PHP 7 Anonymous Classes

anonymousClass.php

<?php
abstract class AbstractClass { // Could be an interface
    
    public function concentreMethod()
    {
        echo('I am a concrete method which will not be overwritten');
    }

    public function otherConcentreMethod()
    {
        echo('I am a concrete method which will not be overwritten');
    }

    abstract public function abstractMethod();
}

$newObject = new class () extends AbstractClass {
    public function otherConcentreMethod() // Overriding a concrete method
    {
        echo('I am a concrete method which is being overwritten');
    }

    public function abstractMethod()
    {
        echo('In the concrete anonymous class, I have an implementation'); 
    }
}
$this->assertInstanceOf(
  AbstractClass::class,
  $newObject
); // $newObject is an instance of the AbstractClass, although I have not created any named concrete class.