JPA exception: Object: … is not a known entity type

Question

I\'m new to JPA and I\'m having problems with the autogeneration of primary key values.

I have the following entity:

package jpatest.entities;

impor         


        

Answer 1

I ran into this same problem using NetBeans IDE 6.9.

Apparently, this is a known issue. See http://wiki.eclipse.org/EclipseLink/Development/JPA_2.0/metamodel_api#DI_101:_20100218:_Descriptor.javaClass_is_null_on_a_container_EM_for_a_specific_case. Also see http://netbeans.org/bugzilla/show_bug.cgi?id=181068.

I added the last line below to persistence.xml and it fixed it for me.

org.eclipse.persistence.jpa.PersistenceProvider

false