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  1. JDK
  2. JDK-6390869

TimeZone.getDefault() returns different timezones for Windows GMT-12 when DST is checked and not.

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    • b76
    • x86
    • windows_2000, windows_xp

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      Description

        Hardware: Pentium IV
        OS: Windows XP Professional SP2
        Java version: java version "1.5.0_06"
        Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_06-b05)
        Java HotSpot(TM) Client VM (build 1.5.0_06-b05, mixed mode, sharing)

        Problem: TimeZone.getDefault() returns two different timezones for Windows GMT-12 regarding to the 'Automatically adjust clock for daylight saving changes' is checked and not. When the daylight saving adjustment checkbox is off, java correctly recogizes GMT-12 as "GMT-12:00". But when it's checked on, Pacific/Majuro is returned, whose timezone is GMT+12.

        Test case: A simple program is provided to re-produce the problem. It can be re-produced always.
        //////////////////////////////////////////////////////////////
        // TestTimeZone.java - BEGIN //
        //////////////////////////////////////////////////////////////
        import java.util.*;

        public class TestTimeZone
        {
          public static void main(String[] args)
          {
            System.out.println("timezone is " + TimeZone.getDefault());
            System.out.println("time is " + new Date());
          }
        }
        //////////////////////////////////////////////////////////////
        // TestTimeZone.java - END //
        //////////////////////////////////////////////////////////////

        Steps to re-produce:
        1. Compile the above program.
        2. Select Windows XP timezone as (GMT+10:00) Canberra, Melbourne, Sydney.
        3. Un-check the 'Automatically adjust clock for daylight saving changes' checkbox.
        4. Change the timezone to (GMT-12:00) International Dateline West.
        5. Run the test program. It should give you a similar output like below. It's correct.

        =========== step 5 output begin ===============
        timezone is sun.util.calendar.ZoneInfo[id="GMT-12:00",offset=-43200000,dstSavings=0,useDaylight=false,transitions=0,lastRule=null]
        time is Sun Feb 26 18:39:02 GMT-12:00 2006
        =========== step 5 output end ==================

        6. Select Windows XP timezone again as (GMT+10:00) Canberra, Melbourne, Sydney.
        7. Check on the 'Automatically adjust clock for daylight saving changes'.
        8. Change the timezone to (GMT-12:00) International Dateline West.
        9. Run the test program again. It'll give you a similar output like below. It's incorrect.

        =========== step 9 output begin ===============
        timezone is sun.util.calendar.ZoneInfo[id="Pacific/Majuro",offset=43200000,dstSavings=0,useDaylight=false,transitions=4,lastRule=null]
        time is Mon Feb 27 18:37:53 MHT 2006
        =========== step 9 output end ==================

        Notice that, Pacific/Majuro is a timezone of GMT+12. So the application gets 24-hours time difference as the DST is on and not for GMT-12 on Windows.

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                peytoia Yuka Kamiya (Inactive)
                lingyul Ling-Yun Li (Inactive)
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