Force Java timezone as GMT UTC

Question

I need to force any time related operations to GMT UTC  regardless the timezone set on the machine  Any convenient way to so in code   To clarify  I m using the DB server time for all operations  but it comes out formatted according to local timezone   Thanks

User · Answer

Hope below code will help you      DateFormat formatDate   new SimpleDateFormat ISO DATE TIME PATTERN       formatDate setTimeZone TimeZone getTimeZone  quot UTC quot          formatDate parse dateString

User · Answer

You could change the timezone using TimeZone setDefault     TimeZone setDefault TimeZone getTimeZone  GMT

User · Answer

I had to set the JVM timezone for Windows 2003 Server because it always returned GMT for new Date     -Duser timezone America Los Angeles  Or your appropriate time zone  Finding a list of time zones proved to be a bit challenging also     Here are two list   http   wrapper tanukisoftware com doc english prop-timezone html  http   publib boulder ibm com infocenter iseries v5r3 index jsp topic  2Frzatz 2F51 2Fadmin 2Freftz htm

User · Answer

for me  just quick SimpleDateFormat      private static final SimpleDateFormat GMT   new SimpleDateFormat  yyyy-MM-dd      private static final SimpleDateFormat SYD   new SimpleDateFormat  yyyy-MM-dd      static         GMT setTimeZone TimeZone getTimeZone  GMT         SYD setTimeZone TimeZone getTimeZone  Australia Sydney           then format the date with different timezone

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tl dr  String sql    SELECT CURRENT TIMESTAMP       OffsetDateTime odt   myResultSet getObject  1   OffsetDateTime class       Avoid depending on host OS or JVM for default time zone  I recommend you write all your code to explicitly state the desired expected time zone  You need not depend on the JVM   s current default time zone  And be aware that the JVM   s current default time zone can change at any moment during runtime  with any code in any thread of any app calling TimeZone setDefault  Such a call affects all apps within that JVM immediately   java time  Some of the other Answers were correct  but are now outmoded  The terrible date-time classes bundled with the earliest versions of Java were flawed  written by people who did not understand the complexities and subtleties of date-time handling   The legacy date-time classes have been supplanted by the java time classes defined in JSR 310    To represent a time zone  use ZoneId  To represent an offset-from-UTC  use ZoneOffset  An offset is merely a number of hour-minutes-seconds ahead or behind the prime meridian  A time zone is much more  A time zone is a history of the past  present  and future changes to the offset used by the people of a particular region      I need to force any time related operations to GMT UTC   For an offset of zero hours-minutes-seconds  use  the constant ZoneOffset UTC    Instant  To capture the current moment in UTC  use an Instant  This class represent a moment in UTC  always in UTC by definition   Instant instant   Instant now         Capture current moment in UTC    ZonedDateTime  To see that same moment through the wall-clock time used by the people of a particular region  adjust into a time zone  Same moment  same point on the timeline   different wall-clock time   ZoneId z   ZoneId of   Asia Tokyo      ZonedDateTime zdt   instant atZone  z       Database  You mention a database   To retrieve a moment from the database  your column should be of a data type akin to the SQL-standard TIMESTAMP WITH TIME ZONE  Retrieve an object rather than a string  In JDBC 4 2 and later  we can exchange java time objects with the database  The OffsetDateTime is required by JDBC  while Instant  amp  ZonedDateTime are optional    OffsetDateTime odt   myResultSet getObject        OffsetDateTime class       In most databases and drivers  I would guess  that you will get the moment as seen in UTC  But if not  you can adjust in either of two ways    Extract a Instant   odt toInstant   Adjust from the given offset to an offset of zero  OffsetDateTime odtUtc   odt withOffsetSameInstant  ZoneOffset UTC               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   To learn more  see the Oracle Tutorial  And search Stack Overflow for many examples and explanations  Specification is JSR 310   The Joda-Time project  now in maintenance mode  advises migration to the java time classes   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  Java SE 11  and later  - 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   Most 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

User · Answer

Also if you can set JVM timezone this way  System setProperty  user timezone    EST      or -Duser timezone GMT in the JVM args

User · Answer

Wow  I know this is an ancient thread but all I can say is do not call TimeZone setDefault   in any user-level code  This always sets the Timezone for the whole JVM and is nearly always a very bad idea  Learn to use the joda time library or the new DateTime class in Java 8 which is very similar to the joda time library

User · Answer

Use system property   -Duser timezone UTC

User · Answer

Execute this line in MySQL to reset your timezone  SET   global time zone     00 00

User · Answer

If you would like to get GMT time only with intiger      var currentTime   new Date        var currentYear   2010      var currentMonth   10      var currentDay   30      var currentHours   20      var currentMinutes   20      var currentSeconds   00      var currentMilliseconds   00   currentTime setFullYear currentYear   currentTime setMonth  currentMonth-1      0is January currentTime setDate currentDay     currentTime setHours currentHours   currentTime setMinutes currentMinutes   currentTime setSeconds currentSeconds   currentTime setMilliseconds currentMilliseconds    var currentTimezone   currentTime getTimezoneOffset    currentTimezone    currentTimezone 60    -1  var gmt      if  currentTimezone     0      gmt    currentTimezone  gt  0                 gmt    currentTimezone    alert gmt

User · Answer

The OP answered this question to change the default timezone for a single instance of a running JVM  set the user timezone system property   java -Duser timezone GMT      lt main-class gt    If you need to set specific time zones when retrieving Date Time Timestamp objects from a database ResultSet  use the second form of the getXXX methods that takes a Calendar object   Calendar tzCal   Calendar getInstance TimeZone getTimeZone  GMT     ResultSet rs        while  rs next          Date dateValue   rs getDate  DateColumn   tzCal          Other fields and calculations     Or  setting the date in a PreparedStatement   Calendar tzCal   Calendar getInstance TimeZone getTimeZone  GMT     PreparedStatement ps   conn createPreparedStatement  update        ps setDate  DateColumn   dateValue  tzCal      Other assignments ps executeUpdate      These will ensure that the value stored in the database is consistent when the database column does not keep timezone information   The java util Date and java sql Date classes store the actual time  milliseconds  in UTC  To format these on output to another timezone  use SimpleDateFormat  You can also associate a timezone with the value using a Calendar object   TimeZone tz   TimeZone getTimeZone   lt local-time-zone gt           Date dateValue   rs getDate  DateColumn    Calendar calValue   Calendar getInstance tz   calValue setTime dateValue     Usefull Reference  https   docs oracle com javase 9 troubleshoot time-zone-settings-jre htm JSTGD377  https   confluence atlassian com kb setting-the-timezone-for-the-java-environment-841187402 html

User · Answer

I would retrieve the time from the DB in a raw form  long timestamp or java s Date   and then use SimpleDateFormat to format it  or Calendar to manipulate it  In both cases you should set the timezone of the objects before using it   See SimpleDateFormat setTimeZone     and Calendar setTimeZone     for details

User · Answer

create a pair of client   server  so that after the execution  client server sends the correct time and date  Then  the client asks the server pm GMT and the server sends back the answer right

[java] Force Java timezone as GMT/UTC

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