Data management, Encapsulation, unimplemented methods

Hi, so first I try to make the classes to be more encapsulated by
changing some methods in Table classes to static (no change in method
name btw). Then, I implement the checkReservation method() to check for
reservation as it's necessarry, printOrderInvoice which fully print the
invoice, salesReport methods, and I also make the file system using
Serialization (very simple only 2 methods in 1 class ~ 25 lines). We
also able to print the menu, promotion or order to make the user to be
able to view it. I make the big picture of our interface to be in the
main Restaurant Class, you can finish it if u want, all of the needed
methods are already there, just make sure to compile first, since I just
copy and paste my codes from other directory in Eclipse...