HBASE-27252 Clean up error-prone findings in hbase-it

Close #4662

Co-authored-by: Duo Zhang <zhangduo@apache.org>
Signed-off-by: Duo Zhang <zhangduo@apache.org>
Signed-off-by: Viraj Jasani <vjasani@apache.org>

hbase-it/src/main/java/org/apache/hadoop/hbase/chaos/ChaosAgent.java

@@ -19,6 +19,7 @@ package org.apache.hadoop.hbase.chaos;
 
 import java.io.Closeable;
 import java.io.IOException;
+import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.concurrent.atomic.AtomicBoolean;
@@ -224,10 +225,11 @@ public class ChaosAgent implements Watcher, Closeable, Runnable {
           } catch (Exception e) {
             break;
           }
-          zk.getData(path, false, getTaskForExecutionCallback, new String(data));
+          zk.getData(path, false, getTaskForExecutionCallback,
+            new String(data, StandardCharsets.UTF_8));
           break;
         case OK:
-          String cmd = new String(data);
+          String cmd = new String(data, StandardCharsets.UTF_8);
           LOG.info("Executing command : " + cmd);
           String status = ChaosConstants.TASK_COMPLETION_STRING;
           try {
@@ -368,7 +370,8 @@ public class ChaosAgent implements Watcher, Closeable, Runnable {
    */
   public void setStatusOfTaskZNode(String taskZNode, String status) {
     LOG.info("Setting status of Task ZNode: " + taskZNode + " status : " + status);
-    zk.setData(taskZNode, status.getBytes(), -1, setStatusOfTaskZNodeCallback, null);
+    zk.setData(taskZNode, status.getBytes(StandardCharsets.UTF_8), -1, setStatusOfTaskZNodeCallback,
+      null);
   }
 
   /**

hbase-it/src/test/java/org/apache/hadoop/hbase/ChaosZKClient.java

@@ -18,6 +18,7 @@
 package org.apache.hadoop.hbase;
 
 import java.io.IOException;
+import java.nio.charset.StandardCharsets;
 import org.apache.hadoop.hbase.util.EnvironmentEdgeManager;
 import org.apache.hadoop.hbase.util.Threads;
 import org.apache.yetus.audience.InterfaceAudience;
@@ -111,7 +112,7 @@ public class ChaosZKClient {
       zk.create(
         CHAOS_AGENT_STATUS_ZNODE + ZNODE_PATH_SEPARATOR + taskObject.getTaskHostname()
           + ZNODE_PATH_SEPARATOR + TASK_PREFIX,
-        taskObject.getCommand().getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE,
+        taskObject.getCommand().getBytes(StandardCharsets.UTF_8), ZooDefs.Ids.OPEN_ACL_UNSAFE,
         CreateMode.EPHEMERAL_SEQUENTIAL, submitTaskCallback, taskObject);
       long start = EnvironmentEdgeManager.currentTime();
 
@@ -189,7 +190,7 @@ public class ChaosZKClient {
       case OK:
         if (ctx != null) {
 
-          String status = new String(data);
+          String status = new String(data, StandardCharsets.UTF_8);
           taskStatus = status;
           switch (status) {
             case TASK_COMPLETION_STRING:

hbase-it/src/test/java/org/apache/hadoop/hbase/ClusterManager.java

@@ -40,7 +40,7 @@ interface ClusterManager extends Configurable {
     HBASE_MASTER("master"),
     HBASE_REGIONSERVER("regionserver");
 
-    private String name;
+    private final String name;
 
     ServiceType(String name) {
       this.name = name;

hbase-it/src/test/java/org/apache/hadoop/hbase/DistributedHBaseCluster.java

@@ -344,9 +344,9 @@ public class DistributedHBaseCluster extends HBaseClusterInterface {
 
     // do a best effort restore
     boolean success = true;
-    success = restoreMasters(initial, current) & success;
+    success = restoreMasters(initial, current) && success;
-    success = restoreRegionServers(initial, current) & success;
+    success = restoreRegionServers(initial, current) && success;
-    success = restoreAdmin() & success;
+    success = restoreAdmin() && success;
 
     LOG.info("Restoring cluster - done");
     return success;

hbase-it/src/test/java/org/apache/hadoop/hbase/HBaseClusterManager.java

@@ -280,22 +280,14 @@ public class HBaseClusterManager extends Configured implements ClusterManager {
    */
   static class ZookeeperShellCommandProvider extends CommandProvider {
     private final String zookeeperHome;
-    private final String confDir;
 
     ZookeeperShellCommandProvider(Configuration conf) throws IOException {
       zookeeperHome =
         conf.get("hbase.it.clustermanager.zookeeper.home", System.getenv("ZOOBINDIR"));
-      String tmp =
-        conf.get("hbase.it.clustermanager.zookeeper.conf.dir", System.getenv("ZOOCFGDIR"));
       if (zookeeperHome == null) {
         throw new IOException("ZooKeeper home configuration parameter i.e. "
           + "'hbase.it.clustermanager.zookeeper.home' is not configured properly.");
       }
-      if (tmp != null) {
-        confDir = String.format("--config %s", tmp);
-      } else {
-        confDir = "";
-      }
     }
 
     @Override

hbase-it/src/test/java/org/apache/hadoop/hbase/IntegrationTestBackupRestore.java

@@ -244,14 +244,12 @@ public class IntegrationTestBackupRestore extends IntegrationTestBase {
   private void runTestSingle(TableName table) throws IOException {
 
     List<String> backupIds = new ArrayList<String>();
-    List<Integer> tableSizes = new ArrayList<Integer>();
 
     try (Connection conn = util.getConnection(); Admin admin = conn.getAdmin();
       BackupAdmin client = new BackupAdminImpl(conn);) {
 
       // #0- insert some data to table 'table'
       loadData(table, rowsInIteration);
-      tableSizes.add(rowsInIteration);
 
       // #1 - create full backup for table first
       LOG.info("create full backup image for {}", table);
@@ -270,7 +268,6 @@ public class IntegrationTestBackupRestore extends IntegrationTestBase {
 
         // Load data
         loadData(table, rowsInIteration);
-        tableSizes.add(rowsInIteration * count);
         // Do incremental backup
         builder = new BackupRequest.Builder();
         request = builder.withBackupType(BackupType.INCREMENTAL).withTableList(tables)
@@ -321,10 +318,7 @@ public class IntegrationTestBackupRestore extends IntegrationTestBase {
     return arr;
   }
 
-  /**
+  /** Returns status of backup */
-   * @param backupId pass backup ID to check status of
-   * @return status of backup
-   */
   protected boolean checkSucceeded(String backupId) throws IOException {
     BackupInfo status = getBackupInfo(backupId);
     if (status == null) {
@@ -428,9 +422,6 @@ public class IntegrationTestBackupRestore extends IntegrationTestBase {
       .add(NUMBER_OF_TABLES_KEY, numTables).add(SLEEP_TIME_KEY, sleepTime).toString());
   }
 
-  /**
-   * @param args argument list
-   */
   public static void main(String[] args) throws Exception {
     Configuration conf = HBaseConfiguration.create();
     IntegrationTestingUtility.setUseDistributedCluster(conf);

hbase-it/src/test/java/org/apache/hadoop/hbase/IntegrationTestIngest.java

@@ -36,6 +36,7 @@ import org.junit.experimental.categories.Category;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import org.apache.hbase.thirdparty.com.google.common.base.Splitter;
 import org.apache.hbase.thirdparty.com.google.common.collect.Sets;
 
 /**
@@ -63,7 +64,6 @@ public class IntegrationTestIngest extends IntegrationTestBase {
 
   // Log is being used in IntegrationTestIngestWithEncryption, hence it is protected
   protected static final Logger LOG = LoggerFactory.getLogger(IntegrationTestIngest.class);
-  protected IntegrationTestingUtility util;
   protected HBaseClusterInterface cluster;
   protected LoadTestTool loadTool;
 
@@ -137,7 +137,7 @@ public class IntegrationTestIngest extends IntegrationTestBase {
         families.add(Bytes.toString(family));
       }
     } else {
-      for (String family : familiesString.split(",")) {
+      for (String family : Splitter.on(',').split(familiesString)) {
         families.add(family);
       }
     }
@@ -168,8 +168,7 @@ public class IntegrationTestIngest extends IntegrationTestBase {
       LOG.info("Intended run time: " + (runtime / 60000) + " min, left:"
         + ((runtime - (EnvironmentEdgeManager.currentTime() - start)) / 60000) + " min");
 
-      int ret = -1;
+      int ret = loadTool.run(getArgsForLoadTestTool("-write",
-      ret = loadTool.run(getArgsForLoadTestTool("-write",
         String.format("%d:%d:%d", colsPerKey, recordSize, writeThreads), startKey, numKeys));
       if (0 != ret) {
         String errorMsg = "Load failed with error code " + ret;

hbase-it/src/test/java/org/apache/hadoop/hbase/IntegrationTestIngestWithMOB.java

@@ -105,6 +105,7 @@ public class IntegrationTestIngestWithMOB extends IntegrationTestIngest {
   }
 
