David,
You will probably get away with combo boxes as long as your other design decisions are consistent with it. As far as I can tell by reading this forum, a lot of people have used them.
E.g. you will need to assume that no new records are created or introduce a mechanism that notifies clients if records are added.
(And what to do if records are deleted?)
I have decided to use regular JTextFields for the following reasons:
avoids problems you just mentionedmatches with how people expect to search (compare e.g. searching in web browsers and word processors)combo boxes are very annoying when the number of options is large (>10). Remember those combo boxes where you must select your country? I decided to add an option in my search dialog that allows the user to switch between searching for exact matches and partial matches. I am aware that this won't give me any extra credits, but it adds to the testability of my find() method.
Frans.