Tests for ErrorResponse hierarchy to verify the output

See gh-27052

spring-web/src/main/java/org/springframework/web/ErrorResponseException.java

@@ -61,7 +61,7 @@ public class ErrorResponseException extends NestedRuntimeException implements Er
 	 * Constructor with a well-known {@link HttpStatus} and an optional cause.
 	 */
 	public ErrorResponseException(HttpStatus status, @Nullable Throwable cause) {
-		this(status.value(), null);
+		this(status.value(), cause);
 	}
 
 	/**

spring-web/src/main/java/org/springframework/web/HttpMediaTypeNotAcceptableException.java

@@ -17,6 +17,7 @@
 package org.springframework.web;
 
 import java.util.List;
+import java.util.stream.Collectors;
 
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpStatus;
@@ -39,15 +40,17 @@ public class HttpMediaTypeNotAcceptableException extends HttpMediaTypeException
 	 */
 	public HttpMediaTypeNotAcceptableException(String message) {
 		super(message);
-		getBody().setDetail("Could not parse Accept header");
+		getBody().setDetail("Could not parse Accept header.");
 	}
 
 	/**
 	 * Create a new HttpMediaTypeNotSupportedException.
-	 * @param supportedMediaTypes the list of supported media types
+	 * @param mediaTypes the list of supported media types
 	 */
-	public HttpMediaTypeNotAcceptableException(List<MediaType> supportedMediaTypes) {
-		super("No acceptable representation", supportedMediaTypes);
+	public HttpMediaTypeNotAcceptableException(List<MediaType> mediaTypes) {
+		super("No acceptable representation", mediaTypes);
+		getBody().setDetail("Acceptable representations: " +
+				mediaTypes.stream().map(MediaType::toString).collect(Collectors.joining(", ", "'", "'")) + ".");
 	}
 
 

spring-web/src/main/java/org/springframework/web/HttpMediaTypeNotSupportedException.java

@@ -51,29 +51,29 @@ public class HttpMediaTypeNotSupportedException extends HttpMediaTypeException {
 		super(message);
 		this.contentType = null;
 		this.httpMethod = null;
-		getBody().setDetail("Could not parse Content-Type");
+		getBody().setDetail("Could not parse Content-Type.");
 	}
 
 	/**
 	 * Create a new HttpMediaTypeNotSupportedException.
 	 * @param contentType the unsupported content type
-	 * @param supportedMediaTypes the list of supported media types
+	 * @param mediaTypes the list of supported media types
 	 */
-	public HttpMediaTypeNotSupportedException(@Nullable MediaType contentType, List<MediaType> supportedMediaTypes) {
-		this(contentType, supportedMediaTypes, null);
+	public HttpMediaTypeNotSupportedException(@Nullable MediaType contentType, List<MediaType> mediaTypes) {
+		this(contentType, mediaTypes, null);
 	}
 
 	/**
 	 * Create a new HttpMediaTypeNotSupportedException.
 	 * @param contentType the unsupported content type
-	 * @param supportedMediaTypes the list of supported media types
+	 * @param mediaTypes the list of supported media types
 	 * @param httpMethod the HTTP method of the request
 	 * @since 6.0
 	 */
-	public HttpMediaTypeNotSupportedException(@Nullable MediaType contentType,
-			List<MediaType> supportedMediaTypes, @Nullable HttpMethod httpMethod) {
+	public HttpMediaTypeNotSupportedException(
+			@Nullable MediaType contentType, List<MediaType> mediaTypes, @Nullable HttpMethod httpMethod) {
 
-		this(contentType, supportedMediaTypes, httpMethod,
+		this(contentType, mediaTypes, httpMethod,
 				"Content-Type " + (contentType != null ? "'" + contentType + "' " : "") + "is not supported");
 	}
 
@@ -91,7 +91,7 @@ public class HttpMediaTypeNotSupportedException extends HttpMediaTypeException {
 		super(message, supportedMediaTypes);
 		this.contentType = contentType;
 		this.httpMethod = httpMethod;
-		getBody().setDetail("Content-Type " + this.contentType + " is not supported");
+		getBody().setDetail("Content-Type '" + this.contentType + "' is not supported.");
 	}
 
