Question

If I have a java class which is package-private (declared with “class”, not “public class”), there is really no difference if the methods inside are declared public or protected or package-private, right? So which should I use, or when should I use which? I’m a bit confused.

Answer 1

If I have a java class which is package-private (declared with “class”, not “public class”), there is really no difference if the methods inside are declared public or protected or package-private, right?

Well maybe not immediately. But if you then (or in the future) declare a ‘protected’ or ‘public’ class that inherits from the package-private class, then the visibility of the members of the original class do matter.

As @kmccoy points out, declaring the class as final removes the possibility of subclasses.

But this is really only window-dressing. If you then decide that you really need to create subclasses, you simply remove the final … and then you are back in the situation where the choice of access modifiers does matter.

IMO, the bottom line is that you should pick the most appropriate modifiers … even if it is not necessary right now. If nothing else, your choice of modifiers should document your intent as to where the abstraction boundaries lie.