How to UnLock "xelsysadm" User

If you have another user with administrator rights, use it to unlock xelsysadm.
If not, then use sqldeveloper to browse the usr table and change the columns "usr_login_attempts_ctr" and "usr_locked" to 0 for xelsysadm user.

update usr set usr_login_attempts_ctr=0 where usr_login='XELSYSADM';
update usr set usr_locked=0 where usr_login='XELSYSADM';
commit;