Automated Testing for Oracle APEX Web Application

I'm currently working on a new web application and it's being developed using Oracle APEX. It's basically a ten page wizard-style web form that gets filled out and submitted. In nearly all cases, only three or four of these pages will be used and the other exist to present special-case information to the user. Anyway... I'm currently writing a test plan to ensure all the validation and processes are working as expected and I would like to try automating this testing if at all possible. Does anyone know any good automated testing tools (preferable open source) that I can put to use for this purpose? Also, as it might be relevant, I'm limited to Java and/or APEX for tailoring these tools to meet my testing needs.