Possible HashSet memory improvement

[Remi Forax]

On 10/06/2013 08:09 PM, Philippe Marschall wrote:
>
>
> On 05.10.2013 21:57, Brian Goetz wrote:
>>> Is there something I missed? Is this something that has been 
>>> considered?
>>
>> If memory efficiency were the only metric in the world, this would be 
>> a no-brainer.  But, by having different classes for different nodes, 
>> many many paths where the VM could prove monomorphism and thereby 
>> inline through now become polymorphic and at best could be inline 
>> cached.
>>
>> ...
>>
>
> Doesn't the rb-tree collision handling in HashMap already introduce 
> different classes for different nodes (Node and TreeNode)? Or is the 
> assumption there that this doesn't happen in production and therefore 
> does not introduce polymorphism?

The actual code carefully introduces polymorphism only if there is an 
abnormal number of collisions,
either because a method hashCode() is badly written or someone tries to 
DDOS the HashMap.

>
> Cheers
> Philippe

cheers,
Rémi