Java Tools Tutorials - Herong's Tutorial Examples - v6.23, by Herong Yang
"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
javac - The Java Program Compiler
java - The Java Program Launcher
jpackage - Binary Package Builder
javadoc - The Java Document Generator
jdeps - The Java Class Dependency Analyzer
jdeprscan - The Java Deprecated API Scanner
►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
jhsdb - The Java HotSpot Debugger
jvisualvm (Java VisualVM) - JVM Visual Tool
javap - The Java Class File Disassembler
keytool - Public Key Certificate Tool
jrunscript - Script Code Shell
native2ascii - Native-to-ASCII Encoding Converter