1-Implement A generic LinkedList class, which implements List interface That has the following . Get data stored in head node of list. public T getFirst : / Get the head node of the list / public ListNodegetFirstNode Get data stored in tail node of list.-/ public T getLast Insert a new node with data at the head of the list / public void insertFirst (T data); Insert a new node with data after currentNode public void insertAfter ListNode currentNode, T data); Insert a new node with data at the tail of the list. public void insertlast (T data - Remove head node public void delete First : - Remove tail node public void delete Last (: Remove node following currentNode If no node exists (le, currentNode is the tail), do nothing / public vold deleteNext ListNode currentNode); Get the number of elements in this list public int size : / . Check if the list is empty. public boolean isEmpty : / **You need to write the implementation for each function Then implement A Junit test class LinkedListTester, which should test all the functions you imple- mented in your LinkedList class