Finalizer being run while class still in use (escape analysis bug)
aph at redhat.com
Thu Oct 11 09:29:11 UTC 2018
On Wed, Oct 10, 2018 at 9:53 AM Kim Barrett <kim.barrett at oracle.com> wrote:
> Finalization was deprecated in JDK 9 (*). There's an ongoing (though
> progressing slowly) process of eliminating its usage in the JDK.
> Sometime after that it may go away entirely, or perhaps require some
> sort of explicit opt-in, making it possible to eliminate various GC
> overheads associated with it.
> (*) Use PhantomReference, or a helper like java.lang.ref.Cleaner.
> Though that change the liveness question in this thread.
It doesn't matter whether finalization is used or PhantomReferences,
or whatever. The problem of "early" collection remains the same on
every possible mechanism which relies on the GC to trigger cleanup, so
reachabilityFence still has to be used to prevent early collectiona
The existence of PhantomReference does show, however, why treating
classes with finalizers in a special way is pointless. Hans Boehm's
proposal for an annotation such as @Cleaned on the class makes the
most sense, IMO. But we can probably live with reachabilityFence,
although it's a horrible name.
Java Platform Lead Engineer
Red Hat UK Ltd. <https://www.redhat.com>
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