Odtnhj

Faced with an incomprehensible problem for me: when I try to add a user role, the system jumps into reflection and throws out NullPointerException, instead of taking the Role value from DAO.

Entity:

@Entity
@Table(name = "users")
public class User implements Serializable {

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

@Column(name = "email", unique = true, nullable = false)
private String email;

@Column(name = "password", nullable = false)
private String password;

@Column(name = "first_name", length = 50, nullable = false)
private String firstName;

@Column(name = "last_name", length = 50, nullable = false)
private String lastName;

@Temporal(TemporalType.DATE)
@DateTimeFormat(pattern = "yyyy-MM-dd")
@Column(name = "birth_date", nullable = false)
private Date birthDate;

@ManyToOne
@JoinColumn(name = "role")
private Role role;

// getter & setter

and

@Entity
@Table(name = "roles")
public class Role implements Serializable {

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

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

@OneToMany(mappedBy = "role")
private Set<User> users;

// getter & setter

DAO (role):

@Repository
public class RoleDaoImpl extends AbstractGenericDao<Role> implements RoleDao 

private static final Logger LOG = Logger.getLogger(RoleDaoImpl.class.getName());

private static final String GET_ROLE_BY_NAME = "SELECT r FROM Role r WHERE r.name = :name";

@Override
public Role getRoleByName(String name) 
 Query query = getCurrentSession().createQuery(GET_ROLE_BY_NAME);
 query.setParameter("name", name);

 Role role = null;
 try 
 role = (Role) query.getSingleResult();
 catch (Exception e) 
 LOG.warn(e);
 
 return role;

Now I am trying to convert my userDto (it repeats entities, but does not contain id and role). Everything works until I try to add a user.addRole:

 public static User constructUser(UserDto userDto) 
 User user = new User();
 user.setEmail(userDto.getEmail());
 user.setPassword(userDto.getPassword());
 user.setFirstName(userDto.getFirstName());
 user.setLastName(userDto.getLastName());
 user.setBirthDate(DateConverter.convertDate(userDto.getBirthDate()));
 //user.setRole(roleDao.getRoleByName("ROLE_USER"));
 return user;

As soon as it comes to the commented line, the compiler does not enter the DAO, it goes into reflection and tries to do something there, and returns NullPointer.

Tell the inexperienced what could be the case and how to fix it. All this has a headache.

Tables exist, values are valid. Without an DTO (through an entity) everything works fine.