在PHP内部运行Java时返回空结果

I wrote a java class with name GetRandomKey.class

I run this file with this command:

<?php
    echo shell_exec('java GetRandomKey');
?>

This code is run in local (Windows 10 - 64bit)

But I upload in VPS with Windows server 2016 and 64bit.

It doesn't work and it returns an empty result!

I wrote this code shell_exec('dir') and its return result. but I can't run java command.

I get this Error!

C:\Program Files\Java\jre1.8.0_202\lib\amd64\jvm.cfg