title: jcmd : where can I find complementary information
body: <p><strong>jcmd</strong> is a promising tool regrouping utilities of jmap, jsp, etc...<br>
  You can find <a href="https://docs.oracle.com/javase/8/docs/technotes/guides/troubleshoot/tooldescr006.html" rel="noreferrer">introduction</a> and <a href="https://docs.oracle.com/javase/8/docs/technotes/tools/windows/jcmd.html" rel="noreferrer">man page</a> but still it's very light.</p>
  
  <p>On the web, I found apparently existing commands like <strong>GC.heap_info</strong>, that I've never been able to use for my tests.</p>
  
  <p>Some of these commands need special flags. <code>-XX:NativeMemoryTracking=detail</code> will give you <code>VM.native_memory</code> command, for instance.</p>
  
  <p>But for some others it's not clear how to <em>activate</em> them or if it depends of the jdk version, etc..<br>
  I can't even find an exhaustive list of existing command.</p>
  
  <p>Any info?</p>
  
  <hr>
  
  <p><em>Edit</em>
  Thx to <a href="https://stackoverflow.com/a/41893371/2072419">@apangin response</a>, I've started to compute a short summary of available commands by jvm version.</p>
  
  <p>Disclaimer : it comes from code teardown only, not real test</p>
  
  <h2>jdk8</h2>
  
  <ul>
  <li>help</li>
  <li>VM.uptime [options]</li>
  <li>VM.flags [options]</li>
  <li>VM.system_properties</li>
  <li>VM.command_line</li>
  <li>VM.version</li>
  <li>VM.native_memory [options]</li>
  <li>VM.check_commercial_features</li>
  <li>VM.unlock_commercial_features</li>
  <li>Thread.print [options]</li>
  <li>GC.run</li>
  <li>GC.run_finalization</li>
  <li>GC.rotate_log</li>
  <li>GC.class_stats [options]</li>
  <li>GC.class_histogram [options]</li>
  <li>GC.heap_dump [options]</li>
  <li>ManagementAgent.start_local</li>
  <li>ManagementAgent.start [options]</li>
  <li>ManagementAgent.stopJFR.start [options]</li>
  <li>JFR.stop [options]</li>
  <li>JFR.dump [options]</li>
  <li>JFR.check [options]</li>
  </ul>
  
  <h2>jdk9</h2>
  
  <p><strong>only the additional</strong></p>
  
  <ul>
  <li>VM.set_flag [options]</li>
  <li>VM.info</li>
  <li>VM.class_hierarchy [options]</li>
  <li>VM.dynlibs</li>
  <li>VM.print_touched_methods</li>
  <li>JVMTI.data_dump</li>
  <li>JVMTI.agent_load [options]</li>
  <li>GC.finalizer_info</li>
  <li>GC.heap_info</li>
  <li>ManagementAgent.status</li>
  <li>ManagementAgent.stop</li>
  <li>Compiler.queue</li>
  <li>Compiler.codelist</li>
  <li>Compiler.codecache</li>
  <li>Compiler.directives_print</li>
  <li>Compiler.directives_remove</li>
  <li>Compiler.directives_add [options]</li>
  <li>Compiler.directives_clear</li>
  </ul>