在 java.library.path 中找不到库

Question

I'm a newbie to JNI, so I was trying this introduction to JNI tutorial earlier that just calls native to print Hello World! Everything went fine until the point that I wanted to run the java file, at which I keep getting the error: Exception in thread "main": java.lang.UnsatisfiedLinkError: no hello library found in java.library.path. I have googled the error and looked at a lot of peoples' suggestions, but none worked for me unfortunately! I have tried the following:

• Running with command: java -Djava.library.path = " Path to library " HelloWorld
• setting the LD_LIBRARY_PATH to my .so path

Everyone else had their issues resolved after doing one of the two above, but not me!

Here is the Java Code:

public class HelloWorld {

    static {
        System.loadLibrary("hello");
    }

    private native void printHelloWorld();

    public static void main(String[] args) {
        new HelloWorld().printHelloWorld();
    }
} 

And code for native is as follows:

void JNICALL Java_printHelloWorld(JNIEnv *env, jobject obj) {
    printf("HelloWorld!");
}

EDIT: I even tried copying the library to the actually directory of java.library.path, but it's still giving me the same error!

Answer 1

What is your library called? If your paths are correct, your library name is probably wrong. On Windows the file needs to be called hello.dll , OS X (Java < 1.7) libhello.jnilib , OS X (Java >= 1.7) libhello.dylib and just about everything else will be libhello.so . Notice that the Windows dll file is the only file name without the "lib" prefix and that the "lib" prefix is not used when calling System.loadLibrary("hello") . If you are still experiencing a problem loading the lib, try System.load("/path/to/my/libhello.so") to try and load the library directly.

Answer 2

@Alex Barker The version

System.load("/path/to/my/libhello.so")

does not resolve dependencies. If there are dependencies upon other user-defined libraries, they need to be loaded before.