I've stumbled across the same issue, JAXBContext.newInstance( modelClass ); is called for every hbm.xml-file that is mapped, slowing down the startup of my application significantly.

I tried versions 5.0.0, 5.0.1 and 5.0.2. The problem remains till now, although it is marked as fixed in 5.0,1. Did I miss anything (I am quite new to hibernate and JiRA in gereral)?