Program 14_01:Modify the class LinkedListin Exercise 13_01 to make it a doubly linked list:-Name your class DoublyLinkedListand create a tester class Main.-Use dummy header and trailer nodes.-Add a printInReversemethod.-Add an appendmethod to add an item at the end of the list.

public class LinkedList implements ListInterface {

public class Node {

private int info; private Node next;

public Node() { info = 0; next = null; }

public void setInfo(int i) { info = i; }

public void setNext(Node l) { next = l; }

public int getInfo() { return info; }

public Node getNext() { return next; } }

private Node first;

public LinkedList() { first = new Node(); }

public boolean isEmpty() { return (first.getNext() == null); }

public void display() { Node current = first.getNext();

while (current != null) { System.out.print(current.getInfo() + " "); current = current.getNext(); }

System.out.println(); }

public boolean search(int x) { Node current = first.getNext();

while (current != null) { if (current.getInfo() == x) { return true; } current = current.getNext(); }

return false; }

public void add(int x) { Node p = new Node();

p.setInfo(x); p.setNext(first.getNext());

first.setNext(p); }

public void remove(int x) { Node old = first.getNext(), p = first;

boolean found = false; while (old != null && !found) { if (old.getInfo() == x) { found = true; } else { p = old; old = p.getNext(); } }

if (found) { p.setNext(old.getNext()); } }

public void insert(int x, int loc) {

}

public void removeItemAt(int loc) {

} }

//Interface

public interface ListInterface {

public boolean isEmpty();

public void display();

public boolean search(int x);

public void add(int x);

public void remove(int x);

public void insert(int x, int loc);

public void removeItemAt(int loc); }