Quicklist class

I found this QuickList class to be very useful for passing dynamic parameters to functions without using Vectors and the likes:

/** 
 * Simple class for generating lists.
 *
 * QuickList differs from the List Collection in as much as once created,
 * a QuickList does
 * not change. New elements are added to a QuickList by creating a
 * new QuickList which includes both the new element and the old QuickList.
 *
 * This makes QuickList suitable for generating low-overhead
 * temporary data structures (amongst other things).
 */
public class QuickList {
  
  /**
   * All elements in this QuickList apart from the first 
   */
  private QuickList tail;
  /**
   * The first element in this QuickList
   */
  private Object head;
      
  /**
   * Empty Quicklist. Add to the empty QuickList in order to generate a new list
   */
  public static final QuickList EMPTY = new QuickList(null, null);
  
  /**
   * Creates a new instance of QuickList. 
   *
   * @param tail A list to which a new item is being appended
   * @param head a new item to append to a list
   */
  protected QuickList(QuickList tail, Object head) {
    this.head = head;
    this.tail = tail;
  }
  
  /**
   * Adds an item to a list.
   *
   * Note that this method does not change this list, but instead returns a
   * new list with the new item added to it.
   *
   * @param item An item to add to the list
   * @return A new list with item added to the front
   */
  public QuickList add(Object item) {
    return new QuickList(this, item);
  }
  
  /**
   * Get the first item in this list.
   *
   * @return the first item in this list
   */
  public Object head() {
    return head; 
  }
  
  /**
   * Get the rump of this list (everything except the first item).
   *
   * @return A list including all items except the first
   */
  public QuickList tail() {
      return tail;
  }
     
   /**
    * Calculate the size of a QuickList
    *
    * @return Number of elements in this quicklist (not counting EMPTY element)
    */
  public int size() {
    if (this == EMPTY)  return 0;
    else                return tail.size() + 1;
  }
}

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