// Which SOLID principle is violated here?
class EmailSender {
    public void sendEmail(String recipient, String message) {
        // Code to send email
        System.out.println("Sending email to: " + recipient);
        System.out.println("Message: " + message);
    }
}

class NotificationService {
    private EmailSender emailSender;

    public NotificationService() {
        emailSender = new EmailSender();
    }

    public void sendNotification(String recipient, String message) {
        emailSender.sendEmail(recipient, message);
    }
}