Use new Java features (switch expressions, text blocks, new JDK methods)

Closes gh-29747

spring-aop/src/main/java/org/springframework/aop/aspectj/AspectJAdviceParameterNameDiscoverer.java

@@ -244,31 +244,18 @@ public class AspectJAdviceParameterNameDiscoverer implements ParameterNameDiscov
 			int algorithmicStep = STEP_JOIN_POINT_BINDING;
 			while ((this.numberOfRemainingUnboundArguments > 0) && algorithmicStep < STEP_FINISHED) {
 				switch (algorithmicStep++) {
-					case STEP_JOIN_POINT_BINDING:
+					case STEP_JOIN_POINT_BINDING -> {
 						if (!maybeBindThisJoinPoint()) {
 							maybeBindThisJoinPointStaticPart();
 						}
-						break;
+					}
-					case STEP_THROWING_BINDING:
+					case STEP_THROWING_BINDING -> maybeBindThrowingVariable();
-						maybeBindThrowingVariable();
+					case STEP_ANNOTATION_BINDING -> maybeBindAnnotationsFromPointcutExpression();
-						break;
+					case STEP_RETURNING_BINDING -> maybeBindReturningVariable();
-					case STEP_ANNOTATION_BINDING:
+					case STEP_PRIMITIVE_ARGS_BINDING -> maybeBindPrimitiveArgsFromPointcutExpression();
-						maybeBindAnnotationsFromPointcutExpression();
+					case STEP_THIS_TARGET_ARGS_BINDING -> maybeBindThisOrTargetOrArgsFromPointcutExpression();
-						break;
+					case STEP_REFERENCE_PCUT_BINDING -> maybeBindReferencePointcutParameter();
-					case STEP_RETURNING_BINDING:
+					default -> throw new IllegalStateException("Unknown algorithmic step: " + (algorithmicStep - 1));
-						maybeBindReturningVariable();
-						break;
-					case STEP_PRIMITIVE_ARGS_BINDING:
-						maybeBindPrimitiveArgsFromPointcutExpression();
-						break;
-					case STEP_THIS_TARGET_ARGS_BINDING:
-						maybeBindThisOrTargetOrArgsFromPointcutExpression();
-						break;
-					case STEP_REFERENCE_PCUT_BINDING:
-						maybeBindReferencePointcutParameter();
-						break;
-					default:
-						throw new IllegalStateException("Unknown algorithmic step: " + (algorithmicStep - 1));
 				}
 			}
 		}

spring-beans/src/main/java/org/springframework/beans/factory/support/AutowireUtils.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2021 the original author or authors.
+ * Copyright 2002-2022 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.
@@ -128,8 +128,7 @@ abstract class AutowireUtils {
 	 * @return the resolved value
 	 */
 	public static Object resolveAutowiringValue(Object autowiringValue, Class<?> requiredType) {
-		if (autowiringValue instanceof ObjectFactory && !requiredType.isInstance(autowiringValue)) {
+		if (autowiringValue instanceof ObjectFactory<?> factory && !requiredType.isInstance(autowiringValue)) {
-			ObjectFactory<?> factory = (ObjectFactory<?>) autowiringValue;
 			if (autowiringValue instanceof Serializable && requiredType.isInterface()) {
 				autowiringValue = Proxy.newProxyInstance(requiredType.getClassLoader(),
 						new Class<?>[] {requiredType}, new ObjectFactoryDelegatingInvocationHandler(factory));
@@ -275,22 +274,19 @@ abstract class AutowireUtils {
 
 		@Override
 		public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
-			switch (method.getName()) {
+			return switch (method.getName()) {
-				case "equals":
+				case "equals" -> (proxy == args[0]); // Only consider equal when proxies are identical.
-					// Only consider equal when proxies are identical.
+				case "hashCode" -> System.identityHashCode(proxy); // Use hashCode of proxy.
-					return (proxy == args[0]);
+				case "toString" -> this.objectFactory.toString();
-				case "hashCode":
+				default -> {
-					// Use hashCode of proxy.
+					try {
-					return System.identityHashCode(proxy);
+						yield method.invoke(this.objectFactory.getObject(), args);
-				case "toString":
+					}
-					return this.objectFactory.toString();
+					catch (InvocationTargetException ex) {
-			}
+						throw ex.getTargetException();
-			try {
+					}
-				return method.invoke(this.objectFactory.getObject(), args);
+				}
-			}
+			};
-			catch (InvocationTargetException ex) {
-				throw ex.getTargetException();
-			}
 		}
 	}
 

spring-beans/src/main/java/org/springframework/beans/factory/support/StaticListableBeanFactory.java

@@ -365,8 +365,7 @@ public class StaticListableBeanFactory implements ListableBeanFactory {
 		for (Map.Entry<String, Object> entry : this.beans.entrySet()) {
 			String beanName = entry.getKey();
 			Object beanInstance = entry.getValue();
-			if (beanInstance instanceof FactoryBean && !isFactoryType) {
+			if (beanInstance instanceof FactoryBean<?> factoryBean && !isFactoryType) {
-				FactoryBean<?> factoryBean = (FactoryBean<?>) beanInstance;
 				Class<?> objectType = factoryBean.getObjectType();
 				if ((includeNonSingletons || factoryBean.isSingleton()) &&
 						objectType != null && (type == null || type.isAssignableFrom(objectType))) {
@@ -409,9 +408,8 @@ public class StaticListableBeanFactory implements ListableBeanFactory {
 			String beanName = entry.getKey();
 			Object beanInstance = entry.getValue();
 			// Is bean a FactoryBean?
-			if (beanInstance instanceof FactoryBean && !isFactoryType) {
+			if (beanInstance instanceof FactoryBean<?> factory && !isFactoryType) {
 				// Match object created by FactoryBean.
-				FactoryBean<?> factory = (FactoryBean<?>) beanInstance;
 				Class<?> objectType = factory.getObjectType();
 				if ((includeNonSingletons || factory.isSingleton()) &&
 						objectType != null && (type == null || type.isAssignableFrom(objectType))) {

spring-context-support/src/main/java/org/springframework/ui/freemarker/FreeMarkerConfigurationFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2022 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.
@@ -389,16 +389,17 @@ public class FreeMarkerConfigurationFactory {
 	 */
 	@Nullable
 	protected TemplateLoader getAggregateTemplateLoader(List<TemplateLoader> templateLoaders) {
-		switch (templateLoaders.size()) {
+		return switch (templateLoaders.size()) {
-			case 0:
+			case 0 -> {
 				logger.debug("No FreeMarker TemplateLoaders specified");
-				return null;
+				yield null;
-			case 1:
+			}
-				return templateLoaders.get(0);
+			case 1 -> templateLoaders.get(0);
-			default:
+			default -> {
 				TemplateLoader[] loaders = templateLoaders.toArray(new TemplateLoader[0]);
-				return new MultiTemplateLoader(loaders);
+				yield new MultiTemplateLoader(loaders);
-		}
+			}
+		};
 	}
 
 	/**

spring-context/src/main/java/org/springframework/jmx/export/MBeanExporter.java

@@ -587,12 +587,11 @@ public class MBeanExporter extends MBeanRegistrationSupport implements MBeanExpo
 	 */
 	protected ObjectName registerBeanNameOrInstance(Object mapValue, String beanKey) throws MBeanExportException {
 		try {
-			if (mapValue instanceof String) {
+			if (mapValue instanceof String beanName) {
 				// Bean name pointing to a potentially lazy-init bean in the factory.
 				if (this.beanFactory == null) {
 					throw new MBeanExportException("Cannot resolve bean names if not running in a BeanFactory");
 				}
-				String beanName = (String) mapValue;
 				if (isBeanDefinitionLazyInit(this.beanFactory, beanName)) {
 					ObjectName objectName = registerLazyInit(beanName, beanKey);
 					replaceNotificationListenerBeanNameKeysIfNecessary(beanName, objectName);

spring-context/src/main/java/org/springframework/scripting/bsh/BshScriptUtils.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2022 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.
@@ -90,8 +90,7 @@ public abstract class BshScriptUtils {
 			throws EvalError {
 
 		Object result = evaluateBshScript(scriptSource, scriptInterfaces, classLoader);
-		if (result instanceof Class) {
+		if (result instanceof Class<?> clazz) {
-			Class<?> clazz = (Class<?>) result;
 			try {
 				return ReflectionUtils.accessibleConstructor(clazz).newInstance();
 			}

spring-context/src/main/java/org/springframework/scripting/support/StandardScriptFactory.java

@@ -160,8 +160,7 @@ public class StandardScriptFactory implements ScriptFactory, BeanClassLoaderAwar
 			}
 		}
 
-		if (script instanceof Class) {
+		if (script instanceof Class<?> scriptClass) {
-			Class<?> scriptClass = (Class<?>) script;
 			try {
 				return ReflectionUtils.accessibleConstructor(scriptClass).newInstance();
 			}

spring-context/src/main/java/org/springframework/ui/context/support/ResourceBundleThemeSource.java

