1jmap(1)                      Troubleshooting Tools                     jmap(1)
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NAME

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

11       jmap [ options ] pid
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13       jmap [ options ] executable core
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15       jmap [ options ] [ pid ] server-id@ ] remote-hostname-or-IP
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18       options
19              The command-line options. See Options.
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21       pid    The process ID for which the memory map is to be printed. The
22              process must be a Java process. To get a list of Java processes
23              running on a machine, use the jps(1) command.
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25       executable
26              The Java executable from which the core dump was produced.
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28       core   The core file for which the memory map is to be printed.
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30       remote-hostname-or-IP
31              The remote debug server hostname or IP address. See
32              jsadebugd(1).
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34       server-id
35              An optional unique ID to use when multiple debug servers are
36              running on the same remote host.
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DESCRIPTION

39       The jmap command prints shared object memory maps or heap memory
40       details of a specified process, core file, or remote debug server. If
41       the specified process is running on a 64-bit Java Virtual Machine
42       (JVM), then you might need to specify the -J-d64 option, for example:
43       jmap-J-d64 -heap pid.
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45       Note: This utility is unsupported and might not be available in future
46       releases of the JDK. On Windows Systems where the dbgeng.dll file is
47       not present, Debugging Tools For Windows must be installed to make
48       these tools work. The PATH environment variable should contain the
49       location of the jvm.dll file that is used by the target process or the
50       location from which the crash dump file was produced, for example: set
51       PATH=%JDK_HOME%\jre\bin\client;%PATH%.
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OPTIONS

54       <no option>
55              When no option is used, the jmap command prints shared object
56              mappings. For each shared object loaded in the target JVM, the
57              start address, size of the mapping, and the full path of the
58              shared object file are printed. This behavior is similar to the
59              Oracle Solaris pmap utility.
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61       -dump:[live,] format=b, file=filename
62              Dumps the Java heap in hprof binary format to filename. The live
63              suboption is optional, but when specified, only the active
64              objects in the heap are dumped. To browse the heap dump, you can
65              use the jhat(1) command to read the generated file.
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67       -finalizerinfo
68              Prints information about objects that are awaiting finalization.
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70       -heap
71              Prints a heap summary of the garbage collection used, the head
72              configuration, and generation-wise heap usage. In addition, the
73              number and size of interned Strings are printed.
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75       -histo[:live]
76              Prints a histogram of the heap. For each Java class, the number
77              of objects, memory size in bytes, and the fully qualified class
78              names are printed. The JVM internal class names are printed with
79              an asterisk (*) prefix. If the live suboption is specified, then
80              only active objects are counted.
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82       -clstats
83              Prints class loader wise statistics of Java heap. For each class
84              loader, its name, how active it is, address, parent class
85              loader, and the number and size of classes it has loaded are
86              printed.
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88       -F
89              Force. Use this option with the jmap -dump or jmap -histo option
90              when the pid does not respond. The live suboption is not
91              supported in this mode.
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93       -h
94              Prints a help message.
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96       -help
97              Prints a help message.
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99       -Jflag
100              Passes flag to the Java Virtual Machine where the jmap command
101              is running.
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SEE ALSO

104       · jhat(1)
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106       · jps(1)
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108       · jsadebugd(1)
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112JDK 8                          21 November 2013                        jmap(1)
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