Use bean class loader when creating interface clients

Update interface client code to replace `GroupsMetadata.loadClass` calls
with `ClassUtils.resolveClassName` passing in the bean class loader.

Since the bean class loader in injected after construction, some minor
refactoring has been applied to `HttpServiceProxyRegistryFactoryBean`.
The class now stores `GroupsMetadata` and only loads the types in
in `afterPropertiesSet`.

The `HttpServiceProxyFactory` class has also been updated to ensure
that the proxy is created using the class loader of the service
type, rather than the thread context class loader.

Fixes gh-34846

spring-web/src/main/java/org/springframework/web/service/invoker/HttpServiceProxyFactory.java

@@ -89,7 +89,14 @@ public final class HttpServiceProxyFactory {
 						.map(method -> createHttpServiceMethod(serviceType, method))
 						.toList();
 
-		return ProxyFactory.getProxy(serviceType, new HttpServiceMethodInterceptor(httpServiceMethods));
+		return getProxy(serviceType, httpServiceMethods);
+	}
+
+	@SuppressWarnings("unchecked")
+	private <S> S getProxy(Class<S> serviceType, List<HttpServiceMethod> httpServiceMethods) {
+		MethodInterceptor interceptor = new HttpServiceMethodInterceptor(httpServiceMethods);
+		ProxyFactory proxyFactory = new ProxyFactory(serviceType, interceptor);
+		return (S) proxyFactory.getProxy(serviceType.getClassLoader());
 	}
 
 	private boolean isExchangeMethod(Method method) {

spring-web/src/main/java/org/springframework/web/service/registry/AbstractHttpServiceRegistrar.java

@@ -19,6 +19,7 @@ package org.springframework.web.service.registry;
 import org.jspecify.annotations.Nullable;
 
 import org.springframework.beans.BeansException;
+import org.springframework.beans.factory.BeanClassLoaderAware;
 import org.springframework.beans.factory.BeanFactory;
 import org.springframework.beans.factory.BeanFactoryAware;
 import org.springframework.beans.factory.annotation.AnnotatedBeanDefinition;
@@ -38,6 +39,7 @@ import org.springframework.core.type.MethodMetadata;
 import org.springframework.core.type.classreading.MetadataReader;
 import org.springframework.core.type.filter.AnnotationTypeFilter;
 import org.springframework.util.Assert;
+import org.springframework.util.ClassUtils;
 import org.springframework.web.service.annotation.HttpExchange;
 
 /**
@@ -74,7 +76,7 @@ import org.springframework.web.service.annotation.HttpExchange;
  * @see HttpServiceProxyRegistryFactoryBean
  */
 public abstract class AbstractHttpServiceRegistrar implements
-		ImportBeanDefinitionRegistrar, EnvironmentAware, ResourceLoaderAware, BeanFactoryAware {
+		ImportBeanDefinitionRegistrar, EnvironmentAware, ResourceLoaderAware, BeanFactoryAware, BeanClassLoaderAware {
 
 	/**
 	 * The bean name of the {@link HttpServiceProxyRegistry}.
@@ -91,6 +93,8 @@ public abstract class AbstractHttpServiceRegistrar implements
 
 	private @Nullable BeanFactory beanFactory;
 
+	private @Nullable ClassLoader beanClassLoader;
+
 	private final GroupsMetadata groupsMetadata = new GroupsMetadata();
 
 	private @Nullable ClassPathScanningCandidateComponentProvider scanner;
@@ -121,6 +125,11 @@ public abstract class AbstractHttpServiceRegistrar implements
 		this.beanFactory = beanFactory;
 	}
 
+	@Override
+	public void setBeanClassLoader(ClassLoader beanClassLoader) {
+		this.beanClassLoader = beanClassLoader;
+	}
+
 
 	@Override
 	public final void registerBeanDefinitions(
@@ -197,7 +206,7 @@ public abstract class AbstractHttpServiceRegistrar implements
 	private Object getProxyInstance(String groupName, String httpServiceType) {
 		Assert.state(this.beanFactory != null, "BeanFactory has not been set");
 		HttpServiceProxyRegistry registry = this.beanFactory.getBean(HTTP_SERVICE_PROXY_REGISTRY_BEAN_NAME, HttpServiceProxyRegistry.class);
-		return registry.getClient(groupName, GroupsMetadata.loadClass(httpServiceType));
+		return registry.getClient(groupName, ClassUtils.resolveClassName(httpServiceType, this.beanClassLoader));
 	}
 
