I hit a similar error after installing the node. Seeing that this node hasn't been updated in over 4 years, it may be abandoned. You could try contacting the author but I wouldn't give that much hope.
So maybe there's a easy way to use websockets to access data on node-red from LeapMotion...
Although I don't know java, I have been learning by trial and error on node-red, so it will take me a lot of time to understand that document and create my own solution.... but, maybe someone can help me?
I also have a first generation. I bought one for 30€. I want to control anything... I would like to assign Leap Motion gestures to trigger different flows (swipe to change PowerPoint slide, OBS studio scenes, zoom in and out...a lot of things)
I’ve found that updated leap motion drivers doesn’t use “gestures”, but there’s a live websocket server, so I can access any data, I just don’t know how to make sense of all data. The legacy v2 drivers are supposed to use gestures, but I haven’t got it working. But the objective would be to use leap motion with the current drivers (Orion v4)