jmap(1)jmap(1)Namejmap - Memory Map
SYNOPSISjmap [ 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.
DESCRIPTIONjmap 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)
16 Mar 2012 jmap(1)
