Uses of readObject/writeObject in Serialization

Question

I was going through this article to understand more about Java Serialization process. When it comes to uses of readObject/writeObject I could see two use cases:

Answer 1

You can implement you own readObject/writeObject for performance reasons, or backward compatibility reasons, or because a field you want to serialize is not Serializable.

For good examples of readObject/writeObject I would look in the source which comes with the JDK. Or I would try http://www.google.co.uk/search?q=readObject+writeObject+examples