Sorry for the late reply. We have updated the game so it's now hosted online so you don't need to run it locally :). But from what it looks like, you have something else running on port 8080. Perhaps another game server?
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Sorry for taking this long, was busy making it multiplayer so I can host it online :). Check out my comment above for being able to play it without installing the server.
In case you still want to try to run it locally, your problem was that you are likely using open jdk while we built ours using regular jdk.
Since several people were having trouble we made a couple of changes to it so it supports multiplayer and are now hosting it for some time online for people who want to try it out here: http://220.127.116.11:8080/. The app should also be updated and now just requires the game id that you see in the center top of the web view.