java的文件加密程序，只是改变了一下文件的头信息，让程序无法打开。解密再改回来。玩玩可以。-java file encryption program, but only changed a bit file header information, so that program can not open. Decrypted and then change it back. Can play.

Java Connect Four game. With Gui and "human vs human" and "human vs computer" play modes