RFR: JDK-8152690: main thread does not have native thread name

[David Holmes]

On 19/04/2016 10:54 PM, Gerard Ziemski wrote:
>
>> On Apr 19, 2016, at 12:04 AM, David Holmes <david.holmes at oracle.com> wrote:
>>
>> On 19/04/2016 9:28 AM, Yasumasa Suenaga wrote:
>>> Hi Gerard,
>>>
>>> 2016/04/19 3:14 "Gerard Ziemski" <gerard.ziemski at oracle.com
>>> <mailto:gerard.ziemski at oracle.com>>:
>>>>
>>>> hi Yasumasa,
>>>>
>>>> Nice work. I have 2 questions:
>>>>
>>>> ========
>>>> File: java.c
>>>>
>>>> #1 Shouldn’t we be checking for “(*env)->ExceptionOccurred(env)”
>>> after every single JNI call? In this example instead of NULL_CHECK,
>>> should we be using CHECK_EXCEPTION_NULL_LEAVE macro?
>>>
>>> It is not critical if we encounter error at JNI function call  because
>>> we cannot set native thread name only.
>>> So I think that we do not need to leave from launcher process.
>>
>> I agree we do not need to abort if an exception occurs (and in fact I don't think an exception is even possible from this code), but we should ensure any pending exception is cleared before any futher JNI calls might be made. Note that NULL_CHECK is already used extensively throughout the launcher code - so if this usage is wrong then it is all wrong! More on this code below ...
>
> Isn’t there a risk that:
>
> (*env)->CallVoidMethod(env, currentThread, setNativeNameID,
> +                           nameString, JNI_TRUE);
>
> will raise an exception?
>
> In the least, shouldn’t we clear any possible pending exceptions at the beginning of “SetNativeThreadName“, as you say, but also at the very end?

I was actually saying at the end, after the call (even though I don't 
think any exceptions are possible - except for "async" exceptions of 
course). We shouldn't be able to get to the call with any exception 
pending as in that case the JNI calls will be returning NULL and we will 
exit - again this pattern is used extensively in the launcher.

David

>
> cheers
>