Why does parsing a date with weekyear return the wrong year?

Question

DateTime time=DateTimeFormat.forPattern("yyyy-ww").parseDateTime("2013-01");

where DateTimeFormat is org.joda.time.format.DateTimeFormat.

When I execute the above, time becomes 2013-12-30T00:00:00.000 what am I doing wrong? Is this a bug? I expect it to be the first week of 2013, not the last.

What value do you expect instead? Why? – Sotirios Delimanolis Jul 15 '16 at 15:19 — Sotirios Delimanolis, Jul 15 '16 at 15:19
The date of the first week of 2013 – Tony Wolff Jul 15 '16 at 15:26 — Tony Wolff, Jul 15 '16 at 15:26
2013-02 gives 2013-01-07 so I would expect 2012-12-31 – Tony Wolff Jul 15 '16 at 15:30 — Tony Wolff, Jul 15 '16 at 15:30

score 3 · Accepted Answer · answered Jul 15 '16 at 15:28

See here.

The w, week of weekyear, pattern letter is meant to be used with x, weekyear. From the javadoc of DateTimeFormat

 x       weekyear                     year          1996
 w       week of weekyear             number        27

Change your pattern to

DateTimeFormat.forPattern("xxxx-ww")

and you'll parse to

2012-12-31T00:00:00.000-08:00

Depending on your Locale, the first week of 2013 started in 2012.

Why does parsing a date with weekyear return the wrong year?

1 Answers1