Update source/target to Java17

[yaauie]

Release notes

[rn: skip]

What does this PR do?

Updates the source/target java for the main project to Java 17

Why is it important/What is the impact to the user?

No user impact; we already enforce Java17 as a runtime minimum via the JVM Options Parser, which is still compiled with a source/target of Java11.

For developers, this will allow us to use features from Java 17.

Checklist

• My code follows the style guidelines of this project
• [ ] I have commented my code, particularly in hard-to-understand areas
• [ ] I have made corresponding changes to the documentation
• [ ] I have made corresponding change to the default configuration files (and/or docker env variables)
• [ ] I have added tests that prove my fix is effective or that my feature works

How to test this PR locally

• build it
• try to run it with Java 17, and observe that it works
• set LS_JAVA_HOME to Java 11, and observe the same clear refusal to run

[github-actions]

🤖 GitHub comments

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Just comment with:

• run docs-build : Re-trigger the docs validation. (use unformatted text in the comment!)

[mergify]

This pull request does not have a backport label. Could you fix it @yaauie? 🙏
To fixup this pull request, you need to add the backport labels for the needed
branches, such as:

• backport-8./d is the label to automatically backport to the 8./d branch. /d is the digit.
• If no backport is necessary, please add the backport-skip label

[donoghuc]

Is this just for 9.2? Or does it apply to all of 8 and 9?

[elastic-sonarqube]

Quality Gate passed

Issues
0 New issues
0 Fixed issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
No data about Duplication

See analysis details on SonarQube

[yaauie]

Is this just for 9.2

I've added the backport-skip label. I don't see a reason to backport this, unless we need to backport a fix that uses java17+ features.

My primary motivation is tackling a bunch of the pre-requisites or also-founds for a different effort to make that effort easier to review.

[donoghuc]

Cool. thanks!

[elasticmachine]

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• Commit: 6953ead