This example demonstrate the very basic progr of Spring Framework. In the example dependency injection concept of spring framework is illustrated using spring-context module. As we know spring is moduler by design. Here only spring-context dependency is being used to write the programe.
Here we have picked an example of a smart phone user who wants to make a call over a network. If we break this up, we could structure this example in couple of entities like User, SmartPhone and NetworkService provider.