Apply "instanceof pattern matching" in spring-messaging

This commit also applies additional clean-up tasks such as the following.

- final fields
- diamond operator (<>) for anonymous inner classes
- for-each loop

This has only been applied to `src/main/java`.

spring-messaging/src/main/java/org/springframework/messaging/converter/AbstractMessageConverter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -314,8 +314,7 @@ public abstract class AbstractMessageConverter implements SmartMessageConverter
 
 
 	static Type getResolvedType(Class<?> targetClass, @Nullable Object conversionHint) {
-		if (conversionHint instanceof MethodParameter) {
+		if (conversionHint instanceof MethodParameter param) {
-			MethodParameter param = (MethodParameter) conversionHint;
 			param = param.nestedIfOptional();
 			if (Message.class.isAssignableFrom(param.getParameterType())) {
 				param = param.nested();

spring-messaging/src/main/java/org/springframework/messaging/converter/MappingJackson2MessageConverter.java

@@ -285,8 +285,7 @@ public class MappingJackson2MessageConverter extends AbstractMessageConverter {
 	 */
 	@Nullable
 	protected Class<?> getSerializationView(@Nullable Object conversionHint) {
-		if (conversionHint instanceof MethodParameter) {
+		if (conversionHint instanceof MethodParameter param) {
-			MethodParameter param = (MethodParameter) conversionHint;
 			JsonView annotation = (param.getParameterIndex() >= 0 ?
 					param.getParameterAnnotation(JsonView.class) : param.getMethodAnnotation(JsonView.class));
 			if (annotation != null) {

spring-messaging/src/main/java/org/springframework/messaging/handler/CompositeMessageCondition.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -131,10 +131,9 @@ public class CompositeMessageCondition implements MessageCondition<CompositeMess
 		if (this == other) {
 			return true;
 		}
-		if (!(other instanceof CompositeMessageCondition)) {
+		if (!(other instanceof CompositeMessageCondition otherComposite)) {
 			return false;
 		}
-		CompositeMessageCondition otherComposite = (CompositeMessageCondition) other;
 		checkCompatible(otherComposite);
 		List<MessageCondition<?>> otherConditions = otherComposite.getMessageConditions();
 		for (int i = 0; i < this.messageConditions.size(); i++) {

spring-messaging/src/main/java/org/springframework/messaging/handler/HandlerMethod.java

@@ -308,10 +308,9 @@ public class HandlerMethod {
 		if (this == other) {
 			return true;
 		}
-		if (!(other instanceof HandlerMethod)) {
+		if (!(other instanceof HandlerMethod otherMethod)) {
 			return false;
 		}
-		HandlerMethod otherMethod = (HandlerMethod) other;
 		return (this.bean.equals(otherMethod.bean) && this.method.equals(otherMethod.method));
 	}
 

spring-messaging/src/main/java/org/springframework/messaging/handler/annotation/support/MessageMethodArgumentResolver.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -134,8 +134,7 @@ public class MessageMethodArgumentResolver implements HandlerMethodArgumentResol
 
 	private Object convertPayload(Message<?> message, MethodParameter parameter, Class<?> targetPayloadType) {
 		Object result = null;
-		if (this.converter instanceof SmartMessageConverter) {
+		if (this.converter instanceof SmartMessageConverter smartConverter) {
-			SmartMessageConverter smartConverter = (SmartMessageConverter) this.converter;
 			result = smartConverter.fromMessage(message, targetPayloadType, parameter);
 		}
 		else if (this.converter != null) {

spring-messaging/src/main/java/org/springframework/messaging/handler/annotation/support/PayloadMethodArgumentResolver.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -133,8 +133,7 @@ public class PayloadMethodArgumentResolver implements HandlerMethodArgumentResol
 			return payload;
 		}
 		else {
-			if (this.converter instanceof SmartMessageConverter) {
+			if (this.converter instanceof SmartMessageConverter smartConverter) {
-				SmartMessageConverter smartConverter = (SmartMessageConverter) this.converter;
 				payload = smartConverter.fromMessage(message, targetClass, parameter);
 			}
 			else {

spring-messaging/src/main/java/org/springframework/messaging/handler/invocation/AbstractMethodMessageHandler.java

