Threading issue - Unable to dispose of Window running in a separate thread

This would be a model of a larger application, that doesn't work either. Actually it is not fully accurate as a model
because instead of the timer I run a Windows executable in the 'real' app that returns a value and that will give the delay, not a timer. If I have any further trouble after solving it at this level - with the timer - I may post another one
I just don't even know if I can get the particular exe running without its environment and returning any value I can use in my Java program, for the demo.

So, for now if you start SelectProject where the main() method is,  then it will start a MainScreenMini3.java instance.
When you press the button both the timer starts and an instance of HourGlassWindow.java is created.
Which is essentially just a JWindow containing the animated gif 'HourGlass1.gif'.

When you press the button again the timer stops, but I don't seem to be able to create an interrupt to
the hourglass window thread that will dispose of my running HourGlassWindow.java instance.
So that when the next time the button is pushed a new instance of the hourglass window is created,
relative to the current position of the MainScreenMini3.java JFrame instance on the screen, so that it
occupies the same area over this JFrame, on top of the JFrame.

So this is how it looks, when running:

And the 3 classes necessary:

1.  SelectProject.java, which will just pick a folderon your c:\ root and pass the path down to MainScreenMini3.java:

import java.awt.*;
import java.awt.event.*;
import java.io.File;
import javax.swing.*;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;

public class SelectProject extends JFrame {
	
	// Variables declaration 
	private JLabel jlblSelectTest;
	private JScrollPane scrollPane1;
        private DefaultListModel model; 
	private JList jlstProjectList;
	private JButton jbtnOpenProject;
	// End of variables declaration 
        
        private String selectionLine = "";
        
        // Class level declare instance of child window
        private MainScreenMini3 mainScreenMini3;
        
        
	public SelectProject() {
	   super("BST Program ITC version 1.1 - Select Project" ); 
	        initComponents();
	    try {
	        // Set the look and feel for the current OS (Windows) Scheme
	        UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
	                initComponents();
            } catch (Exception e) {
                e.printStackTrace();
	                    }
            this.setSize(388,380);
	    this.setResizable(false);
            this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            this.setVisible(true);
	}

	private void initComponents() {
		// Component initialization 
		jlblSelectTest = new JLabel();
		scrollPane1 = new JScrollPane();
                model = new DefaultListModel();
                jlstProjectList = new JList(model);
                
		jbtnOpenProject = new JButton();

		//======== this ========
		Container contentPane = getContentPane();
		contentPane.setLayout(null);

		//---- jlblSelectTest ----
		jlblSelectTest.setText("Select Test Project to Open:");
		jlblSelectTest.setFont(new Font("Tahoma", Font.BOLD, 14));
		jlblSelectTest.setHorizontalAlignment(SwingConstants.CENTER);
		contentPane.add(jlblSelectTest);
		jlblSelectTest.setBounds(50, 10, 260, 25);

		//======== scrollPane1 ========
		{
			scrollPane1.setViewportView(jlstProjectList);
		}
		contentPane.add(scrollPane1);
		scrollPane1.setBounds(20, 45, 340, 245);

		//---- jbtnOpenProject ----
		jbtnOpenProject.setText("Open Project");
		jbtnOpenProject.setFont(new Font("Tahoma", Font.BOLD, 12));
		jbtnOpenProject.addActionListener(new ActionListener() {
			
			public void actionPerformed(ActionEvent e) {
				jbtnOpenProject_ActionPerformed(e);
			}
		});
		contentPane.add(jbtnOpenProject);
		jbtnOpenProject.setBounds(125, 305, 120, jbtnOpenProject.getPreferredSize().height);

		{ // compute preferred size
			Dimension preferredSize = new Dimension();
			for(int i = 0; i < contentPane.getComponentCount(); i++) {
				Rectangle bounds = contentPane.getComponent(i).getBounds();
				preferredSize.width = Math.max(bounds.x + bounds.width, preferredSize.width);
				preferredSize.height = Math.max(bounds.y + bounds.height, preferredSize.height);
			}
			Insets insets = contentPane.getInsets();
			preferredSize.width += insets.right;
			preferredSize.height += insets.bottom;
			contentPane.setMinimumSize(preferredSize);
			contentPane.setPreferredSize(preferredSize);
		}
		pack();
		setLocationRelativeTo(getOwner());
            
	    // Add a list selection listener anonymous instance to JList control:
            // (implementing valueChanged() method)
	                     ListSelectionListener lListener = new ListSelectionListener() {
	                         public void valueChanged(ListSelectionEvent e) {
	                             if (e.getValueIsAdjusting() == false) // it will prevent double firing when  valueChanged() is called
	                             {
	                                 JList list = (JList) e.getSource();
	                                 if (!(list.isSelectionEmpty())) {
	                                     selectionLine = (String) list.getSelectedValue();

	                                     System.out.println("Selected: " + selectionLine);
	                                     
	                                 }
	                             }
	                         }
	                     };

	                     jlstProjectList.addListSelectionListener(lListener);
                
         listFoldersInFolder("C:\\");
	        
		// End of component initialization  
	}
        
        
        
    public static void main(String[] args) {
          
                  // The static utility method invokeLater(Runnable) is intended to execute a new runnable
                  // thread from a Swing application without disturbing the normal sequence of event dispatching
                  // from the GUI.
          
