How to use

TimeZone

in

java.util

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());
}

 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());

private Timestamp convertToTimestamp(Object object) {
  final long millis;
  if (object instanceof Long) {
    millis = (Long) object;
  } else {
    // use 'provided' Joda time
    final DateTime value = (DateTime) object;
    millis = value.toDate().getTime();
  }
  return new Timestamp(millis - LOCAL_TZ.getOffset(millis));
}

 import java.util.TimeZone;

public class Test {
  public static void main(String[] args) throws Exception {
    long startOf1900Utc = -2208988800000L;
    for (String id : TimeZone.getAvailableIDs()) {
      TimeZone zone = TimeZone.getTimeZone(id);
      if (zone.getRawOffset() != zone.getOffset(startOf1900Utc - 1)) {
        System.out.println(id);
      }
    }
  }
}

/**
 * Parse the given {@code timeZoneString} value into a {@link TimeZone}.
 * @param timeZoneString the time zone {@code String}, following {@link TimeZone#getTimeZone(String)}
 * but throwing {@link IllegalArgumentException} in case of an invalid time zone specification
 * @return a corresponding {@link TimeZone} instance
 * @throws IllegalArgumentException in case of an invalid time zone specification
 */
public static TimeZone parseTimeZoneString(String timeZoneString) {
  TimeZone timeZone = TimeZone.getTimeZone(timeZoneString);
  if ("GMT".equals(timeZone.getID()) && !timeZoneString.startsWith("GMT")) {
    // We don't want that GMT fallback...
    throw new IllegalArgumentException("Invalid time zone specification '" + timeZoneString + "'");
  }
  return timeZone;
}

@Config("hive.time-zone")
public HiveClientConfig setTimeZone(String id)
{
  this.timeZone = (id != null) ? id : TimeZone.getDefault().getID();
  return this;
}

public final String formatUTCTZ(Date date) {
  SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'");
  sdf.setTimeZone(TimeZone.getTimeZone("UTC"));
  return sdf.format(date);
}

static String timeAsGmt() {
 SimpleDateFormat sdf = new SimpleDateFormat();
 sdf.setTimeZone(TimeZone.getTimeZone("GMT"));
 sdf.applyPattern("dd MMM yyyy HH:mm:ss z");
 return sdf.format(Calendar.getInstance().getTime());
}

 String getServerTime() {
  Calendar calendar = Calendar.getInstance();
  SimpleDateFormat dateFormat = new SimpleDateFormat(
    "EEE, dd MMM yyyy HH:mm:ss z", Locale.US);
  dateFormat.setTimeZone(TimeZone.getTimeZone("GMT"));
  return dateFormat.format(calendar.getTime());
}

 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()));

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"));

public static Long toEpoch(Date dateTime, String timeZone) {
 // Epoch of midnight in local time zone
 Calendar timeOffset = Calendar.getInstance(TimeZone.getTimeZone(timeZone));
 timeOffset.set(Calendar.MILLISECOND, 0);
 timeOffset.set(Calendar.SECOND, 0);
 timeOffset.set(Calendar.MINUTE, 0);
 timeOffset.set(Calendar.HOUR_OF_DAY, 0);
 long midnightOffSet = timeOffset.getTime().getTime();
 long localTimestamp = dateTime.getTime();
 return timeOffset == null ? null : midnightOffSet + localTimestamp;
}

/**
 * Sets the Date and Cache headers for the HTTP Response
 *
 * @param response    HTTP response
 * @param fileToCache file to extract content type
 */
private static void setDateAndCacheHeaders(HttpResponse response, File fileToCache) {
 SimpleDateFormat dateFormatter = new SimpleDateFormat(HTTP_DATE_FORMAT, Locale.US);
 dateFormatter.setTimeZone(TimeZone.getTimeZone(HTTP_DATE_GMT_TIMEZONE));
 // Date header
 Calendar time = new GregorianCalendar();
 response.headers().set(DATE, dateFormatter.format(time.getTime()));
 // Add cache headers
 time.add(Calendar.SECOND, HTTP_CACHE_SECONDS);
 response.headers().set(EXPIRES, dateFormatter.format(time.getTime()));
 response.headers().set(CACHE_CONTROL, "private, max-age=" + HTTP_CACHE_SECONDS);
 response.headers().set(
     LAST_MODIFIED, dateFormatter.format(new Date(fileToCache.lastModified())));
}

