RFR: 8259343: [macOS] Update JNI error handling in Cocoa code. [v3]

[Sergey Bylokhov]

On Mon, 11 Jan 2021 17:09:14 GMT, Phil Race <prr at openjdk.org> wrote:

>> src/java.desktop/macosx/native/libosxapp/JNIUtilities.h line 41:
>> 
>>> 39:        NSLog(@"%@",[NSThread callStackSymbols]); \
>>> 40:        if ([NSThread isMainThread] == NO) { \
>>> 41:            if ((*env)->ExceptionOccurred(env) == NULL) { \
>> 
>> Not sure that the check for ExceptionOccurred is needed, in all other places where we check the ref to methods/field we only check the return value, and if it is null then return immediately assuming that an exception is rased already, for example :
>> https://github.com/openjdk/jdk/blob/b72de3c5fc99f365e9fb25114ddd28eceddfa6e8/src/java.desktop/windows/native/libawt/windows/awt_Button.cpp#L357
>> 
>> Note that the exception in the static initializer is fatal for the application.
>
>> Not sure that the check for ExceptionOccurred is needed, 
> It may not be needed in practice but if the code path is never taken no harm ...
> 
> in all other places where we check the ref to methods/field we only check the return value, and if it is null then return immediately assuming that an exception is rased already, for example :
>> 
>> https://github.com/openjdk/jdk/blob/b72de3c5fc99f365e9fb25114ddd28eceddfa6e8/src/java.desktop/windows/native/libawt/windows/awt_Button.cpp#L357
>> 
>> Note that the exception in the static initializer is fatal for the application.
> 
> Nothing new here.

The new thing here is that you check the result of the ExceptionOccurred if NULL is returned from the GetMethodID/etc, we usually never do it. If such checks are necessary then I'll create a separate bug to update other similar use cases.

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PR: https://git.openjdk.java.net/jdk/pull/1967