react native firebase fcm (firebase messaging cloud) + java spring boot: how to push notification

@Slf4j
@SpringBootTest
public class FcmTests {

    @Autowired
    FirebaseMessaging firebaseMessaging;

    @Test
    public void test1() throws FirebaseMessagingException {
        log.info("FCM Sending...");

        List<String> registrationTokens = Collections.singletonList("<your fcm token here>");

        // iOS Config
        Aps aps = Aps.builder()
                .setContentAvailable(true)
                .build();
        ApnsConfig apnsConfig = ApnsConfig.builder()
                .setAps(aps)
                .build();
        // android config
        AndroidConfig androidConfig = AndroidConfig.builder()
                .setPriority(AndroidConfig.Priority.HIGH)
                .build();

        MulticastMessage message = MulticastMessage.builder()
                .putData("title", "you can do everything")
                .putData("id", "1")
                .putData("body", "jumppp....")
                .setAndroidConfig(androidConfig)
                .setApnsConfig(apnsConfig)
                .addAllTokens(registrationTokens)
                .build();
        BatchResponse response = firebaseMessaging.sendMulticast(message);
        // See the BatchResponse reference documentation
        // for the contents of response.
        log.info("FCM Send success count=[{}]", response.getSuccessCount());
    }
}