Apply "instanceof pattern matching" in remainder of spring-websocket module

See gh-30067

spring-websocket/src/main/java/org/springframework/web/socket/adapter/AbstractWebSocketSession.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2023 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.
@@ -104,17 +104,17 @@ public abstract class AbstractWebSocketSession<T> implements NativeWebSocketSess
 			logger.trace("Sending " + message + ", " + this);
 		}
 
-		if (message instanceof TextMessage) {
+		if (message instanceof TextMessage textMessage) {
-			sendTextMessage((TextMessage) message);
+			sendTextMessage(textMessage);
 		}
-		else if (message instanceof BinaryMessage) {
+		else if (message instanceof BinaryMessage binaryMessage) {
-			sendBinaryMessage((BinaryMessage) message);
+			sendBinaryMessage(binaryMessage);
 		}
-		else if (message instanceof PingMessage) {
+		else if (message instanceof PingMessage pingMessage) {
-			sendPingMessage((PingMessage) message);
+			sendPingMessage(pingMessage);
 		}
-		else if (message instanceof PongMessage) {
+		else if (message instanceof PongMessage pongMessage) {
-			sendPongMessage((PongMessage) message);
+			sendPongMessage(pongMessage);
 		}
 		else {
 			throw new IllegalStateException("Unexpected WebSocketMessage type: " + message);

spring-websocket/src/main/java/org/springframework/web/socket/adapter/standard/ConvertingEncoderDecoderSupport.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2023 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.
@@ -84,10 +84,8 @@ public abstract class ConvertingEncoderDecoderSupport<T, M> {
 	 * @see jakarta.websocket.Decoder#init(EndpointConfig)
 	 */
 	public void init(EndpointConfig config) {
-		ApplicationContext applicationContext = getApplicationContext();
+		if (getApplicationContext() instanceof ConfigurableApplicationContext cac) {
-		if (applicationContext instanceof ConfigurableApplicationContext) {
+			ConfigurableListableBeanFactory beanFactory = cac.getBeanFactory();
-			ConfigurableListableBeanFactory beanFactory =
-					((ConfigurableApplicationContext) applicationContext).getBeanFactory();
 			beanFactory.autowireBean(this);
 		}
 	}
@@ -194,12 +192,12 @@ public abstract class ConvertingEncoderDecoderSupport<T, M> {
 			return (T) getConversionService().convert(message, getMessageType(), getType());
 		}
 		catch (ConversionException ex) {
-			if (message instanceof String) {
+			if (message instanceof String string) {
-				throw new DecodeException((String) message,
+				throw new DecodeException(string,
 						"Unable to decode websocket message using ConversionService", ex);
 			}
-			if (message instanceof ByteBuffer) {
+			if (message instanceof ByteBuffer byteBuffer) {
-				throw new DecodeException((ByteBuffer) message,
+				throw new DecodeException(byteBuffer,
 						"Unable to decode websocket message using ConversionService", ex);
 			}
 			throw ex;

spring-websocket/src/main/java/org/springframework/web/socket/config/WebSocketMessageBrokerStats.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2021 the original author or authors.
+ * Copyright 2002-2023 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.
@@ -93,13 +93,13 @@ public class WebSocketMessageBrokerStats {
 			return null;
 		}
 		for (SubProtocolHandler handler : this.webSocketHandler.getProtocolHandlers()) {
-			if (handler instanceof StompSubProtocolHandler) {
+			if (handler instanceof StompSubProtocolHandler stompHandler) {
-				return (StompSubProtocolHandler) handler;
+				return stompHandler;
 			}
 		}
 		SubProtocolHandler defaultHandler = this.webSocketHandler.getDefaultProtocolHandler();
-		if (defaultHandler instanceof StompSubProtocolHandler) {
+		if (defaultHandler instanceof StompSubProtocolHandler stompHandler) {
-			return (StompSubProtocolHandler) defaultHandler;
+			return stompHandler;
 		}
 		return null;
 	}
@@ -193,9 +193,8 @@ public class WebSocketMessageBrokerStats {
 		if (this.sockJsTaskScheduler == null) {
 			return "null";
 		}
-		if (this.sockJsTaskScheduler instanceof ThreadPoolTaskScheduler) {
+		if (this.sockJsTaskScheduler instanceof ThreadPoolTaskScheduler threadPoolTaskScheduler) {
-			return getExecutorStatsInfo(((ThreadPoolTaskScheduler) this.sockJsTaskScheduler)
+			return getExecutorStatsInfo(threadPoolTaskScheduler.getScheduledThreadPoolExecutor());
-					.getScheduledThreadPoolExecutor());
 		}
 		return "unknown";
 	}
@@ -205,8 +204,8 @@ public class WebSocketMessageBrokerStats {
 			return "null";
 		}
 
