Merge operation without exception but with no impact on the database Glassfish 4.1 JPA

Question

I got a table with a string field and try to update this field and the merge the update to the database via EntityManager. This is done and without exceptio but I see no effect on the database and ran out of ideas what's up there. Hope somebody has an idea. In the below exampl match != null and with both print statements I get the expected value written to my log. But the merge within the transaction has no impact on the database even though the commit terminated.

@Named
@SessionScoped
@ManagedBean
public class LoginController implements Serializable {

    @PersistenceUnit
    private EntityManagerFactory emf;

    public String mymethod(){
        ...
        match.setPwdResetId(rs);
        System.out.println("reset it is now "+match.getPwdResetId());
        try{
            ut.begin();
            emf.createEntityManager().merge(match);
            ut.commit();
        }
        catch(Exception e){
            FacesMessage m2 = new FacesMessage("Values could not be saved. ");
            FacesContext.getCurrentInstance().addMessage("ResetForm", m2);
            System.out.println("exceptio persisting "+e);
            return "message.jsf";
        }  
        System.out.println("reset it is now2 "+match.getPwdResetId());

Answer 1

Please detach the entity and try again. You can read more at the jpa 2 specification. I post a sample for the merge operation:

The semantics of the merge operation applied to an entity X are as follows:

• If X is a detached entity, the state of X is copied onto a pre-existing managed entity instance X' of the same identity or a new managed copy X' of X is created.

• If X is a new entity instance, a new managed entity instance X' is created and the state of X is copied into the new managed entity
  instance X'.

• If X is a removed entity instance, an IllegalArgumentException will be thrown by the merge operation (or the transaction commit will
  fail).

• If X is a managed entity, it is ignored by the merge operation, however, the merge operation is cascaded to entities referenced by
  relationships from X if these relationships have been annotated with
  the cascade element value cascade=MERGE or cascade=ALL annotation.

• For all entities Y referenced by relationships from X having the cascade element value cascade=MERGE or cascade=ALL, Y is merged
  recursively as Y'. For all such Y referenced by X, X' is set to
  reference Y'. (Note that if X is managed then X is the same object as X'.)

• If X is an entity merged to X', with a reference to another entity Y, where cascade=MERGE or cascade=ALL is not specified, then
  navigation of the same association from X' yields a reference to a
  managed object Y' with the same persistent identity as Y.

The persistence provider must not merge fields marked LAZY that have not been fetched: it must ignore such fields when merging. Any Version columns used by the entity must be checked by the persistence runtime implementation during the merge operation and/or at flush or commit time. In the absence of Version columns there is no additional version checking done by the persistence provider runtime during the merge operation.

you can find the whole pdf here