Run some java periodically on App Engine?

Is there a way to periodically run some code on app engine? I have a form which allows users to upload images, and I do the image upload before the full form submission. There is potential for a user to upload an image, and then never finish the form.

I need to periodical开发者_运维知识库ly run a check and delete any unassociated images to clean up.

My bad. I didn't have the phrasing right on my searches. This is exactly what I wanted.

http://code.google.com/appengine/docs/java/config/cron.html