There are six types of properties that you can use within a Maven application POM file:
Built-in properties
Project properties
Local settings
Environmental variables
Java system properties
Custom properties
It is always recommended that you use properties instead of hardcoding values in application POM files. Let's see a few examples.
Let's consider the example of the application POM file inside the Apache Axis2 distribution module, which is available at http://svn.apache.org/repos/asf/axis/axis2/java/core/trunk/modules/distribution/pom.xml. This defines all the artifacts created in the Axis2 project that need to be included in the final distribution. All the artifacts share the same groupId element as well as the version elements of the distribution module. This is a common scenario in most of the multimodule Maven projects. Most of the modules (if not all) share the same groupId and the version elements:
<dependencies>
<dependency>
<groupId>org.apache.axis2...