title: Gson doesn't serialize fields defined in subclasses
body: <p>For some unknown reason if I have:</p>
  
  <pre><code>class A{
  int stars;
  public int getStars(){
  return stars;
  }
  
  public void setStarts(int stars){
  this.stars = stars;
  }
  }
  
  class B extends A{
   int sunshines;
  
  [getter and setter for sunshines]
  }
  
  class C{
   List&lt;A&gt; classes;
  [get and set for classes]
  }
  </code></pre>
  
  <p>if I serialize an Object of type C I have only the fields of A in the serialized objects in the field classes (while I would expect to have the fields of B if the object is a B).</p>
  
  <p>How to do that? </p>