Description: This article covers some important information to help you understand the backbone of this library. It is excerpted from the book Advanced Java Game Programming .this chapter, we examine in detail three interfaces and one class that form the backbone of the reusable Swing-based animation library. Additionally covered are one or more implementations of each interface. Understanding how these core classes operate is key to understanding the implementation trade-offs. It is also useful to understand how these classes work when it comes to creating and integrating your own animation classes to create a unique game.