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https://issues.apache.org/jira/browse/LANG-1791?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18032511#comment-18032511
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Gary D. Gregory edited comment on LANG-1791 at 10/23/25 3:29 PM:
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Hello [~rodche]
Thank you for your report. Feel free to create a PR on GitHub with your
suggested fix and test.
was (Author: garydgregory):
Hello [~Adhip]
Thank you for your report. Feel free to create a PR on GitHub with your
suggested fix and test.
> FastDateFormat behavior changed between 3.0.1 and e.g. 3.18.0 and later
> -----------------------------------------------------------------------
>
> Key: LANG-1791
> URL: https://issues.apache.org/jira/browse/LANG-1791
> Project: Commons Lang
> Issue Type: Bug
> Environment: Linux (Ubuntu 24.04), temurin-17.0.16 JDK, run in
> Toronto.
> Reporter: Igor Rodchenkov
> Priority: Major
>
> Lately, we discovered a bug which is better demonstrate with this test case
> (it's not perfect because always passes in GMT zone, but e.g. in Toronto it
> passes when commons-lang3 v3.0.1 used and fails when v3.18.0 or 3.19.0 is
> used; and yes, in this special case, we have somewhat legacy java code using
> Calendar etc., but that was what broke in our app by this library upgrade,
> which supoosed to be backward compatible):
>
>
> {code:java}
> /*
> * org.apache.commons.lang3.time.FastDateFormat
> * In dateFormatter.format(timeCal), when time was not set explicitly, would
> make e.g.
> * the following timestamps in Toronto at 10 am on 2025-09-17:
> * "2025091714" - UTC, as expected, when using commons-lang3 v3.0.1
> * "2025091710" - EDT, when using commons-lang3 v3.18.0 :(
> */
> @Test
> public void fastDateFormatFormatterUsingCalendarShouldMakeGmtTimestamp() {
> FastDateFormat dateFormatter = FastDateFormat.getInstance("yyyyMMddHH");
> TimeZone timeZone = TimeZone.getTimeZone("GMT");
> Calendar timeCal = Calendar.getInstance(timeZone);
> Date time1 = timeCal.getTime(); //in local time zone
> ZoneId zone = ZoneId.systemDefault();
> ZoneOffset off = zone.getRules().getOffset(time1.toInstant());
> System.out.printf("Time: %s, zone: %s, offset(s): %s\n", time1, zone,
> off.getTotalSeconds());
> String timestamp1 = dateFormatter.format(timeCal); //makes local zone
> timestamp when commons-lang3 v3.18.0 is used.
> Date time = Date.from(Instant.now().minusSeconds(off.getTotalSeconds()));
> String timestamp2 = dateFormatter.format(time); //GMT timestamp
> assertEquals(timestamp2, timestamp1);
> }{code}
>
> I think the bug is in 3.18.0 the FastDatePrinter here -
> {code:java}
> @Override
> public <B extends Appendable> B format(Calendar calendar, final B buf) {
> // do not pass in calendar directly, this will cause TimeZone of
> FastDatePrinter to be ignored
> if (!calendar.getTimeZone().equals(timeZone)) {
> calendar = (Calendar) calendar.clone();
> calendar.setTimeZone(timeZone);
> }
> return applyRules(calendar, buf);
> }{code}
> - note misleading comment, - it's calendar's timeZone is in fact there
> ignored instead of date printer's timeZone!
>
>
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