 ment.jdp.source_addr (STRING, no default value)
559
560 · jdp.ttl: (Optional) Sets com.sun.management.jdp.ttl (INT, no
561 default value)
562
563 · jdp.pause: (Optional) Sets com.sun.management.jdp.pause (INT,
564 no default value)
565
566 · jdp.name: (Optional) Sets com.sun.management.jdp.name (STRING,
567 no default value)
568
569 ManagementAgent.start_local
570 Starts the local management agent.
571
572 Impact: Low --- no impact
573
574 ManagementAgent.status
575 Print the management agent status.
576
577 Impact: Low --- no impact
578
579 Permission: java.lang.management.ManagementPermission(monitor)
580
581 ManagementAgent.stop
582 Stops the remote management agent.
583
584 Impact: Low --- no impact
585
586 Thread.print [options]
587 Prints all threads with stacktraces.
588
589 Impact: Medium --- depends on the number of threads.
590
591 Permission: java.lang.management.ManagementPermission(monitor)
592
593 Note:
594
595 The following options must be specified using either key or
596 key=value syntax.
597
598 options:
599
600 · -l: (Optional) Prints java.util.concurrent locks (BOOLEAN,
601 false)
602
603 VM.classloader_stats
604 Prints statistics about all ClassLoaders.
605
606 Impact: Low
607
608 Permission: java.lang.management.ManagementPermission(monitor)
609
610 VM.class_hierarchy [options] [arguments]
611 Prints a list of all loaded classes, indented to show the class
612 hierarchy. The name of each class is followed by the ClassLoad‐
613 erData* of its ClassLoader, or "null" if it is loaded by the
614 bootstrap class loader.
615
616 Impact: Medium --- depends on the number of loaded classes.
617
618 Permission: java.lang.management.ManagementPermission(monitor)
619
620 Note:
621
622 The following options must be specified using either key or
623 key=value syntax.
624
625 options:
626
627 · -i: (Optional) Inherited interfaces should be printed. (BOOL‐
628 EAN, false)
629
630 · -s: (Optional) If a class name is specified, it prints the
631 subclasses. If the class name is not specified, only the su‐
632 perclasses are printed. (BOOLEAN, false)
633
634 arguments:
635
636 · classname: (Optional) The name of the class whose hierarchy
637 should be printed. If not specified, all class hierarchies
638 are printed. (STRING, no default value)
639
640 VM.command_line
641 Prints the command line used to start this VM instance.
642
643 Impact: Low
644
645 Permission: java.lang.management.ManagementPermission(monitor)
646
647 VM.dynlibs
648 Prints the loaded dynamic libraries.
649
650 Impact: Low
651
652 Permission: java.lang.management.ManagementPermission(monitor)
653
654 VM.info
655 Prints information about the JVM environment and status.
656
657 Impact: Low
658
659 Permission: java.lang.management.ManagementPermission(monitor)
660
661 VM.log [options]
662 Lists current log configuration, enables/disables/configures a
663 log output, or rotates all logs.
664
665 Impact: Low
666
667 Permission: java.lang.management.ManagementPermission(control)
668
669 options:
670
671 Note:
672
673 The following options must be specified using either key or
674 key=value syntax.
675
676 · output: (Optional) The name or index (#) of output to config‐
677 ure. (STRING, no default value)
678
679 · output_options: (Optional) Options for the output. (STRING,
680 no default value)
681
682 · what: (Optional) Configures what tags to log. (STRING, no de‐
683 fault value )
684
685 · decorators: (Optional) Configures which decorators to use.
686 Use 'none' or an empty value to remove all. (STRING, no de‐
687 fault value)
688
689 · disable: (Optional) Turns off all logging and clears the log
690 configuration. (BOOLEAN, no default value)
691
692 · list: (Optional) Lists current log configuration. (BOOLEAN,
693 no default value)
694
695 · rotate: (Optional) Rotates all logs. (BOOLEAN, no default
696 value)
697
698 VM.flags [options]
699 Prints the VM flag options and their current values.
700
701 Impact: Low
702
703 Permission: java.lang.management.ManagementPermission(monitor)
704
705 Note:
706
707 The following options must be specified using either key or
708 key=value syntax.
