In the javadoc of class DefaultMQProducer, the IDE prompts a lot of warning messages.

[XiaoyiPeng]

BUG REPORT

1. Please describe the issue you observed:

   In the javadoc of class DefaultMQProducer, the IDE prompts a lot of warning messages, it is better to fix it.

   For example, see the figure below.

   

2. Please tell us about your environment:
   OS: Windows10
   branch: develop