Spring How to autowire a component without using @Component or other derivatives

Question

I would like to autowire a component (still using the @Autowired annotation), but not require it to have the @Component (or other similar annotations) on it. How would I do this?

public class A {

    @Autowired
    private class B b;

}

@Component
public class B {

}

This would be convenient in order to allow autowiring of class A without requiring the creation of A, unless we needed it (in otherwise on the fly by reflection using the class name).

Answer 1

Injection and autowiring do not require @Component. They require beans. @Component states that the annotated type should have a bean generated for it. You can define beans in other ways: with a <bean> declaration in an XML context configuration, with a @Bean method in a @Configuration class, etc.

Your last sentence doesn't make much sense. You can't process injection targets in a bean without creating a bean. You also can't inject a bean without creating it. (Applied to scopes, bean may refer to the target source/proxy and not the actual instance.) Perhaps you want @Lazy.

Answer 2

I don't sure, If I correctly understood to your question. But if you want inject bean B without marking bean A via some annotation, or xml definition, you can use SpringBeanAutowiringSupport

public class A {

    @Autowired
    private class B b;

    public A{
        SpringBeanAutowiringSupport.processInjectionBasedOnCurrentContext(this); 
    }

}