Oracle11G password expiration ORA-28002

Problem: The system fails to start, and an error ORA-28002 (oracle password expired) is reported.
Problem formation: After oracle 11G is installed, there will be a default password period (180 days). If the password is not changed within the specified time, the password will expire and the system cannot be used.
Solution:
1. Log in to oracle: sqlplus / as sysdba
2. Change the password expiration to never expire: ALTER PROFILE DEFAULT LIMIT PASSWORD_LIFE_TIME UNLIMITED;
3. Re-change the password (can be the previous password): alter user fpga32 (username) identified by fpga32acconsys (password);

Note: When installing oracle 11G in the future, modify it directly to avoid subsequent troubles;