diff --git a/akka-actor/src/main/scala/akka/dispatch/Future.scala b/akka-actor/src/main/scala/akka/dispatch/Future.scala
index a925978b24..d745f8ec4a 100644
--- a/akka-actor/src/main/scala/akka/dispatch/Future.scala
+++ b/akka-actor/src/main/scala/akka/dispatch/Future.scala
@@ -685,6 +685,7 @@ class DefaultCompletableFuture[T](timeout: Long, timeunit: TimeUnit) extends Com
       }
     }
 
+    @tailrec
     def runCallbacks(rest: List[Future[T] => Unit], callbacks: Stack[() => Unit]) {
       if (rest.nonEmpty) {
         notify(rest.head)