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.
Remember that a File is just an abstract representation of a file/directory pathname.
The File class already overrides writeObject and readObject to make the path system independent when serializing and de-serializing on different systems.