java security classloader

I am implementing a service which uses a URLClassloader to load classes dynamically.

In the interest of security I would like t开发者_StackOverflow中文版o restrict the access of loaded classes. eg no network, file or db access etc.

Anybody got any good resources or tutorials on the web for this kind of thing?

Google for "JavaSeal". But they didn't publish the code though.

http://java.sun.com/developer/technicalArticles/Networking/classloaders/ might be useful