1jmap(1) General Commands Manual jmap(1)
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6 jmap - Memory Map
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9 jmap [ option ] pid
10 jmap [ option ] executable core
11 jmap [ option ] [server-id@]remote-hostname-or-IP
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15 option
16 Options are mutually exclusive. Option, if used, should follow
17 immediately after the command name.
18 pid
20 process id for which the memory map is to be printed. The process
21 must be a Java process. To get a list of Java processes running
22 on a machine, jps(1) may be used.
23 executable
25 Java executable from which the core dump was produced.
26 core
28 core file for which the memory map is to be printed.
29 remote-hostname-or-IP
31 remote debug server's (see jsadebugd(1)) hostname or IP address.
32 server-id
34 optional unique id, if multiple debug servers are running on the
35 same remote host.
36
39 jmap prints shared object memory maps or heap memory details of a given
40 process or core file or a remote debug server. If the given process is
41 running on a 64-bit VM, you may need to specify the -J-d64 option,
42 e.g.:
43 jmap -J-d64 -heap pid
45 NOTE: This utility is unsupported and may or may not be available in
48 future versions of the JDK. In Windows Systems where dbgeng.dll is not
49 present, 'Debugging Tools For Windows' needs to be installed to have
50 these tools working. Also, PATH environment variable should contain the
51 location of jvm.dll used by the target process or the location from
52 which the Crash Dump file was produced.
53 For example, set PATH=<jdk>\jre\bin\client;%PATH%
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57 <no option>
58 When no option is used jmap prints shared object mappings. For
59 each shared object loaded in the target VM, start address, the
60 size of the mapping, and the full path of the shared object file
61 are printed. This is similar to the Solaris pmap utility.
62 -dump:[live,]format=b,file=<filename>
64 Dumps the Java heap in hprof binary format to filename. The live
65 suboption is optional. If specified, only the live objects in the
66 heap are dumped. To browse the heap dump, you can use jhat(1)
67 (Java Heap Analysis Tool) to read the generated file.
68 -finalizerinfo
70 Prints information on objects awaiting finalization.
71 -heap
73 Prints a heap summary. GC algorithm used, heap configuration and
74 generation wise heap usage are printed.
75 -histo[:live]
77 Prints a histogram of the heap. For each Java class, number of
78 objects, memory size in bytes, and fully qualified class names
79 are printed. VM internal class names are printed with '*' prefix.
80 If the live suboption is specified, only live objects are
81 counted.
82 -permstat
84 Prints class loader wise statistics of permanent generation of
85 Java heap. For each class loader, its name, liveness, address,
86 parent class loader, and the number and size of classes it has
87 loaded are printed. In addition, the number and size of interned
88 Strings are printed.
89 -F Force. Use with jmap -dump or jmap -histo option if the pid does
91 not respond. The live suboption is not supported in this mode.
92 -h Prints a help message.
94 -help
96 Prints a help message.
97 -J<flag>
99 Passes <flag> to the Java virtual machine on which jmap is run.
100
103 o pmap(1)
104 o jhat(1)
106 o jps(1)
108 o jsadebugd(1)
110 16 Mar 2012 jmap(1)