-		if (executor instanceof ThreadPoolTaskExecutor) {
+		if (executor instanceof ThreadPoolTaskExecutor threadPoolTaskScheduler) {
-			executor = ((ThreadPoolTaskExecutor) executor).getThreadPoolExecutor();
+			executor = threadPoolTaskScheduler.getThreadPoolExecutor();
 		}
 
 		if (executor instanceof ThreadPoolExecutor) {

spring-websocket/src/main/java/org/springframework/web/socket/config/annotation/WebMvcStompEndpointRegistry.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2023 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.
@@ -91,10 +91,10 @@ public class WebMvcStompEndpointRegistry implements StompEndpointRegistry {
 
 	private static SubProtocolWebSocketHandler unwrapSubProtocolWebSocketHandler(WebSocketHandler handler) {
 		WebSocketHandler actual = WebSocketHandlerDecorator.unwrap(handler);
-		if (!(actual instanceof SubProtocolWebSocketHandler)) {
+		if (!(actual instanceof SubProtocolWebSocketHandler subProtocolWebSocketHandler)) {
 			throw new IllegalArgumentException("No SubProtocolWebSocketHandler in " + handler);
 		}
-		return (SubProtocolWebSocketHandler) actual;
+		return subProtocolWebSocketHandler;
 	}
 
 

spring-websocket/src/main/java/org/springframework/web/socket/config/annotation/WebSocketMessageBrokerConfigurationSupport.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2023 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.
@@ -137,8 +137,8 @@ public abstract class WebSocketMessageBrokerConfigurationSupport extends Abstrac
 
 		WebSocketMessageBrokerStats stats = new WebSocketMessageBrokerStats();
 		stats.setSubProtocolWebSocketHandler((SubProtocolWebSocketHandler) subProtocolWebSocketHandler);
-		if (stompBrokerRelayMessageHandler instanceof StompBrokerRelayMessageHandler) {
+		if (stompBrokerRelayMessageHandler instanceof StompBrokerRelayMessageHandler sbrmh) {
-			stats.setStompBrokerRelay((StompBrokerRelayMessageHandler) stompBrokerRelayMessageHandler);
+			stats.setStompBrokerRelay(sbrmh);
 		}
 		stats.setInboundChannelExecutor(inboundExecutor);
 		stats.setOutboundChannelExecutor(outboundExecutor);

spring-websocket/src/main/java/org/springframework/web/socket/handler/AbstractWebSocketHandler.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2013 the original author or authors.
+ * Copyright 2002-2023 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.
@@ -39,14 +39,14 @@ public abstract class AbstractWebSocketHandler implements WebSocketHandler {
 
 	@Override
 	public void handleMessage(WebSocketSession session, WebSocketMessage<?> message) throws Exception {
-		if (message instanceof TextMessage) {
+		if (message instanceof TextMessage textMessage) {
-			handleTextMessage(session, (TextMessage) message);
+			handleTextMessage(session, textMessage);
 		}
-		else if (message instanceof BinaryMessage) {
+		else if (message instanceof BinaryMessage binaryMessage) {
-			handleBinaryMessage(session, (BinaryMessage) message);
+			handleBinaryMessage(session, binaryMessage);
 		}
-		else if (message instanceof PongMessage) {
+		else if (message instanceof PongMessage pongMessage) {
-			handlePongMessage(session, (PongMessage) message);
+			handlePongMessage(session, pongMessage);
 		}
 		else {
 			throw new IllegalStateException("Unexpected WebSocket message type: " + message);

spring-websocket/src/main/java/org/springframework/web/socket/handler/BeanCreatingHandlerProvider.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2023 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.
@@ -48,8 +48,8 @@ public class BeanCreatingHandlerProvider<T> implements BeanFactoryAware {
 