@@ -478,8 +478,7 @@ public abstract class AbstractMethodMessageHandler<T>
 		if (CollectionUtils.isEmpty(this.destinationPrefixes)) {
 			return destination;
 		}
-		for (int i = 0; i < this.destinationPrefixes.size(); i++) {
+		for (String prefix : this.destinationPrefixes) {
-			String prefix = this.destinationPrefixes.get(i);
 			if (destination.startsWith(prefix)) {
 				return destination.substring(prefix.length());
 			}

spring-messaging/src/main/java/org/springframework/messaging/handler/invocation/HandlerMethodReturnValueHandlerComposite.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -104,8 +104,7 @@ public class HandlerMethodReturnValueHandlerComposite implements AsyncHandlerMet
 	@SuppressWarnings("ForLoopReplaceableByForEach")
 	@Nullable
 	private HandlerMethodReturnValueHandler getReturnValueHandler(MethodParameter returnType) {
-		for (int i = 0; i < this.returnValueHandlers.size(); i++) {
+		for (HandlerMethodReturnValueHandler handler : this.returnValueHandlers) {
-			HandlerMethodReturnValueHandler handler = this.returnValueHandlers.get(i);
 			if (handler.supportsReturnType(returnType)) {
 				return handler;
 			}

spring-messaging/src/main/java/org/springframework/messaging/handler/invocation/reactive/AbstractMethodMessageHandler.java

@@ -512,7 +512,7 @@ public abstract class AbstractMethodMessageHandler<T>
 		for (T mapping : mappingsToCheck) {
 			T match = getMatchingMapping(mapping, message);
 			if (match != null) {
-				matches.add(new Match<T>(match, this.handlerMethods.get(mapping)));
+				matches.add(new Match<>(match, this.handlerMethods.get(mapping)));
 			}
 		}
 	}

spring-messaging/src/main/java/org/springframework/messaging/handler/invocation/reactive/HandlerMethodReturnValueHandlerComposite.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -95,8 +95,7 @@ public class HandlerMethodReturnValueHandlerComposite implements HandlerMethodRe
 	@SuppressWarnings("ForLoopReplaceableByForEach")
 	@Nullable
 	private HandlerMethodReturnValueHandler getReturnValueHandler(MethodParameter returnType) {
-		for (int i = 0; i < this.returnValueHandlers.size(); i++) {
+		for (HandlerMethodReturnValueHandler handler : this.returnValueHandlers) {
-			HandlerMethodReturnValueHandler handler = this.returnValueHandlers.get(i);
 			if (handler.supportsReturnType(returnType)) {
 				return handler;
 			}

spring-messaging/src/main/java/org/springframework/messaging/handler/invocation/reactive/InvocableHandlerMethod.java

@@ -54,7 +54,7 @@ public class InvocableHandlerMethod extends HandlerMethod {
 	private static final Object NO_ARG_VALUE = new Object();
 
 
-	private HandlerMethodArgumentResolverComposite resolvers = new HandlerMethodArgumentResolverComposite();
+	private final HandlerMethodArgumentResolverComposite resolvers = new HandlerMethodArgumentResolverComposite();
 
 	private ParameterNameDiscoverer parameterNameDiscoverer = new DefaultParameterNameDiscoverer();
 
@@ -206,8 +206,7 @@ public class InvocableHandlerMethod extends HandlerMethod {
 				return true;
 			}
 			Type parameterType = returnType.getGenericParameterType();
-			if (parameterType instanceof ParameterizedType) {
+			if (parameterType instanceof ParameterizedType type) {
-				ParameterizedType type = (ParameterizedType) parameterType;
 				if (type.getActualTypeArguments().length == 1) {
 					return Void.class.equals(type.getActualTypeArguments()[0]);
 				}

spring-messaging/src/main/java/org/springframework/messaging/rsocket/DefaultRSocketRequesterBuilder.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -90,9 +90,9 @@ final class DefaultRSocketRequesterBuilder implements RSocketRequester.Builder {
 	@Nullable
 	private RSocketStrategies strategies;
 
-	private List<Consumer<RSocketStrategies.Builder>> strategiesConfigurers = new ArrayList<>();
+	private final List<Consumer<RSocketStrategies.Builder>> strategiesConfigurers = new ArrayList<>();
 
-	private List<RSocketConnectorConfigurer> rsocketConnectorConfigurers = new ArrayList<>();
+	private final List<RSocketConnectorConfigurer> rsocketConnectorConfigurers = new ArrayList<>();
 
