RE: Time zones are driving me CRAZY [still more BUGS]
RE: Time zones are driving me CRAZY [still more BUGS]
- Subject: RE: Time zones are driving me CRAZY [still more BUGS]
- From: "Pierre Bernard" <email@hidden>
- Date: Wed, 19 Nov 2003 09:12:39 +0100
- Thread-topic: JavaClient performance vs. JDK 1.4.1
Hi all!
Unfortunately, the workaround detailed in my previous mail only fixes the performance hit inflicted upon applications running on WO 5.2.2. It does not fix other problems I recently mentionned here.
So far, I have determined 3 bugs with timestamps in WO 5.2.2. For two of which I have workarounds. I am in the process of contacting Apple DTS over the third one.
For reference:
1. Using an instance of NSTimeZone with TimeZone.setDefault() causes havoc in date parsing. Workaround: use an instance provided by java.util.TimeZone
2. _NSGregorianCalendar which references a time zone by the name of "UTC". Causes performance hit. See quoted message below.
3. Parsing using NSTimestampFormatter produces results different from parsing using SimpleDateFormat. Only certain windows of time are affected. One such window being the years shortly before 1917. Workaround: none know
It's like WO 5.0 all over again!
Pierre.
--
Got a hang for movies?
http://homepage.mac.com/I_love_my/movies.html
-----Original Message-----
From: Pierre Bernard
Sent: Friday, November 14, 2003 3:15 PM
To: Pierre Bernard; email@hidden
Cc: email@hidden
Subject: RE: Time zones are driving me CRAZY [partially SOLVED]
Hi!
The culprid for the performance problems is indeed a private class named _NSGregorianCalendar which references a time zone by the name of UTC. Unfortunately, the correct way to refer to this time zone is by the name of "etc/UTC".
This name is passed to a method on the TimeZone class to retrieve the actual time zone information. When called, this method lazily retieves the time zone information from a set of files. Sun, in their remarkably infinite wisdom, chose not to have this throw when the appropriate file is not found so you'll never know you got the name wrong. Instead it returns a dummy GMT timezone. Upon the next call the file system is again checked for the missing file. These countless IO operations cause a major performance hit.
I have yet to determine if this bug is also responsible for the erratic behavior I am seeing with timestamps. It most likely is - due to the fact that UTC and GMT are not equal, yet where Apple expects to get UTC, Sun merrily hands over GMT.
Thus, if you see performance problems with timestamp related operations - or just want to considerably speed up your application - you know what to do. :-)
I'll file a bug report shortly. Expecting at least a medal for this. :-)
Pierre
--
Got a hang for movies?
http://homepage.mac.com/I_love_my/movies.html
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