Stopwatch is a simple, highly extensible, API that alows monitoring of any part of the application. It reports hits, execution times and load but can be extended to do more via custom engines. It is able to persist data in "in-memory" or real database.
Jdptool is a debug and profiler tool which based on JPDA; It provide both swing based and browser based GUI. It has sophisticated debugger without user interfere. It also provide profiler to memory usage and threads with numerous new feature
JMonitoring and NMonitoring are monitoring frameworks for Java and .Net applications, based on AOP (AspectJ and AspectDNG). Data are stored in database, memory or XML and can be consulted with a web console. http://forge.octo.com/confluence/display/JMO