Just crossed this interesting post on Oracle’s blog on Enterprise Manager. When you are in to optimizing your JVMs you might want to take a look at it….
Tuning a production JVM involves more than merely adding more RAM to it via the -Xmx parameter. It depends upon an understanding of how your application truly behaves in a production environment. Most JVM tuning is done by developers with a simulated load in their Development or QA environment. This is unlikely to be truly representative of the production load running on production hardware with regards to proper JVM tuning.