How to use

DateFormat

in

java.text

public boolean isDateExpired(String input, Date expiration) throws ParseException {
 DateFormat dateFormat = new SimpleDateFormat ("dd/MM/yyyy");
 Date date = dateFormat.parse(input);
 return date.after(expiration);
}

private static String clientDateString() {
  TimeZone tz = TimeZone.getTimeZone("UTC");
  DateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm'Z'");
  df.setTimeZone(tz); // strip timezone
  return df.format(new Date());
}

 String dt = "2008-01-01";  // Start date
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
Calendar c = Calendar.getInstance();
c.setTime(sdf.parse(dt));
c.add(Calendar.DATE, 1);  // number of days to add
dt = sdf.format(c.getTime());  // dt is now the new date

 String currentDateTimeString = DateFormat.getDateTimeInstance().format(new Date());

// textView is the TextView view that should display it
textView.setText(currentDateTimeString);

 @Override protected DateFormat initialValue() {
  // Date format specified by RFC 7231 section 7.1.1.1.
  DateFormat rfc1123 = new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss 'GMT'", Locale.US);
  rfc1123.setLenient(false);
  rfc1123.setTimeZone(UTC);
  return rfc1123;
 }
};

   /**
    * @{inheritDoc}
    */
 public Date parse(String source, ParsePosition pos) {
   dateFormat.setTimeZone(TimeZone.getDefault());
   return dateFormat.parse(source, pos);
 }
}

  /**
   * @{inheritDoc}
   */
public StringBuffer format(Date date, StringBuffer toAppendTo, FieldPosition fieldPosition) {
  dateFormat.setTimeZone(TimeZone.getDefault());
  return dateFormat.format(date, toAppendTo, fieldPosition);
}

try {
  final TimeZone denverZone = TimeZone.getTimeZone("America/Denver");
  TimeZone.setDefault(denverZone);
  final DateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS XXX");
  format.setTimeZone(denverZone);
  final Date oct31_01MDT = new Date(1099206000000L);
  final Date oct31MDT = new Date(oct31_01MDT.getTime() - 3600000L); // - 1 hour
  final Date oct31_01_02MDT = new Date(oct31_01MDT.getTime() + 120000L);  // + 2 minutes
  final Date oct31_01_02_03MDT = new Date(oct31_01_02MDT.getTime() + 3000L);    // + 3 seconds
  final Date oct31_01_02_03_04MDT = new Date(oct31_01_02_03MDT.getTime() + 4L);       // + 4 milliseconds
  assertEquals("Check 00:00:00.000", "2004-10-31 00:00:00.000 -06:00", format.format(oct31MDT));
  assertEquals("Check 01:00:00.000", "2004-10-31 01:00:00.000 -06:00", format.format(oct31_01MDT));
  assertEquals("Check 01:02:00.000", "2004-10-31 01:02:00.000 -06:00", format.format(oct31_01_02MDT));
  assertEquals("Check 01:02:03.000", "2004-10-31 01:02:03.000 -06:00", format.format(oct31_01_02_03MDT));
  assertEquals("Check 01:02:03.004", "2004-10-31 01:02:03.004 -06:00", format.format(oct31_01_02_03_04MDT));
  final Calendar gval = Calendar.getInstance();
  gval.setTime(new Date(oct31_01MDT.getTime()));
  gval.set(Calendar.MINUTE, gval.get(Calendar.MINUTE)); // set minutes to the same value
  assertEquals("Demonstrate Problem", gval.getTime().getTime(), oct31_01MDT.getTime() + 3600000L);
} finally {
  TimeZone.setDefault(defaultZone);

 Calendar c = Calendar.getInstance();
c.setTime(new Date(yourmilliseconds));
c.set(Calendar.MILLISECOND, 0);
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm.ss.SSS'Z'");
sdf.setTimeZone(TimeZone.getTimeZone("GMT"));
System.out.println(sdf.format(c.getTime()));

 Date now = new Date(); // java.util.Date, NOT java.sql.Date or java.sql.Timestamp!
String format1 = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS", Locale.ENGLISH).format(now);
String format2 = new SimpleDateFormat("EEE, d MMM yyyy HH:mm:ss Z", Locale.ENGLISH).format(now);
String format3 = new SimpleDateFormat("yyyyMMddHHmmss", Locale.ENGLISH).format(now);

System.out.println(format1);
System.out.println(format2);
System.out.println(format3);

