import java.util.*;
public class ArrayDeque_Iterator_1 {
public static void main(String[] args) throws Exception {
ArrayDeque<Integer> q = new ArrayDeque<Integer>();
q.add(1);
q.add(2);
Iterator i = q.iterator();
i.hasNext();
q.add(3);
// The iterator is not valid anymore because the deque has been modified above.
i.next();
}
}