title: Design patterns exercise in Java
body: <p>Hi
  I have an assignment to teach a team the subject of design principle. As a final exercise to this mini course, I thought to give them an exercise in design pattern, in Java.
  My idea is to give them a code written badly, and they should refactor it using several design patterns. I didn't find anything similar to that in my search (both in the web and in stack overflow).</p>
  
  <p>Any references to something similar to what I'm looking for?</p>
  
  <p>Thanks</p>