Wait for Cloud Firestore task result

I'm trying to develop a method to access the Cloud Firestore, read a user's data and return the map associated to it. For what I understand, it is not waiting for the success/failure listener, and I already tried changing it for a complete listener but the result is the same. It skips through the listeners.
I know that this is a Assynchronous process, but I need to receive the data to show them on the Activity that calls the method.

Settings Activity:

    @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.binding = ActivitySettingsBinding.inflate(getLayoutInflater());
this.fbUtils = new FirebaseHandler(this);
setContentView(binding.getRoot());
}
@Override
protected void onStart() {
super.onStart();
User user = fbUtils.getCurrentUser();
if (user == null) {
findUserOrLogout();
} else {
showUserData(user);
}
}

FirebaseHandler

    public User getCurrentUser() {
FirebaseUser user = auth.getCurrentUser();
if (user != null) {
this.userMap = getUserDBInfo(user.getUid());
this.profilePic = getUserPic(user.getUid());
if (this.userMap != null && this.profilePic != null) {
return new User(user, userMap, profilePic);
}
}
return null;
}
private Map<String, Object> getUserDBInfo(String uid) {
Log.d(TAG, "Getting user info for user '" + uid+"'");
DocumentReference docRef = db.collection("users").document(uid);
final Map<String, Object>[] userMap = new Map[]{null};
final boolean[] done = new boolean[]{false};
docRef.get().addOnSuccessListener(new OnSuccessListener<DocumentSnapshot>() {
@Override
public void onSuccess(DocumentSnapshot documentSnapshot) {
if (documentSnapshot.exists()) {
Log.d(TAG, "DocShot: " + documentSnapshot);
userMap[0] = documentSnapshot.getData();
} else {
Log.d(TAG, "User's document not found");
}
}
}).addOnFailureListener(new OnFailureListener() {
@Override
public void onFailure(@NonNull Exception e) {
Log.d(TAG, "Couldn't get the Document");
MainActivity.showToast("Couldn't get the Document", activity.getApplicationContext());
}
});
return userMap[0];
}

Am I doing something wrong in my code, or is there anything I can change to make this work?

Thanks in advance.

You have to change the rules inside the Firebase console to allow a write operation.

You've to follow the steps given below to do so:-

1. Open your Firebase Console and navigate to Database.

2. There go to the Rules tab and edit the rules to following:-

{
"rules": {
".read": true,
".write": true
}
}

This will allow you to perform write operations on your DB.

Please let me know if you will need screenshots.

If your database requires an authenticated user to read and write the database then do use the other answer here. It will create a massive security hole that allows for anyone with an internet connection to fully read and write the database.

Your code should instead ensure that a user is signed in before trying to make any queries. This made possible by using an auth state listener to get a callback when the user is signed in. Only after this callback is invoked with a valid user object is it safe to make a query that requires authentication.