How to make Swingbench 2.6 and Oracle 18c work together?
Partially it could be fixed by adding 

alter session set "_ORACLE_SCRIPT"=true;


command at the top of these five files:

swingbench/sql/CreUser.sql
swingbench/sql/json_createuser.sql
swingbench/sql/shdg_createuser.sql
swingbench/sql/soedgcreateuser.sql
swingbench/sql/tpcds_createuser.sql



During configuration sys as sysdba Administrator Username is filled by default. And during oewizard script execution Java throw a lot of 



  ORA-01950: no privileges on tablespace 'USERS'


exceptions. So I've resolved it by:

$ sqlplus / as sysdba
SQL&gt; grant unlimited tablespace to sys;
SQL&gt; alter user sys quota unlimited on users;