Removing potentially dangerous method

core/src/main/scala/org/apache/spark/util/ThreadUtils.scala

@@ -284,36 +284,12 @@ private[spark] object ThreadUtils {
     try {
       implicit val ec = ExecutionContext.fromExecutor(pool)
 
-      parmap(in)(f)
+      val futures = in.map(x => Future(f(x)))
+      val futureSeq = Future.sequence(futures)
+
+      awaitResult(futureSeq, Duration.Inf)
     } finally {
       pool.shutdownNow()
     }
   }
-
-  /**
-   * Transforms input collection by applying the given function to each element in parallel fashion.
-   * Comparing to the map() method of Scala parallel collections, this method can be interrupted
-   * at any time. This is useful on canceling of task execution, for example.
-   *
-   * @param in - the input collection which should be transformed in parallel.
-   * @param f - the lambda function will be applied to each element of `in`.
-   * @param ec - an execution context for parallel applying of the given function `f`.
-   * @tparam I - the type of elements in the input collection.
-   * @tparam O - the type of elements in resulted collection.
-   * @return new collection in which each element was given from the input collection `in` by
-   *         applying the lambda function `f`.
-   */
-  def parmap[I, O, Col[X] <: TraversableLike[X, Col[X]]]
-      (in: Col[I])
-      (f: I => O)
-      (implicit
-        cbf: CanBuildFrom[Col[I], Future[O], Col[Future[O]]], // For in.map
-        cbf2: CanBuildFrom[Col[Future[O]], O, Col[O]], // for Future.sequence
-        ec: ExecutionContext
-      ): Col[O] = {
-    val futures = in.map(x => Future(f(x)))
-    val futureSeq = Future.sequence(futures)
-
-    awaitResult(futureSeq, Duration.Inf)
-  }
 }

streaming/src/main/scala/org/apache/spark/streaming/util/FileBasedWriteAheadLog.scala

@@ -315,7 +315,9 @@ private[streaming] object FileBasedWriteAheadLog {
     implicit val ec = executionContext
 
     source.grouped(groupSize).flatMap { group =>
-      ThreadUtils.parmap(group)(handler)
+      val parallelCollection = group.par
+      parallelCollection.tasksupport = taskSupport
+      parallelCollection.map(handler)
     }.flatten
   }
 }