Configuring the Java Virtual Machine Software

After you have finished the required postinstallation configuration for your Java ES components, some Java ES components might require that you tune the Java Virtual Machine (JVM^TM) software. The JVM software consists of several entities, the most significant being the compiler, which turns Java byte code into machine instructions. In the version of the Java development kit (JDK^TM) software that is included with this Java ES release, several choices can be made for the JVM software. The best starting option is the –server option. The –server option is a good tuning option for a JVM running in server mode. You can obtain the list of options by using the java –? command.

Another significant tuning option that might need to be configured is the Java heap memory. For example:

• To set the initial Java heap size, use -Xmssize.

• To set the maximum Java heap size, use -Xmxsize.

A good starting point for a heavily used system would be to set the maximum heap size to 1.2 Gbytes.