I I have problem to come up with the last part Boolean in OrderedList.java class

Computer Staff Logon Welcome 3352 Robbinsville Police Non-Emergency 609 2593900 US Security Lawrenceville Office: 609.396 9500 Mon ay Tue Robson mccc/cos210/ds/OrderedList.java - Eclipse IDE earch Project Run Window Help "OrderedListjavaOrderedlist java DoublylLinked ist java DStack java 1 package edu.mccc.cos218.ds; 3 public crass OrderedList extends DoublyLinkedListo implements lorderedustob f 4 Override 5 public void add(T data) ( addFirst(data); addLast (data); 1e 12 13 Override 14 public boolean contains (T data) f 15 16 17 18 boolean tail false; java.util.Iterator it iterator); while (it.hasNext)) ( return head !- null; 20 21 23 @ Console 3 No consoles to display at this time. 0 errors, 2 warnings 4 Descriptiorn s Warnings (2 ite i Infos (4 items) Writable Smart Insert TOURS 2-10 Mon Tue Wed Jay Robson Jay Computer Staff Logon Welcome 335t Robbinsville Police Non-Emergency 609 259 3900 US Security Lawrenceville Office: 609.396 9500 Allied Universal Melissa Hammond 561.440 0215 /cos210/ds/1OrderedList.java-Eclipse IDE Project Run Window Help .OrderedListjava IOrderedistjava 1T DoublyLinkedList java D stackjava backage ed mC.cos 3 public irntterface IOrderedListcT extends IDoublyLinkedListeT>, java. lang.IterablecT> f public void add(T data); 5 public boolean contains(T data) Console o consoles to display at this time = Problems 0 errors, 2 warnings, 4 others Description Warnings (2 items) Infos(4iterns) OrderedList.java lOrderedList.ja ds List.java va y.java ist.java .ds List.java va