As you might know, Swing was not the first GUI framework created by SUN. The first one was called as the Abstract Window Toolkit(AWT, shortly). AWT worked very similar to how other GUI tools, like, for eg., Visual Basic worked. It worked by translating the components it provided into platform specific counter parts called as native-peers. Thus, AWT components are sometimes referred to as heavy weight components.

    Due to this behavior of AWT, the look and feel of components looked exactly as the operating system wants to. While AWT had other problems, this problem clearly threatened the WORA(write-once-run-anywhere) philosophy of Java. Even simple things like cut and paste worked differently on different Operating Systems. The other problem was that some operating systems supported a richer set of component set while other did not. So AWT had to stick with the minimum se t of components (like textfields and buttons), so that it will work everywhere.

    These problems, made the designers stop further AWT development and start with Swing in 1997, that solved these problems. The basic Idea of Swing is that, look and feel of components are not decided by the Operating System, but by Java itself. After deciding the Look and Feel of component, it would then ask the Operating System to paint it as an image(Image cells are supported by all Operating Systems). Due to this behavior Swing components are sometimes said to be lightweight.

    Swing was first available as a separate download-able library, while today, is a Part of JFC and every JVM ships with swing.