anchor.diff:  In <<mvc-config>> you'll learn about other options for configuring Spring MVC including
   MVC Java config and the MVC XML namespace both of which provide a simple starting point
   and assume little knowledge of how Spring MVC works. Regardless of how you choose to
  -configure your application, the concepts explained in this section are fundamental
  +configure your application, the concepts explained in this section are fundamental and
   should be of help to you.
   
   
  
positive.code: 
  * Request or response objects (Servlet API). Choose any specific request or response
    type, for example `ServletRequest` or `HttpServletRequest`.
  * Session object (Servlet API): of type `HttpSession`. An argument of this type enforces
    the presence of a corresponding session. As a consequence, such an argument is never
    `null`.
  
  
negative.code: [NOTE]
  ====
  JDK 1.8's `java.util.Optional` is supported as a method parameter type with annotations
  that have a `required` attribute (e.g. `@RequestParam`, `@RequestHeader`, etc). The use
  of `java.util.Optional` in those cases is equivalent to having `required=false`.
  ====
  
  