The Adempiere project is Open Source, and the source code for development versions is freely available. It should be noted that the development sources at times may be not stable or not even compile - if you want stable sources then look at the source code distribution of the latest release. That said, the development versions usually work fine.
The Adempiere sources are managed using the Subversion version control system. Access to the repository is documented in the Hacker's guide
The easiest way to get the sources (and probably the hardest to keep up to date) is to download one of the snapshots from the Adempiere ftp site ( To be setup ).
Read-write SVN access is needed by anyone who needs to able to write to the repository. This includes developers, documentation writers, translators, artists etc. The granting of read-write access is managed by the Commit_Committee