Sqoop2: Refactor validations

On my quest to fix technical depth that I've myself put into Sqoop2, I would like to propose refactoring validator interface. The problems that I see:

• Validations are ONLY server side, client has to always go to the sever to validate everything. Whereas some validations can never be executed to client, it would be nice to give client opportunity to run at least some basic validations.
• Validations are in separate Validator class and are completely separate from the actual configuration objects. This makes the development quite hard and "disconnected".
• Entire interface is very non-intuitive as one has to call methods where parameters are names of instance variables which is awful and don't provide any level of checking that you've set validation on the correct object.

I would like to move the validations to annotations so that validation and given configuration object are in the same place. This will also allow us to serialize and send them to the client.