jmap(1)                      Troubleshooting Tools                     jmap(1)

       jmap - Prints shared object memory maps or heap memory details for a
       process, core file, or remote debug server. This command is
       experimental and unsupported.

       jmap [ options ] pid

       jmap [ options ] executable core

       jmap [ options ] [ pid ] server-id@ ] remote-hostname-or-IP

              The command-line options. See Options.

       pid    The process ID for which the memory map is to be printed. The
              process must be a Java process. To get a list of Java processes
              running on a machine, use the jps(1) command.

              The Java executable from which the core dump was produced.

       core   The core file for which the memory map is to be printed.

              The remote debug server hostname or IP address. See

              An optional unique ID to use when multiple debug servers are
              running on the same remote host.

       The jmap command prints shared object memory maps or heap memory
       details of a specified process, core file, or remote debug server. If
       the specified process is running on a 64-bit Java Virtual Machine
       (JVM), then you might need to specify the -J-d64 option, for example:
       jmap-J-d64 -heap pid.

       Note: This utility is unsupported and might not be available in future
       releases of the JDK. On Windows Systems where the dbgeng.dll file is
       not present, 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 is used by the target process or the
       location from which the crash dump file was produced, for example: set

       <no option>
              When no option is used, the jmap command prints shared object
              mappings. For each shared object loaded in the target JVM, the
              start address, size of the mapping, and the full path of the
              shared object file are printed. This behavior is similar to the
              Oracle Solaris pmap utility.

       -dump:[live,] format=b, file=filename
              Dumps the Java heap in hprof binary format to filename. The live
              suboption is optional, but when specified, only the active
              objects in the heap are dumped. To browse the heap dump, you can
              use the jhat(1) command to read the generated file.

              Prints information about objects that are awaiting finalization.

              Prints a heap summary of the garbage collection used, the head
              configuration, and generation-wise heap usage. In addition, the
              number and size of interned Strings are printed.

              Prints a histogram of the heap. For each Java class, the number
              of objects, memory size in bytes, and the fully qualified class
              names are printed. The JVM internal class names are printed with
              an asterisk (*) prefix. If the live suboption is specified, then
              only active objects are counted.

              Prints class loader wise statistics of Java heap. For each class
              loader, its name, how active it is, address, parent class
              loader, and the number and size of classes it has loaded are

              Force. Use this option with the jmap -dump or jmap -histo option
              when the pid does not respond. The live suboption is not
              supported in this mode.

              Prints a help message.

              Prints a help message.

              Passes flag to the Java Virtual Machine where the jmap command
              is running.

       · jhat(1)

       · jps(1)

       · jsadebugd(1)

JDK 8                          21 November 2013                        jmap(1)