Jackson 3.0

[Ullrich Hafner]

Another core library that we are using extensively in Jenkins is Jackson. There is a new major release with breaking changes available as well: 

https://github.com/FasterXML/jackson/wiki/Jackson-Release-3.0

We use Jackson directly in core, plugins use it via the Jackson 2 API plugin. What are the plans here? Does it make sense to create a Jackson 3 API plugin so that plugins can migrate to Jackson 3 if they want? Or will this be a conflict when Jenkins core does not update its own dependency? 

[Winter, Markus]

We already have an api plugin for Jackson 3

https://plugins.jenkins.io/jackson3-api/

Afaik we don't use jackson in core

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From: jenkin...@googlegroups.com <jenkin...@googlegroups.com> on behalf of Ullrich Hafner <ullrich...@gmail.com>
Sent: Tuesday, February 24, 2026 9:29 AM
To: Jenkins Developers <jenkin...@googlegroups.com>
Subject: Jackson 3.0

 

Another core library that we are using extensively in Jenkins is Jackson. There is a new major release with breaking changes available as well: 

https://github.com/FasterXML/jackson/wiki/Jackson-Release-3.0

We use Jackson directly in core, plugins use it via the Jackson 2 API plugin. What are the plans here? Does it make sense to create a Jackson 3 API plugin so that plugins can migrate to Jackson 3 if they want? Or will this be a conflict when Jenkins core does not update its own dependency? 

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[Valentin Delaye (jonesbusy)]

Plugin transition will take some time but already happen.

Example is flyway-api that will require jackson3 because the upstream dependency now require it (https://documentation.red-gate.com/fd/release-notes-for-flyway-engine-179732572.html)

Cheers,

[Valentin Delaye (jonesbusy)]

Note: Jackson 2.x and Jackson 3.x can exists in parallel 

They both package jackson-annotations but with different version

Jackson 2.20 (our current version) package jackson-annotations:jar:2.20

Jackson 2.21 (next version, LTS apparently) package jackson-annotations:jar:2.21

Jackson 3.0 package jackson-annotations:jar:2.20

Jackson 3.1 (our current version) package jackson-annotations:jar:2.21

If a plugin depends (direct or transitive) different jackson-annotations can cause upper bound issue.

But apparently PCT discovered also java.lang.ExceptionInInitializerError: Exception java.lang.NoClassDefFoundError: com/fasterxml/jackson/annotation/JsonSerializeAs

When updating to Jackson 2.21 I cannot reproduce the issue (with Junit plugin for example)

So if bom https://github.com/jenkinsci/bom/pull/6432 pass I would suggest to upgrade to Jackson 2.21.1

We would need to keep jackson-annotations aligned if they change

[Valentin Delaye (jonesbusy)]

We might also have some issue (or just class duplicate) with jackson-dataformat-xml. Internally it uses stax2-api and woodstox-core which we package directly on Jackson2 API plugin.

For the moment for XML format we don't have consumer yet (PR in draft: https://github.com/jenkinsci/jackson3-api-plugin/pull/36)

For other format it's not an issue because we already have API plugin

TOML --> No transitive dependency

YAML --> snakeyaml or snakeyaml-engine (we have API plugin for both)

JSON --> for datatype (jackson-datatype-json-org) that uses json and we jave json-api plugin (no consumer yet for Jackson3)

Other module like jackson-modules-java8 are directly integrated in jackson-database (since it require Java17)

I would suggest to keep XML on hold until we migrate or have the need for a first consumer with XML serialization