Face preprocessing is not working in java. [closed]

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I am working on face recognition using java library of open cv. I got stuck on face pre processsing phase. here is my code.

    double desiredFaceHeight=70;
    double desiredFaceWidth=70;
    double desiredLen=(DESIRED_RIGHT_EYE_X-0.16);
    try{
    double dy= (face.getRightEye().y-face.getLeftEye().y);
    double dx= (face.getRightEye().x-face.getLeftEye().x);
    double len=Math.sqrt((dx*dx)+(dy*dy));
    double scale=desiredLen*desiredFaceWidth/len;
    // Get the transformation matrix for the desired angle & size.
    Mat rotMat=Imgproc.getRotationMatrix2D(face.getCenterOfEyes(),face.getEyesAngle(), scale);

    //Shift the center of the eyes to be the desired center.
    double ex= desiredFaceWidth*0.5f-face.getCenterOfEyes().x;
    double ey=desiredFaceHeight*DESIRED_LEFT_EYE_Y-face.getCenterOfEyes().y;
    rotMat.put(0,2,rotMat.get(0,2)[0]+ex);//view
    rotMat.put(1,2,rotMat.get(1,2)[0]+ey);//view

    Mat warped = new Mat((int)desiredFaceHeight, (int)desiredFaceWidth,CvType.CV_8U,new Scalar(128));
    //Mat warped=face.getFace();
    Imgproc.warpAffine(face.getFace(),warped, rotMat, warped.size());

but it does not gives transformed face. please describe what's wrong I am doing.