Avoid stack overflow in case of chained factory-bean references to FactoryBean class

Issue: SPR-14551

spring-beans/src/main/java/org/springframework/beans/factory/BeanFactory.java

 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -114,6 +114,7 @@ public interface BeanFactory {
 	 */
 	String FACTORY_BEAN_PREFIX = "&";
 
+
 	/**
 	 * Return an instance, which may be shared or independent, of the specified bean.
 	 * <p>This method allows a Spring BeanFactory to be used as a replacement for the
@@ -151,15 +152,16 @@ public interface BeanFactory {
 
 	/**
 	 * Return the bean instance that uniquely matches the given object type, if any.
-	 * @param requiredType type the bean must match; can be an interface or superclass.
-	 * {@code null} is disallowed.
 	 * <p>This method goes into {@link ListableBeanFactory} by-type lookup territory
 	 * but may also be translated into a conventional by-name lookup based on the name
 	 * of the given type. For more extensive retrieval operations across sets of beans,
 	 * use {@link ListableBeanFactory} and/or {@link BeanFactoryUtils}.
+	 * @param requiredType type the bean must match; can be an interface or superclass.
+	 * {@code null} is disallowed.
 	 * @return an instance of the single bean matching the required type
 	 * @throws NoSuchBeanDefinitionException if no bean of the given type was found
 	 * @throws NoUniqueBeanDefinitionException if more than one bean of the given type was found
+	 * @throws BeansException if the bean could not be created
 	 * @since 3.0
 	 * @see ListableBeanFactory
 	 */
@@ -170,7 +172,7 @@ public interface BeanFactory {
 	 * <p>Allows for specifying explicit constructor arguments / factory method arguments,
 	 * overriding the specified default arguments (if any) in the bean definition.
 	 * @param name the name of the bean to retrieve
-	 * @param args arguments to use if creating a prototype using explicit arguments
+	 * @param args arguments to use when creating a prototype using explicit arguments
 	 * @return an instance of the bean
 	 * @throws NoSuchBeanDefinitionException if there is no such bean definition
 	 * @throws BeanDefinitionStoreException if arguments have been given but

spring-beans/src/main/java/org/springframework/beans/factory/NamedBean.java

 /*
- * Copyright 2002-2006 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -17,10 +17,10 @@
 package org.springframework.beans.factory;
 
 /**
- * Counterpart of BeanNameAware. Returns the bean name of an object.
+ * Counterpart of {@link BeanNameAware}. Returns the bean name of an object.
  *
- * <p>This interface can be introduced to avoid a brittle dependence
- * on bean name in objects used with Spring IoC and Spring AOP.
+ * <p>This interface can be introduced to avoid a brittle dependence on
+ * bean name in objects used with Spring IoC and Spring AOP.
  *
  * @author Rod Johnson
  * @since 2.0
@@ -29,7 +29,7 @@ package org.springframework.beans.factory;
 public interface NamedBean {
 
 	/**
-	 * Return the name of this bean in a Spring bean factory.
+	 * Return the name of this bean in a Spring bean factory, if known.
 	 */
 	String getBeanName();
 

spring-beans/src/main/java/org/springframework/beans/factory/config/AutowireCapableBeanFactory.java

 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -114,9 +114,9 @@ public interface AutowireCapableBeanFactory extends BeanFactory {
 	 * <p>Performs full initialization of the bean, including all applicable
 	 * {@link BeanPostProcessor BeanPostProcessors}.
 	 * <p>Note: This is intended for creating a fresh instance, populating annotated
-	 * fields and methods as well as applying all standard bean initialiation callbacks.
+	 * fields and methods as well as applying all standard bean initialization callbacks.
 	 * It does <i>not</> imply traditional by-name or by-type autowiring of properties;
-	 * use {@link #createBean(Class, int, boolean)} for that purposes.
+	 * use {@link #createBean(Class, int, boolean)} for those purposes.
 	 * @param beanClass the class of the bean to create
 	 * @return the new bean instance
 	 * @throws BeansException if instantiation or wiring failed
@@ -129,7 +129,7 @@ public interface AutowireCapableBeanFactory extends BeanFactory {
 	 * <p>Note: This is essentially intended for (re-)populating annotated fields and
 	 * methods, either for new instances or for deserialized instances. It does
 	 * <i>not</i> imply traditional by-name or by-type autowiring of properties;
-	 * use {@link #autowireBeanProperties} for that purposes.
+	 * use {@link #autowireBeanProperties} for those purposes.
 	 * @param existingBean the existing bean instance
 	 * @throws BeansException if wiring failed
 	 */

