LazyInitTargetSource works for @Bean targets as well

Issue: SPR-10508
Issue: SPR-8080

spring-beans/src/main/java/org/springframework/beans/factory/support/ConstructorResolver.java

@@ -372,6 +372,10 @@ class ConstructorResolver {
 				throw new BeanCreationException(mbd.getResourceDescription(), beanName,
 						"factory-bean '" + factoryBeanName + "' (or a BeanPostProcessor involved) returned null");
 			}
+			if (mbd.isSingleton() && this.beanFactory.containsSingleton(beanName)) {
+				throw new IllegalStateException("About-to-be-created singleton instance implicitly appeared " +
+						"through the creation of the factory bean that its bean definition points to");
+			}
 			factoryClass = factoryBean.getClass();
 			isStatic = false;
 		}
@@ -904,4 +908,5 @@ class ConstructorResolver {
 			}
 		}
 	}
+
 }

spring-beans/src/main/java/org/springframework/beans/factory/support/DefaultSingletonBeanRegistry.java

@@ -220,12 +220,22 @@ public class DefaultSingletonBeanRegistry extends SimpleAliasRegistry implements
 					logger.debug("Creating shared instance of singleton bean '" + beanName + "'");
 				}
 				beforeSingletonCreation(beanName);
+				boolean newSingleton = false;
 				boolean recordSuppressedExceptions = (this.suppressedExceptions == null);
 				if (recordSuppressedExceptions) {
 					this.suppressedExceptions = new LinkedHashSet<Exception>();
 				}
 				try {
 					singletonObject = singletonFactory.getObject();
+					newSingleton = true;
+				}
+				catch (IllegalStateException ex) {
+					// Has the singleton object implicitly appeared in the meantime ->
+					// if yes, proceed with it since the exception indicates that state.
+					singletonObject = this.singletonObjects.get(beanName);
+					if (singletonObject == null) {
+						throw ex;
+					}
 				}
 				catch (BeanCreationException ex) {
 					if (recordSuppressedExceptions) {
@@ -241,7 +251,9 @@ public class DefaultSingletonBeanRegistry extends SimpleAliasRegistry implements
 					}
 					afterSingletonCreation(beanName);
 				}
-				addSingleton(beanName, singletonObject);
+				if (newSingleton) {
+					addSingleton(beanName, singletonObject);
+				}
 			}
 			return (singletonObject != NULL_OBJECT ? singletonObject : null);
 		}

spring-context/src/main/java/org/springframework/context/annotation/ConfigurationClassEnhancer.java

@@ -296,7 +296,7 @@ class ConfigurationClassEnhancer {
 				}
 			}
 
-			if (isCurrentlyInvokedFactoryMethod(beanMethod) && !beanFactory.containsSingleton(beanName)) {
+			if (isCurrentlyInvokedFactoryMethod(beanMethod)) {
 				// The factory is calling the bean method in order to instantiate and register the bean
 				// (i.e. via a getBean() call) -> invoke the super implementation of the method to actually
 				// create the bean instance.
@@ -306,7 +306,7 @@ class ConfigurationClassEnhancer {
 							"result in a failure to process annotations such as @Autowired, " +
 							"@Resource and @PostConstruct within the method's declaring " +
 							"@Configuration class. Add the 'static' modifier to this method to avoid " +
-							"these container lifecycle issues; see @Bean Javadoc for complete details",
+							"these container lifecycle issues; see @Bean javadoc for complete details",
 							beanMethod.getDeclaringClass().getSimpleName(), beanMethod.getName()));
 				}
 				return cglibMethodProxy.invokeSuper(enhancedConfigInstance, beanMethodArgs);

spring-context/src/test/java/org/springframework/context/annotation/AutoProxyLazyInitTests.java

