The command below will start a local Jenkins using the version specificied as first argument (or lts):
./examples/start_docker.sh 2.249.2
The command below allows to build the plugin using maven docker image. This is useful to test building against different Maven/JDK versions. See also SDKMan for a different approach.
docker run -it --rm -v "$PWD":/usr/src/mymaven -v "$HOME/.m2:/root/.m2" -w /usr/src/mymaven maven:3.3-jdk-8 mvn clean package
To resolve some binary compatibility issues JENKINS-48357, the sources from the artifact com.atlassian.httpclient:atlassian-httpclient-plugin:0.23 has been imported in the project to have control over http(s) protocol transport layer. The downloaded sources didn't have any license headers but based on the pom sources are Apache License (see pom in src/main/resources/atlassian-httpclient-plugin-0.23.0.pom)
There is a Jira Cloud test instance that the changes can be tested against, official maintainers are admins that can grant access for testing to PR submitters on a need-to-have basis.
Make sure you have your ~/.m2/settings.xml
configured accordingly - refer to releasing Jenkins plugins.