How can I save my drawing? (Basic Paint app)

Question

How can I save my drawing like .jpeg .png? I want to capture the image drawn on the panel and save when I will click the save button. I tried buffered image methods but I can't run it. When I search buffered image methods its need extends to JPanel, my code based on JFrame.

The current version of the application:

    import javax.swing.JFrame;
    import javax.swing.JLabel;
    import javax.swing.JButton;
    import javax.swing.JPanel;
    import java.awt.event.MouseMotionListener;
    import java.awt.event.MouseEvent;
    import java.awt.event.ActionListener;
    import java.awt.event.ActionEvent;
    
    import java.awt.Container;
    import java.awt.BorderLayout;
    import java.awt.Graphics;
    import java.awt.Color;
    import java.awt.GridLayout;

    public class Cizim extends JFrame implements MouseMotionListener,ActionListener {
    private int x = -10 , y = -10 ;
    private Color col = Color.BLACK;
    private JLabel mousePos;
    
    public Cizim() {
        final JPanel panel = new JPanel();
        panel.setLayout(new BorderLayout());
        JPanel bottom = new JPanel();
        bottom.setLayout(new BorderLayout());
        mousePos = new JLabel("( , )");
        bottom.add(mousePos, BorderLayout.WEST);
        bottom.setVisible(true);
        //JFrame 
        setTitle("Cizim");
        setSize(800,600);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
    
        JPanel p= new JPanel();
    
        
        p.setLayout(new GridLayout(15,1));
        //Buton Renkleri
        JButton red = new JButton("Kirmizi");
        red.setBackground(Color.RED);
        JButton green = new JButton("Yesil");
        green.setBackground(Color.GREEN);
        JButton magenta = new JButton("Mor");
        magenta.setBackground(Color.MAGENTA);
        JButton cyan = new JButton("Turkuaz");
        cyan.setBackground(Color.CYAN);
        JButton orange = new JButton("Turuncu");
        orange.setBackground(Color.ORANGE);
        JButton yellow = new JButton("Sari");
        yellow.setBackground(Color.YELLOW);
        JButton pink = new JButton("Pembe");
        pink.setBackground(Color.pink);
        JButton blue = new JButton ("Mavi");
        blue.setBackground(new Color (51, 51, 204));
        JButton gray = new JButton("Gri");
        gray.setBackground(Color.GRAY);
        JButton black = new JButton("Siyah");
        black.setBackground(Color.BLACK);
        JButton white = new JButton("Silgi");
        white.setBackground(Color.WHITE);
        
        //
        
        p.add(red);
        p.add(green);
        p.add(magenta);
        p.add(cyan);
        p.add(orange);
        p.add(yellow);
        p.add(pink);
        p.add(blue);
        p.add(gray);
        p.add(black);
        p.add(white);
    
        
        red.addActionListener(this);
        green.addActionListener(this);
        magenta.addActionListener(this);
        cyan.addActionListener(this);
        orange.addActionListener(this);
        yellow.addActionListener(this);
        pink.addActionListener(this);
        blue.addActionListener(this);
        gray.addActionListener(this);
        black.addActionListener(this);
        white.addActionListener(this);  //Beyaz rengi silgi olarak kullandım.
        
        Container c = this.getContentPane();
        c.setLayout(new BorderLayout());
        JLabel instructions = new JLabel("Cizmek icin fareyi hareket ettirin.", JLabel.RIGHT);
        c.add(instructions, BorderLayout.SOUTH);
        c.add(p, BorderLayout.WEST);
        c.addMouseMotionListener(this);
        setVisible(true);
        }
        public void actionPerformed(ActionEvent e) {
        String act = e.getActionCommand();
        if(act.equals("Mavi"))
            col = new Color(51, 51, 204);
        else if(act.equals("Kirmizi"))
            col = Color.RED;
        else if(act.equals("Yesil"))
            col = Color.GREEN;
        else if(act.equals("Mor"))
            col = Color.MAGENTA;
        else if(act.equals("Turkuaz"))
            col = Color.CYAN;
        else if(act.equals("Turuncu"))
            col = Color.ORANGE;
        else if(act.equals("Sari"))
            col = Color.YELLOW;
        else if(act.equals("Pembe"))
            col = Color.PINK;
        else if(act.equals("Gri"))
            col = Color.GRAY;
        else if(act.equals("Siyah"))
            col = Color.BLACK;
        else if(act.equals("Silgi"))
            col = Color.WHITE;
        else//bunlardan biri değilse renk siyah olsun
            col = Color.BLACK;
        
    }
    public void mouseMoved(MouseEvent e) {
    }
    public void mouseDragged(MouseEvent e) {
        x = e.getX(); y= e.getY();
        repaint();// özel parametre ile çağrılan çizim metodu
        
    }
    public void paint(Graphics g) {
        g.setColor(col);
        g.fillRect(x, y, 10, 10);
    }
    
    public static void main (String args[]) {
        Cizim p = new Cizim();
    }
}

Answer 1

Instructions

1. Retrieving the image
2. Creating the file to store the image
3. Saving the retrieved image to the newly created file

Retrieval

Create a BufferedImage.

BufferedImage bi = getMyImage();

File Creation

Create a .png file.

File outputFile = new File("save.png");

Writing Image

Draw your buffered image on your .png file.

ImageIO.write(bi, "png", outputfile);

Complete Code

try {
    BufferedImage bi = getMyImage();
    File outputfile = new File("saved.png");
    ImageIO.write(bi, "png", outputfile);
} catch (IOException e) {
    ...
}

Sources

If you would like further information, read this document: https://docs.oracle.com/javase/tutorial/2d/images/saveimage.html