<p>
      This Serializable class defines a non-primitive instance field which is neither transient, 
      Serializable, or <code>java.lang.Object</code>, and does not appear to implement the <code>Externalizable</code> 
      interface or the <code>readObject()</code> and <code>writeObject()</code> methods.  
      Objects of this class will not be deserialized correctly if a non-Serializable object is stored in this field.
      </p>