Question

I’ve created a c# dll in visual studio 2008

the content of the c# dll is as given below:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace hello
{
    public class Class1
    {
        public static double addUp(double number, double Number)
        {
            return number + Number;
        }
        public static double minus(double number, double Number)
        {
            return number - Number;
        }
    }
}

and through java i’ve loaded the hello.dll using

System.loadLibrary(“hello”);

The java code is as given below:

package pkgnew;
import javax.swing.JOptionPane;
public class check 
{

    public static native double addUp(double number,double Number);
    static 
    {
      try
      {
      System.loadLibrary("hello");
      System.out.println("SUCCESS");
      }catch(Exception ex){ JOptionPane.showMessageDialog(null,"Required DLLs Not Found\n"+ex.getCause(),"Error Loading Libraries", JOptionPane.ERROR_MESSAGE);}
    }

    public static void main(String[] args) 
    {
          new check().getval();
    }

    public void getval() {
        try
        {
       double g=this.addUp(52.2, 51.3);
        }catch(Exception y){System.out.println("ERROR IS:"+y);}
    }
}

but the problem is that i’m getting output as:

OUTPUT

SUCCESS
Exception in thread "main" java.lang.UnsatisfiedLinkError: pkgnew.check.addUp(DD)D
    at pkgnew.check.addUp(Native Method)
    at pkgnew.check.getval(check.java:35)
    at pkgnew.check.main(check.java:29)
Java Result: 1

Can anyone tell me why i’m getting this error….and why i’m not able to call the dll methods

Answer 1

I don’t think you can call native extensions in Java without using JNI wrappers (or at least some library which translates to JNI under the hood). Have you tried out the frameworks/suggestions mentioned in this thread?