With WMQ, an IBM Java environment is shipped with a number of platforms. If you’re developing JMS or WMQ Java Classes Client applications, it is well worth taking the time to scan the Diagnostics Guide that is available on developerWorks.

To give you an idea of the type of things this contains..

Java Heap Dumps- information on how to (a) produce one of these dumps yourself, and (b) how to understand the output. These can be very useful if you have a thread lock and need to work out what is locking what

Class Loading – Every wondered where that class was being (or not being) loaded from? Try this out.

Apologies for the slighly non-WMQ post.. but I thought this is very valuable information. Most WMQ users will be using a IBM JVM (or not?? please correct me!)