Null object when setting the value

I make a request, get a list and make a weather forecast out of it. On request, it comes to a variable, but when setting the value, I get an error. Help find the problem.

The problem is in the line - String tempWithDegree = weatherDays.get(position).getTempWithDegree();
holder.textViewTemp.setText(tempWithDegree);

Debug shows that the variable gets value

Class WeatherDay:

public class WeatherDay {

public  class WeatherTemp {
    Double temp;
    Double temp_min;
    Double temp_max;
}

public  class WeatherDescription {
    String icon;
}

@SerializedName("main")
private WeatherTemp temp;

@SerializedName("weather")
private List<WeatherDescription> descriptions;

@SerializedName("name")
private String city;

@SerializedName("dt")
private long timestamp;

public WeatherDay(WeatherTemp temp, List<WeatherDescription> descriptions) {
    this.temp = temp;
    this.descriptions = descriptions;
}

public Calendar getDate() {
    Calendar date = Calendar.getInstance();
    date.setTimeInMillis(timestamp * 1000);
    return date;
}

public String getTemp() { return String.valueOf(temp.temp); }

public String getTempMin() { return String.valueOf(temp.temp_min); }

public String getTempMax() { return String.valueOf(temp.temp_max); }

public String getTempInteger() { return String.valueOf(temp.temp.intValue()); }

public String getTempWithDegree() { return (temp.temp.intValue()) + "\u00B0"; }

public String getCity() { return city; }

public String getIcon() { return descriptions.get(0).icon; }

public String getIconUrl() {
    return "http://openweathermap.org/img/w/" + descriptions.get(0).icon + ".png";
}

Class Forecast:

  @SerializedName("list")
private List<WeatherDay> items;

public WeatherForecast(List<WeatherDay> items) {
    this.items = items;
}

public List<WeatherDay> getItems() {
    return items;
}

Error:

 java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference

My Adapter Class:

public class ForecastAdapter extends RecyclerView.Adapter<ForecastAdapter.ForecastHolder>{
private List<WeatherDay> weatherDays = new ArrayList<>();



@NonNull
@Override
public ForecastHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
    View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.weather_item, parent, false);
    return new ForecastHolder(view);
}

@Override
public void onBindViewHolder(@NonNull ForecastHolder holder, int position) {
    SimpleDateFormat formatDayOfWeek = new SimpleDateFormat("E");
    if (weatherDays.get(position).getDate().get(Calendar.HOUR_OF_DAY) == 15) {
        String dayOfWeek = formatDayOfWeek.format(weatherDays.get(position).getDate().getTime());
        holder.textViewDay.setText(dayOfWeek);

    //    String tempWithDegree = weatherDays.get(position).getTempWithDegree();
   //     holder.textViewTemp.setText(tempWithDegree);
        Picasso.get().load(weatherDays.get(position).getIconUrl()).into(holder.imageView);
    }

}

@Override
public int getItemCount() {
    return weatherDays.size();
}

public void setWeatherDays(List<WeatherDay> days) {
    weatherDays.addAll(days);
    notifyDataSetChanged();
}

public void clearForecasts() {
    weatherDays.clear();
    notifyDataSetChanged();
}


public class ForecastHolder extends RecyclerView.ViewHolder {
    private TextView textViewTemp;
    private TextView textViewDay;
    private ImageView imageView;

    public ForecastHolder(@NonNull View itemView) {
        super(itemView);
        textViewTemp = itemView.findViewById(R.id.txtViewTemp);
        imageView = itemView.findViewById(R.id.imageView);
        textViewDay = itemView.findViewById(R.id.txtViewDay);
    }
}

}

Thank for u help!

The exception was thrown because textViewTemp is null in holder.textViewTemp.setText(...).

You are not setting a value for textViewTemp in the view holder object in the onCreateViewHolder method. If it looks like you are, consider the possibility that looking up the view failed. Perhaps the layout you are using does not have a view with the ID you are using.

The problem isn't about value. It's about textViewTemp. You haven't initialized it. If you share your adapter class, we can help you