So to be precise, my APP is a jetty based application, it includes jetty
jars and related jetty configuration files.
When this application is deployed on ubuntu (Non-CF) environment, we can
get expect status message we customized.
But when deploying to CF, the customized message is always changed to the
standard status message.
Since all the jetty jars and configuration files are included in our APP
already, so there should no difference in jetty part.

That's why we suspect the problem is in CF related things, but really got
no clue where is it.
We do have some code related to this behavior, and since it's standard
servlet behavior, so I think we should supports it?
http://www.java2s.com/Code/JavaAPI/javax.servlet.http/HttpServletResponsesendErrorintarg0Stringarg1.htm


Attached is one simple jetty based application, when I run it locally I can
get my customized message.

wget http://localhost:8080/hello
--2016-05-03 18:15:22-- http://localhost:8080/hello
Resolving localhost... 127.0.0.1, ::1
Connecting to localhost|127.0.0.1|:8080... connected.
HTTP request sent, awaiting response... 403 my customized 413 error message
2016-05-03 18:15:22 ERROR 403: my customized 413 error message.

When pushing to CF, I still got the standard message.
HTTP request sent, awaiting response... 403 Forbidden
2016-05-03 18:18:46 ERROR 403: Forbidden.

Thanks,
Stanley