Add test matrix for different java versions

[jaydeluca]

No description provided.

[zeitlinger]

@jaydeluca I think we don't need to build the release for every version - it has to tests anyways

[zeitlinger]

great!

[zeitlinger]

why not 8, 11?

[jaydeluca]

i couldnt get them to work, can't remember why, let me try again to refresh my memory

[jaydeluca]

theres a bunch of test code that uses switch statements and """...""" text blocks. I can refactor them all if we think it's worth it?

[jaydeluca]

also, JUnit Jupiter 6.0.2 requires Java 17+ to run

[zeitlinger]

why is this needed?

[jaydeluca]

adding the profiles has added some issues to the way some of these other tasks resolve everything.

from:
https://github.com/prometheus/client_java/actions/runs/21207964631/job/61008982563?pr=1781

Error:  Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.14.1:testCompile (default-testCompile) on project prometheus-metrics-exposition-formats: Compilation failure: Compilation failure: 
Error:  /home/runner/work/client_java/client_java/prometheus-metrics-exposition-formats-shaded/target/metrics-exposition-formats/src/test/java/io/prometheus/metrics/expositionformats/ProtobufExpositionFormatsTest.java:[11,45] cannot find symbol
Error:    symbol: class ExpositionFormatsTest
Error:  /home/runner/work/client_java/client_java/prometheus-metrics-exposition-formats-shaded/target/metrics-exposition-formats/src/test/java/io/prometheus/metrics/expositionformats/ProtobufExpositionFormatsTest.java:[13,3] method does not override or implement a method from a supertype

the shaded module's tests need a test-jar dependency that's explicitly excluded from the release profile, so thats why i added the !examples-and-integration-tests to disable them (i assumed that would be ok to skip for testing the release build)

I was also encountering gpg issues both in CI and locally, not sure if this is a "me" thing, but didn't think it was necessary for this test step

[Copilot]

Pull request overview

This pull request adds a test matrix to enable testing across different Java versions (17, 21, and 25) while maintaining Java 8 compatibility for the main codebase. The changes restructure Maven profiles and dependencies to support building and testing on older JDK versions.

Changes:

• Added new GitHub Actions workflow for multi-version Java compatibility testing (Java 17, 21, 25)
• Restructured Maven configuration: moved test dependencies out of profile to global scope, renamed default profile to examples-and-integration-tests (activated only for Java 25+), and created new errorprone profile (activated for Java 21+)
• Added reflection-based compatibility layer in HTTPServerTest for Subject API differences between Java 17 and Java 18+

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
.github/workflows/multi-version-test.yml	New workflow for testing on Java 17, 21, and 25
pom.xml	Restructured profiles and dependencies for multi-version support; added test.java.version property
prometheus-metrics-parent/pom.xml	Moved spotless plugin to java17-plus profile
integration-tests/it-spring-boot-smoke-test/pom.xml	Moved spotless and native-maven-plugin to java17-plus profile
benchmarks/pom.xml	Added compiler args override to prevent ErrorProne inheritance
prometheus-metrics-exporter-httpserver/src/test/java/io/prometheus/metrics/exporter/httpserver/HTTPServerTest.java	Added reflection-based compatibility for Subject API across Java versions
.mise/tasks/build-release.sh	Updated profile references to match renamed profile
.editorconfig	Increased max line length for pom.xml; added configuration for build-release.sh

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