Trying to use DLL from Java (JNA). Unable to load library exception

Question

I have NetBeans project from tutorial which causes exception:

Exception in thread "main" java.lang.UnsatisfiedLinkError: Unable to load library 'simpleDLL': The specified module could not be found.

Tried to put simpleDLL.dll in project libraries, copied file in system32 folder with no success.

Answer 1

I had exactly the same problem with loading a DLL, I solved it in this way:

• As Christian Kuetbach said, check if the simpleDLL you are using is compatible with your processor's architecture, a 32-bit DLL won't work on a 64-bit machine, and also a 64-bit DLL won't work on a 32-bit machine.

• If the DLL is compatible, then the problem may be in your java library path. I put my DLL into the user.dir directory and then I used this code:

  Set Java library path to user.dir or maybe another path you want:

   String myLibraryPath = System.getProperty("user.dir");//or another absolute or relative path
  
   System.setProperty("java.library.path", myLibraryPath);
  

  Load the library:

   System.loadLibrary("libraryWithoutDLLExtension");
  

It worked for me, try it and tell me if it works for you.

Answer 2

Please check if the simpleDLL is 32 or 64 bit. Then check, if the JVM is also 32 or 64 bit. They have to be for the same platform.

You may also specify an absolute path, if you change loadLibrary() to load(): http://www.chilkatsoft.com/p/p_499.asp

Answer 3

I could only run in 32bit (Xp).

Place the DLL in the folder "c:\Windows\System32"

helloWorldDLL lib = (helloWorldDLL) Native.loadLibrary("helloworldDLL", helloWorldDLL.class);

If the error java.lang.UnsatisfiedLinkError: Unable to load library" persists, use Dependency Walker to view the dependent DLLs.

Dependency Walker