Greeting greeting1 = (Greeting) inbox.receive(Duration.create(5, TimeUnit.SECONDS));
System.out.println("Greeting: " + greeting1.message);
// Change the greeting and ask for it again
greeter.tell(new WhoToGreet("typesafe"), ActorRef.noSender());
inbox.send(greeter, new Greet());
Greeting greeting2 = (Greeting) inbox.receive(Duration.create(5, TimeUnit.SECONDS));
System.out.println("Greeting: " + greeting2.message);
// after zero seconds, send a Greet message every second to the greeter with a sender of the GreetPrinter
ActorRef greetPrinter = system.actorOf(Props.create(GreetPrinter.class));