Isn't it possible to send it as an object when transferring Firebase DB?

Pass the following types corresponding to the available JSON types: String Long Double Boolean Map List Pass custom Java objects. The class that defines the object must have a default constructor that does not take arguments and a public getter for the property you want to specify.

public class User {

    public String username;
    public String email;

    public User() {
        // // Default constructor required for calls to DataSnapshot.getValue(User.class)
    }

    public User(String username, String email) {
        this.username = username;
        this.email = email;
    }
}

private void writeNewUser(String userId, String name, String email) {
    User user = new User(name, email);

    mDatabase.child("users").child(userId).setValue(user);
}

It is explained in the Firebase document, but if you write the same as above, there will be an error.

Caused by: com.google.firebase.database.DatabaseException: Found conflicting getters for name: isChangingConfigurations Like this Just in case, you can't put a getter setter in the User object What's wrong?