RFR 8218227 : StringBuilder constructor throws confusing NegativeArraySizeException

[Roger Riggs]

Hi Ivan,

Can we put the new StringBuffer tests into the existing 
StringBuffer.Capacity.java test?
It can help keep functional test pieces to together and not create n+1 
files.

Looking back I would have preferred the same for the StringBuilder.Huge 
tests.
There is a Capacity.java test there too.  But the tests have diverged.

Thanks, Roger


On 02/04/2019 04:25 PM, Ivan Gerasimov wrote:
> Thank you Roger for reviewing!
>
>
> On 2/4/19 11:32 AM, Roger Riggs wrote:
>> Hi Ivan,
>>
>> A good boundary condition to clean up.
>>
>> Should tests for StringBuffer be added too?
>>
> Yes, let's add them.
>
> Please find the updated webrev here:
> http://cr.openjdk.java.net/~igerasim/8218227/01/webrev/
>
> With kind regards,
> Ivan
>
>> Maxing out the length at MAX_VALUE must always result in an OOM.
>> If such an allocation were to succeed, it would violate the specified 
>> initial capacity requirement.
>>
>> Thanks, Roger
>>
>>
>> On 02/02/2019 02:28 AM, Ivan Gerasimov wrote:
>>> Hello!
>>>
>>> The spec of the constructors 
>>> StringBuilder(String)/StringBuilder(CharSequence) states that the 
>>> initial capacity of the builder will be set to the length of the 
>>> argument plus 16.
>>> This causes them to throw confusing NegativeArraySizeException when 
>>> the argument's length is close to Integer.MAX_VALUE.
>>>
>>> Let the arguments length be (Integer.MAX_VALUE - DELTA), like in the 
>>> code below:
>>>
>>>         String str = "Z".repeat(Integer.MAX_VALUE - DELTA);
>>>         StringBuilder sb = new StringBuilder(str);
>>>
>>> Currently the behavior is as following:
>>>     0 <= DELTA <= 2 - unable to construct str,
>>>     2 <= DELTA <= 15 - NegativeArraySizeException is thrown,
>>>     16 <= DELTA <= 17 - OutOfMemoryError is thrown,
>>>     DELTA >= 18 - works fine.
>>>
>>> With the fix, OOM will be thrown for all DELTA <= 17.
>>>
>>> Also the fix will make constructing a StringBuilder from UTF16 coded 
>>> String slightly more efficient.
>>>
>>> BUGURL: https://bugs.openjdk.java.net/browse/JDK-8218227
>>> WEBREV: http://cr.openjdk.java.net/~igerasim/8218227/00/webrev/
>>>
>>> Would you please help review the fix?
>>>
>>
>>
>