MPXJ is developed using Eclipse, with an ant build script to automate various build and deployment tasks. MPXJ does however use Maven to generate its web site and generate artifacts which are uploaded to a public Maven repository. It does this by creating a version of the project using the skeleton Maven directory structure found in the maven directory of the distribution.
In order to populate this skeleton structure, execute the following ant target:
Once you've done this, you should end up with a working Maven project in the maven subdirectory.