The underlying JSoup html validation framework is much more powerful than the current implementation of the SafeHtml Validator allows. Instead of using a fixed enumeration the Whitelist class itself should be provided as an attribute to the validator. Use case:

Providing rich-html content where it is sometimes necessary to float some components/images on the right side next to the text I tried to allow the tag "div" and used the straightforward "additionalTags" attribute just to realize in the next step there is no way I can add the attributes "class" or "style" to it (in general or restricted to "div").

Without those attributes my "div" is useless.