Class DemoHelloworldControllerPostindexInterceptor does not exist

I am trying to get data from database table, my code of index.php

<?php
namespace DemoHelloworldControllerPost;
class Index extends MagentoFrameworkAppActionAction
{
    protected $_postFactory;
    public function __construct(
        MagentoFrameworkAppActionContext $context,
        MagentoFrameworkViewResultPageFactory $pageFactory,
        PixelproHelloworldModelPostFactory $postFactory
        )
    {
        $this->_pageFactory = $pageFactory;
        $this->_postFactory = $postFactory;
        return parent::__construct($context);
    }
    public function execute()
    {
        
        $post = $this->_postFactory->create();
        $collection = $post->getCollection();
        foreach($collection as $item){
            echo "<pre>";
            print_r($item->getData());
            echo "</pre>";
        }
        
        
    }
}

I tried to run these commands but error still appears

php bin/magento setup:upgrade
php bin/magento setup:static-content:deploy -f
php bin/magento cache:flush

the error :

1 exception(s):
Exception #0 (ReflectionException): Class DemoHelloworldControllerPostindexInterceptor does not exist
Exception #0 (ReflectionException): Class DemoHelloworldControllerPostindexInterceptor does not exist#1 MagentoFrameworkCodeReaderClassReader->getConstructor() called at [vendor/magento/framework/ObjectManager/Definition/Runtime.php:54]