Start with Oracle Database 12c says, Oracle said goodbye Database Console which came with Oracle 10gR1 Version

10g was used OC4J and 11g was used weblogic. Also We were using emctl/emca commands to manage those systems.

12c brings a new tool called Database Express.

The DB Express runs entirely with pl/sql code within the XDB schema. It’s XDB that leverages its features to enable a web-based console, and it’s embedded by default in the database.

To enable it,

1.It’s necessary to check that the parameter dispatchers is enabled for XDB:

SQL> show parameter dispatchers

NAME TYPE VALUE
----------- ------ -----------------------------------
dispatchers string (PROTOCOL=TCP) (SERVICE=ORACLEXDB)

2.Execute the DBMS_XDB.setHTTPSPort procedure to set the HTTPS port 5503 or run the DBMS_XDB.setHTTPPort procedure to set the HTTP port 5509 for EM Express

In this case I will use HTTPS config.

SQL> exec dbms_xdb_config.sethttpsport (5503); ---> You can prefer one other ports

PL/SQL procedure successfully completed.
3. If you want to check port number you can use below query

SQL> select dbms_xdb_config.gethttpsport () from dual;

DBMS_XDB_CONFIG.GETHTTPSPORT()
------------------------------
5503

4. Login to Database EM Express Home Page.

https://<IP:Hostname>:YOUR_PORT/em