 	@Override
 	public void setBeanFactory(BeanFactory beanFactory) {
-		if (beanFactory instanceof AutowireCapableBeanFactory) {
+		if (beanFactory instanceof AutowireCapableBeanFactory autowireCapableBeanFactory) {
-			this.beanFactory = (AutowireCapableBeanFactory) beanFactory;
+			this.beanFactory = autowireCapableBeanFactory;
 		}
 	}
 

spring-websocket/src/main/java/org/springframework/web/socket/handler/WebSocketHandlerDecorator.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2013 the original author or authors.
+ * Copyright 2002-2023 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.
@@ -50,15 +50,15 @@ public class WebSocketHandlerDecorator implements WebSocketHandler {
 
 	public WebSocketHandler getLastHandler() {
 		WebSocketHandler result = this.delegate;
-		while (result instanceof WebSocketHandlerDecorator) {
+		while (result instanceof WebSocketHandlerDecorator webSocketHandlerDecorator) {
-			result = ((WebSocketHandlerDecorator) result).getDelegate();
+			result = webSocketHandlerDecorator.getDelegate();
 		}
 		return result;
 	}
 
 	public static WebSocketHandler unwrap(WebSocketHandler handler) {
-		if (handler instanceof WebSocketHandlerDecorator) {
+		if (handler instanceof WebSocketHandlerDecorator webSocketHandlerDecorator) {
-			return ((WebSocketHandlerDecorator) handler).getLastHandler();
+			return webSocketHandlerDecorator.getLastHandler();
 		}
 		else {
 			return handler;

spring-websocket/src/main/java/org/springframework/web/socket/handler/WebSocketSessionDecorator.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2023 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.
@@ -59,15 +59,15 @@ public class WebSocketSessionDecorator implements WebSocketSession {
 
 	public WebSocketSession getLastSession() {
 		WebSocketSession result = this.delegate;
-		while (result instanceof WebSocketSessionDecorator) {
+		while (result instanceof WebSocketSessionDecorator webSocketSessionDecorator) {
-			result = ((WebSocketSessionDecorator) result).getDelegate();
+			result = webSocketSessionDecorator.getDelegate();
 		}
 		return result;
 	}
 
 	public static WebSocketSession unwrap(WebSocketSession session) {
-		if (session instanceof WebSocketSessionDecorator) {
+		if (session instanceof WebSocketSessionDecorator webSocketSessionDecorator) {
-			return ((WebSocketSessionDecorator) session).getLastSession();
+			return webSocketSessionDecorator.getLastSession();
 		}
 		else {
 			return session;

spring-websocket/src/main/java/org/springframework/web/socket/messaging/StompSubProtocolHandler.java

@@ -230,11 +230,11 @@ public class StompSubProtocolHandler implements SubProtocolHandler, ApplicationE
 		List<Message<byte[]>> messages;
 		try {
 			ByteBuffer byteBuffer;
-			if (webSocketMessage instanceof TextMessage) {
+			if (webSocketMessage instanceof TextMessage textMessage) {
-				byteBuffer = ByteBuffer.wrap(((TextMessage) webSocketMessage).asBytes());
+				byteBuffer = ByteBuffer.wrap(textMessage.asBytes());
 			}
-			else if (webSocketMessage instanceof BinaryMessage) {
+			else if (webSocketMessage instanceof BinaryMessage binaryMessage) {
-				byteBuffer = ((BinaryMessage) webSocketMessage).getPayload();
+				byteBuffer = binaryMessage.getPayload();
 			}
 			else {
 				return;
@@ -398,8 +398,8 @@ public class StompSubProtocolHandler implements SubProtocolHandler, ApplicationE
 			return this.immutableMessageInterceptorPresent;
 		}
 
-		if (channel instanceof AbstractMessageChannel) {
+		if (channel instanceof AbstractMessageChannel abstractMessageChannel) {
-			for (ChannelInterceptor interceptor : ((AbstractMessageChannel) channel).getInterceptors()) {
+			for (ChannelInterceptor interceptor : abstractMessageChannel.getInterceptors()) {
 				if (interceptor instanceof ImmutableMessageChannelInterceptor) {
 					this.immutableMessageInterceptorPresent = true;
 					return true;
@@ -520,8 +520,8 @@ public class StompSubProtocolHandler implements SubProtocolHandler, ApplicationE
 
