Timezones and versions of Java

Discussion in 'Java' started by loial, May 23, 2011.

  1. loial

    loial Guest

    I am trying to convert BST times to EST.

    The following code correctly returns a difference of 5 hours between
    the 2 times when run under Java 1.5. :

    Local Offset 3600000
    EST Offset -14400000
    EST time Tue May 04 07:48:18 2010
    BST time Tue May 04 12:48:18 2010


    However if run under Java 1.6 (on the same machine), it returns a time
    difference of 6 hours :

    Local Offset 3600000
    EST Offset -18000000
    EST time Tue May 04 06:48:18 2010
    BST time Tue May 04 12:48:18 2010


    Do I need to do something different in Java 1.6?.

    Platform is linux.






    class testtz {
    public static void main(String[] args) {


    Date date = null;

    SimpleDateFormat dateFormat = new
    SimpleDateFormat("yyyyMMddHHmmss");

    try {

    date = dateFormat.parse("20100504124818");
    }
    catch(ParseException pe) {
    System.out.println("Error");
    }

    TimeZone tz1 = TimeZone.getDefault();

    long localOffset = tz1.getOffset(date.getTime());

    System.out.println("Local Offset " + localOffset);

    TimeZone tz2 = TimeZone.getTimeZone("EST");

    long remoteOffset = tz2.getOffset(date.getTime());

    System.out.println("EST Offset " + remoteOffset);


    Date dateToPutInDB = new Date(date.getTime() - localOffset +
    remoteOffse;


    System.out.println("EST time " + dateToPutInDB)

    System.out.println("BST time " + date);



    }

    }
     
    loial, May 23, 2011
    #1
    1. Advertising

  2. loial

    Nigel Wade Guest

    On 23/05/11 15:38, loial wrote:
    > I am trying to convert BST times to EST.
    >
    > The following code correctly returns a difference of 5 hours between
    > the 2 times when run under Java 1.5. :


    Not it doesn't, it doesn't even compile. Post the actual code you are
    running.

    --
    Nigel Wade
     
    Nigel Wade, May 23, 2011
    #2
    1. Advertising

  3. loial

    loial Guest

    import java.util.*;
    import java.text.*;
    class testtz {
    public static void main(String[] args) {


    Date date = null;


    SimpleDateFormat dateFormat = new
    SimpleDateFormat("yyyyMMddHHmmss");


    try {


    date = dateFormat.parse("20100504124818");
    }
    catch(ParseException pe) {
    System.out.println("Error");
    }


    TimeZone tz1 = TimeZone.getDefault();


    long localOffset = tz1.getOffset(date.getTime());


    System.out.println("Local Offset " + localOffset);


    TimeZone tz2 = TimeZone.getTimeZone("EST");


    long remoteOffset = tz2.getOffset(date.getTime());


    System.out.println("EST Offset " + remoteOffset);


    Date dateToPutInDB = new Date(date.getTime() - localOffset +
    remoteOffset);


    System.out.println("EST time " + dateToPutInDB);


    System.out.println("BST time " + date);


    }

    }







    On May 23, 3:45 pm, Nigel Wade <> wrote:
    > On 23/05/11 15:38, loial wrote:
    >
    > > I am trying to convert BST times to EST.

    >
    > > The following code correctly returns a difference of 5 hours between
    > > the 2 times when run under Java 1.5. :

    >
    > Not it doesn't, it doesn't even compile. Post the actual code you are
    > running.
    >
    > --
    > Nigel Wade
     
    loial, May 23, 2011
    #3
  4. loial

    Nigel Wade Guest

    On 23/05/11 15:38, loial wrote:
    > I am trying to convert BST times to EST.
    >
    > The following code correctly returns a difference of 5 hours between
    > the 2 times when run under Java 1.5. :
    >
    > Local Offset 3600000
    > EST Offset -14400000
    > EST time Tue May 04 07:48:18 2010
    > BST time Tue May 04 12:48:18 2010



    That time difference is wrong.

    >
    >
    > However if run under Java 1.6 (on the same machine), it returns a time
    > difference of 6 hours :
    >


    BST is 1 hour ahead of GMT, EST is 5 hours behind GMT. That's a total of
    6 hours. (Note: EST does not implement DST, that is EDT).

