IKVMClass is an OpenJDK fork built for IKVM.NET. Contains some work from Jeroen Frijters, Windward Studios, and ikvm-revived as well.
You need to add this ikvmstub file to your boot class path for the build, cd into /OpenJDK and javac -g:none -sourcepath sourcepath282 -bootclasspath ikvmstubs.jar!