Thank you all
Indeed, I need to know a list of all user classes with the specified name, at runtime. For example, for "List" it wold return "java.util.List", "java.awt.List" and so on, if those were classes in the web-inf\classes dir. Then, by reflection, I wold know wich one I should use.
A workaround I've just discovered for that, for a while, is running through servletContext.getResourcePaths("/WEB-INF/classes/"), recursively, and "catalogging" all ".class" found, replacing "/" whith "." to know its packages.
I'm just wondering there wasn't a simplier (less ugly) way to do that...
Thank you all, again