HandlerUtil.getPreferredHandler(Class<H> handlerType, Class<T> type) throws an exception if top-ranked handlers have the same order ranking

This is problematic because PatientValidator and PersonValidator have the same ranking (order = 50).

So if you attempt to fetch the preferred handler for validating a Patient, this exception is thrown.

Probably getPreferredHandler should return the more-specific class. (PatientValidator is this case).