I recently learned about IKVM.net which is a Java for Mono (.NET). So I am guessing that there could be out there a implementation of CLR on Java. That can be used to run C# functions in Java, (not really those .NET UI stuff) mainly those codes that are logic or algorithm-oriented programs, one good example would be a “parser” for example.
Something that would not just “convert” the code, something that will execute C# function directly to the JVM allowing it to interact with other Java objects perhaps. As I had this experience trying to use C# to Java converters which the result is most like approximation code which is even harder to fix.
Is there any implementation of CLR on top of JVM at this point in time?
You may be able to use jni4net to bridge between Java and C#.