What are sealed classes in Java 17?

What are sealed classes in Java 17?

Sealed classes in Java 17 allow you to control which classes can extend or implement them. This helps in maintaining a controlled hierarchy.

How do I define a sealed class?

You define a sealed class using the sealed keyword, followed by the class definition. You also need to specify permitted subclasses.

Can you give me an example of a sealed class?

Sure! Here's a simple example:

public sealed class Shape permits Circle, Square {
    // class body
}

public final class Circle extends Shape {
    // class body
}

public final class Square extends Shape {
    // class body
}

What are the benefits of using sealed classes?

Sealed classes provide better control over class hierarchies, improve maintainability, and enhance type safety.