    > Local Offset 3600000
    > EST Offset -18000000
    > EST time Tue May 04 06:48:18 2010
    > BST time Tue May 04 12:48:18 2010
    >
    >



    --
    Nigel Wade
     
    Nigel Wade, May 23, 2011
    #4
  5. loial

    Lew Guest

    loial wrote:
    > I am trying to convert BST times to EST.


    What time zones do you mean here? Bangladesh Standard Time? British Summer
    Time? Eastern Standard Time in the Caribbean?

    Neither "EST" nor "BST" is a standard time-zone name.

    Have you considered reading the documentation?

    > The following code correctly returns a difference of 5 hours between
    > the 2 times when run under Java 1.5. :
    >
    > Local Offset 3600000
    > EST Offset -14400000
    > EST time Tue May 04 07:48:18 2010


    You do realize that Eastern Time is not "EST" on May 4 anywhere other than
    Australia, right? Any other jurisdiction that uses "EST" as an abbreviation
    is on Summer Time on that date. Therefore you must be referring to Australian
    time, but that's the wrong offset for that zone.

    Please clarify.

    In any case, there's nothing correct in what you show here. Why do you say
    this is a correct return?

    > BST time Tue May 04 12:48:18 2010


    Does Bangladesh have Daylight Saving Time?

    > However if run under Java 1.6 (on the same machine), it returns a time
    > difference of 6 hours :
    >
    > Local Offset 3600000
    > EST Offset -18000000
    > EST time Tue May 04 06:48:18 2010
    > BST time Tue May 04 12:48:18 2010
    >
    >
    > Do I need to do something different in Java 1.6?.


    Maybe give it the right time zone?

    You do realize that Eastern Standard Time in the U.S. is -18000000
    milliseconds offset from UTC, right? So if "EST" is "America/New_York" (and,
    of course, not Daylight Saving Time), then this display is correct.

    What makes you think that it is not correct?

    > Platform is linux [sic].
    >
    > class testtz {


    Class names should start with an upper-case letter.

    > public static void main(String[] args) {
    >
    >
    > Date date = null;


    Why do you set the date to 'null'? It's unnecessary and potentially harmful;
    it certainly is harmful in the code you show here.

    > SimpleDateFormat dateFormat = new
    > SimpleDateFormat("yyyyMMddHHmmss");
    >
    > try {
    >
    > date = dateFormat.parse("20100504124818");


    Here you throw away that 'null' value that you shouldn't have initialized.

    > }
    > catch(ParseException pe) {
    > System.out.println("Error");
    > }
    >
    > TimeZone tz1 = TimeZone.getDefault();


    If you're in the Northern Hemisphere in most jurisdictions, you will not get
    "EST" from this on May 4.

    > long localOffset = tz1.getOffset(date.getTime());
    >
    > System.out.println("Local Offset " + localOffset);
    >
    > TimeZone tz2 = TimeZone.getTimeZone("EST");
    >
    > long remoteOffset = tz2.getOffset(date.getTime());
    >
    > System.out.println("EST Offset " + remoteOffset);
    >
    >
    > Date dateToPutInDB = new Date(date.getTime() - localOffset +
    > remoteOffse;
    >
    >
    > System.out.println("EST time " + dateToPutInDB)
    >
    > System.out.println("BST time " + date);
    >
    >
    >
    > }
    >
    > }


    <http://download.oracle.com/javase/6/docs/api/java/util/TimeZone.html>
    "Three-letter time zone IDs

    "For compatibility with JDK 1.1.x, some other three-letter time zone IDs (such
    as "PST", "CTT", "AST") are also supported. However, their use is deprecated
    because the same abbreviation is often used for multiple time zones (for
    example, "CST" could be U.S. "Central Standard Time" and "China Standard
    Time"), and the Java platform can then only recognize one of them."

    Have you considered reading the documentation?

    RTFM.
    RTFM.
    RTFM.

    --
    Lew
    RTFM.
     
    Lew, May 23, 2011
    #5
  6. In message
    <>, loial
    wrote:

    > Platform is linux.


    Linux has a perfectly serviceable set of timezone files available SYSTEMWIDE
    in /usr/share/zoneinfo; why do subsystems like Java insist on carrying
    around their own, potentially out-of-date and inconsistent copies?
     
    Lawrence D'Oliveiro, May 24, 2011
    #6
  7. On 24/05/2011 01:50, Lawrence D'Oliveiro allegedly wrote:
    > In message
    > <>, loial
    > wrote:
    >
    >> Platform is linux.

