1JMAP(1) JDK Commands JMAP(1)
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6 jmap - print details of a specified process
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9 Note: This command is experimental and unsupported.
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11 jmap [options] pid
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13 options
14 This represents the jmap command-line options. See Options for
15 the jmap Command.
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17 pid The process ID for which the information specified by the op‐
18 tions is to be printed. The process must be a Java process. To
19 get a list of Java processes running on a machine, use either
20 the ps command or, if the JVM processes are not running in a
21 separate docker instance, the jps command.
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23 Note: JDK 10 has added support for using the Attach API when at‐
24 taching to Java processes running in a separate docker process.
25 However, the jps command will not list the JVM processes that
26 are running in a separate docker instance. If you are trying to
27 connect a Linux host with a Virtual Machine that is in a docker
28 container, you must use tools such as ps to look up the PID of
29 the JVM.
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32 The jmap command prints details of a specified running process.
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34 Note:
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36 This command is unsupported and might not be available in future re‐
37 leases of the JDK. On Windows Systems where the dbgeng.dll file isn't
38 present, the Debugging Tools for Windows must be installed to make
39 these tools work. The PATH environment variable should contain the lo‐
40 cation of the jvm.dll file that's used by the target process or the lo‐
41 cation from which the core dump file was produced.
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44 -clstats pid
45 Connects to a running process and prints class loader statistics
46 of Java heap.
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48 -finalizerinfo pid
49 Connects to a running process and prints information on objects
50 awaiting finalization.
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52 -histo[:live] pid
53 Connects to a running process and prints a histogram of the Java
54 object heap. If the live suboption is specified, it then counts
55 only live objects.
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57 -dump:dump_options pid
58 Connects to a running process and dumps the Java heap. The
59 dump_options include:
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61 · live --- When specified, dumps only the live objects; if not
62 specified, then dumps all objects in the heap.
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64 · format=b --- Dumps the Java heap in hprof binary format
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66 · file=filename --- Dumps the heap to filename
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68 Example: jmap -dump:live,format=b,file=heap.bin pid
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72JDK 13 2018 JMAP(1)