Polishing previous commit

Resolves #1382
Resolves #1491

spring-cloud-stream-integration-tests/src/test/java/org/springframework/cloud/stream/config/StreamListenerAnnotatedMethodArgumentsTests.java

@@ -21,6 +21,8 @@ import java.util.List;
 import java.util.Map;
 import java.util.UUID;
 
+import javax.validation.Valid;
+
 import org.junit.Test;
 
 import org.springframework.boot.SpringApplication;
@@ -39,8 +41,6 @@ import org.springframework.messaging.handler.annotation.Payload;
 import org.springframework.messaging.handler.annotation.support.MethodArgumentNotValidException;
 import org.springframework.util.MimeType;
 
-import javax.validation.Valid;
-
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.junit.Assert.fail;
 import static org.springframework.cloud.stream.binding.StreamListenerErrorMessages.INVALID_DECLARATIVE_METHOD_PARAMETERS;
@@ -119,7 +119,7 @@ public class StreamListenerAnnotatedMethodArgumentsTests {
 		context.close();
 	}
 
-	@EnableBinding(Processor.class)
+	@EnableBinding(Sink.class)
 	@EnableAutoConfiguration
 	public static class TestPojoWithAnnotatedArguments {
 
@@ -135,7 +135,7 @@ public class StreamListenerAnnotatedMethodArgumentsTests {
 		}
 	}
 
-	@EnableBinding(Processor.class)
+	@EnableBinding(Sink.class)
 	@EnableAutoConfiguration
 	public static class TestPojoWithInvalidInputAnnotatedArgument {
 

spring-cloud-stream-integration-tests/src/test/java/org/springframework/cloud/stream/config/StreamListenerHandlerMethodTests.java

@@ -46,8 +46,6 @@ import org.springframework.messaging.handler.annotation.Payload;
 import org.springframework.messaging.handler.annotation.SendTo;
 import org.springframework.util.Assert;
 
-import javax.validation.Valid;
-
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.junit.Assert.fail;
 import static org.springframework.cloud.stream.binding.StreamListenerErrorMessages.AMBIGUOUS_MESSAGE_HANDLER_METHOD_ARGUMENTS;

spring-cloud-stream-integration-tests/src/test/java/org/springframework/cloud/stream/config/StreamListenerTestUtils.java

@@ -16,12 +16,14 @@
 
 package org.springframework.cloud.stream.config;
 
+import javax.validation.constraints.NotBlank;
+
 import org.springframework.cloud.stream.annotation.Input;
 import org.springframework.cloud.stream.annotation.Output;
 import org.springframework.messaging.MessageChannel;
 import org.springframework.messaging.SubscribableChannel;
 
-import javax.validation.constraints.NotBlank;
+
 
 /**
  * @author Ilayaperumal Gopinathan

spring-cloud-stream/src/main/java/org/springframework/cloud/stream/config/BinderFactoryConfiguration.java

@@ -53,6 +53,7 @@ import org.springframework.core.io.UrlResource;
 import org.springframework.core.io.support.PropertiesLoaderUtils;
 import org.springframework.integration.context.IntegrationContextUtils;
 import org.springframework.integration.handler.support.HandlerMethodArgumentResolversHolder;
+import org.springframework.lang.Nullable;
 import org.springframework.messaging.handler.annotation.support.DefaultMessageHandlerMethodFactory;
 import org.springframework.messaging.handler.annotation.support.MessageHandlerMethodFactory;
 import org.springframework.util.ClassUtils;
@@ -133,7 +134,7 @@ public class BinderFactoryConfiguration {
 
 	@Bean
 	public MessageConverterConfigurer messageConverterConfigurer(BindingServiceProperties bindingServiceProperties,
-																CompositeMessageConverterFactory compositeMessageConverterFactory) {
+								CompositeMessageConverterFactory compositeMessageConverterFactory) {
 		return new MessageConverterConfigurer(bindingServiceProperties, compositeMessageConverterFactory);
 	}
 
@@ -145,7 +146,7 @@ public class BinderFactoryConfiguration {
 
 	@Bean
 	public MessageSourceBindingTargetFactory messageSourceFactory(CompositeMessageConverterFactory compositeMessageConverterFactory,
-																CompositeMessageChannelConfigurer compositeMessageChannelConfigurer) {
+								CompositeMessageChannelConfigurer compositeMessageChannelConfigurer) {
 		return new MessageSourceBindingTargetFactory(compositeMessageConverterFactory.getMessageConverterForAllRegistered(), compositeMessageChannelConfigurer);
 	}
 
@@ -159,8 +160,8 @@ public class BinderFactoryConfiguration {
 
 	@Bean
 	public static MessageHandlerMethodFactory messageHandlerMethodFactory(CompositeMessageConverterFactory compositeMessageConverterFactory,
-																		@Qualifier(IntegrationContextUtils.ARGUMENT_RESOLVERS_BEAN_NAME) HandlerMethodArgumentResolversHolder ahmar,
-																		Validator validator) {
+								@Qualifier(IntegrationContextUtils.ARGUMENT_RESOLVERS_BEAN_NAME) HandlerMethodArgumentResolversHolder ahmar,
+								@Nullable Validator validator) {
 		DefaultMessageHandlerMethodFactory messageHandlerMethodFactory = new DefaultMessageHandlerMethodFactory();
 		messageHandlerMethodFactory.setMessageConverter(compositeMessageConverterFactory.getMessageConverterForAllRegistered());
 		messageHandlerMethodFactory.setCustomArgumentResolvers(ahmar.getResolvers());