public static  void append(StringBuilder sb,
    Iterator contents,
    String separator) 
{
        boolean isFirst = true;
        while (contents.hasNext()) {
            if (!isFirst) {
                sb.append(separator);
            }
            sb.append(contents.next());
            isFirst = false;
        }
}

To the given string builder, appends all strings in the given iterator, separating them with the given separator. For example, for an interator "a" "b" "c" and separator ":" the output is "a:b:c".

 public static String getLastComponent(String s) 
{
        if (s == null) {
            return null;
        }
        int lastDot = s.lastIndexOf(".");
        if (lastDot == -1) {
            return s;
        } else {
            return s.substring(lastDot + 1);
        }
}

 public static boolean isEmpty(String s) 
{
        return s == null || "".equals(s);
}