       SwingUtilities.invokeLater(new Runnable() {
                            public void run() {
                                 try {
                                     // Set the look and feel for the current OS (Windows) Scheme and
                                     // all subsequent jFrames will also have the same look and feel
                                     UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                                     SelectProject selectProject = new SelectProject();
                                     selectProject.setLocationRelativeTo(null);
                                     
                                 } catch (Exception e) {
                                     e.printStackTrace();
                                 }
                            }
                        });
                  }  
      

    private void jbtnOpenProject_ActionPerformed(ActionEvent e) {
            System.out.println("Open project Button Clicked");
            if (selectionLine.equals("")){
                    JOptionPane.showMessageDialog(null, "       Select project to load ", "No Selection Made", JOptionPane.WARNING_MESSAGE);
                }
            else{
                    System.out.println("Open project: " + selectionLine);
                    // Creating Child Window Instances:
                    mainScreenMini3 = new MainScreenMini3(this, 0, selectionLine);
                    getChildMainScreenMini3();
                    this.setVisible(false);
                    mainScreenMini3.setVisible(true);  
                }
    }
    
    
    public void listFoldersInFolder(String pathName)
       {
           model.clear();
           File [] paths;
           File file=new File(pathName);
           if(file.isDirectory()){
             paths = file.listFiles();  
                for (int i=0; i<paths.length; i++)
                {
                    if (paths[i].isDirectory()){
                    System.out.println(paths[i].getPath());
                    
                    model.addElement(paths[i].getName());
                    }
                }
           }
       }
    
    // Returning an instance of the child window:
    private MainScreenMini3 getChildMainScreenMini3(){
        return mainScreenMini3;
    }

}

Select allOpen in new window

The mainScreenMini3 JFrame, that has the button:

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Timer;
import java.util.TimerTask;
import javax.swing.*;

public class MainScreenMini3 extends JFrame {
    
    private JLabel jlblTextLabel;
    private JButton jbtnStartTesting;
    private JScrollPane scrollPane1;
    private JList list1;
    
    Timer timer;  // Declare timer for class scope

    private int timerCount;  // Declare here for class scope
    private int timerPeriod = 1;  // Default 1 second period
    private boolean timerRunning = false;
    
    // Declarations needed for child window frame:
            SelectProject parent;
            int num;
    // End of Declarations needed for child window frame
            
            // Name of the selected test inside network test folder
            public String selectedTest = "";
            
    private HourGlassWindow hourGlassWindow;
    private Thread hourGlassThread;
    
	public MainScreenMini3(SelectProject parent, int num, String folderSelected) {  // Constructor for creating JFrame as Child Window 
            
	    this.parent = parent;
            this.num = num;
            
            System.out.println("Selected Folder: " + folderSelected);
            
            // Initialize folder name of test selected:
            this.selectedTest = folderSelected;
            
		initComponents();
                this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                this.setResizable(false);
	}

	private void initComponents() {
		// Component initialization 
		jlblTextLabel = new JLabel();
		jbtnStartTesting = new JButton();
		scrollPane1 = new JScrollPane();
		list1 = new JList();
                
	    // inner class listener for Standard test button:
	           jbtnStartTesting.addActionListener(new ActionListener() {
	               public void actionPerformed(ActionEvent evt) {
	                   jbtnStartTesting_ActionPerformed(evt);
	               }
	           });

		//======== this ========
		Container contentPane = getContentPane();
		contentPane.setLayout(null);

		//---- jlblTextLabel ----
		jlblTextLabel.setText("Not Tested");
		jlblTextLabel.setFont(new Font("Tahoma", Font.BOLD, 22));
		jlblTextLabel.setHorizontalAlignment(SwingConstants.CENTER);
		contentPane.add(jlblTextLabel);
		jlblTextLabel.setBounds(115, 30, 150, 50);

		//---- jbtnStartTesting ----
		jbtnStartTesting.setText("Start Testing");
		jbtnStartTesting.setFont(new Font("Tahoma", Font.PLAIN, 18));
		contentPane.add(jbtnStartTesting);
		jbtnStartTesting.setBounds(115, 75, 150, 65);

		//======== scrollPane1 ========
		{
			scrollPane1.setViewportView(list1);
		}
		contentPane.add(scrollPane1);
		scrollPane1.setBounds(25, 150, 340, scrollPane1.getPreferredSize().height);

		{ // compute preferred size
			Dimension preferredSize = new Dimension();
			for(int i = 0; i < contentPane.getComponentCount(); i++) {
				Rectangle bounds = contentPane.getComponent(i).getBounds();
				preferredSize.width = Math.max(bounds.x + bounds.width, preferredSize.width);
				preferredSize.height = Math.max(bounds.y + bounds.height, preferredSize.height);
			}
			Insets insets = contentPane.getInsets();
			preferredSize.width += insets.right;
			preferredSize.height += insets.bottom;
			contentPane.setMinimumSize(preferredSize);
			contentPane.setPreferredSize(preferredSize);
		}
    
		pack();
		setLocationRelativeTo(getOwner());
		
