[oracle11g] Forgot Oracle username and password, how to retrieve?

Go to SQL command line:- type:

sql>connect / as sysdba;

then type:

sql>desc dba_users;

then type:

sql>select username,password from dba_users;

If sysdba doesn't work then try connecting with username:scott and password: Tiger

You will be able to see all users with passwords. Probably you might find your's. Hope this helps