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 testExtractLinksNone() {
        List<String> links = null;

        links = RegexUtils.extractLinks(null);
        assertNotNull(links);
        assertEquals(0, links.size());

        links = RegexUtils.extractLinks("");
        assertNotNull(links);
        assertEquals(0, links.size());

        links = RegexUtils.extractLinks("Test with no links " + "What about www.google.com");
        assertNotNull(links);
        assertEquals(0, links.size());
    }