Leverage the nullability defined at type level

Signed-off-by: Tran Ngoc Nhan <ngocnhan.tran1996@gmail.com>

spring-webflux/src/main/java/org/springframework/web/reactive/result/method/annotation/ResponseEntityExceptionHandler.java

@@ -105,7 +105,7 @@ public abstract class ResponseEntityExceptionHandler implements MessageSourceAwa
 			ErrorResponseException.class,
 			MethodValidationException.class
 	})
-	public final Mono<ResponseEntity<Object>> handleException(Exception ex, ServerWebExchange exchange) {
+	public final Mono<ResponseEntity<@Nullable Object>> handleException(Exception ex, ServerWebExchange exchange) {
 		if (ex instanceof MethodNotAllowedException theEx) {
 			return handleMethodNotAllowedException(theEx, theEx.getHeaders(), theEx.getStatusCode(), exchange);
 		}
@@ -159,7 +159,7 @@ public abstract class ResponseEntityExceptionHandler implements MessageSourceAwa
 	 * @param exchange the current request and response
 	 * @return a {@code Mono} with the {@code ResponseEntity} for the response
 	 */
-	protected Mono<ResponseEntity<Object>> handleMethodNotAllowedException(
+	protected Mono<ResponseEntity<@Nullable Object>> handleMethodNotAllowedException(
 			MethodNotAllowedException ex, HttpHeaders headers, HttpStatusCode status,
 			ServerWebExchange exchange) {
 
@@ -175,7 +175,7 @@ public abstract class ResponseEntityExceptionHandler implements MessageSourceAwa
 	 * @param exchange the current request and response
 	 * @return a {@code Mono} with the {@code ResponseEntity} for the response
 	 */
-	protected Mono<ResponseEntity<Object>> handleNotAcceptableStatusException(
+	protected Mono<ResponseEntity<@Nullable Object>> handleNotAcceptableStatusException(
 			NotAcceptableStatusException ex, HttpHeaders headers, HttpStatusCode status,
 			ServerWebExchange exchange) {
 
@@ -191,7 +191,7 @@ public abstract class ResponseEntityExceptionHandler implements MessageSourceAwa
 	 * @param exchange the current request and response
 	 * @return a {@code Mono} with the {@code ResponseEntity} for the response
 	 */
-	protected Mono<ResponseEntity<Object>> handleUnsupportedMediaTypeStatusException(
+	protected Mono<ResponseEntity<@Nullable Object>> handleUnsupportedMediaTypeStatusException(
 			UnsupportedMediaTypeStatusException ex, HttpHeaders headers, HttpStatusCode status,
 			ServerWebExchange exchange) {
 
@@ -207,7 +207,7 @@ public abstract class ResponseEntityExceptionHandler implements MessageSourceAwa
 	 * @param exchange the current request and response
 	 * @return a {@code Mono} with the {@code ResponseEntity} for the response
 	 */
-	protected Mono<ResponseEntity<Object>> handleMissingRequestValueException(
+	protected Mono<ResponseEntity<@Nullable Object>> handleMissingRequestValueException(
 			MissingRequestValueException ex, HttpHeaders headers, HttpStatusCode status,
 			ServerWebExchange exchange) {
 
@@ -223,7 +223,7 @@ public abstract class ResponseEntityExceptionHandler implements MessageSourceAwa
 	 * @param exchange the current request and response
 	 * @return a {@code Mono} with the {@code ResponseEntity} for the response
 	 */
-	protected Mono<ResponseEntity<Object>> handleUnsatisfiedRequestParameterException(
+	protected Mono<ResponseEntity<@Nullable Object>> handleUnsatisfiedRequestParameterException(
 			UnsatisfiedRequestParameterException ex, HttpHeaders headers, HttpStatusCode status,
 			ServerWebExchange exchange) {
 
@@ -239,7 +239,7 @@ public abstract class ResponseEntityExceptionHandler implements MessageSourceAwa
 	 * @param exchange the current request and response
 	 * @return a {@code Mono} with the {@code ResponseEntity} for the response
 	 */
-	protected Mono<ResponseEntity<Object>> handleWebExchangeBindException(
+	protected Mono<ResponseEntity<@Nullable Object>> handleWebExchangeBindException(
 			WebExchangeBindException ex, HttpHeaders headers, HttpStatusCode status,
 			ServerWebExchange exchange) {
 
