2.1.3 does not build on OpenJDK16

[overratedpro]

I'm sorry to report that the latest release (2.1.3) does not build with docker OpenJDK16 (openjdk:16-jdk-alpine3.12), attaching output from mvn package:

[ERROR] Failures: 
[ERROR]   CacheManagerTest.cacheManagerWithNonReadableJsonFileForKey:159 
Expecting:
 <"">
to start with:
 <"Cache ignored file the-cache-key.json because it cannot be read.
java.nio.file.AccessDeniedException:">

[ERROR]   CacheManagerTest.cacheReturnsNullWhenCachedFileCannotBeRead:148 
Expecting:
 <{}>
to be equal to:
 <null>
but was not.
[INFO] 
[ERROR] Tests run: 121, Failures: 2, Errors: 0, Skipped: 1

[timja]

can't you use the pre-packaged releases?

[overratedpro]

and how do those compile then? :)

[timja]

built on java 8, it's unlikely you're hitting an actual runtime issue, just some test issue most likely

[overratedpro]

Thanks, could you specify the exact version (and flavour)? Asking because I've just ran a quick test on openjdk:8-jdk-alpine3.8 and this does not work due to dependency limitations:

[WARNING] Rule 3: org.apache.maven.plugins.enforcer.RequireUpperBoundDeps failed with message:
Failed while enforcing RequireUpperBoundDeps. The error(s) are [
Require upper bound dependencies error for org.conscrypt:conscrypt-openjdk-uber:2.2.1 paths to dependency are:
+-io.jenkins.plugin-management:plugin-management-library:2.1.2
  +-com.github.tomakehurst:wiremock-jre8:2.27.2
    +-org.conscrypt:conscrypt-openjdk-uber:2.2.1
and
+-io.jenkins.plugin-management:plugin-management-library:2.1.2
  +-com.github.tomakehurst:wiremock-jre8:2.27.2
    +-org.eclipse.jetty:jetty-alpn-conscrypt-server:9.4.30.v20200611
      +-org.conscrypt:conscrypt-openjdk-uber:2.4.0
and
+-io.jenkins.plugin-management:plugin-management-library:2.1.2
  +-com.github.tomakehurst:wiremock-jre8:2.27.2
    +-org.eclipse.jetty:jetty-alpn-conscrypt-client:9.4.30.v20200611
      +-org.conscrypt:conscrypt-openjdk-uber:2.4.0
]
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-enforcer-plugin:3.0.0-M3:enforce (display-info) on project plugin-management-library: Some Enforcer rules have failed. Look above for specific messages explaining why the rule failed. -> [Help 1]

[timja]

Check this: https://ci.jenkins.io/blue/organizations/jenkins/Tools%2Fplugin-installation-manager-tool/detail/master/229/

it will log the versions used

[yabberyabber]

I was having a similar issue and noticed that this build has been cleaned up

Luckily, I found this reference explaining how to build locally https://github.com/jenkinsci/.github/blob/7baf6188c5dbe8f872bd7f4e13e1aaeee0b2e279/CONTRIBUTING.md#run-locally