(Java Chinese Chess v2.1 This version mainly modifies the bugs and part of the code framework in the previous version ① adds network combat and human-computer combat modes ② adds repentance and surrender functions ③ adds system tray functions ④ adds chat windows ⑤ adds game status prompt functions ⑥ adds timers ⑦ In view of the new features of JDK1.7 used in the previous version, many people cannot run directly, So this version removes the new features of JDK1.7 ⑧ modifies the bugs in the previous version, etc. This data includes the following attachments:)