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6.6.36.0: Java command line arguments reference

6.6.36.0: Java command line arguments reference

This section provides a reference of Java Virtual Machine (JVM) command line arguments related to performance and debugging. The WebSphere administrator can configure application servers and other managed Java processes to start with these parameters as command line arguments.

Additional command line arguments are valid, beyond those listed in this section. For a list of the command line arguments currently available on your operating system with your Java Development Kit (JDK) level, type java or java -X at a system command prompt.

Command line arguments related to performance

Goal Argument Values Notes
Specify the maximum heap size the Java interpreter will use for dynamically allocated objects and arrays -Xmx Specify the value in bytes, with a value greater than 1000 On AIX, the default is 32M
Specify how much memory is allocated for the heap when the JVM starts -Xms Specify the value in bytes, with a value greater than 1000 On AIX, the default is 1M
Specify the size of each thread Java code stack -oss Specify the value in bytes, with a value greater than 1000 On AIX, the default is 400K
Specify the size of each thread native code stack -ss Specify the value in bytes, with a value greater than 1000 On AIX, the default value is 256K

Command line arguments related to debugging

Goal Argument Values Notes
Disable the JIT compiler -Djava.compile=none None Not available on AIX or Solaris
Specify whether to run the byte-code verifier on all loaded classes -verify true|false None
Verify classes read in over the network -verifyremote None None
Avoid verifying any classes -noverify None None
Specify whether to print a message whenever the garbage collector frees memory -verbosegc None None
Prevent asynchronous garbage collection -noasyncgc None None
Disable class garbage collection -Xnoclassgc None None
Specify whether to print a message each time the JVM loads a class -verbose None None
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