Iterator: One past the last element in Java

Question

Like in C++, we have end() where the iterator ends up at the position one past the last element, is it true for Java iterator has well?

while (iterator.hasNext()) {
    String color = iterator.next();
}

E.g. In C++, we have:

Blue Green Purple
  ^    ^     ^    ^
begin            end

How would I have to draw the above illustration in Java thinking/terminology?

Answer 1

In Java, Iterator is an interface meaning that there has to be a concrete class implementing the methods of the interface. Now that depends on the type of collection that is used. As an example, to iterate on a collection of the type List, we use a ListIterator.

For a listIterator, there is no current element that it holds. The cursor position would lie between elements, at the beginning of the collection or at the end of the last element in the list. The illustration should make it more clear.

So, when hasNext() returns false, you know you are at the end of the Collection (List, in our case) which throws a NoSuchElementException.