Not directly.

But as JNI is the native interface to Java, and as managed C++ code can call
native code in two ways (using it just works or Platform/Invoke described
here

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vcmxspec/html/v
cmg_part2start.asp )

you could make use of JNI DLLs in a .Net application.

Regards,
Will

I don't see why not.  JNI (or the Java Invocation API) is just a native API.
You should be able to call into the JVM from C++ code compiled with /clr
just as you can call into any other native code.

Likewise, you should be able to implement JNI-callable functions in managed
code by giving them a C++ wrapper that's exported with the proper naming
convention.

-cd