I have more than 300+ clients in my application and I’m using Firebase Cloud Messaging API to send push notifications. Recently I have migrated to FCM V1 and used Firebase Admin SDK. We are using a single service for sending push notifications.Since we cannot initialize Firebase apps for each client when starting the service, I have initialized firebase app when sending the push notification. To avoid duplications of firebase app initialization I have used below code snippet. But still I’m getting “FirebaseApp name [project-id] already exists!” error.

private FirebaseApp getFirebaseApp(final String serverKeyJson, final String projectId) throws IOException {
        for (final FirebaseApp app : FirebaseApp.getApps()) {
            if (app.getOptions().getProjectId().equals(projectId)) {
                return app;
            }
        }

        final ByteArrayInputStream credentialsStream = new ByteArrayInputStream(serverKeyJson.getBytes());

        final FirebaseOptions options = FirebaseOptions.builder()
            .setCredentials(GoogleCredentials.fromStream(credentialsStream))
            .setProjectId(projectId)
            .build();

        return FirebaseApp.initializeApp(options, projectId);
    }

Push-notification service is based on Spring-boot.

How to fix this issue?