Can I add to a generic collection of type A values of type B ,which extends A, without any special syntax?

Question

public class Stack {
    public Stack () {....}
    public void push (E e) {....}
    public E pop () {....}
    public boolean isEmpty(){....}
}

public void p         


        

Answer 1

the problem is that you have two types but only one generic representation (E) so E is Number as well as Integer. Thats confusing him. You need to have the same type for the collection. Rewrite it to

pushAll(Collection src) 

and cast K to E.