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jmap(1)                                                                                              jmap(1)



NAME
       jmap - memory map

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

DESCRIPTION
       jmap  prints  shared  object  memory  maps  or heap memory details of a given process or core file or
       remote debug server.

       NOTE - This utility is unsupported and may or may not be available in future  versions  of  the  J2SE
       SDK.  jmap is not currently available on Windows platforms or on the Linux Itanium platform.

PARAMETERS
       option         Options  are  mutually  exclusive. Option, if used, shouldfollow 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.

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.

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

       -histo         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.

       -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.

       -h             Prints a help message.

       -help          Prints a help message.

SEE ALSO
       pmap(1) jps(1) jsadebugd(1)



                                                13 June 2004                                         jmap(1)