GPL Compatibility
The Apache Software Foundation and the Free Software Foundation agree that the Apache License 2.0 is a free software license, compatible with version 3 of the GNU General Public License (GPL). Compatibility in this case means that since the rights granted by the Apache License 2.0 are a subset of those of the GPL version 3, a project combining GPL version 3 and Apache License 2.0 code needs to be licensed under the GPL version 3.
In addition, the Free Software Foundation considers all versions of the Apache License (as of 2007) to be incompatible with the previous GPL versions 1 and 2.
Read more about this topic: Apache License