java.lang.UnsatisfiedLinkError: org.opencv.core.Mat.n_Mat(IIILjava/nio/ByteBuffer;)J

I'm work on project using JavaFX and JavaCV. My main feature in app is based on webcam capture. I'm looking for a way to display frame from OpenCVFrameGrabber into JavaFX component.

I found a way to do it but I get the following error:

Exception in thread "main" java.lang.UnsatisfiedLinkError: org.opencv.core.Mat.n_Mat(IIILjava/nio/ByteBuffer;)J
	at org.opencv.core.Mat.n_Mat(Native Method)
	at org.opencv.core.Mat.<init>(Mat.java:52)
	at org.bytedeco.javacv.OpenCVFrameConverter.convertToOrgOpenCvCoreMat(OpenCVFrameConverter.java:187)
	at org.bytedeco.javacv.OpenCVFrameConverter$ToOrgOpenCvCoreMat.convert(OpenCVFrameConverter.java:61)
	at TestJavaCV$Companion.main(TestJavaCV.kt:20)
	at TestJavaCV.main(TestJavaCV.kt)

I suspect that the application is not working due to not dependency failure. Probably I should provide additional libs for org.opencv.core but I don't know how to achieve this in gradle.

Minimal, Reproducible Example:

build.gradle

dependencies {
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
    testCompile group: 'junit', name: 'junit', version: '4.12'
    compile group: 'org.bytedeco', name: 'javacv-platform', version: '1.5.3'
}

TestJavaCV.kt

import javafx.scene.image.Image
import org.bytedeco.javacv.Frame
import org.bytedeco.javacv.OpenCVFrameConverter
import org.bytedeco.javacv.OpenCVFrameGrabber
import org.opencv.core.Mat
import org.opencv.core.MatOfByte
import org.opencv.imgcodecs.Imgcodecs
import java.io.ByteArrayInputStream

class TestJavaCV {
    companion object {
        private val toOrgOpenCvCoreMat = OpenCVFrameConverter.ToOrgOpenCvCoreMat()

        @JvmStatic
        fun main(args: Array<String>) {
            val grabber: OpenCVFrameGrabber = OpenCVFrameGrabber(0);
            grabber.start()

            val frame: Frame = grabber.grabFrame()
            val mat: Mat = toOrgOpenCvCoreMat.convert(frame)
            val matOfByte: MatOfByte = MatOfByte()

            Imgcodecs.imencode(".png", mat, matOfByte)
            val image = Image(ByteArrayInputStream(matOfByte.toArray()))
        }
    }
}

This question https://stackoverflow.com/questions/42569126/java-lang-unsatisfiedlinkerror-org-opencv-core-mat-n-matiiij answers why you are getting that UnsatisfiedLinkError; the library for OpenCV is not loaded by your Java VM and therefore the relevant native calls cannot be made.

This question https://stackoverflow.com/questions/17767557/how-to-use-opencv-in-using-gradle should help you with configuring OpenCV using Gradle.

Per your comment question "I have a requirement for the application to work on Windows 10, Linux and MacOS." I don't know how to solve that using gradle, however in Java I would inject a different system property per o/s and use that in a static block in your class to load your library:

static {

    String libraryPath = System.getProperty("opencv.path");

    System.load(libraryPath);

}