Initialize Oracle Security (revoke)

Oracle keeping waring you in Enterprise Manager DBControl.

revoke execute on utl_file from public;
revoke execute on utl_http from public;
revoke execute on utl_smtp from public;
revoke execute on utl_tcp from public;
revoke execute on dbms_random from public;

grant execute on utl_tcp to sysman;
grant execute on utl_smtp to sysman;
grant execute on utl_http to sysman;
grant execute on utl_file to sysman;
grant execute on dbms_random to sysman;