Java Time Ignores Daylight Saving Rules

- 1 answer

I am exporting TZ variable in POSIX format to set timezone on Linux. For instance:

export TZ="EST+5EDT,M3.2.0/02:00,M11.1.0/02:00"

Linux date command returns:

Wed Mar 14 03:47 EDT 2018

Java returns:


It seems that Java does not take into account DST rule. What can be wrong?



I'm not sure what linux version you're using, but I've tested in Red Hat 4.4 and it accepts IANA's names:

export TZ=America/New_York

And the output is:

Qua Mar 14 08:37:25 EDT 2018

I've also checked some articles on web and all examples use names like "America/New_York", "Europe/London" and so on.

But anyway, if your linux version doesn't work with this, it's better to change your code to not use the JVM default timezone:"America/New_York"));

Actually, I think it's better to use a specific timezone, because the default can be changed at runtime, for any application running in the same JVM. Even if you have control over what the applications do, some infrastructure/environment maintainance can change that, either on purpose or by accident - it happened to me once, which made me start using explicit timezones names everywhere.

And always prefer IANA's names, in the format Continent/Region. Names like EST+5EDT are fixed, in the sense that they represent just an offset (in this case, GMT-05:00), without any Daylight Saving rules. Only names like America/New_York contains DST rules.