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

 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -425,9 +425,7 @@ public abstract class AbstractAutowireCapableBeanFactory extends AbstractBeanFac
 	 * @see #doCreateBean
 	 */
 	@Override
-	protected Object createBean(final String beanName, final RootBeanDefinition mbd, final Object[] args)
-			throws BeanCreationException {
-
+	protected Object createBean(String beanName, RootBeanDefinition mbd, Object[] args) throws BeanCreationException {
 		if (logger.isDebugEnabled()) {
 			logger.debug("Creating instance of bean '" + beanName + "'");
 		}
@@ -596,7 +594,7 @@ public abstract class AbstractAutowireCapableBeanFactory extends AbstractBeanFac
 	}
 
 	/**
-	 * Determine the bean type for the given bean definition which is based on
+	 * Determine the target type for the given bean definition which is based on
 	 * a factory method. Only called if there is no singleton instance registered
 	 * for the target bean already.
 	 * <p>This implementation determines the type matching {@link #createBean}'s
@@ -606,7 +604,7 @@ public abstract class AbstractAutowireCapableBeanFactory extends AbstractBeanFac
 	 * @param mbd the merged bean definition for the bean
 	 * @param typesToMatch the types to match in case of internal type matching purposes
 	 * (also signals that the returned {@code Class} will never be exposed to application code)
-	 * @return the type for the bean if determinable, or {@code null} else
+	 * @return the type for the bean if determinable, or {@code null} otherwise
 	 * @see #createBean
 	 */
 	protected Class<?> getTypeForFactoryMethod(String beanName, RootBeanDefinition mbd, Class[] typesToMatch) {
@@ -745,10 +743,14 @@ public abstract class AbstractAutowireCapableBeanFactory extends AbstractBeanFac
 			if (objectType.value != null) {
 				return objectType.value;
 			}
+			else {
+				// No type found for shortcut FactoryBean instance:
+				// fall back to full creation of the FactoryBean instance.
+				return super.getTypeForFactoryBean(beanName, mbd);
+			}
 		}
 
-		// No type found - fall back to full creation of the FactoryBean instance.
-		return super.getTypeForFactoryBean(beanName, mbd);
+		return null;
 	}
 
 	/**
@@ -767,7 +769,7 @@ public abstract class AbstractAutowireCapableBeanFactory extends AbstractBeanFac
 					SmartInstantiationAwareBeanPostProcessor ibp = (SmartInstantiationAwareBeanPostProcessor) bp;
 					exposedObject = ibp.getEarlyBeanReference(exposedObject, beanName);
 					if (exposedObject == null) {
-						return exposedObject;
+						return null;
 					}
 				}
 			}
@@ -782,8 +784,7 @@ public abstract class AbstractAutowireCapableBeanFactory extends AbstractBeanFac
 
 	/**
 	 * Obtain a "shortcut" singleton FactoryBean instance to use for a
-	 * {@code getObjectType()} call, without full initialization
-	 * of the FactoryBean.
+	 * {@code getObjectType()} call, without full initialization of the FactoryBean.
 	 * @param beanName the name of the bean
 	 * @param mbd the bean definition for the bean
 	 * @return the FactoryBean instance, or {@code null} to indicate
@@ -824,8 +825,7 @@ public abstract class AbstractAutowireCapableBeanFactory extends AbstractBeanFac
 
 	/**
 	 * Obtain a "shortcut" non-singleton FactoryBean instance to use for a
-	 * {@code getObjectType()} call, without full initialization
-	 * of the FactoryBean.
+	 * {@code getObjectType()} call, without full initialization of the FactoryBean.
 	 * @param beanName the name of the bean
 	 * @param mbd the bean definition for the bean
 	 * @return the FactoryBean instance, or {@code null} to indicate