implementing Concurrent Modifications in a Scala Collection while Using Akka Actors
I've searched everywhere and can't find a clear answer. Quick question that's been bugging me - I'm working with a question with concurrent modifications in a Scala `ListBuffer` when using it within Akka actors. I have a scenario where multiple actors are trying to update the same `ListBuffer`. Here is a simplified version of the code: ```scala import akka.actor.{Actor, ActorSystem, Props} import scala.collection.mutable.ListBuffer class MyActor(buffer: ListBuffer[Int]) extends Actor { def receive = { case num: Int => buffer += num } } object Main extends App { val system = ActorSystem("MySystem") val sharedBuffer = ListBuffer[Int]() val actor1 = system.actorOf(Props(new MyActor(sharedBuffer)), "actor1") val actor2 = system.actorOf(Props(new MyActor(sharedBuffer)), "actor2") actor1 ! 1 actor2 ! 2 } ``` When I run this code, sometimes I get unexpected behavior where the updates to the `ListBuffer` do not reflect correctly. In fact, at times, I see a `java.util.ConcurrentModificationException`. I know that `ListBuffer` is not thread-safe, but I was hoping to manage this in a simple manner. I tried wrapping the updates in a synchronized block: ```scala buffer.synchronized { buffer += num } ``` However, this did not resolve the scenario, and I still see the `ConcurrentModificationException` appearing intermittently. I've also considered using a `Vector` instead, but I'm unsure if it will perform better or if I might end up with the same scenario due to immutability concerns. Is there a better approach to handle concurrent modifications in this scenario? Should I be using a different data structure or synchronization mechanism? Any insights would be greatly appreciated! For context: I'm using Scala on Linux. I'd really appreciate any guidance on this. My development environment is macOS. Am I missing something obvious? Am I missing something obvious?