Ошибка: Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException­: 20

public class Pupil {
    public String last_name, first_name, patronymic; // ФИО
    public String gender; // пол
    public String nationality; // национальность
    public double height, weight; // рост, вес
    public int dd, mm, yyyy;// дата рождения
    public String phone; // Телефон
    public int index;// адрес
    public String country, region, district, city, street, house, apartment;
    public String school;// школа
    public int grade;// класс
    
    public Pupil(){}
    public Pupil(String _l_name, String _f_name, String _patr,
            String _gen, String _nat, double _height, double _weight,
            int _dd, int _mm, int _yyyy, String _phone,
            int _ind, String _country, String _region, String _district,
            String _city, String _street, String _house, String _apartment,
            String _sch, int _grade){
        this.last_name = _l_name;
        this.first_name = _f_name;
        this.patronymic = _patr;
        this.gender = _gen;
        this.nationality = _nat;
        this.height = _height;
        this.weight = _weight;
        this.dd = _dd;
        this.mm = _mm;
        this.yyyy = _yyyy;
        this.phone = _phone;
        this.index = _ind;
        this.country = _country;
        this.region = _region;
        this.district = _district;
        this.city = _city;
        this.street = _street;
        this.house = _house;
        this.apartment = _apartment;
        this.school = _sch;
        this.grade = _grade;
    }
    
    public String   getLastN(){ return this.last_name; }
    public void     setLastN(String _l_name){ this.last_name = _l_name; }
    
    public String   getFirstN(){ return this.first_name; }
    public void     setFirstN(String _f_name){ this.first_name = _f_name; }
    
    public String   getPat(){ return this.patronymic; }
    public void     setPat(String _patr){ this.patronymic = _patr;}
    
    public String   getGen(){ return this.gender; }
    public void     setGen(String _gen){ this.gender = _gen;}
    
    public String   getNat(){ return this.nationality; }
    public void     setNat(String _nat){this.nationality = _nat;}
    
    public double   getHeight(){ return this.height; }
    public void     setHeight(double _height){ this.height = _height;}
    
    public double   getWeight(){ return this.weight; }
    public void     setWeight(double _weight){ this.weight = _weight;}
    
    public int  getDd(){ return this.dd; }
    public void     setDd(int _dd){this.dd = _dd;}
    
    public int  getMm(){ return this.mm; }
    public void     setMm(int _mm){this.mm = _mm;}
    
    public int  getYyyy(){ return this.yyyy; }
    public void     setYyyy(int _yyyy){this.yyyy = _yyyy;}
    
    public String   getPhone(){ return this.phone; }
    public void     setPhone(String _phone){this.phone = _phone;}
    
    public int  getIndex(){ return this.index; }
    public void     setIndex(int _ind){this.index=_ind;}
    
    public String   getCountry(){ return this.country; }
    public void     setCountry(String _country){this.country=_country;}
    
    public String   getRegion(){ return this.region; }
    public void     setRegion(String _region){this.region = _region;}
    
    public String   getDistrict(){ return this.district; }
    public void     setDistrict(String _district){this.district = _district;}
    
    public String   getCity(){ return this.city; }
    public void     setCity(String _city){this.city = _city;}
    
    public String   getStreet(){ return this.street; }
    public void     setStreet(String _street){this.street = _street;}
    
    public String   getHouse(){ return this.house; }
    public void     setHouse(String _house){this.house = _house;}
    
    public String   getApartment(){ return this.apartment; }
    public void     setApartment(String _apartment){this.apartment = _apartment;}
    
    public String   getSchool(){ return this.school; }
    public void     setSchool(String _sch){this.school = _sch;}
 
    public int  getGrade(){ return this.grade; }
    public void     setGrade(int _grade){this.grade = _grade;}
    
    @Override
    public String toString(){
        return "Pupil: name: " + last_name + " " + first_name + " " + patronymic
        + "\n\t gender: " + gender + " nationality: " + nationality
        + "\n\t height: " + height + " weight: " + weight 
                + " birthdate: " + dd + "-" + mm + "-" + yyyy
                + "\n\t phone: " + phone + " index: " + index 
                + "\n\t address: " + country + ", " + region + ", " + district 
                + ", " + city + ", " + street + ", " + house + ", " + apartment
        + "\n\t school: " + school + " grade: " + grade;
    }
    
}