Bump the minimum Java version?

[FDelporte]

At this moment, Pi4J V2 is built with Java 11 as the target, see https://github.com/Pi4J/pi4j-v2/blob/develop/pom.xml#L252

        <!-- JAVA COMPILER VERSIONS -->
        <java.version>11</java.version>
        <maven.compiler.source>${java.version}</maven.compiler.source>
        <maven.compiler.target>${java.version}</maven.compiler.target>

This means we miss out on many newer Java language and runtime improvements. Future versions will also make it easier to call C code to interact with the GPIOs, like JEP 454: Foreign Function & Memory API.

Do you agree we should move forward and bump Pi4J to a higher Java version? If so, which one?

[johanvos]

Is following the Tip & Tail approach (https://openjdk.org/jeps/14) an option here? You can branch out 11 here, and only add things to it when there are critical (security) issues, while using a later JDK version (21/23) on the tip?

[FDelporte]

Thanks for the tip! Will take a look at this...

[eitch]

Basically i have no issue back porting fixes. Lately most changes were new features and thus wouldn't have been backported anyhow. But the idea is definitely valid and i would always backport them, if needed.

[taartspi]

I selected the LTS. As the code base is used in various projects/products i think we owe the community the level with the most stable support

[FDelporte]

Last weeks I have been experimenting a bit with Java on 32-bit Raspberry Pi (for older boards). As far as I know, only Java 8 and 11 are available. So if we bump to a higher version, we will exclude these boards from newer Pi4J features later.

This is not a deal-breaker as we still will have the latest stable 2.X.Y release for those use-cases. But in that case, we will need to clearly document this.

[taartspi]

I saw u made v3.0 for the java 21. That works well for the users. We need to also add some doc detail on how we implement fixes needed in both versions.

[FDelporte]

It's only a first step, as an experiment to see if build etc. works... If we proceed like this, fixes will only applied in new V3 versions. Except for critical/security issues, these would be "backported".