@@ -191,8 +191,7 @@ public class ResourceBundleThemeSource implements HierarchicalThemeSource, BeanC
 	 * @param theme the Theme to (re-)initialize
 	 */
 	protected void initParent(Theme theme) {
-		if (theme.getMessageSource() instanceof HierarchicalMessageSource) {
+		if (theme.getMessageSource() instanceof HierarchicalMessageSource messageSource) {
-			HierarchicalMessageSource messageSource = (HierarchicalMessageSource) theme.getMessageSource();
 			if (getParentThemeSource() != null && messageSource.getParentMessageSource() == null) {
 				Theme parentTheme = getParentThemeSource().getTheme(theme.getName());
 				if (parentTheme != null) {

spring-context/src/main/java/org/springframework/validation/DataBinder.java

@@ -852,8 +852,7 @@ public class DataBinder implements PropertyEditorRegistry, TypeConverter {
 					if (pv.getValue() instanceof String) {
 						empty = !StringUtils.hasText((String) pv.getValue());
 					}
-					else if (pv.getValue() instanceof String[]) {
+					else if (pv.getValue() instanceof String[] values) {
-						String[] values = (String[]) pv.getValue();
 						empty = (values.length == 0 || !StringUtils.hasText(values[0]));
 					}
 				}

spring-context/src/test/java/org/springframework/scripting/support/ScriptFactoryPostProcessorTests.java

@@ -49,33 +49,35 @@ class ScriptFactoryPostProcessorTests {
 
 	private static final String PROCESSOR_BEAN_NAME = "processor";
 
-	private static final String CHANGED_SCRIPT = "package org.springframework.scripting.groovy\n" +
+	// quote the returned message (this is the change)...
-			"import org.springframework.scripting.Messenger\n" +
+	private static final String CHANGED_SCRIPT = """
-			"class GroovyMessenger implements Messenger {\n" +
+			package org.springframework.scripting.groovy
-			"  private String message = \"Bingo\"\n" +
+			import org.springframework.scripting.Messenger
-			"  public String getMessage() {\n" +
+			class GroovyMessenger implements Messenger {
-			// quote the returned message (this is the change)...
+				private String message = "Bingo"
-			"    return \"'\"  + this.message + \"'\"\n" +
+				public String getMessage() {
-			"  }\n" +
+					return "'"  + this.message + "'"
-			"  public void setMessage(String message) {\n" +
+				}
-			"    this.message = message\n" +
+				public void setMessage(String message) {
-			"  }\n" +
+					this.message = message
-			"}";
+				}
+			}""";
 
 	private static final String EXPECTED_CHANGED_MESSAGE_TEXT = "'" + MESSAGE_TEXT + "'";
 
 	private static final int DEFAULT_SECONDS_TO_PAUSE = 1;
 
-	private static final String DELEGATING_SCRIPT = "inline:package org.springframework.scripting;\n" +
+	private static final String DELEGATING_SCRIPT = """
-			"class DelegatingMessenger implements Messenger {\n" +
+			inline:package org.springframework.scripting;
-			"  private Messenger wrappedMessenger;\n" +
+			class DelegatingMessenger implements Messenger {
-			"  public String getMessage() {\n" +
+				private Messenger wrappedMessenger;
-			"    return this.wrappedMessenger.getMessage()\n" +
+				public String getMessage() {
-			"  }\n" +
+					return this.wrappedMessenger.getMessage()
-			"  public void setMessenger(Messenger wrappedMessenger) {\n" +
+				}
-			"    this.wrappedMessenger = wrappedMessenger\n" +
+				public void setMessenger(Messenger wrappedMessenger) {
-			"  }\n" +
+					this.wrappedMessenger = wrappedMessenger
-			"}";
+				}
+			}""";
 
 
 	@Test
@@ -245,16 +247,17 @@ class ScriptFactoryPostProcessorTests {
 
 	private static BeanDefinition createScriptedGroovyBean() {
 		BeanDefinitionBuilder builder = BeanDefinitionBuilder.rootBeanDefinition(GroovyScriptFactory.class);
-		builder.addConstructorArgValue("inline:package org.springframework.scripting;\n" +
+		builder.addConstructorArgValue("""
-				"class GroovyMessenger implements Messenger {\n" +
+				inline:package org.springframework.scripting;
-				"  private String message = \"Bingo\"\n" +
+				class GroovyMessenger implements Messenger {
-				"  public String getMessage() {\n" +
+					private String message = "Bingo"
-				"    return this.message\n" +
+					public String getMessage() {
-				"  }\n" +
+						return this.message
-				"  public void setMessage(String message) {\n" +
+					}
-				"    this.message = message\n" +
+					public void setMessage(String message) {
-				"  }\n" +
+						this.message = message
-				"}");
+					}
+				}""");
 		builder.addPropertyValue("message", MESSAGE_TEXT);
 		return builder.getBeanDefinition();
 	}

spring-core/src/jmh/java/org/springframework/core/codec/StringDecoderBenchmark.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2021 the original author or authors.
+ * Copyright 2002-2022 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.
@@ -78,11 +78,14 @@ public class StringDecoderBenchmark {
 
 		@Setup(Level.Trial)
 		public void setup() {
-			String eventTemplate = "id:$1\n" +
+			String eventTemplate = """
-					"event:some-event\n" +
+					id:$1
-					":some-comment-$1-aa\n" +
+					event:some-event
-					":some-comment-$1-bb\n" +
+					:some-comment-$1-aa
-					"data:abcdefg-$1-hijklmnop-$1-qrstuvw-$1-xyz-$1\n\n";
+					:some-comment-$1-bb
+					data:abcdefg-$1-hijklmnop-$1-qrstuvw-$1-xyz-$1
+
+					""";
 
 			int eventLength = String.format(eventTemplate, String.format("%05d", 1)).length();
 			int eventCount = this.totalSize / eventLength;

spring-core/src/main/java/org/springframework/aot/nativex/BasicJsonWriter.java

@@ -152,42 +152,27 @@ class BasicJsonWriter {
 
 	private static String escape(CharSequence input) {
 		StringBuilder builder = new StringBuilder();
-		input.chars().forEach(c -> {
+		input.chars().forEach(c -> builder.append(
-			switch (c) {
+						switch (c) {
-				case '"':
+							case '"' -> "\\\"";
-					builder.append("\\\"");
+							case '\\' -> "\\\\";
-					break;
+							case '/' -> "\\/";
-				case '\\':
+							case '\b' -> "\\b";
-					builder.append("\\\\");
+							case '\f' -> "\\f";
-					break;
+							case '\n' -> "\\n";
-				case '/':
+							case '\r' -> "\\r";
-					builder.append("\\/");
+							case '\t' -> "\\t";
-					break;
+							default -> {
-				case '\b':
+								if (c <= 0x1F) {
-					builder.append("\\b");
+									yield String.format("\\u%04x", c);
-					break;
+								}
-				case '\f':
+								else {
-					builder.append("\\f");
+									yield (char) c;
-					break;
+								}
-				case '\n':
+							}
-					builder.append("\\n");
+						}
-					break;
+				)
-				case '\r':
+		);
-					builder.append("\\r");
-					break;
-				case '\t':
-					builder.append("\\t");
-					break;
-				default:
-					if (c <= 0x1F) {
-						builder.append(String.format("\\u%04x", c));
-					}
-					else {
-						builder.append((char) c);
-					}
-					break;
-			}
-		});
 		return builder.toString();
 	}
 

spring-core/src/main/java/org/springframework/util/MimeTypeUtils.java

@@ -314,18 +314,14 @@ public abstract class MimeTypeUtils {
 		int i = 0;
 		while (i < mimeTypes.length()) {
 			switch (mimeTypes.charAt(i)) {
-				case '"':
+				case '"' -> inQuotes = !inQuotes;
-					inQuotes = !inQuotes;
+				case ',' -> {
-					break;
-				case ',':
 					if (!inQuotes) {
 						tokens.add(mimeTypes.substring(startIndex, i));
 						startIndex = i + 1;
 					}
-					break;
+				}
-				case '\\':
+				case '\\' -> i++;
-					i++;
-					break;
 			}
 			i++;
 		}

spring-core/src/main/java/org/springframework/util/concurrent/FutureAdapter.java

@@ -96,18 +96,18 @@ public abstract class FutureAdapter<T, S> implements Future<T> {
 	@Nullable
 	final T adaptInternal(S adapteeResult) throws ExecutionException {
 		synchronized (this.mutex) {
-			switch (this.state) {
+			return switch (this.state) {
-				case SUCCESS:
+				case SUCCESS -> (T) this.result;
-					return (T) this.result;
+				case FAILURE -> {
-				case FAILURE:
 					Assert.state(this.result instanceof ExecutionException, "Failure without exception");
 					throw (ExecutionException) this.result;
-				case NEW:
+				}
+				case NEW -> {
 					try {
 						T adapted = adapt(adapteeResult);
 						this.result = adapted;
 						this.state = State.SUCCESS;
-						return adapted;
+						yield adapted;
 					}
 					catch (ExecutionException ex) {
 						this.result = ex;
@@ -120,9 +120,8 @@ public abstract class FutureAdapter<T, S> implements Future<T> {
 						this.state = State.FAILURE;
 						throw execEx;
 					}
-				default:
+				}
-					throw new IllegalStateException();
+			};
-			}
 		}
 	}
 

spring-core/src/main/java/org/springframework/util/xml/AbstractStaxXMLReader.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2022 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.
@@ -65,21 +65,19 @@ abstract class AbstractStaxXMLReader extends AbstractXMLReader {
 
 	@Override
 	public boolean getFeature(String name) throws SAXNotRecognizedException, SAXNotSupportedException {
-		switch (name) {
+		return switch (name) {
-			case NAMESPACES_FEATURE_NAME:
+			case NAMESPACES_FEATURE_NAME -> this.namespacesFeature;
-				return this.namespacesFeature;
+			case NAMESPACE_PREFIXES_FEATURE_NAME -> this.namespacePrefixesFeature;
-			case NAMESPACE_PREFIXES_FEATURE_NAME:
+			case IS_STANDALONE_FEATURE_NAME -> {
-				return this.namespacePrefixesFeature;
-			case IS_STANDALONE_FEATURE_NAME:
 				if (this.isStandalone != null) {
-					return this.isStandalone;
+					yield this.isStandalone;
 				}
 				else {
 					throw new SAXNotSupportedException("startDocument() callback not completed yet");
 				}
-			default:
+			}
-				return super.getFeature(name);
+			default -> super.getFeature(name);
-		}
+		};
 	}
 