 
 	@Override

spring-messaging/src/main/java/org/springframework/messaging/simp/annotation/support/SendToMethodReturnValueHandler.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -28,6 +28,7 @@ import org.springframework.lang.Nullable;
 import org.springframework.messaging.Message;
 import org.springframework.messaging.MessageChannel;
 import org.springframework.messaging.MessageHeaders;
+import org.springframework.messaging.core.AbstractMessageSendingTemplate;
 import org.springframework.messaging.handler.DestinationPatternsMessageCondition;
 import org.springframework.messaging.handler.annotation.SendTo;
 import org.springframework.messaging.handler.annotation.support.DestinationVariableMethodArgumentResolver;
@@ -35,7 +36,6 @@ import org.springframework.messaging.handler.invocation.HandlerMethodReturnValue
 import org.springframework.messaging.simp.SimpMessageHeaderAccessor;
 import org.springframework.messaging.simp.SimpMessageSendingOperations;
 import org.springframework.messaging.simp.SimpMessageType;
-import org.springframework.messaging.simp.SimpMessagingTemplate;
 import org.springframework.messaging.simp.annotation.SendToUser;
 import org.springframework.messaging.simp.user.DestinationUserNameProvider;
 import org.springframework.messaging.support.MessageHeaderInitializer;
@@ -68,7 +68,7 @@ public class SendToMethodReturnValueHandler implements HandlerMethodReturnValueH
 
 	private String defaultUserDestinationPrefix = "/queue";
 
-	private PropertyPlaceholderHelper placeholderHelper = new PropertyPlaceholderHelper("{", "}", null, false);
+	private final PropertyPlaceholderHelper placeholderHelper = new PropertyPlaceholderHelper("{", "}", null, false);
 
 	@Nullable
 	private MessageHeaderInitializer headerInitializer;
@@ -244,7 +244,7 @@ public class SendToMethodReturnValueHandler implements HandlerMethodReturnValueH
 		if (sessionId != null) {
 			headerAccessor.setSessionId(sessionId);
 		}
-		headerAccessor.setHeader(SimpMessagingTemplate.CONVERSION_HINT_HEADER, returnType);
+		headerAccessor.setHeader(AbstractMessageSendingTemplate.CONVERSION_HINT_HEADER, returnType);
 		headerAccessor.setLeaveMutable(true);
 		return headerAccessor.getMessageHeaders();
 	}

spring-messaging/src/main/java/org/springframework/messaging/simp/annotation/support/SubscriptionMethodReturnValueHandler.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -22,13 +22,13 @@ import org.springframework.core.MethodParameter;
 import org.springframework.lang.Nullable;
 import org.springframework.messaging.Message;
 import org.springframework.messaging.MessageHeaders;
+import org.springframework.messaging.core.AbstractMessageSendingTemplate;
 import org.springframework.messaging.core.MessageSendingOperations;
 import org.springframework.messaging.handler.annotation.SendTo;
 import org.springframework.messaging.handler.invocation.HandlerMethodReturnValueHandler;
 import org.springframework.messaging.simp.SimpLogging;
 import org.springframework.messaging.simp.SimpMessageHeaderAccessor;
 import org.springframework.messaging.simp.SimpMessageType;
-import org.springframework.messaging.simp.SimpMessagingTemplate;
 import org.springframework.messaging.simp.annotation.SendToUser;
 import org.springframework.messaging.simp.annotation.SubscribeMapping;
 import org.springframework.messaging.support.MessageHeaderInitializer;
@@ -141,7 +141,7 @@ public class SubscriptionMethodReturnValueHandler implements HandlerMethodReturn
 			accessor.setSessionId(sessionId);
 		}
 		accessor.setSubscriptionId(subscriptionId);
-		accessor.setHeader(SimpMessagingTemplate.CONVERSION_HINT_HEADER, returnType);
+		accessor.setHeader(AbstractMessageSendingTemplate.CONVERSION_HINT_HEADER, returnType);
 		accessor.setLeaveMutable(true);
 		return accessor.getMessageHeaders();
 	}

spring-messaging/src/main/java/org/springframework/messaging/simp/broker/AbstractBrokerMessageHandler.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -67,7 +67,7 @@ public abstract class AbstractBrokerMessageHandler
 	@Nullable
 	private ApplicationEventPublisher eventPublisher;
 
