jmap(1)                     General Commands 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(1) 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(1)) 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. In Windows Systems where dbgeng.dll is not
       present, 'Debugging Tools For Windows' needs to be  installed  to  have
       these tools working. Also, PATH environment variable should contain the
       location of jvm.dll used by the target process  or  the  location  from
       which the Crash Dump file was produced.

       For example, set PATH=<jdk>\jre\bin\client;%PATH%

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(1)
             (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
          o pmap(1)

          o jhat(1)

          o jps(1)

          o jsadebugd(1)


                                  18 Jul 2013                          jmap(1)
