diff --git a/src/main/java/com/linkedin/xinfra/monitor/XinfraMonitor.java b/src/main/java/com/linkedin/xinfra/monitor/XinfraMonitor.java
index d516b076..d59486b8 100644
--- a/src/main/java/com/linkedin/xinfra/monitor/XinfraMonitor.java
+++ b/src/main/java/com/linkedin/xinfra/monitor/XinfraMonitor.java
@@ -16,7 +16,6 @@
 import com.linkedin.xinfra.monitor.services.ServiceFactory;
 import java.io.BufferedReader;
 import java.io.FileReader;
-import java.lang.reflect.Constructor;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
@@ -60,11 +59,11 @@ public class XinfraMonitor {
    */
 
   @SuppressWarnings({"rawtypes"})
-  public XinfraMonitor(Map<String, Map> allClusterProps) throws Exception {
+  public XinfraMonitor(Map<String, Map<String, Object>> allClusterProps) throws Exception {
     _apps = new ConcurrentHashMap<>();
     _services = new ConcurrentHashMap<>();
 
-    for (Map.Entry<String, Map> clusterProperty : allClusterProps.entrySet()) {
+    for (Map.Entry<String, Map<String, Object>> clusterProperty : allClusterProps.entrySet()) {
       String clusterName = clusterProperty.getKey();
       Map props = clusterProperty.getValue();
       if (!props.containsKey(XinfraMonitorConstants.CLASS_NAME_CONFIG))
@@ -94,15 +93,6 @@ public XinfraMonitor(Map<String, Map> allClusterProps) throws Exception {
       (config, now) -> _offlineRunnables.size());
   }
 
-  private boolean constructorContainsClass(Constructor<?>[] constructors, Class<?> classObject) {
-    for (int n = 0; n < constructors[0].getParameterTypes().length; ++n) {
-      if (constructors[0].getParameterTypes()[n].equals(classObject)) {
-        return true;
-      }
-    }
-    return false;
-  }
-
   public synchronized void start() throws Exception {
     if (!_isRunning.compareAndSet(false, true)) {
       return;
@@ -165,7 +155,6 @@ public void awaitShutdown() {
       service.awaitShutdown(Integer.MAX_VALUE, TimeUnit.MILLISECONDS);
   }
 
-  @SuppressWarnings("rawtypes")
   public static void main(String[] args) throws Exception {
     if (args.length <= 0) {
       LOG.info("USAGE: java [options] " + XinfraMonitor.class.getName() + " config/xinfra-monitor.properties");
@@ -182,7 +171,7 @@ public static void main(String[] args) throws Exception {
     }
 
     @SuppressWarnings("unchecked")
-    Map<String, Map> props = new ObjectMapper().readValue(buffer.toString(), Map.class);
+    Map<String, Map<String, Object>> props = new ObjectMapper().readValue(buffer.toString(), Map.class);
     XinfraMonitor xinfraMonitor = new XinfraMonitor(props);
     xinfraMonitor.start();
     LOG.info("Xinfra Monitor has started.");
diff --git a/src/main/java/com/linkedin/xinfra/monitor/XinfraMonitorConstants.java b/src/main/java/com/linkedin/xinfra/monitor/XinfraMonitorConstants.java
index f22c63c9..9db078b9 100644
--- a/src/main/java/com/linkedin/xinfra/monitor/XinfraMonitorConstants.java
+++ b/src/main/java/com/linkedin/xinfra/monitor/XinfraMonitorConstants.java
@@ -15,9 +15,7 @@
  */
 public class XinfraMonitorConstants {
 
-  public XinfraMonitorConstants() {
-    
-  }
+  private XinfraMonitorConstants() {}
 
   public static final String TAGS_NAME = "name";
 
diff --git a/src/main/java/com/linkedin/xinfra/monitor/apps/SingleClusterMonitor.java b/src/main/java/com/linkedin/xinfra/monitor/apps/SingleClusterMonitor.java
index a44b0827..ccac7e9d 100644
--- a/src/main/java/com/linkedin/xinfra/monitor/apps/SingleClusterMonitor.java
+++ b/src/main/java/com/linkedin/xinfra/monitor/apps/SingleClusterMonitor.java
@@ -24,6 +24,8 @@
 import com.linkedin.xinfra.monitor.services.configs.ProduceServiceConfig;
 import com.linkedin.xinfra.monitor.services.configs.TopicManagementServiceConfig;
 import com.linkedin.xinfra.monitor.services.metrics.ClusterTopicManipulationMetrics;
+
+import java.time.Duration;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.HashMap;
@@ -39,6 +41,7 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import static com.linkedin.xinfra.monitor.common.Utils.delay;
 import static com.linkedin.xinfra.monitor.common.Utils.prettyPrint;
 
