[FIXED] System.loadLibrary() error -- unable to specify a relative or absolute path

Issue

I have an issue with specifying the path to the x64 OpenCV DLL.

I was using

static{
    System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
}

to load the OpenCV x64 DLL and it worked fine in NetBeans (using -Djava.library.path=".\opencv\x64" but not with a .jar outside of the IDE.

Running the built .jar (with or without -Djava.library.path=".\opencv\x64") throws:

Exception in thread "main" java.lang.UnsatisfiedLinkError: no 
    opencv_java330 in java.library.path

There are countless questions and solutions regarding this issue here.

But, they all require a relative path to the folder containing the DLL -- I cannot specify either an absolute or a relative path to the folder where the x64 OpenCV DLL is located.

System.loadLibrary("%UserProfile%/Documents/NetBeansProjects/ProjectName/opencv/x64/");

throws an

java.lang.UnsatisfiedLinkError: no %UserProfile%/Documents/NetBeansProjects/ProjectName/opencv/x64/ in java.library.path error.

Direct path to the folder throws the same error.

Just System.loadLibrary("/opencv/x64/"); (with or without the leading dot) also throws the same error.

Any help with this issue would be greatly appreciated.

Solution

Probably you have a wrong order of the parameters. Find below a working example.

Assuming the following structure.

bin\
dist\
opencv\x64\opencv_java320.dll
src\foo\Test.java

Test.java

package foo;
class Test {
    public static void main(String[] args) {
        // note: the parameter is the library name, no extension, no path
        System.loadLibrary("opencv_java320");
        System.out.println("library loaded");
    }
}

class path on file system

• compile

  javac -d bin/ src/foo/Test.java
  

• run

  java -cp bin -Djava.library.path=opencv/x64 foo.Test
  

• output

  library loaded
  

class inside a JAR file

• create executeable JAR file

  echo Main-Class: foo.Test > manifest.mf
  jar cfm dist/application.jar manifest.mf -C bin/ .
  

• execute the JAR file with relative path

  java -Djava.library.path=opencv/x64 -jar dist/application.jar
  

• execute the JAR file in the current directory

  cd dist
  java -Djava.library.path=../opencv/x64 -jar application.jar
  

• output for both JAR executions

  library loaded
  

Answered By - SubOptimal