Package modernfeatures.java17

Class SealedClassesDemo

java.lang.Object

modernfeatures.java17.SealedClassesDemo

public class SealedClassesDemo
extends Object

Demonstrates Java 17+ sealed classes, which restrict which classes can extend a superclass.

This example shows:

• How to declare a sealed class (Shape) and specify the permitted subclasses.
• Usage of final and non-sealed subclasses to control the inheritance hierarchy.
• How pattern matching with switch expressions can safely handle all permitted subclasses, providing exhaustive type checking at compile time.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static final class	SealedClassesDemo.Circle
static class	SealedClassesDemo.Rectangle
static class	SealedClassesDemo.Shape
static final class	SealedClassesDemo.Square

Constructor Summary

Constructors

Constructor	Description
SealedClassesDemo()

Method Summary

Modifier and Type	Method	Description
static void	main(String[] args)	Main entry point: creates instances of the permitted Shape subclasses, iterates through them, and uses a pattern-matching switch expression to print descriptive information about each shape.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

SealedClassesDemo

public SealedClassesDemo()

Method Details

main

public static void main(String[] args)

Main entry point: creates instances of the permitted Shape subclasses, iterates through them, and uses a pattern-matching switch expression to print descriptive information about each shape.