**Use the Stack interface to implement the LinkedStack.java class.

Stack.java

public interface Stack { /** * Push an element onto the stack. * * @param element, a value to be pushed on the stack */ public void push(E element); /** * Pop the top element off the stack. */ public E pop(); /** * Return the top element on the stack. */ public E top(); /** * Return True if the stack contains no elements. * * @return true if there are no elements in the stack */ public boolean isEmpty(); }

***In LinkedStack.java, change only The methods with empty bodies Do not use a sentinel node. In this implementation you use an inner class That is, a class that is declared inside of another class. The Node class isn't needed by any other class, so it is declared as a private class inside the LinkedStack class. The Node class has two fields: element and next. Things to note in the class LinkedStack: The EmptyStackExceptionis being used, same as in the ArrayStack. The class StringJoineris imported for use in the toString()

LinkedStack.java

import java.util.EmptyStackException; import java.util.StringJoiner; public class LinkedStack implements Stack { private class Node { public E element; public Node next; public Node(E element) { this(element, null); } public Node(E element, Node next) { this.element = element; this.next = next; } } private Node top; /** * Constructor for objects of class LinkedStack */ public LinkedStack() { } @Override public void push(E element) { // Complete this method } @Override public E pop() { // Complete this method } @Override public E top() { // Complete this method } @Override public boolean isEmpty() { // Complete this method } @Override public int size() { // Complete this method }

@Override public String toString() { StringJoiner joiner = new StringJoiner(", ", "[", "]"); for (Node current = top; current != null; current = current.next) { joiner.add(current.element.toString()); } return joiner.toString(); }