 

spring-web/src/main/java/org/springframework/web/HttpRequestMethodNotSupportedException.java

@@ -93,8 +93,9 @@ public class HttpRequestMethodNotSupportedException extends ServletException imp
 		super(msg);
 		this.method = method;
 		this.supportedMethods = supportedMethods;
-		this.body = ProblemDetail.forRawStatusCode(getRawStatusCode())
-				.withDetail("Method '" + method + "' is not supported");
+
+		String detail = "Method '" + method + "' is not supported.";
+		this.body = ProblemDetail.forRawStatusCode(getRawStatusCode()).withDetail(detail);
 	}
 
 

spring-web/src/main/java/org/springframework/web/bind/MethodArgumentNotValidException.java

@@ -48,7 +48,7 @@ public class MethodArgumentNotValidException extends BindException implements Er
 	public MethodArgumentNotValidException(MethodParameter parameter, BindingResult bindingResult) {
 		super(bindingResult);
 		this.parameter = parameter;
-		this.body = ProblemDetail.forRawStatusCode(getRawStatusCode()).withDetail(initMessage(parameter));
+		this.body = ProblemDetail.forRawStatusCode(getRawStatusCode()).withDetail("Invalid request content.");
 	}
 
 
@@ -71,13 +71,9 @@ public class MethodArgumentNotValidException extends BindException implements Er
 
 	@Override
 	public String getMessage() {
-		return initMessage(this.parameter);
-	}
-
-	private String initMessage(MethodParameter parameter) {
 		StringBuilder sb = new StringBuilder("Validation failed for argument [")
-				.append(parameter.getParameterIndex()).append("] in ")
-				.append(parameter.getExecutable().toGenericString());
+				.append(this.parameter.getParameterIndex()).append("] in ")
+				.append(this.parameter.getExecutable().toGenericString());
 		BindingResult bindingResult = getBindingResult();
 		if (bindingResult.getErrorCount() > 1) {
 			sb.append(" with ").append(bindingResult.getErrorCount()).append(" errors");

spring-web/src/main/java/org/springframework/web/bind/MissingMatrixVariableException.java

@@ -57,7 +57,7 @@ public class MissingMatrixVariableException extends MissingRequestValueException
 		super("", missingAfterConversion);
 		this.variableName = variableName;
 		this.parameter = parameter;
-		getBody().setDetail("Required path parameter '" + this.variableName + "' is not present");
+		getBody().setDetail("Required path parameter '" + this.variableName + "' is not present.");
 	}
 
 

spring-web/src/main/java/org/springframework/web/bind/MissingPathVariableException.java

@@ -60,7 +60,7 @@ public class MissingPathVariableException extends MissingRequestValueException {
 		super("", missingAfterConversion);
 		this.variableName = variableName;
 		this.parameter = parameter;
-		getBody().setDetail("Required URI variable '" + this.variableName + "' is not present");
+		getBody().setDetail("Required path variable '" + this.variableName + "' is not present.");
 	}
 
 

spring-web/src/main/java/org/springframework/web/bind/MissingRequestCookieException.java

@@ -57,7 +57,7 @@ public class MissingRequestCookieException extends MissingRequestValueException
 		super("", missingAfterConversion);
 		this.cookieName = cookieName;
 		this.parameter = parameter;
-		getBody().setDetail("Required cookie '" + this.cookieName + "' is not present");
+		getBody().setDetail("Required cookie '" + this.cookieName + "' is not present.");
 	}
 
 

spring-web/src/main/java/org/springframework/web/bind/MissingRequestHeaderException.java

@@ -57,7 +57,7 @@ public class MissingRequestHeaderException extends MissingRequestValueException
 		super("", missingAfterConversion);
 		this.headerName = headerName;
 		this.parameter = parameter;
-		getBody().setDetail("Required header '" + this.headerName + "' is not present");
+		getBody().setDetail("Required header '" + this.headerName + "' is not present.");
 	}
 
 

spring-web/src/main/java/org/springframework/web/bind/MissingServletRequestParameterException.java

@@ -52,7 +52,7 @@ public class MissingServletRequestParameterException extends MissingRequestValue
 		super("", missingAfterConversion);
 		this.parameterName = parameterName;
 		this.parameterType = parameterType;
-		getBody().setDetail("Required parameter '" + this.parameterName + "' is not present");
+		getBody().setDetail("Required parameter '" + this.parameterName + "' is not present.");
 	}
 
