Java Errors

Exception in thread "main" java.lang.Exception: unknown exception at org.opencv.videoio.VideoCapture.VideoCapture_2(Native Method) at org.opencv.videoio.VideoCapture.<init>(VideoCapture.java:54) at cam.Webcam.main(Webcam.java:16) TRY this code after VideoCapture VideoCapture camera = new VideoCapture();     try { Thread.sleep(4000); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); }

 Highgui.imwrite("camera.jpg", frame); doesn't work any more use Imgcodecs.imwrite instead

OpenCV Error: Assertion failed (!empty()) in cv::CascadeClassifier::detectMultiScale, file C:\builds\master_PackSlaveAddon-win32-vc12-static\opencv\modules\objdetect\src\cascadedetect.cpp, line 1634 Exception in thread "main" CvException [org.opencv.core.CvException: cv::Exception: C:\builds\master_PackSlaveAddon-win32-vc12-static\opencv\modules\objdetect\src\cascadedetect.cpp:1634: error: (-215) !empty() in function cv::CascadeClassifier::detectMultiScale ] at org.opencv.objdetect.CascadeClassifier.detectMultiScale_1(Native Method) at org.opencv.objdetect.CascadeClassifier.detectMultiScale(CascadeClassifier.java:103) solution : make sure that you do this following steps : - path absolute - test if empty  CascadeClassifier faceDetector = new CascadeClassifier("C:/opencv/sources/data/haarcascades/haarcascade_frontalface_alt.xml");               Mat image = Imgcodecs.imread("D:/network/opencv/lena2.png");           if (faceDetector.empty(

Running FaceDetector Exception in thread "main" java.lang.NullPointerException at cam.FaceDetector.main(FaceDetector.java:20) solution the path absolute solution : make sure that you do this following steps : - path absolute - test if empty  CascadeClassifier faceDetector = new CascadeClassifier("C:/opencv/sources/data/haarcascades/haarcascade_frontalface_alt.xml");               Mat image = Imgcodecs.imread("D:/network/opencv/lena2.png");         if (faceDetector.empty()){      System.out.println("faceless");     }     if(image.empty()){      System.out.println("imageless");     }