This week's book giveaway is in the OCPJP forum. We're giving away four copies of OCA/OCP Java SE 7 Programmer I & II Study Guide and have Kathy Sierra & Bert Bates on-line! See this thread for details.
It's not like that 'marker interface' does nothing? If you dig inside this 'Serializable' interface, you will come to know how does this work. There are 'writeObject' and 'readObject' kind of methods hidden behind the scene.