Chris Beams opened SPR-8034 and commented

As a convenience to avoids the need to create a separate compilation unit (.java file) for @FeatureConfiguration types, allow users to do the following:

@Configuration
public class MyBeans {
    @Bean
    public DataSource dataSource() { ... }
    
    @FeatureConfiguration
    static class MyFeatures {
        @Feature
        public ComponentScanSpec scan() {
            return new ComponentScanSpec("com.bank.app");
        }
    }
}

In such a case, no explicit registration or import of the @FeatureConfiguration class would be necessary. Simply bootstrapping the container with

new AnnotationConfigApplicationContext(MyBeans.class);

Would be enough.

Issue Links:

• Automatically detect and register nested @Configuration classes [SPR-8186] #12837 Automatically detect and register nested @Configuration classes