RFR: JDK-8154331: main thread should be treated as JNI-attached thread.

[David Holmes]

Hi Yasumasa,

On 15/04/2016 11:23 PM, Yasumasa Suenaga wrote:
> Hi all,
> 
> In discussion about JDK-8152690 [1], we were found a bug.
> Java main thread which is started by Java launcher is not treated as JNI-attached thread.
> 
> I uploaded a webrev.
> Could you review it?
> 
>    http://cr.openjdk.java.net/~ysuenaga/JDK-8154331/webrev.00/
> 
> I cannot access JPRT.
> So I need a sponsor.

As I just wrote in the bug report:

I think it was an oversight that when the OSX port brought this code in,
the main thread was not marked as being a JNI-attached thread - as
suggested by this comment:

JavaThread(bool is_attaching_via_jni = false); // for main thread and
JNI attached threads

However because of this oversight a call to Thread.setName from the main
thread would** cause the native thread name to be set (normally we don't
modify JNI-attached threads). Correcting this behaviour could be seen as
a regression because there would no be no way to set the native name of
the main thread.

Given that we don't actually gain anything by "fixing" this I'm inclined
to simply leave it as-is.

** I haven't actually verified this as I don't have access to a system I
can check it on right now. But based on code inspection this appears to
be the case.

Thanks,
David

> 
> Thanks,
> 
> Yasumasa
> 
> 
> [1] http://mail.openjdk.java.net/pipermail/core-libs-dev/2016-April/040251.html
>