Kamon has not been started yet.

gistfile1.scala

//BAD
object Boot {
  implicit val system = ActorSystem("test")

  def main(args: Array[String]): Unit = {
    Kamon.start()

    class ApplicationServer(val actorSystem: ActorSystem) extends Stuff
    new ApplicationServer(system)
    system.shutdown()

    Kamon.shutdown()
  }
}


//GOOD
object Boot {

  def main(args: Array[String]): Unit = {
    Kamon.start()

    implicit val system = ActorSystem("test")
    class ApplicationServer(val actorSystem: ActorSystem) extends Stuff
    new ApplicationServer(system)
    system.shutdown()

    Kamon.shutdown()
  }
}