protected DefaultListableBeanFactory buildInternalBeanFactory(ConfigurableBeanFactory containingFactory) {
// Set parent so that references (up container hierarchies) are correctly resolved.
DefaultListableBeanFactory internalBeanFactory = new DefaultListableBeanFactory(containingFactory);
// Required so that all BeanPostProcessors, Scopes, etc become available.
internalBeanFactory.copyConfigurationFrom(containingFactory);
// Filter out BeanPostProcessors that are part of the AOP infrastructure,
// since those are only meant to apply to beans defined in the original factory.
for (Iterator<BeanPostProcessor> it = internalBeanFactory.getBeanPostProcessors().iterator(); it.hasNext();) {
if (it.next() instanceof AopInfrastructureBean) {