Today, Ryan Lubke committed code to the Mojarra tree that will allow a JSF developer to prototype and/or develop just about every JSF artifact using Groovy. When deployed to the server in development mode, the Groovy file can be changed on disk, and the changes will be picked up automatically, allowing one to avoid the compile/package/deploy cycle that can make Java web development so tedious. Once the artifact is "done," the Groovy source can be copied to a Java source file and compiled (or the build process can compile the .groovy files to .class files) for production deployment. This could be a really nice feature for component development, for example.
For more details, including a sample NetBeans project, visit Ryan’s entry.
All around, a very, very cool enhancement. Great work, Ryan!