Try hprof. It is freely with jsdk. If you type
java -Xrunhprof:help you will get a help screen on how to use.
I also recommend this link which gives some tutorial on how to use it:
<a href="http://developer.java.sun.com/developer/onlineTraining/Programming/JDCBook/perf3.html#profile<a href="http://developer.java.sun.com/developer/onlineTraining/Programming/JDCBook/perf3.html#profile" target="_blank" rel="nofollow">Advanced" target="_blank">
http://developer.java.sun.com/developer/onlineTraining/Programming/JDCBook/perf3.html#profile[URL=http://developer.java.sun.com/developer/onlineTraining/Programming/JDCBook/perf3.html#profile]Advanced Programming for the JavaTM 2 Platform - Profiling