Learning Java, 5th Edition

Chapter 10. Desktop Applications

Java leapt to fame and glory on the power of applets—amazing, interactive elements on a web page. Sounds mundane these days, but at the time it was nothing short of a marvel. But Java also had cross-platform support up its sleeve and could run the same code on Windows, Unix, and macOS systems. The early JDKs had a rudimentary set of graphical components collectively known as the Abstract Window Toolkit (AWT). The “abstract” in AWT comes from the use of common classes (Button, Window, etc.) with native implementations. You write AWT applications with abstract, cross-platform code; your computer runs your application and provides concrete, native components.

That nifty combination of abstract and native comes with some pretty serious limitations, unfortunately. In the abstract realm, you encounter “lowest common denominator” designs that only give you access to features available on every platform Java supports. In native implementations even some features roughly available everywhere were distinctly different when actually rendered on the screen. Many desktop developers working with Java in those early days joked that the “write once, run everywhere” tagline was really “write once, debug everywhere.” The Java Swing package set out to ameliorate this woeful state. While Swing didn’t solve every problem of cross-platform application delivery, it did make serious desktop application development possible in Java. You can find many quality open source ...