RFR: 8316627: JViewport Test headless failure [v3]

[Phil Race]

On Wed, 20 Sep 2023 21:53:09 GMT, Phil Race <prr at openjdk.org> wrote:

>> test/jdk/javax/swing/JViewport/bug4546474.java line 51:
>> 
>>> 49:         if (!viewChanged) {
>>> 50:             viewChanged = true;
>>> 51:         }
>> 
>> What purpose does viewChanged have ?
>> Its set but never read.
>
> The adjustmentListener therefore seems irrelevant too.

Seems to me the test reduces to
import javax.swing.JPanel;
import javax.swing.JScrollBar;
import javax.swing.JScrollPane;

public class bug4546474 {
 
    public static void main(String[] args) {
        JPanel panel = new JPanel();
        JScrollPane  scrollpane = new JScrollPane(panel,
                JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
                JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
        JScrollBar sbar = scrollpane.getVerticalScrollBar();
        scrollpane.setViewportView(null);

        if (sbar.getVisibleAmount() > 0) {
            throw new RuntimeException("Vertical scrollbar is not " +
                    "updated when viewport is replaced");
        }
    }
}

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PR Review Comment: https://git.openjdk.org/jdk/pull/15847#discussion_r1332223256