This repository contains three separate examples of calling a simple C++ library from Java code.
The example library doesn't do anything but contains a class, MyClass, forcing us to support C++ (and not just plain C).
CMake is used to build this, since locating the dependencies got outside the range of my make-fu. The project is supposed to be portable to all major platforms.
Three different wrappers are used, documented below. Each one achieves the same goal, which is using this C++ class from Java code.
This needs the SWIG tool: http://www.swig.org/
SWIG parses the C++ header file and generates both the C++ JNI code and the Java native and helper classes.
JNA allows Java code to use C dynamic libraries directly. Because our library is in fact C++, a small wrapper is included that wraps it as C code.
You will need the JNA jar to run this: https://github.com/java-native-access/jna
This examples uses JNI directly, without auto-generation. The MyClass class in Java code just declares its methods as being "native", they are provided by the dynamic library.