Java and U.S. Daylight Saving Time (DST) Alert

Time Zone Updater Tool for 1.4.x/5.0.x

HP Alert Notification (March 9, 2007)

Introduction

• Sun Alert ID: 102836 (http://java.sun.com/developer/technicalArticles/Intl/alert.html)
• Synopsis: Olson TZ data tzdata2005r or greater incompatibility
• Product: Java 2 Platform, Standard Edition
• Corresponding Sun BugIDs: 6466476, 6530336

ACTION REQUIRED: For customers using the affected releases (noted below), or executing tzupdater without the -bc option, HP recommends to reapply tzupdater tool with the command line options: -f -bc.

For the latest tzupdater tool, see http://h18012.www1.hp.com/java/alpha/DST-US.html.

Impact

The introduction of Olson TZ data, version 2005r or greater, may break backward compatibility for the Eastern, Hawaiian, and Mountain time zones, under certain circumstance.

The full problem statement may be found in Sun's bugs 6466476 and 6530336:

http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6466476
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6530336

The Hawaiian TZ is only affected for historical data. Other American TZs such as PST and CST are not affected.

Releases earlier than Java SE v1.4.x are not affected.

Contributing Factors

This condition affects Olson time zone data 2005r or greater, which can be found in:

• OpenVMS Itanium: JDK 5.0-2
• OpenVMS Alpha: JDK 5.0-3 and SDK v 1.4.2-6
• Tru64™ UNIX®: SDK v 1.4.2-6

The condition will also exist if you have run the tzupdater for 1.4.x, or later version, but without the -bc flag.

The condition will be apparent under one of the following two circumstances:

The use of old 3-letter TZ IDs, limited to:
"EST", "HST", "MST".

The parsing of date strings containing one of the following three TZ strings:
"EDT", "HDT", or "MDT".

Symptoms

The result of this condition will be that DST will be calculated incorrectly.

Relief/Workaround

Run tzupdater for v1.4.x, or later, with the command line options:
-f -bc

See the READ ME file for your platform:
http://h18012.www1.hp.com/java/alpha/DST-US.html#downloads

Resolution

To effect the correction (ie. to enable support for the backward compatible DST timezones) use:

1. Run tzupdater for v1.4.x, or later, with the command line options:
   -f -bc
   
   

   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.
   
   NOTE: 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.

2. Install Issues:
   
   In the unlikely event of unforeseen issues (e.g: such as power loss or IO Error) restore the JRE Time Zone files to their original state by:
   

   a) following the instructions in the READ ME file for your platform:

   http://h18012.www1.hp.com/java/alpha/DST-US.html#downloads
   section : "Removing TZupdater Tool Changes"

   OR:

   b) removing and then reinstalling the JRE or JDK.

   The update may now be re-applied by following step 1 above.

3. Application MUST be restarted for changes to take effect.

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