The Application Context

The booking project defines 9 beans of its own: BookingService, Notifier, PaymentClient, and six others. When we started the service and counted the bean definitions in its container, the count was 153.

The 144 extra definitions came from Spring and from auto-configuration. The container wrote each definition, a description of one bean, before it created that bean. The object that holds these descriptions and creates the beans is Spring's real container. What follows covers what it is, what it records for each bean, how it finds your classes, and how to ask it questions.