No, I want to mirror the current state of all engine objects and global variables into a pure, thoughtful object orientated approach in JAVA. This way you can take the benefits of JAVA on a very high abstraction level and all game engine synchronization is done in the background.

Basically, with JNI you can 1.) invoke a JVM from inside a native application (C, C++, etc.) or 2.) run a JVM and invoke from there native code. I think it is possible with a Lite-C stub, a DLL and careful designed packages along with multi-threaded concurrent active classes.