Bugs in java.util.ArrayList, java.util.Hashtable and java.io.ByteArrayOutputStream

[Kevin L. Stern]

FYI, HashMap independently defines a MAXIMUM_CAPACITY variable; it might be
a good idea to retrofit this and other such local definitions with any
system wide variables that are defined.

    /**
     * The maximum capacity, used if a higher value is implicitly specified
     * by either of the constructors with arguments.
     * MUST be a power of two <= 1<<30.
     */
    static final int MAXIMUM_CAPACITY = 1 << 30;

Regards,

Kevin

On Fri, Mar 5, 2010 at 4:06 AM, Ulf Zibis <Ulf.Zibis at gmx.de> wrote:

> Am 05.03.2010 10:04, schrieb Martin Buchholz:
>
>  Hi Kevin,
>>
>> As you've noticed, creating objects within a factor of two of
>> their natural limits is a good way to expose lurking bugs.
>>
>> I'm the one responsible for the algorithm in ArrayList.
>> I'm a bit embarrassed, looking at that code today.
>> We could set the array size to Integer.MAX_VALUE,
>> but then you might hit an independent buglet in hotspot
>> that you cannot allocate an array with Integer.MAX_VALUE
>> elements, but Integer.MAX_VALUE - 5 (or so) works.
>>
>>
>
> I think, using a max size of Integer.MAX_VALUE - x looks awful, in
> particular if it's badly commented in the sources.
> I suggest to introduce something like System.MAX_COLLECTION_SIZE/CAPACITY
> or .maxCollectionSize/Capacity().
>
> -Ulf
>
>
>
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