Java Development Tools

I'm using Oracle Enterprise Pack for Eclipse and WLS 10.3.3. I'm trying to write a web service to do a simple Oracle database query using JDBC and then return the results. I'm attempting to return the result in an array. Each element of the array contains an instance of a custom class that I wrote to hold one row of the results. When I try to publish the web service I get an error "javax.xml.ws.WebServiceException: Unable to create JAXBContext".

If I change the return type of the web service to a simpler type, such as String, then I can publish it with no problem.

Is there something special I need to do when returning a complex class type, such as placing some annotations in the code?

Thank you!
Neal