Why do I need to transform variable into final array inside @Override[inner class] method?

I'm using following code :

 public void addConditions(){
    final String arriveHourse, departHourse, arriveMinutes, departMinutes;
    TimePickerDialog.OnTimeSetListener departOnTimeSetListener = new TimePickerDialog.OnTimeSetListener() {
        @Override
        public void onTimeSet(TimePicker timePicker, int selectedHours, int selectedMinutes) {

            departHourse = String.valueOf(selectedHours);
            departMinutes = String.valueOf(selectedMinutes);

        }
    };

...
}

Why the IDE asked me to transform departHourse into final array ?

Why this happened, and how i can avoid that ?

Also if i moved variable outside class, it's work like :

String arriveHourse, departHourse, arriveMinutes, departMinutes;

public void addConditions(){

    TimePickerDialog.OnTimeSetListener departOnTimeSetListener = new TimePickerDialog.OnTimeSetListener() {
        @Override
        public void onTimeSet(TimePicker timePicker, int selectedHours, int selectedMinutes) {

            departHourse = String.valueOf(selectedHours);
            departMinutes = String.valueOf(selectedMinutes);

        }
    };

...
}