Why Joda DateTimeFormatter cannot parse timezone names ('z')

Question

Zone names: Time zone names ('z') cannot be parsed.

Therefore timezone parsing like:

System.out.println(new SimpleDateFormat("EEE MMM dd HH:mm:ss z yyyy").parse("Fri Nov 11 12:13:14 JST 2010"));

cannot be done in Joda:

DateTimeFormatter dtf = DateTimeFormat.forPattern("EEE MMM dd HH:mm:ss z yyyy");
System.out.println(dtf.parseDateTime("Fri Nov 11 12:13:14 JST 2010"));
//Exception in thread "main" java.lang.IllegalArgumentException: Invalid format: "Fri Nov 11 12:13:14 JST 2010" is malformed at "JST 2010"
//at org.joda.time.format.DateTimeFormatter.parseDateTime(DateTimeFormatter.java:673)

I just wanted to say "F#$% JodaTime!" Okay, not really; it's saved my butt more than a few times. But I REALLY wish they would update their documentation. I spent an hour trying to figure out why this wasn't working. The Javadoc for DateTimeFormat has "z -- time zone text -- Pacific Standard Time; PST". But then, a few paragraphs later on the same page, "Zone names: Time zone names ('z') cannot be parsed." Way to go JodaTime... put it in the small print. No big deal. I just lost 5 years of my life and most of my hair. ;) — The Awnry Bear
@TheAwnryBear - and ... hopefully ... learned a couple of lessons: 1) that timezone abbreviations are EVIL, and 2) that you need to read the javadoc properly :-). — Stephen C
Hehe, agreed Stephen. :) I tend to skimp, which works 95-99% of the time... then you run into situations like with the Joda docs. :P — The Awnry Bear

Stephen C Stephen C · Accepted Answer · 2010-12-21T10:54:41

I think that the reason is that 'z' timezone names are conventional (not standardized) and ambiguous; i.e. they mean different things depending on your country of origin. For example, "PST" can be "Pacific Standard Time" or "Pakistan Standard Time".

If you are interested, this site has a listing of a large number of timezone names. It is not difficult to spot cases where there is ambiguity.

Why Joda DateTimeFormatter cannot parse timezone names ('z')

3 Answers