Why am I getting "Cannot resolve method 'equals(long)'"

Question

I am trying to build a REST API for an airport app. The issue is when I try to update my Airplane which has a many-to-one relationship with Airline, I try to check if the id of the airline which the airplane has a relationship with is equal to id provided during the request

This is the updateAirplane method:

    @Override
    public AirplaneDto updateAirplane(long airlineId, long airplaneId, AirplaneDto airplaneDto) {

        Airline airline = airlineRepository.findById(airlineId).orElseThrow(
                () -> new ResourceNotFoundException("Airline", "id", airlineId));

        Airplane airplane = airplaneRepository.findById(airplaneId).orElseThrow(
                () -> new ResourceNotFoundException("Airplane", "id", id));

        if(!airplane.getAirline().getId().equals(airline.getId())) {
            throw new AirportAPIException(HttpStatus.BAD_REQUEST, "Airplane does not belong to the          Airline");
        }

        return null

    }

The equals() above gives me "Cannot resolve method 'equals(long)'" error and further adds that "No candidates found for method call airplane.getAirline().getId().equals(airline.getId())."

This are the entities for airplane and airline respectively

    @Getter
    @Setter
    @AllArgsConstructor
    @NoArgsConstructor


    @Entity
    @Table(name = "airplane")
    public class Airplane {

        @Id
        @GeneratedValue(strategy = GenerationType.IDENTITY)
        private long id;
        private String aircraftRegistration;
        private String model;
        private long capacity;
        private String code;

        @ManyToOne(fetch = FetchType.LAZY)
        @JoinColumn(name = "airline_id", nullable = false)
        private Airline airline;
    }

    @Getter
    @Setter
    @AllArgsConstructor
    @NoArgsConstructor

    @Entity
    @Table(name = "Airline", uniqueConstraints = {@UniqueConstraint(columnNames = {"name"})})
    public class Airline {

        @Id
        @GeneratedValue(strategy = GenerationType.IDENTITY)
        private long id;
        private String name;
        private String headquarters;

        @OneToMany(mappedBy = "airline", cascade = CascadeType.ALL, orphanRemoval = true   )
        private Set<Airplane> airplanes = new HashSet<>();
    }

Answer 1

compare aireline and airplane Ids directly, with airplane.getAirline().getId !=airline.getId()