On 11/15/2013 10:04 PM, John Rose wrote:
On Nov 14, 2013, at 7:21 PM, Joseph Darcy <joe.da...@oracle.com> wrote:
Catching up on email, the specification of java.lang.Class does not explicitly
promise that its notion of equality must be identity for all time. Therefore,
while not required for today's implementations, I would prefer that new code we
write in the JDK use equals rather than == when comparing classes.
There's no possible future where java.lang.Class would return true for equals
but false for == (acmp). So there's no future-proofing to do here.
Reification of generics might require something like this, but we could not break class
identity without (as others have pointed out) breaking compatibility with a huge amount
of code "in the wild".
Before that would happen, we would introduce a new auxiliary type (e.g.,
java.lang.Species and java.lang.Object::getSpecies) that would represent the
richer view of an object's runtime type.
I do hope, in a future release, to "hack" reference equality, but in a
different direction, allowing == (acmp) to return true *more often*, not allowing it to
return *less often*. The point will be to align the semantics of equals and acmp *more*
closely for some types, notably the wrappers and java.lang.String. (Interned referneces
are so last-century.)
— John
+1
I think I prefer Variety to Species to get ride of the ambiguous plural.
Rémi
