There's a simple but effective "hack" for doing this which will work provided you have access to a UNIX server somewhere which you can set up cron jobs on. Have a daily (or weekly) cron task that does this:
lynx -dump
http://yoursite.com/your/servlet > /dev/null
This will then cause the Lynx browser "access" your servlet at a set time every day, dumping the output HTML to /dev/null. It's not a very elegant solution but it works