View user roles in Oracle

To view available system privileges, query DBA_SYS_PRIV.

SQL> select * from DBA_SYS_PRIVS;

To view available roles, query DBA_ROLES.

SQL> select * from DBA_ROLES;

To view roles assignated to a user, query DBA_ROLE_PRIVS.

SQL> select * from DBA_ROLE_PRIVS where grantee = 'BEN';