hotspot messages about the future?

[John Rose]

Absolute silence is a fine ideal.  As long as we are less than ideal, there's also this:
  -XX:+UnlockDiagnosticVMOptions -XX:-DisplayVMOutput

(Seems a bit odd to have to unlock diagnostics to turn them off, but there's where it stands today.)

And conversely:
  -XX:+UnlockDiagnosticVMOptions -XX:+LogVMOutput

-- John

On Oct 8, 2010, at 5:21 PM, Kelly O'Hair wrote:

> 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.
> 
> -kto
> 
> 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 
>>>> 
>