 	private StompHeaderAccessor getStompHeaderAccessor(Message<?> message) {
 		MessageHeaderAccessor accessor = MessageHeaderAccessor.getAccessor(message, MessageHeaderAccessor.class);
-		if (accessor instanceof StompHeaderAccessor) {
+		if (accessor instanceof StompHeaderAccessor stompHeaderAccessor) {
-			return (StompHeaderAccessor) accessor;
+			return stompHeaderAccessor;
 		}
 		else {
 			StompHeaderAccessor stompAccessor = StompHeaderAccessor.wrap(message);
@@ -614,8 +614,8 @@ public class StompSubProtocolHandler implements SubProtocolHandler, ApplicationE
 		long[] heartbeat = accessor.getHeartbeat();
 		if (heartbeat[1] > 0) {
 			session = WebSocketSessionDecorator.unwrap(session);
-			if (session instanceof SockJsSession) {
+			if (session instanceof SockJsSession sockJsSession) {
-				((SockJsSession) session).disableHeartbeat();
+				sockJsSession.disableHeartbeat();
 			}
 		}
 

spring-websocket/src/main/java/org/springframework/web/socket/messaging/WebSocketStompClient.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2023 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.
@@ -178,8 +178,8 @@ public class WebSocketStompClient extends StompClientSupport implements SmartLif
 	public void start() {
 		if (!isRunning()) {
 			this.running = true;
-			if (getWebSocketClient() instanceof Lifecycle) {
+			if (getWebSocketClient() instanceof Lifecycle lifecycle) {
-				((Lifecycle) getWebSocketClient()).start();
+				lifecycle.start();
 			}
 		}
 
@@ -189,8 +189,8 @@ public class WebSocketStompClient extends StompClientSupport implements SmartLif
 	public void stop() {
 		if (isRunning()) {
 			this.running = false;
-			if (getWebSocketClient() instanceof Lifecycle) {
+			if (getWebSocketClient() instanceof Lifecycle lifecycle) {
-				((Lifecycle) getWebSocketClient()).stop();
+				lifecycle.stop();
 			}
 		}
 	}
@@ -554,11 +554,11 @@ public class WebSocketStompClient extends StompClientSupport implements SmartLif
 		public List<Message<byte[]>> decode(WebSocketMessage<?> webSocketMessage) {
 			List<Message<byte[]>> result = Collections.emptyList();
 			ByteBuffer byteBuffer;
-			if (webSocketMessage instanceof TextMessage) {
+			if (webSocketMessage instanceof TextMessage textMessage) {
-				byteBuffer = ByteBuffer.wrap(((TextMessage) webSocketMessage).asBytes());
+				byteBuffer = ByteBuffer.wrap(textMessage.asBytes());
 			}
-			else if (webSocketMessage instanceof BinaryMessage) {
+			else if (webSocketMessage instanceof BinaryMessage binaryMessage) {
-				byteBuffer = ((BinaryMessage) webSocketMessage).getPayload();
+				byteBuffer = binaryMessage.getPayload();
 			}
 			else {
 				return result;

spring-websocket/src/main/java/org/springframework/web/socket/server/standard/WebLogicRequestUpgradeStrategy.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2023 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.
@@ -94,8 +94,8 @@ public class WebLogicRequestUpgradeStrategy extends AbstractTyrusRequestUpgradeS
 	}
 
 	private static Object getNativeRequest(ServletRequest request) {
-		while (request instanceof ServletRequestWrapper) {
+		while (request instanceof ServletRequestWrapper wrapper) {
-			request = ((ServletRequestWrapper) request).getRequest();
+			request = wrapper.getRequest();
 		}
 		return request;
 	}

spring-websocket/src/main/java/org/springframework/web/socket/server/support/AbstractHandshakeHandler.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2023 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.
@@ -176,8 +176,8 @@ public abstract class AbstractHandshakeHandler implements HandshakeHandler, Life
 	}
 
 	protected void doStart() {
-		if (this.requestUpgradeStrategy instanceof Lifecycle) {
+		if (this.requestUpgradeStrategy instanceof Lifecycle lifecycle) {
-			((Lifecycle) this.requestUpgradeStrategy).start();
+			lifecycle.start();
 		}
 	}
 
@@ -190,8 +190,8 @@ public abstract class AbstractHandshakeHandler implements HandshakeHandler, Life
 	}
 
 	protected void doStop() {
-		if (this.requestUpgradeStrategy instanceof Lifecycle) {
+		if (this.requestUpgradeStrategy instanceof Lifecycle lifecycle) {
-			((Lifecycle) this.requestUpgradeStrategy).stop();
+			lifecycle.stop();
 		}
 	}
 
