simple LL java

import java.io.*;
import java.util.Scanner;

class ListElement{

    public int data;
    public ListElement link;
    public ListElement list1,list2;

    Scanner sc = new Scanner(System.in);
    //construtor
    ListElement(int data){
        this.data = data;
        this.link = null;
    }

    //method to update data in List element
    void updatedata(int data){
        this.data = data;
    }

    //method to setup the Link
    void setLink(ListElement node){
        this.link = node;
    }

    int getdata(){
        return this.data;
    }

    ListElement getNextNode(){
        return this.link;
    }

    ListElement insert(ListElement head,ListElement node,int position){

        ListElement previousNode = new ListElement(head.data);
        previousNode.setLink(head.link);

        if(head == null){
            return node;
        }
        else{
            int size = length();
            if(position > size+1){
                System.out.println("Invalid position.");
                System.out.println("Valid positions are from 0 to " + size);
                return head;
            }
            if(position == 1){
                node.setLink(head);
                return node;
            }
            else if(position == 2){
                ListElement temp = new ListElement(-11);
                temp.setLink(head.link);
                head.setLink(node);
                node.setLink(temp.getNextNode());
            }
            else{
                int pos = 1;
                while(pos != position-1){
                    previousNode = previousNode.getNextNode();
                    pos++;
                }
                //ListElement temp = head.getNextNode();

                previousNode.setLink(node);
                node.setLink(null);
            }
        }
        return head;
    }

    ListElement insertAtEnd(ListElement node){
        ListElement head = this;
        int size = head.length();

        ListElement temp = this;
        while(temp.link!=null){
            temp = temp.getNextNode();
        }
        temp.setLink(node);
        return head;
    }

    void display(ListElement head){
        ListElement node = head;
        int position = 1;
        while(node!= null){
            System.out.println("Position " + position + " = " + node.data);
            position++;
            node = node.getNextNode();
        }
    }

    ListElement makeDummyList() {
        ListElement head = this;
        for(int i=2 ; i < 10 ; i++){
            ListElement node = new ListElement(i);
            head.insert(head,node,i);
        }
        return head;
    }

}
public class LinkedList {



    public static void main(String args[]){
        Scanner sc = new Scanner(System.in);
        ListElement head = new ListElement(1);
        head.setLink(null);
        int cont =1;
        head = head.makeDummyList();
        while(cont == 1){
            System.out.println("Program to implement linked list");
            System.out.println("The Following choices are availiable : ");
            System.out.println("1.Insert element in Linked List");
            System.out.println("2.Delete element from Linked List");
            System.out.println("3.Display Linked List");

            System.out.println("0.Exit");
            System.out.print("Enter Your choice :");

            int choice = sc.nextInt();

            switch(choice){

                case 1:
                    System.out.print("Enter data : ");
                    int data = sc.nextInt();
                    System.out.print("Enter position : ");
                    int position = sc.nextInt();

                    ListElement node = new ListElement(data);
                    if(head == null){
                        head = node;
                    }
                    else{
                        int length = head.length();
                        head = head.insert(head,node,position);
                    }
                    break;

                case 2:
                    System.out.println("There are two choices :");
                    System.out.println("1.Delete by data");
                    System.out.println("2.Delete by position");
                    System.out.print("Enter Your choice :");
                    int choices = sc.nextInt();
                    switch (choices){
                        case 1:
                            System.out.print("Enter the data to be deleted : ");
                            int deleteData = sc.nextInt();
                            head = head.deleteByData(head,deleteData);
                            break;

                        case 2:
                            System.out.print("Enter position of element to be deleted : ");
                            int pos = sc.nextInt();
                            head = head.deleteByPosition(head, pos);
                            break;
                    }
                    break;

                case 3:
                    head.display(head);
                    break;

                case 0:
                        cont = 0;
                        break;

            }
        }
    }

}