YARN-8348. Incorrect and missing AfterClass in HBase-tests to fix NPE failures. Contributed by Giovanni Matteo Fumarola.

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice-hbase-tests/src/test/java/org/apache/hadoop/yarn/server/timelineservice/storage/TestHBaseTimelineStorageApps.java

@@ -1936,6 +1936,8 @@ public class TestHBaseTimelineStorageApps {
 
   @AfterClass
   public static void tearDownAfterClass() throws Exception {
-    util.shutdownMiniCluster();
+    if (util != null) {
+      util.shutdownMiniCluster();
+    }
   }
 }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice-hbase-tests/src/test/java/org/apache/hadoop/yarn/server/timelineservice/storage/TestHBaseTimelineStorageDomain.java

@@ -32,6 +32,7 @@ import org.apache.hadoop.yarn.server.timelineservice.storage.common.ColumnRWHelp
 import org.apache.hadoop.yarn.server.timelineservice.storage.domain.DomainColumn;
 import org.apache.hadoop.yarn.server.timelineservice.storage.domain.DomainRowKey;
 import org.apache.hadoop.yarn.server.timelineservice.storage.domain.DomainTableRW;
+import org.junit.AfterClass;
 import org.junit.BeforeClass;
 import org.junit.Test;
 
@@ -123,4 +124,11 @@ public class TestHBaseTimelineStorageDomain {
     assertEquals("user1,user2 group1,group2", readers);
     assertEquals("writer1,writer2", writers);
   }
+
+  @AfterClass
+  public static void tearDownAfterClass() throws Exception {
+    if (util != null) {
+      util.shutdownMiniCluster();
+    }
+  }
 }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice-hbase-tests/src/test/java/org/apache/hadoop/yarn/server/timelineservice/storage/TestHBaseTimelineStorageEntities.java

@@ -1879,7 +1879,9 @@ public class TestHBaseTimelineStorageEntities {
 
   @AfterClass
   public static void tearDownAfterClass() throws Exception {
-    util.shutdownMiniCluster();
+    if (util != null) {
+      util.shutdownMiniCluster();
+    }
   }
 
   private boolean verifyRowKeyForSubApplication(byte[] rowKey, String suAppUser,

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice-hbase-tests/src/test/java/org/apache/hadoop/yarn/server/timelineservice/storage/TestHBaseTimelineStorageSchema.java

@@ -24,6 +24,7 @@ import static org.junit.Assert.assertTrue;
 import org.apache.hadoop.yarn.server.timelineservice.storage.common.BaseTableRW;
 import org.apache.hadoop.yarn.server.timelineservice.storage.entity.EntityTableRW;
 import org.apache.hadoop.yarn.server.timelineservice.storage.flow.FlowRunTableRW;
+import org.junit.AfterClass;
 import org.junit.BeforeClass;
 import org.junit.Test;
 
@@ -137,4 +138,11 @@ public class TestHBaseTimelineStorageSchema {
     hbaseConf
     .unset(YarnConfiguration.TIMELINE_SERVICE_HBASE_SCHEMA_PREFIX_NAME);
   }
+
+  @AfterClass
+  public static void tearDownAfterClass() throws Exception {
+    if (util != null) {
+      util.shutdownMiniCluster();
+    }
+  }
 }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice-hbase-tests/src/test/java/org/apache/hadoop/yarn/server/timelineservice/storage/flow/TestHBaseStorageFlowActivity.java

@@ -492,6 +492,8 @@ public class TestHBaseStorageFlowActivity {
 
   @AfterClass
   public static void tearDownAfterClass() throws Exception {
-    util.shutdownMiniCluster();
+    if (util != null) {
+      util.shutdownMiniCluster();
+    }
   }
 }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice-hbase-tests/src/test/java/org/apache/hadoop/yarn/server/timelineservice/storage/flow/TestHBaseStorageFlowRun.java

@@ -1075,6 +1075,8 @@ public class TestHBaseStorageFlowRun {
 
   @AfterClass
   public static void tearDownAfterClass() throws Exception {
-    util.shutdownMiniCluster();
+    if (util != null) {
+      util.shutdownMiniCluster();
+    }
   }
 }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice-hbase-tests/src/test/java/org/apache/hadoop/yarn/server/timelineservice/storage/flow/TestHBaseStorageFlowRunCompaction.java

@@ -850,6 +850,8 @@ public class TestHBaseStorageFlowRunCompaction {
 
   @AfterClass
   public static void tearDownAfterClass() throws Exception {
-    util.shutdownMiniCluster();
+    if (util != null) {
+      util.shutdownMiniCluster();
+    }
   }
 }