Enable ModifierOrderCheck Checkstyle rule (#2673)

* Enable ModifierOrderCheck Checkstyle rule

* Fix violations for `static` and `abstract` modifier
* Remove redundant code in the `TcpNioConnection`
* Mark `connectionFactoryName` as `@Nullable` in the `TcpConnectionSupport`
ctor and its inheritors
* Fix some smells according IDEA suggestions in the affected classes
* This should fix some Sonar smells as well

* * Fix `HeaderMapperTests`

* * Polishing `TcpConnection` code style and fix Javdocs

spring-integration-core/src/main/java/org/springframework/integration/codec/kryo/AbstractKryoRegistrar.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2015-2016 the original author or authors.
+ * Copyright 2015-2018 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.
@@ -28,11 +28,13 @@ import com.esotericsoftware.kryo.Registration;
  * Base class for {@link KryoRegistrar} implementations.
  *
  * @author David Turanski
+ * @author Artem Bilan
+ *
  * @since 4.2
  */
 public abstract class AbstractKryoRegistrar implements KryoRegistrar {
 
-	protected final static Kryo kryo = new Kryo();
+	protected static final Kryo kryo = new Kryo();
 
 	protected final Log log = LogFactory.getLog(this.getClass());
 
@@ -55,7 +57,7 @@ public abstract class AbstractKryoRegistrar implements KryoRegistrar {
 		Registration existing = kryo.getRegistration(id);
 
 		if (existing != null) {
-			throw new RuntimeException((String.format("registration already exists %s", existing)));
+			throw new RuntimeException("registration already exists " + existing);
 		}
 
 		if (this.log.isInfoEnabled()) {

spring-integration-core/src/main/java/org/springframework/integration/codec/kryo/RegistrationIds.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2015-2016 the original author or authors.
+ * Copyright 2015-2018 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.
@@ -20,12 +20,14 @@ package org.springframework.integration.codec.kryo;
  * Default registration ids for serializers provided by the framework.
  *
  * @author Gary Russell
+ * @author Artem Bilan
+ *
  * @since 4.2
  *
  */
 public final class RegistrationIds {
 
-	public final static int DEFAULT_FILE_REGISTRATION_ID = 40;
+	public static final int DEFAULT_FILE_REGISTRATION_ID = 40;
 
 	public static final int DEFAULT_MESSAGEHEADERS_ID = 41;
 

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

@@ -89,7 +89,7 @@ class DefaultConfiguringBeanFactoryPostProcessor
 
 	private static final Log logger = LogFactory.getLog(DefaultConfiguringBeanFactoryPostProcessor.class);
 
-	private final static IntegrationConverterInitializer INTEGRATION_CONVERTER_INITIALIZER =
+	private static final IntegrationConverterInitializer INTEGRATION_CONVERTER_INITIALIZER =
 			new IntegrationConverterInitializer();
 
 	private static final Set<Integer> registriesProcessed = new HashSet<>();
@@ -152,17 +152,22 @@ class DefaultConfiguringBeanFactoryPostProcessor
 	 */
 	private void registerNullChannel() {
 		if (this.beanFactory.containsBean(IntegrationContextUtils.NULL_CHANNEL_BEAN_NAME)) {
-			BeanDefinition nullChannelDefinition;
+			BeanDefinition nullChannelDefinition = null;
 			if (this.beanFactory.containsBeanDefinition(IntegrationContextUtils.NULL_CHANNEL_BEAN_NAME)) {
 				nullChannelDefinition =
 						this.beanFactory.getBeanDefinition(IntegrationContextUtils.NULL_CHANNEL_BEAN_NAME);
 			}
 			else {
-				nullChannelDefinition =
-						((BeanDefinitionRegistry) this.beanFactory.getParentBeanFactory())
-								.getBeanDefinition(IntegrationContextUtils.NULL_CHANNEL_BEAN_NAME); // NOSONAR not null
+				BeanDefinitionRegistry parentBeanFactory =
+						(BeanDefinitionRegistry) this.beanFactory.getParentBeanFactory();
+				if (parentBeanFactory != null) {
+					nullChannelDefinition =
+							parentBeanFactory.getBeanDefinition(IntegrationContextUtils.NULL_CHANNEL_BEAN_NAME);
+				}
 			}
-			if (!NullChannel.class.getName().equals(nullChannelDefinition.getBeanClassName())) {
+
+			if (nullChannelDefinition != null &&
+					!NullChannel.class.getName().equals(nullChannelDefinition.getBeanClassName())) {
 				throw new IllegalStateException("The bean name '" + IntegrationContextUtils.NULL_CHANNEL_BEAN_NAME
 						+ "' is reserved.");
 			}

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2010 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -27,26 +27,27 @@ import org.springframework.util.Assert;
  * FactoryBean for creating Expression instances.
  *
  * @author Mark Fisher
+ * @author Artem Bilan
+ *
  * @since 2.0
  */
 public class ExpressionFactoryBean extends AbstractFactoryBean<Expression> {
 
