Nested Classes

Nested classes are classes defined within another class, allowing for logical grouping of related classes and encapsulation of helper or utility classes. They can be static or non-static (inner classes), with static nested classes behaving like top-level classes and inner classes having access to the enclosing class's members. This concept is commonly used in object-oriented programming languages like Java, C++, and C# to improve code organization and reduce namespace pollution.

Also known as: Inner Classes, Static Nested Classes, Nested Types, Inner Types, Enclosed Classes

Why learn Nested Classes?

Developers should use nested classes when they need to logically group helper classes that are only used by the enclosing class, enhancing encapsulation and readability. For example, in Java, a LinkedList class might define a Node class as a private static nested class to hide implementation details. They are also useful for event handling in GUI frameworks, where inner classes can access outer class fields without exposing them publicly.

Learning Resources

• docs: Oracle Java Tutorials: Nested Classes
• tutorial: GeeksforGeeks: Nested Classes in Java
• docs: Microsoft Learn: Nested Types in C#
• video: YouTube: Inner Classes in Java by Programming with Mosh
• tutorial: Baeldung: A Guide to Inner Classes in Java