Spring provides two main types of IoC (Inversion of Control) containers: BeanFactory and ApplicationContext. Both are responsible for creating, configuring, and managing Spring Beans, but ApplicationContext offers additional enterprise-level features and is the most commonly used container.
Key Points: • BeanFactory is the basic IoC container that provides bean creation and dependency injection. • BeanFactory uses lazy initialization, meaning beans are created only when requested. • ApplicationContext is an advanced IoC container built on top of BeanFactory. • ApplicationContext supports features such as event handling, internationalization (i18n), annotation-based configuration, and integration with Spring modules. • Most modern Spring applications use ApplicationContext because of its richer functionality and better developer experience.
Example: In a simple application, BeanFactory can be used to create and manage beans. In enterprise applications, ApplicationContext is preferred because it provides additional features such as event publishing and automatic bean post-processing.
Interview Tip: A concise interview answer is:
"Spring has two IoC containers: BeanFactory and ApplicationContext. BeanFactory provides basic bean management and dependency injection, while ApplicationContext extends BeanFactory with advanced features such as event handling, internationalization, and annotation support. ApplicationContext is the preferred choice in modern Spring applications."