Check out www.javaperformancetuning.com for lots of resources on java performance. There are links to tools, books, articles and other things relavant to java performance.
I have a 90K jar available on the website that can aid in performance tuning and monitoring. It couldn't be easier to use and provides a wealth of information including performance and scalability statistics and more. Other features include the ability to monitor production java code, and to disable monitoring at runtime.
A link with a typical sample data:
To learn about and download JAMon go to: