I have used JOGL in the past to create some cool-looking Swing demos. OpenGL is a fine API but it lacks helper tools. Fortunately for us developers, the guys behind JOGL wrote a few helper classes. They let you manage textures and display text very easily.
Chris Campbell, from the Java 2D team, has a demo and some information regarding those classes. I am particularly fond of the
TextureRenderer class which lets you use Java 2D to draw into an OpenGL texture. Chris’ demo is a good example of what you can do with it.
Java SE 6 and JOGL are a killer combo to create filthy rich clients :)