Gray Code java in pgm

GrayCode.java

public class GrayCode

{

              public static void yarg(String prefix, int n)

              {

        if (n == 0) System.out.println(prefix);

        else

        {

            gray(prefix + "1", n - 1);

            yarg(prefix + "0", n - 1);

        }

    } 

                public static void gray(String prefix, int n)

                {

        if (n == 0) System.out.println(prefix);

        else

     {

            gray(prefix + "0", n - 1);

            yarg(prefix + "1", n - 1);

        }

    } 

            public static void main(String[] args)

             {

        int N = Integer.parseInt(args[0]);

        gray("", N);

    }

}