MAPREDUCE-6213. NullPointerException caused by job history server addr not resolvable. Contributed by Peng Zhang.

(cherry picked from commit e1e09052e861926112493d6041aae01ab594b547)

hadoop-mapreduce-project/CHANGES.txt

@@ -38,6 +38,9 @@ Release 2.8.0 - UNRELEASED
 
   BUG FIXES
 
+    MAPREDUCE-6213. NullPointerException caused by job history server addr not
+    resolvable. (Peng Zhang via harsh)
+
     MAPREDUCE-6281. Fix javadoc in Terasort. (Albert Chu via ozawa)
 
 Release 2.7.0 - UNRELEASED

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-common/src/main/java/org/apache/hadoop/mapreduce/v2/util/MRWebAppUtil.java

@@ -137,8 +137,9 @@ public class MRWebAppUtil {
       hsAddress, getDefaultJHSWebappPort(),
       getDefaultJHSWebappURLWithoutScheme());
     StringBuffer sb = new StringBuffer();
-    if (address.getAddress().isAnyLocalAddress() || 
-        address.getAddress().isLoopbackAddress()) {
+    if (address.getAddress() != null &&
+        (address.getAddress().isAnyLocalAddress() ||
+         address.getAddress().isLoopbackAddress())) {
       sb.append(InetAddress.getLocalHost().getCanonicalHostName());
     } else {
       sb.append(address.getHostName());
@@ -171,4 +172,4 @@ public class MRWebAppUtil {
   public static String getAMWebappScheme(Configuration conf) {
     return "http://";
   }
-}
+}