Question

call .dll from java code

Asked by: JagdishDevaku

Hi All,
       I am very new to the concept of JNI, is it possible to call .net .ddl from java code?? Please let know me know the process.

Thanks in advance.

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Asked On
2009-10-15 at 02:34:00ID24814216
Tags

JNI call .dll from java code

Topics

Java Native Interface (JNI)

,

Java Programming Language

,

Java Standard Edition

Participating Experts
5
Points
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Comments
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Answers

 

by: ksivananthPosted on 2009-10-15 at 02:38:19ID: 25578788

as long as you write a JNI Wrapper, you would be able to call the function

 

by: ksivananthPosted on 2009-10-15 at 02:40:01ID: 25578799

 

by: alb66Posted on 2009-10-15 at 02:40:30ID: 25578802

Look at:

"Espresso- Java & .NET Native Interoperability - Part I" at
http://www.codeproject.com/KB/dotnet/Espresso.aspx

 

by: CEHJPosted on 2009-10-15 at 04:22:47ID: 25579334

JNA makes this a lot easier:

https://jna.dev.java.net/

 

by: JagdishDevakuPosted on 2009-10-15 at 06:11:32ID: 25580105

Hi,

      This article talking about accessing java from .net, but i need in reverse process.

 

by: abhishek88Posted on 2009-10-31 at 11:50:32ID: 25710993

Hi

You can use Java Native Interface to call the dll from Java

http://java.sun.com/j2se/1.4.2/docs/guide/jni/spec/jniTOC.html

Just look at the above mentioned link and use native loaders like
System.loadLibrary
System.load
to load DLL files from java




 

by: JagdishDevakuPosted on 2009-11-05 at 00:42:40ID: 25747634

Actually this solution talking about c,c++, but iam looking for .dll with out using any third party tool. Please let me know any thing as such.

Thanks in advance


 

by: klymptzicPosted on 2009-11-05 at 00:45:14ID: 25747642

Did you try System.load(...) / System.loadLibrary(...)

 

by: JagdishDevakuPosted on 2009-11-05 at 01:14:19ID: 25747772

i tried with both methods.

 

by: klymptzicPosted on 2009-11-05 at 02:09:33ID: 25748013

Any exception you see during the invocation?

 

by: JagdishDevakuPosted on 2009-11-05 at 02:46:38ID: 25748198


My Code is :

        public class JNIFoo {    
   public native String nativeFoo();    

   static {
       System.loadLibrary("C:\\WINDOWS\\system32\\alrsvc.dll");
       //System.load("C:\\WINDOWS\\system32\\alrsvc.dll");
   }        

   public void print () {
   String str = nativeFoo();
   System.out.println(str);
   }
   
   public static void main(String[] args) {
   (new JNIFoo()).print();
   return;
   }
}


Error Message:



Exception in thread "main" java.lang.UnsatisfiedLinkError: JNIFoo.nativeFoo()Ljava/lang/String;
   at JNIFoo.nativeFoo(Native Method)
   at JNIFoo.print(JNIFoo.java:9)
   at JNIFoo.main(JNIFoo.java:14)


 

by: CEHJPosted on 2009-11-05 at 03:35:38ID: 25748434

You can't load system dlls directly in JNI. You need to load them via a custom JNI dll. That's one of the reasons i suggested you use JNA

 

by: klymptzicPosted on 2009-11-05 at 03:55:13ID: 25748539

If the function within the .DLL that need to call belongs to an object , then your Java program will not work.

Easiest is wrap the DLL in a plain-old-DLL written in C++ which can be loaded and called from Java.  

 

by: JagdishDevakuPosted on 2009-11-05 at 23:19:26ID: 31641529

this information i found while googling.

 

by: CEHJPosted on 2009-11-06 at 00:57:20ID: 25757628

JagdishDevaku, i'm wondering why you accepted that answer where the part that's correct (the first sentence is incorrect) repeats what i'd already said?

20120131-EE-VQP-002

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