1. Write a program, that enqueues/dequeues some test strings, modifies the head and displays the state of the queue between these different operations to demonstate how the queue is affected in Java.

2. Implement push, pop and isEmpty methods based on a DoublyLinkedList below in Java.

public class MyStack implements IStack { //INCOMPLETE public void push(E val) { //TODO: implement pushing } //INCOMPLETE public E pop() { //TODO: implement popping return null; } //INCOMPLETE public boolean isEmpty() { //TODO: check whether list is empty return false; } } } public class MyStack implements IStack { //INCOMPLETE public void push(E val) { //TODO: implement pushing } //INCOMPLETE public E pop() { //TODO: implement popping return null; } //INCOMPLETE public boolean isEmpty() { //TODO: check whether list is empty return false; } } }