 /*
@@ -94,14 +97,9 @@ public void start() throws Exception {
       _topicManagementService.start();
       CompletableFuture<Void> topicPartitionResult = _topicManagementService.topicPartitionResult();
 
-      try {
       /* Delay 2 second to reduce the chance that produce and consumer thread has race condition
       with TopicManagementService and MultiClusterTopicManagementService */
-        long threadSleepMs = TimeUnit.SECONDS.toMillis(2);
-        Thread.sleep(threadSleepMs);
-      } catch (InterruptedException e) {
-        throw new Exception("Interrupted while sleeping the thread", e);
-      }
+      delay(Duration.ofSeconds(2));
       CompletableFuture<Void> topicPartitionFuture = topicPartitionResult.thenRun(() -> {
         for (Service service : _allServices) {
           if (!service.isRunning()) {
diff --git a/src/main/java/com/linkedin/xinfra/monitor/common/Utils.java b/src/main/java/com/linkedin/xinfra/monitor/common/Utils.java
index d920437d..ce2988ed 100644
--- a/src/main/java/com/linkedin/xinfra/monitor/common/Utils.java
+++ b/src/main/java/com/linkedin/xinfra/monitor/common/Utils.java
@@ -55,8 +55,6 @@
  */
 public class Utils {
   private static final Logger LOG = LoggerFactory.getLogger(Utils.class);
-  public static final int ZK_CONNECTION_TIMEOUT_MS = 30_000;
-  public static final int ZK_SESSION_TIMEOUT_MS = 30_000;
   private static final long LIST_PARTITION_REASSIGNMENTS_TIMEOUT_MS = 60000L;
   private static final int LIST_PARTITION_REASSIGNMENTS_MAX_ATTEMPTS = 3;
   private static final String LIST_PARTITION_REASSIGNMENTS_TIMEOUT_MS_CONFIG = "list.partition.reassignment.timeout.ms";
@@ -117,9 +115,7 @@ public static List<Integer> replicaIdentifiers(Set<BrokerMetadata> brokers) {
     Collections.shuffle(brokerMetadataList);
 
     // Get broker ids for replica list
-    List<Integer> replicaList = brokerMetadataList.stream().map(m -> m.id()).collect(Collectors.toList());
-
-    return replicaList;
+    return brokerMetadataList.stream().map(m -> m.id()).collect(Collectors.toList());
   }
 
   /**
diff --git a/src/main/java/com/linkedin/xinfra/monitor/consumer/NewConsumer.java b/src/main/java/com/linkedin/xinfra/monitor/consumer/NewConsumer.java
index e958d43c..17059b44 100644
--- a/src/main/java/com/linkedin/xinfra/monitor/consumer/NewConsumer.java
+++ b/src/main/java/com/linkedin/xinfra/monitor/consumer/NewConsumer.java
@@ -85,7 +85,7 @@ public void commitAsync(OffsetCommitCallback callback) {
 
   @Override
   public OffsetAndMetadata committed(TopicPartition tp) {
-    return _consumer.committed(tp);
+    return _consumer.committed(Collections.singleton(tp)).get(tp);
   }
 
