public URLNormalizer upperCaseEscapeSequence() {
        if (url.contains("%")) {
            StringBuffer sb = new StringBuffer();
            Matcher m = PATTERN_PERCENT_ENCODED_CHAR.matcher(url);
            while (m.find()) {
                m.appendReplacement(sb, m.group(1).toUpperCase());
            }
            url = m.appendTail(sb).toString();
        }
        return this;
    }
@Test
    public void testUpperCaseEscapeSequence() {
        s = "http://www.example.com/a%c2%b1b";
        t = "http://www.example.com/a%C2%B1b";
        assertEquals(t, n(s).upperCaseEscapeSequence().toString());
    }