where opencv_core is a class and Mat is a static nested class,
org.bytedeco.javacpp.opencv_core::Mat # returns class, as expected
# org.bytedeco.javacpp.opencv_core$Mat # not valid expression, as expected
java_import 'org.bytedeco.javacpp.opencv_core$Mat' # works as expected
java_import 'org.bytedeco.javacpp.opencv_core::Mat' # NameError: cannot load Java class org.bytedeco.javacpp.opencv_core::Mat
3:07:15 PM byteit101: I think using :: makes sense and . does not but the string form probably does not split on :: which is a bug