If the selected version does not exist or the latest installed version is outdated when 'Use latest version' is selected in the profile, the launcher will download all Minecraft components and Java binary files. If the connection is successful, the launcher will then, depending on profile options, compare the latest version in the latest 'versions' directory to the latest version reported by the server. If a valid 'launcher_profiles.json' file exists but there is no Internet connection, the launcher will offer a 'Play offline' mode if a player was logged in when it was last closed. When logging in, the launcher will first try to verify the login.

If the file does not exist, is corrupt, or no user is logged in, the user must login with a valid premium account, otherwise the user will be directed to play the Demo version or purchase the game. It checks a file called 'launcher_profiles.json' for login credentials. The login screen for launchers without previously logged-in users.Įvery time the launcher is executed, it checks a specific directory where Minecraft stores its files called '.

.jar launcher minecraft