JPA2. 0: delete entity in onetomany relationship

How to delete an entity in a onetomany relationship

@Entity
@NamedQueries({
   @NamedQuery(name="User.findByUserNamePassword",query="select c from User c where c.userName = :userName AND c.password = :password")
})
@Table(name="\"USER\"")
public class User implements Serializable {
    @OneToMany(mappedBy="user",cascade=CascadeType.ALL,orphanRemove=true)
    private List<Profession> professions;

    public List<Profession> getProfessions() {
       return professions;
    }

    public void setProfessions(List<Profession> professions) {
       this.professions = professions;
    }

    public void addProfession(Profession profession){
       if(this.professions == null){
          this.professions = new ArrayList<Profession>();
       }
       this.professions.add(profession);
       profession.setUser(this);
    }

    public void removeProfession(Profession profession){
       if(this.professions != null){
          professions.remove(profession);
          profession.setUser(null);
       }
    }
}

Internal professional entity

@Entity
public class Profession implements Serializable {
    @ManyToOne
    @JoinColumn(name="UserId",nullable=false)
    private User user;

    public User getUser() {
       return user;
    }

    public void setUser(User user) {
       this.user = user;
    }

Then I have this in my EJB

@Stateless
@LocalBean
@TransactionAttribute(TransactionAttributeType.required)
public class ScholarEJB{

    /**
     * Add a profession to a target user
     * @param user
     * @param profession
     */
    public void addProfession(User user,Profession profession){
        //Put the user in a managed state. It is important to do this before
        //adding a new profession onto user
        user = find(User.class,user.getId());
        user.addProfession(profession);
        this.create(user);   //This is persist action
    }

    public void removeProfession(User user,user.getId());
        user.remove(user);
        this.update(user);  //merge action
        //this.create(user) //also try this as well,but it does not work
    }
}

Now addprofessional works beautifully, but removeprofessional doesn't work Do not know why? Please help. Do I need to evict the cache?

Solution

If a profession is only part of this relationship, you can ensure that when a profession is deleted from the user's collection, it will also be deleted from the database by opening orphanremoval on the onetomany side of the relationship

@OneToMany(mappedBy="user",orphanRemoval=true)
private List<Profession> professions;

This is what the JPA 2.0 specification says

The JPA 2.0 specification points this out