Specify generic type nullness in spring-web

See spring-projectsgh-34140

Author: sdeleuze

spring-web/src/main/java/org/springframework/http/RequestEntity.java

@@ -738,14 +738,14 @@ public static class UriTemplateRequestEntity<T> extends RequestEntity<T> {
 
 		private final String uriTemplate;
 
-		private final Object @Nullable [] uriVarsArray;
+		private final @Nullable Object @Nullable [] uriVarsArray;
 
-		private final @Nullable Map<String, ?> uriVarsMap;
+		private final @Nullable Map<String, ? extends @Nullable Object> uriVarsMap;
 
 		UriTemplateRequestEntity(
 				@Nullable T body, @Nullable HttpHeaders headers,
 				@Nullable HttpMethod method, @Nullable Type type, String uriTemplate,
-				Object @Nullable [] uriVarsArray, @Nullable Map<String, ?> uriVarsMap) {
+				@Nullable Object @Nullable [] uriVarsArray, @Nullable Map<String, ?> uriVarsMap) {
 
 			super(body, headers, method, null, type);
 			this.uriTemplate = uriTemplate;
@@ -757,11 +757,11 @@ public String getUriTemplate() {
 			return this.uriTemplate;
 		}
 
-		public Object @Nullable [] getVars() {
+		public @Nullable Object @Nullable [] getVars() {
 			return this.uriVarsArray;
 		}
 
-		public @Nullable Map<String, ?> getVarsMap() {
+		public @Nullable Map<String, ? extends @Nullable Object> getVarsMap() {
 			return this.uriVarsMap;
 		}
 

spring-web/src/main/java/org/springframework/http/converter/json/Jackson2ObjectMapperBuilder.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2024 the original author or authors.
+ * Copyright 2002-2025 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.
@@ -260,7 +260,7 @@ public Jackson2ObjectMapperBuilder annotationIntrospector(AnnotationIntrospector
 	 * @since 5.2.4
 	 */
 	public Jackson2ObjectMapperBuilder annotationIntrospector(
-			Function<AnnotationIntrospector, AnnotationIntrospector> pairingFunction) {
+			Function<@Nullable AnnotationIntrospector, @Nullable AnnotationIntrospector> pairingFunction) {
 
 		this.annotationIntrospector = pairingFunction.apply(this.annotationIntrospector);
 		return this;

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2024 the original author or authors.
+ * Copyright 2002-2025 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.
@@ -56,7 +56,7 @@ public class RestClientResponseException extends RestClientException {
 
 	private final @Nullable String responseCharset;
 
-	private transient @Nullable Function<ResolvableType, ?> bodyConvertFunction;
+	private transient @Nullable Function<ResolvableType, ? extends @Nullable Object> bodyConvertFunction;
 
 
 	/**
@@ -200,7 +200,7 @@ public String getResponseBodyAsString(Charset fallbackCharset) {
 	 * @param bodyConvertFunction the function to use
 	 * @since 6.0
 	 */
-	public void setBodyConvertFunction(Function<ResolvableType, ?> bodyConvertFunction) {
+	public void setBodyConvertFunction(Function<ResolvableType, ? extends @Nullable Object> bodyConvertFunction) {
 		this.bodyConvertFunction = bodyConvertFunction;
 	}
 

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2025 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.
@@ -99,7 +99,8 @@ else if (statusCode.is5xxServerError()) {
 				});
 	}
 
-	private static Function<ResolvableType, ?> initBodyConvertFunction(ClientHttpResponse response, byte[] body, List<HttpMessageConverter<?>> messageConverters) {
+	@SuppressWarnings("NullAway")
+	private static Function<ResolvableType, ? extends @Nullable Object> initBodyConvertFunction(ClientHttpResponse response, byte[] body, List<HttpMessageConverter<?>> messageConverters) {
 		Assert.state(!CollectionUtils.isEmpty(messageConverters), "Expected message converters");
 		return resolvableType -> {
 			try {

spring-web/src/main/java/org/springframework/web/filter/FormContentFilter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2021 the original author or authors.
+ * Copyright 2002-2025 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.
@@ -159,7 +159,7 @@ public Enumeration<String> getParameterNames() {
 		}
 
