I have a code, where I create an Actor from AkkaSystem.
return system.actorOf(Props.apply(new Creator<Actor>()
....
Inside the child actor I call
context().parent().tell(new DeathByError());
context().stop(self());
is there a way to know from the parent (ActorSystem object) to know that child sent DeathByError message ?
When you are handling the message you can call getSender() which should return the ActorRef of the one who sent the message.
If you meant "what" child sent the message, Micheal Rose's answer is correct.
If you simply want to receive it, add a handler for it in the parents receive method.
Note that if you "watch" an actor from another actor, the latter is notified when the former dies, without need for you to explicitly sending a message ( http://doc.akka.io/docs/akka/current/scala/actors.html#Actor_Lifecycle )