public static String deleteWhitespace(String str)
    {
        if (isEmpty(str))
        {
            return str;
        }
        int sz = str.length();
        char[] chs = new char[sz];
        int count = 0;
        for (int i = 0; i < sz; i++)
        {
            if (!Character.isWhitespace(str.charAt(i)))
            {
                chs[count++] = str.charAt(i);
            }
        }
        if (count == sz)
        {
            return str;
        }
        return new String(chs, 0, count);
    }