Maybe this will help anybody in an web environment (Persistence Manager is not
synchronized and not intended to use in Multithread environments)
http://weblogs.java.net/blog/ss141213/archive/2005/12/index.html
View the original post :
http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3983
Did you ever figure this out or get an answer? I have the same problem "all of
a sudden" EJB3 CMP entity beans are failing with the same error you had "
javax.ejb.EJBException: java.lang.IllegalArgumentException: Unknown entity: __"
when I call em.persist(MyCMPBean) from the session bean. Don
