Same problem here!
Even defining Eclipse Kepler to use JDK 8 EA to run..
I know this thread is a bit old, but I just lost 3 hours trying to solve this problem and finally managed to
So, if it can be usefull to anyone, I share.
It seemsthat in order to use Hibernate Generation with jdk8 you have to install java 8 support for eclipse kepler.
See this link for the installation guide :
hope it helps.
Thanks that helped !!!!