[REFACTOR] Migrate to Java 11

[toddbaert]

Based on community feedback and communication with known adopters, we are now able to move to Java 11.

This migration mostly benefits us as maintainers, since it enables new language features and tooling.

Requirements:

• update source and target versions for maven-compiler-plugin
• update to use Java 11 language features
  • there might be some helpful tooling for this
  • recommend not changing any tests during "first pass" to make sure no refactors cause undetected regressions
  • no functional changes should be made simultaneously, only refactors and new API usages
• update any tooling pinned to old versions for Java 8 compatibility

Note:

Pending discussion of the technical committee We may choose to release this as a 2.0.

[aepfli]

we might also want to add a module-info.java?

[jarebudev]

happy to pick this one up

[aepfli]

@jarebudev i this ticket to you, happy coding ;)

[chabala]

What would be the effort to move back to Java 8? I can't advocate for using anything that doesn't run on Java 8 as a minimum.

[aepfli]

Estimating the effort is hard, this ticket was done 6 months ago, and a lot has happened in the meantime. We can not say for sure if certain language features have been used already, and most of the tooling does not support java 8 either.

The question is also, who wants to work on this, i do not see a lot of benefit in still supporting java 8. But if there is a contribution, with minimal to none impact to our tooling, and easy feasibility, I do not see a problem. But this is the moment i pass the ball back to you, most likely those efforts in investigation would need some kind of active collaboration ;).

depending on your needs maybe v1.14.2 is still enough - the last java 8 release. we could also open an own branch, where somebody could add security updates - but again the question who will maintain it.

[chabala]

and most of the tooling does not support java 8 either

Could you say anything more specific about this?

Do you have any insight around the drive for using Java 11? It would be a shame to spend effort getting this working on Java 8 again for someone to wander by in six months and want to force an upgrade to Java 17 arbitrarily.

[aepfli]

To be honest, java 17 is definitely on the map in the Future. All the tooling in the newest version have java 17 as a baseline. JUnit, assertj, etc.

So java 17 will be for sure coming in the future. I am not sure if somebody in the community currently wants to maintain an additional java 8 stream.

Furthermore we are already working on V2 which will most likely utilize JPMS functionality to allow splitting API and SDK, which will be bound to at least java 9.

If you/your company wants to move forward with this, I suggest to propose this as a separate issue - not a lot of people are following this topic.

Here is the initial discussion we had to change the baseline - https://github.com/orgs/open-feature/discussions/425