[9]RFR JDK-8160029: Security-libs tests need to avoid using jdk.testlibrary.Utils.getFreePort()

[John Jiang]

Hi Max,

On 2016/7/9 18:04, Wang Weijun wrote:
> I am not sure. If in the first round a free port is chosen for UDP but it's not available for TCP, how can we avoid the same port being chosen again in the 2nd round? The DatagramSocket object is closed in the catch block and the port number is reclaimed by the OS. Will the OS reuse it immediately in the 2nd round?
I tested the case with the below codes on Windows and Linux,

for (int i = 0; i < 100; i++) {
     try (ServerSocket ss = new ServerSocket(0)) {
         int port = ss.getLocalPort();
         System.out.println(port);
         try (DatagramSocket us = new DatagramSocket(port,
                 InetAddress.getByName("127.0.0.1"))) {
         }
     }

     Thread.sleep(500);
}

The outputs like the followings:
Windows 7:
     57632
     57633
     57634
     57635
     57636
     57637
     57638
     57639
     57640
     57641
     57642
     57643
     57644
     57645
     57646
     57647
     57648
     57649
     57650
     57651
    ...

Ubuntu 15.10:
     45916
     44807
     33578
     40244
     46033
     38966
     34431
     46026
     40069
     39013
     39496
     37745
     36749
     43594
     45667
     46410
     36762
     38565
     35074
     34843
     ...

With the results, the previous port is not reused by the subsequent 
round immediately.

Best regards,
John Jiang
> --Max
>
>> On Jul 9, 2016, at 3:18 PM, John Jiang<sha.jiang at oracle.com>  wrote:
>>
>> Hi Max,
>>
>> On 2016/7/8 16:19, Wang Weijun wrote:
>>> The reason a loop is needed here is that both the TCT and UDP servers must listen on the same port number. With your fix, the TCP server finds a free port, but I doubt if it's free for the UDP server.
>> Yes, it's possible that the port still be occupied by another DatagramSocket.
>> Please review the updated webrev:http://cr.openjdk.java.net/~jjiang/8160029/webrev.01
>>
>> Best regards,
>> John Jiang
>>
>>> --Max
>>>
>>>
>>>> On Jul 8, 2016, at 2:35 PM, John Jiang<sha.jiang at oracle.com>  wrote:
>>>>
>>>> Hi,
>>>> Would you like to review this patch for removing unnecessary usages on jdk.testlibrary.Utils.getFreePort() from security-libs tests?
>>>> In OpenJDK, I find only sun/security/krb5/auto/KDC.java should be modified for this issue.
>>>> If I miss something, please let me know.
>>>>
>>>> Issue:https://bugs.openjdk.java.net/browse/JDK-8160029
>>>> Webrev:http://cr.openjdk.java.net/~jjiang/8160029/webrev.00
>>>>
>>>> Thanks!
>>>>
>>>> John Jiang
>>>>
>>>>

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