code: private void writeObject(ObjectOutputStream oos) throws IOException
  	{
  
  		oos.defaultWriteObject();
  
  		synchronized (bcsListeners)
  		{
  			serialize(oos, bcsListeners);
  		}
  	}
docs: The implementation goes through following steps:
  <p>
  <ol>
  <li>Calls <code>defaultWriteObject()</code>.</li>
  <li>Writes out serializable service listeners.</li>
  </ol>
  </p>
  
  @param oos
  the object output stream
  @throws IOException
  if I/O exception occurs