From 5c8d90763c52f6bf5224b59738739bd2d1a4b4b8 Mon Sep 17 00:00:00 2001
From: Akira Ajisaka <aajisaka@apache.org>
Date: Fri, 28 Sep 2018 10:02:56 +0900
Subject: [PATCH] HADOOP-15764. Addendum patch: Fix NPE in SecurityUtil.

---
 .../java/org/apache/hadoop/security/SecurityUtil.java  | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/SecurityUtil.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/SecurityUtil.java
index 9fea535ec0..2313119bfe 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/SecurityUtil.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/SecurityUtil.java
@@ -586,12 +586,14 @@ public InetAddress getByName(String host) throws UnknownHostException {
    *       hadoop.security.token.service.use_ip=false 
    */
   protected static class QualifiedHostResolver implements HostResolver {
-    private List<String> searchDomains;
+    private List<String> searchDomains = new ArrayList<>();
     {
       ResolverConfig resolverConfig = ResolverConfig.getCurrentConfig();
-      searchDomains = new ArrayList<>();
-      for (Name name : resolverConfig.searchPath()) {
-        searchDomains.add(name.toString());
+      Name[] names = resolverConfig.searchPath();
+      if (names != null) {
+        for (Name name : names) {
+          searchDomains.add(name.toString());
+        }
       }
     }