 

spring-web/src/main/java/org/springframework/web/bind/UnsatisfiedServletRequestParameterException.java

@@ -16,7 +16,6 @@
 
 package org.springframework.web.bind;
 
-import java.util.Arrays;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
@@ -48,9 +47,7 @@ public class UnsatisfiedServletRequestParameterException extends ServletRequestB
 	 * @param actualParams the actual parameter Map associated with the ServletRequest
 	 */
 	public UnsatisfiedServletRequestParameterException(String[] paramConditions, Map<String, String[]> actualParams) {
-		super("");
-		this.paramConditions = Arrays.<String[]>asList(paramConditions);
-		this.actualParams = actualParams;
+		this(List.<String[]>of(paramConditions), actualParams);
 	}
 
 	/**
@@ -66,6 +63,7 @@ public class UnsatisfiedServletRequestParameterException extends ServletRequestB
 		Assert.notEmpty(paramConditions, "Parameter conditions must not be empty");
 		this.paramConditions = paramConditions;
 		this.actualParams = actualParams;
+		getBody().setDetail("Invalid request parameters.");
 	}
 
 

spring-web/src/main/java/org/springframework/web/bind/support/WebExchangeBindException.java

@@ -49,6 +49,7 @@ public class WebExchangeBindException extends ServerWebInputException implements
 	public WebExchangeBindException(MethodParameter parameter, BindingResult bindingResult) {
 		super("Validation failure", parameter);
 		this.bindingResult = bindingResult;
+		getBody().setDetail("Invalid request content.");
 	}
 
 

spring-web/src/main/java/org/springframework/web/multipart/support/MissingServletRequestPartException.java

@@ -40,7 +40,7 @@ public class MissingServletRequestPartException extends ServletRequestBindingExc
 	 * @param requestPartName the name of the missing part of the multipart request
 	 */
 	public MissingServletRequestPartException(String requestPartName) {
-		super("Required request part '" + requestPartName + "' is not present");
+		super("Required part '" + requestPartName + "' is not present.");
 		this.requestPartName = requestPartName;
 		getBody().setDetail(getMessage());
 	}

spring-web/src/main/java/org/springframework/web/server/MethodNotAllowedException.java

@@ -20,6 +20,7 @@ import java.util.Collection;
 import java.util.Collections;
 import java.util.LinkedHashSet;
 import java.util.Set;
+import java.util.stream.Collectors;
 
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpMethod;
@@ -47,13 +48,17 @@ public class MethodNotAllowedException extends ResponseStatusException {
 	}
 
 	public MethodNotAllowedException(String method, @Nullable Collection<HttpMethod> supportedMethods) {
-		super(HttpStatus.METHOD_NOT_ALLOWED, "Request method '" + method + "' not supported");
+		super(HttpStatus.METHOD_NOT_ALLOWED, "Request method '" + method + "' is not supported.");
 		Assert.notNull(method, "'method' is required");
 		if (supportedMethods == null) {
 			supportedMethods = Collections.emptySet();
 		}
 		this.method = method;
 		this.httpMethods = Collections.unmodifiableSet(new LinkedHashSet<>(supportedMethods));
+
+		getBody().setDetail(this.httpMethods.isEmpty() ? getReason() :
+				"Supported methods: " + this.httpMethods.stream()
+						.map(HttpMethod::toString).collect(Collectors.joining("', '", "'", "'")));
 	}
 
 

spring-web/src/main/java/org/springframework/web/server/NotAcceptableStatusException.java

@@ -18,6 +18,7 @@ package org.springframework.web.server;
 
 import java.util.Collections;
 import java.util.List;
+import java.util.stream.Collectors;
 
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpStatus;
@@ -42,14 +43,17 @@ public class NotAcceptableStatusException extends ResponseStatusException {
 	public NotAcceptableStatusException(String reason) {
 		super(HttpStatus.NOT_ACCEPTABLE, reason);
 		this.supportedMediaTypes = Collections.emptyList();
+		getBody().setDetail("Could not parse Accept header.");
 	}
 
