During licensing review of Gradle 2.4 in Fedora we found out that it introduces a new dependency, aws-java-sdk, which is non-free.
Most of the code in aws-java-sdk is licensed under Apache License Version 2, just like Gradle, but a few utility classes used for JSON support are non-free. These classes contain a clause that contains usage restrictions (“The Software shall be used for Good, not Evil.”), see the license file and source of class com.amazonaws.util.json.JSONArray.
Such usage restriction makes the license incompatible with The Open Source Definition and The Free Software Definition. Because Gradle binary distribution includes this software, it effectively becomes proprietary software itself.
I think this is a serious issue and should be fixed ASAP.