UTC = TimeZone.getTimeZone("UTC");
TimeZone.setDefault(UTC);
final Calendar c = new GregorianCalendar(UTC);
c.set(1, 0, 1, 0, 0, 0);
c.set(Calendar.MILLISECOND, 0);
BEGINNING_OF_TIME = c.getTime();
c.setTime(new Date(Long.MAX_VALUE));
END_OF_TIME = c.getTime();
final SimpleDateFormat sdf = new SimpleDateFormat(ISO_8601_24H_FULL_FORMAT);
sdf.setTimeZone(UTC);
System.out.println("sdf.format(BEGINNING_OF_TIME) = " + sdf.format(BEGINNING_OF_TIME));
System.out.println("sdf.format(END_OF_TIME) = " + sdf.format(END_OF_TIME));
System.out.println("sdf.format(new Date()) = " + sdf.format(new Date()));
System.out.println("sdf.parse(\"2015-04-28T14:23:38.521Z\") = " + sdf.parse("2015-04-28T14:23:38.521Z"));
System.out.println("sdf.parse(\"0001-01-01T00:00:00.000Z\") = " + sdf.parse("0001-01-01T00:00:00.000Z"));
System.out.println("sdf.parse(\"292278994-08-17T07:12:55.807Z\") = " + sdf.parse("292278994-08-17T07:12:55.807Z"));

 final DateFormat format = new SimpleDateFormat("E. M/d");
final String dateStr = "Thu. 03/01";
final Date date = format.parse(dateStr);

GregorianCalendar gregory = new GregorianCalendar();
gregory.setTime(date);

XMLGregorianCalendar calendar = DatatypeFactory.newInstance()
    .newXMLGregorianCalendar(
      gregory);

 TimeZone timeZone = TimeZone.getTimeZone("UTC");
Calendar calendar = Calendar.getInstance(timeZone);
SimpleDateFormat simpleDateFormat = 
    new SimpleDateFormat("EE MMM dd HH:mm:ss zzz yyyy", Locale.US);
simpleDateFormat.setTimeZone(timeZone);

System.out.println("Time zone: " + timeZone.getID());
System.out.println("default time zone: " + TimeZone.getDefault().getID());
System.out.println();

System.out.println("UTC:     " + simpleDateFormat.format(calendar.getTime()));
System.out.println("Default: " + calendar.getTime());

 SimpleDateFormat isoFormat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss");
isoFormat.setTimeZone(TimeZone.getTimeZone("UTC"));
Date date = isoFormat.parse("2010-05-23T09:01:02");

 Calendar cal = Calendar.getInstance();
SimpleDateFormat sdf = new SimpleDateFormat("EEE MMM dd HH:mm:ss z yyyy", Locale.ENGLISH);
cal.setTime(sdf.parse("Mon Mar 14 16:02:37 GMT 2011"));// all done

 TimeZone zone = TimeZone.getTimeZone("America/New_York");
DateFormat format = DateFormat.getDateTimeInstance();
format.setTimeZone(zone);

System.out.println(format.format(new Date()));

 Calendar start = Calendar.getInstance();
Calendar end = Calendar.getInstance();
start.set(2010, 7, 23);
end.set(2010, 8, 26);
Date startDate = start.getTime();
Date endDate = end.getTime();
long startTime = startDate.getTime();
long endTime = endDate.getTime();
long diffTime = endTime - startTime;
long diffDays = diffTime / (1000 * 60 * 60 * 24);
DateFormat dateFormat = DateFormat.getDateInstance();
System.out.println("The difference between "+
 dateFormat.format(startDate)+" and "+
 dateFormat.format(endDate)+" is "+
 diffDays+" days.");

 Long gmtTime =1317951113613L; // 2.32pm NZDT
Long timezoneAlteredTime = 0L;

if (offset != 0L) {
  int multiplier = (offset*60)*(60*1000);
  timezoneAlteredTime = gmtTime + multiplier;
} else {
  timezoneAlteredTime = gmtTime;
}

Calendar calendar = new GregorianCalendar();
calendar.setTimeInMillis(timezoneAlteredTime);

DateFormat formatter = new SimpleDateFormat("dd MMM yyyy HH:mm:ss z");

formatter.setCalendar(calendar);
formatter.setTimeZone(TimeZone.getTimeZone(timeZone));

String newZealandTime = formatter.format(calendar.getTime());

private String formatDate(long date) {
  return newDateFormat().format(new Date(date));
}

  private static String time(long t) {
    DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss", Locale.ROOT);
    Calendar cal = Calendar.getInstance(TimeZone.getDefault(), Locale.ROOT);
    cal.setTimeInMillis(t);
    return dateFormat.format(cal.getTime());
  }
}