From b0f20399e7c2aab624e6e3eda6b1838b40c41faf Mon Sep 17 00:00:00 2001
From: Bo Cui <cuibo0108@163.com>
Date: Mon, 23 Nov 2020 12:07:42 +0800
Subject: [PATCH] HBASE-25311 UI throws NPE (#2688)

Signed-off-by: Guanghao Zhang <zghao@apache.org>
Signed-off-by: Wellington Chevreuil <wellington.chevreuil@gmail.com>
Signed-off-by: Viraj Jasani <vjasani@apache.org>
---
 .../java/org/apache/hadoop/hbase/master/HMaster.java  | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/hbase-server/src/main/java/org/apache/hadoop/hbase/master/HMaster.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/master/HMaster.java
index bbd8c0e4fbb..7adbeb0ce87 100644
--- a/hbase-server/src/main/java/org/apache/hadoop/hbase/master/HMaster.java
+++ b/hbase-server/src/main/java/org/apache/hadoop/hbase/master/HMaster.java
@@ -3621,8 +3621,15 @@ public class HMaster extends HRegionServer implements MasterServices {
       List<ReplicationLoadSource> replicationLoadSources =
           getServerManager().getLoad(serverName).getReplicationLoadSourceList();
       for (ReplicationLoadSource replicationLoadSource : replicationLoadSources) {
-        replicationLoadSourceMap.get(replicationLoadSource.getPeerID())
-            .add(new Pair<>(serverName, replicationLoadSource));
+        List<Pair<ServerName, ReplicationLoadSource>> replicationLoadSourceList =
+          replicationLoadSourceMap.get(replicationLoadSource.getPeerID());
+        if (replicationLoadSourceList == null) {
+          LOG.debug("{} does not exist, but it exists "
+            + "in znode(/hbase/replication/rs). when the rs restarts, peerId is deleted, so "
+            + "we just need to ignore it", replicationLoadSource.getPeerID());
+          continue;
+        }
+        replicationLoadSourceList.add(new Pair<>(serverName, replicationLoadSource));
       }
     }
     for (List<Pair<ServerName, ReplicationLoadSource>> loads : replicationLoadSourceMap.values()) {