[9] RFR of JDK-8085192: java/rmi/activation/Activatable tests fail intermittently due to "Port already in use"

[Chris Hegarty]

Roger,

I addressed all, or most, of your comments in the following
webrev.

  1) Refactored out the use of sun.nio.ch in the test library,
    so that a reduced number of tests need their @modules tag
    updated. ( @modules support with test library usage it a
    pain )

  2) Use Boolean.getBoolean to retrieve the new property

  3) fix typos and remove stray debugging statements

   http://cr.openjdk.java.net/~chegar/8085192_webrev.03/

> ...
> I'm vaguely not very comfortable with scraping the port number off stdout
> and the inherited channel pieces seem like a lot of moving parts.

Right, I was a little uneasy with this too, to being with, but
it has grown on me ( since it appears stable and reliable in
all my builds and tests ). Also the surface area of the code
change is very small, and the inherit channel mechanism is well
specified and stable.

> Roger
>
> p.s.  Anyother idea
> I assume not all platforms can allow separate processes to open server
> sockets to the same port.
> If so, we would just have the client allocate a port (0), mark it
> non-exclusive and keep it open
> while passing the port number to RMID. Only after RMID is started close
> the allocating socket.

I believe Stuart did look at this in some detail a while back [1], and
it was somewhat dismissed because of the lack of cross platform support
for SO_REUSEPORT. Maybe things have move on, but I don't think so?

The use of inherit channel is somewhat akin to loading an agent into
the target, but more straightforward.

What do others think, that will have to maintain these tests? I don't
want to make them every harder to maintain. Hamlin's approach is still
on the table too.

-Chris.

[1] 
http://mail.openjdk.java.net/pipermail/serviceability-dev/2014-December/016251.html