string_int_pair to_string_int_pair() {
        if (!String.class.equals(first.getClass()) || !Integer.class.equals(second.getClass())) {
            throw new IllegalArgumentException("Incompatible types");
        }

        return new string_int_pair((String) first, (Integer) second);
    }
string_int_pair to_string_int_pair ( ) { if ( ! String . class . equals ( first . getClass ( ) ) || ! Integer . class . equals ( second . getClass ( ) ) ) { throw new IllegalArgumentException ( "Incompatible types" ) ; } return new string_int_pair ( ( String ) first , ( Integer ) second ) ; }
@return a native object