code: public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException, DataAccessException {
          return getSecurityComponents().userDetails.loadUserByUsername(username);
      }
docs: Shortcut for {@link UserDetailsService#loadUserByUsername(String)}.
  
  @throws UserMayOrMayNotExistException
  If the security realm cannot even tell if the user exists or not.
  @return
  never null.