RFR: 7161229 - PriorityBlockingQueue keeps hard reference to last removed element
Alan.Bateman at oracle.com
Tue Jun 26 16:35:27 UTC 2012
On 25/06/2012 05:26, David Holmes wrote:
> When removing the last element from the PBQ the "sift down" logic
> would store it back in as array. The simple fix is for the
> sift-down to be a no-op if the queue size is zero.
> The fix has been contributed by Doug Lea. We are taking this
> opportunity to synchronize PBQ with Doug's latest version at:
> So in addition to the above functional fix there are a number of
> miscellaneous code and comment cleanups. The only non-trivial, but
> still very simple, change is to the drainTo method to make it more
> robust if the add() on the destination collection throws an exception.
> I am of course a Reviewer for this.
> I have provided the update to the LastElement test (as this is
> certainly related to the last element) but there are some reservations
> about examining the PBS internals this way. Unfortunately there is no
> good way to test for these kinds of retention issues. You either need
> a whitebox test like this, or need to rely on non-guaranteed GC and
> finalization behaviour.
I looked through the changes to siftDown* and the other clean-ups and
they look fine to me.
As this test doesn't set a security manager then I assume it doesn't
really need L92-94. It is a bit icky to use reflection and pull out a
private field but I don't think it's is easily tested otherwise.
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