   @Test
+  @Override
   public void testIngest() throws Exception {
     runIngestTest(JUNIT_RUN_TIME, 100, 10, 1024, 10, 20);
   }

hbase-it/src/test/java/org/apache/hadoop/hbase/IntegrationTestLazyCfLoading.java

@@ -58,7 +58,9 @@ import org.slf4j.LoggerFactory;
 public class IntegrationTestLazyCfLoading {
   private static final TableName TABLE_NAME =
     TableName.valueOf(IntegrationTestLazyCfLoading.class.getSimpleName());
+  @SuppressWarnings("InlineFormatString")
   private static final String TIMEOUT_KEY = "hbase.%s.timeout";
+  @SuppressWarnings("InlineFormatString")
   private static final String ENCODING_KEY = "hbase.%s.datablock.encoding";
 
   /** A soft test timeout; duration of the test, as such, depends on number of keys to put. */

hbase-it/src/test/java/org/apache/hadoop/hbase/IntegrationTestMobCompaction.java

@@ -21,6 +21,7 @@ import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertTrue;
 
 import java.io.IOException;
+import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
 import java.util.Set;
 import org.apache.hadoop.conf.Configuration;
@@ -226,7 +227,7 @@ public class IntegrationTestMobCompaction extends IntegrationTestBase {
 
   }
 
-  class MajorCompaction implements Runnable {
+  static class MajorCompaction implements Runnable {
 
     @Override
     public void run() {
@@ -242,7 +243,7 @@ public class IntegrationTestMobCompaction extends IntegrationTestBase {
     }
   }
 
-  class CleanMobAndArchive implements Runnable {
+  static class CleanMobAndArchive implements Runnable {
 
     @Override
     public void run() {
@@ -257,7 +258,7 @@ public class IntegrationTestMobCompaction extends IntegrationTestBase {
 
           Thread.sleep(130000);
         } catch (Exception e) {
-          e.printStackTrace();
+          LOG.warn("Exception in CleanMobAndArchive", e);
         }
       }
     }
@@ -288,7 +289,8 @@ public class IntegrationTestMobCompaction extends IntegrationTestBase {
             try {
               Thread.sleep(500);
             } catch (InterruptedException ee) {
-
+              // Restore interrupt status
+              Thread.currentThread().interrupt();
             }
           }
           if (i % 100000 == 0) {
@@ -323,7 +325,7 @@ public class IntegrationTestMobCompaction extends IntegrationTestBase {
         Thread.sleep(1000);
       }
 
-      getNumberOfMobFiles(conf, table.getName(), new String(fam));
+      getNumberOfMobFiles(conf, table.getName(), new String(fam, StandardCharsets.UTF_8));
       LOG.info("Waiting for write thread to finish ...");
       writeData.join();
       // Cleanup again

hbase-it/src/test/java/org/apache/hadoop/hbase/IntegrationTestRegionReplicaPerf.java

@@ -23,9 +23,9 @@ import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertTrue;
 
 import com.codahale.metrics.Histogram;
+import java.util.ArrayDeque;
 import java.util.ArrayList;
 import java.util.Arrays;
-import java.util.LinkedList;
 import java.util.List;
 import java.util.Queue;
 import java.util.Set;
@@ -104,7 +104,7 @@ public class IntegrationTestRegionReplicaPerf extends IntegrationTestBase {
    * Wraps the invocation of {@link PerformanceEvaluation} in a {@code Callable}.
    */
   static class PerfEvalCallable implements Callable<TimingResult> {
-    private final Queue<String> argv = new LinkedList<>();
+    private final Queue<String> argv = new ArrayDeque<>();
     private final Admin admin;
 
     public PerfEvalCallable(Admin admin, String argv) {

hbase-it/src/test/java/org/apache/hadoop/hbase/IntegrationTestRegionReplicaReplication.java

@@ -175,7 +175,6 @@ public class IntegrationTestRegionReplicaReplication extends IntegrationTestInge
 
       int verifyPercent = 100;
       int updatePercent = 20;
-      int ret = -1;
       int regionReplicaId =
         conf.getInt(String.format("%s.%s", TEST_NAME, LoadTestTool.OPT_REGION_REPLICA_ID), 1);
 
@@ -191,7 +190,7 @@ public class IntegrationTestRegionReplicaReplication extends IntegrationTestInge
       args.add("-" + LoadTestTool.OPT_REGION_REPLICA_ID);
       args.add(String.valueOf(regionReplicaId));
 
-      ret = loadTool.run(args.toArray(new String[args.size()]));
+      int ret = loadTool.run(args.toArray(new String[args.size()]));
       if (0 != ret) {
         String errorMsg = "Load failed with error code " + ret;
         LOG.error(errorMsg);

hbase-it/src/test/java/org/apache/hadoop/hbase/IntegrationTestingUtility.java

@@ -116,14 +116,13 @@ public class IntegrationTestingUtility extends HBaseTestingUtil {
   }
 
   /**
-   * @return whether we are interacting with a distributed cluster as opposed to and in-process mini
+   * Returns whether we are interacting with a distributed cluster as opposed to and in-process mini
-   *         cluster or a local cluster.
+   * cluster or a local cluster.
    * @see IntegrationTestingUtility#setUseDistributedCluster(Configuration)
    */
   public boolean isDistributedCluster() {
     Configuration conf = getConfiguration();
-    boolean isDistributedCluster = false;
+    boolean isDistributedCluster =
-    isDistributedCluster =
       Boolean.parseBoolean(System.getProperty(IS_DISTRIBUTED_CLUSTER, "false"));
     if (!isDistributedCluster) {
       isDistributedCluster = conf.getBoolean(IS_DISTRIBUTED_CLUSTER, false);

hbase-it/src/test/java/org/apache/hadoop/hbase/IntegrationTestsDriver.java

@@ -47,7 +47,7 @@ public class IntegrationTestsDriver extends AbstractHBaseTool {
     System.exit(ret);
   }
 
-  private class IntegrationTestFilter extends ClassTestFinder.TestClassFilter {
+  private static class IntegrationTestFilter extends ClassTestFinder.TestClassFilter {
     private Pattern testFilterRe = Pattern.compile(".*\\.IntegrationTest.*");
 
     public IntegrationTestFilter() {

hbase-it/src/test/java/org/apache/hadoop/hbase/StripeCompactionsPerformanceEvaluation.java

@@ -18,6 +18,7 @@
 package org.apache.hadoop.hbase;
 
 import java.io.IOException;
+import java.util.List;
 import java.util.Locale;
 import java.util.Set;
 import org.apache.commons.lang3.StringUtils;
@@ -43,6 +44,8 @@ import org.junit.Assert;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import org.apache.hbase.thirdparty.com.google.common.base.Splitter;
+import org.apache.hbase.thirdparty.com.google.common.collect.Iterables;
 import org.apache.hbase.thirdparty.org.apache.commons.cli.CommandLine;
 
 /**
@@ -108,10 +111,12 @@ public class StripeCompactionsPerformanceEvaluation extends AbstractHBaseTool {
     int minValueSize = 0, maxValueSize = 0;
     String valueSize = cmd.getOptionValue(VALUE_SIZE_KEY, VALUE_SIZE_DEFAULT);
     if (valueSize.contains(":")) {
-      String[] valueSizes = valueSize.split(":");
+      List<String> valueSizes = Splitter.on(':').splitToList(valueSize);
-      if (valueSize.length() != 2) throw new RuntimeException("Invalid value size: " + valueSize);
+      if (valueSizes.size() != 2) {
-      minValueSize = Integer.parseInt(valueSizes[0]);
+        throw new RuntimeException("Invalid value size: " + valueSize);
-      maxValueSize = Integer.parseInt(valueSizes[1]);
+      }
+      minValueSize = Integer.parseInt(Iterables.get(valueSizes, 0));
+      maxValueSize = Integer.parseInt(Iterables.get(valueSizes, 1));
     } else {
       minValueSize = maxValueSize = Integer.parseInt(valueSize);
     }

hbase-it/src/test/java/org/apache/hadoop/hbase/TestShellExecEndpointCoprocessor.java

@@ -23,6 +23,7 @@ import static org.junit.Assert.assertTrue;
 
 import java.io.File;
 import java.io.IOException;
+import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
@@ -106,7 +107,8 @@ public class TestShellExecEndpointCoprocessor {
     assertFalse("the response from a background task should have no stderr", resp.hasStderr());
 
