Oracle handles y2k dates with RR instead of YY. Two digit years below 50 are presumed to be 20xx and above 50 are 19xx. Here's the docs and sample from oracle's site:

SELECT TO_CHAR(TO_DATE('27-OCT-98', 'DD-MON-RR') ,'YYYY') "Year"
   FROM DUAL;

Year
----
1998

SELECT TO_CHAR(TO_DATE('27-OCT-17', 'DD-MON-RR') ,'YYYY') "Year"
   FROM DUAL; 

Year
----
2017
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rr date handling and oracle date formatting. HTH