com.mongodb.DB.authenticate(username, password) fails often when invoked from multiple threads. Mongod console logs "auth: bad nonce received or getnonce not called. could be a driver bug or a security attack" whenever authentication fails.

Expected result:
authenticate method should return consistent results.

Steps to reproduce:
import https://gist.github.com/2882362 to your workspace and run or download the attached sample project, import it to your favourite IDE and run.

Additional information:
http://forum.springsource.org/showthread.php?127153-CannotGetMongoDbConnectionException-in-a-multithreaded-environment