 	/**
 	 * Constructor for when the requested Content-Type is not supported.
 	 */
-	public NotAcceptableStatusException(List<MediaType> supportedMediaTypes) {
+	public NotAcceptableStatusException(List<MediaType> mediaTypes) {
 		super(HttpStatus.NOT_ACCEPTABLE, "Could not find acceptable representation");
-		this.supportedMediaTypes = Collections.unmodifiableList(supportedMediaTypes);
+		this.supportedMediaTypes = Collections.unmodifiableList(mediaTypes);
+		getBody().setDetail("Acceptable representations: " +
+				mediaTypes.stream().map(MediaType::toString).collect(Collectors.joining(", ", "'", "'")) + ".");
 	}
 
 

spring-web/src/main/java/org/springframework/web/server/ResponseStatusException.java

@@ -77,7 +77,6 @@ public class ResponseStatusException extends ErrorResponseException {
 	public ResponseStatusException(int rawStatusCode, @Nullable String reason, @Nullable Throwable cause) {
 		super(rawStatusCode, cause);
 		this.reason = reason;
-		setDetail(reason);
 	}
 
 

spring-web/src/main/java/org/springframework/web/server/UnsupportedMediaTypeStatusException.java

@@ -57,6 +57,7 @@ public class UnsupportedMediaTypeStatusException extends ResponseStatusException
 		this.supportedMediaTypes = Collections.emptyList();
 		this.bodyType = null;
 		this.method = null;
+		getBody().setDetail("Could not parse Content-Type.");
 	}
 
 	/**
@@ -100,8 +101,7 @@ public class UnsupportedMediaTypeStatusException extends ResponseStatusException
 		this.bodyType = bodyType;
 		this.method = method;
 
-		// Set explicitly to avoid implementation details
-		setDetail(contentType != null ? "Content-Type '" + contentType + "' is not supported" : null);
+		setDetail(contentType != null ? "Content-Type '" + contentType + "' is not supported." : null);
 	}
 
 

spring-web/src/test/java/org/springframework/web/ErrorResponseExceptionTests.java

