[8u] RFR(xs): 8068042: Check jdk/src/share/native/sun/misc/URLClassPath.c for JNI pending exception

[Ioi Lam]

On 11/30/15 8:21 PM, David Holmes wrote:
> On 1/12/2015 12:10 PM, Jiangli Zhou wrote:
>> Hi Calvin,
>>
>> I see getUTF() throws OutOfMemoryError if malloc fails before 
>> returning NULL. Do you know if there is any case that getUTF() 
>> returns NULL without throwing any exception? The usage of getUTF() 
>> and exception handling don’t seem to be consistent in existing idk 
>> code. Some places check the NULL return value without throwing a new 
>> exception, while the other places throws a new OOM without checking 
>> for pending exception (like the code you are fixing). Maybe the 
>> callee does not need to re-throw the exception for the NULL return 
>> value case, and you can add a comment saying “an OutOfMemoryError” 
>> has already been thrown by getUTF()?
>
> According to classloader.c:
>
> /* Convert java string to UTF char*. Use local buffer if possible,
>    otherwise malloc new memory. Returns null IFF malloc failed. */
>
> So NULL implies OOME has been thrown. I'd suggest removing the new 
> code and the JNU_ThrowOutOfMemory with a comment as Jiangli suggested.
>
> Also note we have the same kinds of patterns in classLoader.c in 8 and 9.
>
I introduced this bug in URLClassPath.c because I copied the code from 
ClassLoader.c, which had the same pattern, and has been reported in 
https://bugs.openjdk.java.net/browse/JDK-6952230 (5 years!)

- Ioi

> Thanks,
> David
>
>> Thanks,
>> Jiangli
>>
>>
>>> On Nov 30, 2015, at 5:13 PM, Calvin Cheung 
>>> <calvin.cheung at oracle.com> wrote:
>>>
>>> Please review this small fix for adding the check for JNI pending 
>>> exception in URLClassPath.c.
>>>
>>> This fix is only for jdk8u and isn't applicable to 9.
>>>
>>> JBS: https://bugs.openjdk.java.net/browse/JDK-8068042
>>>       (unfortunately it is a closed bug)
>>>
>>> webrev: http://cr.openjdk.java.net/~ccheung/8068042_8u/webrev.00/
>>>
>>> Tests:
>>>     JPRT with -testset hotspot
>>>     RBT hotspot/test/:hotspot_all,vm.regression.testlist, vm.quick
>>>
>>> thanks,
>>> Calvin
>>