-	private AtomicBoolean brokerAvailable = new AtomicBoolean();
+	private final AtomicBoolean brokerAvailable = new AtomicBoolean();
 
 	private final BrokerAvailabilityEvent availableEvent = new BrokerAvailabilityEvent(true, this);
 

spring-messaging/src/main/java/org/springframework/messaging/simp/broker/DefaultSubscriptionRegistry.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -41,6 +41,7 @@ import org.springframework.messaging.Message;
 import org.springframework.messaging.MessageHeaders;
 import org.springframework.messaging.simp.SimpMessageHeaderAccessor;
 import org.springframework.messaging.support.MessageHeaderAccessor;
+import org.springframework.messaging.support.NativeMessageHeaderAccessor;
 import org.springframework.util.AntPathMatcher;
 import org.springframework.util.Assert;
 import org.springframework.util.LinkedMultiValueMap;
@@ -162,7 +163,7 @@ public class DefaultSubscriptionRegistry extends AbstractSubscriptionRegistry {
 		if (getSelectorHeaderName() == null) {
 			return null;
 		}
-		String selector = SimpMessageHeaderAccessor.getFirstNativeHeader(getSelectorHeaderName(), headers);
+		String selector = NativeMessageHeaderAccessor.getFirstNativeHeader(getSelectorHeaderName(), headers);
 		if (selector == null) {
 			return null;
 		}
@@ -509,8 +510,7 @@ public class DefaultSubscriptionRegistry extends AbstractSubscriptionRegistry {
 			if (target instanceof Message) {
 				value = name.equals("headers") ? ((Message) target).getHeaders() : null;
 			}
-			else if (target instanceof MessageHeaders) {
+			else if (target instanceof MessageHeaders headers) {
-				MessageHeaders headers = (MessageHeaders) target;
 				SimpMessageHeaderAccessor accessor =
 						MessageHeaderAccessor.getAccessor(headers, SimpMessageHeaderAccessor.class);
 				Assert.state(accessor != null, "No SimpMessageHeaderAccessor");

spring-messaging/src/main/java/org/springframework/messaging/simp/broker/OrderedMessageChannelDecorator.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -154,8 +154,7 @@ public class OrderedMessageChannelDecorator implements MessageChannel {
 				execChannel.addInterceptor(0, new CallbackInterceptor());
 			}
 		}
-		else if (channel instanceof ExecutorSubscribableChannel) {
+		else if (channel instanceof ExecutorSubscribableChannel execChannel) {
-			ExecutorSubscribableChannel execChannel = (ExecutorSubscribableChannel) channel;
 			execChannel.getInterceptors().stream().filter(i -> i instanceof CallbackInterceptor)
 					.findFirst().map(execChannel::removeInterceptor);
 

spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/StompBrokerRelayMessageHandler.java

@@ -657,6 +657,7 @@ public class StompBrokerRelayMessageHandler extends AbstractBrokerMessageHandler
 		}
 
 
+		@Override
 		public String getSessionId() {
 			return this.sessionId;
 		}
@@ -984,6 +985,7 @@ public class StompBrokerRelayMessageHandler extends AbstractBrokerMessageHandler
 			sendSystemSubscriptions();
 		}
 
+		@Override
 		protected void initHeartbeats(StompHeaderAccessor connectedHeaders) {
 			TcpConnection<byte[]> con = getTcpConnection();
 			Assert.state(con != null, "No TcpConnection available");

spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/StompEncoder.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -58,7 +58,7 @@ public class StompEncoder  {
 
 	@SuppressWarnings("serial")
 	private final Map<String, byte[]> headerKeyUpdateCache =
-			new LinkedHashMap<String, byte[]>(HEADER_KEY_CACHE_LIMIT, 0.75f, true) {
+			new LinkedHashMap<>(HEADER_KEY_CACHE_LIMIT, 0.75f, true) {
 				@Override
 				protected boolean removeEldestEntry(Map.Entry<String, byte[]> eldest) {
 					if (size() > HEADER_KEY_CACHE_LIMIT) {
@@ -236,22 +236,24 @@ public class StompEncoder  {
 
 		private int size;
 
+		@Override
 		public void add(byte[] bytes) {
 			this.size += bytes.length;
 			super.add(bytes);
 		}
 
+		@Override
 		public void add(byte b) {
 			this.size++;
 			super.add(b);
 		}
 
+		@Override
 		public byte[] toByteArray() {
 			byte[] result = new byte[this.size];
 			int position = 0;
 			for (Object o : this) {
-				if (o instanceof byte[]) {
+				if (o instanceof byte[] src) {
-					byte[] src = (byte[]) o;
 					System.arraycopy(src, 0, result, position, src.length);
 					position += src.length;
 				}

spring-messaging/src/main/java/org/springframework/messaging/simp/user/MultiServerUserRegistry.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -275,7 +275,7 @@ public class MultiServerUserRegistry implements SimpUserRegistry, SmartApplicati
 		private String name = "";
 
