http://b.ja.rtur.me/scalas-call-by-name-and-mutable-context/

0_actor_problem.scala

class MyActor(ref: ActorRef) extends Actor {
  def receive: Receive = {
    case Bifurcate =>
    context.actorOf(Props[MyActor](new MyActor(sender)))
  }
}

1_actor_correct.scala

class MyActor(ref: ActorRef) extends Actor {
  def receive: Receive = {
    case Bifurcate =>
    context.actorOf(Props(classOf[MyActor], sender))
  }
}