Set defautt Timestamp to an attribute ADF

import java.sql.Timestamp;

         setCreationDate(new Timestamp(System.currentTimeMillis()));
         setLastUpdateDate(new Timestamp( System.currentTimeMillis()));

If you want to set the time in  EO attribute, use the expression adf.CurrentDateTime (for timestamp) or adf.CurrentDate (for date)

http://abakalidis.blogspot.com/2007/02/oracle-adf-accessing-current-date-and.html
http://adfgouravtkiet.blogspot.com/2012/11/how-to-set-default-values-for-entity.html