How to test java application for performance bottlenecks?

Question

I am reviewing a big java application to see if there are any performance bottlenecks. The real problem is that I cannot pinpoint the performance issues to any single module. The whole application is slow as such.

Is there some tool/technique I can use to help me out in this?

Answer 1

I'm often happy enough using Java -Xprof. This gives you a sorted list of the functions your code spends most of its time in.

Answer 2

Try using a profiler on your running code. It should help you identify the bottlenecks. Try jprofiler or Netbeans profiler