Link to home
Start Free TrialLog in
Avatar of paries
paries

asked on

having trouble with time zones and daylight savings

So i have this time in my DB
1300550400000
from what i read the display should no if to display daylight or not

when i run this code::
SmsEvents.getStart() returns 1300550400000


        TimeZone pTz = TimeZone.getTimeZone( "PST" );
        DateFormat pdf = DateFormat.getDateTimeInstance( DateFormat.LONG,DateFormat.LONG );
        pdf.setTimeZone( pTz );
        Calendar dayp = Calendar.getInstance();
        dayp.setTimeZone( pTz );
        dayp.setTime( new Date((long)SmsEvents.getStart())  );
        System.out.println( pdf.format( dayp.getTime() ) );

        TimeZone mTz = TimeZone.getTimeZone( "MST" );
        DateFormat mdf = DateFormat.getDateTimeInstance( DateFormat.LONG,DateFormat.LONG );
        mdf.setTimeZone( mTz );
        Calendar daym = Calendar.getInstance();
        daym.setTimeZone( mTz );
        daym.setTime( new Date((long)SmsEvents.getStart())  );
        System.out.println( mdf.format( daym.getTime() ) );

        TimeZone cTz = TimeZone.getTimeZone( "CST" );
        DateFormat cdf = DateFormat.getDateTimeInstance( DateFormat.LONG,DateFormat.LONG );
        cdf.setTimeZone( cTz );
        Calendar dayc = Calendar.getInstance();
        dayc.setTimeZone( cTz );
        dayc.setTime( new Date((long)SmsEvents.getStart())  );
        System.out.println( cdf.format( dayc.getTime() ) );


i get the following results::
March 19, 2011 9:30:00 AM PDT
March 19, 2011 9:30:00 AM MST
March 19, 2011 11:30:00 AM CDT

why is mountain doing this. Am i doing something wrong?
I am confused







Avatar of for_yan
for_yan
Flag of United States of America image
What is it that you don't like?
seems logical to me, I guess MST will give the same number as PDT
CDT is two hours difference with PDT
and I guess MDT will be one hour difference with PDT.
Isn't that what you'll expect?
Avatar of paries
paries

ASKER

so my question is why is it
March 19, 2011 9:30:00 AM MST

should it have not been MDT??

Avatar of for_yan
for_yan
Flag of United States of America image


I got different output:


March 19, 2011 8:00:00 AM PST
March 19, 2011 9:00:00 AM MST
March 19, 2011 10:00:00 AM CST

Open in new window


I just modified your code a little bit (replacing SMSEvent):

     TimeZone pTz = TimeZone.getTimeZone( "PST" );
            DateFormat pdf = DateFormat.getDateTimeInstance( DateFormat.LONG, DateFormat.LONG );
            pdf.setTimeZone( pTz );
            Calendar dayp = Calendar.getInstance();
            dayp.setTimeZone( pTz );
            dayp.setTime( new Date((long)1300550400000L));
            System.out.println( pdf.format( dayp.getTime() ) );

            TimeZone mTz = TimeZone.getTimeZone( "MST" );
            DateFormat mdf = DateFormat.getDateTimeInstance( DateFormat.LONG,DateFormat.LONG );
            mdf.setTimeZone( mTz );
            Calendar daym = Calendar.getInstance();
            daym.setTimeZone( mTz );
            daym.setTime( new Date((long)1300550400000L)  );
            System.out.println( mdf.format( daym.getTime() ) );

            TimeZone cTz = TimeZone.getTimeZone( "CST" );
            DateFormat cdf = DateFormat.getDateTimeInstance( DateFormat.LONG,DateFormat.LONG );
            cdf.setTimeZone( cTz );
            Calendar dayc = Calendar.getInstance();
            dayc.setTimeZone( cTz );
            dayc.setTime( new Date((long)1300550400000L)  );
            System.out.println( cdf.format( dayc.getTime() ) );

Open in new window


Avatar of for_yan
for_yan
Flag of United States of America image
When I changed all thre of them to
PDT, MDT nd CDT I got everything in GMT, like that:


