java.net.Socket should report the attempted address and port

[James Roper]

This would be especially useful in asynchronous applications - since in
those cases the exception rarely maps back to a place in user code that
would indicate what is being connected to. As someone who has spent a lot
of time supporting developers who use asynchronous libraries and post
exceptions of this nature (supporting both in open source, eg on stack
overflow, as well as providing commercial support), where I don't have
access to their code base so I can't do the necessary investigations
directly myself, having the attempted address and port in the error message
would save a lot of time, and probably even prevent a lot of people from
requiring support in the first place.

On 22 April 2018 at 20:59, Péter Gergely Horváth <
peter.gergely.horvath at gmail.com> wrote:

> Hi All,
>
> I am wondering if it would be possible to make a minor improvement to the
> way *java.net.Socket* reports connectivity errors and incorporate the
> attempted address, port and the timeout used into the exception message.
>
> The current implementation emits a generic error message, which is not
> that helpful when one is operating a _large_ application. (Consider e.g.
> Big Data or complex legacy systems written by someone else).
>
> java.net.ConnectException: Connection refused (Connection refused)
> at java.net.PlainSocketImpl.socketConnect(Native Method)
> at java.net.AbstractPlainSocketImpl.doConnect(
> AbstractPlainSocketImpl.java:350)
> at java.net.AbstractPlainSocketImpl.connectToAddress(
> AbstractPlainSocketImpl.java:206)
> at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:
> 188)
> at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
> at java.net.Socket.connect(Socket.java:589)
> at java.net.Socket.connect(Socket.java:538)
> at java.net.Socket.<init>(Socket.java:434)
> at java.net.Socket.<init>(Socket.java:211)
> at Sample.main(Sample.java:9)
>
>
> I have looked into the JDK code base and implemented a patch that reports
> the address, port and timeout used in the error message without touching
> any native parts (see attached patch file). I have tested this (created my
> own build of the JDK and run a sample application against it) and it seems
> to work properly.
>
> Would it be possible to incorporate this change into the official JDK code
> base? I do believe it would help a lot of people out there.
>
> Based on my understanding, once I have signed the OCA, I should simply
> write an email to the group and request a sponsor to pick up this issue.
> Could someone help me with this?
>
> Thank you,
> Peter
>
>
>
>
>
>
>
>


-- 
*James Roper*
*Senior Octonaut*

Lightbend <https://www.lightbend.com/> – Build reactive apps!
Twitter: @jroper <https://twitter.com/jroper>
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