Regarding leap second change on 31st Dec 2016 at 23:59:60

[Amit Mishra]

Hello Charlie/Poonam/JDK team,

As we all know that leap second is going to happen on 31st Dec 2016 23:59:59 whereas an extra second(23:59:60) will be added to UTC time zone(& to local offset for rest of world) and for that Oracle has released tzdata2016g tzupdate which needs to be installed for all JRE instances.

My question is if system(OS clock) will be synced by NTP server for this change even then if there will be need for this tzdata patch to be installed or not for applications running on Java 1.6 ?
What are associated risks if we don't update JRE instances time zone data using tzdata2016g ?

Also I want to understand how Java different data/time API on 1.6 calculate current time , does it takes from system clock or it has any other mechanism or reference source from where it can derives accurate current time ?

In case if it is taking from system clock then why Oracle is releasing tzupdates as current time will synced to all Java application just after restart as they will fetch correct time from system clock(which is updated via ntp).

I am bit confused about how IANA database updates are helping Java apps for time related calculation in case if Java solely depends upon system clock for reference clock source.

Your prompt response will be appreciated.

Many thanks for support and cooperation.

Regards,
Amit Mishra
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.openjdk.java.net/pipermail/hotspot-gc-use/attachments/20161223/5d322a62/attachment.html>