I’m trying to develop an e-commerce website. Yesterday, I added Cart and CartItem to my project. I was able to create an address for the user before implementing the cart and cartItem functionality, but now I can’t.

Here are the relevant parts of my code related to the creating address issue,

The error which im dealing with is,

data: error: "Unsupported Media Type" message: "Content-Type 'application/json;charset=UTF-8' is not supported." path: "/address/createAddress/1" status: 415

@Entity
@Builder
@Getter
@Setter
@NoArgsConstructor
@AllArgsConstructor
@ToString
@Table(name = "Address")
public class Address {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "address_id", nullable = false, updatable = false)
    private Long id;

    ... (basic plain other variables such as firstName, lastName etc.)

    @ManyToOne
    @JoinColumn(name = "user_id")
    @JsonBackReference(value = "userAddresses")
    private User user;
}

@RestController
@RequestMapping("/address")
@RequiredArgsConstructor
public class AddressController {

    private final AddressService addressService;

    @PostMapping(path = "/createAddress/{id}", consumes = MediaType.APPLICATION_JSON_VALUE)
    public void createAddress(@PathVariable Long id, @RequestBody Address newAddress){
        addressService.createAddress(id, newAddress);
    }

    ...

AddressServiceImpl for creating an address

@Override
    public void createAddress(Long userId, Address newAddress) {
        User user = userRepository.findById(userId).orElseThrow(UserNotExistsException::new);
        List<Address> userAddresses = addressRepository.findAllByUserId(user.getId());
        if(userAddresses.isEmpty()){
            newAddress.setDefault(true);
        }
        newAddress.setUser(user);
        addressRepository.save(newAddress);
    }

And the other problem which I’m dealing is,

Failed to evaluate Jackson deserialization for type [[simple type, class com.project.supplement.entity.Address]]: com.fasterxml.jackson.databind.exc.InvalidDefinitionException: Cannot handle managed/back reference 'productFlavours': back reference type (java.util.List<com.project.supplement.entity.Flavour>) not compatible with managed type (com.project.supplement.entity.Flavour)

And here are the Product and Flavour entities,

@Entity
@Builder
@Getter
@Setter
@NoArgsConstructor
@AllArgsConstructor
@Table(name = "product")
public class Product {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "product_id", updatable = false, nullable = false)
    private Long id;

    ...

    @OneToMany(mappedBy = "product",cascade = CascadeType.ALL, fetch = FetchType.LAZY)
    @JsonManagedReference(value = "productNutritionFacts")
    private List<NutritionFacts> NutritionFacts;

    @ManyToOne(cascade = {CascadeType.PERSIST, CascadeType.DETACH, CascadeType.MERGE, CascadeType.REFRESH}, fetch = FetchType.LAZY)
    @JoinColumn(name = "category_id")
    @JsonBackReference(value = "productCategory")
    private Category category;

    @ManyToMany(cascade = {CascadeType.PERSIST, CascadeType.DETACH, CascadeType.MERGE, CascadeType.REFRESH}, fetch = FetchType.LAZY)
    @JoinTable(
            name = "product_flavour",
            joinColumns = @JoinColumn(name = "product_id"),
            inverseJoinColumns = @JoinColumn(name = "flavour_id")
    )
    @JsonBackReference(value = "productFlavours")
    private List<Flavour> flavours;

    @ElementCollection
    private List<String> ingredients;

    ...

    @ManyToMany(mappedBy = "favorites")
    private List<User> favoritedByUsers;
}

@Entity
@Getter
@Setter
@NoArgsConstructor
@AllArgsConstructor
@ToString
@Table(name = "flavour")
public class Flavour {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "flavour_id", updatable = false, nullable = false)
    private Long id;

    ...

    @ManyToMany(mappedBy = "flavours")
    @JsonManagedReference(value = "productFlavours")
    private List<Product> products;
}

For the address creation issue, I attempted to resolve it by adding the following consumes parameter, but it didn’t work
consumes = {“application/json;charset=UTF-8”, MediaType.APPLICATION_JSON_VALUE})

For the Jackson deserialization warning, I assigned the same value to all entities whose variables contain JsonBackReference and JsonManagedReference.