@@ -0,0 +1,223 @@
+/*
+ * Copyright 2002-2014 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
+ *
+ *      http://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.context.annotation;
+
+import javax.annotation.PreDestroy;
+
+import org.junit.Test;
+
+import org.springframework.aop.framework.autoproxy.BeanNameAutoProxyCreator;
+import org.springframework.aop.framework.autoproxy.target.LazyInitTargetSourceCreator;
+import org.springframework.aop.target.AbstractBeanFactoryBasedTargetSource;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.ApplicationListener;
+import org.springframework.context.event.ApplicationContextEvent;
+
+import static org.junit.Assert.*;
+
+/**
+ * @author Juergen Hoeller
+ * @author Arrault Fabien
+ */
+public class AutoProxyLazyInitTests {
+
+	@Test
+	public void withStaticBeanMethod() {
+		MyBeanImpl.initialized = false;
+
+		ApplicationContext ctx = new AnnotationConfigApplicationContext(ConfigWithStatic.class);
+		MyBean bean = ctx.getBean("myBean", MyBean.class);
+		
+		assertFalse(MyBeanImpl.initialized);
+		bean.doIt();
+		assertTrue(MyBeanImpl.initialized);
+	}
+
+	@Test
+	public void withStaticBeanMethodAndInterface() {
+		MyBeanImpl.initialized = false;
+
+		ApplicationContext ctx = new AnnotationConfigApplicationContext(ConfigWithStaticAndInterface.class);
+		MyBean bean = ctx.getBean("myBean", MyBean.class);
+
+		assertFalse(MyBeanImpl.initialized);
+		bean.doIt();
+		assertTrue(MyBeanImpl.initialized);
+	}
+
+	@Test
+	public void withNonStaticBeanMethod() {
+		MyBeanImpl.initialized = false;
+
+		ApplicationContext ctx = new AnnotationConfigApplicationContext(ConfigWithNonStatic.class);
+		MyBean bean = ctx.getBean("myBean", MyBean.class);
+
+		assertFalse(MyBeanImpl.initialized);
+		bean.doIt();
+		assertTrue(MyBeanImpl.initialized);
+	}
+
+	@Test
+	public void withNonStaticBeanMethodAndInterface() {
+		MyBeanImpl.initialized = false;
+
+		ApplicationContext ctx = new AnnotationConfigApplicationContext(ConfigWithNonStaticAndInterface.class);
+		MyBean bean = ctx.getBean("myBean", MyBean.class);
+
+		assertFalse(MyBeanImpl.initialized);
+		bean.doIt();
+		assertTrue(MyBeanImpl.initialized);
+	}
+
+
+	public static interface MyBean {
+
+		public String doIt();
+	}
+
+
+	public static class MyBeanImpl implements MyBean {
+
+		public static boolean initialized = false;
+
+		public MyBeanImpl() {
+			initialized = true;
+		}
+
+		@Override
+		public String doIt() {
+			return "From implementation";
+		}
+
+		@PreDestroy
+		public void destroy() {
+		}
+	}
+
+
+	@Configuration
+	public static class ConfigWithStatic {
+
+		@Bean
+		public BeanNameAutoProxyCreator lazyInitAutoProxyCreator() {
+			BeanNameAutoProxyCreator autoProxyCreator = new BeanNameAutoProxyCreator();
+			autoProxyCreator.setCustomTargetSourceCreators(lazyInitTargetSourceCreator());
+			return autoProxyCreator;
+		}
+
+		@Bean
+		public LazyInitTargetSourceCreator lazyInitTargetSourceCreator() {
+			return new StrictLazyInitTargetSourceCreator();
+		}
+
+		@Bean
+		@Lazy
+		public static MyBean myBean() {
+			return new MyBeanImpl();
+		}
+	}
+
+
+	@Configuration
+	public static class ConfigWithStaticAndInterface implements ApplicationListener<ApplicationContextEvent> {
+
+		@Bean
+		public BeanNameAutoProxyCreator lazyInitAutoProxyCreator() {
+			BeanNameAutoProxyCreator autoProxyCreator = new BeanNameAutoProxyCreator();
+			autoProxyCreator.setCustomTargetSourceCreators(lazyInitTargetSourceCreator());
+			return autoProxyCreator;
+		}
+
+		@Bean
+		public LazyInitTargetSourceCreator lazyInitTargetSourceCreator() {
+			return new StrictLazyInitTargetSourceCreator();
+		}
+
+		@Bean
+		@Lazy
+		public static MyBean myBean() {
+			return new MyBeanImpl();
+		}
+
+		@Override
+		public void onApplicationEvent(ApplicationContextEvent event) {
+		}
+	}
+
+
+	@Configuration
+	public static class ConfigWithNonStatic {
+
+		@Bean
+		public BeanNameAutoProxyCreator lazyInitAutoProxyCreator() {
+			BeanNameAutoProxyCreator autoProxyCreator = new BeanNameAutoProxyCreator();
+			autoProxyCreator.setCustomTargetSourceCreators(lazyInitTargetSourceCreator());
+			return autoProxyCreator;
+		}
+
+		@Bean
+		public LazyInitTargetSourceCreator lazyInitTargetSourceCreator() {
+			return new StrictLazyInitTargetSourceCreator();
+		}
+
+		@Bean
+		@Lazy
+		public MyBean myBean() {
+			return new MyBeanImpl();
+		}
+	}
+
+
+	@Configuration
+	public static class ConfigWithNonStaticAndInterface implements ApplicationListener<ApplicationContextEvent> {
+
+		@Bean
+		public BeanNameAutoProxyCreator lazyInitAutoProxyCreator() {
+			BeanNameAutoProxyCreator autoProxyCreator = new BeanNameAutoProxyCreator();
+			autoProxyCreator.setCustomTargetSourceCreators(lazyInitTargetSourceCreator());
+			return autoProxyCreator;
+		}
+
+		@Bean
+		public LazyInitTargetSourceCreator lazyInitTargetSourceCreator() {
+			return new StrictLazyInitTargetSourceCreator();
+		}
+
+		@Bean
+		@Lazy
+		public MyBean myBean() {
+			return new MyBeanImpl();
+		}
+
+		@Override
+		public void onApplicationEvent(ApplicationContextEvent event) {
+		}
+	}
+
+
+	private static class StrictLazyInitTargetSourceCreator extends LazyInitTargetSourceCreator {
+
+		@Override
+		protected AbstractBeanFactoryBasedTargetSource createBeanFactoryBasedTargetSource(Class<?> beanClass, String beanName) {
+			if ("myBean".equals(beanName)) {
+				assertEquals(MyBean.class, beanClass);
+			}
+			return super.createBeanFactoryBasedTargetSource(beanClass, beanName);
+		}
+	}
+
+}