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: 
  For comprehensive protection against RFD, prior to rendering the response body
  Spring MVC adds a `Content-Disposition:inline;filename=f.txt` header to
  suggest a fixed and safe download file filename. This is done only if the URL
  path contains a file extension that is neither whitelisted nor explicitly
  registered for content negotiation purposes. However it may potentially have
  side effects when URLs are typed directly into a browser.
  
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`.
  ====
  
  