implementing Lazy Val Initialization in Scala 2.13 When Using Futures
Hey everyone, I'm running into an issue that's driving me crazy. I recently switched to I'm integrating two systems and I'm working with a strange scenario with lazy val initialization in my Scala 2.13 application that uses Futures... I have a lazy val that initializes a resource when accessed, but the initialization sometimes seems to execute multiple times, leading to unexpected behavior. Here's a simplified version of my code: ```scala import scala.concurrent.{Future, ExecutionContext} import scala.util.{Success, Failure} object LazyValExample { implicit val ec: ExecutionContext = ExecutionContext.global lazy val resource: String = { println("Initializing resource...") "Resource" } def useResource(): Future[Unit] = Future { println(resource) // Accessing the lazy val } def main(args: Array[String]): Unit = { val futures = Seq(useResource(), useResource(), useResource()) Future.sequence(futures).onComplete { case Success(_) => println("All done") case Failure(ex) => println(s"Failed with: ${ex.getMessage}") } } } ``` When I run this code, I expect "Initializing resource..." to print only once, but I see it printed multiple times. I’ve tried using `@volatile` on the lazy val, but it doesn’t seem to help in this context. I suspect the scenario might be related to the thread execution context, but I’m not entirely sure how to address it. Is there a recommended approach to ensure that the lazy val is initialized only once when accessed concurrently? Any suggestions or insights would be greatly appreciated! I recently upgraded to Scala stable. I'm working with Scala in a Docker container on CentOS. I appreciate any insights! For reference, this is a production REST API.