I have been checking out Groovy a bit and I feel that moving a Java program to Groovy little by little -- grabbing a class and making it a Groovy class, then converting the method guts a bit at a time -- might be a relatively sane way to take advantage of some of the Groovy language features. I would also do new classes in Groovy.

Questions:

1. Is this a reasonable way to convert?
2. Can I keep all of my public methods and and fields in Java? Groovy is "just" a superset, right?
3. What kinds of things would you not do in Groovy, but prefer Java instead?