8191846: jstat prints debug message when debugging is disabled

[Erik Helin]

Hi Per,

On 11/24/2017 09:01 AM, Per Liden wrote:
> Hi,
> 
> jstat is designed to handle the case where a perf counter doesn't exits. 
> In the output jstat will then print a "-" instead of the perf counter 
> value to indicate that the counter doesn't exist. However, jstat also 
> prints an unnecessary message, which clobbers the output. This message 
> might still be useful for debugging, but should only be printed when 
> jstat is running with debug messages enabled 
> (-J-DExpressionResolver.debug=true).
> 
> Webrev: http://cr.openjdk.java.net/~pliden/8191846/webrev.0/

I have limited experience of jstat (I have only contributed two patches 
to jstat), but this looks good as far as I can see.

Thanks,
Erik

> Bug: https://bugs.openjdk.java.net/browse/JDK-8191846
> Testing: hs-tier1, hs-tier2
> 
> /Per