object Fut extends App {
  val f = new Fut
}

class Fut {

  import scala.concurrent.duration._
  import scala.concurrent._
  import scala.concurrent.ExecutionContext.Implicits.global

  val a:Future[Unit] = Future {
    "a's result" + Await.result(b,10.seconds)
  }
  val b:Future[Unit] = Future {
    "b's result" + Await.result(a,10.seconds)
  }

  println(Await.result(a,10.seconds))
  println(Await.result(b,10.seconds))

}

/*
  felix@felix-UX32VD:~/Desktop$ fsc Fut.scala
  felix@felix-UX32VD:~/Desktop$ scala Fut
  java.util.concurrent.TimeoutException: Futures timed out after [10 seconds]
      at scala.concurrent.impl.Promise$DefaultPromise.ready(Promise.scala:219)
  ...
*/