Java Utililty Methods Date Format ISO

return formatISO8601(new Date());

if (date == null) {
    return null;
Calendar cal = GregorianCalendar.getInstance();
cal.setTime(date);
cal.setTimeZone(TimeZone.getTimeZone("UTC"));
return DatatypeConverter.printDateTime(cal);

SimpleDateFormat formatter = createIso8601Format();
formatter.setTimeZone(UTC);
return formatter.format(date);

if (date == null)
    return "";
String str = format(date, getIso8601DateFormat());
StringBuffer sb = new StringBuffer();
sb.append(str.substring(0, str.length() - 2));
sb.append(":");
sb.append(str.substring(str.length() - 2));
return sb.toString();
...

return format(date, "yyyy-MM-dd'T'HH:mm:ss.SSS");

SimpleDateFormat simpleDateFormat = new SimpleDateFormat(ISO8601_TS_FORMAT);
return simpleDateFormat.format(date);

SimpleDateFormat df = null;
if (timeZone != null) {
    df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'.'SSSZ");
    df.setTimeZone(timeZone);
    String result = df.format(date);
    if (result.endsWith("0000"))
        return result.replaceAll("[+-]0000$", "Z");
    return result.replaceAll("(\\d{2})(\\d{2})$", "$1:$2");
...

if (date == null)
    return "";
SimpleDateFormat dateFormat = new SimpleDateFormat(ISO8601_DATE_FORMAT_PATTERN);
return dateFormat.format(date);

Calendar cal = Calendar.getInstance();
cal.setTime(Preconditions.checkNotNull(date, "Date can not be null."));
return DatatypeConverter.printDateTime(cal);

String result;
outCal.setTime(d);
if (outCal.get(Calendar.MILLISECOND) == 0) {
    result = outFmtSecond.format(d);
} else {
    result = outFmtMillisec.format(d);
int rl = result.length();
...