This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
Thanks Bear. I'll try the abstract idea, but the private constructor idea can't work. If a subclass extends a superclass, the superclass' constructorwill be called before the subclass'. If the superclass' constructor is private, it will through a compile-time error.