Classloader issues - How to determine which library versions (jar-files) are loaded

Question

I\'ve just solved another *I-though-I-was-using-this-version-of-a-library-but-apparently-my-app-server-has-already-loaded-an-older-version-of-this-library-*issue (sigh).

Answer 1

If you happen to be using JBoss, there is an MBean (the class loader repository iirc) where you can ask for all classloaders that have loaded a certain class.

If all else fails, there's always 'java -verbose:class' which will print the location of the jar for every class file that is being loaded.