java.lang.UnsatisfiedLinkError - JNI

Question

I keep getting a java.lang.UnsatisfiedLinkError error every time I run my program. I have a native, a wrapper, and the program to call the native through the wrapper.<

Answer 1

I think the problem is that your JNI signature doesn't match. That is:

JNIEXPORT void JNICALL native_MessageBox(string text, string title);

should be something like:

JNIEXPORT void JNICALL java_com_example_Wrapper_native_MessageBox(string text, string title);

where, java_com_example should be replaced with your package name (. to be replace with _ in package name).

OR

I would suggest you to generate your native function signature and declaration using javah -jni option available in java.

Answer 2

If you test with

nativeFile = new File(filename + ".dll");
    if (!nativeFile.exists())
        System.exit(1);

you should use it !!

System.load(nativeFile);

There are two different ways to load a native library into a running Java program:

• System.loadLibrary(String) and System.load(String).

• The System.loadLibrary method allows us to load a library from the "default" path.

  System.loadLibrary("HelloWorld");

• System.load allows us to load a library from anywhere via its absolute path.
  System.load("c:/path/to/dll/HelloWorld.dll");

Answer 3

Another thing which could be reason for that error is missing header file when you compile our cpp library. Make sure that you included header in your cpp file.