JProfiler or some other profiler product would tell you where you're spending those precious CPU cycles, memory, and about how your application's threads behave. If you don't want to spend $$$ on the profiler, try this Eclipse plugin. There are others, of course.
It is important to quantify system performance and to identify your performance goals before deciding how to go about reaching them. If you don't know how fast the system needs to be, then how do you know when you've reached that point?
I strongly recommend specifying a performance goal, like this:
The system must respond within 750 ms, 90% of the time, with a load of 100 users.
Just change the numbers. The nice thing about this is, not only do you have a specific goal, but you can write a test for it!
Author of <a href="http://www.amazon.com/exec/obidos/ASIN/1932394230/ref=jranch-20" target="_blank" rel="nofollow">JUnit Recipes: Practical Methods for Programmer Testing</a>
Joined: Jan 23, 2002
Originally posted by somkiat puisungnoen: Which are best monitor tool used in java/j2ee application ??
If you're looking for products in "the bigger the better" category, then I guess Mercury LoadRunner is number one. The scripting facilities are horrible but relatively feature rich. Things might've changed in the newer versions.
In the profiler category, the best selling products are probably JProbe and Optimizeit. JProfiler has also been showing up here and there lately.