Invoking methods in C++ from Java

Question

I'm invoking the Java Virtual Machine from my C++ program like is described here: http://java.sun.com/docs/books/tutorial/native1.1/invoking/invo.html
So, I run my C++ program (let's call it C), C invokes the JVM and starts a Java program (let's call it J). C can now invoke methods in J. Now I want J to invoke a method in C. Is this possible?

Answer 1

Yes it is.
However your C code that you want to invoke from java must be defined as "native" - that is, it is defined as the implementation for java methods that are declared native.
The possibly most confusing part is where to put the C code and how to make the java-C linkage.
o You can put the C code in a DLL, and use a "loadLibrary" call to make it available.
o Alternatively, and perhaps more likely, your original C/C++program can make "registerNative" calls to the JVM to identify to it the native implementations.