 

spring-web/src/main/java/org/springframework/web/service/registry/GroupsMetadata.java

@@ -26,6 +26,8 @@ import java.util.function.BiConsumer;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
 
@@ -82,17 +84,11 @@ final class GroupsMetadata {
 	/**
 	 * Create the {@link HttpServiceGroup}s for all registrations.
 	 */
-	public Collection<HttpServiceGroup> groups() {
-		return this.groupMap.values().stream().map(DefaultRegistration::toHttpServiceGroup).toList();
-	}
-
-	public static Class<?> loadClass(String type) {
-		try {
-			return ClassUtils.forName(type, GroupsMetadata.class.getClassLoader());
-		}
-		catch (ClassNotFoundException ex) {
-			throw new IllegalStateException("Failed to load '" + type + "'", ex);
-		}
+	public Collection<HttpServiceGroup> groups(@Nullable ClassLoader classLoader) {
+		return this.groupMap.values()
+			.stream()
+			.map(registration -> registration.toHttpServiceGroup(classLoader))
+			.toList();
 	}
 
 	/**
@@ -169,10 +165,12 @@ final class GroupsMetadata {
 		/**
 		 * Create the {@link HttpServiceGroup} from the metadata.
 		 */
-		public HttpServiceGroup toHttpServiceGroup() {
+		public HttpServiceGroup toHttpServiceGroup(@Nullable ClassLoader classLoader) {
 			return new RegisteredGroup(this.name,
 					(this.clientType.isUnspecified() ? HttpServiceGroup.ClientType.REST_CLIENT : this.clientType),
-					this.typeNames.stream().map(GroupsMetadata::loadClass).collect(Collectors.toSet()));
+					this.typeNames.stream()
+						.map(typeName -> ClassUtils.resolveClassName(typeName, classLoader))
+						.collect(Collectors.toSet()));
 		}
 
 		@Override

spring-web/src/main/java/org/springframework/web/service/registry/HttpServiceProxyRegistryFactoryBean.java

@@ -31,6 +31,7 @@ import org.jspecify.annotations.Nullable;
 
 import org.springframework.beans.BeanUtils;
 import org.springframework.beans.BeansException;
+import org.springframework.beans.factory.BeanClassLoaderAware;
 import org.springframework.beans.factory.FactoryBean;
 import org.springframework.beans.factory.InitializingBean;
 import org.springframework.context.ApplicationContext;
@@ -57,27 +58,24 @@ import org.springframework.web.service.invoker.HttpServiceProxyFactory;
  * @see AbstractHttpServiceRegistrar
  */
 public final class HttpServiceProxyRegistryFactoryBean
-		implements ApplicationContextAware, InitializingBean, FactoryBean<HttpServiceProxyRegistry> {
+		implements ApplicationContextAware, BeanClassLoaderAware, InitializingBean,
+		FactoryBean<HttpServiceProxyRegistry> {
 
 	private static final Map<HttpServiceGroup.ClientType, HttpServiceGroupAdapter<?>> groupAdapters =
 			GroupAdapterInitializer.initGroupAdapters();
 
 
-	private final Set<ProxyHttpServiceGroup> groupSet;
+	private final GroupsMetadata groupsMetadata;
 
 	private @Nullable ApplicationContext applicationContext;
 
+	private @Nullable ClassLoader beanClassLoader;
+
 	private @Nullable HttpServiceProxyRegistry proxyRegistry;
 
 
 	HttpServiceProxyRegistryFactoryBean(GroupsMetadata groupsMetadata) {
-		this.groupSet = groupsMetadata.groups().stream()
-				.map(group -> {
-					HttpServiceGroupAdapter<?> adapter = groupAdapters.get(group.clientType());
-					Assert.state(adapter != null, "No HttpServiceGroupAdapter for type " + group.clientType());
-					return new ProxyHttpServiceGroup(group, adapter);
-				})
-				.collect(Collectors.toSet());
+		this.groupsMetadata = groupsMetadata;
 	}
 
 
@@ -86,6 +84,11 @@ public final class HttpServiceProxyRegistryFactoryBean
 		this.applicationContext = applicationContext;
 	}
 
