make 'mvn test' work with JDK's < 11

[Peter Moore]

Right now, running ‘mvn test’ with a JDK < 11 will fail with:

[ERROR] Failed to execute goal net.revelc.code.formatter:formatter-maven-plugin:2.20.0:format (default) on project snakeyaml: Execution default of goal net.revelc.code.formatter:formatter-maven-plugin:2.20.0:format failed: Unable to load the mojo 'format' in the plugin 'net.revelc.code.formatter:formatter-maven-plugin:2.20.0' due to an API incompatibility: org.codehaus.plexus.component.repository.exception.ComponentLookupException: net/revelc/code/formatter/FormatterMojo has been compiled by a more recent version of the Java Runtime (class file version 55.0), this version of the Java Runtime only recognizes class file versions up to 52.0
[ERROR] -----------------------------------------------------

This stems from revelc only working with jdk11. Could the execution of revelc be made conditional on the JDK version?

In the attached pom.xml I moved the revelc plugin to a new ‘jdk11_or_greater’ profile that is activated by <jdk>[11,)</jdk> (i.e. all jdk versions greater or equal to 11). With that pom, ‘mvn test’ now works with jdk8. I’m not sure what the revelc plugin does, but I have confirmed that a jdk11 build with that pom will generate revelc related messages in the debug output and apidocs are still generated.

‌

[Andrey Somov]

What is the added value to run under Java 8 ?

You can use docker to run under any JDK. Feel free to check the included scripts (and modify them)

./docker-run-jdk*

‌

[Peter Moore]

We ship our product on JDK 8 and so we test using the JDK that the customer will use. In particular, being able to run the tests with JDK8 would allow catching issues like 573.

[Andrey Somov]

@{6204d7ce35a62a006844789c} I tried to apply the POM, but I get an error:
./mvnw clean install site

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.10.1:compile (default-compile) on project snakeyaml: Fatal error compiling: invalid flag: --release -> [Help 1]

[Andrey Somov]

any progress ?

[Andrey Somov]

No feedback provided