jcmd(1) Troubleshooting Tools jcmd(1)
NAME
jcmd - Sends diagnostic command requests to a running Java Virtual Machine (JVM).
SYNOPSIS
jcmd [-l|-h|-help]
jcmd pid|main-class PerfCounter.print
jcmd pid|main-class -f filename
jcmd pid|main-class command[ arguments]
DESCRIPTION
The jcmd utility is used to send diagnostic command requests to the JVM. It must be used
on the same machine on which the JVM is running, and have the same effective user and
group identifiers that were used to launch the JVM.
Note
+----------------------------------------------------------------------------------------------------------------------------+
| |
| To invoke diagnostic commands from a |
| remote machine or with different |
| identifiers, you can use the |
| com.sun.management.DiagnosticCommandMBean |
| interface. For more information about |
| the DiagnosticCommandMBean interface, |
| see the API documentation at |
| http://docs.oracle.com/javase/8/docs/jre/api/management/extension/com/sun/management/DiagnosticCommandMBean.html |
+----------------------------------------------------------------------------------------------------------------------------+
If you run jcmd without arguments or with the -l option, it prints the list of running
Java process identifiers with the main class and command-line arguments that were used to
launch the process. Running jcmd with the -h or -help option prints the tool's help
message.
If you specify the processes identifier (pid) or the main class (main-class) as the first
argument, jcmd sends the diagnostic command request to the Java process with the specified
identifier or to all Java processes with the specified name of the main class. You can
also send the diagnostic command request to all available Java processes by specifying 0
as the process identifier. Use one of the following as the diagnostic command request:
Perfcounter.print
Prints the performance counters available for the specified Java process. The list of
performance counters might vary with the Java process.
-f filename
The name of the file from which to read diagnostic commands and send them to the
specified Java process. Used only with the -f option. Each command in the file must be
written on a single line. Lines starting with a number sign (#) are ignored.
Processing of the file ends when all lines have been read or when a line containing
the stop keyword is read.
command [arguments]
The command to be sent to the specified Java process. The list of available diagnostic
commands for a given process can be obtained by sending the help command to this
process. Each diagnostic command has its own set of arguments. To see the description,
syntax, and a list of available arguments for a command, use the name of the command
as the argument for the help command.
Note: If any arguments contain spaces, you must surround them with single or double
quotation marks (' or "). In addition, you must escape single or double quotation
marks with a backslash (\) to prevent the operating system shell from processing
quotation marks. Alternatively, you can surround these arguments with single quotation
marks and then with double quotation marks (or with double quotation marks and then
with single quotation marks).
OPTIONS
Options are mutually exclusive.
-f filename
Reads commands from the specified file. This option can be used only if you specify
the process identifier or the main class as the first argument. Each command in the
file must be written on a single line. Lines starting with a number sign (#) are
ignored. Processing of the file ends when all lines have been read or when a line
containing the stop keyword is read.
-h
-help
Prints a help message.
-l
Prints the list of running Java processes identifiers with the main class and
command-line arguments.
SEE ALSO
o jps(1)
JDK 8 03 March 2015 jcmd(1)
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