@@ -256,7 +256,7 @@ public abstract class ResponseEntityExceptionHandler implements MessageSourceAwa
 	 * @return a {@code Mono} with the {@code ResponseEntity} for the response
 	 * @since 6.1
 	 */
-	protected Mono<ResponseEntity<Object>> handleHandlerMethodValidationException(
+	protected Mono<ResponseEntity<@Nullable Object>> handleHandlerMethodValidationException(
 			HandlerMethodValidationException ex, HttpHeaders headers, HttpStatusCode status,
 			ServerWebExchange exchange) {
 
@@ -272,7 +272,7 @@ public abstract class ResponseEntityExceptionHandler implements MessageSourceAwa
 	 * @param exchange the current request and response
 	 * @return a {@code Mono} with the {@code ResponseEntity} for the response
 	 */
-	protected Mono<ResponseEntity<Object>> handleServerWebInputException(
+	protected Mono<ResponseEntity<@Nullable Object>> handleServerWebInputException(
 			ServerWebInputException ex, HttpHeaders headers, HttpStatusCode status,
 			ServerWebExchange exchange) {
 
@@ -288,7 +288,7 @@ public abstract class ResponseEntityExceptionHandler implements MessageSourceAwa
 	 * @param exchange the current request and response
 	 * @return a {@code Mono} with the {@code ResponseEntity} for the response
 	 */
-	protected Mono<ResponseEntity<Object>> handleResponseStatusException(
+	protected Mono<ResponseEntity<@Nullable Object>> handleResponseStatusException(
 			ResponseStatusException ex, HttpHeaders headers, HttpStatusCode status,
 			ServerWebExchange exchange) {
 
@@ -304,7 +304,7 @@ public abstract class ResponseEntityExceptionHandler implements MessageSourceAwa
 	 * @param exchange the current request and response
 	 * @return a {@code Mono} with the {@code ResponseEntity} for the response
 	 */
-	protected Mono<ResponseEntity<Object>> handleServerErrorException(
+	protected Mono<ResponseEntity<@Nullable Object>> handleServerErrorException(
 			ServerErrorException ex, HttpHeaders headers, HttpStatusCode status,
 			ServerWebExchange exchange) {
 
@@ -320,7 +320,7 @@ public abstract class ResponseEntityExceptionHandler implements MessageSourceAwa
 	 * @param exchange the current request and response
 	 * @return a {@code Mono} with the {@code ResponseEntity} for the response
 	 */
-	protected Mono<ResponseEntity<Object>> handleErrorResponseException(
+	protected Mono<ResponseEntity<@Nullable Object>> handleErrorResponseException(
 			ErrorResponseException ex, HttpHeaders headers, HttpStatusCode status,
 			ServerWebExchange exchange) {
 
@@ -336,7 +336,7 @@ public abstract class ResponseEntityExceptionHandler implements MessageSourceAwa
 	 * @return a {@code Mono} with the {@code ResponseEntity} for the response
 	 * @since 6.1
 	 */
-	protected Mono<ResponseEntity<Object>> handleMethodValidationException(
+	protected Mono<ResponseEntity<@Nullable Object>> handleMethodValidationException(
 			MethodValidationException ex, HttpStatus status, ServerWebExchange exchange) {
 
 		ProblemDetail body = createProblemDetail(ex, status, "Validation failed", null, null, exchange);
@@ -394,7 +394,7 @@ public abstract class ResponseEntityExceptionHandler implements MessageSourceAwa
 	 * @param exchange the current request and response
 	 * @return a {@code Mono} with the {@code ResponseEntity} for the response
 	 */
-	protected Mono<ResponseEntity<Object>> handleExceptionInternal(
+	protected Mono<ResponseEntity<@Nullable Object>> handleExceptionInternal(
 			Exception ex, @Nullable Object body, @Nullable HttpHeaders headers, HttpStatusCode status,
 			ServerWebExchange exchange) {
 
@@ -421,11 +421,11 @@ public abstract class ResponseEntityExceptionHandler implements MessageSourceAwa
 	 * @return a {@code Mono} with the created {@code ResponseEntity}
 	 * @since 6.0
 	 */
-	protected Mono<ResponseEntity<Object>> createResponseEntity(
+	protected Mono<ResponseEntity<@Nullable Object>> createResponseEntity(
 			@Nullable Object body, @Nullable HttpHeaders headers, HttpStatusCode status,
 			ServerWebExchange exchange) {
 
-		return Mono.just(new ResponseEntity<>(body, headers, status));
+		return Mono.just(new ResponseEntity<@Nullable Object>(body, headers, status));
 	}
 
