What is the difference between BeanFactory and ApplicationContext in Spring?

BeanFactory is the most basic container interface, providing lazy initialization (beans are created only when first requested) and the fundamental DI capability. ApplicationContext extends BeanFactory and adds enterprise features on top — eager singleton initialization at startup, event publishing, internationalization support, and easier integration with Spring AOP — which is why virtually every real Spring/Spring Boot application uses ApplicationContext rather than BeanFactory directly.