To provide a custom authentication provider in spring boot, do I need both of the following? and what is their difference?

AuthenticationManagerBuilder

HttpSecurity.authenticationProvider(...)

@Configuration
@EnableWebSecurity
public class SecurityConfig extends WebSecurityConfigurerAdapter{

  @Autowired
  private MyAuthenticationProvider myAuthenticationProvider;

  @Autowired
  @Override
  protected void configure(AuthenticationManagerBuilder auth) throws Exception {
      auth.authenticationProvider(myAuthenticationProvider);
  }

  // --------------- OR/AND ? ----------------
  @Override
  protected void configure(HttpSecurity http) throws Exception {
      http
      .authenticationProvider(myAuthenticationProvider)
      // ...
  }
}