Note: Since Java 6 release, an updated version of this text, including the code samples, is available as part of the Swing trail of Java Tutorial:
How to Use GroupLayout, GroupLayout example
GroupLayout is a new layout manager that was developed as a
Swing Labs project in conjunction
with Matisse, the new GUI builder in NetBeans 5.0. There is a chance that
GroupLayout will become a part of JDK...