Add runtime hints for WebFlux

Closes gh-28701

spring-web/src/main/java/org/springframework/http/codec/CodecConfigurerHintsRegistrar.java

@@ -0,0 +1,46 @@
+/*
+ * 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.http.codec;
+
+import org.springframework.aot.hint.MemberCategory;
+import org.springframework.aot.hint.RuntimeHints;
+import org.springframework.aot.hint.RuntimeHintsRegistrar;
+import org.springframework.aot.hint.TypeReference;
+import org.springframework.http.codec.support.DefaultClientCodecConfigurer;
+import org.springframework.http.codec.support.DefaultServerCodecConfigurer;
+import org.springframework.lang.Nullable;
+
+/**
+ * {@link RuntimeHintsRegistrar} implementation that registers runtime hints for
+ * implementations listed in {@code CodecConfigurer.properties}.
+ *
+ * @author Sebastien Deleuze
+ * @since 6.0
+ */
+public class CodecConfigurerHintsRegistrar implements RuntimeHintsRegistrar {
+
+	@Override
+	public void registerHints(RuntimeHints hints, @Nullable ClassLoader classLoader) {
+		hints.resources().registerPattern("org/springframework/http/codec/CodecConfigurer.properties");
+		hints.reflection().registerType(DefaultClientCodecConfigurer.class, builder ->
+				builder.onReachableType(TypeReference.of(CodecConfigurerFactory.class))
+						.withMembers(MemberCategory.INVOKE_PUBLIC_CONSTRUCTORS));
+		hints.reflection().registerType(DefaultServerCodecConfigurer.class, builder ->
+				builder.onReachableType(TypeReference.of(CodecConfigurerFactory.class))
+						.withMembers(MemberCategory.INVOKE_PUBLIC_CONSTRUCTORS));
+	}
+}

spring-web/src/main/resources/META-INF/spring/aot.factories

@@ -1,2 +1,3 @@
 org.springframework.aot.hint.RuntimeHintsRegistrar= \
-org.springframework.http.MediaTypeResourceHintsRegistrar
+org.springframework.http.MediaTypeResourceHintsRegistrar,\
+org.springframework.http.codec.CodecConfigurerHintsRegistrar

spring-webflux/src/main/java/org/springframework/web/reactive/config/WebFluxConfigurationSupport.java

@@ -28,6 +28,7 @@ import org.springframework.beans.factory.annotation.Qualifier;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.ApplicationContextAware;
 import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.ImportRuntimeHints;
 import org.springframework.core.ReactiveAdapterRegistry;
 import org.springframework.core.annotation.Order;
 import org.springframework.core.convert.converter.Converter;
@@ -45,6 +46,7 @@ import org.springframework.validation.Errors;
 import org.springframework.validation.MessageCodesResolver;
 import org.springframework.validation.Validator;
 import org.springframework.web.bind.WebDataBinder;
+import org.springframework.web.bind.annotation.WebAnnotationsRuntimeHintsRegistrar;
 import org.springframework.web.bind.support.ConfigurableWebBindingInitializer;
 import org.springframework.web.cors.CorsConfiguration;
 import org.springframework.web.reactive.DispatcherHandler;
@@ -83,6 +85,7 @@ import org.springframework.web.server.i18n.LocaleContextResolver;
  * @author Brian Clozel
  * @since 5.0
  */
+@ImportRuntimeHints(WebAnnotationsRuntimeHintsRegistrar.class)
 public class WebFluxConfigurationSupport implements ApplicationContextAware {
 
 	@Nullable