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JMAP(1) JDK Commands JMAP(1)


jmap - print details of a specified process


Note: This command is experimental and unsupported.

jmap [options] pid

This represents the jmap command-line options. See Options for the jmap Command.
The process ID for which the information specified by the options is to be printed. The process must be a Java process. To get a list of Java processes running on a machine, use either the ps command or, if the JVM processes are not running in a separate docker instance, the jps command.

Note: JDK 10 has added support for using the Attach API when attaching to Java processes running in a separate docker process. However, the jps command will not list the JVM processes that are running in a separate docker instance. If you are trying to connect a Linux host with a Virtual Machine that is in a docker container, you must use tools such as ps to look up the PID of the JVM.


The jmap command prints details of a specified running process.


This command is unsupported and might not be available in future releases of the JDK. On Windows Systems where the dbgeng.dll file isn't present, the Debugging Tools for Windows must be installed to make these tools work. The PATH environment variable should contain the location of the jvm.dll file that's used by the target process or the location from which the core dump file was produced.


-clstats pid
Connects to a running process and prints class loader statistics of Java heap.
-finalizerinfo pid
Connects to a running process and prints information on objects awaiting finalization.
-histo[:live] pid
Connects to a running process and prints a histogram of the Java object heap. If the live suboption is specified, it then counts only live objects.
-dump:dump_options pid
Connects to a running process and dumps the Java heap. The dump_options include:
live --- When specified, dumps only the live objects; if not specified, then dumps all objects in the heap.
format=b --- Dumps the Java heap in hprof binary format
file=filename --- Dumps the heap to filename

Example: jmap -dump:live,format=b,file=heap.bin pid

2018 JDK 13