Error for creating multiples Beans : Is there an unresolvable circular reference?

Question

When I'm trying to implement to login part of my API and try to run it, I got many errors like bellow:

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2021-02-12 02:23:23.314 ERROR 25840 --- [           main] o.s.boot.SpringApplication               : Application run failed

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'userController' defined in file [C:\Users\chafy\Desktop\cub\back\target\classes\com\cesi\cuberil\controllers\UserController.class]: Unsatisfied dependency expressed through constructor parameter 0; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'webSecurityConfig' defined in file [C:\Users\chafy\Desktop\cub\back\target\classes\com\cesi\cuberil\security\config\WebSecurityConfig.class]: Unsatisfied dependency expressed through constructor parameter 0; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'userService' defined in file [C:\Users\chafy\Desktop\cub\back\target\classes\com\cesi\cuberil\services\UserService.class]: Unsatisfied dependency expressed through constructor parameter 2; nested exception is org.springframework.beans.factory.BeanCurrentlyInCreationException: Error creating bean with name 'org.springframework.security.authenticationManager': Requested bean is currently in creation: Is there an unresolvable circular reference?
    at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:800) ~[spring-beans-5.3.3.jar:5.3.3]
    at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:229) ~[spring-beans-5.3.3.jar:5.3.3]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:1356) ~[spring-beans-5.3.3.jar:5.3.3]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1206) ~[spring-beans-5.3.3.jar:5.3.3]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:571) ~[spring-beans-5.3.3.jar:5.3.3]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:531) ~[spring-beans-5.3.3.jar:5.3.3]
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335) ~[spring-beans-5.3.3.jar:5.3.3]
Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'webSecurityConfig' defined in file [C:\Users\chafy\Desktop\cub\back\target\classes\com\cesi\cuberil\security\config\WebSecurityConfig.class]: Unsatisfied dependency expressed through constructor parameter 0; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'userService' defined in file [C:\Users\chafy\Desktop\cub\back\target\classes\com\cesi\cuberil\services\UserService.class]: Unsatisfied dependency expressed through constructor parameter 2; nested exception is org.springframework.beans.factory.BeanCurrentlyInCreationException: Error creating bean with name 'org.springframework.security.authenticationManager': Requested bean is currently in creation: Is there an unresolvable circular reference?
    at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:800) ~[spring-beans-5.3.3.jar:5.3.3]
    at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:229) ~[spring-beans-5.3.3.jar:5.3.3]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:1356) ~[spring-beans-5.3.3.jar:5.3.3]
Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'userService' defined in file [C:\Users\chafy\Desktop\cub\back\target\classes\com\cesi\cuberil\services\UserService.class]: Unsatisfied dependency expressed through constructor parameter 2; nested exception is org.springframework.beans.factory.BeanCurrentlyInCreationException: Error creating bean with name 'org.springframework.security.authenticationManager': Requested bean is currently in creation: Is there an unresolvable circular reference?
    at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:800) ~[spring-beans-5.3.3.jar:5.3.3]
    at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:229) ~[spring-beans-5.3.3.jar:5.3.3]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:1356) ~[spring-beans-5.3.3.jar:5.3.3]
Caused by: org.springframework.beans.factory.BeanCurrentlyInCreationException: Error creating bean with name 'org.springframework.security.authenticationManager': Requested bean is currently in creation: Is there an unresolvable circular reference?
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.beforeSingletonCreation(DefaultSingletonBeanRegistry.java:355) ~[spring-beans-5.3.3.jar:5.3.3]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:227) ~[spring-beans-5.3.3.jar:5.3.3]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333) ~[spring-beans-5.3.3.jar:5.3.3]

I'm new to Spring se I don't really know what the error means.

here the following classes:

UserController:

@RestController
@RequestMapping(path="api/v1/user")
@AllArgsConstructor
@CrossOrigin(origins = "*")
public class UserController implements Routes {

    private final AuthenticationManager authenticationManager;
    private final RegistrationService registrationService;

    @PostMapping(registration)
    public String register(@RequestBody RegistrationRequest request){
        return registrationService.register(request);
    }

    @PostMapping(login)
    public ResponseEntity<?> login(@Valid @RequestBody LoginRequest loginRequest) {
        Authentication authentication = authenticationManager.authenticate(
                new UsernamePasswordAuthenticationToken(loginRequest.getUserName(), loginRequest.getPassword()));

        SecurityContextHolder.getContext().setAuthentication(authentication);
        User myUserDetails = (User) SecurityContextHolder.getContext().getAuthentication().getPrincipal();
        List<String> roles = myUserDetails.getAuthorities().stream()
                .map(item -> item.getAuthority())
                .collect(Collectors.toList());

        return ResponseEntity.ok("OKKKK CONNECté");
    }

    @PostMapping(resetPassword)
    public String resetPassword() {
        return "Password reset";
    }


    @GetMapping(path = confirm)
    public String confirm(@RequestParam("token") String token) {
        return registrationService.confirmToken(token);
    }
}

