1 files changed, 8 insertions, 10 deletions
diff --git a/src/library/scala/collection/parallel/ParIterableLike.scala b/src/library/scala/collection/parallel/ParIterableLike.scala
index 44df7f7260..2ed7bc075e 100644
--- a/src/library/scala/collection/parallel/ParIterableLike.scala
+++ b/src/library/scala/collection/parallel/ParIterableLike.scala
@@ -9,6 +9,8 @@
 package scala
 package collection.parallel
 
+import scala.language.{ higherKinds, implicitConversions }
+
 import scala.collection.mutable.Builder
 import scala.collection.mutable.ArrayBuffer
 import scala.collection.IterableLike
@@ -21,13 +23,9 @@ import scala.collection.GenIterable
 import scala.collection.GenTraversableOnce
 import scala.collection.GenTraversable
 import immutable.HashMapCombiner
-import scala.reflect.{ClassTag, classTag}
-
-import java.util.concurrent.atomic.AtomicBoolean
+import scala.reflect.ClassTag
 
 import scala.annotation.unchecked.uncheckedVariance
-import scala.annotation.unchecked.uncheckedStable
-import scala.language.{ higherKinds, implicitConversions }
 
 import scala.collection.parallel.ParallelCollectionImplicits._
 
@@ -1284,7 +1282,7 @@ self: ParIterableLike[T, Repr, Sequential] =>
   extends Transformer[Combiner[(U, S), That], Zip[U, S, That]] {
     @volatile var result: Result = null
     def leaf(prev: Option[Result]) = result = pit.zip2combiner[U, S, That](othpit, pbf())
-    protected[this] def newSubtask(p: IterableSplitter[T]) = unsupported
+    protected[this] def newSubtask(p: IterableSplitter[T]) = throw new UnsupportedOperationException
     override def split = {
       val pits = pit.splitWithSignalling
       val sizes = pits.map(_.remaining)
@@ -1300,7 +1298,7 @@ self: ParIterableLike[T, Repr, Sequential] =>
   extends Transformer[Combiner[(U, S), That], ZipAll[U, S, That]] {
     @volatile var result: Result = null
     def leaf(prev: Option[Result]) = result = pit.zipAll2combiner[U, S, That](othpit, thiselem, thatelem, pbf())
-    protected[this] def newSubtask(p: IterableSplitter[T]) = unsupported
+    protected[this] def newSubtask(p: IterableSplitter[T]) = throw new UnsupportedOperationException
     override def split = if (pit.remaining <= len) {
       val pits = pit.splitWithSignalling
       val sizes = pits.map(_.remaining)
@@ -1322,7 +1320,7 @@ self: ParIterableLike[T, Repr, Sequential] =>
   extends Accessor[Unit, CopyToArray[U, This]] {
     @volatile var result: Unit = ()
     def leaf(prev: Option[Unit]) = pit.copyToArray(array, from, len)
-    protected[this] def newSubtask(p: IterableSplitter[T]) = unsupported
+    protected[this] def newSubtask(p: IterableSplitter[T]) = throw new UnsupportedOperationException
     override def split = {
       val pits = pit.splitWithSignalling
       for ((p, untilp) <- pits zip pits.scanLeft(0)(_ + _.remaining); if untilp < len) yield {
@@ -1379,7 +1377,7 @@ self: ParIterableLike[T, Repr, Sequential] =>
       val half = howmany / 2
       ScanNode(mergeTrees(trees, from, half), mergeTrees(trees, from + half, howmany - half))
     } else trees(from)
-    protected[this] def newSubtask(pit: IterableSplitter[T]) = unsupported
+    protected[this] def newSubtask(pit: IterableSplitter[T]) = throw new UnsupportedOperationException
     override def split = {
       val pits = pit.splitWithSignalling
       for ((p, untilp) <- pits zip pits.scanLeft(from)(_ + _.remaining)) yield {
@@ -1416,7 +1414,7 @@ self: ParIterableLike[T, Repr, Sequential] =>
         new FromScanTree(left, z, op, cbf),
         new FromScanTree(right, z, op, cbf)
       )
-      case _ => unsupportedop("Cannot be split further")
+      case _ => throw new UnsupportedOperationException("Cannot be split further")
     }
     def shouldSplitFurther = tree match {
       case ScanNode(_, _) => true