JDBC Connection becoming null

I’m developing an application using Java servlets and JDBC. Right now I’m seeing a strange effect where at then end of the servlet process, I call the rollback method on the connection object, but it can’t complete it because the Connection object has become null. The Connection object is stored as a private member variable of the UserStore class. It does have a method that sets it to null, but I have confirmed that it is not being called.

I’m also having a problem where the Connection object is open when it is obtained from the DriverManager, but becomes closed prior to its use in a query.

Can anyone shed any light on what might be causing these effects?

Thanks,

Steve Duran