Defining Spring application context

Every Spring application requires a context, a place where every component is registered. We could think about it like a central directory of object instances created by our application. When we use the Spring Framework and create something, for example, a connection pool, it gets registered in our context or when we create our own components they will be registered as well. So, if in another part of the application we require that component, instead of creating it again we can just access it. However, this provides more advanced features. If we want, for example, to register a controller that handles HTTP requests, as we do in our example, we could just do it anywhere in our classes. Later, the application could use the component scan to find what controllers we have and wire them to web interfaces, without requiring any configuration. Let's understand the component scan better in the following section.