As I've mentioned before, once the user inputs their information, the application would then store/write that information to a file so we could have access to it at any time. Then the next step is reading and writing back those very pieces of information to a hashMap, designed to store the username(key) and it's password(value), so once a user wants to sign in, we could easily approve its username and password. In another word, it would be easy to apply the proper exceptions to it. Also when signing up, I've coded some regex to make sure the entered values are correct and as the standards.