-	private final static ExpressionParser DEFAULT_PARSER = new SpelExpressionParser();
-
+	private static final ExpressionParser DEFAULT_PARSER = new SpelExpressionParser();
 
 	private final String expressionString;
 
-	private volatile ExpressionParser parser = DEFAULT_PARSER;
+	private ExpressionParser parser = DEFAULT_PARSER;
 
 
 	public ExpressionFactoryBean(String expressionString) {
-		Assert.hasText(expressionString, "expressionString must not be empty or null");
+		Assert.hasText(expressionString, "'expressionString' must not be empty or null");
 		this.expressionString = expressionString;
 	}
 
 
 	public void setParserConfiguration(SpelParserConfiguration parserConfiguration) {
-		Assert.notNull(parserConfiguration, "parserConfiguration must not be null");
+		Assert.notNull(parserConfiguration, "'parserConfiguration' must not be null");
 		this.parser = new SpelExpressionParser(parserConfiguration);
 	}
 
@@ -57,7 +58,7 @@ public class ExpressionFactoryBean extends AbstractFactoryBean<Expression> {
 	}
 
 	@Override
-	protected Expression createInstance() throws Exception {
+	protected Expression createInstance() {
 		return this.parser.parseExpression(this.expressionString);
 	}
 

spring-integration-core/src/main/java/org/springframework/integration/config/xml/ConverterParser.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -32,23 +32,27 @@ import org.springframework.util.StringUtils;
  * @author Oleg Zhurakousky
  * @author Mark Fisher
  * @author Artem Bilan
+ *
  * @since 2.0
  */
 public class ConverterParser extends AbstractBeanDefinitionParser {
 
-	private final static IntegrationConverterInitializer INTEGRATION_CONVERTER_INITIALIZER = new IntegrationConverterInitializer();
+	private static final IntegrationConverterInitializer INTEGRATION_CONVERTER_INITIALIZER =
+			new IntegrationConverterInitializer();
 
 	@Override
 	protected AbstractBeanDefinition parseInternal(Element element, ParserContext parserContext) {
 		BeanDefinitionRegistry registry = parserContext.getRegistry();
-		BeanComponentDefinition converterDefinition = IntegrationNamespaceUtils.parseInnerHandlerDefinition(element, parserContext);
+		BeanComponentDefinition converterDefinition =
+				IntegrationNamespaceUtils.parseInnerHandlerDefinition(element, parserContext);
 		if (converterDefinition != null) {
 			INTEGRATION_CONVERTER_INITIALIZER.registerConverter(registry, converterDefinition);
 		}
 		else {
 			String beanName = element.getAttribute("ref");
 			Assert.isTrue(StringUtils.hasText(beanName),
-					"Either a 'ref' attribute pointing to a Converter or a <bean> sub-element defining a Converter is required.");
+					"Either a 'ref' attribute pointing to a Converter " +
+							"or a <bean> sub-element defining a Converter is required.");
 			INTEGRATION_CONVERTER_INITIALIZER.registerConverter(registry, new RuntimeBeanReference(beanName));
 		}
 		return null;

spring-integration-core/src/main/java/org/springframework/integration/dsl/IntegrationComponentSpec.java

@@ -37,7 +37,7 @@ import org.springframework.expression.spel.standard.SpelExpressionParser;
 public abstract class IntegrationComponentSpec<S extends IntegrationComponentSpec<S, T>, T>
 		implements FactoryBean<T>, InitializingBean, DisposableBean {
 
-	protected final static SpelExpressionParser PARSER = new SpelExpressionParser();
+	protected static final SpelExpressionParser PARSER = new SpelExpressionParser();
 
 	protected final Log logger = LogFactory.getLog(getClass()); // NOSONAR
 

spring-integration-core/src/main/java/org/springframework/integration/dsl/Transformers.java

@@ -42,8 +42,8 @@ import org.springframework.integration.transformer.PayloadSerializingTransformer
 import org.springframework.integration.transformer.PayloadTypeConvertingTransformer;
 import org.springframework.integration.transformer.StreamTransformer;
 import org.springframework.integration.transformer.SyslogToMapTransformer;
+import org.springframework.lang.Nullable;
 import org.springframework.messaging.Message;
-import org.springframework.util.Assert;
 
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
@@ -58,14 +58,16 @@ import reactor.core.publisher.Mono;
  */
 public abstract class Transformers {
 
-	private final static SpelExpressionParser PARSER = new SpelExpressionParser();
+	private static final SpelExpressionParser PARSER = new SpelExpressionParser();
 
 	public static ObjectToStringTransformer objectToString() {
 		return objectToString(null);
 	}
 
-	public static ObjectToStringTransformer objectToString(String charset) {
-		return charset != null ? new ObjectToStringTransformer(charset) : new ObjectToStringTransformer();
+	public static ObjectToStringTransformer objectToString(@Nullable String charset) {
+		return charset != null
+				? new ObjectToStringTransformer(charset)
+				: new ObjectToStringTransformer();
 	}
 
 	public static ObjectToMapTransformer toMap() {
@@ -100,20 +102,21 @@ public abstract class Transformers {
 		return toJson(null, null, null);
 	}
 
