Looking for an Appropriate Performance Measurement Tool

When I look for performance measurement took in Java, I see there are many good ones and it's easy to get confused which to use. For web applications I have used Apache JMeter for functional testing few weeks back. Now I am trying to measure how much time it takes for a specific method to finish execution for a large number of times - let's say 1000 times. I have no way to make direct call to that functions as the call will happen as part of a UI event, let's say button click, which amongst others also calls that function.

Can you think of an Appropriate Performance Measurement Tool for this scenario? I am looking for only free or open source projects and not the commercial ones like JProbe. When I google I see a few names like VisualVM, Jensor etc. What do you think about these? What are your other recommendations?

Thanks in advance.

here is a lisst of tools. http://www.javaperformancetuning.com/tools/index.shtml

jamon may be able to help, especially if it is web/jdbc app