Maven can be used locally in order to compile, test, build the jar file and install it within local repository (userHome/.m2/repository). You just need to go to the directory where you cloned the application and type:
mvn clean package
How to run the application
Once the application is packaged, it is necessary to go to /app_path.../target/ and type:
java -Dsun.java2d.xrender=f -Xmx256m -Xms128m -jar wallpaperdownloader.jar
This jar will contain all the libraries needed for running the application successfully.
The first the application runs, a new directory is created at /userHome/.wallpaperdownloader. This directory contains this stuff:
A log file called wallpaperdownloader.log where you can see all the information generated by the application.
A file called config.txt where all the application settings are saved.
A directory called downloads where you'll find all the wallpapers downloaded by the application.
It is possible to open the download directory directly using the application via Miscelanea tab clicking Open button.