Java Window pulse-fader works once then breaks

Question

Ok, I've got some code I setup to create a simple little overlay window to use as an alert message for a program I'm working on. Everything works fine the first run through, but trying to run through it again, it freezes the whole thing, forcing me to terminate it via the debugger or task manager. I know I'm doing something wrong, I'm just not sure what, due to my limited experience with Java.

Below is the code I use to setup my window and place it in the lower-right corner above the taskbar:

private static Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
public static JWindow alertWindow() {
    JWindow newWin = new JWindow();

    JPanel panel = new JPanel();

    BufferedImage img = null;
    try {
        img = ImageIO.read(Main.class.getResource("/images/test.jpg"));
    } catch (IOException e) {
        e.printStackTrace();
    }
    JLabel imgLbl = new JLabel(new ImageIcon(img));

    panel.add(imgLbl);
    newWin.setContentPane(panel);
    newWin.pack();

    Insets scnMax = Toolkit.getDefaultToolkit().getScreenInsets(newWin.getGraphicsConfiguration());
    int taskBar = scnMax.bottom;
    int x = screenSize.width - newWin.getWidth();
    int y = screenSize.height - taskBar - newWin.getHeight();
    newWin.setLocation(x,y);
    newWin.setVisible(true);

    final PulseWindow pulseWin = new PulseWindow(newWin);
    pulseWin.getWindow().addMouseListener(new MouseListener() {
        @Override
        public void mouseClicked(MouseEvent click) {
            if(SwingUtilities.isRightMouseButton(click)) {
                pulseWin.stopPulsing();
                pulseWin.destroyPulse();
            } else {
                System.out.println(pulseWin.isPulsing());
                if(pulseWin.isPulsing()) {pulseWin.stopPulsing();}
                else {pulseWin.startPulse();}
            }
        }
        @Override
        public void mouseEntered(MouseEvent arg0) {}
        @Override
        public void mouseExited(MouseEvent arg0) {}
        @Override
        public void mousePressed(MouseEvent arg0) {}
        @Override
        public void mouseReleased(MouseEvent arg0) {}
    });
    pulseWin.startPulsing();

    return newWin;
}

And below is the code I've setup to make it pulse to draw the user's attention:

import javax.swing.JWindow;

public class PulseWindow {

private boolean pulse = true;
private boolean doPulse = true;
private Float floor = 0.50f;
private JWindow win;

public PulseWindow(JWindow win) {
    this.win = win;
}

public void startPulsing() {
    pulse = true;
    boolean decreasing = true;
    double inc2 = 0.03;
    double current = win.getOpacity();

    while(pulse) {
        if(doPulse) {
            if(decreasing) {
                current = current - inc2;

                if((float) current <= floor) {
                    current = floor;
                    win.setOpacity((float) current);
                    decreasing = false;
                } else {
                    win.setOpacity((float) current);
                }
            } else {
                current = current + inc2;

                if((float) current >= 1.0f) {
                    current = 1.0;
                    win.setOpacity((float) current);
                    decreasing = true;
                } else {
                    win.setOpacity((float) current);
                }
            }
        } else {
            current = 1.0;
            win.setOpacity(1.0f);
            decreasing = true;
        }
        try {
            Thread.sleep(100);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
    win.setOpacity(1.0f);
}

public void destroyPulse() {
    pulse = false;
    win.dispose();
}

public boolean isPulsing() { return doPulse; }
public void setFloor(float floor) { this.floor = floor; }
public void stopPulsing() { doPulse = false; }
public void startPulse() { doPulse = true; }
public JWindow getWindow() { return win; }
}

Anyway, like I mentioned, it works fine for the first use, but as soon as you close the window via the right-click then attempt to re-run it later (whether by calling the startPulsing() method or by completely reinitializing the whole class with a new JWindow by calling alertWindow() again), the whole program freezes. Any ideas why this is?

Like I said, I'm still a bit of a newbie to Java, so if you see anything else I'm doing wrong/inefficiently, as well, feel free to point it out so I can do it correctly.

Edit:

I'm starting to think the issue is with JWindows, now. I setup some other code for a different method of displaying the alert and, while it doesn't freeze this time, it doesn't work as intended, either.

public class AlertWindow extends JWindow {

private static Border compound = BorderFactory.createCompoundBorder(BorderFactory.createRaisedBevelBorder(), BorderFactory.createLoweredBevelBorder());
private static Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();

public AlertWindow() {      
    JPanel panel = new JPanel();
        panel.setBorder(compound);
        panel.setBackground(Color.RED);

    JLabel imgLbl = new JLabel("Enter Alert Msg Here!");
        imgLbl.setFont(new Font(null,Font.BOLD,16));

    panel.add(imgLbl);
    setContentPane(panel);
    pack();


    this.addMouseListener(new MouseListener() {
        @Override
        public void mouseClicked(MouseEvent click) {
            if(SwingUtilities.isLeftMouseButton(click)) {
                scrollOff();
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                scrollOn();
            }
        }
        @Override
        public void mouseEntered(MouseEvent arg0) {}
        @Override
        public void mouseExited(MouseEvent arg0) {}
        @Override
        public void mousePressed(MouseEvent arg0) {}
        @Override
        public void mouseReleased(MouseEvent arg0) {}
    });
    scrollOn();
}

public void scrollOn() {
    Insets scnMax = Toolkit.getDefaultToolkit().getScreenInsets(getGraphicsConfiguration());
    int taskBar = scnMax.bottom;
    int x = screenSize.width - getWidth();
    int yEnd = screenSize.height - taskBar - getHeight();
    int yStart = screenSize.height;
    setLocation(x,yStart);
    setVisible(true);
    int current = yStart;
    while(current > yEnd) {
        current-=2;
        System.out.println(current);
        setLocation(x,current);
        try {
            Thread.sleep(30);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}
public void scrollOff() {
    int x = screenSize.width - getWidth();
    int yEnd = screenSize.height;
    int yStart = this.getBounds().y;
    setLocation(x,yStart);
    int current = yStart;
    while(current < yEnd) {
        current+=2;
        setLocation(x,current);
        try {
            Thread.sleep(30);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
    setVisible(false);
}
}

