Migration to Java 21 and Spring Boot 3.4
- Julian Ladisch
Please add any missing hints to this document!
See TC’s approved Officially Supported Technologies / Sunflower document.
Help
Ask on #development Slack channel if a module doesn’t build on Java 21 and/or Spring Boot 3.4.
Jenkinsfile
In Jenkinsfile change the buildNode from java17 to java21:
buildNode = 'jenkins-agent-java21' Dockerfile
In Dockerfile change the container from opendjk17 to openjdk21:
FROM folioci/alpine-jre-openjdk21:latestGitHub Actions
A few projects use a Java in GitHub Actions workflow, check the .github/workflows directory. Upgrade java-version from 17 to 21:
- uses: actions/setup-java@v4
with:
distribution: 'temurin'
java-version: '21'POM Files
If declared, be sure to change the Java version and source/target compilation versions. This can be done under the main properties block:
Note: for this to work, be sure that the source/target versions are not overridden in the maven-compiler-plugin configuration.
Mockito
See https://javadoc.io/doc/org.mockito/mockito-core/latest/org/mockito/Mockito.html#0.3 how to enable instrumentation of Mockito’s inline-mock-maker if it doesn’t work with Java 21.
Spring Boot
Upgrade the spring-boot-starter-parent version to the latest 3.4 version, find the version on https://github.com/spring-projects/spring-boot/tags
This is a milestone version like 3.4.0-M4 or a release candidate version like 3.4.0-RC5 because a final version is not available yet.
Add
to the <repositories> section of pom.xml.
Add
to pom.xml for spring-boot-maven-plugin.
Replace javax.annotation.PostConstruct with jakarta.annotation.PostConstruct.
Add null argument to buildConsumerProperties() and buildProducerProperties() of KafkaProperties (example).
Migrated repositories
Some FOLIO modules and FOLIO libraries have been migrated to Spring Boot 3.4 to demonstrate that only small changes are needed:
Build result: success | |
Build result: success | |
Build result: success | |
https://github.com/folio-org/mod-search/compare/master...julianladisch:mod-search:spring-boot-3.4 | Build result: success |
Build result: success | |
Build result: success |
Why milestone and release candidate versions?
Some FOLIO development teams start Sunflower work before the official Spring Boot 3.4.0 version gets released:
Spring Branch | Initial Release | End of Support |
|---|---|---|
2024-11-21 | 2025-11-21 |
Why snapshot versions?
For spring-cloud-starter-openfeign.
spring-cloud-starter-openfeign is a dependency of folio-spring-base, folio-spring-system-user and most spring based modules. spring-cloud-starter-openfeign 4.2.x is required for Spring Boot 3.4.x, and spring-cloud-starter-openfeign hasn’t published milestone or release candidate versions yet, only 3.4.0-SNAPSHOT versions: https://github.com/spring-cloud/spring-cloud-openfeign/tags
This is low risk because Spring Cloud OpenFeign project is treated as feature-complete.
When upgrade to release versions?
After Spring Boot 3.4.0 has been released and before the module gets released.
What is Spring Boot’s milestone and release candidate history?
v3.3.x:
2024-05-23 v3.3.0
2024-04-19 v3.3.0-RC1
2024-04-05 v3.3.0-M3
2024-02-22 v3.3.0-M2
2024-01-19 v3.3.0-M1
v3.2.x:
2023-11-23 v3.2.0
2023-11-03 v3.2.0-RC2
2023-10-20 v3.2.0-RC1
2023-09-21 v3.2.0-M3
2023-08-24 v3.2.0-M2
2023-07-20 v3.2.0-M1
v3.1.x:
2023-05-19 v3.1.0
2023-05-05 v3.1.0-RC2
2023-04-22 v3.1.0-RC1
2023-04-24 v3.1.0-M2
2023-02-24 v3.1.0-M1
Spring Boot has always been released on the planned date.
Difference between RC and GA
Is there a risk that the devs on the spring project change their minds and some things in the 3.4 RC don't make it into 3.4 GA?
No, RC is feature freeze.
Even if a feature from RC gets removed in GA, most FOLIO modules won’t be affected because usually they don’t use features from the latest minor version.