Java Utililty Methods Hour Format

if (date == null)
    return null;
String str_date = null;
if (format != null) {
    DateFormat formater = new SimpleDateFormat(format);
    str_date = formater.format(date);
} else {
    str_date = datefmt.format(date);
...

return date != null && format != null ? new SimpleDateFormat(format).format(date) : null;

SimpleDateFormat sdf = new SimpleDateFormat(format, locale);
return sdf.format(date);

try {
    SimpleDateFormat sdf = new SimpleDateFormat(patter);
    return sdf.format(date);
} catch (RuntimeException e) {
    return "";

if (date == null)
    return "";
Calendar calendar = Calendar.getInstance();
calendar.setTime(date);
return formatCalendar(calendar, pattern);

SimpleDateFormat formatter = new SimpleDateFormat(pattern, Locale.US);
formatter.setTimeZone(GMT);
return formatter.format(date);

SimpleDateFormat sdf = getDateFormatter(timeFormat);
TimeZone ltz = TimeZone.getDefault();
Date nd = date;
TimeZone tz = TimeZone.getTimeZone(timeZone);
if (ltz.hasSameRules(tz) == false) {
    long lo = ltz.getRawOffset();
    long to = tz.getRawOffset();
    nd = new Date(date.getTime() - lo + to);
...

ISO8601_FORMAT_OUT.format(date, buffer, new FieldPosition(0));

SimpleDateFormat sdf = new SimpleDateFormat(DATE_PATTERN);
if (tz != null) {
    sdf.setTimeZone(tz);
return sdf.format(date);

try {
    SimpleDateFormat sdf = new SimpleDateFormat();
    sdf.applyPattern("yyyy-MM-dd HH:mm:ss");
    return sdf.format(dateString);
} catch (Exception e) {
    e.printStackTrace();
return "";
...