Assign a subclass of a Generic class to a super class of this class

Question

I have couple of supplied interfaces

public interface Finder,T extends Item> {
    public S find(S s, int a);
}

public interf         


        

Answer 1

Your type S is a subtype of Stack but the copy method is upcasting it to a Stack that may be any subtype of Stack. You will have to cast the result of copy to S