    >
    > Linux has a perfectly serviceable set of timezone files available SYSTEMWIDE
    > in /usr/share/zoneinfo; why do subsystems like Java insist on carrying
    > around their own, potentially out-of-date and inconsistent copies?


    The JRE carries regularly updated timezone info (which can be updated
    independently of the JRE) for the purpose of running in environments
    that do not sport a perfectly serviceable set of timezone informations.

    --
    DF.
    An escaped convict once said to me:
    "Alcatraz is the place to be"
     
    Daniele Futtorovic, May 24, 2011
    #7
  8. In message <iretd3$lgu$>, Daniele Futtorovic wrote:

    > On 24/05/2011 01:50, Lawrence D'Oliveiro allegedly wrote:
    >
    >> Linux has a perfectly serviceable set of timezone files available
    >> SYSTEMWIDE in /usr/share/zoneinfo; why do subsystems like Java insist on
    >> carrying around their own, potentially out-of-date and inconsistent
    >> copies?

    >
    > The JRE carries regularly updated timezone info (which can be updated
    > independently of the JRE) for the purpose of running in environments
    > that do not sport a perfectly serviceable set of timezone informations.


    Which is not the case with Linux. Why can it not use zoneinfo when it’s
    available?
     
    Lawrence D'Oliveiro, May 24, 2011
    #8
  9. Lawrence D'Oliveiro wrote:

    > In message <iretd3$lgu$>, Daniele Futtorovic wrote:
    >>
    >> The JRE carries regularly updated timezone info (which can be updated
    >> independently of the JRE) for the purpose of running in environments
    >> that do not sport a perfectly serviceable set of timezone informations.

    >
    > Which is not the case with Linux. Why can it not use zoneinfo when it¢s
    > available?


    Because these files are part of the runtime-classes which are
    Java and are therefor platform independent. BTW: How is Linux
    ensuring that the timezone-files are staying correct? I assume
    by doing the same thing that you do with Java: Update to the
    most current version. Since you do this update for other reasons
    as well (bugfixes, more performance, etc.) I don't see a big
    disadvantage handling timezone-calculations in Java itself.


    Regards, Lothar
    --
    Lothar Kimmeringer E-Mail:
    PGP-encrypted mails preferred (Key-ID: 0x8BC3CD81)

    Always remember: The answer is forty-two, there can only be wrong
    questions!
     
    Lothar Kimmeringer, May 24, 2011
    #9
  10. In message <l0t0ynlpptf2$>, Lothar Kimmeringer wrote:

    > Lawrence D'Oliveiro wrote:
    >
    >> In message <iretd3$lgu$>, Daniele Futtorovic wrote:
    >>>
    >>> The JRE carries regularly updated timezone info (which can be updated
    >>> independently of the JRE) for the purpose of running in environments
    >>> that do not sport a perfectly serviceable set of timezone informations.

    >>
    >> Which is not the case with Linux. Why can it not use zoneinfo when it’s
    >> available?

    >
    > Because these files are part of the runtime-classes which are
    > Java and are therefor platform independent.


    Is that like saying you can never take the plane from an airport in your
    town, because other towns don’t have airports?

    > BTW: How is Linux ensuring that the timezone-files are staying correct?


    Much more easily and quickly than any software vendor can provide software
    patches.

    For example, Chile recently rushed through a bill to extend its daylight-
    saving hours, just days before the period was due to end under the old
    rules. A zoneinfo patch was available that same week
    <http://article.gmane.org/gmane.comp.time.tz/3702>, and has already been
    rolled into the regular release <ftp://elsie.nci.nih.gov/pub/>.

    Has Java been patched for this yet?
     
    Lawrence D'Oliveiro, May 24, 2011
    #10
  11. loial

    Lew Guest

    On 05/24/2011 04:25 AM, Lawrence D'Oliveiro wrote:
    > In message<l0t0ynlpptf2$>, Lothar Kimmeringer wrote:
    >
    >> Lawrence D'Oliveiro wrote:
    >>
    >>> In message<iretd3$lgu$>, Daniele Futtorovic wrote:
    >>>>
    >>>> The JRE carries regularly updated timezone info (which can be updated
    >>>> independently of the JRE) for the purpose of running in environments
    >>>> that do not sport a perfectly serviceable set of timezone informations.
    >>>
    >>> Which is not the case with Linux. Why can it not use zoneinfo when it’s
    >>> available?

