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Tuning JVM Memory Settings

The following is a few options available to tune the JVM:

   -Xms<size>   set initial Java heap size
   -Xmx<size>   set maximum Java heap size
   -Xss<size>   set java thread stack size

Example:

# java -Xms64m -Xmx256m HelloWorld

The following command will list all available options that can be set:

$ java -X
    -Xmixed           mixed mode execution (default)
    -Xint             interpreted mode execution only
    -Xbootclasspath:
                      set search path for bootstrap classes and resources
    -Xbootclasspath/a:
                      append to end of bootstrap class path
    -Xbootclasspath/p:
                      prepend in front of bootstrap class path
    -Xdiag            show additional diagnostic messages
    -Xnoclassgc       disable class garbage collection
    -Xincgc           enable incremental garbage collection
    -Xloggc:    log GC status to a file with time stamps
    -Xbatch           disable background compilation
    -Xms        set initial Java heap size
    -Xmx        set maximum Java heap size
    -Xss        set java thread stack size
    -Xprof            output cpu profiling data
    -Xfuture          enable strictest checks, anticipating future default
    -Xrs              reduce use of OS signals by Java/VM (see documentation)
    -Xcheck:jni       perform additional checks for JNI functions
    -Xshare:off       do not attempt to use shared class data
    -Xshare:auto      use shared class data if possible (default)
    -Xshare:on        require using shared class data, otherwise fail.
    -XshowSettings    show all settings and continue
    -XshowSettings:all
                      show all settings and continue
    -XshowSettings:vm show all vm related settings and continue
    -XshowSettings:properties
                      show all property settings and continue
    -XshowSettings:locale
                      show all locale related settings and continue

The -X options are non-standard and subject to change without notice.



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