   @Override
diff --git a/src/main/java/com/linkedin/xinfra/monitor/services/ClusterTopicManipulationService.java b/src/main/java/com/linkedin/xinfra/monitor/services/ClusterTopicManipulationService.java
index 56c3ddc2..549cbed3 100644
--- a/src/main/java/com/linkedin/xinfra/monitor/services/ClusterTopicManipulationService.java
+++ b/src/main/java/com/linkedin/xinfra/monitor/services/ClusterTopicManipulationService.java
@@ -67,7 +67,6 @@ public class ClusterTopicManipulationService implements Service {
 
   private final ClusterTopicManipulationMetrics _clusterTopicManipulationMetrics;
   private final TopicFactory _topicFactory;
-  private final String _zkConnect;
 
   public ClusterTopicManipulationService(String name, AdminClient adminClient, Map<String, Object> props)
       throws ClassNotFoundException, NoSuchMethodException, IllegalAccessException, InvocationTargetException,
@@ -96,7 +95,6 @@ public ClusterTopicManipulationService(String name, AdminClient adminClient, Map
             TopicManagementServiceConfig.TOPIC_FACTORY_PROPS_CONFIG) : new HashMap();
 
     _clusterTopicManipulationMetrics = new ClusterTopicManipulationMetrics(metrics, tags);
-    _zkConnect = config.getString(TopicManagementServiceConfig.ZOOKEEPER_CONNECT_CONFIG);
     _topicFactory =
         (TopicFactory) Class.forName(topicFactoryClassName).getConstructor(Map.class).newInstance(topicFactoryConfig);
   }
diff --git a/src/main/java/com/linkedin/xinfra/monitor/services/ConsumeService.java b/src/main/java/com/linkedin/xinfra/monitor/services/ConsumeService.java
index 63caff1c..81448776 100644
--- a/src/main/java/com/linkedin/xinfra/monitor/services/ConsumeService.java
+++ b/src/main/java/com/linkedin/xinfra/monitor/services/ConsumeService.java
@@ -29,10 +29,8 @@
 import org.apache.avro.generic.GenericRecord;
 import org.apache.kafka.clients.admin.AdminClient;
 import org.apache.kafka.clients.admin.TopicDescription;
-import org.apache.kafka.clients.consumer.OffsetAndMetadata;
 import org.apache.kafka.clients.consumer.OffsetCommitCallback;
 import org.apache.kafka.common.MetricName;
-import org.apache.kafka.common.TopicPartition;
 import org.apache.kafka.common.metrics.JmxReporter;
 import org.apache.kafka.common.metrics.MetricConfig;
 import org.apache.kafka.common.metrics.Metrics;
@@ -117,9 +115,9 @@ public ConsumeService(String name,
     topicPartitionFuture.get();
   }
 
-  private void consume() throws Exception {
+  private void consume()  {
     /* Delay 1 second to reduce the chance that consumer creates topic before TopicManagementService */
-    Thread.sleep(1000);
+    Utils.delay(Duration.ofSeconds(1));
 
     Map<Integer, Long> nextIndexes = new HashMap<>();
 
@@ -132,7 +130,7 @@ record = _baseConsumer.receive();
         LOG.warn(_name + "/ConsumeService failed to receive record", e);
         /* Avoid busy while loop */
         //noinspection BusyWait
-        Thread.sleep(CONSUME_THREAD_SLEEP_MS);
+        Utils.delay(Duration.ofMillis(CONSUME_THREAD_SLEEP_MS));
         continue;
       }
 
@@ -152,16 +150,13 @@ record = _baseConsumer.receive();
       int partition = record.partition();
       /* Commit availability and commit latency service */
       /* Call commitAsync, wait for a NON-NULL return value (see https://issues.apache.org/jira/browse/KAFKA-6183) */
-      OffsetCommitCallback commitCallback = new OffsetCommitCallback() {
-        @Override
-        public void onComplete(Map<TopicPartition, OffsetAndMetadata> topicPartitionOffsetAndMetadataMap, Exception kafkaException) {
-          if (kafkaException != null) {
-            LOG.error("Exception while trying to perform an asynchronous commit.", kafkaException);
-            _commitAvailabilityMetrics._failedCommitOffsets.record();
-          } else {
-            _commitAvailabilityMetrics._offsetsCommitted.record();
-            _commitLatencyMetrics.recordCommitComplete();
-          }
+      OffsetCommitCallback commitCallback = (topicPartitionOffsetAndMetadataMap, kafkaException) -> {
+        if (kafkaException != null) {
+          LOG.error("Exception while trying to perform an asynchronous commit.", kafkaException);
+          _commitAvailabilityMetrics._failedCommitOffsets.record();
+        } else {
+          _commitAvailabilityMetrics._offsetsCommitted.record();
+          _commitLatencyMetrics.recordCommitComplete();
         }
       };
 
