1 files changed, 11 insertions, 0 deletions
diff --git a/src/library/scala/collection/concurrent/Map.scala b/src/library/scala/collection/concurrent/Map.scala
index cfb567abe9..f27dfd57fc 100644
--- a/src/library/scala/collection/concurrent/Map.scala
+++ b/src/library/scala/collection/concurrent/Map.scala
@@ -86,4 +86,15 @@ trait Map[A, B] extends scala.collection.mutable.Map[A, B] {
    * @return    `Some(v)` if the given key was previously mapped to some value `v`, or `None` otherwise
    */
   def replace(k: A, v: B): Option[B]
+
+  override def getOrElseUpdate(key: A, op: =>B): B = get(key) match {
+    case Some(v) => v
+    case None =>
+      val v = op
+      putIfAbsent(key, v) match {
+        case Some(nv) => nv
+        case None => v
+      }
+  }
+
 }