SWT Programming with Eclipse

"The best way to predict the future is to invent it."—Alan Kay

1. Why SWT?

SWT is a cross platform GUI developed by IBM. Why has IBM created another GUI? Why have not they used existing Java GUI frameworks? To answer those questions, we need to go back to the early days of Java.

Sun has created a cross platform GUI framework AWT (Abstract Windowing Toolkit). The AWT framework uses native widgets but it was suffering from a LCD problem. The LCD problem causes loss of major platform features. In other words, if platform A has widgets 1–40 and platform B has widgets 20–25, the cross-platform AWT framework only offers the intersection of these two sets.

To solve this problem, Sun has created a new framework that uses emulated widgets instead of native widgets. This approach solved the LCD problem and provided a rich set of widgets but it has created other problems. For instance, Swing applications no longer look like native applications. Although they're the latest improvements in the JVM, Swing applications suffer performance problems that do not exist in their native counterparts. Moreover, Swing applications consume too much memory, which is not suitable for small devices such as PDAs and Mobile Phones.

IBM has decided that neither of the approaches fulfill their requirements. Consequently, IBM has created a new GUI library, called SWT,which solves the problems seen with the AWT and the Swing frameworks. The SWT framework accesses native widgets through JNI. If a widget is not available on the host platform, SWT emulates the unavailable widget.