Fix Checkstyle violations

* Add `validateOnlyOverlapping = false` for `RequireThis` Checkstyle rule
* Add `this.` to caught places
* Use `CustomizableThreadFactory` instead of raw interface in the
`UnicastSendingMessageHandler`

spring-integration-core/src/main/java/org/springframework/integration/aop/PublisherAnnotationBeanPostProcessor.java

@@ -106,9 +106,6 @@ public class PublisherAnnotationBeanPostProcessor extends ProxyConfig
 	@Override
 	public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
 		Class<?> targetClass = AopUtils.getTargetClass(bean);
-		if (targetClass == null) {
-			return bean;
-		}
 
 		// the set will hold records of prior class scans and will contain the bean classes that can not
 		// be assigned to the Advisor interface and therefore can be short circuited
@@ -131,7 +128,7 @@ public class PublisherAnnotationBeanPostProcessor extends ProxyConfig
 		}
 		else {
 			// cannot apply advisor
-			nonApplicableCache.add(targetClass);
+			this.nonApplicableCache.add(targetClass);
 			return bean;
 		}
 	}

spring-integration-core/src/main/java/org/springframework/integration/config/annotation/MessagingAnnotationPostProcessor.java

@@ -163,7 +163,7 @@ public class MessagingAnnotationPostProcessor implements BeanPostProcessor, Bean
 		ReflectionUtils.doWithMethods(beanClass, method -> {
 			Map<Class<? extends Annotation>, List<Annotation>> annotationChains = new HashMap<>();
 			for (Class<? extends Annotation> annotationType :
-					MessagingAnnotationPostProcessor.this.postProcessors.keySet()) {
+					this.postProcessors.keySet()) {
 				if (AnnotatedElementUtils.isAnnotated(method, annotationType.getName())) {
 					List<Annotation> annotationChain = getAnnotationChain(method, annotationType);
 					if (annotationChain.size() > 0) {
@@ -179,7 +179,7 @@ public class MessagingAnnotationPostProcessor implements BeanPostProcessor, Bean
 			}
 
 			if (annotationChains.size() == 0) {
-				noAnnotationsCache.add(beanClass);
+				this.noAnnotationsCache.add(beanClass);
 			}
 		}, ReflectionUtils.USER_DECLARED_METHODS);
 

spring-integration-core/src/main/java/org/springframework/integration/dispatcher/RoundRobinLoadBalancingStrategy.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -31,6 +31,8 @@ import org.springframework.messaging.MessageHandler;
  * @author Iwein Fuld
  * @author Mark Fisher
  * @author Oleg Zhurakousky
+ * @author Artem Bilan
+ *
  * @since 1.0.3
  */
 public class RoundRobinLoadBalancingStrategy implements LoadBalancingStrategy {
@@ -43,7 +45,7 @@ public class RoundRobinLoadBalancingStrategy implements LoadBalancingStrategy {
 	 * iteration, so it guarantees all handlers are returned once on subsequent
 	 * <code>next()</code> invocations.
 	 */
-	public final Iterator<MessageHandler> getHandlerIterator(final Message<?> message, final Collection<MessageHandler> handlers) {
+	public final Iterator<MessageHandler> getHandlerIterator(Message<?> message, Collection<MessageHandler> handlers) {
 		int size = handlers.size();
 		if (size < 2) {
 			this.getNextHandlerStartIndex(size);
@@ -54,28 +56,29 @@ public class RoundRobinLoadBalancingStrategy implements LoadBalancingStrategy {
 	}
 
 	private Iterator<MessageHandler> buildHandlerIterator(int size, final MessageHandler[] handlers) {
-
 		int nextHandlerStartIndex = getNextHandlerStartIndex(size);
 
-		final MessageHandler[] reorderedHandlers = new MessageHandler[size];
+		MessageHandler[] reorderedHandlers = new MessageHandler[size];
 
 		System.arraycopy(handlers, nextHandlerStartIndex, reorderedHandlers, 0, size - nextHandlerStartIndex);
-		System.arraycopy(handlers, 0, reorderedHandlers, size - nextHandlerStartIndex, 0 + nextHandlerStartIndex);
+		System.arraycopy(handlers, 0, reorderedHandlers, size - nextHandlerStartIndex, nextHandlerStartIndex);
 
 		return new Iterator<MessageHandler>() {
+
 			int currentIndex = 0;
 
 			public boolean hasNext() {
-				return currentIndex < reorderedHandlers.length;
+				return this.currentIndex < reorderedHandlers.length;
 			}
 
 			public MessageHandler next() {
-				return reorderedHandlers[currentIndex++];
+				return reorderedHandlers[this.currentIndex++];
 			}
 
 			public void remove() {
 				throw new UnsupportedOperationException("Remove is not supported by this Iterator");
 			}
+
 		};
 	}
 
@@ -93,4 +96,5 @@ public class RoundRobinLoadBalancingStrategy implements LoadBalancingStrategy {
 			return size;
 		}
 	}
+
 }