-	public static ObjectToJsonTransformer toJson(JsonObjectMapper<?, ?> jsonObjectMapper) {
+	public static ObjectToJsonTransformer toJson(@Nullable JsonObjectMapper<?, ?> jsonObjectMapper) {
 		return toJson(jsonObjectMapper, null, null);
 	}
 
-	public static ObjectToJsonTransformer toJson(JsonObjectMapper<?, ?> jsonObjectMapper,
-			ObjectToJsonTransformer.ResultType resultType) {
+	public static ObjectToJsonTransformer toJson(@Nullable JsonObjectMapper<?, ?> jsonObjectMapper,
+			@Nullable ObjectToJsonTransformer.ResultType resultType) {
 		return toJson(jsonObjectMapper, resultType, null);
 	}
 
-	public static ObjectToJsonTransformer toJson(String contentType) {
+	public static ObjectToJsonTransformer toJson(@Nullable String contentType) {
 		return toJson(null, null, contentType);
 	}
 
-	public static ObjectToJsonTransformer toJson(JsonObjectMapper<?, ?> jsonObjectMapper, String contentType) {
+	public static ObjectToJsonTransformer toJson(@Nullable JsonObjectMapper<?, ?> jsonObjectMapper,
+			@Nullable String contentType) {
 		return toJson(jsonObjectMapper, null, contentType);
 	}
 
@@ -124,16 +127,18 @@ public abstract class Transformers {
 	 * @return the ObjectToJsonTransformer
 	 * @since 5.0.9
 	 */
-	public static ObjectToJsonTransformer toJson(ObjectToJsonTransformer.ResultType resultType) {
+	public static ObjectToJsonTransformer toJson(@Nullable ObjectToJsonTransformer.ResultType resultType) {
 		return toJson(null, resultType, null);
 	}
 
-	public static ObjectToJsonTransformer toJson(ObjectToJsonTransformer.ResultType resultType, String contentType) {
+	public static ObjectToJsonTransformer toJson(@Nullable ObjectToJsonTransformer.ResultType resultType,
+			@Nullable String contentType) {
 		return toJson(null, resultType, contentType);
 	}
 
-	public static ObjectToJsonTransformer toJson(JsonObjectMapper<?, ?> jsonObjectMapper,
-			ObjectToJsonTransformer.ResultType resultType, String contentType) {
+	public static ObjectToJsonTransformer toJson(@Nullable JsonObjectMapper<?, ?> jsonObjectMapper,
+			@Nullable ObjectToJsonTransformer.ResultType resultType, @Nullable String contentType) {
+
 		ObjectToJsonTransformer transformer;
 		if (jsonObjectMapper != null) {
 			if (resultType != null) {
@@ -159,15 +164,17 @@ public abstract class Transformers {
 		return fromJson(null, null);
 	}
 
-	public static JsonToObjectTransformer fromJson(Class<?> targetClass) {
+	public static JsonToObjectTransformer fromJson(@Nullable Class<?> targetClass) {
 		return fromJson(targetClass, null);
 	}
 
-	public static JsonToObjectTransformer fromJson(JsonObjectMapper<?, ?> jsonObjectMapper) {
+	public static JsonToObjectTransformer fromJson(@Nullable JsonObjectMapper<?, ?> jsonObjectMapper) {
 		return fromJson(null, jsonObjectMapper);
 	}
 
-	public static JsonToObjectTransformer fromJson(Class<?> targetClass, JsonObjectMapper<?, ?> jsonObjectMapper) {
+	public static JsonToObjectTransformer fromJson(@Nullable Class<?> targetClass,
+			@Nullable JsonObjectMapper<?, ?> jsonObjectMapper) {
+
 		return new JsonToObjectTransformer(targetClass, jsonObjectMapper);
 	}
 
@@ -175,7 +182,7 @@ public abstract class Transformers {
 		return serializer(null);
 	}
 
-	public static PayloadSerializingTransformer serializer(Serializer<Object> serializer) {
+	public static PayloadSerializingTransformer serializer(@Nullable Serializer<Object> serializer) {
 		PayloadSerializingTransformer transformer = new PayloadSerializingTransformer();
 		if (serializer != null) {
 			transformer.setSerializer(serializer);
@@ -187,7 +194,7 @@ public abstract class Transformers {
 		return deserializer(null, whiteListPatterns);
 	}
 
