YARN-1556. NPE getting application report with a null appId. Contributed by Weiwei Yang.

hadoop-yarn-project/CHANGES.txt

@@ -413,12 +413,15 @@ Release 2.8.0 - UNRELEASED
     YARN-4026. Refactored ContainerAllocator to accept a list of priorites
     rather than a single priority. (Wangda Tan via jianhe)
 
-   YARN-4031. Add JvmPauseMonitor to ApplicationHistoryServer and
-   WebAppProxyServer (djp via rkanter)
+    YARN-4031. Add JvmPauseMonitor to ApplicationHistoryServer and
+    WebAppProxyServer (djp via rkanter)
 
     YARN-4057. If ContainersMonitor is not enabled, only print
     related log info one time. (Jun Gong via zxu)
 
+    YARN-1556. NPE getting application report with a null appId. (Weiwei Yang via 
+    junping_du)
+
   OPTIMIZATIONS
 
     YARN-3339. TestDockerContainerExecutor should pull a single image and not

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/ClientRMService.java

@@ -315,6 +315,9 @@ public class ClientRMService extends AbstractService implements
   public GetApplicationReportResponse getApplicationReport(
       GetApplicationReportRequest request) throws YarnException {
     ApplicationId applicationId = request.getApplicationId();
+    if (applicationId == null) {
+      throw new ApplicationNotFoundException("Invalid application id: null");
+    }
 
     UserGroupInformation callerUGI;
     try {

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/TestClientRMService.java

@@ -333,6 +333,18 @@ public class TestClientRMService {
           report.getApplicationResourceUsageReport();
       Assert.assertEquals(10, usageReport.getMemorySeconds());
       Assert.assertEquals(3, usageReport.getVcoreSeconds());
+
+      // if application id is null
+      GetApplicationReportRequest invalidRequest = recordFactory
+          .newRecordInstance(GetApplicationReportRequest.class);
+      invalidRequest.setApplicationId(null);
+      try {
+        rmService.getApplicationReport(invalidRequest);
+      } catch (YarnException e) {
+        // rmService should return a ApplicationNotFoundException
+        // when a null application id is provided
+        Assert.assertTrue(e instanceof ApplicationNotFoundException);
+      }
     } finally {
       rmService.close();
     }