Time Zone issues EDT to PDT conversion. Really need help!

Question

Have a question regarding conversion from EDT to PDT time zones and on different Java versions...
If you compile the program below and run it using JRE 1.6, 1.5 versus 1.4, 1.3 it gives different results. Maybe somebody has an answer:
Here is the code:
import java.text.*;
import java.util.*;
public class Moh {
        public static void main(String[] args) throws Exception {
                SimpleDateFormat timestampFormatWithZone = new SimpleDateFormat("yyyy-MM-dd HH:mm z");
                Date date = timestampFormatWithZone.parse("2007-06-06 14:00 EDT");
                System.out.println(date.toString());
}Copile it and run using these two options. The one with
New York shall show you 2pm or 14:00 and when using the
second one output changes:
java -Duser.timezone=America/New_York Moh
java -Duser.timezone=America/Los_Angeles Moh
If you use JRE 1.6 or 1.5 second option will give you 12:00; if you
use JRE 1.4 or JRE 1.3 it will show 11am or 11:00
I think that 11am is correct! Is there any issues with newer JREs and timezone conversion. Or am I missing anything?
Thank you so much for your help!

Answer 1

Yes, there are issues. See the following from Sun Microsystems
Sun(sm) Alert Notification
    * Sun Alert ID: 102836
    * Synopsis: Olson TZ Data (tzdata2005r or
greater) Incompatibility Issues
    * Category: Availability
    * Product: Java 2 Platform, Standard Edition
    * BugIDs: 6466476, 6530336
    * Avoidance: Upgrade
    * State: Resolved
    * Date Released: 08-Mar-2007
    * Date Closed: 08-Mar-2007
    * Date Modified:
1. Impact
The introduction of Olson Timezone (TZ) data,
version 2005r or greater, may break backward
compatibility for the Eastern, Hawaiian, and
Mountain time zones, under certain circumstances.
This issue is also outlined in Sun BugIDs 6466476
and 6530336, listed at:
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6466476
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6530336
Note: The Hawaiian TZ is only affected for
historical data. Other American TZs such as PST and
CST are not affected.
2. Contributing Factors
This issue can occur in the following releases for
all platforms:
    * JDK and JRE v1.4.2_12 and above
    * JDK and JRE 5.0u8 and above
    * JDK and JRE 6 and above
Notes:
   1. Releases below Java SE v1.4.x are not affected
by this issue.
   2. The condition will also exist if you have run
the "Time Zone Updater Tool" for v1.4.x+, but
without the -bc flag.
This condition will be apparent under one of the
following two circumstances:
A) The use of old 3-letter TZ IDs, limited to:
"EST", "HST", "MST".
Or:
B) The parsing of date strings containing one of the
following three TZ strings: "EDT", "HDT", or "MDT".
3. Symptoms
The symptoms/result of this condition will be that
Daylight Saving Time (DST) will be calculated
incorrectly.
4. Relief/Workaround
There is no workaround for this issue. Please see
the Resolution section below.
5. Resolution
To resolve this issue (ie. to enable support for the
backward compatible DST timezones), run the "Time
Zone Updater Tool" for v1.4.x+ with the command line
options:
    -f -bc
Complete instructions for running the tool can be
found at:
http://java.sun.com/javase/tzupdater_README.html
Note: If you have already run without the -bc flag,
you will need to rerun with the -f -bc flag to
correctly resolve the 3-letter TZ abbreviation issue.
The -bc options will result in the deletion of the
files:
    * JAVAHOME/jre/lib/zi/EST
    * JAVAHOME/jre/lib/zi/MST
    * JAVAHOME/jre/lib/zi/HST
There are no known side effects to removing these files.
Install Issues :
In the unlikely event of unforeseen issues (e.g:
such as power loss or I/O Error) restore the JRE
Time Zone files to their original state by:
A) following the instructions at
http://java.sun.com/javase/tzupdater_README.html#remove
Or:
B) removing and then reinstalling the JRE or JDK.
The update may now be re-applied by running the TZ
Updater Tool (with the proper command line options)
as listed above.
For additional information on issues, products, and
resources for DST changes, please also see:
http://www.sun.com/dst
This Sun Alert notification is being provided to you
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