Autowired not happening for bean with @Async method

it helps some times Create a new Interface extending UserDetailsService and add your desired method.

public class MyUserDetailsService extends UserDetailsService {
    ...
    public SpringboardAuthenticationUser getSpringboardAuthenticationUser(final User domainUser); 
    ... 
}

public class MyUserDetailsServiceImpl implements MyUserDetailsService {

    @Override
    public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {

    }

    @Override
    public SpringboardAuthenticationUser getSpringboardAuthenticationUser(final User domainUser){
        ... 
        //Your logic here.
    }
}

private MyUserDetailsService userDetailsService;

Does that help Because you might not have any Inheritance in your Bean Definition. Super-class members, loaded into memory during creation of respective child-class according to the Java OOP model, is not going to be referencing your explicit Spring Bean. I. E. you have Java inheritance, but you should also define Bean Inheritance, if you'd want to achieve what you ask in your question. Otherwise, your explicit component is not necessarily the one where your "child" component inherits from.
This is also the answer for your

seems to work fine About @Bean in Spring