(Back to JSTEP page)

---

JSTEP-11: Use native JPMS module-info.java

Author

Tatu Saloranta (@cowtowncoder)

Version History

• 2025-04-11: Update wrt jackson-module-kotlin
• 2025-04-10: Update wrt javax.money datatype module completion
• 2025-01-18: Updates
• 2025-01-14: Initial version

Background

Jackson 2.x requires Java 8 as the minimum version, and as such cannot build Java module (JPMS) info (module-info.class) via normal build process. Instead, Moditect plug-in is used to create minimally processed version from module-info.java, to be embedded. But while Moditect can produce legal module-info.class, it does not (and probably cannot) validate goodness to same degree as build does. This means that catching invalid module info declarations is difficult and cannot be done during development or build time, or even CI (at least without extensive external tooling).

These problems can be resolved for Jackson 3.0 when the JDK baseline is raised to 17.

Scope

Conversion requires doing following:

1. Copy src/moditect/module-info.java as both src/main/java/module-info.java and src/test/java/module-info.java
2. Remove src/moditect/module-info.java
3. Remove moditect-maven-plugin invocation from pom.xml
4. Modify src/main/java/module-info.java to work for building main artifact (often adding a module dependency or two; possibly needing changes to "upstream" dependency)
5. Modify src/test/java/module-info.java to work for unit tests (may need changes to main artifact module-info.java)

And once full build (./mvnw clean install) works, initial conversion should be complete. Note, tho, that further changes may be needed by "downstream" components once they use full "modularized" build

Status

Overall: completed as of 2025-04-11 as far as feasible -- 1 and only remaining module (jackson-module-scala) unlikely to get completed by Jackson 3.0.0.

Completed

Completed, core

• jackson-annotations
  • https://github.com/FasterXML/jackson-annotations/issues/274
• jackson-core
  • https://github.com/FasterXML/jackson-core/issues/1380
• jackson-databind
  • https://github.com/FasterXML/jackson-databind/issues/4891

Completed, data format modules

• jackson-dataformat-xml
  • https://github.com/FasterXML/jackson-dataformat-xml/issues/701
• jackson-dataformats-text
  • https://github.com/FasterXML/jackson-dataformats-text/issues/531
• jackson-dataformats-binary
  • https://github.com/FasterXML/jackson-dataformats-binary/issues/557 (in-progress)

Completed, base modules

• jackson-modules-base
  • https://github.com/FasterXML/jackson-modules-base/issues/269
• jackson-modules-java8
  • https://github.com/FasterXML/jackson-modules-java8/issues/340

Completed, data type modules

• 'jackson-datatype-joda'
  • https://github.com/FasterXML/jackson-datatype-joda/issues/153
• 'jackson-datatypes-collections'
  • https://github.com/FasterXML/jackson-datatypes-collections/issues/175
• jackson-datatypes-misc'
  • https://github.com/FasterXML/jackson-datatypes-misc/issues/52
  • https://github.com/FasterXML/jackson-datatypes-misc/issues/56

Completed, Providers

• jackson-jaxrs-providers
  • https://github.com/FasterXML/jackson-jaxrs-providers/issues/206
• jackson-jakarta-rs-providers
  • https://github.com/FasterXML/jackson-jakarta-rs-providers/issues/43

Completed, JVM language modules

• jackson-module-kotlin
  • https://github.com/FasterXML/jackson-module-kotlin/issues/887

Completed, other

• jackson-jr
  • https://github.com/FasterXML/jackson-jr/issues/185
• jackson-integration-tests

In-progress

Planned, JVM language modules

• jackson-module-scala
  • NOTE: Scala module does not currently produce module-info.class at all (does it have Automatic-Module-Name?)
  • https://github.com/FasterXML/jackson-module-scala/issues/700 for any improvements (even if no module-info.java)