You cant use the repositories to install ignition on the RPi, you have to install manually from tar.gz. I recommend untarring them to /opt/ignition.
As for my write up, I’ve been absolutely swamped lately, so I have not had time. I am still going to get it done this month.
As previously stated, the RPi has an ARMv6 architecture, so it cant run headful using the Oracle binaries (so no client, only server). I have not tried openjdk, but I presume they would be the same. To get headful java from Oracle, you need an ARMv7 architecture. I have a few of the following boards on order.
http://www.hardkernel.com/renewal_2011/products/prdt_info.php?g_code=G133999328931
Im hoping to get debian/ubuntu running on them, as those operating systems support ARMv7 architectures.