What is Information Hiding in OOP?

Answer 1

There is no such concept as information hiding in OOP. While many programmers incorrectly believe private and protected member variables are hidden in a class, these access specifiers do nothing more than limit access to those variables, they do not actually hide anything. Information hiding is actually a function of binary executables and libraries, not OOP, because information can be obfuscated by procedural machine code far more easily than with structured source code.

When referring to OOP, we use the term abstraction rather than information hiding. Abstraction relates to the way in which it is not necessary to know the underlying storage mechanism of a class, nor its implementation details, in order to make use of a class. This allows the class designer to alter the class design specification without affecting the existing consumers, provided the existing abstract interface remains unaltered. In other words, it reduces maintenance by localising changes within the class, rather than affecting code outside of the class as would occur in a non-OOP environment. It is the interface which provides the abstraction, but it does not physically hide anything. That is, while it is not necessary to know the underlying storage or implementation details of the class, there is absolutely nothing to prevent you from looking at those details, even if those details are obfuscated within a binary library (just because something is hidden doesn't mean it can't be found with a bit of effort).