/**
 * Sets the Date header for the HTTP response
 *
 * @param response
 *            HTTP response
 */
private static void setDateHeader(FullHttpResponse response) {
  SimpleDateFormat dateFormatter = new SimpleDateFormat(HTTP_DATE_FORMAT, Locale.US);
  dateFormatter.setTimeZone(TimeZone.getTimeZone(HTTP_DATE_GMT_TIMEZONE));
  Calendar time = new GregorianCalendar();
  response.headers().set(DATE, dateFormatter.format(time.getTime()));
}

 @Override
 public Date deserialize(JsonParser p, DeserializationContext ctxt) throws IOException {
  final String dateTimeInUnixFormat = p.getText();
  try {
   Calendar calendar = Calendar.getInstance(TimeZone.getTimeZone("UTC"));
   calendar.setTimeInMillis(Long.parseLong(dateTimeInUnixFormat + "000"));
   return calendar.getTime();
  } catch (Exception e) {
   return new Date(0);
  }
 }
}

 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 c = Calendar.getInstance();
 System.out.println("current: "+c.getTime());
 TimeZone z = c.getTimeZone();
 int offset = z.getRawOffset();
 if(z.inDaylightTime(new Date())){
   offset = offset + z.getDSTSavings();
 }
 int offsetHrs = offset / 1000 / 60 / 60;
 int offsetMins = offset / 1000 / 60 % 60;
 System.out.println("offset: " + offsetHrs);
 System.out.println("offset: " + offsetMins);
 c.add(Calendar.HOUR_OF_DAY, (-offsetHrs));
 c.add(Calendar.MINUTE, (-offsetMins));
 System.out.println("GMT Time: "+c.getTime());

 private Date newDate(int year, int month, int day, int hour, int offset) {
  Calendar calendar = new GregorianCalendar(TimeZone.getTimeZone("GMT"));
  calendar.set(year, month - 1, day, hour, 0, 0);
  calendar.set(Calendar.MILLISECOND, 0);
  return new Date(calendar.getTimeInMillis() - TimeUnit.HOURS.toMillis(offset));
 }
}

@Test
public void testFormat() {
  final Calendar c = Calendar.getInstance(FastTimeZone.getGmtTimeZone());
  c.set(2005, Calendar.JANUARY, 1, 12, 0, 0);
  c.setTimeZone(TimeZone.getDefault());
  final StringBuilder buffer = new StringBuilder ();
  final int year = c.get(Calendar.YEAR);
  final int month = c.get(Calendar.MONTH) + 1;
  final int day = c.get(Calendar.DAY_OF_MONTH);
  final int hour = c.get(Calendar.HOUR_OF_DAY);
  buffer.append (year);
  buffer.append(month);
  buffer.append(day);
  buffer.append(hour);
  assertEquals(buffer.toString(), DateFormatUtils.format(c.getTime(), "yyyyMdH"));
  assertEquals(buffer.toString(), DateFormatUtils.format(c.getTime().getTime(), "yyyyMdH"));
  assertEquals(buffer.toString(), DateFormatUtils.format(c.getTime(), "yyyyMdH", Locale.US));
  assertEquals(buffer.toString(), DateFormatUtils.format(c.getTime().getTime(), "yyyyMdH", Locale.US));
}

 Calendar cSchedStartCal = Calendar.getInstance(TimeZone.getTimeZone("GMT"));
long gmtTime = cSchedStartCal.getTime().getTime();

long timezoneAlteredTime = gmtTime + TimeZone.getTimeZone("Asia/Calcutta").getRawOffset();
Calendar cSchedStartCal1 = Calendar.getInstance(TimeZone.getTimeZone("Asia/Calcutta"));
cSchedStartCal1.setTimeInMillis(timezoneAlteredTime);