JVM performance tuning for large applications

Question

The default JVM parameters are not optimal for running large applications. Any insights from people who have tuned it on a real application would be helpful. We are running the

Answer 1

The absolute best way to answer this is to perform controlled testing on the application in as close to a 'production' environment as you can create. It's quite possible that the use of -server, a reasonable starting heap size and the relatively smart behavior of recent JVMs will behave as well or better than the vast majority of settings one would normally try.

There is one specific exception to this broad generalization: in the case that you are running in a web container, there is a really high chance that you will want to increase the permanent generation settings.