 }

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

@@ -135,7 +135,7 @@ public abstract class ResponseEntityExceptionHandler implements MessageSourceAwa
 			MethodValidationException.class,
 			AsyncRequestNotUsableException.class
 		})
-	public final @Nullable ResponseEntity<Object> handleException(Exception ex, WebRequest request) throws Exception {
+	public final @Nullable ResponseEntity<@Nullable Object> handleException(Exception ex, WebRequest request) throws Exception {
 		if (ex instanceof HttpRequestMethodNotSupportedException subEx) {
 			return handleHttpRequestMethodNotSupported(subEx, subEx.getHeaders(), subEx.getStatusCode(), request);
 		}
@@ -219,7 +219,7 @@ public abstract class ResponseEntityExceptionHandler implements MessageSourceAwa
 	 * @return a {@code ResponseEntity} for the response to use, possibly
 	 * {@code null} when the response is already committed
 	 */
-	protected @Nullable ResponseEntity<Object> handleHttpRequestMethodNotSupported(
+	protected @Nullable ResponseEntity<@Nullable Object> handleHttpRequestMethodNotSupported(
 			HttpRequestMethodNotSupportedException ex, HttpHeaders headers, HttpStatusCode status, WebRequest request) {
 
 		pageNotFoundLogger.warn(ex.getMessage());
@@ -236,7 +236,7 @@ public abstract class ResponseEntityExceptionHandler implements MessageSourceAwa
 	 * @return a {@code ResponseEntity} for the response to use, possibly
 	 * {@code null} when the response is already committed
 	 */
-	protected @Nullable ResponseEntity<Object> handleHttpMediaTypeNotSupported(
+	protected @Nullable ResponseEntity<@Nullable Object> handleHttpMediaTypeNotSupported(
 			HttpMediaTypeNotSupportedException ex, HttpHeaders headers, HttpStatusCode status, WebRequest request) {
 
 		return handleExceptionInternal(ex, null, headers, status, request);
@@ -252,7 +252,7 @@ public abstract class ResponseEntityExceptionHandler implements MessageSourceAwa
 	 * @return a {@code ResponseEntity} for the response to use, possibly
 	 * {@code null} when the response is already committed
 	 */
-	protected @Nullable ResponseEntity<Object> handleHttpMediaTypeNotAcceptable(
+	protected @Nullable ResponseEntity<@Nullable Object> handleHttpMediaTypeNotAcceptable(
 			HttpMediaTypeNotAcceptableException ex, HttpHeaders headers, HttpStatusCode status, WebRequest request) {
 
 		return handleExceptionInternal(ex, null, headers, status, request);
@@ -269,7 +269,7 @@ public abstract class ResponseEntityExceptionHandler implements MessageSourceAwa
 	 * {@code null} when the response is already committed
 	 * @since 4.2
 	 */
-	protected @Nullable ResponseEntity<Object> handleMissingPathVariable(
+	protected @Nullable ResponseEntity<@Nullable Object> handleMissingPathVariable(
 			MissingPathVariableException ex, HttpHeaders headers, HttpStatusCode status, WebRequest request) {
 
 		return handleExceptionInternal(ex, null, headers, status, request);
@@ -285,7 +285,7 @@ public abstract class ResponseEntityExceptionHandler implements MessageSourceAwa
 	 * @return a {@code ResponseEntity} for the response to use, possibly
 	 * {@code null} when the response is already committed
 	 */
-	protected @Nullable ResponseEntity<Object> handleMissingServletRequestParameter(
+	protected @Nullable ResponseEntity<@Nullable Object> handleMissingServletRequestParameter(
 			MissingServletRequestParameterException ex, HttpHeaders headers, HttpStatusCode status, WebRequest request) {
 
 		return handleExceptionInternal(ex, null, headers, status, request);
@@ -301,7 +301,7 @@ public abstract class ResponseEntityExceptionHandler implements MessageSourceAwa
 	 * @return a {@code ResponseEntity} for the response to use, possibly
 	 * {@code null} when the response is already committed
 	 */
-	protected @Nullable ResponseEntity<Object> handleMissingServletRequestPart(
+	protected @Nullable ResponseEntity<@Nullable Object> handleMissingServletRequestPart(
 			MissingServletRequestPartException ex, HttpHeaders headers, HttpStatusCode status, WebRequest request) {
 
 		return handleExceptionInternal(ex, null, headers, status, request);
@@ -317,7 +317,7 @@ public abstract class ResponseEntityExceptionHandler implements MessageSourceAwa
 	 * @return a {@code ResponseEntity} for the response to use, possibly
 	 * {@code null} when the response is already committed
 	 */
-	protected @Nullable ResponseEntity<Object> handleServletRequestBindingException(
+	protected @Nullable ResponseEntity<@Nullable Object> handleServletRequestBindingException(
 			ServletRequestBindingException ex, HttpHeaders headers, HttpStatusCode status, WebRequest request) {
 
