Maven: A Developer's Notebook

Overriding Properties

You have seen that specifying a property on the command line overrides a property defined in project.properties, and you've seen that plug-in properties are superseded by project.properties. Now that you've seen property overrides in action, take a look at how you can use property overriding to customize behavior for a specific project or a specific user.

How do I do that?

In the "Customizing Plug-in Behavior" lab earlier in this chapter, you set the maven.axis.serverside variable in your project.properties file. Try running the axis:wsdl2java goal and setting the maven.axis.serverside property to true:

maven axis:wsdl2java -Dmaven.axis.serverside=true

If you run this, you should see Maven generating a number of different classes and some deployment descriptors for an Apache Axis SOAP service. By setting the maven.axis.serverside property from the command line, you have just overridden the value specified in project.properties. Properties set from the command line take precedence over properties set anywhere else in Maven.

In fact, Maven has a hierarchy of properties files which you can use to customize a build for a specific project or a specific user. Maven reads properties from the following sources, in the order shown:

${basedir}/project.properties

This file is a sibling to both maven.xml and project.xml. This file customizes behavior for a particular project.

${basedir}/build.properties

This file is also a sibling to maven.xml and project.xml, but this file ...