diff --git a/src/main/java/com/linkedin/xinfra/monitor/services/DefaultMetricsReporterService.java b/src/main/java/com/linkedin/xinfra/monitor/services/DefaultMetricsReporterService.java
index 64a62bf1..88d305f1 100644
--- a/src/main/java/com/linkedin/xinfra/monitor/services/DefaultMetricsReporterService.java
+++ b/src/main/java/com/linkedin/xinfra/monitor/services/DefaultMetricsReporterService.java
@@ -84,6 +84,6 @@ private void reportMetrics() {
         builder.append("\n");
       }
     }
-    LOG.info("{}\n{}", LOG_DIVIDER, builder.toString());
+    LOG.info("{}\n{}", LOG_DIVIDER, builder);
   }
 }
diff --git a/src/main/java/com/linkedin/xinfra/monitor/services/GraphiteMetricsReporterService.java b/src/main/java/com/linkedin/xinfra/monitor/services/GraphiteMetricsReporterService.java
index 24512d7d..6f99ce3a 100644
--- a/src/main/java/com/linkedin/xinfra/monitor/services/GraphiteMetricsReporterService.java
+++ b/src/main/java/com/linkedin/xinfra/monitor/services/GraphiteMetricsReporterService.java
@@ -52,17 +52,14 @@ public GraphiteMetricsReporterService(Map<String, Object> props, String name)
 
   @Override
   public synchronized void start() {
-    _executor.scheduleAtFixedRate(new Runnable() {
-      @Override
-      public void run() {
-        try {
-          GraphiteMetricsReporterService.this.reportMetrics();
-        } catch (Exception e) {
-          LOG.error(_name + "/GraphiteMetricsReporterService failed to report metrics",
-              e);
-        }
+    _executor.scheduleAtFixedRate(() -> {
+      try {
+        GraphiteMetricsReporterService.this.reportMetrics();
+      } catch (Exception e) {
+        LOG.error(_name + "/GraphiteMetricsReporterService failed to report metrics",
+            e);
       }
-      }, _reportIntervalSec, _reportIntervalSec, TimeUnit.SECONDS
+    }, _reportIntervalSec, _reportIntervalSec, TimeUnit.SECONDS
     );
     LOG.info("{}/GraphiteMetricsReporterService started", _name);
   }
diff --git a/src/main/java/com/linkedin/xinfra/monitor/services/OffsetCommitService.java b/src/main/java/com/linkedin/xinfra/monitor/services/OffsetCommitService.java
index 18c31803..22d1dc34 100644
--- a/src/main/java/com/linkedin/xinfra/monitor/services/OffsetCommitService.java
+++ b/src/main/java/com/linkedin/xinfra/monitor/services/OffsetCommitService.java
@@ -134,12 +134,7 @@ public class OffsetCommitService implements Service {
     _consumerNetworkClient = new ConsumerNetworkClient(logContext, kafkaClient, metadata, _time, retryBackoffMs,
         config.getInt(ConsumerConfig.REQUEST_TIMEOUT_MS_CONFIG), heartbeatIntervalMs);
 
-    ThreadFactory threadFactory = new ThreadFactory() {
-      @Override
-      public Thread newThread(Runnable runnable) {
-        return new Thread(runnable, serviceName + SERVICE_SUFFIX);
-      }
-    };
+    ThreadFactory threadFactory = runnable -> new Thread(runnable, serviceName + SERVICE_SUFFIX);
     _scheduledExecutorService = Executors.newSingleThreadScheduledExecutor(threadFactory);
 
     LOGGER.info("OffsetCommitService's ConsumerConfig - {}", Utils.prettyPrint(config.values()));
diff --git a/src/main/java/com/linkedin/xinfra/monitor/services/OffsetCommitServiceFactory.java b/src/main/java/com/linkedin/xinfra/monitor/services/OffsetCommitServiceFactory.java
index 87bd4f88..dc0352db 100644
--- a/src/main/java/com/linkedin/xinfra/monitor/services/OffsetCommitServiceFactory.java
+++ b/src/main/java/com/linkedin/xinfra/monitor/services/OffsetCommitServiceFactory.java
@@ -74,9 +74,7 @@ private Properties prepareConfigs(Map<String, Object> props) {
 