     Waiter.waitFor(conn.getConfiguration(), 5_000, () -> testFile.length() > 0);
-    final String content = new String(Files.readAllBytes(testFile.toPath())).trim();
+    final String content =
+      new String(Files.readAllBytes(testFile.toPath()), StandardCharsets.UTF_8).trim();
     assertEquals("hello world", content);
   }
 

hbase-it/src/test/java/org/apache/hadoop/hbase/chaos/actions/Action.java

@@ -21,7 +21,6 @@ import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashSet;
-import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
 import java.util.Properties;
@@ -277,13 +276,13 @@ public abstract class Action {
 
   protected void unbalanceRegions(ClusterMetrics clusterStatus, List<ServerName> fromServers,
     List<ServerName> toServers, double fractionOfRegions) throws Exception {
-    List<byte[]> victimRegions = new LinkedList<>();
+    List<byte[]> victimRegions = new ArrayList<>();
     for (Map.Entry<ServerName, ServerMetrics> entry : clusterStatus.getLiveServerMetrics()
       .entrySet()) {
       ServerName sn = entry.getKey();
       ServerMetrics serverLoad = entry.getValue();
       // Ugh.
-      List<byte[]> regions = new LinkedList<>(serverLoad.getRegionMetrics().keySet());
+      List<byte[]> regions = new ArrayList<>(serverLoad.getRegionMetrics().keySet());
       int victimRegionCount = (int) Math.ceil(fractionOfRegions * regions.size());
       getLogger().debug("Removing {} regions from {}", victimRegionCount, sn);
       Random rand = ThreadLocalRandom.current();

hbase-it/src/test/java/org/apache/hadoop/hbase/chaos/actions/AddCPULoadAction.java

@@ -28,6 +28,7 @@ import org.slf4j.LoggerFactory;
  */
 public class AddCPULoadAction extends SudoCommandAction {
   private static final Logger LOG = LoggerFactory.getLogger(AddCPULoadAction.class);
+  @SuppressWarnings("InlineFormatString")
   private static final String CPU_LOAD_COMMAND =
     "seq 1 %s | xargs -I{} -n 1 -P %s timeout %s dd if=/dev/urandom of=/dev/null bs=1M "
       + "iflag=fullblock";
@@ -51,6 +52,7 @@ public class AddCPULoadAction extends SudoCommandAction {
     return LOG;
   }
 
+  @Override
   protected void localPerform() throws IOException {
     getLogger().info("Starting to execute AddCPULoadAction");
     ServerName server = PolicyBasedChaosMonkey.selectRandomItem(getCurrentServers());

hbase-it/src/test/java/org/apache/hadoop/hbase/chaos/actions/ChangeBloomFilterAction.java

@@ -28,16 +28,10 @@ import org.slf4j.LoggerFactory;
  * Action that tries to adjust the bloom filter setting on all the columns of a table
  */
 public class ChangeBloomFilterAction extends Action {
-  private final long sleepTime;
-  private final TableName tableName;
   private static final Logger LOG = LoggerFactory.getLogger(ChangeBloomFilterAction.class);
+  private final TableName tableName;
 
   public ChangeBloomFilterAction(TableName tableName) {
-    this(-1, tableName);
-  }
-
-  public ChangeBloomFilterAction(int sleepTime, TableName tableName) {
-    this.sleepTime = sleepTime;
     this.tableName = tableName;
   }
 

hbase-it/src/test/java/org/apache/hadoop/hbase/chaos/actions/CorruptPacketsCommandAction.java

@@ -50,6 +50,7 @@ public class CorruptPacketsCommandAction extends TCCommandAction {
     return LOG;
   }
 
+  @Override
   protected void localPerform() throws IOException {
     getLogger().info("Starting to execute CorruptPacketsCommandAction");
     ServerName server = PolicyBasedChaosMonkey.selectRandomItem(getCurrentServers());

hbase-it/src/test/java/org/apache/hadoop/hbase/chaos/actions/DelayPacketsCommandAction.java

@@ -50,6 +50,7 @@ public class DelayPacketsCommandAction extends TCCommandAction {
     return LOG;
   }
 
+  @Override
   protected void localPerform() throws IOException {
     getLogger().info("Starting to execute DelayPacketsCommandAction");
     ServerName server = PolicyBasedChaosMonkey.selectRandomItem(getCurrentServers());

hbase-it/src/test/java/org/apache/hadoop/hbase/chaos/actions/DuplicatePacketsCommandAction.java

@@ -50,6 +50,7 @@ public class DuplicatePacketsCommandAction extends TCCommandAction {
     return LOG;
   }
 
+  @Override
   protected void localPerform() throws IOException {
     getLogger().info("Starting to execute DuplicatePacketsCommandAction");
     ServerName server = PolicyBasedChaosMonkey.selectRandomItem(getCurrentServers());

hbase-it/src/test/java/org/apache/hadoop/hbase/chaos/actions/FillDiskCommandAction.java

@@ -54,6 +54,7 @@ public class FillDiskCommandAction extends SudoCommandAction {
     return LOG;
   }
 
+  @Override
   protected void localPerform() throws IOException {
     getLogger().info("Starting to execute FillDiskCommandAction");
     ServerName server = PolicyBasedChaosMonkey.selectRandomItem(getCurrentServers());

hbase-it/src/test/java/org/apache/hadoop/hbase/chaos/actions/LosePacketsCommandAction.java

@@ -50,6 +50,7 @@ public class LosePacketsCommandAction extends TCCommandAction {
     return LOG;
   }
 
+  @Override
   protected void localPerform() throws IOException {
     getLogger().info("Starting to execute LosePacketsCommandAction");
     ServerName server = PolicyBasedChaosMonkey.selectRandomItem(getCurrentServers());

hbase-it/src/test/java/org/apache/hadoop/hbase/chaos/actions/ReorderPacketsCommandAction.java

@@ -54,6 +54,7 @@ public class ReorderPacketsCommandAction extends TCCommandAction {
     return LOG;
   }
 
+  @Override
   protected void localPerform() throws IOException {
     getLogger().info("Starting to execute ReorderPacketsCommandAction");
     ServerName server = PolicyBasedChaosMonkey.selectRandomItem(getCurrentServers());

hbase-it/src/test/java/org/apache/hadoop/hbase/chaos/actions/RestartRandomDataNodeAction.java

@@ -18,7 +18,7 @@
 package org.apache.hadoop.hbase.chaos.actions;
 
 import java.io.IOException;
-import java.util.LinkedList;
+import java.util.ArrayList;
 import java.util.List;
 import org.apache.hadoop.hbase.ServerName;
 import org.apache.hadoop.hbase.chaos.monkies.PolicyBasedChaosMonkey;
@@ -56,7 +56,7 @@ public class RestartRandomDataNodeAction extends RestartActionBaseAction {
     DistributedFileSystem fs =
       (DistributedFileSystem) CommonFSUtils.getRootDir(getConf()).getFileSystem(getConf());
     DFSClient dfsClient = fs.getClient();
-    List<ServerName> hosts = new LinkedList<>();
+    List<ServerName> hosts = new ArrayList<>();
     for (DatanodeInfo dataNode : dfsClient.datanodeReport(HdfsConstants.DatanodeReportType.LIVE)) {
       hosts.add(ServerName.valueOf(dataNode.getHostName(), -1, -1));
     }

hbase-it/src/test/java/org/apache/hadoop/hbase/chaos/actions/RollingBatchRestartRsAction.java

@@ -18,6 +18,7 @@
 package org.apache.hadoop.hbase.chaos.actions;
 
 import java.io.IOException;
+import java.util.ArrayDeque;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.LinkedList;
@@ -66,11 +67,13 @@ public class RollingBatchRestartRsAction extends BatchRestartRsAction {
   }
 
   @Override
+  // deadServers is both list and queue here, a valid use case for LinkedList
+  @SuppressWarnings("JdkObsolete")
   public void perform() throws Exception {
     getLogger().info("Performing action: Rolling batch restarting {}% of region servers",
       (int) (ratio * 100));
     List<ServerName> selectedServers = selectServers();
-    Queue<ServerName> serversToBeKilled = new LinkedList<>(selectedServers);
+    Queue<ServerName> serversToBeKilled = new ArrayDeque<>(selectedServers);
     LinkedList<ServerName> deadServers = new LinkedList<>();
     Random rand = ThreadLocalRandom.current();
     // loop while there are servers to be killed or dead servers to be restarted

hbase-it/src/test/java/org/apache/hadoop/hbase/chaos/actions/RollingBatchSuspendResumeRsAction.java

@@ -18,7 +18,7 @@
 package org.apache.hadoop.hbase.chaos.actions;
 
 import java.io.IOException;
-import java.util.LinkedList;
+import java.util.ArrayDeque;
 import java.util.List;
 import java.util.Queue;
 import java.util.Random;
@@ -68,8 +68,8 @@ public class RollingBatchSuspendResumeRsAction extends Action {
     getLogger().info("Performing action: Rolling batch restarting {}% of region servers",
       (int) (ratio * 100));
     List<ServerName> selectedServers = selectServers();
-    Queue<ServerName> serversToBeSuspended = new LinkedList<>(selectedServers);
+    Queue<ServerName> serversToBeSuspended = new ArrayDeque<>(selectedServers);
-    Queue<ServerName> suspendedServers = new LinkedList<>();
+    Queue<ServerName> suspendedServers = new ArrayDeque<>();
     Random rand = ThreadLocalRandom.current();
     // loop while there are servers to be suspended or suspended servers to be resumed
     while (

hbase-it/src/test/java/org/apache/hadoop/hbase/chaos/actions/SplitAllRegionOfTableAction.java