-	public static PayloadDeserializingTransformer deserializer(Deserializer<Object> deserializer,
+	public static PayloadDeserializingTransformer deserializer(@Nullable Deserializer<Object> deserializer,
 			String... whiteListPatterns) {
 		PayloadDeserializingTransformer transformer = new PayloadDeserializingTransformer();
 		transformer.setWhiteListPatterns(whiteListPatterns);
@@ -198,7 +205,6 @@ public abstract class Transformers {
 	}
 
 	public static <T, U> PayloadTypeConvertingTransformer<T, U> converter(Converter<T, U> converter) {
-		Assert.notNull(converter, "The Converter<?, ?> is required for the PayloadTypeConvertingTransformer");
 		PayloadTypeConvertingTransformer<T, U> transformer = new PayloadTypeConvertingTransformer<>();
 		transformer.setConverter(converter);
 		return transformer;
@@ -276,7 +282,7 @@ public abstract class Transformers {
 	 * @param charset the charset.
 	 * @return the {@link StreamTransformer} instance.
 	 */
-	public static StreamTransformer fromStream(String charset) {
+	public static StreamTransformer fromStream(@Nullable String charset) {
 		return new StreamTransformer(charset);
 	}
 

spring-integration-core/src/main/java/org/springframework/integration/gateway/GatewayMethodInboundMessageMapper.java

@@ -84,10 +84,12 @@ import org.springframework.util.StringUtils;
  */
 class GatewayMethodInboundMessageMapper implements InboundMessageMapper<Object[]>, BeanFactoryAware {
 
-	private final static Log logger = LogFactory.getLog(GatewayMethodInboundMessageMapper.class);
+	private static final Log logger = LogFactory.getLog(GatewayMethodInboundMessageMapper.class);
 
 	private static final SpelExpressionParser PARSER = new SpelExpressionParser();
 
+	private final Map<String, Expression> parameterPayloadExpressions = new HashMap<>();
+
 	private final Method method;
 
 	private final Map<String, Expression> headerExpressions;
@@ -102,13 +104,11 @@ class GatewayMethodInboundMessageMapper implements InboundMessageMapper<Object[]
 
 	private final MessageBuilderFactory messageBuilderFactory;
 
-	private volatile Expression payloadExpression;
+	private Expression payloadExpression;
 
-	private final Map<String, Expression> parameterPayloadExpressions = new HashMap<String, Expression>();
+	private EvaluationContext payloadExpressionEvaluationContext;
 
-	private volatile StandardEvaluationContext payloadExpressionEvaluationContext;
-
-	private volatile BeanFactory beanFactory;
+	private BeanFactory beanFactory;
 
 	private Expression sendTimeoutExpression;
 
@@ -127,6 +127,7 @@ class GatewayMethodInboundMessageMapper implements InboundMessageMapper<Object[]
 			@Nullable Map<String, Expression> globalHeaderExpressions,
 			@Nullable MethodArgsMessageMapper mapper,
 			@Nullable MessageBuilderFactory messageBuilderFactory) {
+
 		this(method, headerExpressions, globalHeaderExpressions, null, mapper, messageBuilderFactory);
 	}
 
@@ -189,7 +190,7 @@ class GatewayMethodInboundMessageMapper implements InboundMessageMapper<Object[]
 	}
 
 	@Nullable
-	private Message<?> mapArgumentsToMessage(Object[] arguments, Map<String, Object> headers) {
+	private Message<?> mapArgumentsToMessage(Object[] arguments, @Nullable Map<String, Object> headers) {
 		try {
 			return this.argsMapper.toMessage(new MethodArgsHolder(this.method, arguments), headers);
 		}
@@ -205,6 +206,7 @@ class GatewayMethodInboundMessageMapper implements InboundMessageMapper<Object[]
 
 	private Map<String, Object> evaluateHeaders(EvaluationContext methodInvocationEvaluationContext,
 			Map<String, Expression> headerExpressions) {
+
 		Map<String, Object> evaluatedHeaders = new HashMap<>();
 		for (Map.Entry<String, Expression> entry : headerExpressions.entrySet()) {
 			Object value = entry.getValue().getValue(methodInvocationEvaluationContext);
@@ -277,7 +279,7 @@ class GatewayMethodInboundMessageMapper implements InboundMessageMapper<Object[]
 			String expressionString = (String) AnnotationUtils.getValue(payload);
 			Assert.hasText(expressionString,
 					"@Payload at method-level on a Gateway must provide a non-empty Expression.");
-			expression = PARSER.parseExpression(expressionString);
+			expression = PARSER.parseExpression(expressionString); // NOSONAR protected with hasText()
 		}
 		return expression;
 	}
@@ -285,7 +287,7 @@ class GatewayMethodInboundMessageMapper implements InboundMessageMapper<Object[]
 	public class DefaultMethodArgsMessageMapper implements MethodArgsMessageMapper {
 
