Configure DST(Daylight Savings Time) in log4j

Question

I need to configure DST time for some application running in a server which is in Fiji. OS level time has configured properly :

Tue Nov 11 17:28:51 **FJST** 2014

(FJST - Fiji Summer Time)

I have changed the log4j.xml configuration as follow and tried:

<layout class="org.apache.log4j.EnhancedPatternLayout">
  <param name="ConversionPattern" value="%d{ISO8601}{GMT+13} %-5p %c{1} [%x] [%t] - %m%n" />

This works bit fine, but this can be a workaround only, can't be a solution. Following two issues are there:

1. Need to restart all the application two times. During every DST changes service interruption will be there. It's not possible for production.

2. We can't say, every day the time change will be exactly +/- 1 hour. Some days it can be like 50 mins. So in that case, log won't be updated with proper time.

Is there any patch available for following java version to fix this ? - "1.7.0_09-icedtea"

Else is there any way to change the log4j time as OS time? If so that will be a great solution since there won't be much service interruption.

Answer 1

According to the docs for EnhancedPatternLayout, the value in the second set of braces following %d is a string to be passed internally to TimeZone.getTimeZone(String), which states the string should be:

The ID for a TimeZone, either an abbreviation such as "PST", a full name such as "America/Los_Angeles", or a custom ID such as "GMT-8:00".

Therefore, you should be able to pass Pacific/Fiji, to automatically use the correct time zone offset at different times of the year.

<param name="ConversionPattern" value="%d{ISO8601}{Pacific/Fiji} %-5p %c{1} [%x] [%t] - %m%n" />

Also, historically Fiji has been known for not providing adequate notice when setting their DST dates. Most countries try to establish a stable recurrence pattern, but Fiji has chosen to announce DST changes each individual year. The latest change for 2014 was announced on Oct 20th, and went into effect on Nov 2nd - leaving only 12 days to implement and distribute changes to the time zone databases. The IANA tzdb group acted quickly, releasing version 2014i on Oct 22, and Oracle then issued the corresponding TZUpdater 1.4.9 on Oct 31 to incorporate this change.

Make sure you download TZUpdater 1.4.9 or greater and apply it to your environment. As long as Fiji is unstable, you will likely need to do this in the future as well. That means your fist bullet point about not wanting to restart production is an impossibility. One cannot predict the government.

Regarding your second bullet point: There are no time zones anywhere in the world that shift by 50 minutes. All that use DST shift by one whole hour, except for Australia/Lord_Howe which shifts by 30 minutes.