public class BrokenEncapsulation {
    static class Account {
        private double balance = 100;
    }
    public static void main(String[] args) {
        Account a = new Account();
        a.balance = 1_000_000;   // legal here: a nested class shares its outer class's privacy
        System.out.println(a.balance);
    }
}
class Outsider {
    void cheat() {
        BrokenEncapsulation.Account a = new BrokenEncapsulation.Account();
        a.balance = 1_000_000;
    }
}