Sum of digits of a number in java

Java code to add all digits of a numbers 

import java.io.*;



class Test {

     public static void main(String[] args) throws IOException {

         

          int num,sum=0,r;

          System.out.println("Enter a number:");

          BufferedReader br=new BufferedReader(new InputStreamReader (System.in));

          num=Integer.parseInt(br.readLine());



          while(num!=0){