java help!

class Hello
{
   public static void main(String[] args)
   {
      System.out.printIn("Hello world!");
   }
}

Im a noob can someone help me make this work?

most efficient C pound version

class Program
{
    static void Main(string[] args)
    {
        System.Console.WriteLine("{0}{1}{2}{3}{4}{5}{6}{7}{8}{9}{10}{11}",
            'H', 'e', 'l', 'l', 'o', ' ', 'W', 'o', 'r', 'l', 'd', '!');
    }
}