Library for trading on major exchanges Is there a library which exposes order-book and trading functionality of major exchanges like BTC-e, Bitfinex, Cryptsy etc. ? I know these site have their own API but I wanted to re-use the code, if some sort of library is already available.

I am looking for a java library in particular.
Check out xchange on github::
https://github.com/timmolter/XChange

It works on multiple exchanges, and is written in Java.