Showing posts from July, 2010

Hibernate Exception - Simultaneously Fetch Multiple Bags

Hibernate Exception - Simultaneously Fetch Multiple Bags One of my customers has just upgraded to JBoss 4.0.4-GA, the process also required us to upgrade Hibernate products to the following versions: Hibernate core – 3.2.0CR2 Hibernate Entity Manager – 3.2.0CR1 Hibernate annotations- 3.2.0CR1 We fixed some minor changes and improvements and then we bumped into the following exception  javax.persistence.PersistenceException: org.hibernate.HibernateException: cannot simultaneously fetch multiple bags at org.hibernate.ejb.Ejb3Configuration.createEntityManagerFactory( at org.hibernate.ejb.HibernatePersistence.createEntityManagerFactory( So what is the problem? When an entity has more than one non-lazy association that might be interpreted as a bag (e.g., java.util.List or java.util.Collection properties annotated with @org.hibernate.annotations.CollectionOfElements or @OneToMany or @ManyToMany and not anno