Hibernate Bi-Directional ManyToMany Updates with Second Level cache

Question

I have a bidirectional many-to-many class:

public class A{
 @ManyToMany(mappedBy="listA")
 private List<B> listB;
}
public class B{
 @ManyToMany
 private List<A> listA;
}

Now I save a listA into B:

b.setListA(listA);

This all works fine until I turn on second-level caching on the collection a.ListB. Now, when I update the list in B, a.listB does not get updated and remains stale.

How do you get around this?

Thanks, Dwayne

Answer 1

Are you setting both sides of your bidirectional link between A and B correctly? A typically approach is to use defensive methods like this:

public class B {
    @ManyToMany
    private List<A> listA;

    public void addToListA(A a) {
        this.listA.add(a);
        a.getListB().add(this);
    }

    public void removeFromListA(A a) {
        this.listA.remove(a);
        a.getListB().remove(this);
    }
}