// Textbook fragment 06.02
  /** Returns the number of elements in this list. */
  public int size();
  /** Returns whether the list is empty. */
  public boolean isEmpty();
  /** Inserts an element e to be at index i, shifting all elements after this. *
/
  public void add(int i, E e)
    throws IndexOutOfBoundsException;
  /** Returns the element at index i, without removing it. */
  public E get(int i)
    throws IndexOutOfBoundsException;
  /** Removes and returns the element at index i, shifting the elements after th
is. */
  public E remove(int i)
    throws IndexOutOfBoundsException;
  /** Replaces the element at index i with e, returning the previous element at
i. */
  public E set(int i, E e)
    throws IndexOutOfBoundsException;