Polishing (in particular updating javadoc references to Apache Commons)

(cherry picked from commit bc6a98c)

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

@@ -804,7 +804,7 @@ public class DefaultListableBeanFactory extends AbstractAutowireCapableBeanFacto
 
 		oldBeanDefinition = this.beanDefinitionMap.get(beanName);
 		if (oldBeanDefinition != null) {
-			if (!this.allowBeanDefinitionOverriding) {
+			if (!isAllowBeanDefinitionOverriding()) {
 				throw new BeanDefinitionStoreException(beanDefinition.getResourceDescription(), beanName,
 						"Cannot register bean definition [" + beanDefinition + "] for bean '" + beanName +
 						"': There is already [" + oldBeanDefinition + "] bound.");