What is the policy for dependencies that require Java 21?

[Legioth]

As we're seeing now with jOOQ 3.20, lack of support for Java 17 means that you're booted from Spring Boot's own dependency management (or in that case stuck at an old version). Will the same also be the case for dependencies that get their version number directly from Spring Initializr? I'm thinking this could be different since Initializr has an explicit Java version selector and could thus offer feedback to the user if they are about to create an unsupported combination. Or maybe you're even about to drop Java 17 from Initializr in the foreseeable future based on what was mentioned in the Spring Framework 7 announcement discussion about Java 17 being tolerated but not recommended?

I'm asking because Vaadin is evaluating the possibility of having Java 21 as the baseline for the upcoming major version that would be built for Spring Boot 4. It's a tough choice for other reasons but it would probably be a deal breaker if Vaadin could no longer be available in Spring Initializr.

[mhalbritter]

Hello,

right now, there's nothing in the metadata which could specify that Vaadin only works with Java 21 and up. That's something we want to tackle in spring-io/initializr#958.

Until this is resolved, it means that users can select (a future Java 21 baseline) Vaadin and Java 17 in the UI (start.spring.io, or IDE integration, ...). In that case we would automatically upgrade them to Java 21, and put something in the HELP.md file.

[Legioth]

In that case we would automatically upgrade them to Java 21

Not sure I understand how that would happen if there's no metadata for that? Or is this a vision for how it could work once support for that metadata has been introduced?

[mhalbritter]

We hardcode it in Java code. If (a Java 21 baseline) Vaadin is selected, Java is upgraded to Java 21.

The downside is that the user only realizes this when the project is downloaded. It's not reflected in the UI.

[lukaseder]

right now, there's nothing in the metadata which could specify that Vaadin only works with Java 21 and up. That's something we want to tackle in spring-io/initializr#958.

Will it be possible to provide meta data also for artifacts that aren't available from Maven Central? In the case of jOOQ, specifically, the baseline is really still Java 8 for the commercial editions, which can be used easily with Spring Boot just by replacing Spring Boot's managed org.jooq dependency by org.jooq.pro-java-8, for example: https://blog.jooq.org/how-to-use-jooqs-commercial-distributions-with-spring-boot/

[mhalbritter]

We'd only manage metadata for dependencies directly available on start.spring.io. In the jOOQ case, with a Java 21 baseline, I guess we'd add java-version: 21 in the metadata.

[mhalbritter]

Or maybe you're even about to drop Java 17 from Initializr in the foreseeable future based on what was mentioned in the Spring Framework 7 announcement discussion about Java 17 being tolerated but not recommended?

I don't think this will happen. We've had Java 8 on there for ages with Boot 2.x.

[Legioth]

Right. I was only considering https://start.spring.io/ that currently doesn't offer anything older than Spring Boot 3.3.9.