JAVA: Reading integer from the keyboard without using Integer.ParseInt() method

import java.io.*;

public class readIntegerWithoutUsingParseint {

    public static void main(String args[]) throws IOException{
         BufferedReader input = new BufferedReader(new InputStreamReader(System.in));
         String integer = input.readLine();
         char ar[]= integer.toCharArray();
         int x = (int)'0';
         int sum = 1;
         int number=0;
         
         for(int i=(ar.length-1); i>=0; i--){
         number = number + (sum)*((int)ar[i]-x);
         sum = sum*10;
         }

         System.out.println(number);

    }
}