Index

• 2017-04-28: Try the JNI but find out JNI is suitable for Java x NativeC co-develope scenario but not suitbale for our case (DLL library built independently). So I explore JNA (Java Native Access) project and found it relevant.

• 2017-05-02: Ping the JNA with Maven Project Structure + Invoke DLL + DLL generated by C++ & G++ Compiler

• 2017-05-02: The original code is using C#, maybe we can try to ping the g++ compile C# as dll possibility?

• 2017-05-02: Now reading the C++ tutorial, some retrofit will be made on the C# code if we stick to C++

• 2017-05-02: The deadline is monday update

• 2017-05-04 Realized that JNA cannot invoke C# dll

• 2017-05-04 Workaround to use Java Runtime.exec() method to call an independent Window Executatble/exe (use csc the c# compiler) throught Java

Guide

C++ Code Compilation Steps:

1. Compile cpp source code: $ g++ -c heyDLL.cpp -Wno-write-strings (the -Wno-write-strings argument is optional)

2. Link stage with DLL generation: $ g++ -shared -o heyDLL.dll heyDLL.o so that the heyDLL.dll can be used by JNA

Build and Run Java Code

1. Build: $(project_home) mvn clean package

2. Invoke: $(project_home) java -cp target/jna-demo_xxx.jar com.myles.demo.App

• note. The DLL should be proven with $ file {dll_name}.dll that its 32/64bit

• note. The DLL must be put at the directory where the JVM runs. If not, change the command to this $(project_home) java -Djna.library.path={path_to_dll_folder} -cp target/jna-demo_xxx.jar com.myles.demo.App

• note. Run the JVM in cygwin-bash, if use git-bash, some system depenedency would be missed.

Reminder

• Cannot use JNA to call C# dll becuase the nature is: JNA -> C/C++ -> C#