All the classes released in Java 2 that implement the collection interface contain an iterator () method, which returns an instance of the Iterator. There's nearly universal support for the Iterator ...

When no more objects passing the filtering Iterator’s test are available, the next method throws a NoSuchElementException in accordance with the java.util.Iterator interface requirements.

The java.util.SortedSet is a specialization of the Set interface. It represents a set where the elements are sorted. The Set interface does not impose any particular order on its elements.