Setter not incrementing

@Entity
@Table(name = "bookings")
public class BookingEntity extends BaseEntity {

private int countBookings;

public int getCountBookings() {
        return countBookings;
    }

    public BookingEntity setCountBookings(int countBookings) {
        this.countBookings = countBookings;
        return this;
    }

@Service
public class BookingServiceImpl implements BookingService {

    private static int countBookings = 0;


 bookingEntity.setCountBookings(countBookings++);

.setCountBookings(bookingEntity.getCountBookings() + 1);

.setCountBookings(bookingEntity.incrementBookings());

(In bookingEntity):
  public int incrementBookings() {
     return this.countBookings++;
    }