How to Round up timestamp to number of Days?

PreparedStatement psnmt=con.prepareStatement("SELECT (?)-(?) as DiffDate FROM dual");
psnmt.setTimestamp(1,ctenderdate);
psnmt.setTimestamp(2,btenderdate);
ResultSet resrt=psnmt.executeQuery();
if(!resrt.next())
{
     out.println("No Records Found");
}
else
{
  do
     {
        datediff=resrt.getString("DiffDate");
     }
  while(resrt.next()); 
  System.out.println("the no of days Difference"+datediff);

}

ctenderdate=2015-06-27 00:00:00.0

btenderdate=2015-06-29 00:00:00.0

datediff=1 10:18:51.940000000

Expected datediff=2

How to round it off datediff to number of days