Refine null-safety in spring-webmvc

See gh-32475

spring-webmvc/src/main/java/org/springframework/web/servlet/config/ResourcesBeanDefinitionParser.java

@@ -86,6 +86,7 @@ class ResourcesBeanDefinitionParser implements BeanDefinitionParser {
 
 
 	@Override
+	@Nullable
 	public BeanDefinition parse(Element element, ParserContext context) {
 		Object source = context.extractSource(element);
 

spring-webmvc/src/main/java/org/springframework/web/servlet/config/ViewControllerBeanDefinitionParser.java

@@ -60,6 +60,7 @@ class ViewControllerBeanDefinitionParser implements BeanDefinitionParser {
 
 
 	@Override
+	@Nullable
 	@SuppressWarnings("unchecked")
 	public BeanDefinition parse(Element element, ParserContext parserContext) {
 		Object source = parserContext.extractSource(element);

spring-webmvc/src/main/java/org/springframework/web/servlet/config/ViewResolversBeanDefinitionParser.java

@@ -29,6 +29,7 @@
 import org.springframework.beans.factory.xml.BeanDefinitionParser;
 import org.springframework.beans.factory.xml.ParserContext;
 import org.springframework.core.Ordered;
+import org.springframework.lang.Nullable;
 import org.springframework.util.xml.DomUtils;
 import org.springframework.web.servlet.view.BeanNameViewResolver;
 import org.springframework.web.servlet.view.ContentNegotiatingViewResolver;
@@ -68,6 +69,7 @@ public class ViewResolversBeanDefinitionParser implements BeanDefinitionParser {
 
 
 	@Override
+	@Nullable
 	public BeanDefinition parse(Element element, ParserContext context) {
 		Object source = context.extractSource(element);
 		context.pushContainingComponent(new CompositeComponentDefinition(element.getTagName(), source));

spring-webmvc/src/main/java/org/springframework/web/servlet/config/annotation/WebMvcConfigurerComposite.java

@@ -160,6 +160,7 @@ public void extendHandlerExceptionResolvers(List<HandlerExceptionResolver> excep
 	}
 
 	@Override
+	@Nullable
 	public Validator getValidator() {
 		Validator selected = null;
 		for (WebMvcConfigurer configurer : this.delegates) {

spring-webmvc/src/main/java/org/springframework/web/servlet/function/AbstractServerResponse.java

@@ -82,6 +82,7 @@ public MultiValueMap<String, Cookie> cookies() {
 	}
 
 	@Override
+	@Nullable
 	public ModelAndView writeTo(HttpServletRequest request, HttpServletResponse response,
 			Context context) throws ServletException, IOException {
 

spring-webmvc/src/main/java/org/springframework/web/servlet/function/DefaultEntityResponseBuilder.java

@@ -264,6 +264,7 @@ public T entity() {
 		}
 
 		@Override
+		@Nullable
 		protected ModelAndView writeToInternal(HttpServletRequest servletRequest,
 				HttpServletResponse servletResponse, Context context)
 				throws ServletException, IOException {
@@ -363,6 +364,7 @@ public CompletionStageEntityResponse(HttpStatusCode statusCode, HttpHeaders head
 		}
 
 		@Override
+		@Nullable
 		protected ModelAndView writeToInternal(HttpServletRequest servletRequest, HttpServletResponse servletResponse,
 				Context context) throws ServletException, IOException {
 
@@ -416,6 +418,7 @@ public PublisherEntityResponse(HttpStatusCode statusCode, HttpHeaders headers,
 		}
 
 		@Override
+		@Nullable
 		protected ModelAndView writeToInternal(HttpServletRequest servletRequest, HttpServletResponse servletResponse,
 				Context context) throws ServletException, IOException {
 

spring-webmvc/src/main/java/org/springframework/web/servlet/function/DefaultServerResponseBuilder.java

@@ -35,6 +35,7 @@
 import org.springframework.http.HttpMethod;
 import org.springframework.http.HttpStatusCode;
 import org.springframework.http.MediaType;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.LinkedMultiValueMap;
 import org.springframework.util.MultiValueMap;
@@ -229,6 +230,7 @@ public WriteFunctionResponse(HttpStatusCode statusCode, HttpHeaders headers, Mul
 		}
 
 		@Override
+		@Nullable
 		protected ModelAndView writeToInternal(HttpServletRequest request, HttpServletResponse response,
 				Context context) throws Exception {
 

spring-webmvc/src/main/java/org/springframework/web/servlet/handler/AbstractHandlerMethodMapping.java

@@ -483,6 +483,7 @@ protected boolean hasCorsConfigurationSource(Object handler) {
 	}
 
 	@Override
+	@Nullable
 	protected CorsConfiguration getCorsConfiguration(Object handler, HttpServletRequest request) {
 		CorsConfiguration corsConfig = super.getCorsConfiguration(handler, request);
 		if (handler instanceof HandlerMethod handlerMethod) {
@@ -600,6 +601,7 @@ public List<T> getMappingsByDirectPath(String urlPath) {
 		/**
 		 * Return handler methods by mapping name. Thread-safe for concurrent use.
 		 */
+		@Nullable
 		public List<HandlerMethod> getHandlerMethodsByMappingName(String mappingName) {
 			return this.nameLookup.get(mappingName);
 		}

spring-webmvc/src/main/java/org/springframework/web/servlet/handler/HandlerMappingIntrospector.java

