What versions of Java, Maven, and protoc are required?

I just tried building ("mvn package" - Windows 7 64bit) from git and it failed. I can't see the exact message because the mvn window closes automatically. It appears to make the \api\target directory, but there are just a couple of subdirectories (no actual files). In addition, it modifies \api\src\main\java\com\bitsofproof\supernode\api\BCSAPIMessage.java by quite a bit.

Any suggestions?