Java Utililty Methods Millisecond Convert

Long ret = null;
DateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
formatter.setTimeZone(TimeZone.getTimeZone("UTC"));
Date date;
try {
    date = (Date) formatter.parse(dateString);
    DateTime dt = new DateTime(date);
    ret = dt.getMillis();
...

return convertStrToDate(dateStr, "yyyy-MM-dd HH:mm:ss").getTime();

try {
    DateFormat dateFormat = new SimpleDateFormat("yy-MM-dd HH:mm:ss");
    DateFormat dayFormat = new SimpleDateFormat("yy-MM-dd");
    Date curDate = dateFormat.parse(dayFormat.format(new Date()) + " " + time);
    return curDate.getTime();
} catch (ParseException e) {
    e.printStackTrace();
return 0;

SimpleDateFormat dformat = new SimpleDateFormat("YYYY:MM:dd:HH:mm:ss:SS");
Date d = new Date(milliseconds);
String dstr = dformat.format(d);
return dstr;

return new SimpleDateFormat("yyyyMMddhhmmssSSS", locale).format(new Date());

long minutes = TimeUnit.MILLISECONDS.toMinutes(millis)
        - TimeUnit.HOURS.toMinutes(TimeUnit.MILLISECONDS.toHours(millis));
long hours = TimeUnit.MILLISECONDS.toHours(millis);
StringBuilder b = new StringBuilder();
b.append(hours == 0 ? "" : String.valueOf(hours) + "h");
b.append(minutes == 0 ? "" : String.valueOf(minutes) + "m");
long seconds = millis - TimeUnit.MINUTES.toMillis(TimeUnit.MILLISECONDS.toMinutes(millis));
b.append(secondFormat.format(seconds / 1000.0) + "s");
...

Date date = new Date(millis);
return sdf.format(date);

Calendar calendar = Calendar.getInstance();
calendar.setTimeInMillis(timelnMillis);
Date date = calendar.getTime();
SimpleDateFormat f = new SimpleDateFormat("yyyy-MM-dd");
String newTypeDate = f.format(date);
return newTypeDate;

String result = "0";
if (timeTakenMillis > 0) {
    float timeSeconds = timeTakenMillis / 1000f;
    result = getSecondsFormatter().format(timeSeconds);
return result;

DateFormat formatterTimeGMT = new SimpleDateFormat(TIME_FORMAT);
formatterTimeGMT.setTimeZone(TimeZone.getTimeZone(TIME_ZONE_GMT));
Date date = new Date();
date.setTime(milliseconds);
String timeString = formatterTimeGMT.format(date);
return timeString;