Performance help for CQ5 content management system

The content management team has asked me to help them in finding the performance issue they are having with CQ5. The problem seems to be of high CPU usage and after a while the server stops responding. The system admins do not have experience in Java and it seems the Java process is taking almost all of the CPU. They could not find which threads or methods are causing this.

Which type of tool/profiling would be of help here? I would like to find out which classes/methods are causing the CPU load increase. But since this being a deployed application (we did not develop this app) and the customer support wanting more information, what would be a starting point? Would tools which have the memory profiling or cpu profiling help?

P.S. - I have not personally seen nor do I have any working experience in CQ5. I just want to be prepared when we sit for debugging.

Thanks.

The problem seems to be of high CPU usage and after a while the server stops responding.

Sounds like an endless major garbage collection loop could be a possibility. Poorly written code that has entered an infinite loop is another possibility.

Taking a stack dump (http://java.sun.com/developer/technicalArticles/Programming/Stacktrace/) would pinpoint application loops.

Monitoring the garbage collection stats would aid in determining if you are in a major collection loop, and either increasing the heap size or tracking down memory leaps in the application would fix that. See this presentation i did to get started on monitoring GC stats: http://www.cecmg.de/doc/tagung_2007/agenda07/24-mai/2b3-peter-johnson/index.html