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javamemory-managementjvmjvm-argumentsjvm-hotspot

Default for XX:MaxDirectMemorySize

What is the default value for XX:MaxDirectMemorySize?

Solution

  • From http://www.docjar.com/html/api/sun/misc/VM.java.html

    i see:

     163       // A user-settable upper limit on the maximum amount of allocatable direct
 164       // buffer memory.  This value may be changed during VM initialization if
 165       // "java" is launched with "-XX:MaxDirectMemorySize=<size>".
 166       //
 167       // The initial value of this field is arbitrary; during JRE initialization
 168       // it will be reset to the value specified on the command line, if any,
 169       // otherwise to Runtime.getRuntime.maxDirectMemory().
 170       //
 171       private static long directMemory = 64 * 1024 * 1024;

    so it appears to default to 64 megs.