I try to read the user's data from Firebase Realtime Database but it always returns null. Here is my code:

```
    final FirebaseDatabase database = FirebaseDatabase.getInstance();
    DatabaseReference ref = database.getReference();
    ref.child("shop").child("Users").child(mAuth.getCurrentUser().getUid()).addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
                Users user = dataSnapshot.getValue(Users.class);
        }

        @Override
        public void onCancelled(DatabaseError error) {
            // Failed to read value
            Log.w("1abc", "Failed to read value.", error.toException());
        }
    });

```

Here is the Users class:

```
public class Users {

    private String full_name;
    private String UID;
    private String email;

    public Users(String newemail, String newUID, String newfull_name) {
        // ...
        this.email=newemail;
        this.full_name=newfull_name;
        this.UID=newUID;
    }
    public Users() {
        // ...

    }
}

```

And here is my database tree:
[![enter image description here](https://i.stack.imgur.com/IqQAN.jpg)](https://i.stack.imgur.com/IqQAN.jpg)

Can someone tell me where am i wrong? Thanks in advance.