Don't Repeat Yourself in Maven POMs; Use Jcabi-Parent

Maven is a build automation tool mostly for Java projects. It’s a great tool, but it has one important drawback that has motivated the creation of similar tools, like Gradle and SBT. That weakness is its verbosity of configuration. Maven gets all project build parameters from pom.xml, an XML file that can get very long. I’ve seen POM files of 3,000-plus lines. Taking into account 1) recent DSL buzz and 2) fear of XML, it’s only logical that many people don’t like Maven because of its pom.xml verbosity.

But even if you’re an XML fan who enjoys its strictness and elegance (like myself), you won’t like the necessity to repeat yourself in pom.xml for every project. If you’re working on multiple projects, code duplication will be enormous. An average Java web app uses a few dozen standard Maven plugins and almost the same number of pretty common dependencies, like JUnit, Apache Commons, Log4J, Mockito, etc. All of them have their versions and configurations, which have to be specified if you want to keep the project stable and avoid Maven warnings. Thus, once a new version of a plugin is released, you have to go through all pom.xml files in the projects you’re working on and update it there. You obviously understand what code duplication means. It’s a disaster. However, there is a solution.

jcabi-parent is a very simple Maven dependency with nothing inside it except a large pom.xml with multiple pre-configured dependencies, profiles, and plugins. All you need to do in order to reuse them all in your project is define com.jcabi:parent as your parent POM:

<project xmlns="https://maven.apache.org/POM/4.0.0"
  xmlns:xsi="https://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="https://maven.apache.org/POM/4.0.0
    https://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <parent>
    <groupId>com.jcabi</groupId>
    <artifactId>parent</artifactId>
    <!-- check the latest version at https://parent.jcabi.com -->
    <version>0.32.1</version>
  </parent>
  [...]
</project>

That’s all you need. Now you can remove most of your custom configurations from pom.xml and rely on defaults provided by jcabi-parent. Its pom.xml is rather large and properly configured. Multiple projects depend on it, so you can be confident that you’re using the best possible configuration of all standard plugins.

Here are a few examples of pom.xml from projects that are using jcabi-parent (you can see how compact they are): Xembly ReXSL jcabi-http Qulice