Protocol version of Attach API

[David Holmes]

On 26/02/2019 4:01 pm, Yasumasa Suenaga wrote:
> Hi all,
> 
> When I attached to VM which is after 8215622 change via jcmd in JDK 8
> on Linux, jcmd hanged.

What command are you trying to execute through jcmd?

Do we support connection to later VMs from earlier JDK tools?

> I checked the status of target VM and jcmd,
> LinuxAttachListener::read_request() on target VM was waiting for
> subsequent argument.
> 
> 8215622 increased number of arguments of Attach API [1].

Isn't that supposed to be a maximum number of arguments? So if less are 
sent it should still work okay?

> Of course it is my mistake, but I think we can increase version number
> (PROTOCOL_VERSION) because Attach API has been updated in 8215622.
> 
> What do you think?

That will just cause it be rejected rather than hang - right?

Thanks,
David
-----

> If it is accepted, I will file it to JBS.
> 
> 
> Thanks,
> 
> Yasumasa
> 
> 
> [1] http://hg.openjdk.java.net/jdk/jdk/rev/e7cf035682e3#l2.1
>