FATAL EXCEPTION: Firebase-Messaging-Intent-Handle Выбрасывает из приложения после написания сообщения

FATAL EXCEPTION: Firebase-Messaging-Intent-Handle
    Process: com.example.blum, PID: 20321
    java.lang.NullPointerException: Attempt to invoke virtual method 'boolean java.lang.String.equals(java.lang.Object)' on a null object reference
        at Notifications.MyFirebaseMessaging.onMessageReceived(MyFirebaseMessaging.java:30)
        at com.google.firebase.messaging.FirebaseMessagingService.dispatchMessage(com.google.firebase:firebase-messaging@@20.3.0:74)
        at com.google.firebase.messaging.FirebaseMessagingService.passMessageIntentToSdk(com.google.firebase:firebase-messaging@@20.3.0:44)
        at com.google.firebase.messaging.FirebaseMessagingService.handleMessageIntent(com.google.firebase:firebase-messaging@@20.3.0:27)
        at com.google.firebase.messaging.FirebaseMessagingService.handleIntent(com.google.firebase:firebase-messaging@@20.3.0:17)
        at com.google.firebase.messaging.EnhancedIntentService.lambda$processIntent$0$EnhancedIntentService(com.google.firebase:firebase-messaging@@20.3.0:43)
        at com.google.firebase.messaging.EnhancedIntentService$$Lambda$0.run(Unknown Source:6)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
        at com.google.android.gms.common.util.concurrent.zza.run(Unknown Source:6)
        at java.lang.Thread.run(Thread.java:923)

import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.media.RingtoneManager;
import android.net.Uri;
import android.os.Bundle;

import androidx.annotation.NonNull;
import androidx.core.app.NotificationCompat;

import com.example.blum.MessageActivity;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;
import com.google.firebase.messaging.FirebaseMessagingService;
import com.google.firebase.messaging.RemoteMessage;

public class MyFirebaseMessaging extends FirebaseMessagingService {

    @Override
    public void onMessageReceived(@NonNull RemoteMessage remoteMessage) {
        super.onMessageReceived(remoteMessage);

        String sented = remoteMessage.getData().get("sented");

        FirebaseUser firebaseUser = FirebaseAuth.getInstance().getCurrentUser();

        if (firebaseUser != null && sented.equals(firebaseUser.getUid())) {
            sendNotification(remoteMessage);
        }
    }

    private void sendNotification(RemoteMessage remoteMessage) {

        String user = remoteMessage.getData().get("user");
        String icon = remoteMessage.getData().get("icon");
        String title = remoteMessage.getData().get("title");
        String body = remoteMessage.getData().get("body");

        RemoteMessage.Notification notification = remoteMessage.getNotification();
        int j = Integer.parseInt(user.replaceAll("[\\D]", ""));
        Intent intent = new Intent(this, MessageActivity.class);
        Bundle bundle = new Bundle();
        bundle.putString("userid", user);
        intent.putExtras(bundle);
        intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        PendingIntent pendingIntent = PendingIntent.getActivity(this, j, intent, PendingIntent.FLAG_ONE_SHOT);

        Uri defaultSound = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
        NotificationCompat.Builder builder = new NotificationCompat.Builder(this)
                .setSmallIcon(Integer.parseInt(icon))
                .setContentTitle(title)
                .setContentText(body)
                .setAutoCancel(true)
                .setSound(defaultSound)
                .setContentIntent(pendingIntent);
        NotificationManager noti = (NotificationManager)getSystemService(Context.NOTIFICATION_SERVICE);

        int i = 0;
        if (j > 0) {
            i = j;
        }

        noti.notify(i, builder.build());
    }
}

if (firebaseUser != null && sented.equals(firebaseUser.getUid()))