The JGoodies animation library provides an animation infrastructure for incorporating animations into Swing-based splash screens and other user-interface elements. After reading this article’s introduction to that library, you might want to explore the library’s source code (found in animation-1.1.3-src.zip, which locates in the same animation-1.1.3 directory as the Jar file) to learn more about the animation library.
As you continue to explore the animation library, I encourage you to also download and explore the other four JGoodies libraries: binding, forms, looks, and validation. For demonstrations of these five libraries, you can download JGoodies freeware, such as JDiskReport and Looks Demo. After discovering for yourself how animation and the other four libraries can help you radically improve your Swing GUIs, you might even want to purchase the JGoodies Swing Suite product, which consists of all five libraries and much more.