The problems of Future

Question
5

Thank you for the suggestions. It seems like the theory is true. The future still runs even when Await has timed out.

I realised that i have such poor understanding of Java concurrency. Is Scala Future using java concurrency libraries under the hood? How about libraries like cats-effect or ZIO or Monix? Do they have their own implementation of concurrency from the ground up?

If i want to understand more about all this should i pick up a book on Java concurrency? Because if libraries like cats-effect or ZIO or Monix have their own implementation from the ground up then what i will learn from Java concurrency might not be so relevant.

object Main extends App {

  import concurrent.duration._

  // single threaded execution context
  implicit val context: ExecutionContextExecutorService = {
    val executorService = Executors.newSingleThreadExecutor()
    ExecutionContext.fromExecutorService(executorService)
  }

  val f = Future {
    Thread.sleep(10.seconds.toMillis)
    println("Finish sleeping")
  }

  try {
    println(Await.result(f, 3.seconds))
  } catch {
    case _: Exception => println("Caught exception")
  }
  finally
   {
    println("Finished Await")
    context.shutdown()
  }

  println("At main")
}

Output

Caught exception
Finished Await
At main
//after 10 seconds
Finish sleeping