diff --git a/core/src/main/scala/org/apache/spark/rpc/netty/Outbox.scala b/core/src/main/scala/org/apache/spark/rpc/netty/Outbox.scala
index 7d9d593b36241..c769594640c63 100644
--- a/core/src/main/scala/org/apache/spark/rpc/netty/Outbox.scala
+++ b/core/src/main/scala/org/apache/spark/rpc/netty/Outbox.scala
@@ -53,6 +53,7 @@ private[netty] class Outbox(nettyEnv: NettyRpcEnv, val address: RpcAddress) {
    */
   @GuardedBy("this")
   private var draining = false
+  private val outboxStoppedEx = new SparkException("Message is dropped because Outbox is stopped")
 
   /**
    * Send a message. If there is no active connection, cache it and launch a new connection. If
@@ -68,7 +69,7 @@ private[netty] class Outbox(nettyEnv: NettyRpcEnv, val address: RpcAddress) {
       }
     }
     if (dropped) {
-      message.callback.onFailure(new SparkException("Message is dropped because Outbox is stopped"))
+      message.callback.onFailure(outboxStoppedEx)
     } else {
       drainOutbox()
     }
@@ -160,7 +161,7 @@ private[netty] class Outbox(nettyEnv: NettyRpcEnv, val address: RpcAddress) {
   }
 
   /**
-   * Stop [[Inbox]] and notify the waiting messages with the cause.
+   * Stop [[Outbox]] and notify the waiting messages with the cause.
    */
   private def handleNetworkFailure(e: Throwable): Unit = {
     synchronized {
@@ -215,7 +216,7 @@ private[netty] class Outbox(nettyEnv: NettyRpcEnv, val address: RpcAddress) {
     // update messages and it's safe to just drain the queue.
     var message = messages.poll()
     while (message != null) {
-      message.callback.onFailure(new SparkException("Message is dropped because Outbox is stopped"))
+      message.callback.onFailure(outboxStoppedEx)
       message = messages.poll()
     }
   }