The United States has planned a change to its DST observance beginning in 2007. The Energy Policy Act of 2005 mandates that DST will start on the second Sunday in March and end on the first Sunday in November. In 2007, the start and stop dates will be March 11 and November 4, respectively. These dates are different from previous DST start and stop dates. In 2006, the dates were the first Sunday in April (April 2, 2006) and the last Sunday in October (October 29, 2006).

As a Java developer, should you care? Absolutely. This affects the JVM because it compensates for DST in various countries and older JVMs’ information about DST is going to be incorrect. If you haven’t started auditing your systems for DST-readiness you should start. If you are running the most recent JVMs for Java you’ll be covered:

More information on the JVM updates can be found here: http://java.sun.com/developer/technicalArticles/Intl/USDST/

If you have installed WebLogic 8.1 SP6 or newer you’re covered if you’re using the Sun JVM because 1.4.2_11 is included with the update.

Keep in mind that your OS may or may not be ready for the DST change, Microsoft OS users are not.. yet.

For Windows XP Service Pack 2 (SP2), Windows Server 2003, and Windows Server 2003 Service Pack 1 (SP1), Microsoft will release a single global time zone update which will include changes for the United States DST change. This time zone update will also include changes for other related DST changes and time zone behavior and settings that will take place in 2007 or have taken place since these versions of Windows were originally released. It will include some changes that have previously been released as individual hotfixes (such as the Sri Lanka change in time zone offset) or have been individually documented in prior Knowledge Base articles. These updated time zone definitions will also ship with Windows Vista.