How to blend two images using OpenCV Java?

import org.opencv.core.Core;
import org.opencv.core.Mat;
import org.opencv.highgui.HighGui;
import org.opencv.imgcodecs.Imgcodecs;
public class AddingTwoImages {
   public static void main( String[] args ) {
      //Loading the OpenCV core library
      System.loadLibrary( Core.NATIVE_LIBRARY_NAME );
      //Reading the input images
      Mat src1 = Imgcodecs.imread("D://images//a1.jpg");
      Mat src2 = Imgcodecs.imread("D://images//a2.jpg");
      //Creating an empty matrix to store the result
      Mat dst = new Mat();
      //Adding two images
      Core.addWeighted(src1, 0.4, src2, 0.8, 0, dst);
      HighGui.imshow("Adding two images", dst);
      HighGui.waitKey(0);
   }
}<strong> </strong>