title: Annotation vs marker interface in Spring MVC
body: <p>Which do you prefer? In spring mvc, they use <code>@Controller</code> for all <code>Controller</code> classes. Could they have used some marker interface? Why did they select the annotation approach? 
  Better yet, they can have something similar to <code>controller-scan</code> similar to <code>component-scan</code> so any classes in the package can be assumed to a Controller class. Similarly <code>service-scan</code> and <code>repository-scan</code> can be defined in xml.</p>