Question

public class Application{
   @Id
   private Long id;

   @OneToMany(mappedBy = "application")
   private List<Licence> licences = new ArrayList<Licence>();
   ...
}

public class Licence{
   @Id
   private Long id;

   @ManyToOne(fetch = FetchType.LAZY)
   @JoinColumn(name = "ID", nullable = false)
   private Application application;
   ...
}

How do I get hibernate to leave licences in application object readonly and not try to persist Licence when I go em.merge(application);

I’m not trying to save Licence with Cascade in Application. Licences have a lot business rules to run before they actually get persisted so I will be calling persist on each licence individually. How do I do this ? This works fine on persist but not on merge.

On merge I keep getting

org.hibernate.TransientObjectException: object is an unsaved transient 
     instance - save the transient instance before merging: com.cmr.Licence

Answer 1

Use insertable = false, updatable = false. Update this

  @ManyToOne(fetch = FetchType.LAZY)
  @JoinColumn(name = "ID", nullable = false)
  private Application application;

to

  @ManyToOne(fetch = FetchType.LAZY)
  @JoinColumn(name = "ID", nullable = false, insertable = false, updatable = false)
  private Application application;