@@ -500,6 +500,7 @@ public void setAttribute(String name, Object value) {
 		}
 
 		@Override
+		@Nullable
 		public Object getAttribute(String name) {
 			return this.attributes.get(name);
 		}
@@ -532,6 +533,7 @@ private static class LookupPathMatchableHandlerMapping implements MatchableHandl
 		}
 
 		@Override
+		@Nullable
 		public PathPatternParser getPatternParser() {
 			return this.delegate.getPatternParser();
 		}

spring-webmvc/src/main/java/org/springframework/web/servlet/i18n/FixedLocaleResolver.java

@@ -88,6 +88,7 @@ public Locale getLocale() {
 				return getDefaultLocale();
 			}
 			@Override
+			@Nullable
 			public TimeZone getTimeZone() {
 				return getDefaultTimeZone();
 			}

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/ParameterizableViewController.java

@@ -149,6 +149,7 @@ public boolean isStatusOnly() {
 	 * @see #getViewName()
 	 */
 	@Override
+	@Nullable
 	protected ModelAndView handleRequestInternal(HttpServletRequest request, HttpServletResponse response)
 			throws Exception {
 

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/ServletForwardingController.java

@@ -119,6 +119,7 @@ public void setBeanName(String name) {
 
 
 	@Override
+	@Nullable
 	protected ModelAndView handleRequestInternal(HttpServletRequest request, HttpServletResponse response)
 			throws Exception {
 

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/ServletWrappingController.java

@@ -159,6 +159,7 @@ public void afterPropertiesSet() throws Exception {
 	 * @see jakarta.servlet.Servlet#service(jakarta.servlet.ServletRequest, jakarta.servlet.ServletResponse)
 	 */
 	@Override
+	@Nullable
 	protected ModelAndView handleRequestInternal(HttpServletRequest request, HttpServletResponse response)
 			throws Exception {
 

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

@@ -61,7 +61,7 @@ public class ResponseStatusExceptionResolver extends AbstractHandlerExceptionRes
 
 
 	@Override
-	public void setMessageSource(MessageSource messageSource) {
+	public void setMessageSource(@Nullable MessageSource messageSource) {
 		this.messageSource = messageSource;
 	}
 

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

@@ -106,6 +106,7 @@ protected Set<String> getDirectPaths(RequestMappingInfo info) {
 	 * @return an info in case of a match; or {@code null} otherwise.
 	 */
 	@Override
+	@Nullable
 	protected RequestMappingInfo getMatchingMapping(RequestMappingInfo info, HttpServletRequest request) {
 		return info.getMatchingCondition(request);
 	}
@@ -243,6 +244,7 @@ private Map<String, MultiValueMap<String, String>> extractMatrixVariables(
 	 * but not by consumable/producible media types
 	 */
 	@Override
+	@Nullable
 	protected HandlerMethod handleNoMatch(
 			Set<RequestMappingInfo> infos, String lookupPath, HttpServletRequest request) throws ServletException {
 

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

@@ -37,6 +37,7 @@ public boolean supportsParameter(MethodParameter parameter) {
 	}
 
 	@Override
+	@Nullable
 	public Object resolveArgument(MethodParameter parameter, @Nullable ModelAndViewContainer mavContainer,
 			NativeWebRequest webRequest, @Nullable WebDataBinderFactory binderFactory) throws Exception {
 

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

@@ -112,6 +112,7 @@ private static class ExtendedServletRequestValueResolver extends ServletRequestV
 		}
 
 		@Override
+		@Nullable
 		protected Object getRequestParameter(String name, Class<?> type) {
 			Object value = super.getRequestParameter(name, type);
 			if (value == null) {

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

@@ -805,6 +805,7 @@ protected boolean supportsInternal(HandlerMethod handlerMethod) {
 	}
 
 	@Override
+	@Nullable
 	protected ModelAndView handleInternal(HttpServletRequest request,
 			HttpServletResponse response, HandlerMethod handlerMethod) throws Exception {
 

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

@@ -523,6 +523,7 @@ private void updateConsumesCondition(RequestMappingInfo info, Method method) {
 	}
 
 	@Override
+	@Nullable
 	public RequestMatchResult match(HttpServletRequest request, String pattern) {
 		Assert.state(getPatternParser() == null, "This HandlerMapping uses PathPatterns.");
 		RequestMappingInfo info = RequestMappingInfo.paths(pattern).options(this.config).build();
@@ -535,6 +536,7 @@ public RequestMatchResult match(HttpServletRequest request, String pattern) {
 	}
 
 	@Override
+	@Nullable
 	protected CorsConfiguration initCorsConfiguration(Object handler, Method method, RequestMappingInfo mappingInfo) {
 		HandlerMethod handlerMethod = createHandlerMethod(handler, method);
 		Class<?> beanType = handlerMethod.getBeanType();

