ip-ch05-example-07.java

class ExchangeRate {
    private int CountryCode;
    
    public void b() {
        Info info = new Info();
        int d = info.day;
        int m = info.month;
        int y = info.year;
    }

    public class Info {
        public int day;
        /*package*/ int month;
        private int year;

        public Info() {}

        public void setDay(int day) {
            this.day = day;
        }

        public void a() {
            int code = CountryCode;
        }

    }
}

public class InnerClassEx {
    public static void main(String[] args) {
        // possible
        ExchangeRateEx.Info info = new ExchangeRateEx().new Info();
        info.setDay(0);
        System.out.println(info.day);

        // java.lang.NoSuchMethodException: map.ExchangeRate$Info.<init>()
        try {
            ExchangeRateEx.Info.class.getConstructor(new Class[0]);
        } catch (NoSuchMethodException e) {
            e.printStackTrace();
        }
    }
}