Thanks Rob,FYI: In exploring B4J capabilities, did seek for building this functionality with B4J instead of Java.
See (http://www.rwblinn.de/b4j/b4jhowto/examples/b4jhowtojavaobject.zip) which is one of my B4J HOWTOs example projects.
Select net.NetNetworkInterface from the accordion.
@tstewardI am researching/working on a new version that should work for mac.
mac = File.ReadString("/sys/class/net/eth0","address")