F3 is actually a declarative Java scripting language with static typing for good IDE support and compile-time error reporting (unlike JavaScript...), type-inference, declarative syntax, and automatic data-binding with full support for 2d graphics and standard Swing components as well as declarative animation. You can also import java classes, create new Java objects, call their methods, and implement Java interfaces.The blog of the lead developer is available here. This looks like another interesting Java project, which is developed by Sun, so it will be open-sourced very soon.
There are lots of demos available on the blog, so you can see the work first-hand. It kind of reminds me of Win32GUI Generics. It looks pretty interesting and something new for Java, so it would be something to keep an eye on.
