diff --git a/core/src/main/scala/org/apache/spark/rpc/RpcEnv.scala b/core/src/main/scala/org/apache/spark/rpc/RpcEnv.scala
index afe1ee8a0b4d..35e402c72533 100644
--- a/core/src/main/scala/org/apache/spark/rpc/RpcEnv.scala
+++ b/core/src/main/scala/org/apache/spark/rpc/RpcEnv.scala
@@ -38,8 +38,6 @@ private[spark] object RpcEnv {
     // Add more RpcEnv implementations here
     val rpcEnvNames = Map("akka" -> "org.apache.spark.rpc.akka.AkkaRpcEnvFactory",
       "netty" -> "org.apache.spark.rpc.netty.NettyRpcEnvFactory")
-    // Use "netty" by default so that Jenkins can run all tests using NettyRpcEnv.
-    // Will change it back to "akka" before merging the new implementation.
     val rpcEnvName = conf.get("spark.rpc", "netty")
     val rpcEnvFactoryClassName = rpcEnvNames.getOrElse(rpcEnvName.toLowerCase, rpcEnvName)
     Utils.classForName(rpcEnvFactoryClassName).newInstance().asInstanceOf[RpcEnvFactory]
diff --git a/core/src/test/scala/org/apache/spark/rpc/netty/InboxSuite.scala b/core/src/test/scala/org/apache/spark/rpc/netty/InboxSuite.scala
index ff83ab9b32cb..120cf1b6fa9d 100644
--- a/core/src/test/scala/org/apache/spark/rpc/netty/InboxSuite.scala
+++ b/core/src/test/scala/org/apache/spark/rpc/netty/InboxSuite.scala
@@ -90,9 +90,11 @@ class InboxSuite extends SparkFunSuite {
         }
       }.start()
     }
+    // Try to process some messages
     inbox.process(dispatcher)
-    assert(inbox.isEmpty)
     inbox.stop()
+    // After `stop` is called, further messages will be dropped. However, while `stop` is called,
+    // some messages may be post to Inbox, so process them here.
     inbox.process(dispatcher)
     assert(inbox.isEmpty)