@@ -349,8 +349,8 @@ public abstract class AbstractHandshakeHandler implements HandshakeHandler, Life
 	protected final List<String> determineHandlerSupportedProtocols(WebSocketHandler handler) {
 		WebSocketHandler handlerToCheck = WebSocketHandlerDecorator.unwrap(handler);
 		List<String> subProtocols = null;
-		if (handlerToCheck instanceof SubProtocolCapable) {
+		if (handlerToCheck instanceof SubProtocolCapable subProtocolCapable) {
-			subProtocols = ((SubProtocolCapable) handlerToCheck).getSubProtocols();
+			subProtocols = subProtocolCapable.getSubProtocols();
 		}
 		return (subProtocols != null ? subProtocols : Collections.emptyList());
 	}

spring-websocket/src/main/java/org/springframework/web/socket/server/support/DefaultHandshakeHandler.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2023 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.
@@ -43,8 +43,8 @@ public class DefaultHandshakeHandler extends AbstractHandshakeHandler implements
 	@Override
 	public void setServletContext(ServletContext servletContext) {
 		RequestUpgradeStrategy strategy = getRequestUpgradeStrategy();
-		if (strategy instanceof ServletContextAware) {
+		if (strategy instanceof ServletContextAware servletContextAware) {
-			((ServletContextAware) strategy).setServletContext(servletContext);
+			servletContextAware.setServletContext(servletContext);
 		}
 	}
 

spring-websocket/src/main/java/org/springframework/web/socket/server/support/WebSocketHandlerMapping.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2021 the original author or authors.
+ * Copyright 2002-2023 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.
@@ -61,8 +61,8 @@ public class WebSocketHandlerMapping extends SimpleUrlHandlerMapping implements
 	@Override
 	protected void initServletContext(ServletContext servletContext) {
 		for (Object handler : getUrlMap().values()) {
-			if (handler instanceof ServletContextAware) {
+			if (handler instanceof ServletContextAware servletContextAware) {
-				((ServletContextAware) handler).setServletContext(servletContext);
+				servletContextAware.setServletContext(servletContext);
 			}
 		}
 	}
@@ -73,8 +73,8 @@ public class WebSocketHandlerMapping extends SimpleUrlHandlerMapping implements
 		if (!isRunning()) {
 			this.running = true;
 			for (Object handler : getUrlMap().values()) {
-				if (handler instanceof Lifecycle) {
+				if (handler instanceof Lifecycle lifecycle) {
-					((Lifecycle) handler).start();
+					lifecycle.start();
 				}
 			}
 		}
@@ -85,8 +85,8 @@ public class WebSocketHandlerMapping extends SimpleUrlHandlerMapping implements
 		if (isRunning()) {
 			this.running = false;
 			for (Object handler : getUrlMap().values()) {
-				if (handler instanceof Lifecycle) {
+				if (handler instanceof Lifecycle lifecycle) {
-					((Lifecycle) handler).stop();
+					lifecycle.stop();
 				}
 			}
 		}
@@ -106,8 +106,7 @@ public class WebSocketHandlerMapping extends SimpleUrlHandlerMapping implements
 	}
 
 	private boolean matchWebSocketUpgrade(@Nullable Object handler, HttpServletRequest request) {
-		handler = (handler instanceof HandlerExecutionChain ?
+		handler = (handler instanceof HandlerExecutionChain chain ? chain.getHandler() : handler);
-				((HandlerExecutionChain) handler).getHandler() : handler);
 		if (this.webSocketUpgradeMatch && handler instanceof WebSocketHttpRequestHandler) {
 			String header = request.getHeader(HttpHeaders.UPGRADE);
 			return (request.getMethod().equals("GET") &&

spring-websocket/src/main/java/org/springframework/web/socket/server/support/WebSocketHttpRequestHandler.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2023 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.
@@ -124,8 +124,8 @@ public class WebSocketHttpRequestHandler implements HttpRequestHandler, Lifecycl
 
 	@Override
 	public void setServletContext(ServletContext servletContext) {
-		if (this.handshakeHandler instanceof ServletContextAware) {
+		if (this.handshakeHandler instanceof ServletContextAware servletContextAware) {
-			((ServletContextAware) this.handshakeHandler).setServletContext(servletContext);
+			servletContextAware.setServletContext(servletContext);
 		}
 	}
 
