Change default textual serialization of `java.util.Date`/`Calendar` to include colon in timezone offset

(for background, see #1624 and #1744)

So. While older JDK versions (up to JDK 7) always wrote timezone offset, if any, without colon, like:

+0000

ISO-8601 specification expects minute/hour part to be separated by a colon like

+00:00

While #1744 added an option to enable this behavior, it has not been default for Jackson. Let’s change it in 2.11.

A note on implementation: a new SerializationFeature setting was briefly considered, but wiring of such setting to be used proved difficult. Users can still use method in StdDateFormat

[jocull]

This isn’t clearly documented at all, but after digging through the source code I figured out what you need to do to go back to the old behavior:

final ObjectMapper mapper = JsonMapper.builder()
        .defaultDateFormat(new StdDateFormat().withColonInTimeZone(false)) // <<<<
        .build();

Hope that helps someone else. It’s really difficult to get to these everywhere in your code (and shared libraries!) that it might exist. It also means that doing dependency alignment for things like security reasons (e.g. https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-28491 ) is extremely difficult.

[cowtowncoder]

Thank you for sharing this @jocull. Configurability of date/time handling is quite problematic, alas, both because of variety of differences across platforms and because Java has a few alternatives (“old” JDK, newer Java 8, Joda). And date/time handling is a huge swamp in and of itself, as a domain.

This is known as a problem domain so there have been plans:

https://github.com/FasterXML/jackson-future-ideas/wiki/JSTEP-5

to try to address settings, defaults, configurability. Currently no one has time to tackle this one, unfortunately.