 	@Override

spring-expression/src/main/java/org/springframework/expression/spel/ast/MethodReference.java

@@ -274,7 +274,7 @@ public class MethodReference extends SpelNodeImpl {
 	public boolean isCompilable() {
 		CachedMethodExecutor executorToCheck = this.cachedExecutor;
 		if (executorToCheck == null || executorToCheck.hasProxyTarget() ||
-				!(executorToCheck.get() instanceof ReflectiveMethodExecutor)) {
+				!(executorToCheck.get() instanceof ReflectiveMethodExecutor executor)) {
 			return false;
 		}
 
@@ -284,26 +284,20 @@ public class MethodReference extends SpelNodeImpl {
 			}
 		}
 
-		ReflectiveMethodExecutor executor = (ReflectiveMethodExecutor) executorToCheck.get();
 		if (executor.didArgumentConversionOccur()) {
 			return false;
 		}
 		Class<?> clazz = executor.getMethod().getDeclaringClass();
-		if (!Modifier.isPublic(clazz.getModifiers()) && executor.getPublicDeclaringClass() == null) {
+		return Modifier.isPublic(clazz.getModifiers()) || executor.getPublicDeclaringClass() != null;
-			return false;
-		}
-
-		return true;
 	}
 
 	@Override
 	public void generateCode(MethodVisitor mv, CodeFlow cf) {
 		CachedMethodExecutor executorToCheck = this.cachedExecutor;
-		if (executorToCheck == null || !(executorToCheck.get() instanceof ReflectiveMethodExecutor)) {
+		if (executorToCheck == null || !(executorToCheck.get() instanceof ReflectiveMethodExecutor methodExecutor)) {
 			throw new IllegalStateException("No applicable cached executor found: " + executorToCheck);
 		}
 
-		ReflectiveMethodExecutor methodExecutor = (ReflectiveMethodExecutor) executorToCheck.get();
 		Method method = methodExecutor.getMethod();
 		boolean isStaticMethod = Modifier.isStatic(method.getModifiers());
 		String descriptor = cf.lastDescriptor();

spring-jms/src/main/java/org/springframework/jms/connection/CachingConnectionFactory.java

@@ -365,45 +365,54 @@ public class CachingConnectionFactory extends SingleConnectionFactory {
 				}
 				else if (isCacheConsumers()) {
 					// let raw JMS invocation throw an exception if Destination (i.e. args[0]) is null
-					if ((methodName.equals("createConsumer") || methodName.equals("createReceiver") ||
+					switch (methodName) {
-							methodName.equals("createSubscriber"))) {
+						case "createConsumer", "createReceiver", "createSubscriber" -> {
-						Destination dest = (Destination) args[0];
+							Destination dest = (Destination) args[0];
-						if (dest != null && !(dest instanceof TemporaryQueue || dest instanceof TemporaryTopic)) {
+							if (dest != null && !(dest instanceof TemporaryQueue || dest instanceof TemporaryTopic)) {
-							return getCachedConsumer(dest,
+								return getCachedConsumer(
-									(args.length > 1 ? (String) args[1] : null),
+										dest,
-									(args.length > 2 && (Boolean) args[2]),
+										(args.length > 1 ? (String) args[1] : null),
-									null,
+										(args.length > 2 && (Boolean) args[2]),
-									false);
+										null,
+										false
+								);
+							}
 						}
-					}
+						case "createDurableConsumer", "createDurableSubscriber" -> {
-					else if (methodName.equals("createDurableConsumer") || methodName.equals("createDurableSubscriber")) {
+							Destination dest = (Destination) args[0];
-						Destination dest = (Destination) args[0];
+							if (dest != null) {
-						if (dest != null) {
+								return getCachedConsumer(
-							return getCachedConsumer(dest,
+										dest,
-									(args.length > 2 ? (String) args[2] : null),
+										(args.length > 2 ? (String) args[2] : null),
-									(args.length > 3 && (Boolean) args[3]),
+										(args.length > 3 && (Boolean) args[3]),
-									(String) args[1],
+										(String) args[1],
-									true);
+										true
+								);
+							}
 						}
-					}
+						case "createSharedConsumer" -> {
-					else if (methodName.equals("createSharedConsumer")) {
+							Destination dest = (Destination) args[0];
-						Destination dest = (Destination) args[0];
+							if (dest != null) {
-						if (dest != null) {
+								return getCachedConsumer(
-							return getCachedConsumer(dest,
+										dest,
-									(args.length > 2 ? (String) args[2] : null),
+										(args.length > 2 ? (String) args[2] : null),
-									null,
+										null,
-									(String) args[1],
+										(String) args[1],
-									false);
+										false
+								);
+							}
 						}
-					}
+						case "createSharedDurableConsumer" -> {
-					else if (methodName.equals("createSharedDurableConsumer")) {
+							Destination dest = (Destination) args[0];
-						Destination dest = (Destination) args[0];
+							if (dest != null) {
-						if (dest != null) {
+								return getCachedConsumer(
-							return getCachedConsumer(dest,
+										dest,
-									(args.length > 2 ? (String) args[2] : null),
+										(args.length > 2 ? (String) args[2] : null),
-									null,
+										null,
-									(String) args[1],
+										(String) args[1],
-									true);
+										true
+								);
+							}
 						}
 					}
 				}

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

@@ -378,10 +378,9 @@ public abstract class AbstractMethodMessageHandler<T>
 	 */
 	protected HandlerMethod createHandlerMethod(Object handler, Method method) {
 		HandlerMethod handlerMethod;
-		if (handler instanceof String) {
+		if (handler instanceof String beanName) {
 			ApplicationContext context = getApplicationContext();
 			Assert.state(context != null, "ApplicationContext is required for resolving handler bean names");
-			String beanName = (String) handler;
 			handlerMethod = new HandlerMethod(beanName, context.getAutowireCapableBeanFactory(), method);
 		}
 		else {

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

@@ -93,10 +93,9 @@ public class GenericMessage<T> implements Message<T>, Serializable {
 		if (this == other) {
 			return true;
 		}
-		if (!(other instanceof GenericMessage)) {
+		if (!(other instanceof GenericMessage<?> otherMsg)) {
 			return false;
 		}
-		GenericMessage<?> otherMsg = (GenericMessage<?>) other;
 		// Using nullSafeEquals for proper array equals comparisons
 		return (ObjectUtils.nullSafeEquals(this.payload, otherMsg.payload) && this.headers.equals(otherMsg.headers));
 	}

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

@@ -617,8 +617,7 @@ public class MessageHeaderAccessor {
 	 * @since 4.1
 	 */
 	public static MessageHeaderAccessor getMutableAccessor(Message<?> message) {
-		if (message.getHeaders() instanceof MutableMessageHeaders) {
+		if (message.getHeaders() instanceof MutableMessageHeaders mutableHeaders) {
-			MutableMessageHeaders mutableHeaders = (MutableMessageHeaders) message.getHeaders();
 			MessageHeaderAccessor accessor = mutableHeaders.getAccessor();
 			return (accessor.isMutable() ? accessor : accessor.createAccessor(message));
 		}

spring-messaging/src/test/java/org/springframework/messaging/converter/ProtobufMessageConverterTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2022 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.
@@ -62,13 +62,13 @@ public class ProtobufMessageConverterTests {
 		this.message = MessageBuilder.withPayload(this.testMsg.toByteArray())
 				.setHeader(CONTENT_TYPE, ProtobufMessageConverter.PROTOBUF).build();
 		this.messageWithoutContentType = MessageBuilder.withPayload(this.testMsg.toByteArray()).build();
-		this.messageJson = MessageBuilder.withPayload(
+		this.messageJson = MessageBuilder.withPayload("""
-					"{\n" +
+					{
-					"  \"foo\": \"Foo\",\n" +
+						"foo": "Foo",
-					"  \"blah\": {\n" +
+						"blah": {
-					"    \"blah\": 123\n" +
+							"blah": 123
-					"  }\n" +
+						}
-						"}")
+					}""".replace("\t", "  "))
 				.setHeader(CONTENT_TYPE, APPLICATION_JSON)
 				.build();
 	}

spring-messaging/src/test/java/org/springframework/messaging/support/MessageHeaderAccessorTests.java

@@ -319,9 +319,7 @@ public class MessageHeaderAccessorTests {
 		})).isEqualTo(expected);
 
 		StringBuilder sb = new StringBuilder();
-		for (int i = 0; i < 80; i++) {
+		sb.append("a".repeat(80));
-			sb.append('a');
-		}
 		final String payload = sb.toString() + " > 80";
 
 		String actual = accessor.getShortLogMessage(payload);
@@ -355,10 +353,8 @@ public class MessageHeaderAccessorTests {
 		})).isEqualTo(expected);
 
 		StringBuilder sb = new StringBuilder();
-		for (int i = 0; i < 80; i++) {
+		sb.append("a".repeat(80));
-			sb.append('a');
+		final String payload = sb + " > 80";
-		}
-		final String payload = sb.toString() + " > 80";
 
 		String actual = accessor.getDetailedLogMessage(payload);
 		assertThat(actual).isEqualTo("headers={contentType=text/plain} payload=" + sb + " > 80");

spring-orm/src/main/java/org/springframework/orm/hibernate5/HibernateTransactionManager.java

