I like the idea of the cattle drive, and I was planning to join.
I am a bit surprised that the whole course is still on jdk1.4. I use java6 at work, and I think I would like at least java5 (generics etc ...). Browsing randomly the mailing list, I've seen people been advised to run the compiler with the option for 1.4 to avoid compiler errors. I guess that means that the exercises do cover bits that have changed in more recent versions of java.
Is there any reason not to switch to a more recent version? What is you view on the subject?