jmap(1)                    OpenBSD Reference Manual                    jmap(1)



NAME
       jmap - Memory Map

SYNOPSIS
       jmap [ option ] pid
       jmap [ option ] executable core
       jmap [ option ] [server-id@]remote-hostname-or-IP


PARAMETERS
       option
          Options are mutually exclusive. Option, if used, should follow
          immediately after the command name.

       pid
          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, jps may be used.

       executable
          Java executable from which the core dump was produced.

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

       remote-hostname-or-IP
          remote debug server's (see jsadebugd) hostname or IP address.

       server-id
          optional unique id, if multiple debug servers are running on the
          same remote host.


DESCRIPTION
       jmap prints shared object memory maps or heap memory details of a given
       process or core file or a remote debug server. If the given process is
       running on a 64-bit VM, you may need to specify the -J-d64 option,
       e.g.:

          jmap -J-d64 -heap pid


       NOTE - This utility is unsupported and may or may not be available in
       future versions of the JDK.


       The only forms of jmap available on the Windows platform are


          jmap -dump:<dump-options> pid
       and


          jmap -histo[:live] pid

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

       -dump:[live,]format=b,file=<filename>
          Dumps the Java heap in hprof binary format to filename. The live
          suboption is optional. If specified, only the live objects in the
          heap are dumped. To browse the heap dump, you can use jhat (Java
          Heap Analysis Tool) to read the generated file.

       -finalizerinfo
          Prints information on objects awaiting finalization.

       -heap
          Prints a heap summary. GC algorithm used, heap configuration and
          generation wise heap usage are printed.

       -histo[:live]
          Prints a histogram of the heap. For each Java class, number of
          objects, memory size in bytes, and fully qualified class names are
          printed. VM internal class names are printed with '*' prefix. If the
          live suboption is specified, only live objects are counted.

       -permstat
          Prints class loader wise statistics of permanent generation of Java
          heap. For each class loader, its name, liveness, address, parent
          class loader, and the number and size of classes it has loaded are
          printed. In addition, the number and size of interned Strings are
          printed.

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

       -h Prints a help message.

       -help
          Prints a help message.

       -J<flag>
          Passes <flag> to the Java virtual machine on which jmap is run.


SEE ALSO
          * pmap (1)

          * jhat

          * jps

          * jsadebugd


                                  05 Aug 2006                          jmap(1)
