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Arch: generic
Software: JDK 8
Date: 21 November 2013
SectDesc: Troubleshooting Tools
Title: jhat.1
* Define some portability stuff
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http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
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* set default formatting
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jhat [ options ] heap-dump-file
options The command-line options. See Options.
heap-dump-file Java binary heap dump file to be browsed. For a dump file that contains multiple heap dumps, you can specify which dump in the file by appending \f3#<number> to the file name, for example, \f3myfile.hprof#3.
There are several ways to generate a Java heap dump:
0.2i Use the \f3jmap -dump option to obtain a heap dump at runtime. See jmap(1).
0.2i Use the \f3jconsole option to obtain a heap dump through \f3HotSpotDiagnosticMXBean at runtime. See jconsole(1) and the \f3HotSpotDiagnosticMXBean interface description at http://docs.oracle.com/javase/8/docs/jre/api/management/extension/com/sun/management/HotSpotDiagnosticMXBean.html
0.2i Heap dump is generated when an \f3OutOfMemoryError is thrown by specifying the \f3-XX:+HeapDumpOnOutOfMemoryError Java Virtual Machine (JVM) option.
0.2i Use the \f3hprof command. See the HPROF: A Heap/CPU Profiling Tool at http://docs.oracle.com/javase/8/docs/technotes/samples/hprof.html
-stack false|true
Turns off tracking object allocation call stack. If allocation site information is not available in the heap dump, then you have to set this flag to \f3false. The default is \f3true.
-refs false|true
Turns off tracking of references to objects. Default is \f3true. By default, back pointers, which are objects that point to a specified object such as referrers or incoming references, are calculated for all objects in the heap.
-port port-number
Sets the port for the \f3jhat HTTP server. Default is 7000.
-exclude exclude-file
Specifies a file that lists data members that should be excluded from the reachable objects query. For example, if the file lists \f3java.lang.String.value, then, then whenever the list of objects that are reachable from a specific object \f3o are calculated, reference paths that involve \f3java.lang.String.value field are not considered.
-baseline exclude-file
Specifies a baseline heap dump. Objects in both heap dumps with the same object ID are marked as not being new. Other objects are marked as new. This is useful for comparing two different heap dumps.
-debug int
Sets the debug level for this tool. A level of 0 means no debug output. Set higher values for more verbose modes.
-version
Reports the release number and exits
-h
Dsiplays a help message and exits.
-help
Displays a help message and exits.
-Jflag
Passes \f3flag to the Java Virtual Machine on which the \f3jhat command is running. For example, \f3-J-Xmx512m to use a maximum heap size of 512 MB.
0.2i jmap(1)
0.2i jconsole(1)
0.2i HPROF: A Heap/CPU Profiling Tool at http://docs.oracle.com/javase/8/docs/technotes/samples/hprof.html
'pl 8.5i 'bp