Code review request for 6992121: StringBuilder.ensureCapacity(int minCap) throws OutOfMemoryError

[Mandy Chung]

  On 10/18/10 4:54 PM, David Holmes wrote:
> Hi Mandy,
>
> The functional changes seem ok. However the ArrayList test is not 
> right because it checks the size not the capacity. The same with the 
> Vector test, though at least with Vector you can check capacity().
>

I missed the Vector.capacity() method.  Thanks.   I updated the test.
    http://cr.openjdk.java.net/~mchung/6992121/webrev.01/
> I find it odd that ArrayList has a very well defined notion of 
> capacity yet no method to query that capacity.
>

True.  I don't have the history but wonder if this is intentional.

Mandy

> David
>
> Mandy Chung said the following on 10/19/10 08:41:
>>  Please review the fix for:
>>
>> 6992121: StringBuilder.ensureCapacity(int minCap) throws 
>> OutOfMemoryError with minCap=Integer.MIN_VALUE
>>
>> Webrev at:
>>     http://cr.openjdk.java.net/~mchung/6992121/webrev.00/
>>
>> This is a regression caused by the changes for 6933217 (Huge arrays 
>> handled poorly in core libraries).   The ensureCapacity() method in 
>> the StringBuffer, StringBuilder, ArrayList, and Vector classes are a 
>> public API that accepts negative numbers.   The following 
>> overflow-conscious code:
>>
>>   if (minimumCapacity - value.length>  0)
>>
>> considers negative minimumCapacity as overflow case where 
>> OutOfMemoryError will be thrown.  So the implementation of the public 
>> ensureCapacity() methods need to check if the input argument is 
>> positive before doing the above overflow-conscious check.
>>
>> Thanks
>> Mandy