     Map<String, String> customProps = (Map<String, String>) props.get(CommonServiceConfig.CONSUMER_PROPS_CONFIG);
     if (customProps != null) {
-      for (Map.Entry<String, String> entry : customProps.entrySet()) {
-        consumerProps.put(entry.getKey(), entry.getValue());
-      }
+      consumerProps.putAll(customProps);
     }
 
     return consumerProps;
diff --git a/src/main/java/com/linkedin/xinfra/monitor/services/SignalFxMetricsReporterService.java b/src/main/java/com/linkedin/xinfra/monitor/services/SignalFxMetricsReporterService.java
index e84f1200..bf95a08a 100644
--- a/src/main/java/com/linkedin/xinfra/monitor/services/SignalFxMetricsReporterService.java
+++ b/src/main/java/com/linkedin/xinfra/monitor/services/SignalFxMetricsReporterService.java
@@ -52,8 +52,8 @@ public SignalFxMetricsReporterService(Map<String, Object> props, String name) th
 
     _executor = Executors.newSingleThreadScheduledExecutor();
     _metricRegistry = new MetricRegistry();
-    _metricMap = new HashMap<String, SettableDoubleGauge>();
-    _dimensionsMap = new HashMap<String, String>();
+    _metricMap = new HashMap<>();
+    _dimensionsMap = new HashMap<>();
     if (props.containsKey(SignalFxMetricsReporterServiceConfig.SIGNALFX_METRIC_DIMENSION)) {
       _dimensionsMap = (Map<String, String>) props.get(SignalFxMetricsReporterServiceConfig.SIGNALFX_METRIC_DIMENSION);
     }
diff --git a/src/main/java/com/linkedin/xinfra/monitor/services/metrics/OffsetCommitServiceMetrics.java b/src/main/java/com/linkedin/xinfra/monitor/services/metrics/OffsetCommitServiceMetrics.java
index b6a6e753..16127b48 100644
--- a/src/main/java/com/linkedin/xinfra/monitor/services/metrics/OffsetCommitServiceMetrics.java
+++ b/src/main/java/com/linkedin/xinfra/monitor/services/metrics/OffsetCommitServiceMetrics.java
@@ -13,7 +13,6 @@
 import java.util.Map;
 import org.apache.kafka.common.MetricName;
 import org.apache.kafka.common.metrics.Measurable;
-import org.apache.kafka.common.metrics.MetricConfig;
 import org.apache.kafka.common.metrics.Metrics;
 import org.apache.kafka.common.metrics.Sensor;
 import org.apache.kafka.common.metrics.stats.Avg;
@@ -59,27 +58,24 @@ public OffsetCommitServiceMetrics(final Metrics metrics, final Map<String, Strin
             "The total count of group coordinator unsuccessfully receiving consumer offset commit requests.", tags),
         new CumulativeSum());
 
-    Measurable measurable = new Measurable() {
-      @Override
-      public double measure(MetricConfig config, long now) {
-        double offsetCommitSuccessRate = (double) metrics.metrics()
-            .get(metrics.metricName(SUCCESS_RATE_METRIC, METRIC_GROUP_NAME, tags))
-            .metricValue();
-        double offsetCommitFailureRate = (double) metrics.metrics()
-            .get(metrics.metricName(FAILURE_RATE_METRIC, METRIC_GROUP_NAME, tags))
-            .metricValue();
-
-        if (new Double(offsetCommitSuccessRate).isNaN()) {
-          offsetCommitSuccessRate = 0;
-        }
-
-        if (new Double(offsetCommitFailureRate).isNaN()) {
-          offsetCommitFailureRate = 0;
-        }
-
-        return offsetCommitSuccessRate + offsetCommitFailureRate > 0 ? offsetCommitSuccessRate / (
-            offsetCommitSuccessRate + offsetCommitFailureRate) : 0;
+    Measurable measurable = (config, now) -> {
+      double offsetCommitSuccessRate = (double) metrics.metrics()
+          .get(metrics.metricName(SUCCESS_RATE_METRIC, METRIC_GROUP_NAME, tags))
+          .metricValue();
+      double offsetCommitFailureRate = (double) metrics.metrics()
+          .get(metrics.metricName(FAILURE_RATE_METRIC, METRIC_GROUP_NAME, tags))
+          .metricValue();
+
+      if (new Double(offsetCommitSuccessRate).isNaN()) {
+        offsetCommitSuccessRate = 0;
+      }
+
+      if (new Double(offsetCommitFailureRate).isNaN()) {
+        offsetCommitFailureRate = 0;
       }
+
+      return offsetCommitSuccessRate + offsetCommitFailureRate > 0 ? offsetCommitSuccessRate / (
+          offsetCommitSuccessRate + offsetCommitFailureRate) : 0;
     };
 
