Unknown exception while using background subtractor

Question

Im trying to implement BackgroundSubtractorMOG2 in opencv java. Im getting this exception from the apply method. Code:

    package com.java.opencv;

import org.opencv.core.Core;
import org.opencv.core.Mat;
import org.opencv.video.BackgroundSubtractor;
import org.opencv.video.BackgroundSubtractorMOG2;
import org.opencv.video.Video;
import org.opencv.videoio.VideoCapture;

import com.atul.JavaOpenCV.Imshow;

public class HelloCV extends BackgroundSubtractorMOG2{
    protected HelloCV(long addr) {
        super(addr);
        // TODO Auto-generated constructor stub
    }

    static{ System.loadLibrary(Core.NATIVE_LIBRARY_NAME); }
    public static void main(String[] args){
        VideoCapture capture = new VideoCapture(2);
        HelloCV helloCV = new HelloCV(0);
          Mat camImage = new Mat();
          BackgroundSubtractorMOG2 mog2 = Video.createBackgroundSubtractorMOG2(10, 16, true);
            if (capture.isOpened()) {
                while (true) {
                    capture.read(camImage);


                    Mat fgMask=new Mat();
   /*Line:30*/      mog2.apply(camImage, fgMask,0.1);

                    Mat output=new Mat();
                    camImage.copyTo(output,fgMask);
                    Imshow im = new Imshow("Title");
                    im.showImage(output);
                   // displayImageOnScreen(output);
                   }
                }
    }

}

Exception in thread "main" java.lang.Exception: unknown exception at org.opencv.video.BackgroundSubtractor.apply_0(Native Method) at org.opencv.video.BackgroundSubtractor.apply(BackgroundSubtractor.java:25) at com.java.opencv.HelloCV.main(HelloCV.java:30)