This week's book giveaway is in the OCMJEA forum. We're giving away four copies of OCM Java EE 6 Enterprise Architect Exam Guide and have Paul Allen & Joseph Bambara on-line! See this thread for details.
That's because the Java classes for the Date used by the session where loaded before the change. Java classes are not hot redeployable, just some application/web servers do redeploys and only in some especific dirs.