What libraries should I use for E-Commerce We are developing some automated payment functions for Bitcoin. We want to automate transactions via a backend server setup; what libraries would be best suited?

I've found two libraries so far:


Java has BitcoinJ
C++ has bitcoin-qt 


Would a thin or selfish client suffice ?

Do they support QR codes ?

P.S. I would prefer a Java over C++ coming from a C# background.
I developed a solution using bitcoind (bitcoin-qt).

It was very easy with PHP + RPC Class, but bitcoind has some limitations which make it not very suited as a backend/library.