@@ -38,6 +38,7 @@ public class SplitAllRegionOfTableAction extends Action {
     this.tableName = tableName;
   }
 
+  @Override
   public void init(ActionContext context) throws IOException {
     super.init(context);
     this.maxFullTableSplits = getConf().getInt(MAX_SPLIT_KEY, DEFAULT_MAX_SPLITS);

hbase-it/src/test/java/org/apache/hadoop/hbase/chaos/actions/UnbalanceKillAndRebalanceAction.java

@@ -19,7 +19,6 @@ package org.apache.hadoop.hbase.chaos.actions;
 
 import java.util.ArrayList;
 import java.util.HashSet;
-import java.util.LinkedList;
 import java.util.List;
 import java.util.Random;
 import java.util.Set;
@@ -66,7 +65,7 @@ public class UnbalanceKillAndRebalanceAction extends Action {
   @Override
   public void perform() throws Exception {
     ClusterMetrics status = this.cluster.getClusterMetrics();
-    List<ServerName> victimServers = new LinkedList<>(status.getLiveServerMetrics().keySet());
+    List<ServerName> victimServers = new ArrayList<>(status.getLiveServerMetrics().keySet());
     Set<ServerName> killedServers = new HashSet<>();
     int liveCount = (int) Math.ceil(FRC_SERVERS_THAT_HOARD_AND_LIVE * victimServers.size());
     int deadCount = (int) Math.ceil(FRC_SERVERS_THAT_HOARD_AND_DIE * victimServers.size());

hbase-it/src/test/java/org/apache/hadoop/hbase/chaos/actions/UnbalanceRegionsAction.java

@@ -18,7 +18,6 @@
 package org.apache.hadoop.hbase.chaos.actions;
 
 import java.util.ArrayList;
-import java.util.LinkedList;
 import java.util.List;
 import java.util.Random;
 import java.util.concurrent.ThreadLocalRandom;
@@ -55,7 +54,7 @@ public class UnbalanceRegionsAction extends Action {
   public void perform() throws Exception {
     getLogger().info("Unbalancing regions");
     ClusterMetrics status = this.cluster.getClusterMetrics();
-    List<ServerName> victimServers = new LinkedList<>(status.getLiveServerMetrics().keySet());
+    List<ServerName> victimServers = new ArrayList<>(status.getLiveServerMetrics().keySet());
     int targetServerCount = (int) Math.ceil(fractionOfServers * victimServers.size());
     List<ServerName> targetServers = new ArrayList<>(targetServerCount);
     Random rand = ThreadLocalRandom.current();

hbase-it/src/test/java/org/apache/hadoop/hbase/chaos/factories/ConfigurableSlowDeterministicMonkeyFactory.java

@@ -18,12 +18,16 @@
 package org.apache.hadoop.hbase.chaos.factories;
 
 import java.lang.reflect.Constructor;
+import java.util.List;
 import java.util.function.Function;
 import org.apache.hadoop.hbase.TableName;
 import org.apache.hadoop.hbase.chaos.actions.Action;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import org.apache.hbase.thirdparty.com.google.common.base.Splitter;
+import org.apache.hbase.thirdparty.com.google.common.collect.Iterables;
+
 public class ConfigurableSlowDeterministicMonkeyFactory extends SlowDeterministicMonkeyFactory {
 
   private static final Logger LOG =
@@ -32,6 +36,7 @@ public class ConfigurableSlowDeterministicMonkeyFactory extends SlowDeterministi
   final static String HEAVY_ACTIONS = "heavy.actions";
   final static String TABLE_PARAM = "\\$table_name";
 
+  @SuppressWarnings("ImmutableEnumChecker")
   public enum SupportedTypes {
     FLOAT(p -> Float.parseFloat(p)),
     LONG(p -> Long.parseLong(p)),
@@ -56,12 +61,13 @@ public class ConfigurableSlowDeterministicMonkeyFactory extends SlowDeterministi
       return super.getHeavyWeightedActions();
     } else {
       try {
-        String[] actionClasses = actions.split(";");
+        List<String> actionClasses = Splitter.on(';').splitToList(actions);
-        Action[] heavyActions = new Action[actionClasses.length];
+        Action[] heavyActions = new Action[actionClasses.size()];
-        for (int i = 0; i < actionClasses.length; i++) {
+        int i = 0;
-          heavyActions[i] = instantiateAction(actionClasses[i]);
+        for (String action : actionClasses) {
+          heavyActions[i++] = instantiateAction(action);
         }
-        LOG.info("Created actions {}", heavyActions);
+        LOG.info("Created actions {}", (Object[]) heavyActions); // non-varargs call to LOG#info
         return heavyActions;
       } catch (Exception e) {
         LOG.error("Error trying to instantiate heavy actions. Returning null array.", e);
@@ -72,10 +78,13 @@ public class ConfigurableSlowDeterministicMonkeyFactory extends SlowDeterministi
 
   private Action instantiateAction(String actionString) throws Exception {
     final String packageName = "org.apache.hadoop.hbase.chaos.actions";
-    String[] classAndParams = actionString.split("\\)")[0].split("\\(");
+    Iterable<String> classAndParams =
-    String className = packageName + "." + classAndParams[0];
+      Splitter.on('(').split(Iterables.get(Splitter.on(')').split(actionString), 0));
-    String[] params =
+    String className = packageName + "." + Iterables.get(classAndParams, 0);
-      classAndParams[1].replaceAll(TABLE_PARAM, tableName.getNameAsString()).split(",");
+    String[] params = Splitter.on(',')
+      .splitToStream(
+        Iterables.get(classAndParams, 1).replaceAll(TABLE_PARAM, tableName.getNameAsString()))
+      .toArray(String[]::new);
     LOG.info("About to instantiate action class: {}; With constructor params: {}", className,
       params);
     Class<? extends Action> actionClass = (Class<? extends Action>) Class.forName(className);

hbase-it/src/test/java/org/apache/hadoop/hbase/chaos/util/ChaosMonkeyRunner.java

@@ -167,7 +167,7 @@ public class ChaosMonkeyRunner extends AbstractHBaseTool {
     return Sets.newHashSet(familyName);
   }
 
-  /*
+  /**
    * If caller wants to add config parameters from a file, the path to the conf file can be passed
    * like this: -c <path-to-conf>. The file is presumed to have the Configuration file xml format
    * and is added as a new Resource to the current Configuration. Use this mechanism to set

hbase-it/src/test/java/org/apache/hadoop/hbase/ipc/IntegrationTestRpcClient.java

@@ -124,8 +124,8 @@ public class IntegrationTestRpcClient {
     }
 
     void stopRandomServer() throws Exception {
-      lock.writeLock().lock();
       RpcServer rpcServer = null;
+      lock.writeLock().lock();
       try {
         if (rpcServers.size() <= minServers) {
           return;
@@ -243,6 +243,7 @@ public class IntegrationTestRpcClient {
     }
 
     @Override
+    @SuppressWarnings("AssertionFailureIgnored") // intended
     public void run() {
       while (running.get()) {
         boolean isBigPayload = ThreadLocalRandom.current().nextBoolean();

hbase-it/src/test/java/org/apache/hadoop/hbase/mapreduce/IntegrationTestBulkLoad.java

@@ -365,7 +365,7 @@ public class IntegrationTestBulkLoad extends IntegrationTestBase {
       taskId = taskId + iteration * numMapTasks;
       numMapTasks = numMapTasks * numIterations;
 
-      long chainId = Math.abs(ThreadLocalRandom.current().nextLong());
+      long chainId = ThreadLocalRandom.current().nextLong(Long.MAX_VALUE);
       chainId = chainId - (chainId % numMapTasks) + taskId; // ensure that chainId is unique per
                                                             // task and across iterations
       LongWritable[] keys = new LongWritable[] { new LongWritable(chainId) };

hbase-it/src/test/java/org/apache/hadoop/hbase/mapreduce/IntegrationTestImportTsv.java

