Review Request JDK-8201793: (ref) Reference object should not support cloning

Paul Sandoz paul.sandoz at
Fri Apr 27 16:25:43 UTC 2018

> On Apr 26, 2018, at 11:03 PM, mandy chung <mandy.chung at> wrote:
> On 4/27/18 3:35 AM, Paul Sandoz wrote:
>> Hi Mandy,
>> This looks reasonable. I suspect external subtypes of the j.l.ref types are extremely rare (grep code reports no derived types) and of those it would likely be even rarer for those subtypes to implement Cloneable, and for that functionality to operate reliably.
> Thanks for the review.
> Subtypes of java.lang.ref.SoftReference and WeakReference is not uncommon (JDK has plenty of such subtypes). 

Ooops, silly me, grep code only reports direct sub-types when querying for derived types, am i queried from Reference.


> I guess grep code may show the result of a specific JDK release and reports no derived types.  I do think it's extremely rare for those subtypes to implement Cloneable.  So this change should have low compatibility risk.
> Mandy

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