JAVA OpenCV Error: Assertion failed (!empty()) in cv::CascadeClassifier::detectM

OpenCV Error: Assertion failed (!empty()) in cv::CascadeClassifier::detectMultiScale, file C:\build\master_winpack-bindings-win64-vc14-static\opencv\modules\objdetect\src\cascadedetect.cpp, line 1681 Exception in thread “Thread-2” CvException [org.opencv.core.CvException: cv::Exception: C:\build\mas