Swing_Frame_Unable to get output for the animation code

Code :

        public class SimpleAnimation {        	
        	int x=70;
        	int y=70;        	
        	public static void main(String[] args) {        		
        		SimpleAnimation gui = new SimpleAnimation();
        		gui.go();        		
        	}        	
        	public void go()        	
        	{        		
        		System.out.println("go");
        		JFrame frame = new JFrame();
        		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);		
        		MyDrawPanel mdp = new MyDrawPanel();
        		frame.getContentPane().add(mdp);		
        		frame.setSize(300,300);
        		frame.setVisible(true);
        		System.out.println("go");        	
        		for(int i=0;i<130;i++) {        			
        			x++;
        			y++;
              			mdp.repaint();        			
        			System.out.println("go");        			
        			try {
        				Thread.sleep(50);
        			} catch (InterruptedException e) {
        			}
        		}        		        		
        	}        	
        	class MyDrawPanel extends JPanel{        		
        		public void painComponent(Graphics g) {        			
        			g.setColor(Color.white);
        			g.fillRect(0, 0, this.getWidth(), this.getHeight());
              			g.setColor(Color.green);
        			g.fillOval(x, y, 40, 40);
        		}  
        	}
        
        }
   

Query :
The output should be frame filled with white background and round small circle rounds in the a circle. But output is only an empty frame. what would be the missed one? I have used the JPanel extended class as inner class. Could someone help on getting the desired output?

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Swing is single threaded and not thread safe.

This means that you should not block the event dispatching thread with things like Thread.sleep and you should not update the UI or properties the UI relies on from outside of the event dispatching thread.

You should read through Concurrency in Swing which will provide you with more information.

The next issue is you've misspelt painComponent, it should be paintComponent. This is where using @Override to mark methods you thinking you're overriding is important, as it will generate a compiler error if not method exists in the parent classes

import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
public class SimpleAnimation {
int x = 70;
int y = 70;
int tick = 0;
public static void main(String[] args) {
SimpleAnimation gui = new SimpleAnimation();
gui.go();
}
public void go() {
System.out.println("go");
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
MyDrawPanel mdp = new MyDrawPanel();
frame.getContentPane().add(mdp);
frame.setSize(300, 300);
frame.setVisible(true);
System.out.println("go");
Timer timer = new Timer(50, new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
tick++;
if (tick > 129) {
((Timer)e.getSource()).stop();
}
x++;
y++;
mdp.repaint();
}
});
timer.start();
}
class MyDrawPanel extends JPanel {
public MyDrawPanel() {
setBackground(Color.WHITE);
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(Color.green);
g.fillOval(x, y, 40, 40);
}
}
}

Your MyDrawPanel does not override the paintComponent method (you missed a 't'), this should be:

	@Override
public void paintComponent(Graphics g) {

Note that the (optional) @Override annotation yields a compile error in case you have a typo, so it's good practice to add it.