We run jenkins in a docker container and integrate to a gerrit server using the gerrit-trigger and sonar-gerrit plugins.
Recently we updated our jenkins server from java 8 to java 11, and encountered an error with the sonar-gerrit plugin.

It fails in the post-build step due to a ClassCastException.
The error logged is this:

Recording test results
Getting Sonar Report from: /var/jenkins_home/workspace/cloud-visits/build/sonar/sonar-report.json
Report has loaded and contains 2 issues
ERROR: Build step failed with exception
java.lang.ClassCastException: class [Ljava.lang.Object; cannot be cast to class [Ljava.lang.String; ([Ljava.lang.Object; and [Ljava.lang.String; are in module java.base of loader 'bootstrap')
at org.jenkinsci.plugins.sonargerrit.SonarToGerritPublisher.perform(SonarToGerritPublisher.java:112)
at hudson.tasks.BuildStepCompatibilityLayer.perform(BuildStepCompatibilityLayer.java:79)
at hudson.tasks.BuildStepMonitor$1.perform(BuildStepMonitor.java:20)
at hudson.model.AbstractBuild$AbstractBuildExecution.perform(AbstractBuild.java:741)
at hudson.model.AbstractBuild$AbstractBuildExecution.performAllBuildSteps(AbstractBuild.java:690)
at hudson.model.Build$BuildExecution.post2(Build.java:186)
at hudson.model.AbstractBuild$AbstractBuildExecution.post(AbstractBuild.java:635)
at hudson.model.Run.execute(Run.java:1843)
at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:43)
at hudson.model.ResourceController.execute(ResourceController.java:97)
at hudson.model.Executor.run(Executor.java:429)
Build step 'Post SonarQube issues as Gerrit comments' marked build as failure

We did some digging around and this is a related JDK change that changes the return type of toArray():
https://bugs.openjdk.java.net/browse/JDK-8176893

Attached is a patch file that we have used to make a local build of the plugin that works fine in our environment.