Saving bidirectional ManyToMany

Question

I have two entity classes annotated in the following way

@Entity
class A {
   @ManyToMany(mappedBy=\"A\", cascade=CascadeType.ALL)
   private List b         


        

Answer 1

Have you specified the inverse join columns?

@Entity
class A {
   @ManyToMany(mappedBy="A", cascade=CascadeType.ALL)
   private List  b;
   ..
}

@Entity 
class B { 
   @ManyToMany 
   @JoinTable (
       name="A_B",
       joinColumns = {@JoinColumn(name="A_ID")},
       inverseJoinColumns = {@JoinColumn(name="B_ID")}
   )
   private List a; 
   .. 
} 

That's assuming a join table called A_B with columns A_ID and B_ID.