PHP & Java: Is setting property's visibility private and accessing it via getter from derived class overkill?

Question

So what do you think?

My Java lecturer said that properties should always be declared private and there is no reason why it should be done any other way. I immediately started to think inheritance, how it would affect to that.

Answer 1

Do you mean declaring the field to be private? If so, I agree with your lecturer, although "no reason" may be slightly overkill. There are very occasional reasons to use non-private fields - such as in private nested classes.

But yes, in a simple superclass/subclass relationship I would use getters/setters instead of making the field protected. It separates the implementation from the API exposed by the class - even to its subclasses.

Answer 2

Private would prevent classes that extend the original class from accessing it directly. Generally speaking I think that protected is a better way to declare a variable if you expect to extend your original class and want the inheriting class to be able to directly modify that particular class member.