I am using netbeans profiler (milestone 5) to investigate memory leaks in
our server code. I attach the profiler as follows -

  * Record both object creation and garbage collection
  * Take sample every "1" object allocations.

With this setup, the profiler always reports certain types of objects in
our system as "live". Obviously, at first I thought this was a genuine
memory leak in our application. However after an exhastive search for
the rogue references, I am convinced that this is in fact a profiler
issue.

To prove this, I wrote a simple "reference tracker" tool to get a second
opinion on these supposed memory leaks. My reference tracker uses
java.lang.WeakReference to monitor the objects. It periodically calls
System.gc() to flush out any expired objects and then uses
"WeakReference.get() == null" to check for liveness. Following are some
of the observations made using this tool -

1. If I run the test without attaching the netbeans profiler, the reference
   tracker shows all the objects getting freed at the appropriate time.

2. If I repeat the same test with netbeans profiler, then both the profiler
   and my reference tracker show that the objects are "live"! However if
   I then click on "Reset Results Buffer", the "reference tracker"
   immediately shows the objects getting freed.

3. Same thing happens if I detach the profiler. As soon as the profiler
   is detached, the "reference checker" reports the objects as
   unreachable.

4. Finally, if I use the netbeans profiler as just a heap monitor (i.e.
   without any instrumentation)  and run the test in a loop, it does not
   show any growth in the heap usage.


Please let me know if there is anything else I can do to help.