Room101.java

package orwell;

import java.lang.reflect.Field;

public class Room101 {

    public static void main(String[] args) {
        Integer result = 2 + 2;

        System.out.printf("2 + 2 = %d\n", result);

        room101();

        System.out.printf("2 + 2 = %d\n", result);
    }

    private static void room101() {
        try {
            Integer four = 4;
            Field field = four.getClass().getDeclaredField("value");
            field.setAccessible(true);
            field.set(four, 5);

        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }
}