@@ -0,0 +1,349 @@
+/*
+ * 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.web;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.core.MethodParameter;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
+import org.springframework.http.ProblemDetail;
+import org.springframework.lang.Nullable;
+import org.springframework.validation.BindException;
+import org.springframework.validation.BindingResult;
+import org.springframework.validation.FieldError;
+import org.springframework.web.bind.MethodArgumentNotValidException;
+import org.springframework.web.bind.MissingMatrixVariableException;
+import org.springframework.web.bind.MissingPathVariableException;
+import org.springframework.web.bind.MissingRequestCookieException;
+import org.springframework.web.bind.MissingRequestHeaderException;
+import org.springframework.web.bind.MissingServletRequestParameterException;
+import org.springframework.web.bind.UnsatisfiedServletRequestParameterException;
+import org.springframework.web.bind.support.WebExchangeBindException;
+import org.springframework.web.context.request.async.AsyncRequestTimeoutException;
+import org.springframework.web.multipart.support.MissingServletRequestPartException;
+import org.springframework.web.server.MethodNotAllowedException;
+import org.springframework.web.server.NotAcceptableStatusException;
+import org.springframework.web.server.UnsupportedMediaTypeStatusException;
+import org.springframework.web.testfixture.method.ResolvableMethod;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+
+/**
+ * Unit tests that verify the HTTP response details exposed by exceptions in the
+ * {@link ErrorResponse} hierarchy.
+ *
+ * @author Rossen Stoyanchev
+ */
+public class ErrorResponseExceptionTests {
+
+	private final MethodParameter methodParameter =
+			new MethodParameter(ResolvableMethod.on(getClass()).resolveMethod("handle"), 0);
+
+
+	@Test
+	void httpMediaTypeNotSupportedException() {
+
+		List<MediaType> mediaTypes =
+				Arrays.asList(MediaType.APPLICATION_JSON, MediaType.APPLICATION_CBOR);
+
+		ErrorResponse ex = new HttpMediaTypeNotSupportedException(
+				MediaType.APPLICATION_XML, mediaTypes, HttpMethod.PATCH, "Custom message");
+
+
+		assertStatus(ex, HttpStatus.UNSUPPORTED_MEDIA_TYPE);
+		assertDetail(ex, "Content-Type 'application/xml' is not supported.");
+
+		HttpHeaders headers = ex.getHeaders();
+		assertThat(headers.getAccept()).isEqualTo(mediaTypes);
+		assertThat(headers.getAcceptPatch()).isEqualTo(mediaTypes);
+	}
+
+	@Test
+	void httpMediaTypeNotSupportedExceptionWithParseError() {
+
+		ErrorResponse ex = new HttpMediaTypeNotSupportedException(
+				"Could not parse Accept header: Invalid mime type \"foo\": does not contain '/'");
+
+
+		assertStatus(ex, HttpStatus.UNSUPPORTED_MEDIA_TYPE);
+		assertDetail(ex, "Could not parse Content-Type.");
+		assertThat(ex.getHeaders()).isEmpty();
+	}
+
+	@Test
+	void httpMediaTypeNotAcceptableException() {
+
+		List<MediaType> mediaTypes = Arrays.asList(MediaType.APPLICATION_JSON, MediaType.APPLICATION_CBOR);
+		ErrorResponse ex = new HttpMediaTypeNotAcceptableException(mediaTypes);
+
+
+		assertStatus(ex, HttpStatus.NOT_ACCEPTABLE);
+		assertDetail(ex, "Acceptable representations: 'application/json, application/cbor'.");
+
+		assertThat(ex.getHeaders()).hasSize(1);
+		assertThat(ex.getHeaders().getAccept()).isEqualTo(mediaTypes);
+	}
+
+	@Test
+	void httpMediaTypeNotAcceptableExceptionWithParseError() {
+
+		ErrorResponse ex = new HttpMediaTypeNotAcceptableException(
+				"Could not parse Accept header: Invalid mime type \"foo\": does not contain '/'");
+
+
+		assertStatus(ex, HttpStatus.NOT_ACCEPTABLE);
+		assertDetail(ex, "Could not parse Accept header.");
+		assertThat(ex.getHeaders()).isEmpty();
+	}
+
+	@Test
+	void asyncRequestTimeoutException() {
+
+		ErrorResponse ex = new AsyncRequestTimeoutException();
+
+
+		assertStatus(ex, HttpStatus.SERVICE_UNAVAILABLE);
+		assertDetail(ex, null);
+		assertThat(ex.getHeaders()).isEmpty();
+	}
+
+	@Test
+	void httpRequestMethodNotSupportedException() {
+
+		String[] supportedMethods = new String[] { "GET", "POST" };
+		ErrorResponse ex = new HttpRequestMethodNotSupportedException("PUT", supportedMethods, "Custom message");
+
+
+		assertStatus(ex, HttpStatus.METHOD_NOT_ALLOWED);
+		assertDetail(ex, "Method 'PUT' is not supported.");
+
+		assertThat(ex.getHeaders()).hasSize(1);
+		assertThat(ex.getHeaders().getAllow()).containsExactly(HttpMethod.GET, HttpMethod.POST);
+	}
+
+	@Test
+	void missingRequestHeaderException() {
+
+		ErrorResponse ex = new MissingRequestHeaderException("Authorization", this.methodParameter);
+
+
+		assertStatus(ex, HttpStatus.BAD_REQUEST);
+		assertDetail(ex, "Required header 'Authorization' is not present.");
+		assertThat(ex.getHeaders()).isEmpty();
+	}
+
+	@Test
+	void missingServletRequestParameterException() {
+
+		ErrorResponse ex = new MissingServletRequestParameterException("query", "String");
+
+
+		assertStatus(ex, HttpStatus.BAD_REQUEST);
+		assertDetail(ex, "Required parameter 'query' is not present.");
+		assertThat(ex.getHeaders()).isEmpty();
+	}
+
+	@Test
+	void missingMatrixVariableException() {
+
+		ErrorResponse ex = new MissingMatrixVariableException("region", this.methodParameter);
+
+
+		assertStatus(ex, HttpStatus.BAD_REQUEST);
+		assertDetail(ex, "Required path parameter 'region' is not present.");
+		assertThat(ex.getHeaders()).isEmpty();
