You need to go the other way, calling Java from C/C++ code.
Use JNI again.
In 1.1, JNI provides an interface for calling Java from C, with calls to:
Create a JVM
Load a class
Find and call a method from that class (i.e., main)
This lets you add Java to legacy code. That can be useful for a
variety of purposes, but entails treating Java code as an extension
language (just define or find an interface like
Servlet, and let your
customers subclass from it).
This is not discussed in detail here, but there’s a full code
example in the code archive in directory