 		return handleExceptionInternal(ex, null, headers, status, request);
@@ -333,7 +333,7 @@ public abstract class ResponseEntityExceptionHandler implements MessageSourceAwa
 	 * @return a {@code ResponseEntity} for the response to use, possibly
 	 * {@code null} when the response is already committed
 	 */
-	protected @Nullable ResponseEntity<Object> handleMethodArgumentNotValid(
+	protected @Nullable ResponseEntity<@Nullable Object> handleMethodArgumentNotValid(
 			MethodArgumentNotValidException ex, HttpHeaders headers, HttpStatusCode status, WebRequest request) {
 
 		return handleExceptionInternal(ex, null, headers, status, request);
@@ -350,7 +350,7 @@ public abstract class ResponseEntityExceptionHandler implements MessageSourceAwa
 	 * {@code null} when the response is already committed
 	 * @since 6.1
 	 */
-	protected @Nullable ResponseEntity<Object> handleHandlerMethodValidationException(
+	protected @Nullable ResponseEntity<@Nullable Object> handleHandlerMethodValidationException(
 			HandlerMethodValidationException ex, HttpHeaders headers, HttpStatusCode status, WebRequest request) {
 
 		return handleExceptionInternal(ex, null, headers, status, request);
@@ -367,7 +367,7 @@ public abstract class ResponseEntityExceptionHandler implements MessageSourceAwa
 	 * {@code null} when the response is already committed
 	 * @since 4.0
 	 */
-	protected @Nullable ResponseEntity<Object> handleNoHandlerFoundException(
+	protected @Nullable ResponseEntity<@Nullable Object> handleNoHandlerFoundException(
 			NoHandlerFoundException ex, HttpHeaders headers, HttpStatusCode status, WebRequest request) {
 
 		return handleExceptionInternal(ex, null, headers, status, request);
@@ -384,7 +384,7 @@ public abstract class ResponseEntityExceptionHandler implements MessageSourceAwa
 	 * {@code null} when the response is already committed
 	 * @since 6.1
 	 */
-	protected @Nullable ResponseEntity<Object> handleNoResourceFoundException(
+	protected @Nullable ResponseEntity<@Nullable Object> handleNoResourceFoundException(
 			NoResourceFoundException ex, HttpHeaders headers, HttpStatusCode status, WebRequest request) {
 
 		return handleExceptionInternal(ex, null, headers, status, request);
@@ -401,7 +401,7 @@ public abstract class ResponseEntityExceptionHandler implements MessageSourceAwa
 	 * {@code null} when the response is already committed
 	 * @since 4.2.8
 	 */
-	protected @Nullable ResponseEntity<Object> handleAsyncRequestTimeoutException(
+	protected @Nullable ResponseEntity<@Nullable Object> handleAsyncRequestTimeoutException(
 			AsyncRequestTimeoutException ex, HttpHeaders headers, HttpStatusCode status, WebRequest request) {
 
 		return handleExceptionInternal(ex, null, headers, status, request);
@@ -418,7 +418,7 @@ public abstract class ResponseEntityExceptionHandler implements MessageSourceAwa
 	 * {@code null} when the response is already committed
 	 * @since 6.0
 	 */
-	protected @Nullable ResponseEntity<Object> handleErrorResponseException(
+	protected @Nullable ResponseEntity<@Nullable Object> handleErrorResponseException(
 			ErrorResponseException ex, HttpHeaders headers, HttpStatusCode status, WebRequest request) {
 
 		return handleExceptionInternal(ex, null, headers, status, request);
@@ -435,7 +435,7 @@ public abstract class ResponseEntityExceptionHandler implements MessageSourceAwa
 	 * {@code null} when the response is already committed
 	 * @since 6.1
 	 */
-	protected @Nullable ResponseEntity<Object> handleMaxUploadSizeExceededException(
+	protected @Nullable ResponseEntity<@Nullable Object> handleMaxUploadSizeExceededException(
 			MaxUploadSizeExceededException ex, HttpHeaders headers, HttpStatusCode status, WebRequest request) {
 
 		return handleExceptionInternal(ex, null, headers, status, request);
@@ -454,7 +454,7 @@ public abstract class ResponseEntityExceptionHandler implements MessageSourceAwa
 	 * @return a {@code ResponseEntity} for the response to use, possibly
 	 * {@code null} when the response is already committed
 	 */
-	protected @Nullable ResponseEntity<Object> handleConversionNotSupported(
+	protected @Nullable ResponseEntity<@Nullable Object> handleConversionNotSupported(
 			ConversionNotSupportedException ex, HttpHeaders headers, HttpStatusCode status, WebRequest request) {
 
