imports here are messy, this should work:

    import java.io.File
    import java.util.UUID

    import scala.language.postfixOps

    import scala.collection.{immutable, mutable}
    import scala.concurrent.duration._
    import scala.util.{Failure, Success}

    import akka.actor._
    import akka.actor.OneForOneStrategy
    import akka.actor.SupervisorStrategy._
    import akka.cluster.{Member, Cluster}
    import akka.cluster.ClusterEvent.{CurrentClusterState, MemberRemoved, MemberUp, RoleLeaderChanged}
    import akka.contrib.pattern.DistributedPubSubExtension
    import akka.contrib.pattern.DistributedPubSubMediator.Subscribe
    import akka.util.Timeout

    import org.apache.spark.{SparkException, Logging}
    import org.apache.spark.metrics.MetricsSystem
    import org.apache.spark.deploy.{ApplicationDescription, ExecutorState}
    import org.apache.spark.deploy.DeployMessages._
    import org.apache.spark.deploy.master._
    import org.apache.spark.deploy.worker.Topics._
    import org.apache.spark.deploy.worker.ui.WorkerWebUI
    import org.apache.spark.util.AkkaUtils
    import org.apache.spark.util.Utils