RFR 9: 8165641 : Deprecate Object.finalize

Roger Riggs Roger.Riggs at Oracle.com
Fri Mar 31 17:25:31 UTC 2017

Hi Hans,

Can you suggest how that would be expressed? The advice would seem to 
have some complex conditions.

Would it be the case that a caller using a reference to any resource 
held by a finalizable object
must use reachabilityFence to ensure that the resource can not be 
cleaned up while it is planning to use the resource?

Is there a citation that can supply the context and background for a 
warning or is the explanation
in reachabilityFence sufficient?


On 3/31/2017 1:05 PM, Hans Boehm wrote:
> In my view, the primary reason to prefer Cleaner or PhantomReference 
> is safety (no accidental access to previously finalized objects, which 
> usually turn into dangling pointer dereferences with JNI). Flexibility 
> and efficiency also matter, but I would put them second and third.
> Can we add a warning that it is almost never safe to override 
> finalize() without use of reachabilityFence()?
> On Fri, Mar 31, 2017 at 6:55 AM, Roger Riggs <Roger.Riggs at oracle.com 
> <mailto:Roger.Riggs at oracle.com>> wrote:
>     The webrev for deprecating finalize has been updated:
>      - to improve the advice existing JDK subclasses overriding
>     finalize provides in @deprecated javadoc,
>      - to expand Object.finalize() javadoc to reinforce the correct
>     use of super.finalize() by subclasses,
>      - and to remove redundant @SuppressWarnings annotations.
>     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

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