When the mouse clicks, Java draws a circle

I'm writing a program that draws a circle when I click the mouse So far I have written the following code

import java.awt.*;
import javax.swing.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import javax.swing.event.*;
import java.awt.geom.*;

public class test extends JFrame implements ActionListener,MouseListener {
    Shape circle = new Ellipse2D.Float(10,10,10);

    public test () {
        setSize(250,150);
        addMouseListener(this);
    }

    public static void main(String[] args) {
        //TODO code application logic here
        java.awt.EventQueue.invokelater(new Runnable() {
              public void run() {
                   test frame = new test();
                   frame.setVisible(true);
              }
        });
    }

    public void actionPerformed(ActionEvent ae) {

    }

    public void drawCircle(int x,int y) {
        Graphics g = this.getGraphics();
        g.drawOval(x,y,x,y);
        g.setColor(Color.BLACK);
        g.fillOval(x,2,2);
    }

    public void mouseClicked(MouseEvent e) {
        drawCircle(e.getX(),e.getY());
        repaint();
    }

    public void mouseExited(MouseEvent e) {

    }

    public void mousePressed(MouseEvent e) {

    }

    public void mouseReleased(MouseEvent e) {

    }

    public void mouseEntered(MouseEvent e) {

    }
}

The code is a 400X400 JFrame. When you click open, a circle will be displayed in half a second. The problem is that when I release the mouse, the circle disappears Why?

Solution

Change the mouse click (...) to:

int x,y;

public void mouseClicked(MouseEvent e) {
    x = e.getX();
    y = e.getY();

    repaint();
}

Covering paint (...):

@Override
public void paint(Graphics g) {
    drawCircle(x,y);
}