AddressBook.java

class AddressBook {
    private AddressBookRepository repository;

    public AddressBook(AddressBookRepository repository) {
        this.repository = repository;
    }

    public Address getAddressById(int i) {
        return repository.findById(i);
    }
}

class AddressBookRepository {
    public Address findById(int i) {
        return new Address(i);
    }
}

class Address {
    private int i;

    public Address(int i) {
        this.i = i;
    }
}