Re: Loading a 3rd party from a java code

From:

=?ISO-8859-1?Q?Arne_Vajh=F8j?= <arne@vajhoej.dk>

Newsgroups:

comp.lang.java.programmer

Date:

Tue, 15 Feb 2011 20:54:53 -0500

Message-ID:

<4d5b2e64$0$23751$14726298@news.sunsite.dk>

On 15-02-2011 18:35, Ian Shef wrote:

Arne Vajh?j<arne@vajhoej.dk> wrote in news:4d580572$0$23756$14726298
@news.sunsite.dk:

On 13-02-2011 03:42, dvir shaty wrote:

   I am trying to load a function from a 3rd party DLL from my java code
(in eclipse).

   Can you please tell me how to do it?

   I tried to use the following:

------------------------------------------------
package tal.packege;
class talclient
{
      static
      {
          System.loadLibrary("talclient");
      }
      public static void main(String ar[])
      {
          System.out.println("Hello world from Java");
          talclient t=new talclient();
               String s = "172.16.10.31";
           int a = 8888;
           int b = 0;
          t.tal_connect(s,a,b);

      }
      public native void tal_connect(String s, int a, int b);
}

------------------------------------------------

I get the following exception:

Exception in thread "main" java.lang.UnsatisfiedLinkError:
tal.packege.talclient.vtc_connect(Ljava/lang/String;II)V
      at tal.packege.talclient.vtc_connect(Native Method)
      at tal.packege.talclient.main(talclient.java:16)

According to the dll help file the arguments are defined as:

int tal_connect( char *servername,
           Int portnum,
           Int options)

The dll is stored in c:\windows\system32.

JNI does not support calling arbitrary functions in a
DLL.

You need to create wrapper function and DLL that is
JNI compatible and call that.

And furthermore...
- Your code calls tal_connect, but the error message is for vtc_connect.
- char * is NOT the same as java.lang.String

Both will somewhat become obvious when creating the
JNI wrapper.

The output from javah will show a lot.

Arne