If you can log in to any of the users, you can use the method to know which users are currently available.
SELECT distinct owner from All_objects to view the current user.
If you don't set a password when you install it,
Oracle has three default user names and Passwords
1. User name: sys password: change_on_install
2. User name: System Password: Manager
3. User name: Scott Password: Tiger
Or maybe you set a password that complies with the Oracle check rule when you install it, but the password is incorrect when you log in, which may be the reason for the character set you installed at the time of installation.
Solution:
1. You can change other account password after login using SYSDBA account
Run cmd as follows input command Sqlplus/as sysdba ---------with sys login Super User (SYSDBA)
2. Unlock your account
Alter user username account unlock; ---------unlocked (must be with ";" No.
Take the system user name as an example, the command is the alter user SYSTEM account unlock;
3. Set a new password for the account
Alter user username identified by password; -------------Change Password (password plus no double quotation marks can be, must be with ";" No.
Take the user Name System password Dhee as an example, that is, the command is alter user system identified by Dhee;
Then log in with your changed password.
Pending update ...
About Oracle Default user Name System password incorrect login not on solution