Retrieves, but does not remove, the last element of this deque.
This method differs from {@link #peekLast peekLast} only in that it
throws an exception if this deque is empty.
@return the tail of this deque
@throws NoSuchElementException if this deque is empty
Retrieves, but does not remove, the last element of this deque. This method differs from {@link #peekLast peekLast} only in that it throws an exception if this deque is empty.
@return the tail of this deque @throws NoSuchElementException if this deque is empty