diff --git a/akka-actor/src/main/scala/akka/util/ByteIterator.scala b/akka-actor/src/main/scala/akka/util/ByteIterator.scala
index 13915335fa..a2bc455c38 100644
--- a/akka-actor/src/main/scala/akka/util/ByteIterator.scala
+++ b/akka-actor/src/main/scala/akka/util/ByteIterator.scala
@@ -68,7 +68,7 @@ object ByteIterator {
               this.clear()
               result
             }
-          case that: MultiByteArrayIterator ⇒ this +: that
+          case that: MultiByteArrayIterator ⇒ this ++: that
         }
       case _ ⇒ super.++(that)
     }
@@ -218,7 +218,7 @@ object ByteIterator {
       result
     }
 
-    def +:(that: ByteArrayIterator): this.type = {
+    private[akka] def ++:(that: ByteArrayIterator): this.type = {
       iterators = that +: iterators
       this
     }
diff --git a/akka-actor/src/main/scala/akka/util/ByteString.scala b/akka-actor/src/main/scala/akka/util/ByteString.scala
index dba4ed77f7..8aeed6daf2 100644
--- a/akka-actor/src/main/scala/akka/util/ByteString.scala
+++ b/akka-actor/src/main/scala/akka/util/ByteString.scala
@@ -77,7 +77,7 @@ object ByteString {
 
     override def iterator: ByteIterator.ByteArrayIterator = ByteIterator.ByteArrayIterator(bytes, 0, bytes.length)
 
-    def toByteString1: ByteString1 = ByteString1(bytes)
+    private[akka] def toByteString1: ByteString1 = ByteString1(bytes)
 
     override def clone: ByteString1C = new ByteString1C(toArray)