title: Serializing a class containing a non-serializable class
body: <p>I have two classes, <code>A</code> and <code>B</code>.</p>
  
  <p>Class <code>A</code> is developed by X company and is not serializable.</p>
  
  <p>Company Y is trying to use class <code>A</code> in class <code>B</code>, which must be serializable.</p>
  
  <p>How can this be done without changing class <code>A</code>? Is that what the externalization interface is for?</p>