 		@Override
-		public Message<?> toMessage(MethodArgsHolder holder, @Nullable Map<String, Object> headers) throws Exception {
+		public Message<?> toMessage(MethodArgsHolder holder, @Nullable Map<String, Object> headers) {
 			Object messageOrPayload = null;
 			boolean foundPayloadAnnotation = false;
 			Object[] arguments = holder.getArgs();
@@ -296,13 +298,15 @@ class GatewayMethodInboundMessageMapper implements InboundMessageMapper<Object[]
 							: new HashMap<>();
 			if (GatewayMethodInboundMessageMapper.this.payloadExpression != null) {
 				messageOrPayload =
-						GatewayMethodInboundMessageMapper.this.payloadExpression.getValue(methodInvocationEvaluationContext);
+						GatewayMethodInboundMessageMapper.this.payloadExpression.getValue(
+								methodInvocationEvaluationContext);
 			}
 			for (int i = 0; i < GatewayMethodInboundMessageMapper.this.parameterList.size(); i++) {
 				Object argumentValue = arguments[i];
 				MethodParameter methodParameter = GatewayMethodInboundMessageMapper.this.parameterList.get(i);
 				Annotation annotation =
-						MessagingAnnotationUtils.findMessagePartAnnotation(methodParameter.getParameterAnnotations(), false);
+						MessagingAnnotationUtils.findMessagePartAnnotation(methodParameter.getParameterAnnotations(),
+								false);
 				if (annotation != null) {
 					if (annotation.annotationType().equals(Payload.class)) {
 						if (messageOrPayload != null) {
@@ -329,7 +333,8 @@ class GatewayMethodInboundMessageMapper implements InboundMessageMapper<Object[]
 					else if (annotation.annotationType().equals(Headers.class)) {
 						if (argumentValue != null) {
 							if (!(argumentValue instanceof Map)) {
-								throw new IllegalArgumentException("@Headers annotation is only valid for Map-typed parameters");
+								throw new IllegalArgumentException(
+										"@Headers annotation is only valid for Map-typed parameters");
 							}
 							for (Object key : ((Map<?, ?>) argumentValue).keySet()) {
 								Assert.isInstanceOf(String.class, key, "Invalid header name [" + key +
@@ -369,10 +374,11 @@ class GatewayMethodInboundMessageMapper implements InboundMessageMapper<Object[]
 						v -> GatewayMethodInboundMessageMapper.this.replyTimeoutExpression
 								.getValue(methodInvocationEvaluationContext, Long.class));
 			}
+			MessageBuilderFactory messageBuilderFactory = GatewayMethodInboundMessageMapper.this.messageBuilderFactory;
 			AbstractIntegrationMessageBuilder<?> builder =
 					(messageOrPayload instanceof Message)
-							? GatewayMethodInboundMessageMapper.this.messageBuilderFactory.fromMessage((Message<?>) messageOrPayload)
-							: GatewayMethodInboundMessageMapper.this.messageBuilderFactory.withPayload(messageOrPayload);
+							? messageBuilderFactory.fromMessage((Message<?>) messageOrPayload)
+							: messageBuilderFactory.withPayload(messageOrPayload);
 			builder.copyHeadersIfAbsent(headers);
 			// Explicit headers in XML override any @Header annotations...
 			if (!CollectionUtils.isEmpty(GatewayMethodInboundMessageMapper.this.headerExpressions)) {

spring-integration-core/src/main/java/org/springframework/integration/handler/AbstractMessageProcessor.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -22,10 +22,12 @@ import org.springframework.messaging.Message;
 /**
  * @author Mark Fisher
  * @author Dave Syer
+ * @author Artem Bilan
+ *
  * @since 2.0
  */
 public abstract class AbstractMessageProcessor<T> extends AbstractExpressionEvaluator implements MessageProcessor<T> {
 
-	abstract public T processMessage(Message<?> message);
+	public abstract T processMessage(Message<?> message);
 
 }

spring-integration-core/src/main/java/org/springframework/integration/support/MapBuilder.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016 the original author or authors.
+ * Copyright 2016-2018 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.
@@ -29,13 +29,14 @@ import org.springframework.expression.spel.standard.SpelExpressionParser;
  * @param <V> The Map value type.
  *
  * @author Artem Bilan
+ *
  * @since 5.0
  */
 public class MapBuilder<B extends MapBuilder<B, K, V>, K, V> {
 
-	protected final static SpelExpressionParser PARSER = new SpelExpressionParser();
+	protected static final SpelExpressionParser PARSER = new SpelExpressionParser();
 
-	private final Map<K, V> map = new HashMap<K, V>();
+	private final Map<K, V> map = new HashMap<>();
 
 	public B put(K key, V value) {
 		this.map.put(key, value);

spring-integration-core/src/main/java/org/springframework/integration/support/channel/BeanFactoryChannelResolver.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -45,11 +45,11 @@ import org.springframework.util.Assert;
  */
 public class BeanFactoryChannelResolver implements DestinationResolver<MessageChannel>, BeanFactoryAware {
 
-	private final static Log logger = LogFactory.getLog(BeanFactoryChannelResolver.class);
+	private static final Log logger = LogFactory.getLog(BeanFactoryChannelResolver.class);
 
-	private volatile BeanFactory beanFactory;
+	private BeanFactory beanFactory;
 
-	private volatile HeaderChannelRegistry replyChannelRegistry;
+	private HeaderChannelRegistry replyChannelRegistry;
 
 	private volatile boolean initialized;
 

spring-integration-core/src/main/java/org/springframework/integration/support/management/micrometer/MicrometerMetricsCaptor.java

@@ -40,6 +40,7 @@ import io.micrometer.core.instrument.Timer;
  * The Micrometer implementation of {@link MetricsCaptor}.
  *
  * @author Gary Russell
+ * @author Artem Bilan
  *
  * @since 5.0.4
  *
@@ -148,7 +149,7 @@ public class MicrometerMetricsCaptor implements MetricsCaptor {
 