 		@Override
-		public @Nullable String[] getParameterValues(String name) {
+		public String[] getParameterValues(String name) {
 			String[] parameterValues = super.getParameterValues(name);
 			List<String> formParam = this.formParams.get(name);
 			if (formParam == null) {

spring-web/src/main/java/org/springframework/web/method/HandlerMethod.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2024 the original author or authors.
+ * Copyright 2002-2025 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.
@@ -357,7 +357,7 @@ public String toString() {
 	 * beans, and others). {@code @Controller}'s that require proxying should prefer
 	 * class-based proxy mechanisms.
 	 */
-	protected void assertTargetBean(Method method, Object targetBean, Object[] args) {
+	protected void assertTargetBean(Method method, Object targetBean, @Nullable Object[] args) {
 		Class<?> methodDeclaringClass = method.getDeclaringClass();
 		Class<?> targetBeanClass = targetBean.getClass();
 		if (!methodDeclaringClass.isAssignableFrom(targetBeanClass)) {
@@ -369,11 +369,14 @@ protected void assertTargetBean(Method method, Object targetBean, Object[] args)
 		}
 	}
 
-	protected String formatInvokeError(String text, Object[] args) {
+	protected String formatInvokeError(String text, @Nullable Object[] args) {
 		String formattedArgs = IntStream.range(0, args.length)
-				.mapToObj(i -> (args[i] != null ?
-						"[" + i + "] [type=" + args[i].getClass().getName() + "] [value=" + args[i] + "]" :
-						"[" + i + "] [null]"))
+				.mapToObj(i -> {
+					Object arg = args[i];
+					return (arg != null ?
+							"[" + i + "] [type=" +arg.getClass().getName() + "] [value=" + arg + "]" :
+							"[" + i + "] [null]");
+				})
 				.collect(Collectors.joining(",\n", " ", " "));
 		return text + "\n" +
 				"Controller [" + getBeanType().getName() + "]\n" +

spring-web/src/main/java/org/springframework/web/method/annotation/ExceptionHandlerMethodResolver.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2024 the original author or authors.
+ * Copyright 2002-2025 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -24,6 +24,7 @@
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import java.util.Set;
 
 import org.jspecify.annotations.Nullable;
@@ -226,7 +227,7 @@ public boolean hasExceptionMappings() {
 	 * Return the {@link Method} mapped to the given exception type, or
 	 * {@link #NO_MATCHING_EXCEPTION_HANDLER} if none.
 	 */
-	private @Nullable ExceptionHandlerMappingInfo getMappedMethod(Class<? extends Throwable> exceptionType, MediaType mediaType) {
+	private ExceptionHandlerMappingInfo getMappedMethod(Class<? extends Throwable> exceptionType, MediaType mediaType) {
 		List<ExceptionMapping> matches = new ArrayList<>();
 		for (ExceptionMapping mappingInfo : this.mappedMethods.keySet()) {
 			if (mappingInfo.exceptionType().isAssignableFrom(exceptionType) && mappingInfo.mediaType().isCompatibleWith(mediaType)) {
@@ -237,7 +238,7 @@ public boolean hasExceptionMappings() {
 			if (matches.size() > 1) {
 				matches.sort(new ExceptionMapingComparator(exceptionType, mediaType));
 			}
-			return this.mappedMethods.get(matches.get(0));
+			return Objects.requireNonNull(this.mappedMethods.get(matches.get(0)));
 		}
 		else {
 			return NO_MATCHING_EXCEPTION_HANDLER;

spring-web/src/main/java/org/springframework/web/method/annotation/HandlerMethodValidator.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2024 the original author or authors.
+ * Copyright 2002-2025 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.
@@ -78,7 +78,7 @@ public Class<?>[] determineValidationGroups(Object target, Method method) {
 	@Override
 	public void applyArgumentValidation(
 			Object target, Method method, MethodParameter @Nullable [] parameters,
-			Object[] arguments, Class<?>[] groups) {
+			@Nullable Object[] arguments, Class<?>[] groups) {
 
