JVM (GC) tuning useful links and Netbeans Heapwalker demo project

I want to add some useful document links which bring me up on this big topic--JVM (GC) tuning:
http://java.sun.com/javase/technologies/hotspot/gc/gc_tuning_6.html
http://java.sun.com/docs/hotspot/gc5.0/gc_tuning_5.html
http://java.sun.com/performance/reference/whitepapers/tuning.html
http://java.sun.com/j2se/1.5.0/docs/guide/vm/gc-ergonomics.html
http://java.sun.com/j2se/1.5/pdf/jdk50_ts_guide.pdf
http://java.sun.com/j2se/1.5.0/docs/guide/vm/server-class.html

For Heap dump analyzer, apart from Eclipse Memory Analyzer, there is another Cool free analyzer tool,Netbeans HeapWalker:
http://profiler.netbeans.org/docs/help/6.0/heapwalker.html

here is one very interesting HeapWalker Demo, for QA people who is interesting in trying to tune the performance memory issues, you may go through this message and get some sense of performance tuning by yourself :)

http://wiki.netbeans.org/HeapWalkerDemo