2) Suppose you have a linked list class that provides the following methods: LinkList() // constructor. int size(); // returns size of the list. void insertHead(object data) // insert new data at the head of // the list. Object removeHead() // remove and return the object at // the head of the list. void insertTail (Object data) // insert new data at the tail of // the list. The class below is an implementation of a Stack using the linked list class. Fill in the method implementations: class Stack { private Stack S; public Stack() 1 public void push(Object x) { 1 public Object pop() // assume stack is not empty { } public boolean isEmpty() }