So, suppose you have a java application and you want to test for performance issues that may occur such as delay in page loading and things like that. XRebel is here to help you manage this. XRebel is as Zeroturnaround says a lightweight java profiler. Really it is! You can try it from here and within 5 mins you can check the following:

• Page loading and class loading
• Which exactly sql queries are executed and how much time they take
• How much are your session data and if they are growing

You will be surprised with the easy of usage of this excellent tool