diff --git a/streampipes-messaging-nats/pom.xml b/streampipes-messaging-nats/pom.xml
index 5fdc5a690f..af42b43c2d 100644
--- a/streampipes-messaging-nats/pom.xml
+++ b/streampipes-messaging-nats/pom.xml
@@ -46,4 +46,26 @@
         </dependency>
     </dependencies>
 
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-checkstyle-plugin</artifactId>
+                <executions>
+                    <execution>
+                        <id>validate</id>
+                        <phase>validate</phase>
+                        <goals>
+                            <goal>check</goal>
+                        </goals>
+                    </execution>
+                </executions>
+                <configuration>
+                    <logViolationsToConsole>true</logViolationsToConsole>
+                    <failOnViolation>true</failOnViolation>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+    
 </project>
diff --git a/streampipes-messaging-nats/src/main/java/org/apache/streampipes/messaging/nats/AbstractNatsConnector.java b/streampipes-messaging-nats/src/main/java/org/apache/streampipes/messaging/nats/AbstractNatsConnector.java
index f72f1e961d..5253cdf243 100644
--- a/streampipes-messaging-nats/src/main/java/org/apache/streampipes/messaging/nats/AbstractNatsConnector.java
+++ b/streampipes-messaging-nats/src/main/java/org/apache/streampipes/messaging/nats/AbstractNatsConnector.java
@@ -1,27 +1,29 @@
 /*
- *   Licensed to the Apache Software Foundation (ASF) under one or more
- *   contributor license agreements.  See the NOTICE file distributed with
- *   this work for additional information regarding copyright ownership.
- *   The ASF licenses this file to You under the Apache License, Version 2.0
- *   (the "License"); you may not use this file except in compliance with
- *   the License.  You may obtain a copy of the License at
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
  *
- *      http://www.apache.org/licenses/LICENSE-2.0
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
- *   Unless required by applicable law or agreed to in writing, software
- *   distributed under the License is distributed on an "AS IS" BASIS,
- *   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- *   See the License for the specific language governing permissions and
- *   limitations under the License.
  */
 
 package org.apache.streampipes.messaging.nats;
 
+import org.apache.streampipes.model.grounding.NatsTransportProtocol;
+import org.apache.streampipes.model.nats.NatsConfig;
+
 import io.nats.client.Connection;
 import io.nats.client.Nats;
 import io.nats.client.Options;
-import org.apache.streampipes.model.grounding.NatsTransportProtocol;
-import org.apache.streampipes.model.nats.NatsConfig;
 
 import java.io.IOException;
 import java.time.Duration;
diff --git a/streampipes-messaging-nats/src/main/java/org/apache/streampipes/messaging/nats/NatsConsumer.java b/streampipes-messaging-nats/src/main/java/org/apache/streampipes/messaging/nats/NatsConsumer.java
index b54fe0f672..ee02fab772 100644
--- a/streampipes-messaging-nats/src/main/java/org/apache/streampipes/messaging/nats/NatsConsumer.java
+++ b/streampipes-messaging-nats/src/main/java/org/apache/streampipes/messaging/nats/NatsConsumer.java
@@ -1,31 +1,33 @@
 /*
- *   Licensed to the Apache Software Foundation (ASF) under one or more
- *   contributor license agreements.  See the NOTICE file distributed with
- *   this work for additional information regarding copyright ownership.
- *   The ASF licenses this file to You under the Apache License, Version 2.0
- *   (the "License"); you may not use this file except in compliance with
- *   the License.  You may obtain a copy of the License at
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
  *
- *      http://www.apache.org/licenses/LICENSE-2.0
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
- *   Unless required by applicable law or agreed to in writing, software
- *   distributed under the License is distributed on an "AS IS" BASIS,
- *   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- *   See the License for the specific language governing permissions and
- *   limitations under the License.
  */
 
 package org.apache.streampipes.messaging.nats;
 
-import io.nats.client.Connection;
-import io.nats.client.Dispatcher;
-import io.nats.client.Subscription;
 import org.apache.streampipes.commons.exceptions.SpRuntimeException;
 import org.apache.streampipes.messaging.EventConsumer;
 import org.apache.streampipes.messaging.InternalEventProcessor;
 import org.apache.streampipes.model.grounding.NatsTransportProtocol;
 import org.apache.streampipes.model.nats.NatsConfig;
 
+import io.nats.client.Connection;
+import io.nats.client.Dispatcher;
+import io.nats.client.Subscription;
+
 import java.io.IOException;
 import java.util.concurrent.TimeoutException;
 
@@ -69,8 +71,7 @@ public boolean isConnected() {
   private void createSubscription(InternalEventProcessor<byte[]> eventProcessor) {
     dispatcher = natsConnection.createDispatcher((message) -> {});
 
-    this.subscription = dispatcher.subscribe(subject, (message) -> {
-      eventProcessor.onEvent(message.getData());
-    });
+    this.subscription = dispatcher.subscribe(subject, (message) ->
+        eventProcessor.onEvent(message.getData()));
   }
 }
diff --git a/streampipes-messaging-nats/src/main/java/org/apache/streampipes/messaging/nats/NatsPublisher.java b/streampipes-messaging-nats/src/main/java/org/apache/streampipes/messaging/nats/NatsPublisher.java
index f4b0c75f6d..06e7cc7325 100644
--- a/streampipes-messaging-nats/src/main/java/org/apache/streampipes/messaging/nats/NatsPublisher.java
+++ b/streampipes-messaging-nats/src/main/java/org/apache/streampipes/messaging/nats/NatsPublisher.java
@@ -1,27 +1,29 @@
 /*
- *   Licensed to the Apache Software Foundation (ASF) under one or more
- *   contributor license agreements.  See the NOTICE file distributed with
- *   this work for additional information regarding copyright ownership.
- *   The ASF licenses this file to You under the Apache License, Version 2.0
- *   (the "License"); you may not use this file except in compliance with
- *   the License.  You may obtain a copy of the License at
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
  *
- *      http://www.apache.org/licenses/LICENSE-2.0
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
- *   Unless required by applicable law or agreed to in writing, software
- *   distributed under the License is distributed on an "AS IS" BASIS,
- *   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- *   See the License for the specific language governing permissions and
- *   limitations under the License.
  */
 
 package org.apache.streampipes.messaging.nats;
 
