jps(1) jps(1)
NAME
jps - Java Virtual Machine Process Status Tool
SYNOPSIS
jps [options] [hostid]
DESCRIPTION
The jps tool lists the instrumented HotSpot Java Virtual Machines (JVMs) on the target system. The
tool is limited to reporting information on JVMs for which it has the access permissions.
If jps is run without specifying a hostid, it will look for instrumented JVMs on the local host. If
started with a hostid, it will look for JVMs on the indicated host, using the specified protocol and
port. A jstatd process is assumed to be running on the target host.
The jps command will report the local VM identifier, or lvmid, for each instrumented JVM found on the
target system. The lvmid is typically, but not necessarily, the operating system's process identifier
for the JVM process. With no options, jps will list each Java application's lvmid followed by the
short form of the application's class name or jar file name. The short form of the class name or JAR
file name omits the class's package information or the JAR files path information.
The jps command uses the java launcher to find the class name and arguments passed to the main
method. If the target JVM is started with a custom launcher, the class name (or JAR file name) and
the arguments to the main method will not be available. In this case, the jps command will output the
string Unknown for the class name or JAR file name and for the arguments to the main method.
The list of JVMs produced by the jps command may be limited by the permissions granted to the princi-pal principal
pal running the command. The command will only list the JVMs for which the principle has access
rights as determined by operating system specific access control mechanisms.
NOTE - This utility is unsupported and may or may not be available in future versions of the JDK. It
is not currently available on Widows 98 and Windows ME platforms.
PARAMETERS
options Command-line options.
hostid The host identifier of the host for which the process report should be generated. The
hostid may include optional components that indicate the communications protocol, port
number, and other implementation specific data.
OPTIONS
The jps command supports a number of options that modify the output of the command. These options
are subject to change or removal in the future.
-q Suppress the output of the class name, JAR file name, and arguments passed to the main
method, producing only a list of local VM identifiers.
-m Output the arguments passed to the main method. The output may be null for embedded
JVMs.
-l Output the full package name for the application's main class or the full path name to
the application's JAR file.
-v Output the arguments passed to the JVM.
-V Output the arguments passed to the JVM through the flags file (the .hotspotrc file or
the file specified by the -XX:Flags=<filename> argument).
-Joption Pass option to the java launcher called by javac. For example, -J-Xms48m sets the
startup memory to 48 megabytes. It is a common convention for -J to pass options to
the underlying VM executing applications written in Java.
HOST IDENTIFIER
The host identifier, or hostid is a string that indicates the target system. The syntax of the hostid
string largely corresponds to the syntax of a URI:
[protocol:][[//]hostname][:port][/servername]
protocol The communications protocol. If the protocol is omitted and a hostname is not speci-fied, specified,
fied, the default protocol is a platform specific, optimized, local protocol. If the
protocol is omitted and a hostname is specified, then the default protocol is rmi.
hostname A hostname or IP address indicating the target host. If hostname is omitted, then the
target host is the local host.
port The default port for communicating with the remote server. If the hostname is omitted
or the protocol specifies an optimized, local protocol, then port is ignored. Other-wise, Otherwise,
wise, treatment of the port parameter is implementation specific. For the default rmi
protocol the port indicates the port number for the rmiregistry on the remote host. If
port is omitted, and protocol indicates rmi, then the default rmiregistry port (1099)
is used.
servername The treatment of this parameter depends on the implementation. For the optimized,
local protocol, this field is ignored. For the rmi protocol, this parameter is a
string representing the name of the RMI remote object on the remote host. See the -n
option for the jstatd command.
OUTPUT FORMAT
The output of the jps command follows the following pattern:
lvmid [ [ classname | JARfilename | "Unknown"] [ arg* ] [ jvmarg* ] ]
Where all output tokens are separated by white space. An arg that includes embedded white space will
introduce ambiguity when attempting to map arguments to their actual positional parameters.
NOTE- You are advised not to write scripts to parse jps output since the format may change in future
releases. If you choose to write scripts that parse jps output, expect to modify them for future
releases of this tool.
EXAMPLES
This section provides examples of the jps command.
Listing the instrumented JVMs on the local host:
jps
18027 Java2Demo.JAR
18032 jps
18005 jstat
Listing the instrumented JVMs on a remote host:
This example assumes that the jstat server and either the its internal RMI registry or a separate
external rmiregistry process are running on the remote host on the default port (port 1099). It also
assumes that the local host has appropriate permissions to access the remote host. This example also
includes the -l option to output the long form of the class names or JAR file names.
jps -l remote.domain
3002 /opt/j2sdk1.5.0/demo/jfc/Java2D/Java2Demo.JAR
2857 sun.tools.jstatd.jstatd
Listing the instrumented JVMs on a remote host with a non-default port for the RMI registry:
This example assumes that the jstatd server, with an internal RMI registry bound to port 2002, is
running on the remote host. This example also uses the -m option to include the arguments passed to
the main method of each of the listed Java applications.
jps -m remote.domain:2002
3002 /opt/j2sdk1.5.0/demo/jfc/Java2D/Java2Demo.JAR
3102 sun.tools.jstatd.jstatd -p 2002
SEE ALSO
java(1) jstat(1) jstatd(1) rmiregistry(1)
13 June 2004 jps(1)
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