Polishing and minor refactoring

Closes gh-31202

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

@@ -88,14 +88,6 @@ public sealed interface HttpStatusCode extends Serializable permits DefaultHttpS
 		return value() == other.value();
 	}
 
-	/**
-	 * Checks whether this status code is a well-known HTTP status code or not
-	 * @return {@code true} if the status code corresponds to a standard HTTP status code, {@code false} otherwise
-	 */
-	default boolean isWellKnown() {
-		return HttpStatus.resolve(this.value()) != null;
-	}
-
 	/**
 	 * Return an {@code HttpStatusCode} object for the given integer value.
 	 * @param code the status code as integer

spring-webflux/src/main/java/org/springframework/web/reactive/function/client/DefaultWebClient.java

@@ -515,12 +515,9 @@ final class DefaultWebClient implements WebClient {
 
 	private static class DefaultResponseSpec implements ResponseSpec {
 
-		private static final Predicate<HttpStatusCode> STATUS_CODE_ERROR = HttpStatusCode::isError;
-		private static final Predicate<HttpStatusCode> STATUS_CODE_UNKNOWN = status -> !status.isWellKnown();
-		private static final StatusHandler DEFAULT_ERROR_STATUS_HANDLER =
-				new StatusHandler(STATUS_CODE_ERROR, ClientResponse::createException);
-		private static final StatusHandler DEFAULT_UNKNOWN_STATUS_HANDLER =
-				new StatusHandler(STATUS_CODE_UNKNOWN, ClientResponse::createException);
+		private static final StatusHandler DEFAULT_STATUS_HANDLER =
+				new StatusHandler(code -> code.value() >= 400, ClientResponse::createException);
+
 
 		private final HttpMethod httpMethod;
 
@@ -539,8 +536,7 @@ final class DefaultWebClient implements WebClient {
 			this.uri = uri;
 			this.responseMono = responseMono;
 			this.statusHandlers.addAll(defaultStatusHandlers);
-			this.statusHandlers.add(DEFAULT_ERROR_STATUS_HANDLER);
-			this.statusHandlers.add(DEFAULT_UNKNOWN_STATUS_HANDLER);
+			this.statusHandlers.add(DEFAULT_STATUS_HANDLER);
 			this.defaultStatusHandlerCount = this.statusHandlers.size();
 		}
 

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

@@ -644,14 +644,14 @@ class WebClientIntegrationTests {
 
 		int errorStatus = 555;
 		assertThat(HttpStatus.resolve(errorStatus)).isNull();
+
 		String errorMessage = "Something went wrong";
-		prepareResponse(response -> response.setResponseCode(errorStatus)
-				.setHeader("Content-Type", "text/plain").setBody(errorMessage));
+		prepareResponse(response ->
+				response.setResponseCode(errorStatus)
+						.setHeader("Content-Type", "text/plain")
+						.setBody(errorMessage));
 
-		Mono<String> result = this.webClient.get()
-				.uri("/unknownPage")
-				.retrieve()
-				.bodyToMono(String.class);
+		Mono<String> result = this.webClient.get().uri("/unknownPage").retrieve().bodyToMono(String.class);
 
 		StepVerifier.create(result)
 				.expectErrorSatisfies(throwable -> {
@@ -672,20 +672,20 @@ class WebClientIntegrationTests {
 		});
 	}
 
-	@ParameterizedWebClientTest
-	void retrieve929CustomUnknownStatus(ClientHttpConnector connector) {
+	@ParameterizedWebClientTest // gh-31202
+	void retrieve929UnknownStatusCode(ClientHttpConnector connector) {
 		startServer(connector);
 
 		int errorStatus = 929;
 		assertThat(HttpStatus.resolve(errorStatus)).isNull();
+
 		String errorMessage = "Something went wrong";
-		prepareResponse(response -> response.setResponseCode(errorStatus)
-				.setHeader("Content-Type", "text/plain").setBody(errorMessage));
+		prepareResponse(response ->
+				response.setResponseCode(errorStatus)
+						.setHeader("Content-Type", "text/plain")
+						.setBody(errorMessage));
 
-		Mono<String> result = this.webClient.get()
-				.uri("/unknownPage")
-				.retrieve()
-				.bodyToMono(String.class);
+		Mono<String> result = this.webClient.get().uri("/unknownPage").retrieve().bodyToMono(String.class);
 
 		StepVerifier.create(result)
 				.expectErrorSatisfies(throwable -> {