Program for implement array for insert or delete ele in java

import java.io.*;
class arr
    {
        public static void main(String args[])throws IOException
            {
                BufferedReader br=new BufferedReader(
                    new InputStreamReader(System.in));
                int ar[]=new int[100];
                int n,i,j,pos,ch;
                System.out.print("Enter number of element :-");
                n=Integer.parseInt(br.readLine());
                if(n<=99)
                    {
                        for(i=0;i<n;i++)
                            {
                                System.out.print("Enter any no :-");
                                ar[i]=Integer.parseInt(br.readLine());
                            }
                        do
                            {
                                System.out.println("\n1.Ele insert...");
                                System.out.println("2.Ele delete...");
                                System.out.println("3.Ele display...");
                                System.out.println("4.Exit");
                                System.out.print("Enter your choice :-");
                                ch=Integer.parseInt(br.readLine());
                                switch(ch)
                                    {
                                        case 1:
                                            System.out.print("Enter position number :-");
                                            pos=Integer.parseInt(br.readLine());
                                            if(pos<n)
                                                {
                                                    for(j=n-1;j>=pos-1;j--)
                                                        ar[j+1]=ar[j];
                                                    System.out.print("Enter new inserting element :-");
                                                    ar[j+1]=Integer.parseInt(br.readLine());
                                                    n++;
                                                }
                                            else
                                                System.out.println("Sory invalid position number enterde.....");
                                            break;
                                        case 2:
                                            System.out.print("Enter position number :-");
                                            pos=Integer.parseInt(br.readLine());
                                            if(pos<n)
                                                {
                                                    for(j=pos-1;j<n;j++)
                                                        ar[j]=ar[j+1];
                                                    System.out.println("element deleted......");
                                                    n--;
                                                }
                                            else
                                                System.out.println("Sory invalid position number enterde.....");
                                            break;
                                        case 3:
                                            for(i=0;i<n;i++)
                                                System.out.print(ar[i]+"\t");
                                            System.out.println();
                                            break;
                                        case 4:
                                            System.out.println("Program end.......");
                                            break;
                                        default:
                                            System.out.println("Invalid enter select......");
                                    }
                            }while(ch != 4 );
                    }
                else
                    System.out.println("Out of range........");
                   
            }
    }