The end result you want is certainly possible, but that description is not how our service works. You should start out in the web app getting used to how things like templates, lists, and campaigns interact using our getting started articles:
http://kb.mailchimp.com/search/results/?q=getting+startedOnce you've done that and are comfortable, you can come back to the API to automate things. The API doesn't care what language your using - the methods still work the same. We do have links to some 3rd party wrappers that happen to be made for Java in the downloads area:
http://apidocs.mailchimp.com/api/downloads/#javajesse