Back-tracing references

Question

Is there a way to �back-trace� a reference?
In other words, can I find which object �A� has a reference to my object �B� and prevents it from being garbage-collected?
I have a program which doesn�t garbage-collect some objects, even though I force it with
System.runFinalization();
System.gc();
�and I can�t find out why!

Answer 1

1. Use a memory inspector e.g., JProbe.
2. The timing of an object's collection is non-deterministic.. it may happen sooner, or later, or not at all. And System.gc() won't force anything but a penalty in your application's performance esp. considering all threads are suspended during a scan.
3. The use of finalizers should generally be considered bad practice. An object with a finalizer tends to loiter because of the extra steps the gc must perform (first in determining when to finalize and then when to collect) -- finalizers aggravate an already sticky memory management process. Refactor your system to use explicit destruction.