The Eclipse Public License (EPL) is designed to foster open collaboration and innovation, particularly for software projects, by providing a framework that balances the rights of contributors and users. Understanding how this license handles modifications is crucial for developers who wish to adapt or extend EPL-licensed software.
Under the EPL, you are permitted to modify the original work, whether for personal use or for distribution. When you modify an EPL-licensed project, you create what’s known as a “derivative work.” The license allows you to distribute these derivative works under the terms of the EPL, which means that any modifications you distribute must also be covered by the EPL.
A key aspect of the EPL is its copyleft provision. This requires that any distributed modifications or derivative works must include source code and be licensed under the EPL. This ensures that subsequent users and developers can also access, modify, and distribute the modified code under the same terms. This copyleft mechanism encourages continuous collaboration and sharing within the community, while still allowing developers the flexibility to innovate.
However, the EPL also allows for a certain degree of flexibility when combining EPL-licensed code with other software. If the modifications involve integrating the EPL code with other modules or libraries that are not EPL-licensed, the non-EPL parts do not automatically fall under the EPL. This feature makes the EPL somewhat more permissive compared to other open-source licenses with stricter copyleft terms, such as the GNU General Public License (GPL).
In practical use, the EPL is often chosen for projects that aim to balance openness with a degree of flexibility for commercial use. For example, a company might modify an EPL-licensed library for internal use without needing to distribute the source code of the modifications. However, if the modified software is distributed to others, the EPL’s requirements to share the source code and license it under the EPL come into play.
In summary, the Eclipse Public License allows for substantial freedom to modify and distribute code, with the condition that any distributed modifications or derivative works remain open and accessible under the same licensing terms. This approach supports a collaborative environment where innovation and shared progress are encouraged, while still respecting the original creators’ contributions and intentions.