UnsupportedOperationException merge-saving many-to-many relation with hibernate and JPA

Question

I\'ve set up a simple many-to-many relationship account : role with Hibernate but when I try to save an account in a unit test after it has had its role added I get an Unsup

Answer 1

Hibernate's persistent variant of the Collection in question attempts to delegate to an abstract base class (PersistenceBag) that doesn't implement the add method.