I share the same concern. clone() is a heavy weight operation in
constructors that can be called alot during intensive crypto operations.
Now that you've done work on Delegate class - why not also keep the
(instanceof Cloneable) test ? That can serve as your fastpath for the
default JDK configuration AFAIK.
regards,
Sean.
On 05/06/2020 00:16, Weijun Wang wrote:
在 2020年6月5日，03:19，Valerie Peng <valerie.p...@oracle.com> 写道：
Can you give an example when these 2 rules have different results? Is this only
true for those implementation that directly subclass MessageDigest?
Before this fix, even the Spi impl implements Cloneable the instanceof check
will always fail because the wrapper class, i.e. MessageDigest.Delegate does
not. However, if you call the clone() (made public by the MessageDigest class),
it will succeed because Delegate.clone() checks to see if the spi object
implements the Cloneable interface, if yes, it will proceed to call the spi
clone(). So, for this scenario, the results are different, e.g. instanceof
returns false, but clone() succeeds. This is just one example. Is this what you
are asking?
No.
I understand this case, but this has already been fixed. Is there any other
example? Or are you only follow the words in the spec? i.e. try clone() to see
if it’s cloneable.
I am worried that try clone() is much heavier than just check instanof
Cloneable.
Thanks,
Max
