port org.jsoup.Jsoup;


String html = "bfbvfvbrbvb <div id='adressscroll'> G74 4GX</div>";

Pattern pattern = Pattern.compile("[A-Z]{1,2}[0-9][0-9A-Z]?\s?[0-9][A-Z]{2}");

Document doc = Jsoup.parse(html);

Element address = doc.select("div.adressscroll").first();
String divString = address.html();

Matcher matcher = pattern.matcher(davString);
if (matcher.find()){
    System.out.println(matcher.group(1));
}