@@ -362,11 +362,10 @@ public class HibernateTransactionManager extends AbstractPlatformTransactionMana
 		if (this.entityInterceptor instanceof Interceptor) {
 			return (Interceptor) this.entityInterceptor;
 		}
-		else if (this.entityInterceptor instanceof String) {
+		else if (this.entityInterceptor instanceof String beanName) {
 			if (this.beanFactory == null) {
 				throw new IllegalStateException("Cannot get entity interceptor via bean name if no bean factory set");
 			}
-			String beanName = (String) this.entityInterceptor;
 			return this.beanFactory.getBean(beanName, Interceptor.class);
 		}
 		else {

spring-orm/src/main/java/org/springframework/orm/jpa/JpaTransactionManager.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2021 the original author or authors.
+ * Copyright 2002-2022 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.
@@ -344,8 +344,7 @@ public class JpaTransactionManager extends AbstractPlatformTransactionManager
 		if (getEntityManagerFactory() == null) {
 			throw new IllegalArgumentException("'entityManagerFactory' or 'persistenceUnitName' is required");
 		}
-		if (getEntityManagerFactory() instanceof EntityManagerFactoryInfo) {
+		if (getEntityManagerFactory() instanceof EntityManagerFactoryInfo emfInfo) {
-			EntityManagerFactoryInfo emfInfo = (EntityManagerFactoryInfo) getEntityManagerFactory();
 			DataSource dataSource = emfInfo.getDataSource();
 			if (dataSource != null) {
 				setDataSource(dataSource);

spring-test/src/test/java/org/springframework/test/context/jdbc/InfrastructureProxyTransactionalSqlScriptsTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2021 the original author or authors.
+ * Copyright 2002-2022 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.
@@ -107,21 +107,19 @@ class InfrastructureProxyTransactionalSqlScriptsTests extends AbstractTransactio
 
 		@Override
 		public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
-			switch (method.getName()) {
+			return switch (method.getName()) {
-				case "equals":
+				case "equals" -> (proxy == args[0]);
-					return (proxy == args[0]);
+				case "hashCode" -> System.identityHashCode(proxy);
-				case "hashCode":
+				case "getWrappedObject" -> this.dataSource;
-					return System.identityHashCode(proxy);
+				default -> {
-				case "getWrappedObject":
-					return this.dataSource;
-				default:
 					try {
-						return method.invoke(this.dataSource, args);
+						yield method.invoke(this.dataSource, args);
 					}
 					catch (InvocationTargetException ex) {
 						throw ex.getTargetException();
 					}
-			}
+				}
+			};
 		}
 	}
 

spring-tx/src/main/java/org/springframework/transaction/annotation/TransactionManagementConfigurationSelector.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2022 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.
@@ -45,15 +45,13 @@ public class TransactionManagementConfigurationSelector extends AdviceModeImport
 	 */
 	@Override
 	protected String[] selectImports(AdviceMode adviceMode) {
-		switch (adviceMode) {
+		return switch (adviceMode) {
-			case PROXY:
+			case PROXY -> new String[]{
-				return new String[] {AutoProxyRegistrar.class.getName(),
+					AutoProxyRegistrar.class.getName(),
-						ProxyTransactionManagementConfiguration.class.getName()};
+					ProxyTransactionManagementConfiguration.class.getName()
-			case ASPECTJ:
+			};
-				return new String[] {determineTransactionAspectClass()};
+			case ASPECTJ -> new String[]{determineTransactionAspectClass()};
-			default:
+		};
-				return null;
-		}
 	}
 
 	private String determineTransactionAspectClass() {

spring-tx/src/test/java/org/springframework/transaction/interceptor/TransactionAttributeSourceEditorTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2022 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.
@@ -56,12 +56,12 @@ public class TransactionAttributeSourceEditorTests {
 
 	@Test
 	public void matchesSpecific() throws Exception {
-		editor.setAsText(
+		editor.setAsText("""
-			"java.lang.Object.hashCode=PROPAGATION_REQUIRED\n" +
+				java.lang.Object.hashCode=PROPAGATION_REQUIRED
-			"java.lang.Object.equals=PROPAGATION_MANDATORY\n" +
+				java.lang.Object.equals=PROPAGATION_MANDATORY
-			"java.lang.Object.*it=PROPAGATION_SUPPORTS\n" +
+				java.lang.Object.*it=PROPAGATION_SUPPORTS
-			"java.lang.Object.notify=PROPAGATION_SUPPORTS\n" +
+				java.lang.Object.notify=PROPAGATION_SUPPORTS
-			"java.lang.Object.not*=PROPAGATION_REQUIRED");
+				java.lang.Object.not*=PROPAGATION_REQUIRED""");
 		TransactionAttributeSource tas = (TransactionAttributeSource) editor.getValue();
 
 		checkTransactionProperties(tas, Object.class.getMethod("hashCode"),

spring-web/src/main/java/org/springframework/web/client/HttpServerErrorException.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2022 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.
@@ -97,32 +97,26 @@ public class HttpServerErrorException extends HttpStatusCodeException {
 			String statusText, HttpHeaders headers, byte[] body, @Nullable Charset charset) {
 
 		if (statusCode instanceof HttpStatus status) {
-			switch (status) {
+			return switch (status) {
-				case INTERNAL_SERVER_ERROR:
+				case INTERNAL_SERVER_ERROR -> message != null ?
-					return message != null ?
+						new InternalServerError(message, statusText, headers, body, charset) :
-						new HttpServerErrorException.InternalServerError(message, statusText, headers, body, charset) :
+						new InternalServerError(statusText, headers, body, charset);
-							new HttpServerErrorException.InternalServerError(statusText, headers, body, charset);
+				case NOT_IMPLEMENTED -> message != null ?
-				case NOT_IMPLEMENTED:
+						new NotImplemented(message, statusText, headers, body, charset) :
-					return message != null ?
+						new NotImplemented(statusText, headers, body, charset);
-							new HttpServerErrorException.NotImplemented(message, statusText, headers, body, charset) :
+				case BAD_GATEWAY -> message != null ?
-							new HttpServerErrorException.NotImplemented(statusText, headers, body, charset);
+						new BadGateway(message, statusText, headers, body, charset) :
-				case BAD_GATEWAY:
+						new BadGateway(statusText, headers, body, charset);
-					return message != null ?
+				case SERVICE_UNAVAILABLE -> message != null ?
-							new HttpServerErrorException.BadGateway(message, statusText, headers, body, charset) :
+						new ServiceUnavailable(message, statusText, headers, body, charset) :
-							new HttpServerErrorException.BadGateway(statusText, headers, body, charset);
+						new ServiceUnavailable(statusText, headers, body, charset);
-				case SERVICE_UNAVAILABLE:
+				case GATEWAY_TIMEOUT -> message != null ?
-					return message != null ?
+						new GatewayTimeout(message, statusText, headers, body, charset) :
-						new HttpServerErrorException.ServiceUnavailable(message, statusText, headers, body, charset) :
+						new GatewayTimeout(statusText, headers, body, charset);
-							new HttpServerErrorException.ServiceUnavailable(statusText, headers, body, charset);
+				default -> message != null ?
-				case GATEWAY_TIMEOUT:
+						new HttpServerErrorException(message, statusCode, statusText, headers, body, charset) :
-					return message != null ?
+						new HttpServerErrorException(statusCode, statusText, headers, body, charset);
-							new HttpServerErrorException.GatewayTimeout(message, statusText, headers, body, charset) :
+			};
-							new HttpServerErrorException.GatewayTimeout(statusText, headers, body, charset);
-				default:
-					return message != null ?
-							new HttpServerErrorException(message, statusCode, statusText, headers, body, charset) :
-							new HttpServerErrorException(statusCode, statusText, headers, body, charset);
-			}
 		}
 		if (message != null) {
 			return new HttpServerErrorException(message, statusCode, statusText, headers, body, charset);

spring-web/src/main/java/org/springframework/web/cors/CorsConfiguration.java

@@ -263,18 +263,14 @@ public class CorsConfiguration {
 		boolean withinPortRange = false;
 		for (int current = 0; current < rawValue.length(); current++) {
 			switch (rawValue.charAt(current)) {
-				case '[':
+				case '[' -> withinPortRange = true;
-					withinPortRange = true;
+				case ']' -> withinPortRange = false;
-					break;
+				case ',' -> {
-				case ']':
-					withinPortRange = false;
-					break;
-				case ',':
 					if (!withinPortRange) {
 						valueConsumer.accept(rawValue.substring(start, current).trim());
 						start = current + 1;
 					}
-					break;
+				}
 			}
 		}
 		if (start < rawValue.length()) {

spring-web/src/test/java/org/springframework/http/codec/ServerSentEventHttpMessageReaderTests.java

@@ -159,8 +159,12 @@ public class ServerSentEventHttpMessageReaderTests extends AbstractLeakCheckingT
 	public void readPojo() {
 		MockServerHttpRequest request = MockServerHttpRequest.post("/")
 				.body(Mono.just(stringBuffer(
-						"data:{\"foo\": \"foofoo\", \"bar\": \"barbar\"}\n\n" +
+						"""
-								"data:{\"foo\": \"foofoofoo\", \"bar\": \"barbarbar\"}\n\n")));
+								data:{"foo": "foofoo", "bar": "barbar"}
+
+								data:{"foo": "foofoofoo", "bar": "barbarbar"}
+
+								""")));
 