+	}
+
+	@Test
+	void missingPathVariableException() {
+
+		ErrorResponse ex = new MissingPathVariableException("id", this.methodParameter);
+
+
+		assertStatus(ex, HttpStatus.INTERNAL_SERVER_ERROR);
+		assertDetail(ex, "Required path variable 'id' is not present.");
+		assertThat(ex.getHeaders()).isEmpty();
+	}
+
+	@Test
+	void missingRequestCookieException() {
+
+		ErrorResponse ex = new MissingRequestCookieException("oreo", this.methodParameter);
+
+
+		assertStatus(ex, HttpStatus.BAD_REQUEST);
+		assertDetail(ex, "Required cookie 'oreo' is not present.");
+		assertThat(ex.getHeaders()).isEmpty();
+	}
+
+	@Test
+	void unsatisfiedServletRequestParameterException() {
+
+		ErrorResponse ex = new UnsatisfiedServletRequestParameterException(
+				new String[] { "foo=bar", "bar=baz" }, Collections.singletonMap("q", new String[] {"1"}));
+
+
+		assertStatus(ex, HttpStatus.BAD_REQUEST);
+		assertDetail(ex, "Invalid request parameters.");
+		assertThat(ex.getHeaders()).isEmpty();
+	}
+
+	@Test
+	void missingServletRequestPartException() {
+
+		ErrorResponse ex = new MissingServletRequestPartException("file");
+
+		assertStatus(ex, HttpStatus.BAD_REQUEST);
+		assertDetail(ex, "Required part 'file' is not present.");
+		assertThat(ex.getHeaders()).isEmpty();
+	}
+
+	@Test
+	void methodArgumentNotValidException() {
+
+		BindingResult bindingResult = new BindException(new Object(), "object");
+		bindingResult.addError(new FieldError("object", "field", "message"));
+
+		ErrorResponse ex = new MethodArgumentNotValidException(this.methodParameter, bindingResult);
+
+		assertStatus(ex, HttpStatus.BAD_REQUEST);
+		assertDetail(ex, "Invalid request content.");
+		assertThat(ex.getHeaders()).isEmpty();
+	}
+
+	@Test
+	void unsupportedMediaTypeStatusException() {
+
+		List<MediaType> mediaTypes =
+				Arrays.asList(MediaType.APPLICATION_JSON, MediaType.APPLICATION_CBOR);
+
+		ErrorResponse ex = new UnsupportedMediaTypeStatusException(
+				MediaType.APPLICATION_XML, mediaTypes, HttpMethod.PATCH);
+
+		assertStatus(ex, HttpStatus.UNSUPPORTED_MEDIA_TYPE);
+		assertDetail(ex, "Content-Type 'application/xml' is not supported.");
+
+		HttpHeaders headers = ex.getHeaders();
+		assertThat(headers.getAccept()).isEqualTo(mediaTypes);
+		assertThat(headers.getAcceptPatch()).isEqualTo(mediaTypes);
+	}
+
+	@Test
+	void unsupportedMediaTypeStatusExceptionWithParseError() {
+
+		ErrorResponse ex = new UnsupportedMediaTypeStatusException(
+				"Could not parse Accept header: Invalid mime type \"foo\": does not contain '/'");
+
+		assertStatus(ex, HttpStatus.UNSUPPORTED_MEDIA_TYPE);
+		assertDetail(ex, "Could not parse Content-Type.");
+		assertThat(ex.getHeaders()).isEmpty();
+	}
+
+	@Test
+	void notAcceptableStatusException() {
+
+		List<MediaType> mediaTypes =
+				Arrays.asList(MediaType.APPLICATION_JSON, MediaType.APPLICATION_CBOR);
+
+		ErrorResponse ex = new NotAcceptableStatusException(mediaTypes);
+
+		assertStatus(ex, HttpStatus.NOT_ACCEPTABLE);
+		assertDetail(ex, "Acceptable representations: 'application/json, application/cbor'.");
+
+		assertThat(ex.getHeaders()).hasSize(1);
+		assertThat(ex.getHeaders().getAccept()).isEqualTo(mediaTypes);
+	}
+
+	@Test
+	void notAcceptableStatusExceptionWithParseError() {
+
+		ErrorResponse ex = new NotAcceptableStatusException(
+				"Could not parse Accept header: Invalid mime type \"foo\": does not contain '/'");
+
+
+		assertStatus(ex, HttpStatus.NOT_ACCEPTABLE);
+		assertDetail(ex, "Could not parse Accept header.");
+		assertThat(ex.getHeaders()).isEmpty();
+	}
+
+	@Test
+	void webExchangeBindException() {
+
+		BindingResult bindingResult = new BindException(new Object(), "object");
+		bindingResult.addError(new FieldError("object", "field", "message"));
+
+		ErrorResponse ex = new WebExchangeBindException(this.methodParameter, bindingResult);
+
+		assertStatus(ex, HttpStatus.BAD_REQUEST);
+		assertDetail(ex, "Invalid request content.");
+		assertThat(ex.getHeaders()).isEmpty();
+	}
+
+	@Test
+	void methodNotAllowedException() {
+
+		List<HttpMethod> supportedMethods = Arrays.asList(HttpMethod.GET, HttpMethod.POST);
+		ErrorResponse ex = new MethodNotAllowedException(HttpMethod.PUT, supportedMethods);
+
+
+		assertStatus(ex, HttpStatus.METHOD_NOT_ALLOWED);
+		assertDetail(ex, "Supported methods: 'GET', 'POST'");
+
+		assertThat(ex.getHeaders()).hasSize(1);
+		assertThat(ex.getHeaders().getAllow()).containsExactly(HttpMethod.GET, HttpMethod.POST);
+	}
+
+	@Test
+	void methodNotAllowedExceptionWithoutSupportedMethods() {
+
+		ErrorResponse ex = new MethodNotAllowedException(HttpMethod.PUT, Collections.emptyList());
+
+
+		assertStatus(ex, HttpStatus.METHOD_NOT_ALLOWED);
+		assertDetail(ex, "Request method 'PUT' is not supported.");
+		assertThat(ex.getHeaders()).isEmpty();
+	}
+
+	private void assertStatus(ErrorResponse ex, HttpStatus status) {
+		ProblemDetail body = ex.getBody();
+		assertThat(ex.getStatus()).isEqualTo(status);
+		assertThat(body.getStatus()).isEqualTo(status.value());
+		assertThat(body.getTitle()).isEqualTo(status.getReasonPhrase());
+	}
+
+	private void assertDetail(ErrorResponse ex, @Nullable String detail) {
+		if (detail != null) {
+			assertThat(ex.getBody().getDetail()).isEqualTo(detail);
+		}
+		else {
+			assertThat(ex.getBody().getDetail()).isNull();
+		}
+	}
+
+
+	@SuppressWarnings("unused")
+	private void handle(String arg) {}
+
+}

