Reproducible builds

[basil]

https://reproducible-builds.org explains the reasons why reproducible builds are desirable. Some known issues related to reproducible builds:

• project.build.outputTimestamp is not configured as recommended in https://maven.apache.org/guides/mini/guide-reproducible-builds.html
• https://maven.apache.org/guides/mini/guide-reproducible-builds.html notes that maven-release-plugin version 3.0.0-M1 or later will automatically update the project.build.outputTimestamp property in pom.xml during the release in the same commit that updates version but that "if you have a custom release process tooling, you'll need to add the feature to your release tooling." https://github.com/jenkinsci/incrementals-tools is missing this feature.
• Use of Properties#store (e.g., in Stapler) adds timestamps to every generated resource file — though perhaps this could be worked around by specifying -Djava.properties.date on recent Java versions or using a custom Writer that chomps comment lines
• JAR and JPI artifacts created by maven-hpi-plugin do not call MavenArchiver#configureReproducibleBuild as recommended in https://s.apache.org/reproducible-builds
• Even with an explicit source and target defined, each major JDK version changes the generated bytecode
• https://maven.apache.org/guides/mini/guide-reproducible-builds.html notes that maven-javadoc-plugin requires <notimestamp>true</notimestamp> configuration in <pluginManagement> for use both from plugins and reports; this may or may not be an issue in Jenkins plugin builds
• Different line breaks on Unix versus Windows systems are a common problem, which may or may not apply to Jenkins plugin builds

There may be additional issues beyond what is listed above. Further investigation is needed to determine how to achieve this goal.