[9] RFR(XS): 8076625: IndexOutOfBoundsException in HeapByteBufferTest.java

[Tobias Hartmann]

Hi Vladimir,

On 09.04.2015 18:22, Vladimir Kozlov wrote:
> I also asked to use Utils::getRandomInstance() to get reproducible results.

Sorry, I missed that. Here is the new webrev:

http://cr.openjdk.java.net/~thartmann/8076625/webrev.01/

I also noticed that the sizes of short and char reads passed to 'randomOffset' are too large (4 instead of 2). Fixed it.

Best,
Tobias


> Thanks,
> Vladimir
> 
> 
> On 4/9/15 5:10 AM, Tobias Hartmann wrote:
>> Hi,
>>
>> please review the following patch.
>>
>> https://bugs.openjdk.java.net/browse/JDK-8076625
>> http://cr.openjdk.java.net/~thartmann/8076625/webrev.00/
>>
>> Problem:
>> A random offset to access in a byte array is computed by
>>
>>    int randomOffset(SplittableRandom r, MyByteBuffer buf, int size) {
>>      return abs(r.nextInt()) % (buf.capacity() - size);
>>    }
>>
>> The call to r.nextInt() may return Integer.MIN_VALUE (-2147483648) and the corresponding absolute value (+2147483648) does not fit into an int and will overflow back to -2147483648. As a result the returned offset is negative.
>>
>> Solution:
>> Use nextInt(int n) to set the limit of the random value.
>>
>> Testing:
>> Failing testcase and JPRT.
>>
>> Thanks,
>> Tobias
>>