 		Object[] args = {ex.getPropertyName(), ex.getValue()};
@@ -477,7 +477,7 @@ public abstract class ResponseEntityExceptionHandler implements MessageSourceAwa
 	 * @return a {@code ResponseEntity} for the response to use, possibly
 	 * {@code null} when the response is already committed
 	 */
-	protected @Nullable ResponseEntity<Object> handleTypeMismatch(
+	protected @Nullable ResponseEntity<@Nullable Object> handleTypeMismatch(
 			TypeMismatchException ex, HttpHeaders headers, HttpStatusCode status, WebRequest request) {
 
 		Object[] args = {ex.getPropertyName(), ex.getValue(),
@@ -502,7 +502,7 @@ public abstract class ResponseEntityExceptionHandler implements MessageSourceAwa
 	 * @return a {@code ResponseEntity} for the response to use, possibly
 	 * {@code null} when the response is already committed
 	 */
-	protected @Nullable ResponseEntity<Object> handleHttpMessageNotReadable(
+	protected @Nullable ResponseEntity<@Nullable Object> handleHttpMessageNotReadable(
 			HttpMessageNotReadableException ex, HttpHeaders headers, HttpStatusCode status, WebRequest request) {
 
 		ProblemDetail body = createProblemDetail(ex, status, "Failed to read request", null, null, request);
@@ -522,7 +522,7 @@ public abstract class ResponseEntityExceptionHandler implements MessageSourceAwa
 	 * @return a {@code ResponseEntity} for the response to use, possibly
 	 * {@code null} when the response is already committed
 	 */
-	protected @Nullable ResponseEntity<Object> handleHttpMessageNotWritable(
+	protected @Nullable ResponseEntity<@Nullable Object> handleHttpMessageNotWritable(
 			HttpMessageNotWritableException ex, HttpHeaders headers, HttpStatusCode status, WebRequest request) {
 
 		ProblemDetail body = createProblemDetail(ex, status, "Failed to write request", null, null, request);
@@ -543,7 +543,7 @@ public abstract class ResponseEntityExceptionHandler implements MessageSourceAwa
 	 * {@code null} when the response is already committed
 	 * @since 6.1
 	 */
-	protected @Nullable ResponseEntity<Object> handleMethodValidationException(
+	protected @Nullable ResponseEntity<@Nullable Object> handleMethodValidationException(
 			MethodValidationException ex, HttpHeaders headers, HttpStatus status, WebRequest request) {
 
 		ProblemDetail body = createProblemDetail(ex, status, "Validation failed", null, null, request);
@@ -559,7 +559,7 @@ public abstract class ResponseEntityExceptionHandler implements MessageSourceAwa
 	 * {@code null} when the response is already committed
 	 * @since 6.2
 	 */
-	protected @Nullable ResponseEntity<Object> handleAsyncRequestNotUsableException(
+	protected @Nullable ResponseEntity<@Nullable Object> handleAsyncRequestNotUsableException(
 			AsyncRequestNotUsableException ex, WebRequest request) {
 
 		return null;
@@ -614,7 +614,7 @@ public abstract class ResponseEntityExceptionHandler implements MessageSourceAwa
 	 * @return a {@code ResponseEntity} for the response to use, possibly
 	 * {@code null} when the response is already committed
 	 */
-	protected @Nullable ResponseEntity<Object> handleExceptionInternal(
+	protected @Nullable ResponseEntity<@Nullable Object> handleExceptionInternal(
 			Exception ex, @Nullable Object body, HttpHeaders headers, HttpStatusCode statusCode, WebRequest request) {
 
 		if (request instanceof ServletWebRequest servletWebRequest) {
@@ -650,10 +650,10 @@ public abstract class ResponseEntityExceptionHandler implements MessageSourceAwa
 	 * @return the {@code ResponseEntity} instance to use
 	 * @since 6.0
 	 */
-	protected ResponseEntity<Object> createResponseEntity(
+	protected ResponseEntity<@Nullable Object> createResponseEntity(
 			@Nullable Object body, HttpHeaders headers, HttpStatusCode statusCode, WebRequest request) {
 
-		return new ResponseEntity<>(body, headers, statusCode);
+		return new ResponseEntity<@Nullable Object>(body, headers, statusCode);
 	}
 
 }