ProxyFactoryBean determines actual proxy class in getObjectType()

AopProxy implementations accept empty Advisor chains for early proxy class creation.

Closes gh-29097

Author: jhoeller

spring-aop/src/main/java/org/springframework/aop/framework/CglibAopProxy.java

@@ -126,9 +126,6 @@ class CglibAopProxy implements AopProxy, Serializable {
 	 */
 	public CglibAopProxy(AdvisedSupport config) throws AopConfigException {
 		Assert.notNull(config, "AdvisedSupport must not be null");
-		if (config.getAdvisorCount() == 0 && config.getTargetSource() == AdvisedSupport.EMPTY_TARGET_SOURCE) {
-			throw new AopConfigException("No advisors and no TargetSource specified");
-		}
 		this.advised = config;
 		this.advisedDispatcher = new AdvisedDispatcher(this.advised);
 	}

spring-aop/src/main/java/org/springframework/aop/framework/JdkDynamicAopProxy.java

@@ -104,9 +104,6 @@ final class JdkDynamicAopProxy implements AopProxy, InvocationHandler, Serializa
 	 */
 	public JdkDynamicAopProxy(AdvisedSupport config) throws AopConfigException {
 		Assert.notNull(config, "AdvisedSupport must not be null");
-		if (config.getAdvisorCount() == 0 && config.getTargetSource() == AdvisedSupport.EMPTY_TARGET_SOURCE) {
-			throw new AopConfigException("No advisors and no TargetSource specified");
-		}
 		this.advised = config;
 		this.proxiedInterfaces = AopProxyUtils.completeProxiedInterfaces(this.advised, true);
 		findDefinedEqualsAndHashCodeMethods(this.proxiedInterfaces);

spring-aop/src/main/java/org/springframework/aop/framework/ProxyFactoryBean.java

@@ -274,19 +274,9 @@ public Class<?> getObjectType() {
 				return this.singletonInstance.getClass();
 			}
 		}
-		Class<?>[] ifcs = getProxiedInterfaces();
-		if (ifcs.length == 1) {
-			return ifcs[0];
-		}
-		else if (ifcs.length > 1) {
-			return createCompositeInterface(ifcs);
-		}
-		else if (this.targetName != null && this.beanFactory != null) {
-			return this.beanFactory.getType(this.targetName);
-		}
-		else {
-			return getTargetClass();
-		}
+		// This might be incomplete since it potentially misses introduced interfaces
+		// from Advisors that will be lazily retrieved via setInterceptorNames.
+		return createAopProxy().getProxyClass(this.proxyClassLoader);
 	}
 
 	@Override
@@ -295,19 +285,6 @@ public boolean isSingleton() {
 	}
 
 
-	/**
-	 * Create a composite interface Class for the given interfaces,
-	 * implementing the given interfaces in one single Class.
-	 * <p>The default implementation builds a JDK proxy class for the
-	 * given interfaces.
-	 * @param interfaces the interfaces to merge
-	 * @return the merged interface as Class
-	 * @see java.lang.reflect.Proxy#getProxyClass
-	 */
-	protected Class<?> createCompositeInterface(Class<?>[] interfaces) {
-		return ClassUtils.createCompositeInterface(interfaces, this.proxyClassLoader);
-	}
-
 	/**
 	 * Return the singleton instance of this class's proxy object,
 	 * lazily creating it if it hasn't been created already.

spring-context/src/test/java/org/springframework/aop/framework/AbstractAopProxyTests.java

@@ -97,12 +97,12 @@ public abstract class AbstractAopProxyTests {
 	 * to ensure that it was used appropriately by code.
 	 */
 	@BeforeEach
-	public void setUp() {
+	public void reset() {
 		mockTargetSource.reset();
 	}
 
 	@AfterEach
-	public void tearDown() {
+	public void verify() {
 		mockTargetSource.verify();
 	}
 
@@ -122,16 +122,6 @@ protected boolean requiresTarget() {
 	}
 
 
-	@Test
-	public void testNoInterceptorsAndNoTarget() {
-		assertThatExceptionOfType(AopConfigException.class).isThrownBy(() -> {
-				AdvisedSupport pc = new AdvisedSupport(ITestBean.class);
-				//Add no interceptors
-				AopProxy aop = createAopProxy(pc);
-				aop.getProxy();
-		});
-	}
-
 	/**
 	 * Simple test that if we set values we can get them out again.
 	 */

spring-context/src/test/java/org/springframework/aop/framework/ProxyFactoryBeanTests.java

@@ -92,7 +92,7 @@ public class ProxyFactoryBeanTests {
 
 
 	@BeforeEach
-	public void setUp() throws Exception {
+	public void setup() throws Exception {
 		DefaultListableBeanFactory parent = new DefaultListableBeanFactory();
 		parent.registerBeanDefinition("target2", new RootBeanDefinition(TestApplicationListener.class));
 		this.factory = new DefaultListableBeanFactory(parent);
@@ -473,8 +473,8 @@ public void testNoInterceptorNamesWithTarget() {
 	public void testEmptyInterceptorNames() {
 		DefaultListableBeanFactory bf = new DefaultListableBeanFactory();
 		new XmlBeanDefinitionReader(bf).loadBeanDefinitions(new ClassPathResource(INVALID_CONTEXT, CLASS));
-		assertThatExceptionOfType(BeanCreationException.class).as("Interceptor names cannot be empty").isThrownBy(() ->
-				bf.getBean("emptyInterceptorNames"));
+		assertThat(bf.getBean("emptyInterceptorNames")).isInstanceOf(ITestBean.class);
+		assertThat(Proxy.isProxyClass(bf.getBean("emptyInterceptorNames").getClass())).isTrue();
 	}
 
 	/**
@@ -709,6 +709,7 @@ public DependsOnITestBean(ITestBean tb) {
 		}
 	}
 
+
 	/**
 	 * Aspect interface
 	 */