On 03/05/2014 01:04, Bernd Eckenfels wrote:
Hello,
back in 2011 there was a discussion about the new changed behavior of
FilterOutputStream (and BufferedOutputStream) in regards to not anymore
swalloging IOExceptions from flush() on this list (thats where I got
the subject from).
This was generally a very good improvement (and I am glad that
https://bugs.openjdk.java.net/browse/JDK-6335274 thereby got fixed).
However the implementation with the try-with-resource has a problem:
when flush() and close() report the same exception instance the
construction of the suppressed exception will actually fail with an
IllegalArgumentException.
This IllegalArgumentException of Throwable.addSuppressed is very
unfortunate (it would be better simply ignore it).
Anyway, this new behavior broke a Unit-Test for Apache VFS as you can
see here: https://issues.apache.org/jira/browse/VFS-521
I think this can only be fixed in Throwable by avoiding this
IllegalArgumentException or by the close() method not using
try-with-resource.
For reference, according to this changeset other locations are affected
as well:
http://hg.openjdk.java.net/jdk8/jdk8/jdk/rev/759aa847dcaf
Thanks this bug report, I've created JDK-8042377 to track it. I don't
think this has come up before, probably because flush and close are more
likely to throw new exceptions rather than equal (cached) exceptions.
I don't see this issue as driver to changing Throwable to support self
suppression but we can change BufferedWriter and FilteredOuputStream to
only add the suppressed exception when they are not equal.
-Alan.
