diff --git a/pulsar-broker/src/main/java/org/apache/pulsar/broker/PulsarService.java b/pulsar-broker/src/main/java/org/apache/pulsar/broker/PulsarService.java
index be85f545e62ba..991b8940292dd 100644
--- a/pulsar-broker/src/main/java/org/apache/pulsar/broker/PulsarService.java
+++ b/pulsar-broker/src/main/java/org/apache/pulsar/broker/PulsarService.java
@@ -653,12 +653,9 @@ config, localMetadataStore, getZkClient(), bkClientFactory, ioEventLoopGroup
             attributeMap.put(WebService.ATTRIBUTE_PULSAR_NAME, this);
             Map<String, Object> vipAttributeMap = Maps.newHashMap();
             vipAttributeMap.put(VipStatus.ATTRIBUTE_STATUS_FILE_PATH, this.config.getStatusFilePath());
-            vipAttributeMap.put(VipStatus.ATTRIBUTE_IS_READY_PROBE, new Supplier<Boolean>() {
-                @Override
-                public Boolean get() {
-                    // Ensure the VIP status is only visible when the broker is fully initialized
-                    return state == State.Started;
-                }
+            vipAttributeMap.put(VipStatus.ATTRIBUTE_IS_READY_PROBE, (Supplier<Boolean>) () -> {
+                // Ensure the VIP status is only visible when the broker is fully initialized
+                return state == State.Started;
             });
             this.webService.addRestResources("/",
                     VipStatus.class.getPackage().getName(), false, vipAttributeMap);
diff --git a/pulsar-broker/src/main/java/org/apache/pulsar/broker/admin/v2/Bookies.java b/pulsar-broker/src/main/java/org/apache/pulsar/broker/admin/v2/Bookies.java
index 8eae28205b97f..57e5e47435e3a 100644
--- a/pulsar-broker/src/main/java/org/apache/pulsar/broker/admin/v2/Bookies.java
+++ b/pulsar-broker/src/main/java/org/apache/pulsar/broker/admin/v2/Bookies.java
@@ -48,7 +48,6 @@
 import org.apache.pulsar.common.policies.data.RawBookieInfo;
 import org.apache.pulsar.common.util.ObjectMapperFactory;
 import org.apache.pulsar.zookeeper.ZkBookieRackAffinityMapping;
-import org.apache.pulsar.zookeeper.ZooKeeperCache.Deserializer;
 import org.apache.zookeeper.data.Stat;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -67,14 +66,9 @@ public BookiesRackConfiguration getBookiesRackInfo() throws Exception {
         validateSuperUserAccess();
 
         return localZkCache().getData(ZkBookieRackAffinityMapping.BOOKIE_INFO_ROOT_PATH,
-                new Deserializer<BookiesRackConfiguration>() {
-
-                    @Override
-                    public BookiesRackConfiguration deserialize(String key, byte[] content) throws Exception {
-                        return ObjectMapperFactory.getThreadLocal().readValue(content, BookiesRackConfiguration.class);
-                    }
-
-                }).orElse(new BookiesRackConfiguration());
+                (key, content) ->
+                        ObjectMapperFactory.getThreadLocal().readValue(content, BookiesRackConfiguration.class))
+                .orElse(new BookiesRackConfiguration());
     }
 
     @GET
diff --git a/pulsar-broker/src/main/java/org/apache/pulsar/broker/service/BrokerService.java b/pulsar-broker/src/main/java/org/apache/pulsar/broker/service/BrokerService.java
index f14d182c34f6e..2bc1d9cade06e 100644
--- a/pulsar-broker/src/main/java/org/apache/pulsar/broker/service/BrokerService.java
+++ b/pulsar-broker/src/main/java/org/apache/pulsar/broker/service/BrokerService.java
@@ -2125,32 +2125,28 @@ private void updateDynamicServiceConfiguration() {
         }));
         // register a listener: it updates field value and triggers appropriate registered field-listener only if
         // field's value has been changed so, registered doesn't have to update field value in ServiceConfiguration
-        dynamicConfigurationCache.registerListener(new ZooKeeperCacheListener<Map<String, String>>() {
-            @SuppressWarnings("unchecked")
-            @Override
-            public void onUpdate(String path, Map<String, String> data, Stat stat) {
-                if (BROKER_SERVICE_CONFIGURATION_PATH.equalsIgnoreCase(path) && data != null) {
-                    data.forEach((configKey, value) -> {
-                        Field configField = dynamicConfigurationMap.get(configKey).field;
-                        Object newValue = FieldParser.value(data.get(configKey), configField);
-                        if (configField != null) {
-                            Consumer listener = configRegisteredListeners.get(configKey);
-                            try {
-                                Object existingValue = configField.get(pulsar.getConfiguration());
-                                configField.set(pulsar.getConfiguration(), newValue);
-                                log.info("Successfully updated configuration {}/{}", configKey,
-                                        data.get(configKey));
-                                if (listener != null && !existingValue.equals(newValue)) {
-                                    listener.accept(newValue);
-                                }
-                            } catch (Exception e) {
-                                log.error("Failed to update config {}/{}", configKey, newValue);
+        dynamicConfigurationCache.registerListener((path, data, stat) -> {
+            if (BROKER_SERVICE_CONFIGURATION_PATH.equalsIgnoreCase(path) && data != null) {
+                data.forEach((configKey, value) -> {
+                    Field configField = dynamicConfigurationMap.get(configKey).field;
+                    Object newValue = FieldParser.value(data.get(configKey), configField);
+                    if (configField != null) {
+                        Consumer listener = configRegisteredListeners.get(configKey);
+                        try {
+                            Object existingValue = configField.get(pulsar.getConfiguration());
+                            configField.set(pulsar.getConfiguration(), newValue);
+                            log.info("Successfully updated configuration {}/{}", configKey,
+                                    data.get(configKey));
+                            if (listener != null && !existingValue.equals(newValue)) {
+                                listener.accept(newValue);
                             }
-                        } else {
-                            log.error("Found non-dynamic field in dynamicConfigMap {}/{}", configKey, newValue);
+                        } catch (Exception e) {
+                            log.error("Failed to update config {}/{}", configKey, newValue);
                         }
-                    });
-                }
+                    } else {
+                        log.error("Found non-dynamic field in dynamicConfigMap {}/{}", configKey, newValue);
+                    }
+                });
             }
         });
 
diff --git a/pulsar-broker/src/main/java/org/apache/pulsar/broker/service/persistent/PersistentDispatcherMultipleConsumers.java b/pulsar-broker/src/main/java/org/apache/pulsar/broker/service/persistent/PersistentDispatcherMultipleConsumers.java
index 3426355f8de79..90ad1e1e22fe2 100644
--- a/pulsar-broker/src/main/java/org/apache/pulsar/broker/service/persistent/PersistentDispatcherMultipleConsumers.java
+++ b/pulsar-broker/src/main/java/org/apache/pulsar/broker/service/persistent/PersistentDispatcherMultipleConsumers.java
@@ -23,6 +23,7 @@
 import com.google.common.collect.Lists;
 import com.google.common.collect.Range;
 import java.util.Collections;
+import java.util.Comparator;
 import java.util.List;
 import java.util.Optional;
 import java.util.Set;
@@ -151,7 +152,7 @@ public synchronized void addConsumer(Consumer consumer) throws BrokerServiceExce
         }
 
         consumerList.add(consumer);
-        consumerList.sort((c1, c2) -> c1.getPriorityLevel() - c2.getPriorityLevel());
+        consumerList.sort(Comparator.comparingInt(Consumer::getPriorityLevel));
         consumerSet.add(consumer);
     }