Objective: Learn Generics.

What are generics?
Allow type (both regular and user defined) to be a parameter to methods, classes,
and interfaces. These type parameters provide a way to re-use the same code with
different inputs.


Why do we use generics?
- Generics allow compile-time type safety check, makes it easier to debug code.
- Using generics can eliminate the need of casting.
- Enable implementing generic algorithms that work on collections of different
  types, and are easier to customize.