Source file: Mandelbrot.java
Source file: Compiler.zip
Source file: Tetris.java
JAR file: JConfig.jar
The JAR file contains the JConfig source.
If a Java program is available from the main site but the source code is not listed above, the source code has simply not been released. It was not deemed interesting enough to justify the work of putting it in a "presentable" state. If you still want to read it, Jode is your friend.