Firstly what is Polymorphism and why is it so important? Polymorphism is the ability to have a many implementations of a behavior that conform to a single interface. Put in perhaps slightly better, pragmatic terms, you have one implementations of a caller, that can operate on many implementations of a “parameter”, without conditionals, or changing the callers code. For instance the following, pseudo?, Perl 6-ism method handler( $obj ) { $obj.

It is worth noting that none of the following arguments apply to anything using the keyword static which makes things more procedural (or in some cases functional, than Object Oriented. The suggestion in Java is to give the least required permission, but this, in my humble opinion, violates the Open-Closed Principle. Java has four privacy levels. Giving something the least permission required to function is fine in a Security context, privacy in programming however is simply there to discourage developers from doing stupid things.