Java program to convert Binary number to Decimal

Write a program which convert Binary number to Decimal in java?

package javatute;

import java.io.IOException;

import java.util.Scanner;

public class BinaryToDecimal {
	
	public static void main(String[] args) throws IOException {
		
		Scanner in = new Scanner(System.in);
		
		System.out.print("Enter a Binary number");
		
		String s = in.nextLine();
		
		long n = Long.parseLong(s);
		
		long r;
		
		while (n > 0) {
			
			r = n % 10;
			
			n = n / 10;
			
			if (r != 0 && r != 1) {
				
				System.out.println("This is not a binary numberber");
				
			}
			
		}
		
		int i = Integer.parseInt(s, 2);
		
		System.out.println("Decimal:" + i);
		
	}
	
}