RFR(s): 8204243: remove Thread.destroy() and Thread.stop(Throwable)

[Stuart Marks]

On 6/6/18 10:58 AM, serguei.spitsyn at oracle.com wrote:
> But the fix below is not clear to me:
>
> http://cr.openjdk.java.net/~smarks/reviews/8204243/webrev.1/src/hotspot/share/prims/jvmti.xml.udiff.html
>       <function id="StopThread" num="7">
>         <synopsis>Stop Thread</synopsis>
>         <description>
> - Send the specified asynchronous exception to the specified thread
> - (similar to <code>java.lang.Thread.stop</code>).
> + Send the specified asynchronous exception to the specified thread.
>           Normally, this function is used to kill the specified thread with an
> - instance of the exception <code>ThreadDeath</code>.
> + instance of the exception <code>ThreadDeath</code>, similar to
> + <code>java.lang.Thread.stop</code>.
>         </description>
> A reference to the java.lang.Thread.stop has been removed in one place and 
> added in another.
> I thought, we wanted to get rid of these references in the spec.
> Do I miss anything? Could you, explain this a little bit?
Sure. The current state (through JDK 10) is that there two APIs:

     1. Thread.stop(Throwable)
     2. Thread.stop() // no-arg

They are both deprecated, but only (1) is deprecated for removal, and it's the 
one being removed by this changeset. Method (2) will remain in the platform for 
the forseeable future.

Method (1) causes the target thread asynchronously to throw the argument, which 
can be an instance of any subtype of Throwable. Method (2) causes the target 
thread to throw ThreadDeath (a subtype of Error) asynchronously.

The wording in the JVMTI doc isn't terribly explicit. The original wording 
actually means "similar to Thread.stop(Throwable)" that is method (1). My 
rewording places the mention of Thread.stop into the context of throwing 
ThreadDeath, implying method (2). Since that will be the only Thread.stop method 
remaining, there's no ambiguity. So yes, the wording change looks odd, but there 
is a subtle shift in the meaning, and I think the meaning is clear after (1) has 
been removed.

But I can remove the "similar to Thread.stop" bit if you prefer.

s'marks
>
> Thanks,
> Serguei
>
> On 6/5/18 17:05, Stuart Marks wrote:
>> [adding serviceability-dev]
>>
>> Hi serviceability folks,
>>
>> I'm in the process of removing Thread.destroy() and Thread.stop(Throwable) 
>> from the Java SE API. Alan and David have pointed out that there are some 
>> cross-references to Thread.stop(Throwable) in the JDWP and JVMTI specs, as 
>> well as in the JDI ThreadReference API. I've adjusted the relevant files.
>>
>> See please review this updated webrev:
>>
>> http://cr.openjdk.java.net/~smarks/reviews/8204243/webrev.1/
>>
>> For context, please see the full review thread on core-libs-dev:
>>
>> http://mail.openjdk.java.net/pipermail/core-libs-dev/2018-June/053536.html
>>
>>
>>
>> On 6/4/18 11:11 PM, Alan Bateman wrote:
>>> The source file that is used to generate the JDWP protocol code and the spec 
>>> is in make/data/jdwp/jdwp.spec. The JVM TI spec is at 
>>> src/hotspot/share/prims/jvmti.xml. It should be okay to skip those for this 
>>> change-set, assuming it is followed up quickly with another change-set to 
>>> update those specs.
>>
>> OK. I took a look at those other files and they seem simple enough to update 
>> as part of this changeset. If there aren't any objections from anyone, might 
>> as well get this all done at once.
>>
>> Thanks,
>>
>> s'marks
>