 		MethodValidationResult result = validateArguments(target, method, parameters, arguments, groups);
 		if (!result.hasErrors()) {
@@ -110,7 +110,7 @@ public void applyArgumentValidation(
 	@Override
 	public MethodValidationResult validateArguments(
 			Object target, Method method, MethodParameter @Nullable [] parameters,
-			Object[] arguments, Class<?>[] groups) {
+			@Nullable Object[] arguments, Class<?>[] groups) {
 
 		return this.validationAdapter.validateArguments(target, method, parameters, arguments, groups);
 	}

spring-web/src/main/java/org/springframework/web/method/support/InvocableHandlerMethod.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2024 the original author or authors.
+ * Copyright 2002-2025 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.
@@ -172,9 +172,9 @@ public void setMethodValidator(@Nullable MethodValidator methodValidator) {
 	 * @see #doInvoke
 	 */
 	public @Nullable Object invokeForRequest(NativeWebRequest request, @Nullable ModelAndViewContainer mavContainer,
-			Object... providedArgs) throws Exception {
+			@Nullable Object... providedArgs) throws Exception {
 
-		Object[] args = getMethodArgumentValues(request, mavContainer, providedArgs);
+		@Nullable Object[] args = getMethodArgumentValues(request, mavContainer, providedArgs);
 		if (logger.isTraceEnabled()) {
 			logger.trace("Arguments: " + Arrays.toString(args));
 		}
@@ -200,15 +200,15 @@ public void setMethodValidator(@Nullable MethodValidator methodValidator) {
 	 * <p>The resulting array will be passed into {@link #doInvoke}.
 	 * @since 5.1.2
 	 */
-	protected Object[] getMethodArgumentValues(NativeWebRequest request, @Nullable ModelAndViewContainer mavContainer,
-			Object... providedArgs) throws Exception {
+	protected @Nullable Object[] getMethodArgumentValues(NativeWebRequest request, @Nullable ModelAndViewContainer mavContainer,
+			@Nullable Object... providedArgs) throws Exception {
 
 		MethodParameter[] parameters = getMethodParameters();
 		if (ObjectUtils.isEmpty(parameters)) {
 			return EMPTY_ARGS;
 		}
 
-		Object[] args = new Object[parameters.length];
+		@Nullable Object[] args = new Object[parameters.length];
 		for (int i = 0; i < parameters.length; i++) {
 			MethodParameter parameter = parameters[i];
 			parameter.initParameterNameDiscovery(this.parameterNameDiscoverer);
@@ -239,7 +239,7 @@ protected Object[] getMethodArgumentValues(NativeWebRequest request, @Nullable M
 	/**
 	 * Invoke the handler method with the given argument values.
 	 */
-	protected @Nullable Object doInvoke(Object... args) throws Exception {
+	protected @Nullable Object doInvoke(@Nullable Object... args) throws Exception {
 		Method method = getBridgedMethod();
 		try {
 			if (KotlinDetector.isKotlinReflectPresent()) {
@@ -285,7 +285,7 @@ else if (targetException instanceof Exception exception) {
 	 * instead.
 	 * @since 6.0
 	 */
-	protected Object invokeSuspendingFunction(Method method, Object target, Object[] args) {
+	protected Object invokeSuspendingFunction(Method method, Object target, @Nullable Object[] args) {
 		Object result = CoroutinesUtils.invokeSuspendingFunction(method, target, args);
 		return (result instanceof Mono<?> mono ? mono.handle(KotlinDelegate::handleResult) : result);
 	}
@@ -297,7 +297,9 @@ protected Object invokeSuspendingFunction(Method method, Object target, Object[]
 	private static class KotlinDelegate {
 
 		@SuppressWarnings("DataFlowIssue")
-		public static @Nullable Object invokeFunction(Method method, Object target, Object[] args) throws InvocationTargetException, IllegalAccessException, NoSuchMethodException {
+		public static @Nullable Object invokeFunction(Method method, Object target, @Nullable Object[] args) throws
+				InvocationTargetException, IllegalAccessException, NoSuchMethodException {
+
 			KFunction<?> function = ReflectJvmMapping.getKotlinFunction(method);
 			// For property accessors
 			if (function == null) {

spring-web/src/main/java/org/springframework/web/service/invoker/HttpServiceMethod.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2024 the original author or authors.
+ * Copyright 2002-2025 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.
@@ -127,13 +127,13 @@ public Method getMethod() {
 	}
 
 
-	public @Nullable Object invoke(Object[] arguments) {
+	public @Nullable Object invoke(@Nullable Object[] arguments) {
 		HttpRequestValues.Builder requestValues = this.requestValuesInitializer.initializeRequestValuesBuilder();
 		applyArguments(requestValues, arguments);
 		return this.responseFunction.execute(requestValues.build());
 	}
 
