Oracle JRE7 and JRE6 only supports headful java on an ARMv7 architecture. The Raspberry Pi is an ARMv6 system, so only headless java is supported.
THe system is not a power house, but once the system boots and is running, it is capable of being used as a intermediate OPC UA server. Ill post back with more soon, just trying to find time to do up a write-up of how to install Ignition on a RPi. I had this working an hour after I got mine…