public static List<String> extractLinks(String content) {
        if (content == null || content.length() == 0) {
            return Collections.emptyList();
        }

        List<String> extractions = new ArrayList<>();
        final Matcher matcher = LINKS_PATTERN.matcher(content);
        while (matcher.find()) {
            extractions.add(matcher.group());
        }
        return extractions;

    }
@Test
    public void testExtractLinksFtp() {
        List<String> links = RegexUtils.extractLinks("Test with ftp://www.nutch.org is it found? " +
                "What about www.google.com at ftp://www.google.de");

        assertTrue(links.size() == 2, "Url not found!");
        assertEquals("ftp://www.nutch.org", links.get(0), "Wrong URL");
        assertEquals("ftp://www.google.de", links.get(1), "Wrong URL");
    }