How do I read values from a firebase realtime database for nested parent nodes via POJO classes?

Question

Here is my database:

I want to get data from stats.20201104.nutrients.protein which should be 2.

For all other nodes above it, I have been able to fetch data pretty nicely with a User POJO class setup. I can't seem to figure out a way to get the date vals, eg, 20201104, generically, it says the following in the run log which is expected:

No setter/field for 20201104 found on class com.example.nutrobud.ui.home.Stats

I know my Stats.java class is not setup correctly, how can I set this up so that I still maintain the same hierarchy of db nodes?

Here is my User class from User.java:

public class User {
    private String email;
    private String password;
    private String firstName;
    private String secondName;
    private int age;
    private String gender;
    private int weight;
    private List<String> ingredientsNo;
    private List<String> ingredientsYes;
    private List<Integer> ingredientsYesGoalsQty;
    private List<Integer> ingredientsYesTrackedQty;
    private int calorieGoalsQty;
    private int calorieTrackedQty;
    private Stats stats;

    //constructors

    //basic getter and setters for all data members
}

Stats.java, same directory as User.java:

public class Stats {
    private int caloriesTracked;
    private HashMap<String, Integer> nutrients;
    //constructors
    
    //basic getter and setters for all data members
}

Function to read data from db in activity:

db.child("users").addValueEventListener(new ValueEventListener() {
                @Override
                public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                    for(DataSnapshot snapshot: dataSnapshot.getChildren()){
                        User user = snapshot.getValue(User.class);
                        //do something with user
                    }
                }

                @Override
                public void onCancelled(@NonNull DatabaseError databaseError) {

                }
            });

Answer 1

You're close, but right now you have nothing in your POJOs capturing the 20201104 that the error message mentions. Since you can't know the actual keys, those will need to be a map.

So I think your:

private Stats stats;

Should actually be:

private Map<String, Stats> stats;