@@ -40,7 +40,6 @@ import org.apache.hadoop.hbase.CellComparator;
 import org.apache.hadoop.hbase.HBaseConfiguration;
 import org.apache.hadoop.hbase.IntegrationTestingUtility;
 import org.apache.hadoop.hbase.KeyValue;
-import org.apache.hadoop.hbase.KeyValue.Type;
 import org.apache.hadoop.hbase.TableName;
 import org.apache.hadoop.hbase.client.Result;
 import org.apache.hadoop.hbase.client.Scan;
@@ -60,6 +59,8 @@ import org.junit.rules.TestName;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import org.apache.hbase.thirdparty.com.google.common.base.Splitter;
+
 /**
  * Validate ImportTsv + BulkLoadFiles on a distributed cluster.
  */
@@ -83,13 +84,13 @@ public class IntegrationTestImportTsv extends Configured implements Tool {
       private static final long serialVersionUID = 1L;
       {
         byte[] family = Bytes.toBytes("d");
-        for (String line : simple_tsv.split("\n")) {
+        for (String line : Splitter.on('\n').split(simple_tsv)) {
           String[] row = line.split("\t");
           byte[] key = Bytes.toBytes(row[0]);
           long ts = Long.parseLong(row[1]);
           byte[][] fields = { Bytes.toBytes(row[2]), Bytes.toBytes(row[3]) };
-          add(new KeyValue(key, family, fields[0], ts, Type.Put, fields[0]));
+          add(new KeyValue(key, family, fields[0], ts, KeyValue.Type.Put, fields[0]));
-          add(new KeyValue(key, family, fields[1], ts, Type.Put, fields[1]));
+          add(new KeyValue(key, family, fields[1], ts, KeyValue.Type.Put, fields[1]));
         }
       }
     };
@@ -98,10 +99,12 @@ public class IntegrationTestImportTsv extends Configured implements Tool {
   // JUnit/Maven or by main when run from the CLI.
   protected static IntegrationTestingUtility util = null;
 
+  @Override
   public Configuration getConf() {
     return util.getConfiguration();
   }
 
+  @Override
   public void setConf(Configuration conf) {
     LOG.debug("Ignoring setConf call.");
   }
@@ -207,6 +210,7 @@ public class IntegrationTestImportTsv extends Configured implements Tool {
     LOG.info("testGenerateAndLoad completed successfully.");
   }
 
+  @Override
   public int run(String[] args) throws Exception {
     if (args.length != 0) {
       System.err.println(format("%s [genericOptions]", NAME));

hbase-it/src/test/java/org/apache/hadoop/hbase/mapreduce/IntegrationTestTableMapReduceUtil.java

@@ -88,6 +88,7 @@ public class IntegrationTestTableMapReduceUtil implements Configurable, Tool {
     return 0;
   }
 
+  @Override
   public void setConf(Configuration conf) {
     if (util != null) {
       throw new IllegalArgumentException(

hbase-it/src/test/java/org/apache/hadoop/hbase/mapreduce/IntegrationTestTableSnapshotInputFormat.java

@@ -41,11 +41,11 @@ import org.slf4j.LoggerFactory;
  * f2:(null) to be the the same as the row value.
  *
  * <pre>
- * aaa, f1: => aaa
+ * aaa, f1: =&gt; aaa
- * aaa, f2: => aaa
+ * aaa, f2: =&gt; aaa
- * aab, f1: => aab
+ * aab, f1: =&gt; aab
  * ....
- * zzz, f2: => zzz
+ * zzz, f2: =&gt; zzz
  * </pre>
  *
  * Then the test creates a snapshot from this table, and overrides the values in the original table
@@ -90,8 +90,6 @@ public class IntegrationTestTableSnapshotInputFormat extends IntegrationTestBase
   private static final byte[] MAPRED_START_ROW = Bytes.toBytes("aaa");
   private static final byte[] MAPRED_END_ROW = Bytes.toBytes("zz{"); // 'z' + 1 => '{'
 
-  private IntegrationTestingUtility util;
-
   @Override
   public void setConf(Configuration conf) {
     super.setConf(conf);

hbase-it/src/test/java/org/apache/hadoop/hbase/test/IntegrationTestBigLinkedList.java

@@ -115,6 +115,7 @@ import org.slf4j.LoggerFactory;
 
 import org.apache.hbase.thirdparty.com.google.common.base.Preconditions;
 import org.apache.hbase.thirdparty.com.google.common.collect.Sets;
+import org.apache.hbase.thirdparty.com.google.common.util.concurrent.Uninterruptibles;
 import org.apache.hbase.thirdparty.org.apache.commons.cli.CommandLine;
 import org.apache.hbase.thirdparty.org.apache.commons.cli.GnuParser;
 import org.apache.hbase.thirdparty.org.apache.commons.cli.HelpFormatter;
@@ -289,7 +290,7 @@ public class IntegrationTestBigLinkedList extends IntegrationTestBase {
      */
     public static final String BIG_FAMILY_VALUE_SIZE_KEY = "generator.big.family.value.size";
 
-    public static enum Counts {
+    public static enum GeneratorCounts {
       SUCCESS,
       TERMINATING,
       UNDEFINED,
@@ -448,6 +449,7 @@ public class IntegrationTestBigLinkedList extends IntegrationTestBase {
 
       volatile boolean walkersStop;
       int numWalkers;
+      final Object flushedLoopsLock = new Object();
       volatile List<Long> flushedLoops = new ArrayList<>();
       List<Thread> walkers = new ArrayList<>();
 
@@ -550,9 +552,9 @@ public class IntegrationTestBigLinkedList extends IntegrationTestBase {
       }
 
       private void addFlushed(byte[] rowKey) {
-        synchronized (flushedLoops) {
+        synchronized (flushedLoopsLock) {
           flushedLoops.add(Bytes.toLong(rowKey));
-          flushedLoops.notifyAll();
+          flushedLoopsLock.notifyAll();
         }
       }
 
@@ -597,16 +599,12 @@ public class IntegrationTestBigLinkedList extends IntegrationTestBase {
       }
 
       private void joinWalkers() {
-        walkersStop = true;
+        synchronized (flushedLoopsLock) {
-        synchronized (flushedLoops) {
+          walkersStop = true;
-          flushedLoops.notifyAll();
+          flushedLoopsLock.notifyAll();
         }
         for (Thread walker : walkers) {
-          try {
+          Uninterruptibles.joinUninterruptibly(walker);
-            walker.join();
-          } catch (InterruptedException e) {
-            // no-op
-          }
         }
       }
 
@@ -635,7 +633,7 @@ public class IntegrationTestBigLinkedList extends IntegrationTestBase {
               try {
                 walkLoop(node);
               } catch (IOException e) {
-                context.getCounter(Counts.IOEXCEPTION).increment(1l);
+                context.getCounter(GeneratorCounts.IOEXCEPTION).increment(1l);
                 return;
               }
             } catch (InterruptedException e) {
@@ -651,9 +649,9 @@ public class IntegrationTestBigLinkedList extends IntegrationTestBase {
         }
 
         private long selectLoop() throws InterruptedException {
-          synchronized (flushedLoops) {
+          synchronized (flushedLoopsLock) {
             while (flushedLoops.isEmpty() && !walkersStop) {
-              flushedLoops.wait();
+              flushedLoopsLock.wait();
             }
             if (walkersStop) {
               throw new InterruptedException();
@@ -691,19 +689,17 @@ public class IntegrationTestBigLinkedList extends IntegrationTestBase {
           while (numQueries < maxQueries) {
             numQueries++;
             byte[] prev = node.prev;
-            long t1 = EnvironmentEdgeManager.currentTime();
             node = getNode(prev, table, node);
-            long t2 = EnvironmentEdgeManager.currentTime();
             if (node == null) {
               LOG.error("ConcurrentWalker found UNDEFINED NODE: " + Bytes.toStringBinary(prev));
-              context.getCounter(Counts.UNDEFINED).increment(1l);
+              context.getCounter(GeneratorCounts.UNDEFINED).increment(1l);
             } else if (node.prev.length == NO_KEY.length) {
               LOG.error(
                 "ConcurrentWalker found TERMINATING NODE: " + Bytes.toStringBinary(node.key));
-              context.getCounter(Counts.TERMINATING).increment(1l);
+              context.getCounter(GeneratorCounts.TERMINATING).increment(1l);
             } else {
               // Increment for successful walk
-              context.getCounter(Counts.SUCCESS).increment(1l);
+              context.getCounter(GeneratorCounts.SUCCESS).increment(1l);
             }
           }
           table.close();
@@ -875,14 +871,17 @@ public class IntegrationTestBigLinkedList extends IntegrationTestBase {
         }
 
         if (
-          counters.findCounter(Counts.TERMINATING).getValue() > 0
+          counters.findCounter(GeneratorCounts.TERMINATING).getValue() > 0
-            || counters.findCounter(Counts.UNDEFINED).getValue() > 0
+            || counters.findCounter(GeneratorCounts.UNDEFINED).getValue() > 0
-            || counters.findCounter(Counts.IOEXCEPTION).getValue() > 0
+            || counters.findCounter(GeneratorCounts.IOEXCEPTION).getValue() > 0
         ) {
           LOG.error("Concurrent walker failed to verify during Generation phase");
-          LOG.error("TERMINATING nodes: " + counters.findCounter(Counts.TERMINATING).getValue());
+          LOG.error(
-          LOG.error("UNDEFINED nodes: " + counters.findCounter(Counts.UNDEFINED).getValue());
+            "TERMINATING nodes: " + counters.findCounter(GeneratorCounts.TERMINATING).getValue());
-          LOG.error("IOEXCEPTION nodes: " + counters.findCounter(Counts.IOEXCEPTION).getValue());
+          LOG.error(
+            "UNDEFINED nodes: " + counters.findCounter(GeneratorCounts.UNDEFINED).getValue());
+          LOG.error(
+            "IOEXCEPTION nodes: " + counters.findCounter(GeneratorCounts.IOEXCEPTION).getValue());
           return false;
         }
       } catch (IOException e) {
@@ -1033,16 +1032,17 @@ public class IntegrationTestBigLinkedList extends IntegrationTestBase {
           LocatedFileStatus keyFileStatus = iterator.next();
           // Skip "_SUCCESS" file.
           if (keyFileStatus.getPath().getName().startsWith("_")) continue;
-          result.addAll(readFileToSearch(conf, fs, keyFileStatus));
+          result.addAll(readFileToSearch(conf, keyFileStatus));
         }
       }
       return result;
     }
 
