title: Nested Classes

A class inside another class is called a __Nested Class__. In other words, as a class has member variables and member

methods it can also have member classes.

Nested classes are divided into two categories: __static__ and __non-static__. Nested classes that are declared static

are called __static nested classes__. Non-static nested classes are called __inner classes__.

You can say inner classes are of 3 types:

* "Regular" Inner classes

* __It is a way of logically grouping classes that are only used in one place__: If a class is useful to only one other

class, then it is logical to embed it in that class and keep the two together. Nesting such "helper classes" makes

their package more streamlined.

* __It increases encapsulation__: Consider two top-level classes, A and B, where B needs access to members of A that

would otherwise be declared private. By hiding class B within class A, A's members can be declared private and B can

access them. In addition, B itself can be hidden from the outside world.

* __It can lead to more readable and maintainable code__: Nesting small classes within top-level classes places the

code closer to where it is used.