From this post (https://forum.videolan.org/viewtopic.php?f=13&t=159873&p=527582&hilit=blu+ray+disc+requires+java#p546583) I note that it includes the libbluray-bdj which I didn't have. So, I installed it: sudo apt install libbluray-bdj Now, when I open the disc, the error no longer appea...