Predictable problems with 3-character time zones, especially the EST/EST5EDT split.

[Masayoshi Okutsu]

In JDK 1.1, 3-letter time zone IDs, which I think came from the Taligent 
OS, were used. "EST" is U.S. Eastern Time. Yes. It's confusing. Probably 
S stands for Standard and Summer. :-)

When I took over the date/time API responsibility from IBM 
(ex-Taligent), I decided to change the whole time zone support mechanism 
in Java. The result went to J2SE 1.4. At that time I got a request that 
Java support the full set of the tz database IDs. Then, I gave the 
priority to the tz database IDs. "MET" (Middle East Time in JDK 1.1) was 
changed at that time. When "EST", "MST", and "HST" were added in 
tzdata2005r, if I remember correctly, I didn't change the "policy"...

I had to agree to support the "compatibility mode flag" to deal with the 
conflicting requirements, tz database compatibility and JDK 1.1 
compatibility. But I haven't implemented it yet...

Thanks,
Masayoshi

Paul Eggert wrote:
> John Stainforth <STAIN at uk.ibm.com> writes:
>   
>> http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6466476 which contains
>> the assertion: "This means that all legacy Applets and applications which
>> used EST before are now broken".
>>     
>
> This is all news to me.  But it appears to be an issue with Java's old
> names for time zones, not with the Olson database per se.  So you'll
> have to resolve it at the Java level.
>
> You might just want to do what Sun is doing in JDK 7, and add a
> compatibility mode flag.  Set the flag one way, and you get the
> traditional Java behavior where "EST" means eastern time with daylight
> saving (did it really mean that? wow, that's confusing).  Set the flag
> the other way, and "EST" means eastern time without daylight saving
> (which is the traditional real-world meaning in this country, and is
> the traditional Olson interpretation as well).  Perhaps you can ask
> Sun exactly how that flag will work, and how it will affect "HST",
> "MST", "PST", etc.
>
> I'll CC: this message to the tz list to see whether others have
> noticed the problem.
>