Hi all,

I know that one has to use Set or annotations when a JPA entity has two or more collections or @OneToMany relationships to get the collections to populate on eager loading. However I am getting this error on one of my entities that has two @ManyToOne relationships. It has worked without problems for hundreds of other entity classes that I have created in the past. The only difference is that this time I am using a pre-existing data base so need to map the objects to the names they have in the database, ie the database naming convention is different to the default for hibernate.

I have setup my class as follows:


@ManyToOne
@JoinColumn(name="analysisgid")
private AnalysisGroup analysisGroup;

@ManyToOne
@JoinColumn(name="customerid")
private Organisation customer;

When running my unit tests I get the "simultaneous bag" error.


Caused by: org.hibernate.HibernateException: cannot simultaneously fetch multiple bags
at org.hibernate.loader.BasicLoader.postInstantiate(BasicLoader.java:66)
at org.hibernate.loader.entity.EntityLoader.<init>(EntityLoader.java:75)
at org.hibernate.loader.entity.EntityLoader.<init>(EntityLoader.java:43)
at org.hibernate.loader.entity.EntityLoader.<init>(EntityLoader.java:33)
at org.hibernate.loader.entity.BatchingEntityLoader.createBatchingEntityLoader(BatchingEntityLoader.java:103)
at org.hibernate.persister.entity.AbstractEntityPersister.createEntityLoader(AbstractEntityPersister.java:1752)
at org.hibernate.persister.entity.AbstractEntityPersister.createEntityLoader(AbstractEntityPersister.java:1756)
at org.hibernate.persister.entity.AbstractEntityPersister.createLoaders(AbstractEntityPersister.java:2989)
at org.hibernate.persister.entity.AbstractEntityPersister.postInstantiate(AbstractEntityPersister.java:2982)
at org.hibernate.persister.entity.SingleTableEntityPersister.postInstantiate(SingleTableEntityPersister.java:690)
at org.hibernate.impl.SessionFactoryImpl.<init>(SessionFactoryImpl.java:290)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1300)
at org.hibernate.cfg.AnnotationConfiguration.buildSessionFactory(AnnotationConfiguration.java:859)
at org.hibernate.ejb.Ejb3Configuration.buildEntityManagerFactory(Ejb3Configuration.java:669)

Could it be that the error relates to another class? The error goes away if I take either one of the @ManyToOne mappings above out of the entity bean.

thanks