RFR: JDK-8180709: java -javaagent:agent.jar with run-time that does not contain java.instrument prints confusing error

[Chris Plummer]

Yes.

On 12/18/17 1:14 PM, gary.adams at oracle.com wrote:
> I can just the error message.
> What would you like it to say?
>
> "Module java.instrument may be missing"
>
> On 12/18/17 4:09 PM, serguei.spitsyn at oracle.com wrote:
>> Hi Gary,
>>
>> I have the same concern and like Chris's suggestion.
>>
>> The JMX case must be simpler as there is no need to load the agent 
>> library early at startup.
>> So that it is possible to identify the module jdk.management.agent is 
>> absent in the image.
>> I think, it happens in the java.lang.Module.Resolver.
>>
>> The instrument library is loaded early at startup when the Module 
>> system is not
>> up yet, so we don't know if the module java.instrument is present or 
>> not.
>> The instrument library can be not found because of other reasons.
>>
>> Other than that the fix looks okay to me.
>>
>> Thanks,
>> Serguei
>>
>>
>> On 12/18/17 11:39, Chris Plummer wrote:
>>> Hi Gary,
>>>
>>> Overall looks good. There's one minor change you might wanted to 
>>> consider. It's possible the library failed to load for reasons other 
>>> than java.instrument not being included. I see the error output 
>>> already includes the error message from the failed dll_open() call, 
>>> so why not just suggest that it *may* be due to java.instrument 
>>> missing rather than implying that is known to be the reason why.
>>>
>>> thanks,
>>>
>>> Chris
>>>
>>> On 12/18/17 6:38 AM, Gary Adams wrote:
>>>> Here's a simple fix to include additional information when the 
>>>> instrument library is
>>>> missing from the jre and the command line requests -javaagent.
>>>>
>>>>  Issue: https://bugs.openjdk.java.net/browse/JDK-8180709
>>>>  Webrev: http://cr.openjdk.java.net/~gadams/8180709/webrev.00/
>>>>
>>>>
>>>
>>>
>>
>