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

Question

From DateTimeFormatter javadoc:

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)

Answer 1

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.