 		Flux<Pojo> data = reader.read(ResolvableType.forClass(Pojo.class), request,
 				Collections.emptyMap()).cast(Pojo.class);

spring-web/src/test/java/org/springframework/http/codec/ServerSentEventHttpMessageWriterTests.java

@@ -173,14 +173,18 @@ class ServerSentEventHttpMessageWriterTests extends AbstractDataBufferAllocating
 
 		StepVerifier.create(outputMessage.getBody())
 				.consumeNextWith(stringConsumer("data:"))
-				.consumeNextWith(stringConsumer("{\n" +
+				.consumeNextWith(stringConsumer("""
-						"data:  \"foo\" : \"foofoo\",\n" +
+						{
-						"data:  \"bar\" : \"barbar\"\n" + "data:}"))
+						data:  "foo" : "foofoo",
+						data:  "bar" : "barbar"
+						data:}"""))
 				.consumeNextWith(stringConsumer("\n\n"))
 				.consumeNextWith(stringConsumer("data:"))
-				.consumeNextWith(stringConsumer("{\n" +
+				.consumeNextWith(stringConsumer("""
-						"data:  \"foo\" : \"foofoofoo\",\n" +
+						{
-						"data:  \"bar\" : \"barbarbar\"\n" + "data:}"))
+						data:  "foo" : "foofoofoo",
+						data:  "bar" : "barbarbar"
+						data:}"""))
 				.consumeNextWith(stringConsumer("\n\n"))
 				.expectComplete()
 				.verify();

spring-web/src/test/java/org/springframework/http/converter/xml/Jaxb2CollectionHttpMessageConverterTests.java

@@ -181,21 +181,22 @@ public class Jaxb2CollectionHttpMessageConverterTests {
 	public void testXmlBomb() throws Exception {
 		// https://en.wikipedia.org/wiki/Billion_laughs
 		// https://msdn.microsoft.com/en-us/magazine/ee335713.aspx
-		String content = "<?xml version=\"1.0\"?>\n" +
+		String content = """
-				"<!DOCTYPE lolz [\n" +
+				<?xml version="1.0"?>
-				" <!ENTITY lol \"lol\">\n" +
+				<!DOCTYPE lolz [
-				" <!ELEMENT lolz (#PCDATA)>\n" +
+					<!ENTITY lol "lol">
-				" <!ENTITY lol1 \"&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;\">\n" +
+					<!ELEMENT lolz (#PCDATA)>
-				" <!ENTITY lol2 \"&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;\">\n" +
+					<!ENTITY lol1 "&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;">
-				" <!ENTITY lol3 \"&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;\">\n" +
+					<!ENTITY lol2 "&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;">
-				" <!ENTITY lol4 \"&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;\">\n" +
+					<!ENTITY lol3 "&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;">
-				" <!ENTITY lol5 \"&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;\">\n" +
+					<!ENTITY lol4 "&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;">
-				" <!ENTITY lol6 \"&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;\">\n" +
+					<!ENTITY lol5 "&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;">
-				" <!ENTITY lol7 \"&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;\">\n" +
+					<!ENTITY lol6 "&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;">
-				" <!ENTITY lol8 \"&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;\">\n" +
+					<!ENTITY lol7 "&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;">
-				" <!ENTITY lol9 \"&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;\">\n" +
+					<!ENTITY lol8 "&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;">
-				"]>\n" +
+					<!ENTITY lol9 "&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;">
-				"<list><rootElement><external>&lol9;</external></rootElement></list>";
+				]>
+				<list><rootElement><external>&lol9;</external></rootElement></list>""";
 		MockHttpInputMessage inputMessage = new MockHttpInputMessage(content.getBytes(StandardCharsets.UTF_8));
 		assertThatExceptionOfType(HttpMessageNotReadableException.class)
 				.isThrownBy(() -> this.converter.read(this.rootElementListType, null, inputMessage))

spring-web/src/test/java/org/springframework/http/converter/xml/Jaxb2RootElementHttpMessageConverterTests.java

@@ -153,21 +153,22 @@ public class Jaxb2RootElementHttpMessageConverterTests {
 	public void testXmlBomb() throws Exception {
 		// https://en.wikipedia.org/wiki/Billion_laughs
 		// https://msdn.microsoft.com/en-us/magazine/ee335713.aspx
-		String content = "<?xml version=\"1.0\"?>\n" +
+		String content = """
-				"<!DOCTYPE lolz [\n" +
+				<?xml version="1.0"?>
-				" <!ENTITY lol \"lol\">\n" +
+				<!DOCTYPE lolz [
-				" <!ELEMENT lolz (#PCDATA)>\n" +
+					<!ENTITY lol "lol">
-				" <!ENTITY lol1 \"&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;\">\n" +
+					<!ELEMENT lolz (#PCDATA)>
-				" <!ENTITY lol2 \"&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;\">\n" +
+					<!ENTITY lol1 "&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;">
-				" <!ENTITY lol3 \"&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;\">\n" +
+					<!ENTITY lol2 "&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;">
-				" <!ENTITY lol4 \"&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;\">\n" +
+					<!ENTITY lol3 "&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;">
-				" <!ENTITY lol5 \"&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;\">\n" +
+					<!ENTITY lol4 "&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;">
-				" <!ENTITY lol6 \"&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;\">\n" +
+					<!ENTITY lol5 "&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;">
-				" <!ENTITY lol7 \"&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;\">\n" +
+					<!ENTITY lol6 "&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;">
-				" <!ENTITY lol8 \"&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;\">\n" +
+					<!ENTITY lol7 "&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;">
-				" <!ENTITY lol9 \"&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;\">\n" +
+					<!ENTITY lol8 "&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;">
-				"]>\n" +
+					<!ENTITY lol9 "&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;">
-				"<rootElement><external>&lol9;</external></rootElement>";
+				]>
+				<rootElement><external>&lol9;</external></rootElement>""";
 		MockHttpInputMessage inputMessage = new MockHttpInputMessage(content.getBytes(StandardCharsets.UTF_8));
 		assertThatExceptionOfType(HttpMessageNotReadableException.class).isThrownBy(() ->
 				this.converter.read(RootElement.class, inputMessage))

spring-web/src/test/java/org/springframework/http/converter/xml/MappingJackson2XmlHttpMessageConverterTests.java

@@ -168,21 +168,22 @@ public class MappingJackson2XmlHttpMessageConverterTests {
 	public void readWithXmlBomb() throws IOException {
 		// https://en.wikipedia.org/wiki/Billion_laughs
 		// https://msdn.microsoft.com/en-us/magazine/ee335713.aspx
-		String body = "<?xml version=\"1.0\"?>\n" +
+		String body = """
-				"<!DOCTYPE lolz [\n" +
+				<?xml version="1.0"?>
-				" <!ENTITY lol \"lol\">\n" +
+				<!DOCTYPE lolz [
-				" <!ELEMENT lolz (#PCDATA)>\n" +
+					<!ENTITY lol "lol">
-				" <!ENTITY lol1 \"&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;\">\n" +
+					<!ELEMENT lolz (#PCDATA)>
-				" <!ENTITY lol2 \"&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;\">\n" +
+					<!ENTITY lol1 "&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;">
-				" <!ENTITY lol3 \"&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;\">\n" +
+					<!ENTITY lol2 "&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;">
-				" <!ENTITY lol4 \"&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;\">\n" +
+					<!ENTITY lol3 "&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;">
-				" <!ENTITY lol5 \"&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;\">\n" +
+					<!ENTITY lol4 "&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;">
-				" <!ENTITY lol6 \"&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;\">\n" +
+					<!ENTITY lol5 "&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;">
-				" <!ENTITY lol7 \"&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;\">\n" +
+					<!ENTITY lol6 "&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;">
-				" <!ENTITY lol8 \"&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;\">\n" +
+					<!ENTITY lol7 "&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;">
-				" <!ENTITY lol9 \"&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;\">\n" +
+					<!ENTITY lol8 "&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;">
-				"]>\n" +
+					<!ENTITY lol9 "&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;">
-				"<MyBean>&lol9;</MyBean>";
+				]>
+				<MyBean>&lol9;</MyBean>""";
 
 		MockHttpInputMessage inputMessage = new MockHttpInputMessage(body.getBytes(StandardCharsets.UTF_8));
 		inputMessage.getHeaders().setContentType(MediaType.APPLICATION_XML);

spring-web/src/test/java/org/springframework/http/converter/xml/SourceHttpMessageConverterTests.java

