If you're downloading a J2SE version older than 1.2, you'll have to get the JFC/Swing classes from the JavaSoft site (http://java.sun.com/products/jfc/#download-swing). Make sure your J2SE and JFC versions match—for example, if you have J2SE v.1.1.7, you need Swing v.1.1.1 (swing1_1_1.tar.Z).
The download page doesn't mention Linux, so choose the standard tar or zip file, not the installer.
In a shell, as root, or with the su command, copy or move the downloaded file to the directory you choose. As before, we're using /usr/local/lib and we want the swing-1.1.x directory (/usr/local/lib/jdk1.1.7/swing-1.1.x), so we move the file to /usr/local/lib/jdk1.1.7/. Installing the Swing classes in the J2SE directory ...