I have seen that I have to import com.googlecode.javacv.cpp.opencv_features2d.BOWImgDescriptorExtractor but it does not find something like this. I have build OpenCV with CMake and I have created the opencv_java249.jar and the libopencv_java249.so file. I have added them to my java project (based on grails, if this matters) and I have not managed to find the BOWImgDescriptorExtractor class. Help, please