@@ -112,21 +112,22 @@ public class SourceHttpMessageConverterTests {
 	public void readDomSourceWithXmlBomb() throws Exception {
 		// https://en.wikipedia.org/wiki/Billion_laughs
 		// https://msdn.microsoft.com/en-us/magazine/ee335713.aspx
-		String content = "<?xml version=\"1.0\"?>\n" +
+		String content = """
-				"<!DOCTYPE lolz [\n" +
+				<?xml version="1.0"?>
-				" <!ENTITY lol \"lol\">\n" +
+				<!DOCTYPE lolz [
-				" <!ELEMENT lolz (#PCDATA)>\n" +
+					<!ENTITY lol "lol">
-				" <!ENTITY lol1 \"&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;\">\n" +
+					<!ELEMENT lolz (#PCDATA)>
-				" <!ENTITY lol2 \"&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;\">\n" +
+					<!ENTITY lol1 "&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;">
-				" <!ENTITY lol3 \"&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;\">\n" +
+					<!ENTITY lol2 "&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;">
-				" <!ENTITY lol4 \"&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;\">\n" +
+					<!ENTITY lol3 "&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;">
-				" <!ENTITY lol5 \"&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;\">\n" +
+					<!ENTITY lol4 "&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;">
-				" <!ENTITY lol6 \"&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;\">\n" +
+					<!ENTITY lol5 "&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;">
-				" <!ENTITY lol7 \"&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;\">\n" +
+					<!ENTITY lol6 "&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;">
-				" <!ENTITY lol8 \"&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;\">\n" +
+					<!ENTITY lol7 "&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;">
-				" <!ENTITY lol9 \"&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;\">\n" +
+					<!ENTITY lol8 "&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;">
-				"]>\n" +
+					<!ENTITY lol9 "&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;">
-				"<root>&lol9;</root>";
+				]>
+				<root>&lol9;</root>""";
 		MockHttpInputMessage inputMessage = new MockHttpInputMessage(content.getBytes(StandardCharsets.UTF_8));
 
 		assertThatExceptionOfType(HttpMessageNotReadableException.class).isThrownBy(() ->
@@ -166,21 +167,22 @@ public class SourceHttpMessageConverterTests {
 	public void readSAXSourceWithXmlBomb() throws Exception {
 		// https://en.wikipedia.org/wiki/Billion_laughs
 		// https://msdn.microsoft.com/en-us/magazine/ee335713.aspx
-		String content = "<?xml version=\"1.0\"?>\n" +
+		String content = """
-				"<!DOCTYPE lolz [\n" +
+				<?xml version="1.0"?>
-				" <!ENTITY lol \"lol\">\n" +
+				<!DOCTYPE lolz [
-				" <!ELEMENT lolz (#PCDATA)>\n" +
+					<!ENTITY lol "lol">
-				" <!ENTITY lol1 \"&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;\">\n" +
+					<!ELEMENT lolz (#PCDATA)>
-				" <!ENTITY lol2 \"&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;\">\n" +
+					<!ENTITY lol1 "&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;">
-				" <!ENTITY lol3 \"&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;\">\n" +
+					<!ENTITY lol2 "&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;">
-				" <!ENTITY lol4 \"&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;\">\n" +
+					<!ENTITY lol3 "&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;">
-				" <!ENTITY lol5 \"&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;\">\n" +
+					<!ENTITY lol4 "&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;">
-				" <!ENTITY lol6 \"&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;\">\n" +
+					<!ENTITY lol5 "&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;">
-				" <!ENTITY lol7 \"&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;\">\n" +
+					<!ENTITY lol6 "&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;">
-				" <!ENTITY lol8 \"&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;\">\n" +
+					<!ENTITY lol7 "&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;">
-				" <!ENTITY lol9 \"&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;\">\n" +
+					<!ENTITY lol8 "&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;">
-				"]>\n" +
+					<!ENTITY lol9 "&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;">
-				"<root>&lol9;</root>";
+				]>
+				<root>&lol9;</root>""";
 
 		MockHttpInputMessage inputMessage = new MockHttpInputMessage(content.getBytes(StandardCharsets.UTF_8));
 		SAXSource result = (SAXSource) this.converter.read(SAXSource.class, inputMessage);
@@ -232,21 +234,22 @@ public class SourceHttpMessageConverterTests {
 	public void readStAXSourceWithXmlBomb() throws Exception {
 		// https://en.wikipedia.org/wiki/Billion_laughs
 		// https://msdn.microsoft.com/en-us/magazine/ee335713.aspx
-		String content = "<?xml version=\"1.0\"?>\n" +
+		String content = """
-				"<!DOCTYPE lolz [\n" +
+				<?xml version="1.0"?>
-				" <!ENTITY lol \"lol\">\n" +
+				<!DOCTYPE lolz [
-				" <!ELEMENT lolz (#PCDATA)>\n" +
+					<!ENTITY lol "lol">
-				" <!ENTITY lol1 \"&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;\">\n" +
+					<!ELEMENT lolz (#PCDATA)>
-				" <!ENTITY lol2 \"&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;\">\n" +
+					<!ENTITY lol1 "&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;">
-				" <!ENTITY lol3 \"&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;\">\n" +
+					<!ENTITY lol2 "&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;">
-				" <!ENTITY lol4 \"&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;\">\n" +
+					<!ENTITY lol3 "&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;">
-				" <!ENTITY lol5 \"&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;\">\n" +
+					<!ENTITY lol4 "&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;">
-				" <!ENTITY lol6 \"&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;\">\n" +
+					<!ENTITY lol5 "&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;">
-				" <!ENTITY lol7 \"&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;\">\n" +
+					<!ENTITY lol6 "&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;">
-				" <!ENTITY lol8 \"&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;\">\n" +
+					<!ENTITY lol7 "&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;">
-				" <!ENTITY lol9 \"&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;\">\n" +
+					<!ENTITY lol8 "&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;">
-				"]>\n" +
+					<!ENTITY lol9 "&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;">
-				"<root>&lol9;</root>";
+				]>
+				<root>&lol9;</root>""";
 		MockHttpInputMessage inputMessage = new MockHttpInputMessage(content.getBytes(StandardCharsets.UTF_8));
 		StAXSource result = (StAXSource) this.converter.read(StAXSource.class, inputMessage);
 

spring-web/src/test/java/org/springframework/web/multipart/support/StandardMultipartHttpServletRequestTests.java

@@ -84,11 +84,13 @@ public class StandardMultipartHttpServletRequestTests {
 		new FormHttpMessageConverter().write(map, null, output);
 
 		assertThat(output.getBodyAsString(StandardCharsets.UTF_8)).contains(
-				"Content-Disposition: form-data; name=\"file\"; filename=\"myFile.txt\"\r\n" +
+				"""
-						"Content-Type: text/plain\r\n" +
+						Content-Disposition: form-data; name="file"; filename="myFile.txt"\r
-						"Content-Length: 6\r\n" +
+						Content-Type: text/plain\r
-						"\r\n" +
+						Content-Length: 6\r
-						"myBody\r\n");
+						\r
+						myBody\r
+						""");
 	}
 
 

spring-webflux/src/main/java/org/springframework/web/reactive/socket/CloseStatus.java

@@ -201,34 +201,22 @@ public final class CloseStatus {
 	 */
 	public static CloseStatus create(int code, @Nullable String reason) {
 		if (!StringUtils.hasText(reason)) {
-			switch (code) {
+			return switch (code) {
-				case 1000:
+				case 1000 -> NORMAL;
-					return NORMAL;
+				case 1001 -> GOING_AWAY;
-				case 1001:
+				case 1002 -> PROTOCOL_ERROR;
-					return GOING_AWAY;
+				case 1003 -> NOT_ACCEPTABLE;
-				case 1002:
+				case 1005 -> NO_STATUS_CODE;
-					return PROTOCOL_ERROR;
+				case 1006 -> NO_CLOSE_FRAME;
-				case 1003:
+				case 1007 -> BAD_DATA;
-					return NOT_ACCEPTABLE;
+				case 1008 -> POLICY_VIOLATION;
-				case 1005:
+				case 1009 -> TOO_BIG_TO_PROCESS;
-					return NO_STATUS_CODE;
+				case 1010 -> REQUIRED_EXTENSION;
-				case 1006:
+				case 1011 -> SERVER_ERROR;
-					return NO_CLOSE_FRAME;
+				case 1012 -> SERVICE_RESTARTED;
-				case 1007:
+				case 1013 -> SERVICE_OVERLOAD;
-					return BAD_DATA;
+				default -> new CloseStatus(code, reason);
-				case 1008:
+			};
-					return POLICY_VIOLATION;
-				case 1009:
-					return TOO_BIG_TO_PROCESS;
-				case 1010:
-					return REQUIRED_EXTENSION;
-				case 1011:
-					return SERVER_ERROR;
-				case 1012:
-					return SERVICE_RESTARTED;
-				case 1013:
-					return SERVICE_OVERLOAD;
-			}
 		}
 		return new CloseStatus(code, reason);
 	}

spring-webflux/src/test/java/org/springframework/web/reactive/FlushingIntegrationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2021 the original author or authors.
+ * Copyright 2002-2022 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.
@@ -125,26 +125,20 @@ class FlushingIntegrationTests extends AbstractHttpHandlerIntegrationTests {
 		@Override
 		public Mono<Void> handle(ServerHttpRequest request, ServerHttpResponse response) {
 			String path = request.getURI().getPath();
-			switch (path) {
+			return switch (path) {
-				case "/write-and-flush":
+				case "/write-and-flush" -> response.writeAndFlushWith(
-					return response.writeAndFlushWith(
+						testInterval(Duration.ofMillis(50), 2)
-							testInterval(Duration.ofMillis(50), 2)
+								.map(longValue -> wrap("data" + longValue + "\n", response))
-									.map(longValue -> wrap("data" + longValue + "\n", response))
+								.map(Flux::just)
-									.map(Flux::just)
+								.mergeWith(Flux.never()));
-									.mergeWith(Flux.never()));
+				case "/write-and-complete" -> response.writeWith(
-
+						chunks1K().take(64).map(s -> wrap(s, response)));
-				case "/write-and-complete":
+				case "/write-and-never-complete" ->
-					return response.writeWith(
-							chunks1K().take(64).map(s -> wrap(s, response)));
-
-				case "/write-and-never-complete":
 					// Reactor requires at least 50 to flush, Tomcat/Undertow 8, Jetty 1
-					return response.writeWith(
+						response.writeWith(
-							chunks1K().take(64).map(s -> wrap(s, response)).mergeWith(Flux.never()));
+								chunks1K().take(64).map(s -> wrap(s, response)).mergeWith(Flux.never()));
-
+				default -> response.writeWith(Flux.empty());
-				default:
+			};
-					return response.writeWith(Flux.empty());
-			}
 		}
 
 		private Flux<String> chunks1K() {

spring-webflux/src/test/java/org/springframework/web/reactive/function/BodyExtractorsTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2021 the original author or authors.
+ * Copyright 2002-2022 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.
@@ -336,23 +336,25 @@ public class BodyExtractorsTests {
 	public void toParts() {
 		BodyExtractor<Flux<Part>, ServerHttpRequest> extractor = BodyExtractors.toParts();
 