Just like the pulsing window issue, it works as intended the first time, then breaks on subsequent uses. In this case, the only thing that breaks is the scrollOn() command. It scrolls on while invisible, then becomes visible once it reaches its destination. The console output of the position clearly shows that it's moving, but you can't see it until it stops moving.

Answer 1

Edit 2:

And back to feeling dumb... I found the issue (actually found it some time ago but forgot to update this...). The issue ended up being that I was only using the runnable and not placing it inside of a new Thread() object. For some reason I was thinking runnable objects created their own new threads, but once I figured out my mistake, it was an easy fix. Obviously I still have a long ways to go in learning Java...

---

Edit:

Ok, now I'm annoyed... apparently it still breaks if you attempt to run it from an action listener of some kind. My most recent version of the PulseAlert class (below) that calls into the PulseWindow class shown in the original answer further below:

public class PulseAlert {

private static Border compound = BorderFactory.createCompoundBorder(BorderFactory.createRaisedBevelBorder(), BorderFactory.createLoweredBevelBorder());
private static Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();

public void runAlert() throws InterruptedException {
    final PulseWindow pulseWin = new PulseWindow(alertWindow());
    pulseWin.getWindow().addMouseListener(new MouseListener() {
        @Override
        public void mouseClicked(MouseEvent click) {
            if(SwingUtilities.isRightMouseButton(click)) {
                pulseWin.stopPulsing();
                pulseWin.destroyPulse();
            } else if(SwingUtilities.isLeftMouseButton(click) && pulseWin.isPulsing()) {
                pulseWin.stopPulsing();
            } else if(SwingUtilities.isLeftMouseButton(click) && !pulseWin.isPulsing()) {
                pulseWin.startPulsing();
            }
        }
        @Override
        public void mouseEntered(MouseEvent arg0) {}
        @Override
        public void mouseExited(MouseEvent arg0) {}
        @Override
        public void mousePressed(MouseEvent arg0) {}
        @Override
        public void mouseReleased(MouseEvent arg0) {}
    });
    try {
        pulseWin.startPulse();
    } catch (Exception e) {
        e.printStackTrace();
    }
    while(pulseWin.pulserActive()) {
        Thread.sleep(100);
    }
    System.out.println("done with second SW");
}

public static JWindow alertWindow() {
    System.out.println("Start");
    JWindow newWin = new JWindow();

    JPanel panel = new JPanel();
        panel.setBorder(compound);
        panel.setBackground(Color.RED);

    JLabel imgLbl = new JLabel("Enter Alert Msg Here!");
        imgLbl.setFont(new Font(null,Font.BOLD,16));

    panel.add(imgLbl);
    newWin.setContentPane(panel);
    newWin.pack();

    Insets scnMax = Toolkit.getDefaultToolkit().getScreenInsets(newWin.getGraphicsConfiguration());
    int taskBar = scnMax.bottom;
    int x = screenSize.width - newWin.getWidth();
    int y = screenSize.height - taskBar - newWin.getHeight();
    newWin.setLocation(x,y);
    newWin.setVisible(true);

    return newWin;
}
}

And below is how I can call up the alert window - repeatedly, if I like, as long as it's outside of an action listener.

PulseAlert alertPulse = new PulseAlert();
alertPulse.runAlert();

The above code works flawlessly until placed into an action listener of some kind such as:

trayIcon.addActionListener(new ActionListener() {
    public void actionPerformed(ActionEvent e) {
        try {
            alertPulse.runAlert();
        } catch (InterruptedException e1) {
            e1.printStackTrace();
        }
    }
});

Once the runAlert() method is called from an action listener, the whole thing freezes like it did previously. Runs perfectly fine until then. Any ideas what is causing this? Is this a bug in Java or am I doing something wrong?

---

Original Answer:

Ok, I feel pretty dumb, now. All I had to do to fix the issue was place the startPulsing() contents into a new runnable and it all works, and as many times as I need it to.

public void startPulsing() throws Exception {
    new Runnable() {
        @Override
        public void run() {
            pulse = true;
            win.setVisible(true);
            boolean decreasing = true;
            double inc = 0.05;
            double current = win.getOpacity();

            while(pulse) {
                if(doPulse) {
                    if(decreasing) {
                        current = current - inc;

                        if((float) current <= floor) {
                            current = floor;
                            win.setOpacity((float) current);
                            decreasing = false;
                        } else {
                            win.setOpacity((float) current);
                        }
                    } else {
                        current = current + inc;

                        if((float) current >= 1.0f) {
                            current = 1.0;
                            win.setOpacity((float) current);
                            decreasing = true;
                        } else {
                            win.setOpacity((float) current);
                        }
                    }
                } else {
                    current = 1.0;
                    win.setOpacity(1.0f);
                    decreasing = true;
                }
                try {
                    Thread.sleep(100);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
            win.setOpacity(1.0f);
        }
    }.run();
}