JPA doesn't get OneToMany mapped entity

Question

I made a service which has saving function:

ClientService.java

@Transactional
public ClientDTO signUp(ClientSignupDTO clientSignupDTO) {

    Client client = Client.builder()
            .clientID(clientSignupDTO.getClientID())
            .clientPassword(passwordEncoder.encode(clientSignupDTO.getClientPassword()))
            .clientNickname(clientSignupDTO.getClientNickname())
            .clientActivated(true)
            .build();

    client = clientRepository.save(client);
    clientAuthorityRepository.save(new ClientAuthority(client, authorityRepository.getById("ROLE_CLIENT")));

    client = clientRepository.findOneWithAuthoritiesByClientID(client.getClientID()).orElseThrow(() -> new IllegalStateException("Client does not exist"));

    log.debug("{}", client.getAuthorities()); //This line throws NullPointerException

    return new ClientDTO(client);
}

I saved Client entity and ClientAuthority entity with saved Client 's ID for M:N mapping.
But when I try to find Client in same function, JPA returns Client without ClientAuthority .

Client.java

@Entity
@Table(name = "client")
@Getter
@Setter
@Builder
@NoArgsConstructor
public class Client {

    @Id
    @Column(name = "id")
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Column(name = "client_id", length = 50)
    private String clientID;

    @Column(name = "client_password")
    private String clientPassword;

    @Column(name = "client_nickname", length = 50)
    private String clientNickname;

    @Column(name = "client_since", nullable = false, updatable = false, insertable = false, columnDefinition = "TIMESTAMP DEFAULT CURRENT_TIMESTAMP")
    private Date clientSince;

    @Column(name = "client_activated")
    private boolean clientActivated;

    @JsonIgnore
    @OneToMany(mappedBy = "client")
    private Set<ClientAuthority> clientAuthorities;

    @JsonProperty("authorities")
    public Set<Authority> getAuthorities() {
        return clientAuthorities.stream().map(ClientAuthority::getAuthority).collect(Collectors.toSet());
    }

    public Client(Long id, String clientID, String clientPassword, String clientNickname, Date clientSince, boolean clientActivated, Set<ClientAuthority> clientAuthorities) {
        this.id = id;
        this.clientID = clientID;
        this.clientPassword = clientPassword;
        this.clientNickname = clientNickname;
        this.clientSince = clientSince;
        this.clientActivated = clientActivated;
        this.clientAuthorities = clientAuthorities;
    }
}

ClientAuthority.java

@Entity
@Table(name = "client_authority")
@Getter
@Setter
@Builder
@NoArgsConstructor
public class ClientAuthority {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "client_authority_id")
    private Long clientAuthorityID;

    @ManyToOne
    @JoinColumn(name = "client_id")
    private Client client;

    @ManyToOne
    @JoinColumn(name = "authority_name")
    private Authority authority;

    public ClientAuthority(Long clientAuthorityID, Client client, Authority authority) {
        this.clientAuthorityID = clientAuthorityID;
        this.client = client;
        this.authority = authority;
    }

    public ClientAuthority(Client client, Authority authority) {
        this.client = client;
        this.authority = authority;
    }
}

Repository that I used to find client is Spring Data JPA repository.

ClientRepository.java

@Repository
public interface ClientRepository extends JpaRepository<Client, Long> {
    Optional<Client> findOneWithAuthoritiesByClientID(String clientID);
}

Since clientAuthorities inside Client that returned by findOneWithAuthoritiesByClientID is null, Client.getAuthorities returns NullPointerException .
Other properties such as clientID , clientNickname , etc. works fine but only clientAuthorities is null.

How can I get Client with Set<ClientAuthority> after save them?

Thanks.

---

Edit #1

Edited all save into saveAndFlush in function signUp . But it keeps throwing NullPointerException .

@Transactional
public ClientDTO signUp(ClientSignupDTO clientSignupDTO) {

    Client client = clientRepository.saveAndFlush(Client.builder()
            .clientID(clientSignupDTO.getClientID())
            .clientPassword(passwordEncoder.encode(clientSignupDTO.getClientPassword()))
            .clientNickname(clientSignupDTO.getClientNickname())
            .clientActivated(true)
            .build());

    log.debug("{}, {}, {}, {}", client.getId(), client.getClientID(), client.getClientNickname(), client.getClientSince());

    clientAuthorityRepository.saveAndFlush(new ClientAuthority(client, authorityRepository.getById("ROLE_CLIENT")));

    client = clientRepository.findOneWithAuthoritiesByClientID(client.getClientID()).orElseThrow(() -> new IllegalStateException("Client does not exist"));

    log.debug("{}, {}, {}, {}", client.getClientID(), client.getClientNickname(), client.getClientSince(), client.getAuthorities());

    return new ClientDTO(client);
}

The log is:

Hibernate: insert into client (client_activated, client_id, client_nickname, client_password) values (?, ?, ?, ?)
2022-02-25 14:22:07.986 DEBUG 16684 --- [nio-8080-exec-3] c.d.s.service.ClientService              : 4, test, test, null
Hibernate: insert into client_authority (authority_name, client_id) values (?, ?)
Hibernate: select client0_.id as id1_1_, client0_.client_activated as client_a2_1_, client0_.client_id as client_i3_1_, client0_.client_nickname as client_n4_1_, client0_.client_password as client_p5_1_, client0_.client_since as client_s6_1_ from client client0_ where client0_.client_id=?
2022-02-25 14:22:08.071 ERROR 16684 --- [nio-8080-exec-3] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is java.lang.NullPointerException] with root cause

java.lang.NullPointerException: null
    at com.devjaewoo.springtest.entity.Client.getAuthorities(Client.java:46) ~[classes/:na]

When I test findOneWithAuthoritiesByClientID function with sample data (with data.sql file) outside of signUp function, It works fine.

Why doesn't it work properly only inside of signUp function?

Answer 1

you may need to saveAndFlush

but I would recommend

final var client = clientRepository
  .saveAndFlush(Client
    .builder()
    .clientID(clientSignupDTO.getClientID())
    ...
    .build());

So you immediately get the managed copy.