anchor.diff:  
   [TIP]
   ====
  -
   The use of `<context:component-scan>` implicitly enables the functionality of
   `<context:annotation-config>`. There is usually no need to include the
   `<context:annotation-config>` element when using `<context:component-scan>`.
  
positive.code: 
  [TIP]
  ====
  
  Experienced Spring users will be familiar with the XML declaration equivalent from
  Spring's `context:` namespace
  
  
negative.code: 
  [TIP]
  ====
  You can use the `PropertyPlaceholderConfigurer` to substitute class names, which is
  sometimes useful when you have to pick a particular implementation class at runtime. For
  example:
  