• I have searched the issues of this repository and believe that this is not a duplicate.
• I have checked the FAQ of this repository and believe that this is not a duplicate.

Environment

• Dubbo version: 2.6.2
• Operating System version: mac os
• Java version: 1.8

Steps to reproduce this issue

com.alibaba.dubbo.common.Constants#DEFAULT_SERVER_SHUTDOWN_TIMEOUT，
I think this number is too big，2~3 second is enough。

Expected Result

make a small default value 。

Actual Result

What actually happens?

If there is an exception, please attach the exception trace: