jdk6 has been released!

Tonight I occasionally browsed java.sun.com, It was very surprising that J2SE 6 had been available. COOL! Well Done! It was so quickly that sun pushed the newer edition of jdk.
After going through this page, I found there are not too much exciting features in this release except script.
More detail documents can be found in DevX: Mustang Must-Haves: What's Cool in Java SE 6 and Java SE 6's New Scripting and Compiling Goodies .
You can see another cool stuff is compile API. Even there is a project gosling using compile API as a replacement for ANT. It used java as build language other than xml. Also it used some advanced feature such as annotation, compile API.
The questions for gosling are :
1) the build java file need not be compiled?
2) Is it more quickly than old ANT?
3) Why not use script as a language? Though the java maybe be a better choice than XML, it also has a more complex grammar than XML. With XSL XML can be validated easily. If the java don't be compiled in eclipse, how can I make sure my java is correct? till the run-time? How about script? maybe it is more appropriate.