Change JDK baseline for Jackson 3.0 from Java 8 to Java 17

[cowtowncoder]

Describe your Issue

As per title, Jackson 3.0 need not (and should not) keep JDK baseline as Java 8.
We should pick a support LTS version to use as the new base.

We have a choice to make; currently likeliest choices are:

• Java 17 (for maximal support for existing user base)
• Java 21 latest and greatest

We can decide on this via separate discussion; this issue is for tracking actual change.

EDIT: Discussion here: FasterXML/jackson-future-ideas#73

[pjfanning]

My opinion is that libs ideally support the max number of Java versions. Multi-Release jar support is there to help us optimise support for different Java versions.

[JooHyukKim]

Found dup issue #3946

[JooHyukKim]

Which JDK version do you have in mind, with multi-release jar strategy @pjfanning?

[cowtowncoder]

I would prefer not having to use MR for anything, personally. But if we must for something I guess we can try figuring it out.

But even if we do, we need to set up minimum baseline and I think Java 8 should be left for Jackson 2.x. So the question remains.
But let's have discussion/vote on

FasterXML/jackson-future-ideas#73

[cowtowncoder]

Quick suggestion: unless anyone objects, I could work on increasing baseline first to JDK 17 (wrt CI). And then if (but only if) decision is made to go to JDK 21 make further changes. This allows finding possible issues wrt change of baseline and tackling most of complexity, regardless of the ultimate decision on exact baseline JDK to use.

[cowtowncoder]

Note on work for initial JDK 17 update (which may or may not be the last change, depending on discussions)

Core

• jackson-annotations: not to be changed (remains Java 8)
• jackson-core: Update Java baseline to Java 17 [databind#4820] jackson-core#1367 (merged)
• jackson-databind: Fix #4820: Change JDK baseline for Jackson 3.0 from Java 8 to Java 17 #4824 (merged)

Jackson-jr

• jackson-jr: Update minimum Java version to 17 (databind#4820) jackson-jr#178 (merged)

Data formats

• jackson-dataformats-binary: Update Java baseline to Java 17 [databind#4820] jackson-dataformats-binary#531 (merged)
• jackson-dataformats-text: Update Java baseline to Java 17 [databind#4820] jackson-dataformats-text#515 (merged)
• jackson-dataformat-xml: Update Java baseline to Java 17 [databind#4820] jackson-dataformat-xml#690 (merged)

Data types

• jackson-datatypes-collections: Update Java baseline to Java 17 [databind#4820] jackson-datatypes-collections#169 (merged)
• jackson-datatypes-misc: Update Java baseline to Java 17 [databind#4820] jackson-datatypes-misc#50 (merged)
• jackson-datatype-joda: Update Java baseline to Java 17 [databind#4820] jackson-datatype-joda#150 (merged)

Other modules

• jackson-modules-base: Update Java baseline to Java 17 [databind#4820] jackson-modules-base#261 (merged)
• jackson-modules-java8: Update Java baseline to Java 17 [databind#4820] jackson-modules-java8#332 (merged)

JVM langs:

• jackson-module-kotlin: Update minimum Java baseline from 8 to 17 (databind#4820) jackson-module-kotlin#863 (merged)
• jackson-module-scala: Update 3.0 (master) build, CI to use Java 17 baseline jackson-module-scala#696 (merged)

Providers

• Jakarta-RS provider: Update Java baseline to Java 17 [databind#4820] jackson-jakarta-rs-providers#38 (merged)
• JAX-RS provider: Implement [databind#4820]: Java 17 baseline jackson-jaxrs-providers#202 (merged)

[maxandersen]

Go for 17 please otherwise Quarkus, spring and lots of others will be stuck on older Jackson and we'll be all stuck maintaining old code.

Unless you know of some specific feature in java 21 that Jackson just can't function without and not support from Java 17 then please go for 17.

[JooHyukKim]

Your vote + opinion on FasterXML/jackson-future-ideas#73 would be great @maxandersen !

[JooHyukKim]

Data types

• jackson-datatypes-collections: Update Java baseline to Java 17 [databind#4820] jackson-datatypes-collections#169
• jackson-datatypes-misc: Update Java baseline to Java 17 [databind#4820] jackson-datatypes-misc#50
• jackson-datatype-joda: Update Java baseline to Java 17 [databind#4820] jackson-datatype-joda#150