[jira] [Created] (LANG-1029) FastDateFormat static instance format differently compared to new instance when changing timezone

["Sven Diedrichsen (JIRA)" <ji...@apache.org>]

Sven Diedrichsen created LANG-1029:
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             Summary: FastDateFormat static instance format differently compared to new instance when changing timezone
                 Key: LANG-1029
                 URL: https://issues.apache.org/jira/browse/LANG-1029
             Project: Commons Lang
          Issue Type: Bug
          Components: lang.time.*
    Affects Versions: 3.3.2
            Reporter: Sven Diedrichsen


Static FastDateFormat instances don't recognize default TimeZone changes and thus don't behave equal to newly created instances of FastDateFormat or SimpleDateFormat.

I can imagine people using FastDateFormat like this for performance optimization reasons.

{code:title=Test for difference}
    private static final String DATE_TIME_PATTERN = "dd.MM.yyyy HH:mm:ss";
    private static final FastDateFormat FDF = FastDateFormat.getInstance(DATE_TIME_PATTERN);

    public static void main(String[] args) {

        TimeZone gmtTimeZone = TimeZone.getTimeZone("GMT");

        Calendar date = Calendar.getInstance();
        date.setTimeZone(gmtTimeZone);
        date.set(2014, Calendar.JANUARY, 1, 0, 0 ,0);

        TimeZone backupTimeZone = TimeZone.getDefault();
        TimeZone.setDefault(gmtTimeZone);

        System.out.println("FastDateFormat static:\t\t"+ FDF.format(date.getTime()));
        System.out.println("FastDateFormat instance:\t" + FastDateFormat.getInstance(DATE_TIME_PATTERN).format(date.getTime()));
        System.out.println("SimpleDateFormat instance:\t" + new SimpleDateFormat(DATE_TIME_PATTERN).format(date.getTime()));

        TimeZone.setDefault(backupTimeZone);

    }
{code}
{panel:title=Output}
FastDateFormat static:		01.01.2014 01:00:00
FastDateFormat instance:	01.01.2014 00:00:00
SimpleDateFormat instance:	01.01.2014 00:00:00
{panel}




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