[LANG-13] [lang] DateUtils.truncate() is off by one hour when using a date in DST switch 'zone'

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.0
• Fix Version/s: 2.1
• Component/s: lang.time.*

Environment

Operating System: All
Platform: All

• Bugzilla Id: 25560
• Assignee: Unassigned
• Reporter: Joachim Hagger
• Created: 16/Dec/03 18:44
• Updated: 16/Dec/09 08:51
• Resolved: 16/Dec/09 08:51

Description

Try this using a Central European TimeZone:

import java.util.Calendar;
import org.apache.commons.lang.time.DateUtils;

Calendar cal = Calendar.getInstance();
cal.set(Calendar.MONTH, Calendar.MARCH);
cal.set(Calendar.YEAR, 2003);
cal.set(Calendar.DAY_OF_MONTH, 30);
cal.set(Calendar.HOUR_OF_DAY, 5);
cal.set(Calendar.MINUTE, 0);
cal.set(Calendar.SECOND, 0);
Date date_20030330 = cal.getTime();

Date expDate = DateUtils.truncate(date_20030330, Calendar.DATE);
System.out.println(expDate.toString());

-> Sat Mar 29 23:00:00 MET 2003 instead of Sun Mar 30 00:00:00 MET 2003

If the calendar instance represents a date AFTER the daylight savings time
switch and will be truncated to a time BEFORE the daylight savings time switch,
then the resulting date is wrong. (Daylight savings time was Sun Mar 30 02:00:00
resetting to 01:00.00.) Might also happen when rounding up dates over the
daylight savings time switch...