Gray Code Checker

package miscellaneous;
import java.util.Scanner;

public class GrayCodeMain
{
    public static void main(String... args)
    {
        String a = "", b = "";
        Scanner scan = new Scanner(System.in);
        System.out.print("Enter the first 8-bit number: ");
        a = scan.next();
        System.out.print("\nEnter the second 8-bit number: ");
        if(scan.hasNext())
            b = scan.next();
        System.out.print("\nIs one the Gray code of the other?: ");
        if(GrayCode.checkGray(a, b))
            System.out.print("Yes.");
        else
            System.out.print("No.");
    }
}

class GrayCode
{
    static boolean checkGray(String a, String b)
    {
        long first = Long.parseLong(a, 2);
        long second = Long.parseLong(b, 2);

        long encode_1 = encode(first);
        long encode_2 = encode(second);
        long decode_1 = decode(first);
        long decode_2 = decode(second);

        if((encode_1 == second) || (encode_2 == first))
            return true;
        if((decode_1 == second) || (decode_2 == first))
            return true;

        return false;
    }

    static long encode(long n)
    {
        long p = n ^ (n >>> 1);
        return p;
    }

    static long decode(long n)
    {
        long p = n;
        while((n >>> 1) != 0)
            p ^= n;
        return p;
    }
}