Java double checked locking - Strings

Question

Given that strings contain final field, does it mean in the context of double checked locking it is not necessary to declare them volatile? E.g.

<

Answer 1

For strings you're right. A string which is declared final cannot be differed and therefore you do not need to synchronize when using it.

Thats not true for other Objects. Take this little class for example:

public class BankAccount {
    private int balance = 0;
    public void addMoney(int money) {
        balance+=money;
    }
}

When you've got a final Object of this class it doesn't mean that nobody can change the fields inside the object. You just can't assign something else to the final variable!

Conclusion: When accessing final String you don't need to synchronize, when accessing final Objects you might have to, depending on the Object itself.