diff --git a/akka-actor/src/main/scala/akka/dispatch/Mailboxes.scala b/akka-actor/src/main/scala/akka/dispatch/Mailboxes.scala
index 1c385aff14..d978bec07c 100644
--- a/akka-actor/src/main/scala/akka/dispatch/Mailboxes.scala
+++ b/akka-actor/src/main/scala/akka/dispatch/Mailboxes.scala
@@ -135,7 +135,7 @@ private[akka] class Mailboxes(
     // TODO remove in 2.3
     if (!hasMailboxType && !mailboxSizeWarningIssued && dispatcherConfig.hasPath("mailbox-size")) {
       eventStream.publish(Warning("mailboxes", getClass,
-        "ignoring setting 'mailbox-size' for dispatcher [$id], you need to specify 'mailbox-type=bounded'"))
+        s"ignoring setting 'mailbox-size' for dispatcher [$id], you need to specify 'mailbox-type=bounded'"))
       mailboxSizeWarningIssued = true
     }
 
diff --git a/akka-actor/src/main/scala/akka/util/Reflect.scala b/akka-actor/src/main/scala/akka/util/Reflect.scala
index 8c62375d64..1c5d11fb26 100644
--- a/akka-actor/src/main/scala/akka/util/Reflect.scala
+++ b/akka-actor/src/main/scala/akka/util/Reflect.scala
@@ -125,7 +125,7 @@ private[akka] object Reflect {
         case c: Class[_] if marker isAssignableFrom c ⇒ c
         case t: ParameterizedType if marker isAssignableFrom t.getRawType.asInstanceOf[Class[_]] ⇒ t
       } match {
-        case None                       ⇒ throw new IllegalArgumentException("cannot find [$marker] in ancestors of [$root]")
+        case None                       ⇒ throw new IllegalArgumentException(s"cannot find [$marker] in ancestors of [$root]")
         case Some(c: Class[_])          ⇒ if (c == marker) c else rec(c)
         case Some(t: ParameterizedType) ⇒ if (t.getRawType == marker) t else rec(t.getRawType.asInstanceOf[Class[_]])
         case _                          ⇒ ??? // cannot happen due to collectFirst