IdClass and mappedBy problem ---------------------------- Key: HHH-6555 URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-6555 Project: Hibernate Core Issue Type: Bug Affects Versions: 4.0.0.Beta4, 3.6.6, 4.0.0.Beta2 Environment: Derby 10.8.1.2 Reporter: Piotr Gliźniewicz I have the following classes: {code}@Entity public class SimpleEntity { @Id private int id; @OneToOne(cascade = CascadeType.ALL, mappedBy = "entityA") private EntityConnection connection; @OneToMany(cascade = CascadeType.ALL, mappedBy = "entityB") private List<EntityConnection> otherConnections; // accessors }{code} {code}@Entity @IdClass(EntityConnectionPK.class) public class EntityConnection { @Id @JoinColumn(name = "entity_a_id") @OneToOne private SimpleEntity entityA; @Id @JoinColumn(name = "entity_b_id") @ManyToOne private SimpleEntity entityB; // accessors }{code} {code}public class EntityConnectionPK implements Serializable { private int entityA; private int entityB; // accessors, equals, hashcode }{code} Executing the following query: {code} TypedQuery<SimpleEntity> q = em.createQuery("select e from SimpleEntity e where e.id = 1", SimpleEntity.class); SimpleEntity foundEntity = q.getResultList().get(0); {code} results in: {code}Exception in thread "main" java.lang.NullPointerException at org.hibernate.persister.entity.AbstractEntityPersister.loadByUniqueKey(AbstractEntityPersister.java:2200) at org.hibernate.type.EntityType.loadByUniqueKey(EntityType.java:661) at org.hibernate.type.EntityType.resolve(EntityType.java:441) at org.hibernate.engine.internal.TwoPhaseLoad.initializeEntity(TwoPhaseLoad.java:150) at org.hibernate.loader.Loader.initializeEntitiesAndCollections(Loader.java:1012) at org.hibernate.loader.Loader.doQuery(Loader.java:889) at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:289) at org.hibernate.loader.Loader.doList(Loader.java:2449) at org.hibernate.loader.Loader.doList(Loader.java:2435) at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2276) at org.hibernate.loader.Loader.list(Loader.java:2271) at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:470) at org.hibernate.hql.internal.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:355) at org.hibernate.engine.query.spi.HQLQueryPlan.performList(HQLQueryPlan.java:196) at org.hibernate.internal.SessionImpl.list(SessionImpl.java:1105) at org.hibernate.internal.QueryImpl.list(QueryImpl.java:100) at org.hibernate.ejb.QueryImpl.getResultList(QueryImpl.java:252){code} After some debugging I found that Hibernate ignores the mappedBy values and uses names with prepended "_identifierMapper". After changing the annotations to: {code}@Entity public class SimpleEntity { @Id private int id; @OneToOne(cascade = CascadeType.ALL, mappedBy = "_identifierMapper.entityA") private EntityConnection connection; @OneToMany(cascade = CascadeType.ALL, mappedBy = "_identifierMapper.entityB") private List<EntityConnection> otherConnections; // accessors }{/code} the code works. Expected: the first example of SimpleEntity should work. -- This message is automatically generated by JIRA. For more information on JIRA, see: http://www.atlassian.com/software/jira