RFR 9: 8165641 : Deprecate Object.finalize

[Roger Riggs]

Hi,

A common cleaner was considered but it would be susceptible to one of 
the same problems
as finalizers. A bug in the cleanup code could block the thread due to 
locks or deadlock,
and hold up cleanup for all of its clients.  It would be an attractive 
nuisance.
Library or modules can create a cleaner shared and any issues can be 
resolved within that context.

Roger


On 3/10/2017 9:15 PM, Hans Boehm wrote:
> IIUC, all of the replacements for finalizers (Cleaners, 
> PhantomReferences) still have the problem that they can't easily share 
> a single thread across separately-developed libraries to actually run 
> the cleanups? It seems to me that has been the only even 
> halfway-convincing reason to still use finalizers for a long time, but 
> it seems to be a pretty good one in practice.
>
>
> On Fri, Mar 10, 2017 at 5:36 PM, Kim Barrett <kim.barrett at oracle.com 
> <mailto:kim.barrett at oracle.com>> wrote:
>
>     > On Mar 10, 2017, at 4:40 PM, Roger Riggs <roger.riggs at oracle.com
>     <mailto:roger.riggs at oracle.com>> wrote:
>     >
>     > Finalizers are inherently problematic and their use can lead to
>     performance issues,
>     > deadlocks, hangs, and other problematic behavior.
>     >
>     > The problems have been accumulating for many years and the first
>     step to
>     > deprecate Object.finalize and the overrides in the JDK to
>     communicate the
>     > issues, recommend alternatives, and motivate changes where
>     finalization is currently used.
>     >
>     > The behavior of finalization nor any uses of finalize are not
>     modified by this change.
>     > Most of the changes are to suppress compilation warnings within
>     the JDK.
>     >
>     > Please review and comment.
>     >
>     > Webrev:
>     >
>     http://cr.openjdk.java.net/~rriggs/webrev-finalize-deprecate-8165641/
>     <http://cr.openjdk.java.net/%7Erriggs/webrev-finalize-deprecate-8165641/>
>     >
>     > Issue:
>     > https://bugs.openjdk.java.net/browse/JDK-8165641
>     <https://bugs.openjdk.java.net/browse/JDK-8165641>
>     >
>     > Thanks, Roger
>
>     looks good.
>
>
>