    >>
    >> Because these files are part of the runtime-classes which are
    >> Java and are therefor platform independent.

    >
    > Is that like saying you can never take the plane from an airport in your
    > town, because other towns don’t have airports?
    >
    >> BTW: How is Linux ensuring that the timezone-files are staying correct?

    >
    > Much more easily and quickly than any software vendor can provide software
    > patches.
    >
    > For example, Chile recently rushed through a bill to extend its daylight-
    > saving hours, just days before the period was due to end under the old
    > rules. A zoneinfo patch was available that same week
    > <http://article.gmane.org/gmane.comp.time.tz/3702>, and has already been
    > rolled into the regular release<ftp://elsie.nci.nih.gov/pub/>.
    >
    > Has Java been patched for this yet?


    Yes, as you would know if you did even the most minimal checking.

    --
    Lew
    Honi soit qui mal y pense.
    http://upload.wikimedia.org/wikipedia/commons/c/cf/Friz.jpg
     
    Lew, May 24, 2011
    #11
  12. On Tue, 24 May 2011 20:25:01 +1200, Lawrence D'Oliveiro wrote:

    >
    > Is that like saying you can never take the plane from an airport in your
    > town, because other towns don’t have airports?
    >

    No.


    --
    martin@ | Martin Gregorie
    gregorie. | Essex, UK
    org |
     
    Martin Gregorie, May 24, 2011
    #12
  13. Lawrence D'Oliveiro wrote:

    > In message <l0t0ynlpptf2$>, Lothar Kimmeringer wrote:
    >>
    >> Because these files are part of the runtime-classes which are
    >> Java and are therefor platform independent.

    >
    > Is that like saying you can never take the plane from an airport in your
    > town, because other towns don¢t have airports?


    No, it's more like saying, that I prefer wearing my own watch even
    if I reside in an area where you can see public clocks very often.


    Regards, Lothar
    --
    Lothar Kimmeringer E-Mail:
    PGP-encrypted mails preferred (Key-ID: 0x8BC3CD81)

    Always remember: The answer is forty-two, there can only be wrong
    questions!
     
    Lothar Kimmeringer, May 24, 2011
    #13
  14. In message <irg8gm$ibj$>, Martin Gregorie wrote:

    > [rubbish]


    Interesting how not a single one of you has addressed the relevant point.
    Let me repeat it:

    For example, Chile recently rushed through a bill to extend its daylight-
    saving hours, just days before the period was due to end under the old
    rules. A zoneinfo patch was available that same week
    <http://article.gmane.org/gmane.comp.time.tz/3702>, and has already been
    rolled into the regular release <ftp://elsie.nci.nih.gov/pub/>.

    Has Java been patched for this yet?
     
    Lawrence D'Oliveiro, May 25, 2011
    #14
  15. In message <10v5xwjy2wwvr$>, Lothar Kimmeringer wrote:

    > Lawrence D'Oliveiro wrote:
    >
    >> In message <l0t0ynlpptf2$>, Lothar Kimmeringer wrote:
    >>>
    >>> Because these files are part of the runtime-classes which are
    >>> Java and are therefor platform independent.

    >>
    >> Is that like saying you can never take the plane from an airport in your
    >> town, because other towns don’t have airports?

    >
    > No, it's more like saying, that I prefer wearing my own watch even
    > if I reside in an area where you can see public clocks very often.


    No, it’s more like saying you aren’t allowed to use the public clock, you
    must go by my watch.

    Java isn’t giving you the choice of whether to be stupid or clever, it’s
    forcing you to always be stupid.
     
    Lawrence D'Oliveiro, May 25, 2011
    #15
  16. loial

    Lew Guest

    On 05/24/2011 08:04 PM, Lawrence D'Oliveiro wrote:
    > In message<irg8gm$ibj$>, Martin Gregorie wrote:
    >
    >> [rubbish]

    >
    > Interesting how not a single one of you has addressed the relevant point.
    > Let me repeat it:
    >
    > For example, Chile recently rushed through a bill to extend its daylight-
    > saving hours, just days before the period was due to end under the old
    > rules. A zoneinfo patch was available that same week
    > <http://article.gmane.org/gmane.comp.time.tz/3702>, and has already been
    > rolled into the regular release<ftp://elsie.nci.nih.gov/pub/>.
    >
    > Has Java been patched for this yet?


    Again, asked and answered. Yes.

