I found that if you pass the -Xrs flag to the JVM (1.3.1 and earlier) parameters while creating the JVM, then the shutdown hook will NOT be called. This might be because -Xrs reduces use of OS signals by Java/VM.

Just so you know.

I tried using this flag with JDK 1.4.2_6 and found that INSPITE of the flag, the program worked as advertised.

BR,
~A