Apache Maven vs RubyGems.org

Apache Maven is a free build tool for Java projects. It uses a project object model, or POM, and plugins to manage compilation, testing and documentation through a uniform build system. Maven manages dependencies, including transitive dependencies and automatic updates, and can download them from a central repository. Project metadata can produce outputs such as JARs, WARs and distributions. Maven can also generate project information, including changelogs, cross-referenced sources, dependency lists and unit test reports. Java or scripting-language plugins extend it, and it can work with source control systems such as Subversion or Git to manage tag-based releases. It runs on Windows, macOS and Linux. Maven 3.10 and later requires JDK 8 or above to execute, while toolchains can target other JDK versions. Its project layout is opinionated, so projects with unusual structures that cannot be reorganized may have to give up some Maven features or Maven itself. The software is distributed under Apache License 2.0; its listed plan costs nothing.

RubyGems.org has no write-up on Specifiction yet; its figures are above.