RFR: JDK-8344907 : NullPointerException in Win32ShellFolder2.getSystemIcon when "icon" is null

[Alexander Zuev]

On Tue, 17 Dec 2024 14:49:34 GMT, Alexey Ivanov <aivanov at openjdk.org> wrote:

>> I'd leave it out here. As @azuev-java [notes above](https://github.com/openjdk/jdk/pull/22776/files#r1887863199), the likely problem is `hIcon == 0` rather than `makeIcon` returns `null`.
>
>> > Although `icon != null` check is not strictly required here due to `hIcon != 0` check, added it as sanity check and to be consistent with other locations in Win32ShellFolder2.java where makeIcon() is called (which is followed by a null check for the returned icon).
>> 
>> I'd leave it out here. As @azuev-java [notes above](https://github.com/openjdk/jdk/pull/22776/files#r1887863199), the likely problem is `hIcon == 0` rather than `makeIcon` returns `null`.
> 
> Now that I've thought about it more, you're right `icon != null` is also needed… if the icon bits can't be extracted which can also occur if *GDI resources are exhausted*.

Then i would suggest doing both checks in both places. No need to even try to extract icon bits for hIcon == 0 but if we failed to extract icon for the correct handle we should handle it too.

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PR Review Comment: https://git.openjdk.org/jdk/pull/22776#discussion_r1888900624