RFR of JDK-8134599: TEST_BUG: java/rmi/transport/closeServerSocket/CloseServerSocket.java fails intermittently with Address already in use

[Weijun Wang]

> On Oct 15, 2019, at 5:44 PM, Hamlin Li <huaming.li at oracle.com> wrote:
> 
> 
> On 2019/10/15 2:44 PM, Weijun Wang wrote:
>> I am OK with the change that makes this test more robust.
> Thanks Max.
>> 
>> However, I am not an expert in RMI and don't know why the port cannot be released. If verifyPortFree(PORT) on line 60 can always succeed right after TestLibrary.getUnusedRandomPort() tries to create a ServerSocket at PORT and close it, this means the OS underneath spends no time in freeing the port.
> 
> No, the port is not freed here, it's only freed by unexportObject.

I meant the auto close inside getUnusedRandomPort().

> 
> But the original code is a little bit faulty at verifyPortInUse, it should be as below, I have also updated the webrev in place: http://cr.openjdk.java.net/~mli/8134599/webrev.01/
> 
> @@ -101,6 +112,7 @@
>      private static void verifyPortInUse(int port) throws IOException {
>          try {
>              verifyPortFree(port);
> +            throw new RuntimeException("port is not in use: " + port);
> 
>> Is UnicastRemoteObject.unexportObject() also doing something similar? I see that the ServerSocket inside is closed on TCPTransport.java:280. Is it reliably called?
> 
> In my understanding, it's not a sync operation, it's async, that means when unexportObject returns, it just triggers the port release, does not mean it already released the port.

Ah.... 

> 
>> 
>> Even after this bug is resolved, I'd suggest add some logging and rerun this test unchanged multiple times to see what really happened.
> 
> Unfortunately, most of time this kind of issue is not easy to reproduce by running it multiple times. In my point of view, current logging is sufficient for diagnosing.

I see some logging calls inside source code. Maybe you can set a logging config file to let it show more?

--Max

> 
> Thank you
> 
> -Hamlin
> 
>> 
>> --Max
>> 
>> 
>>> On Oct 15, 2019, at 11:04 AM, Hamlin Li <huaming.li at oracle.com> wrote:
>>> 
>>> Thanks for reviewing, I updated change at: http://cr.openjdk.java.net/~mli/8134599/webrev.01/
>>> 
>>> it does not increase minimum time time and consider timeout factor at the same time.
>>> 
>>> Thank you
>>> 
>>> -Hamlin
>>>