DLL using JNI Java classes

Question

I'm writing a C++ dll (file extension in Visual Studio is .cpp but the code is C) which uses JNI for loading and calling instance methods of some Java classes. As a result my project is made up by C++ source and header files plus some Java class files (the class files for the Java objects used through JNI). I would like to create a single dll library including also the Java class files "in a single bundle". Is it possible to put both the C and Java files into the dll?

Answer 1

This is perfectly possible, though not necessarily intuitive. I haven't tested this but I would imagine it would work easily if you knew what you were doing.

First off, you're going to need a way to package the class file's binary into the native binary you own, and then of course be able to seamlessly read that chunk at any point in time. How you achieve this is up to you, there is no real 'right way' to do it.

That being said, if you can get a handle to the memory where the .class file's data resides (after loading the DLL) and pass it to Java as a byte[] or ByteBuffer , you'd then want to use any one of ClassLoader 's defineClass overloads along with a call to findLoadedClass and then finally loadClass .

This would allow you to load in a class from virtually any data source. As I mentioned before, how you store/retrieve the native data for the class is up to you.