-import io.nats.client.Connection;
 import org.apache.streampipes.commons.exceptions.SpRuntimeException;
 import org.apache.streampipes.messaging.EventProducer;
 import org.apache.streampipes.model.grounding.NatsTransportProtocol;
 
+import io.nats.client.Connection;
+
 import java.io.IOException;
 import java.util.concurrent.TimeoutException;
 
diff --git a/streampipes-messaging-nats/src/main/java/org/apache/streampipes/messaging/nats/NatsUtils.java b/streampipes-messaging-nats/src/main/java/org/apache/streampipes/messaging/nats/NatsUtils.java
index fb15db9351..7b49469621 100644
--- a/streampipes-messaging-nats/src/main/java/org/apache/streampipes/messaging/nats/NatsUtils.java
+++ b/streampipes-messaging-nats/src/main/java/org/apache/streampipes/messaging/nats/NatsUtils.java
@@ -1,24 +1,25 @@
 /*
- *   Licensed to the Apache Software Foundation (ASF) under one or more
- *   contributor license agreements.  See the NOTICE file distributed with
- *   this work for additional information regarding copyright ownership.
- *   The ASF licenses this file to You under the Apache License, Version 2.0
- *   (the "License"); you may not use this file except in compliance with
- *   the License.  You may obtain a copy of the License at
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
  *
- *      http://www.apache.org/licenses/LICENSE-2.0
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
- *   Unless required by applicable law or agreed to in writing, software
- *   distributed under the License is distributed on an "AS IS" BASIS,
- *   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- *   See the License for the specific language governing permissions and
- *   limitations under the License.
  */
-
 package org.apache.streampipes.messaging.nats;
 
-import io.nats.client.Options;
 import org.apache.streampipes.model.nats.NatsConfig;
+
+import io.nats.client.Options;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
diff --git a/streampipes-messaging-nats/src/main/java/org/apache/streampipes/messaging/nats/SpNatsProtocol.java b/streampipes-messaging-nats/src/main/java/org/apache/streampipes/messaging/nats/SpNatsProtocol.java
index 847507ca04..bf3abb3de2 100644
--- a/streampipes-messaging-nats/src/main/java/org/apache/streampipes/messaging/nats/SpNatsProtocol.java
+++ b/streampipes-messaging-nats/src/main/java/org/apache/streampipes/messaging/nats/SpNatsProtocol.java
@@ -1,18 +1,19 @@
 /*
- *   Licensed to the Apache Software Foundation (ASF) under one or more
- *   contributor license agreements.  See the NOTICE file distributed with
- *   this work for additional information regarding copyright ownership.
- *   The ASF licenses this file to You under the Apache License, Version 2.0
- *   (the "License"); you may not use this file except in compliance with
- *   the License.  You may obtain a copy of the License at
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
  *
- *      http://www.apache.org/licenses/LICENSE-2.0
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
- *   Unless required by applicable law or agreed to in writing, software
- *   distributed under the License is distributed on an "AS IS" BASIS,
- *   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- *   See the License for the specific language governing permissions and
- *   limitations under the License.
  */
 
 package org.apache.streampipes.messaging.nats;
@@ -24,13 +25,14 @@
 
 public class SpNatsProtocol implements SpProtocolDefinition<NatsTransportProtocol> {
 
-  private EventConsumer<NatsTransportProtocol> natsConsumer;
-  private EventProducer<NatsTransportProtocol> natsProducer;
+  private final EventConsumer<NatsTransportProtocol> natsConsumer;
+  private final EventProducer<NatsTransportProtocol> natsProducer;
 
   public SpNatsProtocol() {
     this.natsConsumer = new NatsConsumer();
     this.natsProducer = new NatsPublisher();
   }
+
   @Override
   public EventConsumer<NatsTransportProtocol> getConsumer() {
     return this.natsConsumer;
diff --git a/streampipes-messaging-nats/src/main/java/org/apache/streampipes/messaging/nats/SpNatsProtocolFactory.java b/streampipes-messaging-nats/src/main/java/org/apache/streampipes/messaging/nats/SpNatsProtocolFactory.java
index 7d6812cfde..5d18e2b0b7 100644
--- a/streampipes-messaging-nats/src/main/java/org/apache/streampipes/messaging/nats/SpNatsProtocolFactory.java
+++ b/streampipes-messaging-nats/src/main/java/org/apache/streampipes/messaging/nats/SpNatsProtocolFactory.java
@@ -1,18 +1,19 @@
 /*
- *   Licensed to the Apache Software Foundation (ASF) under one or more
- *   contributor license agreements.  See the NOTICE file distributed with
- *   this work for additional information regarding copyright ownership.
- *   The ASF licenses this file to You under the Apache License, Version 2.0
- *   (the "License"); you may not use this file except in compliance with
- *   the License.  You may obtain a copy of the License at
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
  *
- *      http://www.apache.org/licenses/LICENSE-2.0
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
- *   Unless required by applicable law or agreed to in writing, software
- *   distributed under the License is distributed on an "AS IS" BASIS,
- *   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- *   See the License for the specific language governing permissions and
- *   limitations under the License.
  */
 package org.apache.streampipes.messaging.nats;