Get Date Object In UTC format in Java

Question

I have written following code  I want to get Date object in UTC format    I am able to get expected date string in UTC using SimpleDateFormat  But using same SimpleDateFormat object  I am not able to get object in UTC format  It is returning object with IST format   After searching  I found that Date object doesn t store timestamp info    How can I get date object in UTC format    import java text DateFormat  import java text ParseException  import java text SimpleDateFormat  import java util Date  import java util TimeZone   public class dddd                    param args             public static void main String   args            System out println  Input -   1393572325000L           DateFormat formatter   new SimpleDateFormat  yyyy-MM-dd HH mm ss            formatter setTimeZone TimeZone getTimeZone  UTC             Date date  new Date 1393572325000L             String dateString   formatter format date            System out println  Converted UTC TIME  using Format method      dateString            Date date2  null          try               date2   formatter parse dateString             catch  ParseException e                e printStackTrace                        System out println  Parsed Date Object  using Parse method      date2            System out println  Expected Date Object   Fri Feb 28 07 25 25 UTC 2014                This prints following output    Input - 1393572325000 Converted UTC TIME  using Format method    2014-02-28 07 25 25 Parsed Date Object  using Parse method    Fri Feb 28 12 55 25 IST 2014 Expected Date Object   Fri Feb 28 07 25 25 UTC 2014

User · Answer

In java 8   It s really easy to get timestamp in UTC by using java 8 java time Instant library    Instant now      That few word of code will return the UTC Timestamp

User · Answer

You can subtract the time zone difference from now   final Calendar calendar    Calendar getInstance    final int      utcOffset   calendar get Calendar ZONE OFFSET    calendar get Calendar DST OFFSET   final long     tempDate    new Date   getTime     return new Date tempDate - utcOffset

User · Answer

A Date doesn t have any time zone  What you re seeing is only the formatting of the date by the Date toString   method  which uses your local timezone  always  to transform the timezone-agnostic date into a String that you can understand    If you want to display the timezone-agnostic date as a string using the UTC timezone  then use a SimpleDateFormat with the UTC timezone  as you re already doing in your question    In other terms  the timezone is not a property of the date  It s a property of the format used to transform the date into a string

User · Answer

final Date currentTime   new Date    final SimpleDateFormat sdf   new SimpleDateFormat  EEE  MMM d  yyyy hh mm ss a z    sdf setTimeZone TimeZone getTimeZone  UTC     System out println  UTC time      sdf format currentTime

