How to trigger Entity's callback method?

Question

In my project(JPA2.0,EclipseLink,mysql),I have a entity listener. For example,When entity updated, the method with annotation '@postupdate' will be triggered. This works well.
But sometimes,user updated the entity(getEntityManager().merge), JPA provider will check whether entity's property changed. If there is no change in entity, JPA provider will not update this entity.(This is cache mechanism,I think). So the the method marked '@postupdate' will not be triggered. But I need the '@postupdate' method triggered at this situation. How to do it?

Answer 1

Just thought of something else you can try (if it's that important):public class A {
    public String toString () {
        return "A";
public class B extends A {
    public String toString () {
        return "B (A: " + super.toString () + ")";
}Kind regards,
  Levi