After several days of consideration and research, I’ve decided to change the project license from GNU/GPL V3 (General Public License) to GNU/LGPL V3 (Lesser General Public License). This has been motivated as, being OSGiLiath a set of OSGi bundles that can be executed in any OSGi container, setting a GNU/GPL license could be too restrictive. Moreover, OSGi was created for dynamic binding of several service implementations from many different third-parties at the same time. For example, if OSGiLiath is going to be distributed with the Equinox container, it will be bound with bundles with an EPL License. Or in the case of Apache Fenix, the Apache V2 License is used. This is impossible using the GPL License.
Changing to LGPL gaves me some flexibility: for example, if I would like to distribute my project with the Equinox bundles, I can add a combined license (as the Logback project does). However, the EPL and GNU/GPL licenses are extremely incompatible, as can be read here.
Read also the FSF opinion about that incompatibility.
By the way, Processing is also based in LGPL, so I can distribute with my project without problems 🙂
The GNU/LGPL V3 license can be read here, and it has been updated in the project code (headers and license.txt).