Cannot delete entity (JPA & Spring) - spring

Question

What ever I try, I cannot delete a user entity when I call delete() from my userService class. I get an exception java.lang.IllegalArgumentException: Entity must be managed to call remove: com.blackbox.genesis.entities.User#30168a, try merging the detached and try the remove again. I'm obviously doing something wrong - despite merging, but I can't see what. Everything else works fine - I can create and update user entities without any problem.
Regards
My entity class;
#Entity
#Table(uniqueConstraints = {#UniqueConstraint(columnNames = "EMAIL")})
public class User implements Serializable {
#Id
#Column(name="username", length=50)
private String username;
#OneToOne(cascade = {CascadeType.ALL})
private Password password;
private boolean enabled;
private int serial;
private String email;
#Version
private int version;
#ElementCollection(targetClass=Authority.class)
#CollectionTable(name="USER_AUTHORITY")
private List<Authority> authorities;
#OneToMany(mappedBy="user", fetch=FetchType.LAZY, cascade=CascadeType.ALL, ``orphanRemoval=true)
private Set<License> licenses;
private static final long serialVersionUID = 1L;
public User() {
super();
this.authorities = new ArrayList<Authority>();
}
.... getters/setters.
My DAO class;
#Repository
public class UserJpaController {
#PersistenceContext
EntityManager em;
protected static final Logger logger = Logger.getLogger("com.blackbox.genesisng.entities.UsersJpaController");
public void create(User user) throws PreexistingEntityException, Exception {
if (findUser(user.getUsername()) != null) {
throw new PreexistingEntityException("Users " + user + " already exists.");
}
em.persist(user);
em.flush();
}
public void edit(User user) throws NonexistentEntityException, Exception {
user = em.merge(user);
em.flush();
}
public void destroy(String id) throws NonexistentEntityException {
User user = em.find(User.class, id);
user = em.merge(user);
em.remove(user);
}
public List<User> findUserEntities() {
return findUserEntities(true, -1, -1);
}
public List<User> findUserEntities(int maxResults, int firstResult) {
return findUserEntities(false, maxResults, firstResult);
}
private List<User> findUserEntities(boolean all, int maxResults, int firstResult) {
Query q = em.createQuery("select object(o) from User as o");
if (!all) {
q.setMaxResults(maxResults);
q.setFirstResult(firstResult);
}
return q.getResultList();
}
public User findUser(String id) {
return em.find(User.class, id);
}
public int getUserCount() {
Query q = em.createQuery("select count(o) from User as o");
return ((Long) q.getSingleResult()).intValue();
}
public User findUserByEmail(String email) {
Query q = em.createQuery("select Object(o) from User as o where o.email = :email");
q.setParameter("email", email);
List list = q.getResultList();
if (list.size() == 0) {
return null;
}
return (User) list.get(0);
}
public boolean exists(String id) {
try {
em.getReference(User.class,id);
return true;
}
catch (EntityNotFoundException e) {
return false;
}
}
}
and finally, the relevant portion of my service class
#Service
public class UserService {
#Autowired
UserJpaController dao;
#Autowired
LicenseJpaController licenseDao;
#Transactional
public void delete(UserDTO userDTO) {
if (exists(userDTO.getUserName())){
try {
dao.destroy(userDTO.getUserName());
} catch (NonexistentEntityException e) {
// ignore as the previous test should prevent this.
}
}
}

Answer 1

So sorry, but I'm an idiot! I was not calling the service class that I thought I was. Fixed that and everything works as expected. Once again, sorry folks.
Regards

Answer 2

Remove the
user = em.merge(user);
statement in your DAO destroy method. I am not sure if it causes the probem, but it is not needed because the user is loaded in the statement before.