Not able to read values using @Value in application.yaml in Springboot

I'm using Spring boot - 2.3.3.RELEASE. There are some values in application.yaml which I'm trying to inject in the classes using @Value annotation. But for some reason, they are not loading up. The result should be that, in SendPhoneByPhoneNumbers.java, we should be able to read notificationServiceURL from application.yaml.

Note- I'm using Factory and Strategy pattern. This project is going to be used as a Library for other projects to import and use the methods exposed by Service layer.

Here is the folder structure: https://i.stack.imgur.com/jpbNj.jpg
I'm trying to test by running Demo.java in Debug mode to see how the actual values looks like.

application.yaml

notificationService:
  url: "https://someURL.com"

Demo.java

@EnableAutoConfiguration(exclude={DataSourceAutoConfiguration.class})
@SpringBootApplication
public class Demo {

    public static void main(String[] args) {

        SpringApplication.run(Demo.class, args);

        String title="Title";
        String message="message";
        List<String> phoneNumbers = new ArrayList<>();
        phoneNumbers.add("333-222-1111");
        PhoneService phoneService = new PhoneService();
        phoneService.sendNotificationByPhoneNumbers(title, message, phoneNumbers);

    }
}

PhoneService.java

@Service
public class PhoneService {

    PhoneServiceImpl notificationServiceImpl = new PhoneServiceImpl();

    public void sendNotificationByPhoneNumbers(String title, String message, List<String> phoneNumbers) {
        notificationServiceImpl.sendNotificationByPhoneNumbers(title, message, phoneNumbers);
    }
}

PhoneServiceImpl.java

@Slf4j
@Component
public class PhoneServiceImpl {

    @Value("${notificationService.url}")
    String url;

    public void sendNotificationByPhoneNumbers(String title, String message, List<String> phoneNumbers) {
        PhoneContext phoneContext = new PhoneContext(new SendPhoneByPhoneNumbers(url));
        phoneContext.notify(title, message, phoneNumbers);
    }

}

PhoneContext.java

public class PhoneContext {

    private PhoneStrategy phoneStrategy;

    public PhoneContext(PhoneStrategy phoneStrategy){
        this.phoneStrategy = phoneStrategy;
    }

    public void notify(String title, String message, List<String> employees){
        phoneStrategy.sendNotification(title, message, employees);
    }
}

PhoneStrategy.java

public interface PhoneStrategy {

   public void sendNotification(String title, String message, List<String> listOfEmployeeIdGroupNamePhoneNumbers);
}

SendPhoneByPhoneNumbers.java

@Slf4j
public class SendPhoneByPhoneNumbers implements PhoneStrategy {

    RestTemplate restTemplate;
    String notificationServiceURL;
    BuildHttpRequest buildHttpRequest;

    public SendPhoneByPhoneNumbers(String notificationServiceURL) {
        this.notificationServiceURL = notificationServiceURL;
        this.restTemplate = new RestTemplate();
        this.buildHttpRequest = new BuildHttpRequest();
    }

    @Async
    public void sendNotification(String title, String message, List<String> phoneNumbers) {
        SmsMessage smsMessage= new SmsMessage(title, message, phoneNumbers, Collections.emptyList(), Collections.emptyList());

        try {
            HttpHeaders headers = new HttpHeaders();
            headers.set("idToken", buildHttpRequest.getNewToken());

            HttpEntity<SmsMessage> newRequest = new HttpEntity<>(smsMessage, headers);
            restTemplate.postForObject(notificationServiceURL + "/someUrl", newRequest, String.class);
        } catch (Exception e) {
            log.error(e.getMessage());
        }
    }
}

Also, if you guys have any suggestions on modifying the code/structure in an way to make it better, please do suggest.

Thanks in advance.

PhoneService phoneService = new PhoneService();

Since PhoneService that you are using is not a managed bean by spring container, the values are not being injected.

Code Improvement and FIX

String title="Title";
        String message="message";
        List<String> phoneNumbers = new ArrayList<>();
        phoneNumbers.add("333-222-1111");
        // PhoneService phoneService = new PhoneService();
        phoneService.sendNotificationByPhoneNumbers(title, message, phoneNumbers);

Move this code to a class implementing CommanLineRunner or ApplicationRunner and override corresponding run(). In this class, you could @Autowire PhoneService rather than manually instantiating it. Also note that you have to mark this class with @Component

Other minor suggested changes:

1. You can make SendPhoneByPhoneNumbers class a singleton. If there are multiple implementions, use @Qualifier
2. Both RestTemplate and BuildHttpRequest could be created using @Bean annotation.
3. Since you are using lombok, using @RequiredArgsConstructor could also be considered.