Burton Rhodes

This is driving me nuts - can someone tell me why this only inserts an entry in the "join table" when saving a new (persisting), but will not perform an insert when merging an existing object? Please help!

My mapping is as follows:
Contact.java (Excerpt)

@ManyToMany(targetEntity=AppUser.class,cascade={CascadeType.ALL}) @JoinTable(name="ContactOwner", joinColumns=@JoinColumn(name="ContactId"), inverseJoinColumns=@JoinColumn(name="AppUserIdOwner")) private Collection<AppUser> appUsers; public Collection<AppUser> getAppUsers() { return appUsers; } public void setAppUsers(Collection<AppUser> appUsers) { this.appUsers = appUsers; } public void addAppUser(AppUser appUser) { if (!getAppUsers().contains(appUser)) { getAppUsers().add(appUser); } }

And my test code is below:

@Test public void testConAppUser() { EntityManager em = helper.getEm(); em.getTransaction().begin(); // Get two AppUsers to add to the many-to-many collection of Contact AppUser appUser1 = appUserDao.findById(1); AppUser appUser2 = appUserDao.findById(6); // Create new Contact and add the 2 AppUsers Contact contact = new Contact(); contact.setFirstName("John"); contact.addAppUser(appUser1); contact.addAppUser(appUser2); em.persist(contact); em.flush(); // Inserts 2 records into the join_table - perfect! // Get an existing Contact and do the same thing Contact contact2 = contactDao.findById(1, 1); contact2.addAppUser(appUser1); contact2.addAppUser(appUser2); em.merge(contact2); em.flush(); // Oops, no update to the join table at all, WTF?! em.getTransaction().commit(); }

I am struggling with the same problem/requirement. Did you find a solution to this?!?