Spring @Autowire on Properties vs Constructor

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So since I’ve been using Spring, if I were to write a service that had dependencies I would do the following:

@Component
public class SomeService {
     @Autowired private SomeOtherService someOtherService;
}

I have now run across code that uses another convention to achieve the same goal

@Component
public class SomeService {
    private final SomeOtherService someOtherService;

    @Autowired
    public SomeService(SomeOtherService someOtherService){
        this.someOtherService = someOtherService;
    }
}

Both of these methods will work, I understand that. But is there some advantage to using option B? To me, it creates more code in the class and unit test. (Having to write constructor and not being able to use @InjectMocks)

Is there something I’m missing? Is there anything else the autowired constructor does besides add code to the unit tests? Is this a more preferred way to do dependency injection?

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