You are not getting an SQLException anywhere? As you doubtless already know, NullPointerExceptions (NPEs) are very common and very annoying. I seem to write about them all the time, most recently here (note there is a mistake which I picked up later).
Are you sure your connection isn't null?
I presume the SQL is correct; it looks all right, and it would produce an SQLException rather than an NPE.
Go through what I wrote, and add a line just before where you get your Exception which prints whether the connection is null. See whether that helps.
I probably can't help any more now; it is too late, but there will be other people around.
Joined: Nov 30, 2008
Thanks very much for that. The null connection was the problem.
Joined: Oct 13, 2005
You're welcome. It was easy to guess from the info you provided.
subject: NullPointerException on PreparedStatement