JPA OneToMany - Collection is null

Question

I\'m trying to set up a bidirectional relationship using JPA. I understand that it\'s the responsability of the application to maintain both sides of the relationship.

Answer 1

Try to set the fetch type association property to eager on the OneToMany side. Indeed, you may leave this part (this.library.getBooks().add(this)) to be written within a session:

Library l = new Library();    
Book b = new Book();
b.setLibrary(l);
l.getBooks().add(b);