RFR 8223593 : Refactor code for reallocating storage

[Peter Levart]

Hi Ivan,

On 5/9/19 8:07 PM, Ivan Gerasimov wrote:
>> 3. I know that this is not new and has been copied from the old code. 
>> However,
>> I'm not sure I understand the meaning of "unless necessary" here:
>>
>>      /**
>>       * The maximum size of array to allocate (unless necessary).
> It means that if the minimum requested new capacity (oldCapacity + 
> growAtLeastBy) is greater than MAX_ARRAY_SIZE (though still not 
> greater than Integer.MAX_VALUE) then the result *will* be greater than 
> MAX_ARRAY_SIZE.
>
> Current implementation returns Integer.MAX_VALUE in this case.  I was 
> thinking about changing it to returning the actual sum (oldCapacity + 
> growAtLeastBy), but decided not to do that to preserve the behavior.
>
> Practically, it shouldn't matter much, as both variants would likely 
> lead to OOM anyway.
>
> With kind regards,
> Ivan 

Is there a case where returning > MAX_ARRAY_SIZE will not lead to OOME?

If this utility method is meant for re-sizing arrays only (currently it 
is only used for that), then perhaps the method could throw OOME 
explicitly in this case. You already throw OOME for the overflow case, 
so currently the method is not uniform in returning exceptional values 
(i.e. values that lead to exceptions).

Unless you expect some VMs to tolerate arrays as large as 
Integer.MAX_VALUE ?

These lines:

  607         int newCapacity = oldCapacity + preferredGrowBy;
  608         if (preferredGrowBy < growAtLeastBy) {
  609             newCapacity = oldCapacity + growAtLeastBy;
  610         }

...could perhaps be more easily grasped as:

int newCapacity = oldCapacity + Math.max(preferredGrowBy, growAtLeastBy);


Regards, Peter