Final Class- A class that can’t be extended and inherited further is known as Final Class. This class is declared with the keyword final and should be declared.

Final Method- Methods in the final class are implicitly final and if a user uses the final keyword that means methods can’t be overridden by subclasses.

BY Best Interview Question ON 03 Nov 2021

Example

class childClassname extends parentClassname {
    protected $numPages;

    public function __construct($author, $pages) {
        $this->_author = $author;
        $this->numPages = $pages;
    }

    final public function PageCount() {
        return $this->numPages;
    }
}