zend framework 2 doctrine 2 - class xxx sub class of yyy is not a valid entity or mapped super class

Question

I'm using "doctrine/orm": "2.4." and "doctrine/doctrine-orm-module": "0.8.".

Please check below json.

      {
       "name": "zendframework/skeleton-application",
       "description": "Skeleton Application for ZF2",
       "license": "BSD-3-Clause",
       "keywords": [
             "framework",
             "zf2"
        ],
        "homepage": "http://framework.zend.com/",
        "require": {
            "php": ">=5.3.0",
            "zendframework/zendframework": "2.3.*",
            "doctrine/doctrine-orm-module": "0.8.*",
            "doctrine/orm": "2.4.*"
        } ,"autoload": {
            "psr-0": {"StripLib\\": "vendor/stripe/lib/"}
        }
  }

My entity class file as below.

  <?php

    namespace Application\Entity;

     use Doctrine\ORM\Mapping as ORM;
     use Doctrine\ORM\QueryBuilder;
     use Zend\Crypt\Password\Bcrypt;

     /**
      * User
      *
      * @ORM\Table(name="user")
      * @ORM\Entity
      */
    class User extends Entity {

    public static $table;

    public function __construct() {
         self::$table = $this->getTableName();
    }

The whole project run smoothly before encoding.

But when I encode whole project files by ZendGuard tool and run project it gives me error like below:

    **Class "Application\Entity\User" sub class of "Application\Entity\Entity" is not a valid entity or mapped super class.**