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

@@ -127,6 +127,7 @@ public boolean supportsReturnType(MethodParameter returnType) {
 	 * converter to read the content with.
 	 */
 	@Override
+	@Nullable
 	public Object resolveArgument(MethodParameter parameter, @Nullable ModelAndViewContainer mavContainer,
 			NativeWebRequest webRequest, @Nullable WebDataBinderFactory binderFactory) throws Exception {
 
@@ -152,6 +153,7 @@ public Object resolveArgument(MethodParameter parameter, @Nullable ModelAndViewC
 	}
 
 	@Override
+	@Nullable
 	protected <T> Object readWithMessageConverters(NativeWebRequest webRequest, MethodParameter parameter,
 			Type paramType) throws IOException, HttpMediaTypeNotSupportedException, HttpMessageNotReadableException {
 

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

@@ -253,6 +253,7 @@ public MethodParameter getReturnValueType(@Nullable Object returnValue) {
 		 * Bridge to controller method-level annotations.
 		 */
 		@Override
+		@Nullable
 		public <A extends Annotation> A getMethodAnnotation(Class<A> annotationType) {
 			return ServletInvocableHandlerMethod.this.getMethodAnnotation(annotationType);
 		}

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

@@ -85,6 +85,7 @@ public boolean supportsParameter(MethodParameter parameter) {
 	}
 
 	@Override
+	@Nullable
 	public Object resolveArgument(MethodParameter parameter, @Nullable ModelAndViewContainer mavContainer,
 			NativeWebRequest webRequest, @Nullable WebDataBinderFactory binderFactory) throws Exception {
 

spring-webmvc/src/main/java/org/springframework/web/servlet/support/JspAwareRequestContext.java

@@ -95,6 +95,7 @@ protected Locale getFallbackLocale() {
 	 * request, session or application scope; if not found, returns {@code null}.
 	 */
 	@Override
+	@Nullable
 	protected TimeZone getFallbackTimeZone() {
 		if (jstlPresent) {
 			TimeZone timeZone = JstlPageLocaleResolver.getJstlTimeZone(getPageContext());

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

@@ -395,6 +395,7 @@ protected MessageSource getMessageSource() {
 	/**
 	 * Return default exception message.
 	 */
+	@Nullable
 	protected String getNoSuchMessageExceptionDescription(NoSuchMessageException ex) {
 		return ex.getMessage();
 	}

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

@@ -180,6 +180,7 @@ public String getElement() {
 	 * since we're dealing with multiple HTML elements.
 	 */
 	@Override
+	@Nullable
 	protected String resolveId() throws JspException {
 		Object id = evaluate("id", getId());
 		if (id != null) {

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

@@ -364,6 +364,7 @@ private void renderOption(Object value, String label, TagWriter tagWriter) throw
 	}
 
 	@Override
+	@Nullable
 	protected String autogenerateId() throws JspException {
 		return null;
 	}

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

@@ -323,6 +323,7 @@ protected int writeTagContent(TagWriter tagWriter) throws JspException {
 	 * since we're dealing with multiple HTML elements.
 	 */
 	@Override
+	@Nullable
 	protected String resolveId() throws JspException {
 		Object id = evaluate("id", getId());
 		if (id != null) {

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

@@ -200,6 +200,7 @@ public void afterPropertiesSet() throws BeansException {
 
 
 	@Override
+	@Nullable
 	protected View loadView(String viewName, Locale locale) throws Exception {
 		BeanFactory factory = initFactory(locale);
 		try {

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

@@ -461,6 +461,7 @@ protected Object getCacheKey(String viewName, Locale locale) {
 	 * @see #requiredViewClass
 	 */
 	@Override
+	@Nullable
 	protected View createView(String viewName, Locale locale) throws Exception {
 		// If this resolver is not supposed to handle the given view,
 		// return null to pass on to the next resolver in the chain.
@@ -545,6 +546,7 @@ protected AbstractUrlBasedView instantiateView() {
 	 * @see org.springframework.beans.factory.InitializingBean#afterPropertiesSet
 	 */
 	@Override
+	@Nullable
 	protected View loadView(String viewName, Locale locale) throws Exception {
 		AbstractUrlBasedView view = buildView(viewName);
 		View result = applyLifecycleMethods(viewName, view);

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

@@ -119,6 +119,7 @@ protected Object getCacheKey(String viewName, Locale locale) {
 	}
 
 	@Override
+	@Nullable
 	protected View loadView(String viewName, Locale locale) throws BeansException {
 		BeanFactory factory = initFactory();
 		try {

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

@@ -306,7 +306,7 @@ protected Class<?>[] getSourceTypes() {
 	 * @return the adapted XSLT Source
 	 * @throws IllegalArgumentException if the given Object is not of a supported type
 	 */
-	protected Source convertSource(Object sourceObject) throws Exception {
+	protected Source convertSource(@Nullable Object sourceObject) throws Exception {
 		if (sourceObject instanceof Source source) {
 			return source;
 		}