 	}
 
-	protected static abstract class AbstractMeter<M extends Meter> implements MeterFacade {
+	protected abstract static class AbstractMeter<M extends Meter> implements MeterFacade {
 
 		protected final MeterRegistry meterRegistry; // NOSONAR
 

spring-integration-core/src/test/java/org/springframework/integration/config/annotation/SubscriberOrderTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -141,7 +141,7 @@ public class SubscriberOrderTests {
 	}
 
 
-	static abstract class AbstractTestBean {
+	abstract static class AbstractTestBean {
 
 		@Order(4)
 		abstract void fourth(Message<?> message);
@@ -157,7 +157,7 @@ public class SubscriberOrderTests {
 
 		private final int maxCallsPerMethod;
 
-		private volatile List<Integer> calls = new ArrayList<Integer>();
+		private final List<Integer> calls = new ArrayList<>();
 
 
 		TestBean(int maxCallsPerMethod) {
@@ -166,7 +166,7 @@ public class SubscriberOrderTests {
 
 
 		void reset() {
-			this.calls = new ArrayList<Integer>();
+			this.calls.clear();
 		}
 
 		@Order(3)
@@ -211,6 +211,7 @@ public class SubscriberOrderTests {
 			}
 			this.calls.add(methodNumber);
 		}
+
 	}
 
 }

spring-integration-core/src/test/java/org/springframework/integration/core/TimeBasedUUIDGenerator.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -24,18 +24,22 @@ import java.util.logging.Logger;
 
 /**
  * @author Oleg Zhurakousky
+ * @author Artem Bilan
  *
  */
 class TimeBasedUUIDGenerator {
 
+	static final Object lock = new Object();
+
 	private static final Logger logger = Logger.getLogger(TimeBasedUUIDGenerator.class.getName());
 
-	public static final Object lock = new Object();
+	private static final long macAddress = getMac();
 
 	private static boolean canNotDetermineMac = true;
+
 	private static long lastTime;
+
 	private static long clockSequence = 0;
-	private static final long macAddress = getMac();
 
 	private TimeBasedUUIDGenerator() {
 		super();
@@ -45,11 +49,11 @@ class TimeBasedUUIDGenerator {
 	 * Will generate unique time based UUID where the next UUID is
 	 * always greater then the previous.
 	 */
-	public final static UUID generateId() {
+	static UUID generateId() {
 		return generateIdFromTimestamp(System.currentTimeMillis());
 	}
 
-	public final static UUID generateIdFromTimestamp(long currentTimeMillis) {
+	static UUID generateIdFromTimestamp(long currentTimeMillis) {
 		long time;
 
 		synchronized (lock) {
@@ -78,11 +82,12 @@ class TimeBasedUUIDGenerator {
 
 		clock_seq_hi_and_reserved <<= 48;
 
-		long cls = 0 | clock_seq_hi_and_reserved;
+		long cls = clock_seq_hi_and_reserved;
 
 		long lsb = cls | macAddress;
 		if (canNotDetermineMac) {
-			logger.warning("UUID generation process was not able to determine your MAC address. Returning random UUID (non version 1 UUID)");
+			logger.warning("UUID generation process was not able to determine your MAC address. " +
+					"Returning random UUID (non version 1 UUID)");
 			return UUID.randomUUID();
 		}
 		else {
@@ -98,11 +103,9 @@ class TimeBasedUUIDGenerator {
 				//byte[] mac = ni.getHardwareAddress(); // availabe since Java 1.6
 				byte[] mac = "01:23:45:67:89:ab".getBytes();
 				//Converts array of unsigned bytes to an long
-				if (mac != null) {
-					for (int i = 0; i < mac.length; i++) {
-						macAddressAsLong <<= 8;
-						macAddressAsLong ^= (long) mac[i] & 0xFF;
-					}
+				for (byte aMac : mac) {
+					macAddressAsLong <<= 8;
+					macAddressAsLong ^= (long) aMac & 0xFF;
 				}
 			}
 			canNotDetermineMac = false;
@@ -112,4 +115,5 @@ class TimeBasedUUIDGenerator {
 		}
 		return macAddressAsLong;
 	}
+
 }

spring-integration-core/src/test/java/org/springframework/integration/mapping/HeaderMapperTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -34,11 +34,14 @@ import org.springframework.integration.mapping.AbstractHeaderMapper.HeaderMatche
 import org.springframework.integration.mapping.AbstractHeaderMapper.PatternBasedHeaderMatcher;
 import org.springframework.integration.mapping.AbstractHeaderMapper.PrefixBasedMatcher;
 import org.springframework.integration.mapping.AbstractHeaderMapper.SinglePatternBasedHeaderMatcher;
+import org.springframework.lang.Nullable;
 import org.springframework.messaging.MessageHeaders;
 import org.springframework.util.StringUtils;
 
