hotspot messages about the future?

Kelly O'Hair kelly.ohair at
Fri Oct 8 17:21:43 PDT 2010

There is  a long list of CRs related to hotspot stdout and stderr  
(start with 4837953).

The issue I remember is that if I write a java app that uses stdout  
and stderr in it's logic,
and hotspot or the jdk also dumps text to stdout and stderr, it makes  
the java app's stdout/stderr
pretty worthless.

The java app needs to own stdout and stderr, in my opinion, or at a  
minimum it needs to own stdout.

I always thought the VM was supposed to be somewhat invisible, the OZ  
guy behind the curtain, unseen
unless something REALLY serious happens.


On Oct 8, 2010, at 4:06 PM, John Pampuch wrote:

> My recollection is that we choose not to insert messages like this.   
> From my perspective, the output could get really noisy, and spurious  
> output in a release like that *could* affect a shell script, so it  
> could get annoying.
> Not sure if I'm completely right on the policy, and even if I am, it  
> probably isn't written down anywhere.  At very least, I don't recall  
> us doing it before (not that I'm in a habit of checking.)
> -John
> On 10/8/10 3:54 PM, David Holmes wrote:
>> Kelly O'Hair said the following on 10/09/10 05:21:
>>> When did the  hotspot -XX options start spitting out messages like  
>>> this?
>> I can't tell exactly, but this was there when HS moved to Mercurial.
>> I think it is done whenever an option has become obsolete, or is  
>> not applicable/appropriate for the given usage.
>> David
>>> svc6<1263> java -XX:+CMSClassUnloadingEnabled -XX: 
>>> +CMSPermGenSweepingEnabled -version
>>> Please use CMSClassUnloadingEnabled in place of  
>>> CMSPermGenSweepingEnabled in the future
>>> java version "1.6.0_10"
>>> Java(TM) SE Runtime Environment (build 1.6.0_10-b33)
>>> Java HotSpot(TM) Server VM (build 11.0-b15, mixed mode)
>>> I always thought silence was golden?
>>> -kto

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