Set the following attributes of the jvm element in the server.xml file:
Set debug="true" to turn on debugging.
Add any desired JPDA debugging options in the debugoptions attribute. See JPDA Options.
To specify the port to use when attaching the JVM to a debugger. Specify address=port_number in the debugoptions attribute.
For details about the server.xml file, see the Sun Java System Web Server 7.0 Update 4 Administrator’s Configuration File Reference.