<AWT Dev> Review request for 8165829: Android Studio 2.x crashes with NPE at sun.lwawt.macosx.CAccessibility.getAccessibleIndexInParent

[Pete Brunet]

Anton, It looks like you need to also update getInitialAttributeStates. 
-Pete

On 9/16/16 12:49 PM, Anton Tarasov wrote:
> On 9/16/2016 1:32 PM, Sergey Bylokhov wrote:
>> On 15.09.16 14:48, Anton Tarasov wrote:
>>>> Yes, and my suggestion was to use the new method and default values
>>>> everywhere instead of invokeAndWait(Callable,Component).
>>>
>>> But the default value for a reference would be null, there's no need to
>>> request something else, unlike for primitive wrappers.
>>>
>>> Or your idea is to force passing a def value anyway?
>>
>> If the references like Point from getLocationOnScreen() can be null,
>> then ok. looks fine.
>
> Yes, it can.
>
> Anton.
>
>>
>>>
>>> Anton.
>>>
>>>>>> On 15.09.16 12:45, Anton Tarasov wrote:
>>>>>>> Hello,
>>>>>>>
>>>>>>> Please review the fix:
>>>>>>>
>>>>>>> bug: https://bugs.openjdk.java.net/browse/JDK-8165829
>>>>>>> webrev: http://cr.openjdk.java.net/~ant/JDK-8165829/jdk9/webrev.0
>>>>>>>
>>>>>>> (The bug is currently closed as “not an issue”, which is not quite
>>>>>>> true.
>>>>>>> So once and if the fix is approved I can take the ownership of the
>>>>>>> bug).
>>>>>>>
>>>>>>> The problem is this. Sometimes when a frame is closed there may
>>>>>>> appear a
>>>>>>> race condition:
>>>>>>>
>>>>>>> - removeNotify() is called on the frame on EDT and it removes
>>>>>>> all the
>>>>>>> events associated with the frame from the event queue.
>>>>>>>
>>>>>>> - The frame is requested by accessibility via the CAccessibility
>>>>>>> static
>>>>>>> methods (like CAccessibility.getAccessibleIndexInParent). Those
>>>>>>> methods
>>>>>>> are called from native on AppKit thread and they perform via
>>>>>>> invokeAndWait. The latter is wrapped with an InvocationEvent whose
>>>>>>> source is set to the frame. But, once the event is put on the event
>>>>>>> queue, it's purged by the removeNotify() call. As the result,
>>>>>>> invokeAndWait returns null. Then, in some of the mentioned methods
>>>>>>> 'null' is unboxed to a primitive 'int' or 'boolean' which results
>>>>>>> in NPE
>>>>>>> propagated to native. On the native side, the NPE is not properly
>>>>>>> handled and is just re-thrown.
>>>>>>>
>>>>>>> I don't have a simple and safe solution for the race. So, I
>>>>>>> suggest to
>>>>>>> fix the NPE/crash at least.
>>>>>>>
>>>>>>> Thanks,
>>>>>>> Anton.
>>>>>>>
>>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>
>>>>
>>>
>>
>>
>