Структура сущности JPA

У меня есть страница входа, где данные будут извлечены из базы данных

Пользователь

@Setter
@Getter
@Entity
@Table(name = "USER_DETAILS")
public class User implements Serializable {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "USER_ID")
    private Long id;

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

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

    @Transient
    private Set<Role> roles;


    @ManyToMany
    @JoinTable(name = "USER_ROLE", joinColumns = @JoinColumn(name = "USER_ID"), inverseJoinColumns = @JoinColumn(name = "ROLE_ID"))
    public Set<Role> getRoles() {
        return roles;
    }

    public void setRoles(Set<Role> roles) {
        this.roles = roles;
    }

}

Роль

@Setter
@Getter
@Entity
@Table(name = "USER_ROLE")
public class Role implements Serializable {

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

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


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

    @Transient
    private Set<User>users;


    @ManyToMany(mappedBy = "roles")
    public Set<User> getUsers() {
        return users;
    }

    public void setUsers(Set<User> users) {
        this.users = users;
    }
}

UserDetailServiceImpl

@Service
public class UserDetailsServiceImpl implements UserDetailsService {
    @Autowired
    private UserRepository userRepository;

    @Override
    @Transactional(readOnly = true)
    public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {
        User user = userRepository.findByUsername(username);
        System.out.println("Name "+user.getUserName());
        System.out.println("role is  "+user.getRoles());
        if (null == user) {
            throw new UsernameNotFoundException("No user present with username: " + username);
        }
        Set<GrantedAuthority> grantedAuthorities = new HashSet<>();
        for (Role role : user.getRoles()){
            grantedAuthorities.add(new SimpleGrantedAuthority(role.getUserName()));
        }

        return new org.springframework.security.core.userdetails.User(user.getUserName(), user.getUserPassword(), grantedAuthorities);
    }

}

Таблица

Роль

ROLE_ID | USER_NAME | ROLE_NAME
1             John     Admin

Пользователь

  USER_ID | USER_NAME  | USER_PASSWORD | USER_ROLE
      1         John            pass       Admin

Выход

Name John role is null 2018-03-12 00:52:06.362 ERROR 12563 --- [nio-8088-exec-8] w.a.UsernamePasswordAuthenticationFilter : An internal error occurred while trying to authenticate the user.

org.springframework.security.authentication.InternalAuthenticationServiceException: null

Я не могу понять значение роли. Что не так со структурой базы данных?