    --
    Lew
    Honi soit qui mal y pense.
    http://upload.wikimedia.org/wikipedia/commons/c/cf/Friz.jpg
     
    Lew, May 25, 2011
    #16
  17. loial

    Roedy Green Guest

    On Mon, 23 May 2011 07:38:54 -0700 (PDT), loial <>
    wrote, quoted or indirectly quoted someone who said :

    >
    >
    >Do I need to do something different in Java 1.6?.


    read the release notes for the two versions and those in between to
    see the corrections made to timezone data. Timezones are as goofy as
    the spellings of female babies. It is big job to keep track of all
    the eccentricities.

    The later version will be the more correct.
    --
    Roedy Green Canadian Mind Products
    http://mindprod.com
    How long did it take after the car was invented before owners understood
    cars would not work unless you regularly changed the oil and the tires?
    We have gone 33 years and still it is rare to uncover a user who
    understands computers don't work without regular backups.
     
    Roedy Green, May 25, 2011
    #17
  18. Wed, 25 May 2011 12:04:30 +1200, /Lawrence D'Oliveiro/:

    > For example, Chile recently rushed through a bill to extend its daylight-
    > saving hours, just days before the period was due to end under the old
    > rules. A zoneinfo patch was available that same week
    > <http://article.gmane.org/gmane.comp.time.tz/3702>, and has already been
    > rolled into the regular release <ftp://elsie.nci.nih.gov/pub/>.
    >
    > Has Java been patched for this yet?


    Java has a TZupdater (Timezone Updater) tool which takes care:

    http://www.oracle.com/technetwork/java/javase/downloads/index-jsp-138363.html#timezone

    http://www.oracle.com/technetwork/java/javase/tzupdater-readme-136440.html

    http://www.oracle.com/technetwork/java/javase/timezones-137583.html

    and yes the exact update you're mentioning seems to be there:

    http://www.oracle.com/technetwork/java/javase/tzdata-versions-138805.html

    That's what Lew has referred to with "you would know if you did even
    the most minimal checking".

    --
    Stanimir
     
    Stanimir Stamenkov, May 25, 2011
    #18
  19. In message <iri87l$no8$>, Stanimir Stamenkov wrote:

    > Wed, 25 May 2011 12:04:30 +1200, /Lawrence D'Oliveiro/:
    >
    >> For example, Chile recently rushed through a bill to extend its daylight-
    >> saving hours, just days before the period was due to end under the old
    >> rules. A zoneinfo patch was available that same week
    >> <http://article.gmane.org/gmane.comp.time.tz/3702>, and has already been
    >> rolled into the regular release <ftp://elsie.nci.nih.gov/pub/>.
    >>
    >> Has Java been patched for this yet?

    >
    > Java has a TZupdater (Timezone Updater) tool which takes care:


    So the answer is “noâ€: you need to download, install and run a separate tool
    to apply a patch to fix it up.

    How many people are going to bother with this?
     
    Lawrence D'Oliveiro, May 25, 2011
    #19
  20. In message <iri87l$no8$>, Stanimir Stamenkov wrote:

    > Java has a TZupdater (Timezone Updater) tool which takes care:


    Actually the link (bypassing the licence-agreement page) is here
    <http://download.oracle.com/otn-pub/java/tzupdater/1.3.38/tzupdater-1_3_38-2011e.zip>.
     
    Lawrence D'Oliveiro, May 25, 2011
    #20
    1. Advertising

Want to reply to this thread or ask your own question?

It takes just 2 minutes to sign up (and it's free!). Just click the sign up button to choose a username and then you can ask your own questions on the forum.
Similar Threads
  1. Ryan Ternier
    Replies:
    1
    Views:
    1,477
    Ryan Ternier
    Oct 14, 2005
  2. Replies:
    2
    Views:
    4,468
  3. MrBlueSky

    timezones and time_t

    MrBlueSky, Aug 18, 2006, in forum: Python
    Replies:
    2
    Views:
    393
    MrBlueSky
    Aug 19, 2006
  4. =?Utf-8?B?U3R1?=

    ASP.NET AJAX Date serialization and timezones

    =?Utf-8?B?U3R1?=, Mar 22, 2007, in forum: ASP .Net
    Replies:
    7
    Views:
    1,259
    =?Utf-8?B?U3R1?=
    Apr 18, 2007
  5. jasonc
    Replies:
    5
    Views:
    1,754
    Arne Vajhøj
    Mar 3, 2009
Loading...

Share This Page