diff --git a/transport/src/test/java/io/netty/channel/ChannelOutboundBufferTest.java b/transport/src/test/java/io/netty/channel/ChannelOutboundBufferTest.java
index e9dae042c4..fd46ef0069 100644
--- a/transport/src/test/java/io/netty/channel/ChannelOutboundBufferTest.java
+++ b/transport/src/test/java/io/netty/channel/ChannelOutboundBufferTest.java
@@ -346,7 +346,7 @@ public class ChannelOutboundBufferTest {
     private static void safeClose(EmbeddedChannel ch) {
         ch.finish();
         for (;;) {
-            ByteBuf m = ch.readOutbound();
+            ByteBuf m = (ByteBuf) ch.readOutbound();
             if (m == null) {
                 break;
             }