Avoiding repetitive groupIds and versions, and inheriting from the parent POM

In a multimodule Maven project, most of the modules (if not all) share the same groupId and the version elements. In that case, you can avoid adding version and groupId elements to your application POM file, as those will be automatically inherited from the corresponding parent POM.

If you look at axis2-kernel (which is a module of the Apache Axis2 project), you will find that no groupId or a version element is defined: (http://svn.apache.org/repos/asf/axis/axis2/java/core/trunk/modules/kernel/pom.xml). Maven reads them from the parent POM file:

<project>
    <modelVersion>4.0.0</modelVersion>

    <parent>
        <groupId>org.apache.axis2</groupId>
        <artifactId>axis2-parent</artifactId>
        <version>1.7.0-SNAPSHOT</version>
        <relativePath>../parent/pom.xml</relativePath>
    </parent>

    <artifactId>axis2-kernel...