Idea how to implement VT/VO compatibility in JVM

Vitaly Davidovich vitalyd at
Thu Jan 22 14:42:15 UTC 2015

Ok can we first agree that List <T> is NOT List <Object>? :) That's unsound
since you can't add any Object in there if things are reified.  I think you
guys mean List <?>.

sent from my phone
On Jan 22, 2015 9:34 AM, "Stéphane Épardaud" <stef at> wrote:

> On 01/22/2015 03:30 PM, Vitaly Davidovich wrote:
>> I don't quite get the elegance comment - there's already nothing elegant
>> about heavy use of reflection.  Yes, it gets the job done in some cases,
>> but it's a minority use case (I hope!).
>>  Well, IMO there's a lot more elegance in List<val Date> being an
> instance of List<Object> (variance issues aside).
>> Also, keep in mind that calling a Collection <?> taking method with value
>> type collections may not be safe as the code in that method may be relying
>> on Object semantics (e.g. locks on objects, compares reference identity,
>> etc); in some ways it's safer to call any T methods because presumably
>> person writing those is conscious of value types being a possibility and
>> also compiler may warn if any assumptions are made about it being an Object.
>>  Sure, except it needs to be possible to do ;)

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