Comment 36 for bug 49068

Revision history for this message
Allen Crider (acrider77) wrote : Re: [Bug 49068] Re: Java reports time zone incorrectly during CDT (US Daylight saving time)

Arik Kfir wrote:
> I'm not familiar with the internals of the JVM, but why does a JVM even
> need its own database? Why can't it use the native OS's timezone
> database, just like it abstracts many other OS services.
>
> Although I'm a Java programmer, I firmly believe that managing the time
> zone information is the system administrator job, since it interacts
> with many other services and processes on the system (cron, backups,
> etc).
>
> Would patching the JVM to make it use Ubuntu's native time-zone database
> be a daunting task, in your opinion? (I'm asking because I'm not at all
> familiar with the actual JVM source code)
>
I haven't looked at much of the JVM source, so I have no idea how
difficult this would be. I would object to doing it just because I
wouldn't expect the Ubuntu team to have to maintain a patch specific to
Ubuntu. I would want any changes made to go into the Sun code where it
would be maintained as part of the upstream version of the JVM. And as
Java is supposed to be cross-platform and provide better security, there
may be a good reason for it not depending on the operating system for
the timezone database.

However, I don't know whether such a change would fix the problem I
reported anyway. The problem I have is that the JVM is sometimes unable
to determine which time-zone it is in. I figured out at one time what
the algorithm was that the JVM uses to determine the correct time-zone,
and it wouldn't work consistently with Ubuntu/Kubuntu, at least not
while DST was in effect. For now, I've gotten around the problem by adding
 export TZ=`cat /etc/timezone`
to /etc/profile. I'm not convinced that that is a good solution, but
there are problems with every other solution that has been suggested.

Allen Crider