 /**
  * @author Stephane Nicoll
+ * @author Artem Bilan
+ *
  * @since 4.1
  */
 public class HeaderMapperTests {
@@ -75,8 +78,8 @@ public class HeaderMapperTests {
 		GenericTestProperties properties = createSimpleGenericTestProperties();
 
 		Map<String, Object> attributes = this.mapper.toHeadersFromRequest(properties);
-		assertEquals(null, attributes.get(GenericTestHeaders.APP_ID));
-		assertEquals(null, attributes.get(GenericTestHeaders.REQUEST_ONLY));
+		assertNull(attributes.get(GenericTestHeaders.APP_ID));
+		assertNull(attributes.get(GenericTestHeaders.REQUEST_ONLY));
 		assertEquals("reply-123", attributes.get(GenericTestHeaders.REPLY_ONLY));
 		assertEquals("bar", attributes.get("foo"));
 		assertEquals("Wrong number of mapped header(s)", 2, attributes.size());
@@ -310,7 +313,7 @@ public class HeaderMapperTests {
 	}
 
 	public MessageHeaders createSimpleMessageHeaders() {
-		Map<String, Object> headers = new HashMap<String, Object>();
+		Map<String, Object> headers = new HashMap<>();
 		headers.put(GenericTestHeaders.APP_ID, "myAppId");
 		headers.put(GenericTestHeaders.REDELIVERED, true);
 		headers.put(GenericTestHeaders.REQUEST_ONLY, "request-456");
@@ -324,7 +327,6 @@ public class HeaderMapperTests {
 
 	@Test
 	public void prefixHeaderPatternMatching() {
-		@SuppressWarnings("deprecation")
 		PatternBasedHeaderMatcher strategy =
 				new PatternBasedHeaderMatcher(Collections.singleton("fOo*"));
 
@@ -338,7 +340,6 @@ public class HeaderMapperTests {
 
 	@Test
 	public void suffixHeaderPatternMatching() {
-		@SuppressWarnings("deprecation")
 		PatternBasedHeaderMatcher strategy =
 				new PatternBasedHeaderMatcher(Collections.singleton("*fOo"));
 
@@ -435,7 +436,7 @@ public class HeaderMapperTests {
 	}
 
 
-	private static abstract class GenericTestHeaders {
+	private abstract static class GenericTestHeaders {
 
 		public static final String PREFIX = "generic_";
 
@@ -464,7 +465,7 @@ public class HeaderMapperTests {
 
 		@Override
 		protected Map<String, Object> extractStandardHeaders(GenericTestProperties source) {
-			Map<String, Object> result = new HashMap<String, Object>();
+			Map<String, Object> result = new HashMap<>();
 			if (StringUtils.hasText(source.getAppId())) {
 				result.put(GenericTestHeaders.APP_ID, source.getAppId());
 			}
@@ -547,6 +548,7 @@ public class HeaderMapperTests {
 			this.appId = appId;
 		}
 
+		@Nullable
 		public Integer getTransactionSize() {
 			return transactionSize;
 		}
@@ -555,6 +557,7 @@ public class HeaderMapperTests {
 			this.transactionSize = transactionSize;
 		}
 
+		@Nullable
 		public Boolean getRedelivered() {
 			return redelivered;
 		}

spring-integration-core/src/test/java/org/springframework/integration/message/TestHandlers.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -25,6 +25,7 @@ import org.springframework.messaging.Message;
  * Factory for handler beans that are useful for testing.
  *
  * @author Mark Fisher
+ * @author Artem Bilan
  */
 @SuppressWarnings("unused")
 public abstract class TestHandlers {
@@ -32,8 +33,9 @@ public abstract class TestHandlers {
 	/**
 	 * Create a handler that always returns null.
 	 */
-	public final static Object nullHandler() {
+	public static final Object nullHandler() {
 		return new Object() {
+
 			public Message<?> handle(Message<?> message) {
 				return null;
 			}
@@ -43,8 +45,9 @@ public abstract class TestHandlers {
 	/**
 	 * Create a handler that simply returns the {@link Message} it receives.
 	 */
-	public final static Object echoHandler() {
+	public static final Object echoHandler() {
 		return new Object() {
+
 			public Message<?> handle(Message<?> message) {
 				return message;
 			}
@@ -54,8 +57,9 @@ public abstract class TestHandlers {
 	/**
 	 * Create a handler that increments the provided counter.
 	 */
-	public final static Object countingHandler(final AtomicInteger counter) {
+	public static final Object countingHandler(final AtomicInteger counter) {
 		return new Object() {
+
 			public Message<?> handle(Message<?> message) {
 				counter.incrementAndGet();
 				return null;
@@ -66,8 +70,9 @@ public abstract class TestHandlers {
 	/**
 	 * Create a handler that counts down on the provided latch.
 	 */
-	public final static Object countDownHandler(final CountDownLatch latch) {
+	public static final Object countDownHandler(final CountDownLatch latch) {
 		return new Object() {
+
 			public Message<?> handle(Message<?> message) {
 				latch.countDown();
 				return null;
@@ -79,8 +84,9 @@ public abstract class TestHandlers {
 	 * Create a handler that counts down on the provided latch
 	 * and also increments the provided counter.
 	 */
-	public final static Object countingCountDownHandler(final AtomicInteger counter, final CountDownLatch latch) {
+	public static final Object countingCountDownHandler(final AtomicInteger counter, final CountDownLatch latch) {
 		return new Object() {
+
 			public Message<?> handle(Message<?> message) {
 				counter.incrementAndGet();
 				latch.countDown();

spring-integration-core/src/test/java/org/springframework/integration/support/management/DefaultMessageChannelMetricsTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2017 the original author or authors.
+ * Copyright 2017-2018 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.
@@ -25,12 +25,13 @@ import org.springframework.messaging.Message;
 
