This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
I would try writing a separate class to connect to your database, using the same JDBC driver, username, password and driver URL that you are currently using - see if it connects to your database. That way you can isolate the connection and ascertain whether it's to do with WLS or not.