Why I can replace @RestContoller with @Component and it still works?

Question

Can someone explain why replacement of RestController annotation with Component has no any visible effect in my case? My controller:

@RestController
@RequestMapping("/api/employees")
public class EmployeeController {

    @Autowired
    EmployeeService employeeService;

    @PostMapping("")
    public Employee saveEmployee(@Valid @RequestBody Employee employee) {
        return employeeService.save(employee);
    }


    ...

This works in the same way:

@Component
@ResponseBody
@RequestMapping("/api/employees")
public class EmployeeController {

...

Answer 1

The not-in-depth description of individual annotations would be:

• @RequestMapping registers your class for servlet mapping.
• @Component registers your class for dependency injection.
• @ResponseBody will add the return value of the method to the HTTP response body.

1st case - @RestController registers your class for DI and adds @ResponseBody annotation to it, @RequestMapping registers class for servlet mapping.

2nd case - @Component registers your class for DI and you added a manual @ResponseBody annotation to it, @RequestMapping registers class for servlet mapping.

Both of the cases above do the same thing, so that's why it 'just works'.