You can't use java 7 because of protocol errors

[Goddard]

Java 7 fails when getting the packages from the repo because of outdated protocols.

[disintegrat3]

I had a similar issue, which I solved after digging through stackoverflow (haha, where else!).

1. Create a .mvn directory at the root of the Sharpen directory.
2. Add a "jvm.config" file with the contents "-Dhttps.protocols=TLSv1.2".

After that I was able to build the Sharpen JAR.