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

@@ -45,7 +45,7 @@ public class NoHandlerFoundException extends ServletException implements ErrorRe
 
 	private final HttpHeaders headers;
 
-	private final ProblemDetail detail = ProblemDetail.forRawStatusCode(getRawStatusCode());
+	private final ProblemDetail body;
 
 
 	/**
@@ -55,10 +55,11 @@ public class NoHandlerFoundException extends ServletException implements ErrorRe
 	 * @param headers the HTTP request headers
 	 */
 	public NoHandlerFoundException(String httpMethod, String requestURL, HttpHeaders headers) {
-		super("No handler found for " + httpMethod + " " + requestURL);
+		super("No endpoint " + httpMethod + " " + requestURL + ".");
 		this.httpMethod = httpMethod;
 		this.requestURL = requestURL;
 		this.headers = headers;
+		this.body = ProblemDetail.forRawStatusCode(getRawStatusCode()).withDetail(getMessage());
 	}
 
 
@@ -81,7 +82,7 @@ public class NoHandlerFoundException extends ServletException implements ErrorRe
 
 	@Override
 	public ProblemDetail getBody() {
-		return this.detail;
+		return this.body;
 	}
 
 }

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

@@ -154,6 +154,7 @@ public abstract class ResponseEntityExceptionHandler {
 				return handleAsyncRequestTimeoutException(subEx, subEx.getHeaders(), subEx.getStatus(), request);
 			}
 			else {
+				// Another ErrorResponseException
 				return handleExceptionInternal(ex, null, errorEx.getHeaders(), errorEx.getStatus(), request);
 			}
 		}