Steve McKay, I tried running the 4.3 hibernate-entitymanager unit tests using -Dhibernate.ejb.use_class_enhancer=true, but there were no failures.

Were you able to reproduce the NPE using the hibernate-entitymanager tests? If not, can you create a pull request that will reproduce your failure?

I built using jdk 1.7:
java version "1.7.0_51"
Java(TM) SE Runtime Environment (build 1.7.0_51-b13)
Java HotSpot(TM) 64-Bit Server VM (build 24.51-b03, mixed mode)

I ran the 4.3 unit tests using jdk 1.8:
java version "1.8.0_40"
Java(TM) SE Runtime Environment (build 1.8.0_40-b26)
Java HotSpot(TM) 64-Bit Server VM (build 25.40-b25, mixed mode)
:
What version did you use?