Connect to Oracle RAC Database server

Oracle RAC database uses service-name instead of service-id. Hence, you would need a connection string formatted for using service-name.

Lets say your non-RAC server was hosted on "abc.xyz.com" @ port 1521 and your SID is oradb01, then your connection string would have been :

  jdbc:oracle:thin:@abc.xyz.com:1521:oradb01

On a oracle RAC database server with service-name as oradb01, your connection string would be :

 jdbc:oracle:thin:@//abc.xyz.com:1521/oradb01

Note : I assume you are using Oracle thin driver for Java.

Oracle Convert CSV to ROW

Allow Only Numeric values in the CSV : 
WITH parameter_csv AS (select :1 as val from dual)
SELECT  REGEXP_REPLACE(REGEXP_SUBSTR( val, '[^,]+', 1, LEVEL ),'[^0-9]','')  AS id
           FROM    parameter_csv
           CONNECT BY LEVEL <=
                LENGTH( REGEXP_REPLACE(val, '[^,]+', '' ) ) + 1

If you can afford it not to be parametrized (no ? marks in SQL) Needs Oracle 11g:
select * from xmltable('"this","is","my","csv"');
or 
select * from xmltable('1,2,3,4');