Using some of the JavaCV classes may lead to exception:

java.lang.RuntimeException: No native JavaCPP library in memory. (Has Loader.load() been called?)

Looks that JavaCV does not load JavaCPP libraries on its own. If something loads them first, there is no issue.

Simple code to reproduce the exception:

import org.bytedeco.javacv.Frame;

public class NoNativeJavaCPPBug {
    public static void main(String[] args) {
//        String s = org.bytedeco.opencv.global.opencv_core.CV_VERSION;
        Frame frame = new Frame(320, 200, 8, 1);
    }
}

If you uncomment the line with CV_VERSION there is no exception, as OpenCV wrapper will load JavaCPP libraries.