feat: Support Jenkins >= 2.475

[rahulsom]

Jenkins 2.475 and Jenkins LTS 2.479.1 introduce a change to the Java Servlet API version and the servlet container support policy.

This takes it from JEE8 to JEE9.
This changes the coordinates of servlet-api to jakarta.

This gradle plugin can be built with JDK 11 but not with JDK 17 which would be required for adding the extra test to JenkinsVersionIntegrationSpec.

Related: JENKINS-73278
Related: jenkinsci/jenkins#9672

Testing done

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[sghill]

Thanks!

[basil]

Looking at 7387a74 it seems this was released in v0.53.0-rc.2 and
v0.52.0-rc.3 but not 0.52.0 itself? Can this please be released in a non-release candidate build so I can consume it from gradle-plugin?

[sghill]

@basil 0.53.0 is out now. Releases page will be updated later today.

A tooling issue led to 0.52.0-rc.3 being created after 0.52.0 was already released. This has since been fixed.

[basil]

@rahulsom This PR appears to be necessary but not sufficient to support Jenkins ≥ 2.475 and Java 17, as demonstrated in the minimal conversion in jenkinsci/text-finder-plugin#256 which fails test compilation with

> Compilation failed; see the compiler output below.
  /home/jenkins/agent/workspace/lugins_text-finder-plugin_PR-256/src/test/java/hudson/plugins/textfinder/test/TestWriteFileBuilder.java:41: error: cannot access ServletException
      public static class DescriptorImpl extends BuildStepDescriptor<Builder> {
                    ^
    class file for jakarta.servlet.ServletException not found
  Note: Some input files use or override a deprecated API.
  Note: Recompile with -Xlint:deprecation for details.
  1 error

[rahulsom]

I checked out that branch and ran this

./gradlew dependencyInsight --configuration compileClasspath --dependency servlet-api

It does show

jakarta.servlet:jakarta.servlet-api:5.0.0
+--- compileClasspath
\--- org.jenkins-ci.main:jenkins-bom:2.479.1
     +--- compileClasspath
     \--- org.jenkins-ci.main:jenkins-core:2.479.1
          \--- compileClasspath

But this doesn't

./gradlew dependencyInsight --configuration testCompileClasspath --dependency servlet-api

@sghill Do you think servlet-api needs adding here

[sghill]

Yes, agree with adding it to testCompileOnly

[basil]

I think the issue is likely the inclusion of an old test harness that bundles Jetty 10 and EE 8. For 2.479.1 LTS and Java 17 the latest test harness should be used, which bundles Jetty 12 and EE 9.