RFR: 8187759: Background not refreshed when painting over a transparent JFrame [v3]

[Abhishek Kumar]

On Tue, 6 Feb 2024 08:08:04 GMT, Tejesh R <tr at openjdk.org> wrote:

>> This is happening in linux where `BuffereStrategyPaintManager` is used to paint to offscreen. Here `bsg` bufferStrategy SunGraphics2D is used to paint to offscreen where the background is not refreshed, which does only clipping and then paints to offscreen. In order to handle the screen updated/clear the buffer, `setBackground` to component background color and `clearRect` against the clip area is used which solves the issue without causing any regression. 
>> CI is green for the fix and manual test is provided.
>
> Tejesh R has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains five additional commits since the last revision:
> 
>  - Review updates - Test automation and updated for transparent comp
>  - Merge branch 'master' of https://git.openjdk.java.net/jdk into branch_8187759
>  - Review fix
>  - Linux tag added
>  - fix + manual test

test/jdk/javax/swing/JFrame/JFrameBackgroundRefreshTest.java line 109:

> 107:             System.out.println("Test Passed!");
> 108:         } finally {
> 109:             if (frame != null) {

should be disposed on EDT.

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PR Review Comment: https://git.openjdk.org/jdk/pull/17081#discussion_r1483932297