Configuring the Java Virtual Machine (JVM)

After you have finished the required postinstallation configuration for your Java ES product components, some product components might require that you tune the Java Virtual Machine (JVM). The JVM consists of several entities, the most significant being the compiler, which turns Java byte code into machine instructions. In the version of the Java Developer's Kit (JDK) that is included with Java ES, there are several choices which can be made for the JVM.

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.)

For garbage collection, the default algorithm is a good place to start.

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

• The following command sets the initial Java heap size: -Xmssize

• The following command sets the maximum Java heap size: -Xmxsize

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