Collections - The Java Programming Language - page 843

21.2. Iteration
You've encountered iteration several times already during the course of
this topic particularly in the discussion of the enhanced for loop in Chapter
10 . This section reviews the basic operation of an iterator and covers its
additional capabilities and the additional iterator types.
Collection<E> extends Iterable<E> , which defines an iterator method that
returns an object that implements the Iterator<E> interface:
public boolean hasNext()
Returns true if the iteration has more elements.
public E next()
Returns the next element in the iteration. If there is no next
element a NoSuchElementException is thrown.
public void remove()
Removes the element returned most recently by the iteration
from the underlying collection. remove can be called only once
per call of next . If next has not yet been called, or if remove
has already been called since the last call to next , an Illeg-
alStateException is thrown. (Optional)
The following code uses all three methods of Iterator to remove all long
strings from a collection:
public void removeLongStrings
(Collection<? extends String> coll, int maxLen) {
Iterator<? extends String> it = coll.iterator();
while (it.hasNext()) {
String str = it.next();
if (str.length() > maxLen)