March 19, 2011 4:00:00 PM GMT
March 19, 2011 4:00:00 PM GMT
March 19, 2011 4:00:00 PM GMT

Open in new window


Interesting, indeed
Avatar of paries
paries

ASKER

i am running 1.5 i bet you you are running 1.6
Avatar of for_yan
for_yan
Flag of United States of America image
I was just posting that I  have Java 1.5 (1.5.0_01)
(even more surprising).
Did you change to that same long number (just to have the codes identical).
Avatar of for_yan
for_yan
Flag of United States of America image
I'm in Pacific zone, so my local time is 11:06 I guess it is PDT
Avatar of paries
paries

ASKER

so i am using jdk1.5.0_15
wow this is so confusing....

I am at a loss
thats for you help.
Avatar of for_yan
for_yan
Flag of United States of America image
It looks like my java does not understand PDT, CDT, MDT;
when I put "ABC" instaed - I also get GMT time in the result
Avatar of paries
paries

ASKER

yeah that is the same with me.
but if i put in CST it realized i am in daylight savings and shows CDT
Avatar of paries
paries

ASKER

wow, so i took this very simple jsp and moved to a 1.6.0_20 box

go the same results
March 19, 2011 11:25:22 AM PDT
March 19, 2011 11:25:22 AM MST
March 19, 2011 1:25:22 PM CDT



<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">

<%@ page import="java.text.SimpleDateFormat" %>
<%@ page import="java.util.*" %>
<%@ page import="java.text.DecimalFormat" %>
<%@ page import="java.text.DateFormat" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>

<%
        Date now2 = new Date();

        TimeZone pTz = TimeZone.getTimeZone( "PST" );
        DateFormat pdf = DateFormat.getDateTimeInstance( DateFormat.LONG,DateFormat.LONG );
        pdf.setTimeZone( pTz );
        Calendar dayp = Calendar.getInstance();
        dayp.setTimeZone( pTz );
        dayp.setTime( now2  ) ;
        System.out.println( pdf.format( dayp.getTime() ) );

        TimeZone mTz = TimeZone.getTimeZone( "MST" );
        DateFormat mdf = DateFormat.getDateTimeInstance( DateFormat.LONG,DateFormat.LONG );
        mdf.setTimeZone( mTz );
        Calendar daym = Calendar.getInstance();
        daym.setTimeZone( mTz );
        daym.setTime( now2 );
        System.out.println( mdf.format( daym.getTime() ) );

        TimeZone cTz = TimeZone.getTimeZone( "CST" );
        DateFormat cdf = DateFormat.getDateTimeInstance( DateFormat.LONG,DateFormat.LONG );
        cdf.setTimeZone( cTz );
        Calendar dayc = Calendar.getInstance();
        dayc.setTimeZone( cTz );
        dayc.setTime( now2 );
        System.out.println( cdf.format( dayc.getTime() ) );

%>
Avatar of for_yan
for_yan
Flag of United States of America image
I'll be in the office this afternoon; I have sveral java's there including 1.6 - I'll give it a try
Avatar of for_yan
for_yan
Flag of United States of America image
All that looks really strange
Avatar of paries
paries

ASKER

after some googling seems to be a common problem
if i do TimeZone mTz = TimeZone.getTimeZone( "America/Denver" );
it displays correctly
I think i am going to go that route
thanks for all your help

Avatar of for_yan
for_yan
Flag of United States of America image
And thanks for this interesting news also
ASKER CERTIFIED SOLUTION
Avatar of CEHJ
CEHJ
Flag of United Kingdom of Great Britain and Northern Ireland image
Link to home
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
Start Free Trial
Avatar of for_yan
for_yan
Flag of United States of America image
If all stuff which is deprecated in Java would stop working today - we'll have a disaster much worse than any Japanese tsunami.
Avatar of CEHJ
CEHJ
Flag of United Kingdom of Great Britain and Northern Ireland image
Well tzs are a little different than stuff like deprecated methods:

a. they are a moving target for Java
b. they're already either buggy or borderline buggy

For those reasons, it's worth running the tzupdater tool - it won't do you any harm and might do some good