Maven .gitignore template

target is the only rule most projects will ever need. Everything the build produces lands there: compiled classes, generated sources, test reports, the packaged jar or war, and the dependency copies used at test time. It is derived entirely from the project object model and the sources, and it is rebuilt from scratch by a clean build.

The rest of the template exists because the release plugin is unusually messy. Preparing a release rewrites the project file to a release version, tags, then rewrites it again to the next development version, and it keeps backups at each step. pom.xml.tag, pom.xml.releaseBackup, pom.xml.versionsBackup and pom.xml.next are those backups.

release.properties is the state file that lets an interrupted release be resumed. If a release fails halfway, that file is how the plugin knows where it stopped, which makes it genuinely useful locally and completely meaningless to anyone else. Committing it can also confuse a later release attempt.

dependency-reduced-pom.xml is generated by the shade plugin when it builds an uber jar, holding a version of the project file with the shaded dependencies stripped out. buildNumber.properties comes from the build number plugin and .mvn/timing.properties is profiling output. None of the three appear unless the matching plugin is configured, so most projects will never create any of them.

The wrapper jar is where this template differs from its Gradle counterpart. It ignores .mvn/wrapper/maven-wrapper.jar rather than negating it, which reflects the newer wrapper that downloads the jar on first use instead of shipping it. On an older project that still commits the jar, remove that line, otherwise you will untrack the file a clone needs.