After I opened the jar file released, all the images are not able to display, including the slot items and membership. The game cannot be played completely with the jar version.
The program worked well in the IDE environment, but cannot show images after exported as a jar file. The problem arose because we are not including the images when exporting the jar file. The problem is solved by marking the images folder as resource and we use getClass().getResourceAsStream(image) to get the input stream of image from resources. After configuration, the jar file now works well.