From cb3f3cca01d6ab9f4befb1bcd31f384c37c0231a Mon Sep 17 00:00:00 2001
From: Wei-Chiu Chuang <weichiu@apache.org>
Date: Tue, 18 Feb 2020 21:53:08 -0800
Subject: [PATCH] HADOOP-16868. ipc.Server readAndProcess threw
 NullPointerException. Contributed by Tsz-wo Sze.

---
 .../src/main/java/org/apache/hadoop/ipc/Server.java            | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ipc/Server.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ipc/Server.java
index fb339c02f2..4448164f4b 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ipc/Server.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ipc/Server.java
@@ -1794,7 +1794,7 @@ public class Connection {
 
     private SocketChannel channel;
     private ByteBuffer data;
-    private ByteBuffer dataLengthBuffer;
+    private final ByteBuffer dataLengthBuffer;
     private LinkedList<RpcCall> responseQueue;
     // number of outstanding rpcs
     private AtomicInteger rpcCount = new AtomicInteger();
@@ -2838,7 +2838,6 @@ public void setServiceClass(int serviceClass) {
     private synchronized void close() {
       disposeSasl();
       data = null;
-      dataLengthBuffer = null;
       if (!channel.isOpen())
         return;
       try {socket.shutdownOutput();} catch(Exception e) {