C#呼び出しcダイナミックライブラリ、Java呼び出しcダイナミックライブラリ

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Runtime.InteropServices;

namespace TestDll
{
    class Program
    {
        [DllImport("user32.dll", EntryPoint = "MessageBoxA")]
        static extern int MsgBox(int hWnd, string msg, string caption, int type);

        static void Main(string[] args)
        {
            Program.MsgBox(0, "  ", "Test", 0x30);
        }
    }
}

public class HelloWorld {
	public interface CLibrary extends Library {  
        CLibrary INSTANCE = (CLibrary)Native.loadLibrary("user32.dll", CLibrary.class);  
        int MessageBoxA(int hWnd, byte[] msg, byte[] caption, int type);
    }  
	
	int MessageBox(int hWnd, String msg, String caption, int type)
	{
		byte[] gbkMsg = null;
		byte[] gbkCaption = null;
		try {
			gbkMsg = msg.getBytes("GBK");
			gbkCaption = caption.getBytes("GBK");
		} catch (UnsupportedEncodingException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return CLibrary.INSTANCE.MessageBoxA(hWnd, gbkMsg, gbkCaption, type);
	}
  
    public static void main(String[] args) {  
    	HelloWorld hel = new HelloWorld();
		hel.MessageBox(0, "  ", "Test", 0x30);
    }  
}

JNAライブラリのダウンロードアドレス:
JNAパッケージ:
https://maven.java.net/content/repositories/releases/net/java/dev/jna/jna/4.0.0/jna-4.0.0.jar
https://maven.java.net/content/repositories/releases/net/java/dev/jna/jna-platform/4.0.0/jna-platform-4.0.0.jar