Should my Scala actors' properties be marked @volatile?

Question

In Scala, if I have a simple class as follows:

val calc = actor {
  var sum = 0
  loop {
    react {
      case Add(n) => 
        sum += n
      case Req         


        

Answer 1

You don't need to mark them as volatile. The execution of your code isn't inside a synchronized block, but the actor will always pass through one before your code is invoked, thus forcing memory into a consistent state across threads.