error_run.sh

scala> import scala.concurrent.Future
import scala.concurrent.Future

scala> import scala.util.{Failure, Success, Try}
import scala.util.{Failure, Success, Try}

scala> import scala.concurrent.ExecutionContext.Implicits.global
import scala.concurrent.ExecutionContext.Implicits.global

scala> 

scala> def fail = throw new RuntimeException("error now")
fail: Nothing

scala> 

scala> def failInFuture() = Future { throw new RuntimeException("error in future") }
failInFuture: ()scala.concurrent.Future[Nothing]

scala> 

scala> try {
     |   fail
     | } catch {
     |   case e: Exception => println(e.getMessage)
     | }
error now

scala> 

scala> failInFuture().onComplete {
     |   case Success(result) =>
     |   case Failure(t) => println("error reported in onComplete")
     | }
error reported in onComplete

scala> 

scala> failInFuture().onFailure {
     |   case e => println("error reported in onFailure")
     | }
error reported in onFailure

scala> 

scala> failInFuture().recover {
     |   case e => println("error reported in recover")
     | }
res24: scala.concurrent.Future[Unit] = scala.concurrent.impl.Promise$DefaultPromise@bd1111a
error reported in recover

scala> 

scala> 

scala> Try (fail).failed.map(e => println(e.getMessage))
error now
res25: scala.util.Try[Unit] = Success(())

scala> failInFuture().failed.map(e => println(e.getMessage))
error in future
res26: scala.concurrent.Future[Unit] = scala.concurrent.impl.Promise$DefaultPromise@65753040