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

[Alexey Ivanov]

On Tue, 17 Dec 2024 14:19:41 GMT, Alexey Ivanov <aivanov at openjdk.org> wrote:

>> src/java.desktop/windows/classes/sun/awt/shell/Win32ShellFolder2.java line 1220:
>> 
>>> 1218:             Image icon = makeIcon(hIcon);
>>> 1219:             if (icon != null && size != icon.getWidth(null)) {
>>> 1220:                 icon = new MultiResolutionIconImage(size, icon);
>> 
>> 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`.

> > 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*.

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PR Review Comment: https://git.openjdk.org/jdk/pull/22776#discussion_r1888645356