+	@Override
+	public void setBeanClassLoader(ClassLoader beanClassLoader) {
+		this.beanClassLoader = beanClassLoader;
+	}
+
 	@Override
 	public Class<?> getObjectType() {
 		return HttpServiceProxyRegistry.class;
@@ -95,18 +98,25 @@ public final class HttpServiceProxyRegistryFactoryBean
 	@Override
 	public void afterPropertiesSet() {
 		Assert.notNull(this.applicationContext, "ApplicationContext not initialized");
+		Assert.notNull(this.beanClassLoader, "BeanClassLoader not initialized");
+
+		// Create the groups from the metadata
+		Set<ProxyHttpServiceGroup> groups = this.groupsMetadata.groups(this.beanClassLoader)
+			.stream()
+			.map(ProxyHttpServiceGroup::new)
+			.collect(Collectors.toSet());
 
 		// Apply group configurers
 		groupAdapters.forEach((clientType, groupAdapter) ->
 				this.applicationContext.getBeanProvider(groupAdapter.getConfigurerType())
 						.orderedStream()
-						.forEach(configurer -> configurer.configureGroups(new DefaultGroups<>(clientType))));
+						.forEach(configurer -> configurer.configureGroups(new DefaultGroups<>(groups, clientType))));
 
 		// Create proxies
-		Map<String, Map<Class<?>, Object>> groupProxyMap = this.groupSet.stream()
+		Map<String, Map<Class<?>, Object>> proxies = groups.stream()
 				.collect(Collectors.toMap(ProxyHttpServiceGroup::name, ProxyHttpServiceGroup::createProxies));
 
-		this.proxyRegistry = new DefaultHttpServiceProxyRegistry(groupProxyMap);
+		this.proxyRegistry = new DefaultHttpServiceProxyRegistry(proxies);
 	}
 
 
@@ -159,12 +169,17 @@ public final class HttpServiceProxyRegistryFactoryBean
 
 		private BiConsumer<HttpServiceGroup, HttpServiceProxyFactory.Builder> proxyFactoryConfigurer = (group, builder) -> {};
 
+		ProxyHttpServiceGroup(HttpServiceGroup group) {
+			this(group, getHttpServiceGroupAdapter(group.clientType()));
+		}
+
 		ProxyHttpServiceGroup(HttpServiceGroup group, HttpServiceGroupAdapter<?> groupAdapter) {
 			this.declaredGroup = group;
 			this.groupAdapter = groupAdapter;
 			this.clientBuilder = groupAdapter.createClientBuilder();
 		}
 
+
 		@Override
 		public String name() {
 			return this.declaredGroup.name();
@@ -208,17 +223,26 @@ public final class HttpServiceProxyRegistryFactoryBean
 		public String toString() {
 			return getClass().getSimpleName() + "[id=" + name() + "]";
 		}
+
+		private static HttpServiceGroupAdapter<?> getHttpServiceGroupAdapter(HttpServiceGroup.ClientType clientType) {
+			HttpServiceGroupAdapter<?> adapter = groupAdapters.get(clientType);
+			Assert.state(adapter != null, "No HttpServiceGroupAdapter for type " + clientType);
+			return adapter;
+		}
 	}
 
 
 	/**
 	 * Default implementation of Groups that helps to configure the set of declared groups.
 	 */
-	private final class DefaultGroups<CB> implements HttpServiceGroupConfigurer.Groups<CB> {
+	private static final class DefaultGroups<CB> implements HttpServiceGroupConfigurer.Groups<CB> {
+
+		private final Set<ProxyHttpServiceGroup> groups;
 
 		private Predicate<HttpServiceGroup> filter;
 
-		DefaultGroups(HttpServiceGroup.ClientType clientType) {
+		DefaultGroups(Set<ProxyHttpServiceGroup> groups, HttpServiceGroup.ClientType clientType) {
+			this.groups = groups;
 			this.filter = group -> group.clientType().equals(clientType);
 		}
 
@@ -255,7 +279,7 @@ public final class HttpServiceProxyRegistryFactoryBean
 				BiConsumer<HttpServiceGroup, CB> clientConfigurer,
 				BiConsumer<HttpServiceGroup, HttpServiceProxyFactory.Builder> proxyFactoryConfigurer) {
 
-			groupSet.stream().filter(this.filter).forEach(group ->
+			this.groups.stream().filter(this.filter).forEach(group ->
 					group.apply(clientConfigurer, proxyFactoryConfigurer));
 		}
 	}