Java program to insert a new node at the end of the singly linked list

public class InsertEnd {  
  
    //Represent a node of the singly linked list  
    class Node{  
        int data;  
        Node next;  
  
        public Node(int data) {  
            this.data = data;  
            this.next = null;  
        }  
    }  
  
    //Represent the head and tail of the singly linked list  
    public Node head = null;  
    public Node tail = null;  
  
    //addAtEnd() will add a new node to the end of the list  
    public void addAtEnd(int data) {  
        //Create a new node  
        Node newNode = new Node(data);  
  
        //Checks if the list is empty  
        if(head == null) {  
            //If list is empty, both head and tail will point to new node  
            head = newNode;  
            tail = newNode;  
        }  
        else {  
            //newNode will be added after tail such that tail's next will point to newNode  
            tail.next = newNode;  
            //newNode will become new tail of the list  
            tail = newNode;  
        }  
    }  
  
    //display() will display all the nodes present in the list  
    public void display() {  
        //Node current will point to head  
        Node current = head;  
        if(head == null) {  
            System.out.println("List is empty");  
            return;  
        }  
        System.out.println("Adding nodes to the end of the list: ");  
        while(current != null) {  
            //Prints each node by incrementing pointer  
            System.out.print(current.data + " ");  
            current = current.next;  
        }  
        System.out.println();  
    }  
  
    public static void main(String[] args) {  
  
        InsertEnd sList = new InsertEnd();  
  
        //Adding 1 to the list  
        sList.addAtEnd(1);  
        sList.display();  
  
        //Adding 2 to the list  
        sList.addAtEnd(2);  
        sList.display();  
  
        //Adding 3 to the list  
        sList.addAtEnd(3);  
        sList.display();  
  
        //Adding 4 to the list  
        sList.addAtEnd(4);  
        sList.display();  
    }  
}  

Output:

Adding nodes to the end of the list: 
1 
Adding nodes to the end of the list: 
1 2 
Adding nodes to the end of the list: 
1 2 3 
Adding nodes to the end of the list: 
1 2 3 4