How to restrict the accessibility of a class to specific class(es)

Question

How can I restrict accessibility of a class (instantiating or using) to a specific class or a set of classes. For example, I have a class 'CreditCard'. I want to limit its accessibility to a specific class 'CreditCardManager'. i.e., anyone could only create or use objects of 'CreditCard' class from 'CreditCardManager' class only.
This may look like 'friend' functionality in c++. But it is not. The private members should not be accessed from the manager class.

Answer 1

Define a CreditCard interface:
public interface CreditCard {
}Put the implementation inside CreditCardManager:
public class CreditCardManager {
    private /* static (?) */ class CreditCardImpl implements CreditCard {
    public CreditCard newCreditCard(...) {
        CreditCard  cc = new CreditCardImpl();
        return cc;
}Since you are going on about it, I assume CreditCard is a key concept in your app, so there are probably other reasons to make it an interface too. For example, so that youi can mock it in unit tests.