709
710 options:
711
712 · -all: (Optional) Prints all flags supported by the VM (BOOL‐
713 EAN, false).
714
715 VM.native_memory [options]
716 Prints native memory usage
717
718 Impact: Medium
719
720 Permission: java.lang.management.ManagementPermission(monitor)
721
722 Note:
723
724 The following options must be specified using either key or
725 key=value syntax.
726
727 options:
728
729 · summary: (Optional) Requests runtime to report current memory
730 summary, which includes total reserved and committed memory,
731 along with memory usage summary by each subsystem. (BOOLEAN,
732 false)
733
734 · detail: (Optional) Requests runtime to report memory alloca‐
735 tion >= 1K by each callsite. (BOOLEAN, false)
736
737 · baseline: (Optional) Requests runtime to baseline current mem‐
738 ory usage, so it can be compared against in later time.
739 (BOOLEAN, false)
740
741 · summary.diff: (Optional) Requests runtime to report memory
742 summary comparison against previous baseline. (BOOLEAN,
743 false)
744
745 · detail.diff: (Optional) Requests runtime to report memory de‐
746 tail comparison against previous baseline, which shows the
747 memory allocation activities at different callsites. (BOOL‐
748 EAN, false)
749
750 · shutdown: (Optional) Requests runtime to shutdown itself and
751 free the memory used by runtime. (BOOLEAN, false)
752
753 · statistics: (Optional) Prints tracker statistics for tuning
754 purpose. (BOOLEAN, false)
755
756 · scale: (Optional) Memory usage in which scale, KB, MB or GB
757 (STRING, KB)
758
759 VM.print_touched_methods
760 Prints all methods that have ever been touched during the life‐
761 time of this JVM.
762
763 Impact: Medium --- depends on Java content.
764
765 VM.set_flag [arguments]
766 Sets the VM flag option by using the provided value.
767
768 Impact: Low
769
770 Permission: java.lang.management.ManagementPermission(control)
771
772 arguments:
773
774 · flag name: The name of the flag that you want to set (STRING,
775 no default value)
776
777 · string value: (Optional) The value that you want to set
778 (STRING, no default value)
779
780 VM.stringtable [options]
781 Dumps the string table.
782
783 Impact: Medium --- depends on the Java content.
784
785 Permission: java.lang.management.ManagementPermission(monitor)
786
787 Note:
788
789 The following options must be specified using either key or
790 key=value syntax.
791
792 options:
793
794 · -verbose: (Optional) Dumps the content of each string in the
795 table (BOOLEAN, false)
796
797 VM.symboltable [options]
798 Dumps the symbol table.
799
800 Impact: Medium --- depends on the Java content.
801
802 Permission: java.lang.management.ManagementPermission(monitor)
803
804 Note:
805
806 The following options must be specified using either key or
807 key=value syntax).
808
809 options:
810
811 · -verbose: (Optional) Dumps the content of each symbol in the
812 table (BOOLEAN, false)
813
814 VM.systemdictionary
815 Prints the statistics for dictionary hashtable sizes and bucket
816 length.
817
818 Impact: Medium
819
820 Permission: java.lang.management.ManagementPermission(monitor)
821
822 Note:
823
824 The following options must be specified using either key or
825 key=value syntax.
826
827 options:
828
829 · verbose: (Optional) Dump the content of each dictionary entry
830 for all class loaders (BOOLEAN, false) .
831
832 VM.system_properties
833 Prints the system properties.
834
835 Impact: Low
836
837 Permission: java.util.PropertyPermission(*, read)
838
839 VM.uptime [options]
840 Prints the VM uptime.
841
842 Impact: Low
843
844 Note:
845
846 The following options must be specified using either key or
847 key=value syntax.
848
849 options:
850
851 · -date: (Optional) Adds a prefix with the current date (BOOL‐
852 EAN, false)
853
854 VM.version
855 Prints JVM version information.
856
857 Impact: Low
858
859 Permission: java.util.PropertyPermission(java.vm.version, read)
860
861
862
863JDK 16 2021 JCMD(1)