Java could work - Hive account@dez1337 has been working on a java api for steem. I personally don't work with java so I can't speak much more than that or even know if it's good to recommend :)

Other choices would be to use Python or Javascript, both of which have pretty solid libraries for working with the blockchain:

• https://github.com/steemit/steem-js
• https://github.com/steemit/steem-python

Those are the languages I primarily use, as well as a large percent of the developer community here.