What components or objects can be available or interact during the execution of a method annotated with PostConstruct in Spring?

The method annotated with @PostConstruct in Spring is called after Spring has created the bean and injected all dependencies (via constructor, setters, or fields). At this point:

• All dependencies annotated with @Autowired or injected by other means are initialized and ready to use.
• The Spring context, if injected into the bean, is also available.

Therefore, in the @PostConstruct method, you can perform additional initialization that requires all dependencies to be present. For example, you can configure internal states of the object, verify the correctness of injected components, or start some processes.

Example:

@Component
public class MyService {
    @Autowired
    private Dependency dep;

    @PostConstruct
    public void init() {
        dep.setup(); // can safely use, as dep is already injected
    }
}