When a class is decorated with @Compoment,
or a more specialized annotation (@Controller, @Service, ...)
and this class has only one constructor,
the use of @Autowired on this constructor can be made optional:
Spring has only one way to instantiate a bean of this class: using this constructor and injecting beans and/of values in the parameter of this constructor.
This woudl make the class more simple and 'Pojo'.
You find a lot of these classes in Spring Pet Clinic and Spring Sagan.