performance surprise with Object.hashCode()

Aleksey Shipilev aleksey.shipilev at oracle.com
Mon May 13 13:31:01 PDT 2013


On 05/14/2013 12:27 AM, Vitaly Davidovich wrote:
> Why would o_i without intrinsic need a typecheck? Every object has
> hashCode, it should be just a vcall.  

You do the typecheck to check it is indeed Integer, and call
Integer.hashCode() directly. *Avoiding* the vcall is what makes both i_i
and o_i (without intrinsic) faster.

-Aleksey.


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