Facing difficulty in multicast push notification in java spring boot

Question

My requirement is that i am doing a news portal project where i want to send latest added news to all the tokens which i have. The issue i am facing is that, i am not able to use sendMulticast function in fire base, I am able to send notification for one single token with the content. But when I try to send notification for multiple tokens there are issues. I have used the needed dependencies like, guava, firebase admin and all. I have taken the code from firebase console itself.

The error i got is:

Error Sending Notifications: Unexpected HTTP response with status: 404

404. That’s an error.

The requested URL /batch was not found on this server. That’s all we know.

Below is the code:

public class FireBaseMessagingService {
    
    private static final Logger log = LoggerFactory.getLogger(FireBaseMessagingService.class);

    @Autowired
    FirebaseMessaging firebaseMessaging;

    public String sendNotifications(NotificationMessagingFCM notifications) {

        String title = notifications.getTitle();
        String body = notifications.getBody();
        String image = notifications.getImage();
        List<String> recipientTokens = notifications.getRecipientToken();


        Notification notification = Notification.builder().setTitle(title).setBody(body).setImage(image).build();

        int batchSize = 500;
        int totalSuccess = 0;
        int totalFailure = 0;

        for (int i = 0; i < recipientTokens.size(); i += batchSize) {
            List<String> batchTokens = recipientTokens.subList(i, Math.min(i + batchSize, recipientTokens.size()));

            MulticastMessage message = MulticastMessage.builder()
                    .addAllTokens(batchTokens)
                    .setNotification(notification)
                    .build();

            try {
                BatchResponse response = firebaseMessaging.sendMulticast(message);
                totalSuccess += response.getSuccessCount();
                totalFailure += response.getFailureCount();

                if (response.getFailureCount() > 0) {
                    List<SendResponse> failures = response.getResponses();
                    for (int j = 0; j < failures.size(); j++) {
                        if (!failures.get(j).isSuccessful()) {
                            log.error("Failed to send notification to token: " + batchTokens.get(j) + " - "
                                    + failures.get(j).getException());
                        }
                    }
                }
            } catch (FirebaseMessagingException e) {
                log.error("Error sending notifications: " + e.getMessage(), e);
                return "Error Sending Notifications: " + e.getMessage();
            }
        }

        return "Success: " + totalSuccess + " messages were sent, Failures: " + totalFailure;
    }

}

Answer 1

From the Firebase documentation on sending messages to multiple devices:

Important: The send methods described in this section were deprecated on June 21, 2023, and will be removed in June 2024. For protocol, instead use the standard HTTP v1 API send method, implementing your own batch send by iterating through the list of recipients and sending to each recipient's token. For Admin SDK methods, make sure to update to the next major version. See the Firebase FAQ for more information.

So it seems that the method you rely on was removed last year. As the last few lines of that quote say, you'll want to update to the latest version of the Firebase Admin SDK and use the methods in there.