Create an AVL Tree Map in java (AVLTreeMap.java). That is, create a map which depends on the self-balancing AVLTree. Below are five functions which need to be implemented into the program. The map interface (AVLTreeMap should implement Map.java) and Node class are also given. \\Map.java Interface 

public interface Map { public int size(); public void put(String key, String value); public String get(String key); } 

\\AVLTreeMap.java

public class AVLTreeMap implements Map { 

class Node { String k; String val; int height; Node parent;  Node left; Node right; public Node(String key, String value) { this.k = key; this.val = value; this.height = 1; this.parent = null; this.left = null; this.right = null; } public int balance() { // FIXME  return -1; } } 

public AVLTreeMap() { // FIXME } public int size() { // FIXME  return -1; } public void put(String key, String value) { // FIXME } public String get(String key) { // FIXME  return null; }