/*Program to Reverse a given no. */
import java.io.*;
import java.lang.*;

class Reverse
{
    public static void main(String args[]) throws IOException
    {
      
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));

        System.out.println("Enter Number: ");
        int num=Integer.parseInt(br.readLine());

        int remainder, result=0;
        while(num>0)
        {
            remainder = num%10;
            result = result * 10 + remainder;
            num = num/10;
        }
        System.out.println("Reverse number is : "+result);
    }
}

 OUTPUT:

javac Reverse.java

java Reverse

Enter Number:
1234
Reverse number is : 4321