[FEATURE] Add Support to Compile Plugin with JDK 24

[jass95]

The OpenSearch plugin should support being compiled with JDK 24, since OpenSearch versions 3.2.0 and above bundle JDK 24.

Although OpenSearch > 3.2.0 still supports JDK 21, and JDK 21 remains a Long-Term Support (LTS) release, adding compatibility for JDK 24 ensures that the plugin can be built using the same JDK that OpenSearch ships with.

Request:
Please update the build configuration so the plugin can be compiled additionally with JDK 24.

Thanks!

[kumargu]

thanks @jass95

One reason we didn't focus on JDK-24 was because JDK-24 is not LTS. We can definitely add support JDK-24 but it it would not be as trivial as changing jvm options (the way Opensearch works) for this plugin. This plugin relies on Java Panama API and some of the Panama APIs have changed between JDK-21 & JDK-24.

[jass95]

I understand the rationale for preferring JDK 21 due to its LTS status and agree that simply changing the Java version isn’t enough.

However, downgrading the entire OpenSearch instance to JDK 21 could potentially affect other plugins that rely on the bundled JDK 24. Supporting JDK 24 for this plugin would allow it to work seamlessly out-of-the-box with OpenSearch’s bundled JDK and the official Docker image, without impacting other plugins or the overall runtime environment.

[kumargu]

thanks @jass95, understood.

We will come back on this to evaluate how we can build support for JDK-24. We are currently working on giving final touches to this plugin to make is launch ready, so we are kinda swamped right now. We can get a JDK-24 compatible version ready by end of December.

Me personally wanted to move to Java-24 + , because the Panama APIs are stabilized and Java ciphers are 2x faster. Which is why we had earlier made the change #36 to bump the version to JDK-24, but a lot of customers (and AWS :)) won't want to bump to a non-LTS version because version bumps are pain, and we had to revert this PR.

The PR will give you hints what essentially we need to make changes to make it compatibility both ways. Also welcomed for any PR contribution.