@@ -134,8 +134,8 @@ public class WebSocketHttpRequestHandler implements HttpRequestHandler, Lifecycl
 	public void start() {
 		if (!isRunning()) {
 			this.running = true;
-			if (this.handshakeHandler instanceof Lifecycle) {
+			if (this.handshakeHandler instanceof Lifecycle lifecycle) {
-				((Lifecycle) this.handshakeHandler).start();
+				lifecycle.start();
 			}
 		}
 	}
@@ -144,8 +144,8 @@ public class WebSocketHttpRequestHandler implements HttpRequestHandler, Lifecycl
 	public void stop() {
 		if (isRunning()) {
 			this.running = false;
-			if (this.handshakeHandler instanceof Lifecycle) {
+			if (this.handshakeHandler instanceof Lifecycle lifecycle) {
-				((Lifecycle) this.handshakeHandler).stop();
+				lifecycle.stop();
 			}
 		}
 	}

spring-websocket/src/main/java/org/springframework/web/socket/sockjs/client/AbstractClientSockJsSession.java

@@ -155,14 +155,14 @@ public abstract class AbstractClientSockJsSession implements WebSocketSession {
 
 	@Override
 	public final void sendMessage(WebSocketMessage<?> message) throws IOException {
-		if (!(message instanceof TextMessage)) {
+		if (!(message instanceof TextMessage textMessage)) {
 			throw new IllegalArgumentException(this + " supports text messages only.");
 		}
 		if (this.state != State.OPEN) {
 			throw new IllegalStateException(this + " is not open: current state " + this.state);
 		}
 
-		String payload = ((TextMessage) message).getPayload();
+		String payload = textMessage.getPayload();
 		payload = getMessageCodec().encode(payload);
 		payload = payload.substring(1);  // the client-side doesn't need message framing (letter "a")
 

spring-websocket/src/main/java/org/springframework/web/socket/sockjs/client/RestTemplateXhrTransport.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2023 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.
@@ -183,8 +183,8 @@ public class RestTemplateXhrTransport extends AbstractXhrTransport {
 		public void doWithRequest(ClientHttpRequest request) throws IOException {
 			request.getHeaders().putAll(this.headers);
 			if (this.body != null) {
-				if (request instanceof StreamingHttpOutputMessage) {
+				if (request instanceof StreamingHttpOutputMessage streamingOutputMessage) {
-					((StreamingHttpOutputMessage) request).setBody(outputStream ->
+					streamingOutputMessage.setBody(outputStream ->
 							StreamUtils.copy(this.body, SockJsFrame.CHARSET, outputStream));
 				}
 				else {

spring-websocket/src/main/java/org/springframework/web/socket/sockjs/client/WebSocketTransport.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2023 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 +95,8 @@ public class WebSocketTransport implements Transport, Lifecycle {
 	@Override
 	public void start() {
 		if (!isRunning()) {
-			if (this.webSocketClient instanceof Lifecycle) {
+			if (this.webSocketClient instanceof Lifecycle lifecycle) {
-				((Lifecycle) this.webSocketClient).start();
+				lifecycle.start();
 			}
 			else {
 				this.running = true;
@@ -107,8 +107,8 @@ public class WebSocketTransport implements Transport, Lifecycle {
 	@Override
 	public void stop() {
 		if (isRunning()) {
-			if (this.webSocketClient instanceof Lifecycle) {
+			if (this.webSocketClient instanceof Lifecycle lifecycle) {
-				((Lifecycle) this.webSocketClient).stop();
+				lifecycle.stop();
 			}
 			else {
 				this.running = false;
@@ -118,8 +118,8 @@ public class WebSocketTransport implements Transport, Lifecycle {
 
 	@Override
 	public boolean isRunning() {
-		if (this.webSocketClient instanceof Lifecycle) {
+		if (this.webSocketClient instanceof Lifecycle lifecycle) {
-			return ((Lifecycle) this.webSocketClient).isRunning();
+			return lifecycle.isRunning();
 		}
 		else {
 			return this.running;

spring-websocket/src/main/java/org/springframework/web/socket/sockjs/support/SockJsHttpRequestHandler.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2023 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.
@@ -91,8 +91,8 @@ public class SockJsHttpRequestHandler
 
