Hello,

I'm writing a unit test to better understand how criteria queries work in combination with Map member fields.
My UserGroup entity contains a domainAccessRights member, defined as Map<Domain, AccessRights>.
Now I want to select all UserGroups that contain a Domain with a certain oid in their domainAccessRights.
When running the text below I get this Exception:
org.hibernate.QueryException: cannot dereference scalar collection element: map [select generatedAlias0 from com.fugro.gwf.domain.model.v0.security.UserGroup as generatedAlias0 inner join generatedAlias0.domainAccessRights as generatedAlias1 where generatedAlias1.map-key.oid=:param0]
Does anyone know how I can fix this problem? Hibernate version is 4.2.8 ...

@Test
public void jpaCriteriaQueryForMaps_TestSecondExampleFromInternet()
{
CriteriaBuilder builder = entityManager.getCriteriaBuilder();
CriteriaQuery<UserGroup> criteria = builder.createQuery(UserGroup.class);
Root<UserGroup> root = criteria.from(UserGroup.class);
MapJoin<UserGroup, Domain, AccessRights> rights = root.join(UserGroup_.domainAccessRights);
criteria.where(builder.equal(rights.key().get(Domain_.oid), UserPopulationHandler.DOMAIN_FEBV_PROJECTS_OID));
List<UserGroup> resultList = entityManager.createQuery(criteria).getResultList();
Assert.assertEquals(1, resultList.size());
Assert.assertEquals(UserPopulationHandler.USERGROUP_FEBV_ADMIN_OID, resultList.get(0).getOid());
}