 		// User sessions from "this" registry only (i.e. one server)
-		private Set<TransferSimpSession> sessions;
+		private final Set<TransferSimpSession> sessions;
 
 		// Cross-server session lookup (e.g. user connected to multiple servers)
 		@Nullable
@@ -535,10 +535,9 @@ public class MultiServerUserRegistry implements SimpUserRegistry, SmartApplicati
 			if (this == other) {
 				return true;
 			}
-			if (!(other instanceof SimpSubscription)) {
+			if (!(other instanceof SimpSubscription otherSubscription)) {
 				return false;
 			}
-			SimpSubscription otherSubscription = (SimpSubscription) other;
 			return (getId().equals(otherSubscription.getId()) &&
 					ObjectUtils.nullSafeEquals(getSession(), otherSubscription.getSession()));
 		}

spring-messaging/src/main/java/org/springframework/messaging/simp/user/UserDestinationMessageHandler.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -34,7 +34,9 @@ import org.springframework.messaging.simp.SimpMessageHeaderAccessor;
 import org.springframework.messaging.simp.SimpMessageType;
 import org.springframework.messaging.simp.SimpMessagingTemplate;
 import org.springframework.messaging.support.MessageBuilder;
+import org.springframework.messaging.support.MessageHeaderAccessor;
 import org.springframework.messaging.support.MessageHeaderInitializer;
+import org.springframework.messaging.support.NativeMessageHeaderAccessor;
 import org.springframework.util.Assert;
 import org.springframework.util.StringUtils;
 
@@ -258,7 +260,7 @@ public class UserDestinationMessageHandler implements MessageHandler, SmartLifec
 				return message;
 			}
 			SimpMessageHeaderAccessor accessor =
-					SimpMessageHeaderAccessor.getAccessor(message, SimpMessageHeaderAccessor.class);
+					MessageHeaderAccessor.getAccessor(message, SimpMessageHeaderAccessor.class);
 			Assert.state(accessor != null, "No SimpMessageHeaderAccessor");
 			if (accessor.getSessionId() == null) {
 				// Our own broadcast
@@ -284,7 +286,7 @@ public class UserDestinationMessageHandler implements MessageHandler, SmartLifec
 
 		public void handleUnresolved(Message<?> message) {
 			MessageHeaders headers = message.getHeaders();
-			if (SimpMessageHeaderAccessor.getFirstNativeHeader(
+			if (NativeMessageHeaderAccessor.getFirstNativeHeader(
 					SimpMessageHeaderAccessor.ORIGINAL_DESTINATION, headers) != null) {
 				// Re-broadcast
 				return;

spring-messaging/src/main/java/org/springframework/messaging/support/MessageHeaderAccessor.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -495,14 +495,12 @@ public class MessageHeaderAccessor {
 	}
 
 	protected String getShortPayloadLogMessage(Object payload) {
-		if (payload instanceof String) {
+		if (payload instanceof String payloadText) {
-			String payloadText = (String) payload;
 			return (payloadText.length() < 80) ?
 				" payload=" + payloadText :
 				" payload=" + payloadText.substring(0, 80) + "...(truncated)";
 		}
-		else if (payload instanceof byte[]) {
+		else if (payload instanceof byte[] bytes) {
-			byte[] bytes = (byte[]) payload;
 			if (isReadableContentType()) {
 				return (bytes.length < 80) ?
 						" payload=" + new String(bytes, getCharset()) :
@@ -524,8 +522,7 @@ public class MessageHeaderAccessor {
 		if (payload instanceof String) {
 			return " payload=" + payload;
 		}
-		else if (payload instanceof byte[]) {
+		else if (payload instanceof byte[] bytes) {
-			byte[] bytes = (byte[]) payload;
 			if (isReadableContentType()) {
 				return " payload=" + new String(bytes, getCharset());
 			}
@@ -601,8 +598,7 @@ public class MessageHeaderAccessor {
 	public static <T extends MessageHeaderAccessor> T getAccessor(
 			MessageHeaders messageHeaders, @Nullable Class<T> requiredType) {
 
-		if (messageHeaders instanceof MutableMessageHeaders) {
+		if (messageHeaders instanceof MutableMessageHeaders mutableHeaders) {
-			MutableMessageHeaders mutableHeaders = (MutableMessageHeaders) messageHeaders;
 			MessageHeaderAccessor headerAccessor = mutableHeaders.getAccessor();
 			if (requiredType == null || requiredType.isInstance(headerAccessor))  {
 				return (T) headerAccessor;