ENUMERATIONS AND NESTED CLASSES

Enumeration (enum)

A data type that contains a fixed set of constants

Enum constants

The specific values defined inside an enum that are the only allowed values

Type-safe

A feature where only valid values are allowed preventing invalid data at compile time

Enum declaration

The process of defining an enum using the enum keyword followed by constants

Enum variable

A variable declared using an enum type that can only store its defined constants

Compile-time error

An error detected during compilation when invalid enum values are used

Runtime error

An error that occurs during program execution

toString()

Returns the name of the enum constant as a string

ordinal()

Returns the position of the enum constant starting from 0

equals()

Compares two enum constants and returns true if they are the same

compareTo()

Compares the order of enum constants and returns a positive negative or zero value

valueOf()

Converts a string into its corresponding enum constant

values()

Returns an array containing all enum constants

Enhanced for loop

A loop used to iterate through all enum values using values()

Switch with enum

Using enum constants in a switch statement for cleaner and safer conditional logic

Comparison operators with enums

Using operators like == instead of compareTo() for direct comparison

Nested class

A class defined inside another class

Top-level class

The outer class that contains the nested class

Inner class

A non-static nested class that requires an instance of the outer class

Static member class

A nested class that can access only static members of the outer class

Local class

A class defined inside a method

Anonymous class

A class without a name used for one-time implementations

Private inner class

An inner class that is only accessible within its outer class

Encapsulation (nested classes)

Keeping related data and behavior together while hiding implementation details

Outer class access

The outer class can access members of its inner class

Inner class access

The inner class can access all members even private of the outer class

Code organization

Structuring code to make it easier to understand and maintain using nested classes

Tightly coupled classes

Classes that are closely related and often used together making nesting useful

Reusability limitation (inner class)

Inner classes are typically not reusable outside their outer class