1jmap(1) Troubleshooting Tools jmap(1)
2
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.
9
11 jmap [ options ] pid
12 jmap [ options ] executable core
14 jmap [ options ] [ pid ] server-id@ ] remote-hostname-or-IP
16 options
19 The command-line options. See Options.
20 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.
24 executable
26 The Java executable from which the core dump was produced.
27 core The core file for which the memory map is to be printed.
29 remote-hostname-or-IP
31 The remote debug server hostname or IP address. See
32 jsadebugd(1).
33 server-id
35 An optional unique ID to use when multiple debug servers are
36 running on the same remote host.
37
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.
44 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%.
52
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.
60 -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.
66 -finalizerinfo
68 Prints information about objects that are awaiting finalization.
69 -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.
74 -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.
81 -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.
87 -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.
92 -h
94 Prints a help message.
95 -help
97 Prints a help message.
98 -Jflag
100 Passes flag to the Java Virtual Machine where the jmap command
101 is running.
102
104 · jhat(1)
105 · jps(1)
107 · jsadebugd(1)
109JDK 8 21 November 2013 jmap(1)