OneToMany ManyToOne使用Hibernate删除子对象

Question

I'm using Spring Boot and Hibernate. Lets assume we have two entities:

@Entity
public class A{
    @OneToMany(mappedBy = "objectA",fetch = FetchType.EAGER,cascade = CascadeType.ALL,orphanRemoval=true)
    private Set<B> objectSet = new HashSet<>();
}
@Entity
public class B{
    @ManyToOne
    private A objectA;
}

And we have two transacional methods;

deleteB_X(int idB){
    entityManager.remove(entityManager.find(idB,B.class));
}
deleteB_Y(int idB){
    B obj=entityManager.find(idB,B.class);
    obj.getObjectA().getObjectSet().remove(obj);
}

What I understand (correct me if I'm wrong):

1. We have orphanRemoval=true so deleteB_Y(int) will work.
2. By setting mappedBy argument we say that class A is "the owning site" of relation.
3. CascadeType is used when we persist/update/merge/remove class A (then it invokes persist/update/merge/remove on child property objectSet ). I think we can say that it protects me from situation where I end up with object of B and no object of A class (unless we manually add some B objs).

From what I understand CascadeType should not interfare with orphanRemoval, because CascadeType takes care of things where we do 'some stuff' with A's objects (and then recursively do it to B's objects). And here is something that I don't understand at all. Why deleteB_x(int) doesn't work and why if we remove CascadeType it starts working? I feel like that deleteB_X(int) is much cleaner solution to removing object B from the DB than deleteB_Y(int) , but sadly it won't work since it colides with CascadeType.

EDIT1. Method deleteB_X(int) just doesn't remove object from DB, if we remove cascade = CascadeType.ALL evertyhing works just fine. Why?

Answer 1

The issue was that my class A was fetched EAGER in class B instance and because of that (I assume) that there was a conflict when I was deleting B 's instance alone without taking care of the same B instance in private Set<B> objectSet . Changing EAGER to LAZY or excluding CascadeType.PERSIST from @OneToMany(cascade=...) solved my issue.