If the last player typed some characters before he pressed enter, which is used to turning to the next player. These characters will be added to next player's input, therefore being affected and may produce incorrect input.
Thanks for your report! The bugs have been fixed by clearing input stream before asking player to press "Enter": Messenger.java: public void waiting() { print("Press ENTER to continue ..."); try { while (System.in.read() != '\n') ; } catch (IOException e) { e.printStackTrace(); } }