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| .TH "JMAP" "1" "2020" "JDK 15" "JDK Commands" |
| .hy |
| .SH NAME |
| .PP |
| jmap \- print details of a specified process |
| .SH SYNOPSIS |
| .PP |
| \f[B]Note:\f[R] This command is experimental and unsupported. |
| .PP |
| \f[CB]jmap\f[R] [\f[I]options\f[R]] \f[I]pid\f[R] |
| .TP |
| .B \f[I]options\f[R] |
| This represents the \f[CB]jmap\f[R] command\-line options. |
| See \f[B]Options for the jmap Command\f[R]. |
| .RS |
| .RE |
| .TP |
| .B \f[I]pid\f[R] |
| The process ID for which the information specified by the |
| \f[I]options\f[R] is to be printed. |
| The process must be a Java process. |
| To get a list of Java processes running on a machine, use either the |
| \f[CB]ps\f[R] command or, if the JVM processes are not running in a |
| separate docker instance, the \f[B]jps\f[R] command. |
| .RS |
| .RE |
| .SH DESCRIPTION |
| .PP |
| The \f[CB]jmap\f[R] command prints details of a specified running process. |
| .PP |
| \f[B]Note:\f[R] |
| .PP |
| This command is unsupported and might not be available in future |
| releases of the JDK. |
| On Windows Systems where the \f[CB]dbgeng.dll\f[R] file isn\[aq]t present, |
| the Debugging Tools for Windows must be installed to make these tools |
| work. |
| The \f[CB]PATH\f[R] environment variable should contain the location of |
| the \f[CB]jvm.dll\f[R] file that\[aq]s used by the target process or the |
| location from which the core dump file was produced. |
| .SH OPTIONS FOR THE JMAP COMMAND |
| .TP |
| .B \f[CB]\-clstats\f[R] \f[I]pid\f[R] |
| Connects to a running process and prints class loader statistics of Java |
| heap. |
| .RS |
| .RE |
| .TP |
| .B \f[CB]\-finalizerinfo\f[R] \f[I]pid\f[R] |
| Connects to a running process and prints information on objects awaiting |
| finalization. |
| .RS |
| .RE |
| .TP |
| .B \f[CB]\-histo\f[R][\f[CB]:live\f[R]] \f[I]pid\f[R] |
| Connects to a running process and prints a histogram of the Java object |
| heap. |
| If the \f[CB]live\f[R] suboption is specified, it then counts only live |
| objects. |
| .RS |
| .RE |
| .TP |
| .B \f[CB]\-dump:\f[R]\f[I]dump_options\f[R] \f[I]pid\f[R] |
| Connects to a running process and dumps the Java heap. |
| The \f[I]dump_options\f[R] include: |
| .RS |
| .IP \[bu] 2 |
| \f[CB]live\f[R] \-\-\- When specified, dumps only the live objects; if not |
| specified, then dumps all objects in the heap. |
| .IP \[bu] 2 |
| \f[CB]format=b\f[R] \-\-\- Dumps the Java heap in \f[CB]hprof\f[R] binary |
| format |
| .IP \[bu] 2 |
| \f[CB]file=\f[R]\f[I]filename\f[R] \-\-\- Dumps the heap to |
| \f[I]filename\f[R] |
| .PP |
| Example: \f[CB]jmap\ \-dump:live,format=b,file=heap.bin\f[R] \f[I]pid\f[R] |
| .RE |
