Singly Linked List in Java

// Linked in Java Program
import java.lang.*;

class LinkedList {
    Node head;
    // not using parameterized constructor would by default
    // force head instance to become null
    // Node head = null;  // can also do this, but not required

    // Node Class
    class Node {
        int data;
        Node next;

        Node(int x) // parameterized constructor
        {
            data = x;
            next = null;
        }
    }

    public Node insertNode(int data) {
        // Using constructor to create memory and value assignment
        Node new_node = new Node(data);
        // current head becomes this new_node's next
        new_node.next = head;

        // changing head to this newly created node
        head = new_node;

        return head;
    }

    public void delete()
    {
        if (head == null){
            System.out.println("List is empty, not possible to delete");
            return;
        }

        System.out.println("Deleted: " + head.data);
        // move head to next node
        head = head.next;
    }



    public void display()
    {
        Node node = head;
        //as linked list will end when Node reaches Null
        while(node!=null)
        {
            System.out.print(node.data + " , ");
            node = node.next;
        }
        System.out.println();
    }

}
class Main{

    public static void main(String args[])
    {
        LinkedList listObj = new LinkedList();

        listObj.insertNode(25);
        listObj.insertNode(20);
        listObj.insertNode(15);
        listObj.insertNode(10);
        listObj.insertNode(5);

        listObj.display();

        listObj.delete();
        listObj.delete();
        listObj.delete();

        listObj.display();

    }
}