-	private void applyArguments(HttpRequestValues.Builder requestValues, Object[] arguments) {
+	private void applyArguments(HttpRequestValues.Builder requestValues, @Nullable Object[] arguments) {
 		Assert.isTrue(arguments.length == this.parameters.length, "Method argument mismatch");
 		for (int i = 0; i < arguments.length; i++) {
 			Object value = arguments[i];
@@ -383,10 +383,10 @@ private interface ResponseFunction {
 	}
 
 	private record ExchangeResponseFunction(
-			Function<HttpRequestValues, Object> responseFunction) implements ResponseFunction {
+			Function<HttpRequestValues, @Nullable Object> responseFunction) implements ResponseFunction {
 
 		@Override
-		public Object execute(HttpRequestValues requestValues) {
+		public @Nullable Object execute(HttpRequestValues requestValues) {
 			return this.responseFunction.apply(requestValues);
 		}
 
@@ -403,7 +403,7 @@ public static ResponseFunction create(HttpExchangeAdapter client, Method method)
 			MethodParameter param = new MethodParameter(method, -1).nestedIfOptional();
 			Class<?> paramType = param.getNestedParameterType();
 
-			Function<HttpRequestValues, Object> responseFunction;
+			Function<HttpRequestValues, @Nullable Object> responseFunction;
 			if (ClassUtils.isVoidType(paramType)) {
 				responseFunction = requestValues -> {
 					client.exchange(requestValues);

spring-web/src/main/java/org/springframework/web/service/invoker/HttpServiceProxyFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2024 the original author or authors.
+ * Copyright 2002-2025 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.
@@ -233,7 +233,7 @@ private HttpServiceMethodInterceptor(List<HttpServiceMethod> methods) {
 			Method method = invocation.getMethod();
 			HttpServiceMethod httpServiceMethod = this.httpServiceMethods.get(method);
 			if (httpServiceMethod != null) {
-				Object[] arguments = KotlinDetector.isSuspendingFunction(method) ?
+				@Nullable Object[] arguments = KotlinDetector.isSuspendingFunction(method) ?
 						resolveCoroutinesArguments(invocation.getArguments()) : invocation.getArguments();
 				return httpServiceMethod.invoke(arguments);
 			}
@@ -246,7 +246,7 @@ private HttpServiceMethodInterceptor(List<HttpServiceMethod> methods) {
 			throw new IllegalStateException("Unexpected method invocation: " + method);
 		}
 
-		private static Object[] resolveCoroutinesArguments(Object[] args) {
+		private static Object[] resolveCoroutinesArguments(@Nullable Object[] args) {
 			Object[] functionArgs = new Object[args.length - 1];
 			System.arraycopy(args, 0, functionArgs, 0, args.length - 1);
 			return functionArgs;

spring-web/src/main/java/org/springframework/web/util/DefaultUriBuilderFactory.java

@@ -140,6 +140,7 @@ public EncodingMode getEncodingMode() {
 	 * with a Map of variables.
 	 * @param defaultUriVariables default URI variable values
 	 */
+	@SuppressWarnings("NullAway") // https://github.com/uber/NullAway/issues/1126
 	public void setDefaultUriVariables(@Nullable Map<String, ? extends @Nullable Object> defaultUriVariables) {
 		if (defaultUriVariables != null) {
 			if (this.defaultUriVariables == null) {
@@ -431,6 +432,7 @@ public DefaultUriBuilder fragment(@Nullable String fragment) {
 		}
 
 		@Override
+		@SuppressWarnings("NullAway") // https://github.com/uber/NullAway/issues/1126
 		public URI build(Map<String, ?> uriVars) {
 			if (!CollectionUtils.isEmpty(defaultUriVariables)) {
 				Map<String, Object> map = new HashMap<>(defaultUriVariables.size() + uriVars.size());
@@ -446,6 +448,7 @@ public URI build(Map<String, ?> uriVars) {
 		}
 
 		@Override
+		@SuppressWarnings("NullAway") // https://github.com/uber/NullAway/issues/1126
 		public URI build(@Nullable Object... uriVars) {
 			if (ObjectUtils.isEmpty(uriVars) && !CollectionUtils.isEmpty(defaultUriVariables)) {
 				return build(Collections.emptyMap());