title: Akka HelloWorld Not Compiling :-(
body: <p>Been trying to get to grips with AKKA over the last few days and the Actor Model I get, I get communication through messages etc but I'm dammed if I can get just a simple HelloWorld project to compile. Here's the single helloWorld.java file... I have included both classes(Actors) in here...</p>
  
  <pre><code>import akka.actor.Props;
  import akka.actor.UntypedActor;
  import akka.actor.ActorRef;
  
  public class helloWorld extends UntypedActor {
  
    @Override
    public void preStart() {
      // create the greeter actor
      final ActorRef greeter =
          getContext().actorOf(Props.create(Greeter.class), "greeter");
      // tell it to perform the greeting
      greeter.tell(Greeter.Msg.GREET, getSelf());
    }
  
    @Override
    public void onReceive(Object msg) {
      if (msg == Greeter.Msg.DONE) {
        // when the greeter is done, stop this actor and with it the application
        getContext().stop(getSelf());
      } else unhandled(msg);
    }
  }
  
  public class Greeter extends UntypedActor {
  
    public static enum Msg {
      GREET, DONE;
    }
  
    @Override
    public void onReceive(Object msg) {
      if (msg == Msg.GREET) {
        System.out.println("Hello World!");
        getSender().tell(Msg.DONE, getSelf());
      } else unhandled(msg);
    }
  
  }
  </code></pre>
  
  <p>Here's the command I'm using in Terminal (Ubunut)...</p>
  
  <pre><code>java -classpath $AKKA_HOME/lib/scala-library.jar:$AKKA_HOME/lib/akka/akka-actor_2.10-2.2.1.jar:$AKKA_HOME/lib/akka/config-1.0.2.jar akka.Main helloWorld
  </code></pre>
  
  <p>And here's the exception I'm getting...</p>
  
  <pre><code>Exception in thread "main" java.lang.ClassNotFoundException: helloWorld
      at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
      at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
      at java.security.AccessController.doPrivileged(Native Method)
      at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
      at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
      at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
      at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
      at java.lang.Class.forName0(Native Method)
      at java.lang.Class.forName(Class.java:270)
      at akka.actor.ReflectiveDynamicAccess$$anonfun$getClassFor$1.apply(DynamicAccess.scala:67)
      at akka.actor.ReflectiveDynamicAccess$$anonfun$getClassFor$1.apply(DynamicAccess.scala:66)
      at scala.util.Try$.apply(Try.scala:161)
      at akka.actor.ReflectiveDynamicAccess.getClassFor(DynamicAccess.scala:66)
      at akka.Main$.main(Main.scala:32)
      at akka.Main.main(Main.scala)
  </code></pre>
  
  <p>Can anyone offer any advice?</p>
  
  <p>Thanks in advance</p>