In a Spring-based application, our application objects live within an object container. This container creates objects and associations between objects, and manages their complete life cycle. These container objects are called Spring-managed beans (or simply beans), and the container is called an application context in the Spring world.

A Spring container uses dependency injection (DI) to manage the beans that make up an application. An application context (org.springframework.context.ApplicationContext) creates beans and associate beans together based on the bean configuration and dispenses beans on request. A bean configuration can be defined via an XML file, annotation, or even via Java configuration classes. We will use only XML- and annotation-based bean configurations in our chapters.

A web application context is the extension of an application context, designed to work with the standard servlet context (javax.servlet.ServletContext). A web application context...