What is the meaning of final class and final method in PHP?

The final keyword is used to stop inheritance. If a class is marked final, no other class can extend it. If a method is marked final, child classes can not override it.

<?php
class Base {
    final public function show() {
        echo "This method can not be changed";
    }
}

class Child extends Base {
    // Writing show() here would give a fatal error
}

$c = new Child();
$c->show();
?>

Output:

A final class is written like this:

<?php
final class Util {
    public static function version() {
        return "1.0";
    }
}

// class Other extends Util {}  // Fatal error: a final class can not be extended
?>

When to use it: when a class or method must not be changed, for example a security check or a core logic. Note that properties can not be final, but from PHP 8.1 you can use readonly for properties that must not change after setting.

• Previous Interview Question
• Next Interview Question

---

Tutorials
No Content Found.

Exercises & Assignments
No Content Found.

Interview Questions & Answers
No Content Found.