Gone are the days of using the SimpleDateFormat to format your dates and times to a nice string. Enter DateTimeFormatter which produces the same result but has a couple nuances which tripped us up at first.
One of the most frustrating problems proved to be with how the DateTimeFormatter actually works. When trying to format an Instant using the formatter shown in the below example:
Running this would cause an error and produce an extremely ambiguous stack trace:
Turns out this problem occured because the formatter wasn’t given a Zone when it was initialized so it threw a really unhelpful and seemingly irrelevant exception. This is resolved by adding the following to DateTimeFormatter:
Another problem we had was trying to figure out how you specify what format you want an offset in. The Java Docs say you should use x, X or Z to specify a zone-offset but then give multiple different examples of what it will produce….: +0000; -0800; -08:00;
We couldn’t figure out how you explicitly tell it to give you an offset with a colon in (+02:00) as opposed to one without (+2000).
If you want on offset with a colon using x or X then you’ll need to use three to get +02:00 (that’s xxx or XXX) and for Z for you’ll need 5! (ZZZZZ)