-    private static SortedSet<byte[]> readFileToSearch(final Configuration conf, final FileSystem fs,
+    private static SortedSet<byte[]> readFileToSearch(final Configuration conf,
       final LocatedFileStatus keyFileStatus) throws IOException, InterruptedException {
       SortedSet<byte[]> result = new TreeSet<>(Bytes.BYTES_COMPARATOR);
-      // Return entries that are flagged Counts.UNDEFINED in the value. Return the row. This is
+      // Return entries that are flagged VerifyCounts.UNDEFINED in the value. Return the row. This
+      // is
       // what is missing.
       TaskAttemptContext context = new TaskAttemptContextImpl(conf, new TaskAttemptID());
       try (SequenceFileAsBinaryInputFormat.SequenceFileAsBinaryRecordReader rr =
@@ -1053,7 +1053,7 @@ public class IntegrationTestBigLinkedList extends IntegrationTestBase {
         while (rr.nextKeyValue()) {
           rr.getCurrentKey();
           BytesWritable bw = rr.getCurrentValue();
-          if (Verify.VerifyReducer.whichType(bw.getBytes()) == Verify.Counts.UNDEFINED) {
+          if (Verify.VerifyReducer.whichType(bw.getBytes()) == Verify.VerifyCounts.UNDEFINED) {
             byte[] key = new byte[rr.getCurrentKey().getLength()];
             System.arraycopy(rr.getCurrentKey().getBytes(), 0, key, 0,
               rr.getCurrentKey().getLength());
@@ -1114,7 +1114,7 @@ public class IntegrationTestBigLinkedList extends IntegrationTestBase {
      * Don't change the order of these enums. Their ordinals are used as type flag when we emit
      * problems found from the reducer.
      */
-    public static enum Counts {
+    public static enum VerifyCounts {
       UNREFERENCED,
       UNDEFINED,
       REFERENCED,
@@ -1133,9 +1133,9 @@ public class IntegrationTestBigLinkedList extends IntegrationTestBase {
       extends Reducer<BytesWritable, BytesWritable, BytesWritable, BytesWritable> {
       private ArrayList<byte[]> refs = new ArrayList<>();
       private final BytesWritable UNREF =
-        new BytesWritable(addPrefixFlag(Counts.UNREFERENCED.ordinal(), new byte[] {}));
+        new BytesWritable(addPrefixFlag(VerifyCounts.UNREFERENCED.ordinal(), new byte[] {}));
       private final BytesWritable LOSTFAM =
-        new BytesWritable(addPrefixFlag(Counts.LOST_FAMILIES.ordinal(), new byte[] {}));
+        new BytesWritable(addPrefixFlag(VerifyCounts.LOST_FAMILIES.ordinal(), new byte[] {}));
 
       private AtomicInteger rows = new AtomicInteger(0);
       private Connection connection;
@@ -1177,9 +1177,9 @@ public class IntegrationTestBigLinkedList extends IntegrationTestBase {
        * n * @return Type from the Counts enum of this row. Reads prefix added by
        * {@link #addPrefixFlag(int, byte[])}
        */
-      public static Counts whichType(final byte[] bs) {
+      public static VerifyCounts whichType(final byte[] bs) {
         int ordinal = Bytes.toShort(bs, 0, Bytes.SIZEOF_SHORT);
-        return Counts.values()[ordinal];
+        return VerifyCounts.values()[ordinal];
       }
 
       /**
@@ -1221,7 +1221,7 @@ public class IntegrationTestBigLinkedList extends IntegrationTestBase {
         if (lostFamilies) {
           String keyString = Bytes.toStringBinary(key.getBytes(), 0, key.getLength());
           LOG.error("LinkedListError: key=" + keyString + ", lost big or tiny families");
-          context.getCounter(Counts.LOST_FAMILIES).increment(1);
+          context.getCounter(VerifyCounts.LOST_FAMILIES).increment(1);
           context.write(key, LOSTFAM);
         }
 
@@ -1233,11 +1233,11 @@ public class IntegrationTestBigLinkedList extends IntegrationTestBase {
             byte[] bs = refs.get(i);
             int ordinal;
             if (i <= 0) {
-              ordinal = Counts.UNDEFINED.ordinal();
+              ordinal = VerifyCounts.UNDEFINED.ordinal();
               context.write(key, new BytesWritable(addPrefixFlag(ordinal, bs)));
-              context.getCounter(Counts.UNDEFINED).increment(1);
+              context.getCounter(VerifyCounts.UNDEFINED).increment(1);
             } else {
-              ordinal = Counts.EXTRA_UNDEF_REFERENCES.ordinal();
+              ordinal = VerifyCounts.EXTRA_UNDEF_REFERENCES.ordinal();
               context.write(key, new BytesWritable(addPrefixFlag(ordinal, bs)));
             }
           }
@@ -1252,7 +1252,7 @@ public class IntegrationTestBigLinkedList extends IntegrationTestBase {
         } else if (defCount > 0 && refs.isEmpty()) {
           // node is defined but not referenced
           context.write(key, UNREF);
-          context.getCounter(Counts.UNREFERENCED).increment(1);
+          context.getCounter(VerifyCounts.UNREFERENCED).increment(1);
           if (rows.addAndGet(1) < MISSING_ROWS_TO_LOG) {
             String keyString = Bytes.toStringBinary(key.getBytes(), 0, key.getLength());
             context.getCounter("unref", keyString).increment(1);
@@ -1261,13 +1261,13 @@ public class IntegrationTestBigLinkedList extends IntegrationTestBase {
           if (refs.size() > 1) {
             // Skip first reference.
             for (int i = 1; i < refs.size(); i++) {
-              context.write(key,
+              context.write(key, new BytesWritable(
-                new BytesWritable(addPrefixFlag(Counts.EXTRAREFERENCES.ordinal(), refs.get(i))));
+                addPrefixFlag(VerifyCounts.EXTRAREFERENCES.ordinal(), refs.get(i))));
             }
-            context.getCounter(Counts.EXTRAREFERENCES).increment(refs.size() - 1);
+            context.getCounter(VerifyCounts.EXTRAREFERENCES).increment(refs.size() - 1);
           }
           // node is defined and referenced
-          context.getCounter(Counts.REFERENCED).increment(1);
+          context.getCounter(VerifyCounts.REFERENCED).increment(1);
         }
       }
 
@@ -1275,6 +1275,7 @@ public class IntegrationTestBigLinkedList extends IntegrationTestBase {
        * Dump out extra info around references if there are any. Helps debugging.
        * @return StringBuilder filled with references if any. n
        */
+      @SuppressWarnings("JavaUtilDate")
       private StringBuilder dumpExtraInfoOnRefs(final BytesWritable key, final Context context,
         final List<byte[]> refs) throws IOException {
         StringBuilder refsSb = null;
@@ -1429,8 +1430,8 @@ public class IntegrationTestBigLinkedList extends IntegrationTestBase {
      * @return True if the values match what's expected, false otherwise
      */
     protected boolean verifyExpectedValues(long expectedReferenced, Counters counters) {
-      final Counter referenced = counters.findCounter(Counts.REFERENCED);
+      final Counter referenced = counters.findCounter(VerifyCounts.REFERENCED);
-      final Counter unreferenced = counters.findCounter(Counts.UNREFERENCED);
+      final Counter unreferenced = counters.findCounter(VerifyCounts.UNREFERENCED);
       boolean success = true;
 
       if (expectedReferenced != referenced.getValue()) {
@@ -1440,7 +1441,7 @@ public class IntegrationTestBigLinkedList extends IntegrationTestBase {
       }
 
       if (unreferenced.getValue() > 0) {
-        final Counter multiref = counters.findCounter(Counts.EXTRAREFERENCES);
+        final Counter multiref = counters.findCounter(VerifyCounts.EXTRAREFERENCES);
         boolean couldBeMultiRef = (multiref.getValue() == unreferenced.getValue());
         LOG.error(
           "Unreferenced nodes were not expected. Unreferenced count=" + unreferenced.getValue()
@@ -1457,8 +1458,8 @@ public class IntegrationTestBigLinkedList extends IntegrationTestBase {
      * @return True if the "bad" counter objects are 0, false otherwise
      */
     protected boolean verifyUnexpectedValues(Counters counters) {
-      final Counter undefined = counters.findCounter(Counts.UNDEFINED);
+      final Counter undefined = counters.findCounter(VerifyCounts.UNDEFINED);
-      final Counter lostfamilies = counters.findCounter(Counts.LOST_FAMILIES);
+      final Counter lostfamilies = counters.findCounter(VerifyCounts.LOST_FAMILIES);
       boolean success = true;
 
       if (undefined.getValue() > 0) {
@@ -1839,8 +1840,6 @@ public class IntegrationTestBigLinkedList extends IntegrationTestBase {
     return node;
   }
 
