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From "Bernt M. Johnsen" <Bernt.John...@Sun.COM>
Subject Re: Date 2042-10-12 problem using Brasilia time zone
Date Tue, 04 Nov 2008 19:09:02 GMT
I have found that this is not related to Brazil tz at all, but to
transtions to DST after 2038-01-19.

When time changes to DST, one hour is skipped. If a Date object is
created within this non-existent hour, java.util.Date adds 1 hour to
the given time to create a legal point in time. After 2038-01-19, due
to some bug in the JDK, 1 hour is subtracted instead. Since
java.sql.Date is an extension on java.util.Date and the fact that
Brazil changes to DST at 00:00:00 and that the time part in
java.util.Date of an java.sql.Date object is set to 00:00:00 1 hour
subtracted from the java.util.Date obect and ends up on 23:00:00 the
day before.

The same bug applies to all locales, but since most locales changes to
DST at 02:00:00 you will not see a date change. If you run the
following program:

package dateproblem;

import java.util.Date;
import java.util.TimeZone;


public class Main {

    static void pDate(int y, int m, int d, int h, int min, int s, String z) {
        TimeZone.setDefault(TimeZone.getTimeZone(z));
        System.out.println(new Date(y - 1900, m - 1, d, h, min, s).toString());
    }

    public static void main(String[] args) {
        pDate(2037, 3, 29, 2, 0, 0, "Europe/Oslo");
        pDate(2038, 3, 28, 2, 0, 0, "Europe/Oslo");


    }
}

You get the following output:

Sun Mar 29 03:00:00 CEST 2037
Sun Mar 28 01:00:00 CET 2038

And the last one has the same bug. One hour earlier instead of one
hour later. It does not help to use a Calendar object since that one
too builds upon the buggy java.util.Date implementation.

-- 
Bernt Marius Johnsen

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