     metrics.addMetric(new MetricName("offset-commit-availability-avg", METRIC_GROUP_NAME,
diff --git a/src/test/java/com/linkedin/xinfra/monitor/XinfraMonitorTest.java b/src/test/java/com/linkedin/xinfra/monitor/XinfraMonitorTest.java
index 9867718d..ab7b2586 100644
--- a/src/test/java/com/linkedin/xinfra/monitor/XinfraMonitorTest.java
+++ b/src/test/java/com/linkedin/xinfra/monitor/XinfraMonitorTest.java
@@ -10,14 +10,19 @@
 
 package com.linkedin.xinfra.monitor;
 
+import com.linkedin.xinfra.monitor.common.Utils;
 import com.linkedin.xinfra.monitor.services.ServiceFactory;
 import com.linkedin.xinfra.monitor.services.Service;
+
+import java.time.Duration;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicReference;
+
+import org.testng.Assert;
 import org.testng.annotations.Test;
 
 
@@ -71,16 +76,16 @@ public void run() {
 
     t.start();
     xinfraMonitor.start();
-    Thread.sleep(100);
+    Utils.delay(Duration.ofMillis(100));
     xinfraMonitor.stop();
     t.join(500);
-    org.testng.Assert.assertFalse(t.isAlive());
-    org.testng.Assert.assertEquals(error.get(), null);
+    Assert.assertFalse(t.isAlive());
+    Assert.assertNull(error.get());
   }
 
   private XinfraMonitor xinfraMonitor() throws Exception {
     FakeService.clearCounters();
-    Map<String, Map> config = new HashMap<>();
+    Map<String, Map<String, Object>> config = new HashMap<>();
     Map<String, Object> fakeServiceConfig = new HashMap<>();
 
     fakeServiceConfig.put(XinfraMonitorConstants.CLASS_NAME_CONFIG, FakeService.class.getName());
@@ -106,7 +111,7 @@ public FakeServiceFactory(Map config, String serviceInstanceName) {
 
     @SuppressWarnings("unchecked")
     @Override
-    public Service createService() throws Exception {
+    public Service createService() {
 
       return new XinfraMonitorTest.FakeService(_config, _serviceInstanceName);
 
@@ -120,7 +125,7 @@ static final class FakeService implements Service {
     private final AtomicBoolean _isRunning = new AtomicBoolean();
 
     /** required */
-    public FakeService(Map<String, Map> config, String serviceInstanceName) {
+    public FakeService(Map<String, Map<String, Object>> config, String serviceInstanceName) {
 
     }
 
diff --git a/src/test/java/com/linkedin/xinfra/monitor/services/ConsumeServiceTest.java b/src/test/java/com/linkedin/xinfra/monitor/services/ConsumeServiceTest.java
index 8d11fd04..370028f5 100644
--- a/src/test/java/com/linkedin/xinfra/monitor/services/ConsumeServiceTest.java
+++ b/src/test/java/com/linkedin/xinfra/monitor/services/ConsumeServiceTest.java
@@ -14,6 +14,8 @@
 import com.linkedin.xinfra.monitor.consumer.BaseConsumerRecord;
 import com.linkedin.xinfra.monitor.consumer.KMBaseConsumer;
 import com.linkedin.xinfra.monitor.services.metrics.CommitLatencyMetrics;
+
+import java.time.Duration;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.concurrent.CompletableFuture;
@@ -25,7 +27,6 @@
 import org.apache.kafka.common.TopicPartition;
 import org.apache.kafka.common.metrics.Metrics;
 import org.mockito.Mockito;
-import org.mockito.invocation.InvocationOnMock;
 import org.mockito.stubbing.Answer;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -83,12 +84,9 @@ public void commitAvailabilityTest() throws Exception {
     consumeService.startConsumeThreadForTesting();
     Assert.assertTrue(consumeService.isRunning());
 
