You should create a class called yoursimplelinkedlist that inherits from simplelinkedlist and provide a correct implementation of getitem. getitem should return a reference to the item at that position in the list, or null if no such item exists. you may want to look at the implementation of size in simplelinkedlist for a reminder of how to walk a linked list using a for loop. you will also need to provide a constructor for yoursimplelinkedlist that takes an array of object references and simply passes them to a call to super to properly initialize simplelinkedlist.