-  protected IntegrationTestingUtility util;
-
   @Override
   public void setUpCluster() throws Exception {
     util = getTestingUtil(getConf());

hbase-it/src/test/java/org/apache/hadoop/hbase/test/IntegrationTestBigLinkedListWithVisibility.java

@@ -71,6 +71,7 @@ import org.junit.experimental.categories.Category;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import org.apache.hbase.thirdparty.com.google.common.base.Splitter;
 import org.apache.hbase.thirdparty.org.apache.commons.cli.CommandLine;
 
 /**
@@ -204,7 +205,7 @@ public class IntegrationTestBigLinkedListWithVisibility extends IntegrationTestB
       protected void persist(org.apache.hadoop.mapreduce.Mapper.Context output, long count,
         byte[][] prev, byte[][] current, byte[] id) throws IOException {
         String visibilityExps = "";
-        String[] split = labels.split(COMMA);
+        String[] split = Splitter.on(COMMA).splitToStream(labels).toArray(String[]::new);
         for (int i = 0; i < current.length; i++) {
           for (int j = 0; j < DEFAULT_TABLES_COUNT; j++) {
             Put put = new Put(current[i]);
@@ -248,18 +249,16 @@ public class IntegrationTestBigLinkedListWithVisibility extends IntegrationTestB
     }
 
     public int runCopier(String outputDir) throws Exception {
-      Job job = null;
+      Job job = new Job(getConf());
-      Scan scan = null;
-      job = new Job(getConf());
       job.setJobName("Data copier");
       job.getConfiguration().setInt("INDEX", labelIndex);
       job.getConfiguration().set("LABELS", labels);
       job.setJarByClass(getClass());
-      scan = new Scan();
+      Scan scan = new Scan();
       scan.setCacheBlocks(false);
       scan.setRaw(true);
 
-      String[] split = labels.split(COMMA);
+      String[] split = Splitter.on(COMMA).splitToStream(labels).toArray(String[]::new);
       scan.setAuthorizations(
         new Authorizations(split[this.labelIndex * 2], split[(this.labelIndex * 2) + 1]));
       if (delete) {
@@ -424,7 +423,7 @@ public class IntegrationTestBigLinkedListWithVisibility extends IntegrationTestB
       scan.addColumn(FAMILY_NAME, COLUMN_PREV);
       scan.setCaching(10000);
       scan.setCacheBlocks(false);
-      String[] split = labels.split(COMMA);
+      String[] split = Splitter.on(COMMA).splitToStream(labels).toArray(String[]::new);
 
       scan.setAuthorizations(
         new Authorizations(split[this.labelIndex * 2], split[(this.labelIndex * 2) + 1]));
@@ -470,7 +469,6 @@ public class IntegrationTestBigLinkedListWithVisibility extends IntegrationTestB
   static class VisibilityLoop extends Loop {
     private static final int SLEEP_IN_MS = 5000;
     private static final Logger LOG = LoggerFactory.getLogger(VisibilityLoop.class);
-    IntegrationTestBigLinkedListWithVisibility it;
 
     @Override
     protected void runGenerator(int numMappers, long numNodes, String outputDir, Integer width,
@@ -652,10 +650,6 @@ public class IntegrationTestBigLinkedListWithVisibility extends IntegrationTestB
 
   @Override
   public int runTestFromCommandLine() throws Exception {
-    Tool tool = null;
+    return ToolRunner.run(getConf(), new VisibilityLoop(), otherArgs);
-    Loop loop = new VisibilityLoop();
-    loop.it = this;
-    tool = loop;
-    return ToolRunner.run(getConf(), tool, otherArgs);
   }
 }

hbase-it/src/test/java/org/apache/hadoop/hbase/test/IntegrationTestLoadAndVerify.java

@@ -26,6 +26,8 @@ import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.io.InterruptedIOException;
+import java.nio.charset.StandardCharsets;
+import java.util.List;
 import java.util.Random;
 import java.util.Set;
 import java.util.SortedSet;
@@ -85,6 +87,8 @@ import org.junit.experimental.categories.Category;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import org.apache.hbase.thirdparty.com.google.common.base.Splitter;
+import org.apache.hbase.thirdparty.com.google.common.collect.Iterables;
 import org.apache.hbase.thirdparty.com.google.common.collect.Sets;
 import org.apache.hbase.thirdparty.org.apache.commons.cli.CommandLine;
 
@@ -441,34 +445,32 @@ public class IntegrationTestLoadAndVerify extends IntegrationTestBase {
     }
     if (!fs.isDirectory(keysInputDir)) {
       FileStatus keyFileStatus = fs.getFileStatus(keysInputDir);
-      readFileToSearch(conf, fs, keyFileStatus, result);
+      readFileToSearch(fs, keyFileStatus, result);
     } else {
       RemoteIterator<LocatedFileStatus> iterator = fs.listFiles(keysInputDir, false);
       while (iterator.hasNext()) {
         LocatedFileStatus keyFileStatus = iterator.next();
         // Skip "_SUCCESS" file.
         if (keyFileStatus.getPath().getName().startsWith("_")) continue;
-        readFileToSearch(conf, fs, keyFileStatus, result);
+        readFileToSearch(fs, keyFileStatus, result);
       }
     }
     return result;
   }
 
-  private static SortedSet<byte[]> readFileToSearch(final Configuration conf, final FileSystem fs,
+  private static SortedSet<byte[]> readFileToSearch(final FileSystem fs,
     final FileStatus keyFileStatus, SortedSet<byte[]> result)
     throws IOException, InterruptedException {
     // verify uses file output format and writes <Text, Text>. We can read it as a text file
-    try (InputStream in = fs.open(keyFileStatus.getPath());
+    try (InputStream in = fs.open(keyFileStatus.getPath()); BufferedReader reader =
-      BufferedReader reader = new BufferedReader(new InputStreamReader(in))) {
+      new BufferedReader(new InputStreamReader(in, StandardCharsets.UTF_8))) {
       // extract out the key and return that missing as a missing key
       String line;
       while ((line = reader.readLine()) != null) {
         if (line.isEmpty()) continue;
-
+        List<String> parts = Splitter.onPattern("\\s+").splitToList(line);
-        String[] parts = line.split("\\s+");
+        if (parts.size() >= 1) {
-        if (parts.length >= 1) {
+          result.add(Bytes.toBytesBinary(Iterables.get(parts, 0)));
-          String key = parts[0];
-          result.add(Bytes.toBytesBinary(key));
         } else {
           LOG.info("Cannot parse key from: " + line);
         }
@@ -477,7 +479,7 @@ public class IntegrationTestLoadAndVerify extends IntegrationTestBase {
     return result;
   }
 
-  private int doSearch(Configuration conf, String keysDir) throws Exception {
+  private int doSearch(String keysDir) throws Exception {
     Path inputDir = new Path(keysDir);
 
     getConf().set(SEARCHER_INPUTDIR_KEY, inputDir.toString());
@@ -618,7 +620,7 @@ public class IntegrationTestLoadAndVerify extends IntegrationTestBase {
       }
     }
     if (doSearch) {
-      return doSearch(getConf(), keysDir);
+      return doSearch(keysDir);
     }
     return 0;
   }

hbase-it/src/test/java/org/apache/hadoop/hbase/test/IntegrationTestLoadCommonCrawl.java

@@ -98,6 +98,7 @@ import org.apache.hadoop.util.ToolRunner;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import org.apache.hbase.thirdparty.com.google.common.base.Splitter;
 import org.apache.hbase.thirdparty.org.apache.commons.cli.CommandLine;
 
 /**
@@ -220,12 +221,11 @@ public class IntegrationTestLoadCommonCrawl extends IntegrationTestBase {
         LOG.error("Loader failed");
         return -1;
       }
-      res = runVerify(outputDir);
+      return runVerify(outputDir);
     } catch (Exception e) {
       LOG.error("Tool failed with exception", e);
       return -1;
     }
-    return 0;
   }
 
   @Override
@@ -527,9 +527,9 @@ public class IntegrationTestLoadCommonCrawl extends IntegrationTestBase {
         try (FSDataInputStream is = fs.open(warcFileInput)) {
           InputStreamReader reader;
           if (warcFileInput.getName().toLowerCase().endsWith(".gz")) {
-            reader = new InputStreamReader(new GZIPInputStream(is));
+            reader = new InputStreamReader(new GZIPInputStream(is), StandardCharsets.UTF_8);
           } else {
-            reader = new InputStreamReader(is);
+            reader = new InputStreamReader(is, StandardCharsets.UTF_8);
           }
           try (BufferedReader br = new BufferedReader(reader)) {
             String line;
@@ -949,8 +949,9 @@ public class IntegrationTestLoadCommonCrawl extends IntegrationTestBase {
     // Reverse the components of the hostname
     String reversedHost;
     if (uri.getHost() != null) {
+      final String[] hostComponents =
+        Splitter.on('.').splitToStream(uri.getHost()).toArray(String[]::new);
       final StringBuilder sb = new StringBuilder();
-      final String[] hostComponents = uri.getHost().split("\\.");
       for (int i = hostComponents.length - 1; i >= 0; i--) {
         sb.append(hostComponents[i]);
         if (i != 0) {

hbase-it/src/test/java/org/apache/hadoop/hbase/test/IntegrationTestReplication.java

