ZonedDateTime format and parsing exception

I have a problem with parsing zoned date time:

DateTimeFormatter format = DateTimeFormatter.ofPattern("yyyy-MM-ddzhh:mm");
ZonedDateTime.parse(s, formatter);

and error:

java.time.format.DateTimeParseException: Text ‘2022-05-24UTC12:15’
could not be parsed at index 10

whats wrong with this code ?


>Solution :

tl;dr – You have the wrong pattern…

The character z is not able to parse "UTC" because UTC is a time-zone ID while zcan only parse time-zone-names according to the JavaDocs of java.time.DateTimeFormatter, here’s the relevant part of the docs:

Symbol  Meaning                     Presentation      Examples
------  -------                     ------------      -------

V       time-zone ID                zone-id           America/Los_Angeles; Z; -08:30
z       time-zone name              zone-name         Pacific Standard Time; PST


That means you have to parse it using the character V, but you will have to put two of them (VV) or you will get a nice IllegalArgumentException with the following message:

java.lang.IllegalArgumentException: Pattern letter count must be 2: V

This all boils down to the following pattern:

DateTimeFormatter format = DateTimeFormatter.ofPattern("uuuu-MM-ddVVHH:mm");

which will be able to parse an input like "2022-05-24UTC12:15".

Unfortunately, the docs don’t mention if UTC is actually an id or a name. Consider GMT, which also defines a time zone with an offset of 0 hours. Your current pattern (the one with a single z) would have parsed the input "2022-05-24GMT12:15", because GMT is considered a time-zone name.

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