 /**
  * @author Ivan Krizsan
+ * @author Artem Bilan
  */
 public class DefaultMessageChannelMetricsTests {
 
-	protected final static int MESSAGE_COUNT = 10;
+	protected static final int MESSAGE_COUNT = 10;
 
-	protected final static long SEND_TIMEOUT = 1;
+	protected static final long SEND_TIMEOUT = 1;
 
 	@Test
 	public void errorCountWithCountsEnabledOnlySuccessTest() {

spring-integration-core/src/test/java/org/springframework/integration/support/management/ExponentialMovingAverageRateTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -18,7 +18,6 @@ package org.springframework.integration.support.management;
 
 import static org.hamcrest.Matchers.lessThan;
 import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotEquals;
 import static org.junit.Assert.assertThat;
 import static org.junit.Assert.assertTrue;
@@ -37,11 +36,12 @@ import org.springframework.util.StopWatch;
  * @author Dave Syer
  * @author Gary Russell
  * @author Steven Swor
+ * @author Artem Bilan
  */
 @Ignore("Very sensitive to the time. Don't forget to test after some changes.")
 public class ExponentialMovingAverageRateTests {
 
-	private final static Log logger = LogFactory.getLog(ExponentialMovingAverageRateTests.class);
+	private static final Log logger = LogFactory.getLog(ExponentialMovingAverageRateTests.class);
 
 	private final ExponentialMovingAverageRate history = new ExponentialMovingAverageRate(1., 10., 10, true);
 
@@ -54,7 +54,7 @@ public class ExponentialMovingAverageRateTests {
 
 	@Test
 	@SuppressWarnings("unchecked")
-	public void testGetTimeSinceLastMeasurement() throws Exception {
+	public void testGetTimeSinceLastMeasurement() {
 		long sleepTime = 20L;
 
 		// fill history with the same value.
@@ -67,7 +67,7 @@ public class ExponentialMovingAverageRateTests {
 		assertEquals(Long.valueOf(now), times.peekLast());
 
 		//increment just so we'll have a different value between first and last
-		history.increment(System.nanoTime()  - sleepTime * 1000000);
+		history.increment(System.nanoTime() - sleepTime * 1000000);
 		assertNotEquals(times.peekFirst(), times.peekLast());
 
 		/*
@@ -76,7 +76,7 @@ public class ExponentialMovingAverageRateTests {
 		 * the queue, then we should be closer to the sleep time than we are to
 		 * 2 x sleepTime, but we should definitely be greater than the sleep
 		 * time.
-		*/
+		 */
 		double timeSinceLastMeasurement = history.getTimeSinceLastMeasurement();
 		assertTrue(timeSinceLastMeasurement > sleepTime);
 		assertTrue(timeSinceLastMeasurement <= (1.5 * sleepTime));
@@ -126,7 +126,6 @@ public class ExponentialMovingAverageRateTests {
 	}
 
 	@Test
-	@Ignore
 	public void testGetStandardDeviation() throws Exception {
 		assertEquals(0, history.getStandardDeviation(), 0.01);
 		Thread.sleep(20L);
@@ -138,13 +137,12 @@ public class ExponentialMovingAverageRateTests {
 	}
 
 	@Test
-	@Ignore
 	public void testReset() throws Exception {
 		assertEquals(0, history.getStandardDeviation(), 0.01);
 		history.increment();
 		Thread.sleep(30L);
 		history.increment();
-		assertFalse(0 == history.getStandardDeviation());
+		assertNotEquals(0, history.getStandardDeviation(), 0.0);
 		history.reset();
 		assertEquals(0, history.getStandardDeviation(), 0.01);
 		assertEquals(0, history.getCount());
@@ -155,7 +153,6 @@ public class ExponentialMovingAverageRateTests {
 	}
 
 	@Test
-	@Ignore // tolerance needed is too dependent on hardware
 	public void testRate() {
 		ExponentialMovingAverageRate rate = new ExponentialMovingAverageRate(1, 60, 10);
 		int count = 1000000;
@@ -170,7 +167,6 @@ public class ExponentialMovingAverageRateTests {
 	}
 
 	@Test
-	@Ignore
 	public void testPerf() {
 		ExponentialMovingAverageRate rate = new ExponentialMovingAverageRate(1, 60, 10);
 		for (int i = 0; i < 1000000; i++) {