Hibernate throws MultipleBagFetchException – cannot simultaneously fetch multiple bags

I think a newer version of hibernate (supporting JPA 2.0) should handle this. But otherwise you can work it around by annotating the collection fields with:

@LazyCollection(LazyCollectionOption.FALSE)

Remember to remove the fetchType attribute from the @*ToMany annotation.

But note that in most cases a Set<Child> is more appropriate than List<Child>, so unless you really need a List – go for Set

But remind that with using sets you won’t eliminate the underlaying Cartesian Product as described by Vlad Mihalcea in his answer!

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