"jcmd 0 help" - Listing JVM Diagnostic Commands

This section provides a tutorial example on how to use 'jcmd 0 help' command to get a list of diagnostic commands that are supported in each running JVM.

If you want to know which diagnostic command can be fired to a specific JVM, you can run the "jcmd <pid> help" command to get a list of valid commands for the given JVM.

Or you can run the "jcmd 0 help" command to a list of valid command for each every JVM on the local machine. For example, if I have 2 JVMs running: "java LongSleep" and "jshell", I will get the following output from "jcmd 0 help":

herong> jcmd 0 help

10848:
The following commands are available:
JFR.configure
JFR.stop
JFR.start
JFR.dump
JFR.check
VM.log
VM.native_memory
VM.check_commercial_features
VM.unlock_commercial_features
ManagementAgent.status
ManagementAgent.stop
ManagementAgent.start_local
ManagementAgent.start
Compiler.directives_clear
Compiler.directives_remove
Compiler.directives_add
Compiler.directives_print
VM.print_touched_methods
Compiler.codecache
Compiler.codelist
Compiler.queue
VM.classloader_stats
Thread.print
JVMTI.data_dump
JVMTI.agent_load
VM.stringtable
VM.symboltable
VM.class_hierarchy
VM.systemdictionary
GC.class_stats
GC.class_histogram
GC.heap_dump
GC.finalizer_info
GC.heap_info
GC.run_finalization
GC.run
VM.info
VM.uptime
VM.dynlibs
VM.set_flag
VM.flags
VM.system_properties
VM.command_line
VM.version
help

For more information about a specific command use 'help <command>'.

6024:
The following commands are available:
JFR.configure
JFR.stop
JFR.start
JFR.dump
JFR.check
VM.log
...

Wow! It looks like we can:

Table of Contents

 About This Book

 Java Tools Terminology

 Java Tools Included in JDK

 javac - The Java Program Compiler

 jar - The JAR File Tool

 jlink - The JRE Linker

 jmod - The JMOD File Tool

 jimage - The JIMAGE File Tool

 jpackage - Binary Package Builder

 java - The Java Program Launcher

 jdeps - The Java Class Dependency Analyzer

 jdeprscan - The Java Deprecated API Scanner

 jdb - The Java Debugger

jcmd - The JVM Diagnostic Tool

 jcmd - JVM Diagnostic Tool Command

"jcmd 0 help" - Listing JVM Diagnostic Commands

 "jcmd 0 VM.*" - Running VM Diagnostic Commands

 "jcmd 0 GC.*" - Running GC Diagnostic Commands

 "jcmd 0 Thread.print" - Generating Thread Dump

 jconsole - Java Monitoring and Management Console

 jstat - JVM Statistics Monitoring Tool

 JVM Troubleshooting Tools

 jhsdb - The Java HotSpot Debugger

 jvisualvm (Java VisualVM) - JVM Visual Tool

 jmc - Java Mission Control

 javap - The Java Class File Disassembler

 keytool - Public Key Certificate Tool

 jarsigner - JAR File Signer

 jshell - Java Language Shell

 jrunscript - Script Code Shell

 serialver - serialVersionUID Generator

 native2ascii - Native-to-ASCII Encoding Converter

 Outdated Tutorials

 References

 Full Version in PDF/EPUB