![Arthas](https://arthas.aliyun.com/doc/_images/arthas.png)

`Arthas` is a Java diagnostic tool open-sourced by Alibaba middleware team. Arthas helps developers in trouble-shooting issues in production environment for Java based applications without modifying code or restarting servers.

This tutorial show how to debug `ognl` express in Arths.

* Github: https://github.com/alibaba/arthas
* Docs: https://arthas.aliyun.com/doc/en