problem in getPosition and setPosition......

[Punit Jain]

Cpoint.java

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class Cpoint extends JPanel implements Runnable{
	int x =400;
	int y = 25;
	int dx = 4;
	int dy = 1;
	int radius = 20;
	
	Cpoint()
	{
		Thread thread = new Thread(this);
		thread.start();
	}
	/*public void setPosition(int x)
	{	
		this.x = x;
	}*/
	public int getPosition()
	{
		return x;
	}
	public void run() {
		// TODO Auto-generated method stub
		while(true)
		{
			if(x+dx>this.getWidth()-radius)
			{
			x = this.getWidth()-radius-1;
			dx = -dx;
			}
			else if(x + dx < 0+radius)
			{
				x = 0+radius;
				dx = -dx;
			}
			else
			{
			x+=dx;
			}
			if(y+dy>this.getHeight()-radius)
			{
			y = this.getHeight()-radius-1;
			dy = -dy;
			}
			else if(y + dy < 0+radius)
			{
			y = 0+radius;
			dy = -dy;
			}
			else
			{
			y+=dy;
			}
			x+=dx;
			repaint();
			try {
				Thread.sleep(17);
			} catch (InterruptedException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
	}
	
	public void paintComponent(Graphics g)
	{
		super.paintComponent(g);
		g.setColor(Color.BLUE);
		g.fillOval(x-radius, y-radius, radius*2,radius*2);
		System.out.println(this.getPosition());
	}
	
}

Main.java

import javax.swing.JFrame;
public class Main {
	public static void main(String args[])
	{
		JFrame frame = new JFrame();
		frame.setVisible(true);
		frame.setSize(800,600);
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		Cpoint point = new Cpoint();
		frame.add(point);
	}
}

code is working, my question is why and how we use getPosition() and setPosition(), however

System.out.println(this.getPosition()); this can be done using this also System.out.println(x);

and also is something wrong i m doing here to implement these two methods..?