d2j is a library that parses Android dex bytecode and transform it in Soot internal jimple representation. Soot is a bytecode analysis framework developed by McGill University (http://www.sable.mcgill.ca/soot/).
This is a regular maven project. Soot libraries are fetched from conjars.org. You can also upload them to your local repository if you prefer to recompile them yourself.
You must populate the directories in src/test/cases with either apk files or directly dex files (for example compiled with smali). An android.jar stub is provided.