-    /* in milliseconds */
-    long threadStartDelay = TimeUnit.SECONDS.toMillis(THREAD_START_DELAY_SECONDS);
-
-    /* Thread.sleep safe to do here instead of ScheduledExecutorService
+    /* delay safe to do here instead of ScheduledExecutorService
     *  We want to sleep current thread so that consumeService can start running for enough seconds. */
-    Thread.sleep(threadStartDelay);
+    Utils.delay(Duration.ofSeconds(THREAD_START_DELAY_SECONDS));
     Assert.assertNotNull(metrics.metrics().get(metrics.metricName("offsets-committed-total", METRIC_GROUP_NAME, tags)).metricValue());
     Assert.assertNotNull(metrics.metrics().get(metrics.metricName("failed-commit-offsets-total", METRIC_GROUP_NAME,
         tags)).metricValue());
@@ -112,12 +110,9 @@ public void commitLatencyTest() throws Exception {
     consumeService.startConsumeThreadForTesting();
     Assert.assertTrue(consumeService.isRunning());
 
-    /* in milliseconds */
-    long threadStartDelay = TimeUnit.SECONDS.toMillis(THREAD_START_DELAY_SECONDS);
-
-    /* Thread.sleep safe to do here instead of ScheduledExecutorService
+    /* delay safe to do here instead of ScheduledExecutorService
      *  We want to sleep current thread so that consumeService can start running for enough seconds. */
-    Thread.sleep(threadStartDelay);
+    Utils.delay(Duration.ofSeconds(THREAD_START_DELAY_SECONDS));
 
     shutdownConsumeService(consumeService);
   }
@@ -148,16 +143,13 @@ private ConsumeService consumeService() throws Exception {
     /* define return value */
     Mockito.when(kmBaseConsumer.lastCommitted()).thenReturn(MOCK_LAST_COMMITTED_OFFSET);
     Mockito.when(kmBaseConsumer.committed(Mockito.any())).thenReturn(new OffsetAndMetadata(FIRST_OFFSET));
-    Mockito.doAnswer(new Answer<Void>() {
-      @Override
-      public Void answer(InvocationOnMock invocationOnMock) {
-        OffsetCommitCallback callback = invocationOnMock.getArgument(0);
-        Map<TopicPartition, OffsetAndMetadata> committedOffsets = new HashMap<>();
-        committedOffsets.put(new TopicPartition(TOPIC, PARTITION), new OffsetAndMetadata(FIRST_OFFSET));
-        callback.onComplete(committedOffsets, null);
+    Mockito.doAnswer((Answer<Void>) invocationOnMock -> {
+      OffsetCommitCallback callback = invocationOnMock.getArgument(0);
+      Map<TopicPartition, OffsetAndMetadata> committedOffsets = new HashMap<>();
+      committedOffsets.put(new TopicPartition(TOPIC, PARTITION), new OffsetAndMetadata(FIRST_OFFSET));
+      callback.onComplete(committedOffsets, null);
 
-        return null;
-      }
+      return null;
     }).when(kmBaseConsumer).commitAsync(Mockito.any(OffsetCommitCallback.class));
 
 
@@ -190,13 +182,13 @@ public void run() {
 
     thread.start();
     consumeService.startConsumeThreadForTesting();
-    Thread.sleep(100);
+    Utils.delay(Duration.ofMillis(100));
 
     consumeService.stop();
     thread.join(500);
 
     Assert.assertFalse(thread.isAlive());
-    Assert.assertEquals(error.get(), null);
+    Assert.assertNull(error.get());
 
   }
 
@@ -207,8 +199,7 @@ public void run() {
    */
   private Metrics consumeServiceMetrics(ConsumeService consumeService) {
     setup();
-    Metrics metrics = consumeService.metrics();
-    return metrics;
+    return consumeService.metrics();
   }
 
   /**