Future.scala

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

object Main extends App {

 def foo(x: Int): Future[Int] =
   Future {
     println(s"x: $x")
     Thread.sleep(300)
     if(x < 3) x + 1
     else throw new RuntimeException
   }


  println(Await.result(foo(0).flatMap(foo), Duration.Inf))
  println(Await.result(foo(0).flatMap(foo).flatMap(foo).flatMap(foo), Duration.Inf))
}

/*
s: 0
s: 1
2
s: 0
s: 1
s: 2
s: 3
java.lang.RuntimeException
        at Main$.$anonfun$foo$1(Main.scala:12)
        at scala.runtime.java8.JFunction0$mcI$sp.apply(JFunction0$mcI$sp.java:23)
        at scala.concurrent.Future$.$anonfun$apply$1(Future.scala:658)
        at scala.util.Success.$anonfun$map$1(Try.scala:255)
        at scala.util.Success.map(Try.scala:213)
        at scala.concurrent.Future.$anonfun$map$1(Future.scala:292)
        at scala.concurrent.impl.Promise.liftedTree1$1(Promise.scala:33)
        at scala.concurrent.impl.Promise.$anonfun$transform$1(Promise.scala:33)
        at scala.concurrent.impl.CallbackRunnable.run(Promise.scala:64)
        at java.util.concurrent.ForkJoinTask$RunnableExecuteAction.exec(ForkJoinTask.java:1402)
        at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289)
        at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1056)
        at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1692)
        at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:157)
*/

Try.scala

scala> import scala.util.Try
import scala.util.Try

scala> import scala.util.Failure
import scala.util.Failure

scala> def foo(x: Int): Try[Int] = if(x < 3) Try(x + 1) else Failure(new RuntimeException)
foo: (x: Int)scala.util.Try[Int]

scala> foo(0).flatMap(foo)
res10: scala.util.Try[Int] = Success(2)

scala> foo(0).flatMap(foo).flatMap(foo)
res11: scala.util.Try[Int] = Success(3)

scala> foo(0).flatMap(foo).flatMap(foo).flatMap(foo)
res12: scala.util.Try[Int] = Failure(java.lang.RuntimeException)

scala> foo(0).flatMap(foo).flatMap(foo).flatMap(foo).flatMap(foo)
res13: scala.util.Try[Int] = Failure(java.lang.RuntimeException)