 	@Override
 	public void setServletContext(ServletContext servletContext) {
-		if (this.sockJsService instanceof ServletContextAware) {
+		if (this.sockJsService instanceof ServletContextAware servletContextAware) {
-			((ServletContextAware) this.sockJsService).setServletContext(servletContext);
+			servletContextAware.setServletContext(servletContext);
 		}
 	}
 
@@ -101,8 +101,8 @@ public class SockJsHttpRequestHandler
 	public void start() {
 		if (!isRunning()) {
 			this.running = true;
-			if (this.sockJsService instanceof Lifecycle) {
+			if (this.sockJsService instanceof Lifecycle lifecycle) {
-				((Lifecycle) this.sockJsService).start();
+				lifecycle.start();
 			}
 		}
 	}
@@ -111,8 +111,8 @@ public class SockJsHttpRequestHandler
 	public void stop() {
 		if (isRunning()) {
 			this.running = false;
-			if (this.sockJsService instanceof Lifecycle) {
+			if (this.sockJsService instanceof Lifecycle lifecycle) {
-				((Lifecycle) this.sockJsService).stop();
+				lifecycle.stop();
 			}
 		}
 	}
@@ -147,8 +147,8 @@ public class SockJsHttpRequestHandler
 	@Override
 	@Nullable
 	public CorsConfiguration getCorsConfiguration(HttpServletRequest request) {
-		if (this.sockJsService instanceof CorsConfigurationSource) {
+		if (this.sockJsService instanceof CorsConfigurationSource ccs) {
-			return ((CorsConfigurationSource) this.sockJsService).getCorsConfiguration(request);
+			return ccs.getCorsConfiguration(request);
 		}
 		return null;
 	}

spring-websocket/src/main/java/org/springframework/web/socket/sockjs/transport/TransportHandlingSockJsService.java

@@ -169,8 +169,8 @@ public class TransportHandlingSockJsService extends AbstractSockJsService implem
 		if (!isRunning()) {
 			this.running = true;
 			for (TransportHandler handler : this.handlers.values()) {
-				if (handler instanceof Lifecycle) {
+				if (handler instanceof Lifecycle lifecycle) {
-					((Lifecycle) handler).start();
+					lifecycle.start();
 				}
 			}
 		}
@@ -181,8 +181,8 @@ public class TransportHandlingSockJsService extends AbstractSockJsService implem
 		if (isRunning()) {
 			this.running = false;
 			for (TransportHandler handler : this.handlers.values()) {
-				if (handler instanceof Lifecycle) {
+				if (handler instanceof Lifecycle lifecycle) {
-					((Lifecycle) handler).stop();
+					lifecycle.stop();
 				}
 			}
 		}
@@ -199,7 +199,7 @@ public class TransportHandlingSockJsService extends AbstractSockJsService implem
 			WebSocketHandler handler) throws IOException {
 
 		TransportHandler transportHandler = this.handlers.get(TransportType.WEBSOCKET);
-		if (!(transportHandler instanceof HandshakeHandler)) {
+		if (!(transportHandler instanceof HandshakeHandler handshakeHandler)) {
 			logger.error("No handler configured for raw WebSocket messages");
 			response.setStatusCode(HttpStatus.NOT_FOUND);
 			return;
@@ -213,7 +213,7 @@ public class TransportHandlingSockJsService extends AbstractSockJsService implem
 			if (!chain.applyBeforeHandshake(request, response, attributes)) {
 				return;
 			}
-			((HandshakeHandler) transportHandler).doHandshake(request, response, handler, attributes);
+			handshakeHandler.doHandshake(request, response, handler, attributes);
 			chain.applyAfterHandshake(request, response, null);
 		}
 		catch (HandshakeFailureException ex) {

spring-websocket/src/main/java/org/springframework/web/socket/sockjs/transport/handler/DefaultSockJsService.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2023 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.
@@ -103,9 +103,10 @@ public class DefaultSockJsService extends TransportHandlingSockJsService impleme
 	@Override
 	public void setServletContext(ServletContext servletContext) {
 		for (TransportHandler handler : getTransportHandlers().values()) {
-			if (handler instanceof ServletContextAware) {
+			if (handler instanceof ServletContextAware servletContextAware) {
-				((ServletContextAware) handler).setServletContext(servletContext);
+				servletContextAware.setServletContext(servletContext);
 			}
 		}
 	}
+
 }

