RFR: 8322135: javax/swing/JTable/JTableScrollPrintTest.java & javax/swing/JTable/PrintAllPagesTest.java throws java.lang.InternalError: HTHEME is null [v2]

[Tejesh R]

On Fri, 19 Apr 2024 19:46:01 GMT, Alexey Ivanov <aivanov at openjdk.org> wrote:

>> src/java.desktop/windows/classes/sun/awt/windows/ThemeReader.java line 120:
>> 
>>> 118:     // this should be called only with writeLock held
>>> 119:     private static Long getThemeImpl(String widget, int dpi) {
>>> 120:         if (openThemeImpl(widget, dpi) == null || openThemeImpl(widget, dpi) == 0) {
>> 
>> I think it would be cleaner and better if this is handled in `openThemeImpl()` itself. We can put a check for NULL `theme `being returned and return the one based on `defaultDPI`, if that is the case.
>
> I agree. The current approach calls `openThemeImpl` three times: once or twice with the passed `dpi` and then once with `defaultDPI` as the fallback. Moreover, it *leaks theme handles* if `openThemeImpl` returns non-zero value and it does so repeatedly even when there's a cached theme handle.
> 
> Handling the failure inside `openThemeImpl` seems a better option. Even though it results in a higher memory usage.
> 
> I believe `openTheme` returns 0 because the DPI of a printer is higher than that of screens, and Windows doesn't support such DPIs. The problem is likely reproducible when you print other components such as buttons.

Yes, `openTheme()` actually returns 0. Hence I used `null` && `0` checker.

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PR Review Comment: https://git.openjdk.org/jdk/pull/18706#discussion_r1574224390