@@ -19,6 +19,7 @@ package org.apache.hadoop.hbase.test;
 
 import java.util.Collections;
 import java.util.HashMap;
+import java.util.Iterator;
 import java.util.List;
 import java.util.Set;
 import java.util.TreeSet;
@@ -43,6 +44,7 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import org.apache.hbase.thirdparty.com.google.common.base.Joiner;
+import org.apache.hbase.thirdparty.com.google.common.base.Splitter;
 import org.apache.hbase.thirdparty.org.apache.commons.cli.CommandLine;
 
 /**
@@ -109,7 +111,7 @@ public class IntegrationTestReplication extends IntegrationTestBigLinkedList {
    * Wrapper around an HBase ClusterID allowing us to get admin connections and configurations for
    * it
    */
-  protected class ClusterID {
+  protected static class ClusterID {
     private final Configuration configuration;
     private Connection connection = null;
 
@@ -121,10 +123,10 @@ public class IntegrationTestReplication extends IntegrationTestBigLinkedList {
      */
     public ClusterID(Configuration base, String key) {
       configuration = new Configuration(base);
-      String[] parts = key.split(":");
+      Iterator<String> iter = Splitter.on(':').split(key).iterator();
-      configuration.set(HConstants.ZOOKEEPER_QUORUM, parts[0]);
+      configuration.set(HConstants.ZOOKEEPER_QUORUM, iter.next());
-      configuration.set(HConstants.ZOOKEEPER_CLIENT_PORT, parts[1]);
+      configuration.set(HConstants.ZOOKEEPER_CLIENT_PORT, iter.next());
-      configuration.set(HConstants.ZOOKEEPER_ZNODE_PARENT, parts[2]);
+      configuration.set(HConstants.ZOOKEEPER_ZNODE_PARENT, iter.next());
     }
 
     @Override
@@ -150,8 +152,20 @@ public class IntegrationTestReplication extends IntegrationTestBigLinkedList {
       this.connection = null;
     }
 
-    public boolean equals(ClusterID other) {
+    @Override
-      return this.toString().equalsIgnoreCase(other.toString());
+    public boolean equals(Object other) {
+      if (this == other) {
+        return true;
+      }
+      if (!(other instanceof ClusterID)) {
+        return false;
+      }
+      return toString().equalsIgnoreCase(other.toString());
+    }
+
+    @Override
+    public int hashCode() {
+      return toString().hashCode();
     }
   }
 
@@ -306,7 +320,7 @@ public class IntegrationTestReplication extends IntegrationTestBigLinkedList {
       if (!noReplicationSetup) {
         setupTablesAndReplication();
       }
-      int expectedNumNodes = 0;
+      long expectedNumNodes = 0;
       for (int i = 0; i < numIterations; i++) {
         LOG.info("Starting iteration = " + i);
 

hbase-it/src/test/java/org/apache/hadoop/hbase/test/IntegrationTestTimeBoundedRequestsWithRegionReplicas.java

@@ -267,7 +267,8 @@ public class IntegrationTestTimeBoundedRequestsWithRegionReplicas extends Integr
       try {
         this.timeoutThread.join();
       } catch (InterruptedException e) {
-        e.printStackTrace();
+        // Restore interrupt status
+        Thread.currentThread().interrupt();
       }
       this.aborted = true;
       super.waitForFinish();
@@ -293,7 +294,7 @@ public class IntegrationTestTimeBoundedRequestsWithRegionReplicas extends Integr
       return new TimeBoundedMultiThreadedReaderThread(readerId);
     }
 
-    private class TimeoutThread extends Thread {
+    private static class TimeoutThread extends Thread {
       long timeout;
       long reportInterval = 60000;
 

hbase-it/src/test/java/org/apache/hadoop/hbase/test/IntegrationTestWithCellVisibilityLoadAndVerify.java

@@ -59,6 +59,8 @@ import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
 import org.apache.hadoop.util.ToolRunner;
 import org.junit.experimental.categories.Category;
 
+import org.apache.hbase.thirdparty.com.google.common.base.Splitter;
+import org.apache.hbase.thirdparty.com.google.common.collect.Iterables;
 import org.apache.hbase.thirdparty.org.apache.commons.cli.CommandLine;
 
 /**
@@ -119,14 +121,16 @@ public class IntegrationTestWithCellVisibilityLoadAndVerify extends IntegrationT
     conf.set("hbase.superuser", User.getCurrent().getName());
     conf.setBoolean("dfs.permissions", false);
     super.setUpCluster();
-    String[] users = userNames.split(",");
+    List<String> users = Splitter.on(',').splitToList(userNames);
-    if (users.length != 2) {
+    if (users.size() != 2) {
       System.err.println(ERROR_STR);
       throw new IOException(ERROR_STR);
     }
-    System.out.println(userNames + " " + users[0] + " " + users[1]);
+    String user1 = Iterables.get(users, 0);
-    USER1 = User.createUserForTesting(conf, users[0], new String[] {});
+    String user2 = Iterables.get(users, 1);
-    USER2 = User.createUserForTesting(conf, users[1], new String[] {});
+    System.out.println(userNames + " " + user1 + " " + user2);
+    USER1 = User.createUserForTesting(conf, user1, new String[] {});
+    USER2 = User.createUserForTesting(conf, user2, new String[] {});
     addLabelsAndAuths();
   }
 

hbase-it/src/test/java/org/apache/hadoop/hbase/trace/IntegrationTestSendTraceRequests.java

@@ -28,6 +28,7 @@ import java.util.concurrent.Executors;
 import java.util.concurrent.LinkedBlockingQueue;
 import java.util.concurrent.ThreadLocalRandom;
 import java.util.concurrent.TimeUnit;
+import org.apache.commons.io.IOUtils;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.hbase.HBaseConfiguration;
 import org.apache.hadoop.hbase.IntegrationTestingUtility;
@@ -137,11 +138,9 @@ public class IntegrationTestSendTraceRequests extends AbstractHBaseTool {
 
             ht.close();
             ht = null;
-          } catch (IOException e) {
+          } catch (Exception e) {
-            e.printStackTrace();
             span.addEvent("exception",
               Attributes.of(AttributeKey.stringKey("exception"), e.getClass().getSimpleName()));
-          } catch (Exception e) {
           } finally {
             span.end();
             if (rs != null) {
@@ -162,36 +161,36 @@ public class IntegrationTestSendTraceRequests extends AbstractHBaseTool {
 
         @Override
         public void run() {
-
           Table ht = null;
           try {
             ht = util.getConnection().getTable(tableName);
+            long accum = 0;
+            for (int x = 0; x < 5; x++) {
+              Span span = TraceUtil.getGlobalTracer().spanBuilder("gets").startSpan();
+              try (Scope scope = span.makeCurrent()) {
+                long rk = rowKeyQueue.take();
+                Result r1 = ht.get(new Get(Bytes.toBytes(rk)));
+                if (r1 != null) {
+                  accum |= Bytes.toLong(r1.getRow());
+                }
+                Result r2 = ht.get(new Get(Bytes.toBytes(rk)));
+                if (r2 != null) {
+                  accum |= Bytes.toLong(r2.getRow());
+                }
+                span.addEvent("Accum = " + accum);
+              } catch (IOException | InterruptedException ie) {
+                // IGNORED
+              } finally {
+                span.end();
+              }
+            }
           } catch (IOException e) {
-            e.printStackTrace();
+            // IGNORED
-          }
+          } finally {
-
+            if (ht != null) {
-          long accum = 0;
+              IOUtils.closeQuietly(ht);
-          for (int x = 0; x < 5; x++) {
-            Span span = TraceUtil.getGlobalTracer().spanBuilder("gets").startSpan();
-            try (Scope scope = span.makeCurrent()) {
-              long rk = rowKeyQueue.take();
-              Result r1 = ht.get(new Get(Bytes.toBytes(rk)));
-              if (r1 != null) {
-                accum |= Bytes.toLong(r1.getRow());
-              }
-              Result r2 = ht.get(new Get(Bytes.toBytes(rk)));
-              if (r2 != null) {
-                accum |= Bytes.toLong(r2.getRow());
-              }
-              span.addEvent("Accum = " + accum);
-
-            } catch (IOException | InterruptedException ie) {
-              // IGNORED
-            } finally {
-              span.end();
             }
           }
-
         }
       };
       service.execute(runnable);