spring-websocket/src/main/java/org/springframework/web/socket/sockjs/transport/handler/SockJsWebSocketHandler.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2023 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.
@@ -69,8 +69,8 @@ public class SockJsWebSocketHandler extends TextWebSocketHandler implements SubP
 		this.sockJsSession = sockJsSession;
 
 		webSocketHandler = WebSocketHandlerDecorator.unwrap(webSocketHandler);
-		this.subProtocols = ((webSocketHandler instanceof SubProtocolCapable) ?
+		this.subProtocols = ((webSocketHandler instanceof SubProtocolCapable subProtocolCapable) ?
-				new ArrayList<>(((SubProtocolCapable) webSocketHandler).getSubProtocols()) : Collections.emptyList());
+				new ArrayList<>(subProtocolCapable.getSubProtocols()) : Collections.emptyList());
 	}
 
 	@Override

spring-websocket/src/main/java/org/springframework/web/socket/sockjs/transport/handler/WebSocketTransportHandler.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2023 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.
@@ -73,8 +73,8 @@ public class WebSocketTransportHandler extends AbstractTransportHandler
 
 	@Override
 	public void setServletContext(ServletContext servletContext) {
-		if (this.handshakeHandler instanceof ServletContextAware) {
+		if (this.handshakeHandler instanceof ServletContextAware servletContextAware) {
-			((ServletContextAware) this.handshakeHandler).setServletContext(servletContext);
+			servletContextAware.setServletContext(servletContext);
 		}
 	}
 
@@ -83,8 +83,8 @@ public class WebSocketTransportHandler extends AbstractTransportHandler
 	public void start() {
 		if (!isRunning()) {
 			this.running = true;
-			if (this.handshakeHandler instanceof Lifecycle) {
+			if (this.handshakeHandler instanceof Lifecycle lifecycle) {
-				((Lifecycle) this.handshakeHandler).start();
+				lifecycle.start();
 			}
 		}
 	}
@@ -93,8 +93,8 @@ public class WebSocketTransportHandler extends AbstractTransportHandler
 	public void stop() {
 		if (isRunning()) {
 			this.running = false;
-			if (this.handshakeHandler instanceof Lifecycle) {
+			if (this.handshakeHandler instanceof Lifecycle lifecycle) {
-				((Lifecycle) this.handshakeHandler).stop();
+				lifecycle.stop();
 			}
 		}
 	}

spring-websocket/src/main/java/org/springframework/web/socket/sockjs/transport/session/AbstractHttpSockJsSession.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2023 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.
@@ -278,8 +278,8 @@ public abstract class AbstractHttpSockJsSession extends AbstractSockJsSession {
 	}
 
 	private void disableShallowEtagHeaderFilter(ServerHttpRequest request) {
-		if (request instanceof ServletServerHttpRequest) {
+		if (request instanceof ServletServerHttpRequest servletServerHttpRequest) {
-			ServletRequest servletRequest = ((ServletServerHttpRequest) request).getServletRequest();
+			ServletRequest servletRequest = servletServerHttpRequest.getServletRequest();
 			ShallowEtagHeaderFilter.disableContentCaching(servletRequest);
 		}
 	}

spring-websocket/src/main/java/org/springframework/web/socket/sockjs/transport/session/WebSocketServerSockJsSession.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2023 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.
@@ -139,15 +139,15 @@ public class WebSocketServerSockJsSession extends AbstractSockJsSession implemen
 	@Override
 	public Object getNativeSession() {
 		Assert.state(this.webSocketSession != null, "WebSocketSession not yet initialized");
-		return (this.webSocketSession instanceof NativeWebSocketSession ?
+		return (this.webSocketSession instanceof NativeWebSocketSession nativeWsSession ?
-				((NativeWebSocketSession) this.webSocketSession).getNativeSession() : this.webSocketSession);
+				nativeWsSession.getNativeSession() : this.webSocketSession);
 	}
 
 	@Override
 	@Nullable
 	public <T> T getNativeSession(@Nullable Class<T> requiredType) {
-		return (this.webSocketSession instanceof NativeWebSocketSession ?
+		return (this.webSocketSession instanceof NativeWebSocketSession nativeWsSession ?
-				((NativeWebSocketSession) this.webSocketSession).getNativeSession(requiredType) : null);
+				nativeWsSession.getNativeSession(requiredType) : null);
 	}