UserService:

@Service
@AllArgsConstructor
public class UserService implements UserDetailsService {


    private final static String USER_NOT_FOUND_MESSAGE = "user with email %s not found";
    private final UserRepository userRepository;
    private final ConfirmationTokenService confirmationTokenService;
    private final AuthenticationManager authenticationManager;

    @Override
    public UserDetails loadUserByUsername(String email)
            throws UsernameNotFoundException {
        return userRepository.findByEmail(email)
                .orElseThrow(() -> new UsernameNotFoundException(String.format(USER_NOT_FOUND_MESSAGE, email)));
    }

    public String signUpUser(User user) {
        boolean userExists = userRepository.findByEmail(user.getEmail()).isPresent();
        if (userExists) {
            throw new IllegalStateException("Email already taken");
        }
        String encodedPassword = bCryptPasswordEncoder().encode(user.getPassword());
        user.setPassword(encodedPassword);
        userRepository.save(user);
        String token = UUID.randomUUID().toString();
        //TODO: Send Confirmation Token
        ConfirmationToken confirmationToken = new ConfirmationToken(
                token,
                LocalDateTime.now(),
                LocalDateTime.now().plusMinutes(15),
                user
        );

        confirmationTokenService.saveConfirmationToken(confirmationToken);

        //TODO: SEND EMAIL

        return "Token: " + token + "\nFirstname: " + user.getFirstName() + "\nLastname: " + user.getLastName() +
                "\nUsername: " + user.getUsername() + "\nEmail: " + user.getEmail();
    }

    public int enableAppUser(String email) {
        return userRepository.enableAppUser(email);
    }

    public AuthenticationResponse login(LoginRequest loginRequest) {
        Authentication authenticate = authenticationManager.authenticate(new UsernamePasswordAuthenticationToken(loginRequest.getUserName(),
                loginRequest.getPassword()));
        SecurityContextHolder.getContext().setAuthentication(authenticate);
        return new AuthenticationResponse(loginRequest.getUserName());
    }

    public BCryptPasswordEncoder bCryptPasswordEncoder(){
        return new BCryptPasswordEncoder();
    }
}

WebSecurityConfig:

@Configuration
@AllArgsConstructor
@EnableWebSecurity
public class WebSecurityConfig extends WebSecurityConfigurerAdapter {
    private final UserService userService;
    private final BCryptPasswordEncoder bCryptPasswordEncoder;

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http.csrf().disable()
                .authorizeRequests().antMatchers("/api/v*/**").permitAll()
                .anyRequest()
                .authenticated().and()
                .formLogin();

    }
@Override
    public void configure(AuthenticationManagerBuilder authenticationManagerBuilder) throws Exception {
        authenticationManagerBuilder.userDetailsService(userService)
                .passwordEncoder(passwordEncoder());
    }

    @Bean
    PasswordEncoder passwordEncoder() {
        return new BCryptPasswordEncoder();
    }

    @Bean
    @Override
    public AuthenticationManager authenticationManagerBean() throws Exception {
        return super.authenticationManagerBean();
    }
}

I don't understand the meaning of: Is there an unresolvable circular reference? I've remove all @Autowired annotationd because Spring will attempt to find a bean of matching type. I through that was the problem but no.

Answer 1

The Spring uses de Inversion of Control principle, that means you don't have to create your objects and you can add them through Dependency Injection.

When you inject dependencies in the WebSecurityConfig through Lombok's @AllArgsConstructor constructor you're telling to Spring inject those beans. At that phase, it doesn't have the required bean "AuthenticationManager" for the UserService bean.

The solution is to inject the UserService through method's parameter using autowired

@Override
@Autowired
public void configure(AuthenticationManagerBuilder authenticationManagerBuilder, UserService userService) throws Exception {
    authenticationManagerBuilder.userDetailsService(userService)
            .passwordEncoder(passwordEncoder());
}

and remove the class field userService.

---

Wrong way

@SpringBootApplication
public class DemoApplication {

    UserService userService;

    public DemoApplication(UserService userService) {
        this.userService = userService;
    }

    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }

    @Bean
    public TestService testService() {
        return new TestService();
    }
}

Log

Description:

The dependencies of some of the beans in the application context form a cycle:

┌─────┐
|  demoApplication
↑     ↓
|  userService defined in file [...\target\classes\com\example\demo\UserService.class]
└─────┘

---

Solution

@SpringBootApplication
public class DemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }

    @Autowired
    public void userService(UserService userService) {
        System.out.println("UserService Injected: " + userService);
    }

    @Bean
    public TestService testService() {
        return new TestService();
    }
}

@Service
public class UserService {
    
    public UserService(TestService testService) {
        System.out.println("User Service created using: " + testService);
    }
}

public class TestService {
    public TestService() {
        System.out.println("TestService created");
    }

    @Override
    public String toString() {
        return "Test Service";
    }
}

Log

TestService created
User Service created using: Test Service
UserService Injected: com.example.demo.UserService@29629fbb