I learn generic for the first time and I just get into wilcards.
there is two declaration of method in the collection interface :
1. boolean add(E e) // add the element e
2. boolean removeAll(Collection<?> c) // remove the elements in c
why the first one get a E param and in the second mehod is ? param
I understand that when you use the ? mark you are saying that all the elements in the collection are from the same type but I think it was the same if you write in the second method : Collection<E> c.
what am I missing?