Java creator James Gosling called Microsoft's decision to support C and C++ in the CLR the "biggest and most offensive mistakes that they could have made".
Scary stuff? Not really. Just some FUD:
Low-level language + JNI + Java = Doh!
Update... Ignore my feeble effort to dispell Gosling's FUD. Don Box already has this covered: "Huge Security Hole in Solaris and JVM"