iDempiere source code is hosted at GitHub using a git repository
The built iDempiere source is licensed under the GNU General Public License version 2 (or later), can be browsed online or checked out locally with Git:
If you’d like to learn more about the code and best practices to contribute to the iDempiere project, we have guides for contributing to iDempiere.
You can download/clone the sources from https://github.com/idempiere/idempiere