The test program supplied here can be used to demonstrate that with the
2D metal pipeline a window is created whilst the application is in display sleep
then the window is never painted, no matter what you do after returning from sleep.

It was reported as a JDK 19 issue on macOS 13 (JDK 19 is
the release in which metal was turned on by default) but I reproduced
on macOS 12.6 with JDK 18 by specifying -Dsun.java2d.metal=True
It passes (repaint happens) if you use OpenGL on both of these releases.


import java.awt.FlowLayout;
import java.awt.Toolkit;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.SwingUtilities;
import javax.swing.Timer;

public class TestRenderStop {
    MyFrame fr;

    public TestRenderStop() {
        JFrame m = new MyFrame("Test Render Stop", "Enter display sleep [control-shift-Eject] now and wait until you hear the beep before typing Enter to resume");
        m.setBounds(400, 400, 800, 400);
        m.setVisible(true);

        Timer t = new Timer(10000, e -> showFrame());
        t.setRepeats(false);
        t.start();
    }

    private void showFrame() {
        fr = new MyFrame("Test Frame", "This is a label");
        fr.setBounds(500, 550, 400, 70);
        fr.setVisible(true);
        Toolkit.getDefaultToolkit().beep();
    }

    class MyFrame extends JFrame {
        MyFrame(String title, String message) {
            setTitle(title);
            setLayout(new FlowLayout());
            add(new JLabel(message));
        }
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(TestRenderStop::new);
    }
}