User · Answer

tl dr  Instant ofEpochMilli   1 393 572 325 000L           toString        2014-02-28T07 25 25Z   Details   a  You seem be confused as to what a Date is  As the answer by JB Nizet said  a Date tracks the number of milliseconds since the Unix epoch  first moment of 1970  in the UTC time zone  that is  with no time zone offset   So a Date has no time zone     And it has no  format   We create string representations from a Date s value  but the Date itself is not a String and has no String    b  You refer to a  UTC format   UTC is not a format  not I have heard of  UTC  Coordinated Universal Time  is the origin point of time zones  Time zones east of the Royal Observatory in Greenwich  London are some number of hours  amp  minutes ahead of UTC  Westward time zones are behind UTC   You seem to be referring to ISO 8601 formatted strings  You are using the optional format  omitting  1  the T from the middle  and  2  the offset-from-UTC at the end  Unless presenting the string to a user in the user interface of your app  I suggest you generally stick with the usual format     2014-02-27T23 03 14 05 30  2014-02-27T23 03 14Z   Z  for Zulu  or UTC  with an offset of  00 00     c  Avoid the 3 or 4 letter time zone codes  They are neither standardized nor unique   IST  for example can mean either Indian Standard Time or Irish Standard Time    d  Put some effort into searching StackOverflow before posting  You would have found all your answers    e  Avoid the java util Date  amp  Calendar classes bundled with Java  They are notoriously troublesome  Use either the Joda-Time library or Java 8   s new java time package  inspired by Joda-Time  defined by JSR 310    java time  The java time classes use standard ISO 8601 formats by default when parsing and generating strings   OffsetDateTime odt   OffsetDateTime parse   2014-02-27T23 03 14 05 30      Instant instant   Instant parse   2014-02-27T23 03 14Z       Parse your count of milliseconds since the epoch of first moment of 1970 in UTC   Instant instant   Instant ofEpochMilli   1 393 572 325 000L         instant toString    2014-02-28T07 25 25Z   Adjust that Instant into a desired time zone   ZoneId z   ZoneId of   America Montreal     ZonedDateTime zdt   instant atZone  z         zdt toString    2014-02-28T02 25 25-05 00 America Montreal      About java time  The java time framework is built into Java 8 and later  These classes supplant the troublesome old legacy date-time classes such as java util Date  Calendar   amp  SimpleDateFormat   The Joda-Time project  now in maintenance mode  advises migration to the java time classes   To learn more  see the Oracle Tutorial  And search Stack Overflow for many examples and explanations  Specification is JSR 310   You may exchange java time objects directly with your database  Use a JDBC driver compliant with JDBC 4 2 or later  No need for strings  no need for java sql   classes   Where to obtain the java time classes     Java SE 8  Java SE 9  Java SE 10  and later   Built-in   Part of the standard Java API with a bundled implementation  Java 9 adds some minor features and fixes   Java SE 6 and Java SE 7   Much of the java time functionality is back-ported to Java 6  amp  7 in ThreeTen-Backport   Android   Later versions of Android bundle implementations of the java time classes  For earlier Android   lt 26   the ThreeTenABP project adapts ThreeTen-Backport  mentioned above   See How to use ThreeTenABP        The ThreeTen-Extra project extends java time with additional classes  This project is a proving ground for possible future additions to java time  You may find some useful classes here such as Interval  YearWeek  YearQuarter  and more     Joda-Time  UPDATE  The Joda-Time project  now in maintenance mode  advises migration to the java time classes   Joda-Time uses ISO 8601 as its defaults    A Joda-Time DateTime object knows its on assigned time zone  unlike a java util Date object   Generally better to specify a time zone explicitly rather than rely on default time zone   Example Code  long input   1393572325000L  DateTime dateTimeUtc   new DateTime  input  DateTimeZone UTC     DateTimeZone timeZoneIndia   DateTimeZone forID   Asia Kolkata     DateTimeZone timeZoneIreland   DateTimeZone forID   Europe Dublin      DateTime dateTimeIndia   dateTimeUtc withZone  timeZoneIndia    DateTime dateTimeIreland   dateTimeIndia withZone  timeZoneIreland        Use a formatter to create a String representation  The formatter can adjust time zone if you so desire  DateTimeFormatter formatter   DateTimeFormat forStyle   FM    withLocale  Locale CANADA FRENCH   withZone  DateTimeZone forID   America Montreal       String output   formatter print  dateTimeIreland      Dump to console        All three of these date-time objects represent the  same  moment in the timeline of the Universe  System out println   dateTimeUtc      dateTimeUtc    System out println   dateTimeIndia      dateTimeIndia    System out println   dateTimeIreland      dateTimeIreland     System out println   output for Montr  al      output      When run     dateTimeUtc  2014-02-28T07 25 25 000Z dateTimeIndia  2014-02-28T12 55 25 000 05 30 dateTimeIreland  2014-02-28T07 25 25 000Z output for Montr  al  vendredi 28 f  vrier 2014 02 25 25         Actually  java util Date does have a time zone  That time zone is assigned deep in its source code  Yet the class ignores that time zone for most practical purposes  And its toString method applies the JVM   s current default time zone rather than that internal time zone  Confusing  Yes  This is one of many reasons to avoid the old java util Date  Calendar classes  Use java time and or Joda-Time instead

[java] Get Date Object In UTC format in Java

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