	}
        
    // Action Listener for  button:
       private void jbtnStartTesting_ActionPerformed(ActionEvent evt) {
           System.out.println("Button Pressed");
           
           timerCount = 0;
                  
                  if (timerRunning == false){
                      timer = new Timer();  // This will start timer (!)
                      timerRunning = true;    // change it to opposite
                      jbtnStartTesting.setText("Stop Test");
                      
                      timer.scheduleAtFixedRate(new LoopTask(),      // Use scheduleAtFixedRate method when time synchronization is more important                         
                                    0,        //initial delay
                                   timerPeriod * 1000);  //subsequent rate (milliseconds)  
                      
                  }
                  else
                  {
                      timerRunning = false;  // change it to opposite
                      jbtnStartTesting.setText("Start Test");
                      timer.cancel(); // Stop timer
                     
                      // ????????????????????????????????????????????????????
                      // Interrupt the thread to generate an exception in the
                      // HourGlassWindow class instance, never works:
                      hourGlassThread.interrupt();
                      hourGlassWindow = null;
                      
                      timerCount = 0;
                      
                      // ?????????????????????????????????????????????????????
                      // This will never update the screen:
                      jlblTextLabel.setText("<html><font color = red>DONE</font></html>");
                      
                      System.out.println("Timer Stopped.");  // This will show up
                       
                  }
           
           // Create HourGlassWindow instance
           hourGlassWindow = new HourGlassWindow(this);
           hourGlassThread = new Thread(hourGlassWindow);
           hourGlassThread.start();
           hourGlassWindow.setAlwaysOnTop(true);
           hourGlassWindow.setSize(134,142);
            
           // Set the location of the hourglass relative to the CasconMainScreen
           // location on the screen:
           Point pointOfLocation = this.getLocationOnScreen();
           pointOfLocation.setLocation(pointOfLocation.getX()+210,pointOfLocation.getY()+207);
           hourGlassWindow.setLocation(pointOfLocation); 
           hourGlassWindow.setVisible(true);
           
           jlblTextLabel.setText("<html><font color = black>TESTING</font></html>");
           
       }
       
    // LoopTask is an inner class, implementing TimerTask class run() method:
           class LoopTask extends TimerTask {

               public void run() {
                       System.out.println("Run timed method");
                       timerCount++;
                       System.out.println(Integer.toString(timerCount));
                   }
               }   
       
}

Select allOpen in new window

And the hourglass window:

import java.awt.*;
import javax.swing.*;

public class HourGlassWindow extends JWindow implements Runnable{
    
    private Icon iconImage = new ImageIcon(getClass().getResource("icons/HourGlass1.gif"));
    private JLabel jlblHourGlassImage;
    private MainScreenMini3 parent;
    
    private HourGlassWindow hourGlassWindow; 

	public HourGlassWindow(MainScreenMini3 parent) {
		initComponents();
	}

	private void initComponents() {
		jlblHourGlassImage = new JLabel();

		//======== this ========
		Container contentPane = getContentPane();
		contentPane.setLayout(null);

		//---- jlblHourGlassImage ----
		jlblHourGlassImage= new JLabel(iconImage, JLabel.CENTER); // Creating  the jLabel for the image
		jlblHourGlassImage.setHorizontalAlignment(SwingConstants.CENTER);
		contentPane.add(jlblHourGlassImage);
		jlblHourGlassImage.setBounds(10, 10, 105, 100);

		{ // compute preferred size
			Dimension preferredSize = new Dimension();
			for(int i = 0; i < contentPane.getComponentCount(); i++) {
				Rectangle bounds = contentPane.getComponent(i).getBounds();
				preferredSize.width = Math.max(bounds.x + bounds.width, preferredSize.width);
				preferredSize.height = Math.max(bounds.y + bounds.height, preferredSize.height);
			}
			Insets insets = contentPane.getInsets();
			preferredSize.width += insets.right;
			preferredSize.height += insets.bottom;
			contentPane.setMinimumSize(preferredSize);
			contentPane.setPreferredSize(preferredSize);
		}
		pack();
		setLocationRelativeTo(getOwner());
		// JFormDesigner - End of component initialization  //GEN-END:initComponents
	}
    
        
    public void run(){
        try{
            hourGlassWindow = new HourGlassWindow(parent);
            
        }
        
     
     // Cannot get this to compile:   ?????????????????????
  /*      catch(InterruptedException e){
            System.err.println();
        }
*/
    
        catch(Exception e){
            System.err.println();
             hourGlassWindow.dispose();  // Not Working ?????
             hourGlassWindow = null;   // Not Working ?????
        }
    }

}

Select allOpen in new window

And finally, I need to give you the animated GIF image for the hourglass, as an attached file.

What am I doing wrong here?

Thanks.
HourGlass1.gif