You may be interested that the server should be auto login as Oracle user in case of restart.
1.1. Login as root user and open Login Screen,
Linux: Applications > System Settings > Login Screen
1.2. Provide the information by clicking Automatic Login,
Note: To make sure that Oracle user will be logged in always the Timed Login settings are shown in the screen. These are for DISPLAY SETTINGS as you always need the Oracle user to be logged in.