javaFutureToFuture.scala

def someFuture(input: String): Future[String] = {
  val promise = new Promise[String]
  
  val javaFuture = someJavaFutureMethod(input)
  
  // Use Timer to periodically check for return value of 
  timer.schedule(10.millis) {
    if (javaFuture.isDone()) {
      // Probably glossing over some edge cases around setting interrupts, timeouts, etc.. but you get the gist
      begin {
        promise.setValue(javaFuture.get())
      } rescue {
        case ex => promise.setException(ex)
      }
    }
    
  }

  promise
}