@Value annotation not working in constructor

Question

I have an issue where Spring @Value annotation not working in the constructor.

I have this Email class that is reading some email related configuration.

In the constructor, if I put a break-point the values are empty

But if I call the sendEmail method, there are values.

The other class:

@Autowired
Email sender;

Email class:

@Component
public class Email{

    @Value("${TO_EMAIL}")
    private String toEmail;

    public Email() {        
        // Here toEmail is null 
    }

    public void sendEmail(String subject, String body) {
        // Here toEmail has value
    }
}

Answer 1

As far I remember, the value injection occurs after the constructor call.

Try to change your constructor to this:

public Email(@Value("${TO_EMAIL}") String toEmail) { 
   this.toEmail = toEmail;
}

Answer 2

The value injection occures after the constructor call, to solve this in your case, you can leave the constructor empty. And add a method annotated with "@PostConstructor". This way, the empty constructor will be called, then the values will be injected, then the @PostConstructor method will be called.