code: public static boolean isSuperuser(String username)
      {
          UntypedResultSet result = selectUser(username);
          return !result.isEmpty() && result.one().getBoolean("super");
      }
docs: Checks if the user is a known superuser.
  
  @param username Username to query.
  @return true is the user is a superuser, false if they aren't or don't exist at all.