7015589: (spec) BufferedWriter.close leaves stream open if close of underlying Writer fails

Chris Hegarty chris.hegarty at oracle.com
Thu Sep 22 08:57:40 UTC 2011

I see that CR 7015589 was integrated into JDK8 b04.


On 09/22/11 09:40 AM, Jing Lv wrote:
> Hi Alan,
> I see the status of 7015589 has changed to "fix delivered", so is this
> fix in the repository(java8?) already?
> On 2011/8/9 19:43, Alan Bateman wrote:
>> A few months back there was a bug report [1] pointing out that it's
>> possible to continue writing to a BufferedWriter after invoking its
>> close method and the close fails. A similar issue arises with
>> BufferedOutputStream and other classes. At issue is whether a stream
>> (or more generally a resource) is considered closed in the event that
>> the close method fails. This isn't something that Closeable is clear
>> on. Joe tells me that this didn't come up in the Coin discussions on
>> try-with-resources either.
>> I think it's safe to say that it would be desirable that close
>> releases the resources for failing cases as otherwise the resources
>> may never be released (esp. with try-with-resources usages).
>> Furthermore, when there are multiple resources involved, or cases like
>> the bug report where one stream wraps another, then it would be
>> desirable to keep the state of the resources in sync. To that end, the
>> changes here propose adding an advisory note to AutoCloseable to
>> advise implementers to release the underlying resources and to mark
>> the resource as closed prior to throwing the exception.
>> For the specific buffering classes discussed at the time, these are
>> changed to follow this advise (but their javadoc isn't changed as
>> there may be other implementations or these classes extended in many
>> ways). In the case of BufferedWriter it is also fixed so that any
>> exception from flushing the underlying writer isn't supplanted by the
>> exception from close. In the case of FilterOutputStream
>> (BufferedOutputStream extends it) then it is fixed so that it doesn't
>> ignore the exception thrown when flushing the underlying stream. This
>> is clearly the right thing to do but it does mean that close can now
>> throw an IOException for a case where it didn't before. For now I
>> don't propose to include a compatibility switch but this may be
>> something that has to revisited later. There are other classes in
>> java.io that could also be cleaned up but I don't propose to do a
>> complete audit at this time.
>> The webrev with the changes is here:
>> http://cr.openjdk.java.net/~alanb/7015589/webrev/
>> Thanks,
>> Alan.
>> [1]
>> http://mail.openjdk.java.net/pipermail/core-libs-dev/2011-January/005732.html

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