-		String bodyContents = "-----------------------------9051914041544843365972754266\r\n" +
+		String bodyContents = """
-				"Content-Disposition: form-data; name=\"text\"\r\n" +
+				-----------------------------9051914041544843365972754266\r
-				"\r\n" +
+				Content-Disposition: form-data; name="text"\r
-				"text default\r\n" +
+				\r
-				"-----------------------------9051914041544843365972754266\r\n" +
+				text default\r
-				"Content-Disposition: form-data; name=\"file1\"; filename=\"a.txt\"\r\n" +
+				-----------------------------9051914041544843365972754266\r
-				"Content-Type: text/plain\r\n" +
+				Content-Disposition: form-data; name="file1"; filename="a.txt"\r
-				"\r\n" +
+				Content-Type: text/plain\r
-				"Content of a.txt.\r\n" +
+				\r
-				"\r\n" +
+				Content of a.txt.\r
-				"-----------------------------9051914041544843365972754266\r\n" +
+				\r
-				"Content-Disposition: form-data; name=\"file2\"; filename=\"a.html\"\r\n" +
+				-----------------------------9051914041544843365972754266\r
-				"Content-Type: text/html\r\n" +
+				Content-Disposition: form-data; name="file2"; filename="a.html"\r
-				"\r\n" +
+				Content-Type: text/html\r
-				"<!DOCTYPE html><title>Content of a.html.</title>\r\n" +
+				\r
-				"\r\n" +
+				<!DOCTYPE html><title>Content of a.html.</title>\r
-				"-----------------------------9051914041544843365972754266--\r\n";
+				\r
+				-----------------------------9051914041544843365972754266--\r
+				""";
 
 		byte[] bytes = bodyContents.getBytes(StandardCharsets.UTF_8);
 		DefaultDataBuffer dataBuffer = DefaultDataBufferFactory.sharedInstance.wrap(ByteBuffer.wrap(bytes));

spring-webflux/src/test/java/org/springframework/web/reactive/function/client/WebClientIntegrationTests.java

@@ -726,8 +726,8 @@ class WebClientIntegrationTests {
 			ByteArrayOutputStream bos = new ByteArrayOutputStream();
 			try {
 				request.getBody().copyTo(bos);
-				String actual = bos.toString("UTF-8");
+				String actual = bos.toString(StandardCharsets.UTF_8);
-				String expected = new String(Files.readAllBytes(resource.getFile().toPath()), StandardCharsets.UTF_8);
+				String expected = Files.readString(resource.getFile().toPath(), StandardCharsets.UTF_8);
 				assertThat(actual).isEqualTo(expected);
 			}
 			catch (IOException ex) {

spring-webflux/src/test/java/org/springframework/web/reactive/function/server/DefaultServerRequestTests.java

@@ -412,15 +412,17 @@ public class DefaultServerRequestTests {
 
 	@Test
 	public void multipartData() {
-		String data = "--12345\r\n" +
+		String data = """
-				"Content-Disposition: form-data; name=\"foo\"\r\n" +
+				--12345\r
-				"\r\n" +
+				Content-Disposition: form-data; name="foo"\r
-				"bar\r\n" +
+				\r
-				"--12345\r\n" +
+				bar\r
-				"Content-Disposition: form-data; name=\"baz\"\r\n" +
+				--12345\r
-				"\r\n" +
+				Content-Disposition: form-data; name="baz"\r
-				"qux\r\n" +
+				\r
-				"--12345--\r\n";
+				qux\r
+				--12345--\r
+				""";
 		byte[] bytes = data.getBytes(StandardCharsets.UTF_8);
 		DefaultDataBuffer dataBuffer = DefaultDataBufferFactory.sharedInstance.wrap(ByteBuffer.wrap(bytes));
 		Flux<DataBuffer> body = Flux.just(dataBuffer);

spring-webflux/src/test/java/org/springframework/web/reactive/resource/CssLinkResourceTransformerTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2022 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.
@@ -80,13 +80,17 @@ public class CssLinkResourceTransformerTests {
 
 		MockServerWebExchange exchange = MockServerWebExchange.from(get("/static/main.css"));
 		Resource css = getResource("main.css");
-		String expected = "\n" +
+		String expected = """
-				"@import url(\"/static/bar-11e16cf79faee7ac698c805cf28248d2.css?#iefix\");\n" +
+
-				"@import url('/static/bar-11e16cf79faee7ac698c805cf28248d2.css#bla-normal');\n" +
+				@import url("/static/bar-11e16cf79faee7ac698c805cf28248d2.css?#iefix");
-				"@import url(/static/bar-11e16cf79faee7ac698c805cf28248d2.css);\n\n" +
+				@import url('/static/bar-11e16cf79faee7ac698c805cf28248d2.css#bla-normal');
-				"@import \"/static/foo-e36d2e05253c6c7085a91522ce43a0b4.css\";\n" +
+				@import url(/static/bar-11e16cf79faee7ac698c805cf28248d2.css);
-				"@import '/static/foo-e36d2e05253c6c7085a91522ce43a0b4.css';\n\n" +
+
-				"body { background: url(\"/static/images/image-f448cd1d5dba82b774f3202c878230b3.png?#iefix\") }\n";
+				@import "/static/foo-e36d2e05253c6c7085a91522ce43a0b4.css";
+				@import '/static/foo-e36d2e05253c6c7085a91522ce43a0b4.css';
+
+				body { background: url("/static/images/image-f448cd1d5dba82b774f3202c878230b3.png?#iefix") }
+				""";
 
 		StepVerifier.create(this.transformerChain.transform(exchange, css)
 				.cast(TransformedResource.class))
@@ -118,9 +122,10 @@ public class CssLinkResourceTransformerTests {
 		ResourceTransformerChain chain = new DefaultResourceTransformerChain(mockChain, transformers);
 
 		Resource resource = getResource("external.css");
-		String expected = "@import url(\"https://example.org/fonts/css\");\n" +
+		String expected = """
-				"body { background: url(\"file:///home/spring/image.png\") }\n" +
+				@import url("https://example.org/fonts/css");
-				"figure { background: url(\"//example.org/style.css\")}";
+				body { background: url("file:///home/spring/image.png") }
+				figure { background: url("//example.org/style.css")}""";
 
 		StepVerifier.create(chain.transform(exchange, resource)
 				.cast(TransformedResource.class))
@@ -167,10 +172,10 @@ public class CssLinkResourceTransformerTests {
 	public void transformEmptyUrlFunction() throws Exception {
 		MockServerWebExchange exchange = MockServerWebExchange.from(get("/static/empty_url_function.css"));
 		Resource css = getResource("empty_url_function.css");
-		String expected =
+		String expected = """
-				".fooStyle {\n" +
+						.fooStyle {
-				"\tbackground: transparent url() no-repeat left top;\n" +
+						\tbackground: transparent url() no-repeat left top;
-				"}";
+						}""";
 
 		StepVerifier.create(this.transformerChain.transform(exchange, css)
 				.cast(TransformedResource.class))

spring-webflux/src/test/java/org/springframework/web/reactive/result/view/freemarker/FreeMarkerMacroTests.java

@@ -45,7 +45,6 @@ import org.springframework.web.server.ServerWebExchange;
 import org.springframework.web.testfixture.http.server.reactive.MockServerHttpRequest;
 import org.springframework.web.testfixture.server.MockServerWebExchange;
 
-import static java.nio.charset.StandardCharsets.UTF_8;
 import static java.util.Collections.singletonMap;
 import static java.util.stream.Collectors.toList;
 import static org.assertj.core.api.Assertions.assertThat;
@@ -357,8 +356,9 @@ public class FreeMarkerMacroTests {
 	}
 
 	private void storeTemplateInTempDir(String macro) throws IOException {
-		Files.write(this.templateLoaderPath.resolve("tmp.ftl"),
+		Files.writeString(this.templateLoaderPath.resolve("tmp.ftl"),
-				("<#import \"spring.ftl\" as spring />\n" + macro).getBytes(UTF_8));
+				"<#import \"spring.ftl\" as spring />\n" + macro
+		);
 	}
 
 	private List<String> getOutput() {

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/ReactiveTypeHandler.java

@@ -381,8 +381,7 @@ class ReactiveTypeHandler {
 
 		@Override
 		protected void send(Object element) throws IOException {
-			if (element instanceof ServerSentEvent) {
+			if (element instanceof ServerSentEvent<?> event) {
-				ServerSentEvent<?> event = (ServerSentEvent<?>) element;
 				((SseEmitter) getEmitter()).send(adapt(event));
 			}
 			else {

spring-webmvc/src/main/java/org/springframework/web/servlet/tags/form/AbstractMultiCheckedElementTag.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2022 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.
@@ -223,16 +223,14 @@ public abstract class AbstractMultiCheckedElementTag extends AbstractCheckedElem
 				writeObjectEntry(tagWriter, valueProperty, labelProperty, item, i);
 			}
 		}
-		else if (itemsObject instanceof Collection) {
+		else if (itemsObject instanceof final Collection<?> optionCollection) {
-			final Collection<?> optionCollection = (Collection<?>) itemsObject;
 			int itemIndex = 0;
 			for (Iterator<?> it = optionCollection.iterator(); it.hasNext(); itemIndex++) {
 				Object item = it.next();
 				writeObjectEntry(tagWriter, valueProperty, labelProperty, item, itemIndex);
 			}
 		}
-		else if (itemsObject instanceof Map) {
+		else if (itemsObject instanceof final Map<?, ?> optionMap) {
-			final Map<?, ?> optionMap = (Map<?, ?>) itemsObject;
 			int itemIndex = 0;
 			for (Iterator it = optionMap.entrySet().iterator(); it.hasNext(); itemIndex++) {
 				Map.Entry entry = (Map.Entry) it.next();

spring-webmvc/src/main/java/org/springframework/web/servlet/view/RedirectView.java

