Simplest workaround: don't enable caching from the hibernate configuration you use in the tools (doesn't make much sense anyway).
It's most likely caused by you using Hibernate 3.6 or newer which has API changes that can cause problems.
I also noticed the error: java.lang.NoSuchMethodError: net.sf.ehcache.config.CacheConfiguration.isTerracottaClustered () Z
With hibernate 3.6.9, ehcache-core-2.5.0 and HT plugin for eclipse org.jboss.tools.hibernate4_0_3.4.0.v20111221-0406-H613-Beta1
When using Hibernate Tools in Eclipse. I share the configuration between Hibernate Tools and my project settings.
I found at http://javahigh1.iteye.com/blog/1205893 a solution (thanks to google translate), I like to share (In is inlike with the remark of Max).
Do not use the new property:
<property name="hibernate.cache.region.factory_class" value="net.sf.ehcache.hibernate.EhCacheRegionFactory"/>
but the old one:
<property name="hibernate.cache.provider_class" value="net.sf.ehcache.hibernate.EhCacheProvider"/>
in your configuration.