variable not getting updated as expected in Java - javac

Question

I am learning Java and have encountered an unexpected problem:
variable i is getting updated in mouse listener but updated value is not getting passed back to main program. But if I uncomment Thread.sleep(1) block everything is back to normal.
Here is the program:
import java.awt.*;
import java.awt.event.*;
public class MouseEventDemo extends Frame
implements MouseListener {
String msg = "";
int mouseX = 0, mouseY = 0; // coordinates of mouse
static int i=0;//State variable
public MouseEventDemo()
{
addMouseListener(this);
addWindowListener(new MyWindowAdapter());
}
// Handle mouse clicked.
public void mouseClicked(MouseEvent me)
{
i=1;
msg = "Click received. i= "+i;
mouseX = me.getX();
mouseY = me.getY();
repaint();
}
public void mouseMoved(MouseEvent me)
{
}
public void mouseDragged(MouseEvent me)
{
}
public void mouseExited(MouseEvent me)
{
}
public void mouseEntered(MouseEvent me)
{
}
public void mouseReleased(MouseEvent me)
{
}
public void mousePressed(MouseEvent me)
{
}
// Display msg in the window at current X,Y location.
public void paint(Graphics g)
{
g.drawString(msg, mouseX, mouseY);
}
public static void main(String[] args)
{
MouseEventDemo appwin = new MouseEventDemo();
appwin.setSize(new Dimension(300, 300));
appwin.setTitle("MouseEventDemo");
appwin.setVisible(true);
while (true)
{
if(i==1)
{
System.out.println("Value of i is: "+i);
i=0;
}
/*
try
{
Thread.sleep(1);
}
catch(Exception e)
{
System.out.println(e);
};
*/
}
}
}
class MyWindowAdapter extends WindowAdapter
{
public void windowClosing(WindowEvent we)
{
System.exit(0);
}
}
This program behaves not like I have expected, but with Thread.sleep(1) it changes it behaviour