empty DB joincolumn after cascade insert in bidirectional relationship

Question

I have 2 classes that are connected by a bidirectional ManyToOne / OneToMany relationship:

Member in ClassA:

@OneToMany(cascade = CascadeType.ALL, orphanRemoval = true, mappedBy = "classA")
private List<ClassB> classBList = new ArrayList<ClassB>();

Member in ClassB:

@ManyToOne
@JoinColumn(name = "CLASSA_ID", referencedColumnName = "id")
private ClassA classA;

When I call classA.getClassBList().add(newClassB); a new DB entry for classB is created, but the DB column CLASSA_ID remains null. of course all entities are defined in persistence.xml.

i appreciate any help, maybe it's just a little detail.

---

Thanks to bigGuy My class looks like that now:

@OneToMany(cascade = CascadeType.ALL, orphanRemoval = true)
@JoinColumn(name = "CLASSA_ID", referencedColumnName = "id")
private List<ClassB> classBList = new ArrayList<ClassB>();


@ManyToOne
private ClassA classA

Answer 1

The annotation @JoinColumn indicates that this entity is the owner of the relationship.

In your case, owner is ClassB.

So, you should use this line to create relationship:

newClassB.setClassA(classA);

If you want to create relationships with line

classA.getClassBList().add(newClassB);

make ClassA owner of relationship (move @JoinColumn to classA).