Builder pattern for polymorphic object hierarchy: possible with Java?

Question

I have a hierarchy of interfaces, with Child implementing Parent. I would like to work with immutable objects, so I would like to design Bui

Answer 1

Use generics, as follows:

public interface Parent {
    public Long getParentProperty();
}

public interface Child {
    public T getChildProperty(); 
}

Then instead of Child1, use Child and instead of Child2, use Child.