Ask HN: Who's doing Java and what skills do they have?

I am at core a Ruby programmer, other than that I have wide horisons. I have been asked recently to warp my mind into java "enterprise" projects for document management (Alfresco anyone?) business inteligence and so on. The worst puddle untill now has been transparency (compared to ruby's readme driven development). By transparency I mean accesing knowledge on issues that seem best practices (say Spring) is hidden behind a gruesome "complete to access the docs" forms, information pourposely hidden and twisted to urge you "buy the enterprise version", "buy support" and so on.. One alfresco book I've read is half about "what a good and pro DM I have on front of me" and the other half only manages to scratch the concepts I'd like to know about.

This is my attempt to gain some inside knowledge and evaluate my competences on the matter.

1. Are you doing (server side) java?

2. What java skills do you have? How did you learned them? What (java topic) would you want to learn further?

3. On what (enterprise) context tho you use theese skils (DM, ERP, EIS etc)? How big is your team?

4. Do you think another platform whould make the above (3) easyer?