TrueLicense
TrueLicense is a commercial open source engine for license management on the Java Virtual Machine. Due to its functional and modular design TrueLicense scales from simple to complex licensing schemas. TrueLicense features various interfaces for managing free trial periods, subscriptions, multiple editions, internationalization, privacy protection and more.
The source code of this project is covered by the GNU AFFERO GENERAL PUBLIC LICENSE, Version 3. Commercial licensing for use with closed source software is available - see licensing.
For more information, please refer to the documentation at http://truelicense.net/.