Is a way to return Future[Unit]?

Question

I have a method returning Unit originally. After changing returned type to Future[Unit], I can't find out a way to change the method body. The least line is a method call.

Answer 1

In Scala 2.12 the built-in Future.unit is the way to go. It has the benefit of being cached.

Answer 2

You can return a Future that holds a value of Unit

def doSomething():Future[Unit] = {
  TimeUnit.SECONDS.sleep(3)
  println("hi")
  Future.successful(())
}