code: public FieldDoc[] serializableFields() {
          if (serializedForm == null) {
              serializedForm = new SerializedForm(env, tsym, this);
          }
          //### Clone this?
          return serializedForm.fields();
      }
docs: Return the Serializable fields of class.<p>
  
  Return either a list of default fields documented by
  <code>serial</code> tag<br>
  or return a single <code>FieldDoc</code> for
  <code>serialPersistentField</code> member.
  There should be a <code>serialField</code> tag for
  each Serializable field defined by an <code>ObjectStreamField</code>
  array component of <code>serialPersistentField</code>.
  
  @return an array of {@code FieldDoc} for the Serializable fields
  of this class.
  
  @see #definesSerializableFields()
  @see SerialFieldTagImpl