Hibernate, get child object from abstract parent

Question

I am getting a parent abstract object from hibernate. What is the best way to get true child object?

I think this is not a correct way to do it:

Long parentId=parent.getId();
Child child=childMgr.getInstance().getById(parentId);

Answer 1

Your Child should be already declared in your Parent object class:

public class parent{
    private Child child ;
//setter getter
}

then in your parent hbm (varies if using annotation) you map it:

<one-to-one cascade="none" name="child" not-null="true"
        class="com.example.child" 
        column="FOREIGN_KEY" />

Then once you have the parent you can just call:

Child child = parent.getChild();

This only applies if you have one to one relationship, varies for one to many, will need to set as list.