When searching for non-primary key in MySQL using DAO it keeps returning a null object

Question

The first method works but the second method keeps returning a null object. I don't see any difference except that flight_no is the primary key. What went wrong and what's the rationale here?

public Flight getFlight(String flight_no) {
Flight flight=null;
try {
    Connection con = getConnection();
    PreparedStatement ps = con.prepareStatement("Select * from 
    flightInformation where flight_no=?");
    ps.setString(1, flight_no);
    ResultSet rs = ps.executeQuery();
if(rs.next()) {
    flight = new Flight();
    flight.setFlight_no(rs.getString("flight_no"));
    flight.setDeparture_date(rs.getString("departure_date"));
    flight.setDeparture(rs.getString("departure"));
    flight.setPrice(rs.getInt("price"));
}
    con.close();
}
catch(Exception e){
    e.printStackTrace();
}
return flight;
}


public Flight getFlight2(String departure_date, String departure) {
Flight flight=null;
try {
    Connection con = getConnection();
    PreparedStatement ps = con.prepareStatement("Select * from 
    flightInformation where departure_date=? and departure=?");
    ps.setString(1, departure_date);
    ps.setString(2, departure);
    ResultSet rs = ps.executeQuery();
if(rs.next()) {
    flight = new Flight();
    flight.setFlight_no(rs.getString("flight_no"));
    flight.setDeparture_date(rs.getString("departure_date"));
    flight.setDeparture(rs.getString("departure"));
    flight.setPrice(rs.getInt("price"));
}
con.close();
}
catch(Exception e){
    e.printStackTrace();
}
return flight;
}

To keep things simple I only use varchar and integer in MySQL:

create table flightinformation (flight_no varchar(6) primary 
key, departure_date varchar(10), departure varchar(20), price 
int);

And the bean which is nothing special:

public class Flight {

String flight_no, departure_date, departure;
int price;

The rest of the bean is just a bunch of getters and setters.