After the release of OpenCV 3.4.2, I have prepared the pre-built version of the Java libraries for OSX, Ubuntu, and Windows 8.1 platforms (64 bits). In this release, there is more extensive support for the Java binding. I also packaged the library as the Processing library – CVImage. Please refer to latest book for details. In addition to the optflow contributed library, it also includes additional contributed libraries, such as bgsegm, face, and tracking.