Ok sorry i haven't see, your /etc/hosts doesn't have the hostname you are trying to resolve.
So in the hosts file on OracleVM1-h you need to add this :
192.168.12.3 OracleVM2-h
And in the hosts file on OracleVM2-h you need to add :
192.168.12.2 OracleVM1-h
Then restart your network services.
Regards,
Julien.