Found workaround: use following settings for persistence unit (persistence.xml): property name="hibernate.cache.provider_class" value="net.sf.ehcache.hibernate.EhCacheProvider" property name="net.sf.ehcache.configurationResourceName" value="_ehcache.xml" such config allows put ehcache lib into ear, without any class loading problems. View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4264975#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...