@@ -537,8 +537,7 @@ public class RedirectView extends AbstractUrlBasedView implements SmartView {
 			}
 			return true;
 		}
-		if (value instanceof Collection) {
+		if (value instanceof Collection<?> coll) {
-			Collection<?> coll = (Collection<?>) value;
 			if (coll.isEmpty()) {
 				return false;
 			}

spring-webmvc/src/test/java/org/springframework/web/servlet/function/SseServerResponseTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2021 the original author or authors.
+ * Copyright 2002-2022 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.
@@ -109,12 +109,15 @@ class SseServerResponseTests {
 		ModelAndView mav = response.writeTo(this.mockRequest, this.mockResponse, context);
 		assertThat(mav).isNull();
 
-		String expected = "id:id\n" +
+		String expected = """
-				"event:name\n" +
+				id:id
-				":comment line 1\n" +
+				event:name
-				":comment line 2\n" +
+				:comment line 1
-				"retry:1000\n" +
+				:comment line 2
-				"data:data\n\n";
+				retry:1000
+				data:data
+
+				""";
 		assertThat(this.mockResponse.getContentAsString()).isEqualTo(expected);
 	}
 

spring-webmvc/src/test/java/org/springframework/web/servlet/function/ToStringVisitorTests.java

@@ -52,11 +52,12 @@ public class ToStringVisitorTests {
 		routerFunction.accept(visitor);
 		String result = visitor.toString();
 
-		String expected = "/foo => {\n" +
+		String expected = """
-				" /bar => {\n" +
+				/foo => {
-				"  (GET && /baz) -> \n" +
+					/bar => {
-				" }\n" +
+						(GET && /baz) ->\s
-				"}";
+					}
+				}""".replace('\t', ' ');
 		assertThat(result).isEqualTo(expected);
 	}
 

spring-webmvc/src/test/java/org/springframework/web/servlet/resource/CssLinkResourceTransformerTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2022 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.
@@ -84,13 +84,17 @@ public class CssLinkResourceTransformerTests {
 	public void transform() throws Exception {
 		this.request = new MockHttpServletRequest("GET", "/static/main.css");
 		Resource css = getResource("main.css");
-		String expected = "\n" +
+		String expected = """
-				"@import url(\"/static/bar-11e16cf79faee7ac698c805cf28248d2.css?#iefix\");\n" +
+
-				"@import url('/static/bar-11e16cf79faee7ac698c805cf28248d2.css#bla-normal');\n" +
+				@import url("/static/bar-11e16cf79faee7ac698c805cf28248d2.css?#iefix");
-				"@import url(/static/bar-11e16cf79faee7ac698c805cf28248d2.css);\n\n" +
+				@import url('/static/bar-11e16cf79faee7ac698c805cf28248d2.css#bla-normal');
-				"@import \"/static/foo-e36d2e05253c6c7085a91522ce43a0b4.css\";\n" +
+				@import url(/static/bar-11e16cf79faee7ac698c805cf28248d2.css);
-				"@import '/static/foo-e36d2e05253c6c7085a91522ce43a0b4.css';\n\n" +
+
-				"body { background: url(\"/static/images/image-f448cd1d5dba82b774f3202c878230b3.png?#iefix\") }\n";
+				@import "/static/foo-e36d2e05253c6c7085a91522ce43a0b4.css";
+				@import '/static/foo-e36d2e05253c6c7085a91522ce43a0b4.css';
+
+				body { background: url("/static/images/image-f448cd1d5dba82b774f3202c878230b3.png?#iefix") }
+				""";
 
 		TransformedResource actual = (TransformedResource) this.transformerChain.transform(this.request, css);
 		String result = new String(actual.getByteArray(), StandardCharsets.UTF_8);
@@ -115,9 +119,10 @@ public class CssLinkResourceTransformerTests {
 		ResourceTransformerChain chain = new DefaultResourceTransformerChain(mockChain, transformers);
 
 		Resource resource = getResource("external.css");
-		String expected = "@import url(\"https://example.org/fonts/css\");\n" +
+		String expected = """
-				"body { background: url(\"file:///home/spring/image.png\") }\n" +
+				@import url("https://example.org/fonts/css");
-				"figure { background: url(\"//example.org/style.css\")}";
+				body { background: url("file:///home/spring/image.png") }
+				figure { background: url("//example.org/style.css")}""";
 
 		TransformedResource transformedResource = (TransformedResource) chain.transform(this.request, resource);
 		String result = new String(transformedResource.getByteArray(), StandardCharsets.UTF_8);
@@ -155,10 +160,10 @@ public class CssLinkResourceTransformerTests {
 	public void transformEmptyUrlFunction() throws Exception {
 		this.request = new MockHttpServletRequest("GET", "/static/empty_url_function.css");
 		Resource css = getResource("empty_url_function.css");
-		String expected =
+		String expected = """
-				".fooStyle {\n" +
+						.fooStyle {
-				"\tbackground: transparent url() no-repeat left top;\n" +
+						\tbackground: transparent url() no-repeat left top;
-				"}";
+						}""";
 
 		TransformedResource actual = (TransformedResource) this.transformerChain.transform(this.request, css);
 		String result = new String(actual.getByteArray(), StandardCharsets.UTF_8);

spring-webmvc/src/test/java/org/springframework/web/servlet/view/freemarker/FreeMarkerMacroTests.java

@@ -48,7 +48,6 @@ import org.springframework.web.testfixture.servlet.MockHttpServletRequest;
 import org.springframework.web.testfixture.servlet.MockHttpServletResponse;
 import org.springframework.web.testfixture.servlet.MockServletContext;
 
-import static java.nio.charset.StandardCharsets.UTF_8;
 import static org.assertj.core.api.Assertions.assertThat;
 
 /**
@@ -346,8 +345,9 @@ public class FreeMarkerMacroTests {
 	}
 
 	private void storeTemplateInTempDir(String macro) throws IOException {
-		Files.write(this.templateLoaderPath.resolve("tmp.ftl"),
+		Files.writeString(this.templateLoaderPath.resolve("tmp.ftl"),
-				("<#import \"spring.ftl\" as spring />\n" + macro).getBytes(UTF_8));
+				"<#import \"spring.ftl\" as spring />\n" + macro
+		);
 	}
 
 	private String getOutput() throws IOException {

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

@@ -427,7 +427,7 @@ public class StompSubProtocolHandler implements SubProtocolHandler, ApplicationE
 	@Override
 	@SuppressWarnings("unchecked")
 	public void handleMessageToClient(WebSocketSession session, Message<?> message) {
-		if (!(message.getPayload() instanceof byte[])) {
+		if (!(message.getPayload() instanceof byte[] payload)) {
 			if (logger.isErrorEnabled()) {
 				logger.error("Expected byte[] payload. Ignoring " + message + ".");
 			}
@@ -464,7 +464,6 @@ public class StompSubProtocolHandler implements SubProtocolHandler, ApplicationE
 			}
 		}
 
-		byte[] payload = (byte[]) message.getPayload();
 		if (StompCommand.ERROR.equals(command) && getErrorHandler() != null) {
 			Message<byte[]> errorMessage = getErrorHandler().handleErrorMessageToClient((Message<byte[]>) message);
 			if (errorMessage != null) {

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

@@ -229,19 +229,14 @@ public abstract class AbstractClientSockJsSession implements WebSocketSession {
 	public void handleFrame(String payload) {
 		SockJsFrame frame = new SockJsFrame(payload);
 		switch (frame.getType()) {
-			case OPEN:
+			case OPEN -> handleOpenFrame();
-				handleOpenFrame();
+			case HEARTBEAT -> {
-				break;
-			case HEARTBEAT:
 				if (logger.isTraceEnabled()) {
 					logger.trace("Received heartbeat in " + this);
 				}
-				break;
+			}
-			case MESSAGE:
+			case MESSAGE -> handleMessageFrame(frame);
-				handleMessageFrame(frame);
+			case CLOSE -> handleCloseFrame(frame);
-				break;
-			case CLOSE:
-				handleCloseFrame(frame);
 		}
 	}
 

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

@@ -276,12 +276,11 @@ public class TransportHandlingSockJsService extends AbstractSockJsService implem
 			SockJsSession session = this.sessions.get(sessionId);
 			boolean isNewSession = false;
 			if (session == null) {
-				if (transportHandler instanceof SockJsSessionFactory) {
+				if (transportHandler instanceof SockJsSessionFactory sessionFactory) {
 					Map<String, Object> attributes = new HashMap<>();
 					if (!chain.applyBeforeHandshake(request, response, attributes)) {
 						return;
 					}
-					SockJsSessionFactory sessionFactory = (SockJsSessionFactory) transportHandler;
 					session = createSockJsSession(sessionId, sessionFactory, handler, attributes);
 					isNewSession = true;
 				}