Modernize the plugin to java 11

[AayushSaini101]

Modernize the plugin to java 11.

[MarkEWaite]

The most recent parent pom no longer requires java.level. I've updated the document to show that correction.

Suggested change

<java.level>8</java.level>

[MarkEWaite]

Thanks very much!

When I use your change, there is a test that fails if I run mvn clean verify. I believe that the test failure can be resolved by using the plugin bill of materials as described in the Contributing to Open Source document and in the pre-release of the tutorial. Would you like to make that change in the pull request to use the plugin bill of materials?

Would you also be willing to add a Jenkinsfile in the pull request so that a job will be available on ci.jenkins.io to monitor this repository?

[MarkEWaite]

@AayushSaini101 I'd be very grateful if you'd be willing to experiment with the tutorial that is being assembled from the "Contributing to Open Source" document. The tutorial pull request is available at jenkins-infra/jenkins.io#4806 .

When the pull request build completes, a preview of the tutorial will be available at https://deploy-preview-4806--jenkins-io-site-pr.netlify.app/doc/developer/ in the section labeled "Improve a Plugin - Tutorial". We expect that the tutorial will have completed review and will be live on https://www.jenkins.io/doc/developer/ before the end of September 2022.

[AayushSaini101]

Thanks very much!

When I use your change, there is a test that fails if I run mvn clean verify. I believe that the test failure can be resolved by using the plugin bill of materials as described in the Contributing to Open Source document and in the pre-release of the tutorial. Would you like to make that change in the pull request to use the plugin bill of materials?

Would you also be willing to add a Jenkinsfile in the pull request so that a job will be available on ci.jenkins.io to monitor this repository?

@MarkEWaite Thank you very much Sir for reviewing my PR. When I run mvn clean verify. All the test cases passed successfully. Including the <java.level>8</java.level> as well excluding the <java.level>8</java.level>.

[MarkEWaite]

Thanks for sharing the example. I see the same success on Windows as you see. When I run the tests on a Red Hat Enterprise Linux 8.6 with Java 11.0.16.1, I see the test failure. When I run on a Debian machine, I don't see the test failure. I can't explain why that test would be platform specific. That is quite surprising.

Do you mind if I push the bill of materials change to this branch as a check to confirm that resolves the issue that I am seeing?

The removal of java.level is optional. I suspect it won't be made mandatory for at least a few more releases of the parent pom. No objection from me if you leave it in, though there will be a future release of the parent pom that likely mandates the removal of the java.level property.

[AayushSaini101]

Sure, sir, You can push the bill of materials.