jFrame doesn't show the image

Question

So guys I want to use the code I have to set the background of the jFrame without adding anything from another class (like using this code in a jPanel then adding that panel to a jFrame). I wanna do everything in this class. I really have no idea what to do, so I tried this out but this code is not displaying the image!

import java.awt.Graphics;
import java.awt.Image;
import javax.swing.ImageIcon;
import javax.swing.JFrame;

public class panel extends JFrame{
    Image img;

    public void paintComponent(Graphics g){
        super.paintComponents(g);

        g.drawImage(img, 0, 0, getWidth(), getHeight(), null);
        g.dispose();
    }

    public panel(){
        img=new ImageIcon(getClass().getResource("bg_login.jpg")).getImage();
        setExtendedState(JFrame.MAXIMIZED_BOTH);
        pack();
        setVisible(true);
    }


    public static void main(String[] args){
        new panel();
    }
}

Answer 1

there is no paintcomponent() method for jframe as it's not a jcomponent but a container .you can make a panel and overide paintcomponent method then setcontentpane of jframe to that panel

example

public class panel extends JPanel {

    Image img;

    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        if (img != null) {
            g.drawImage(img, 0, 0, getWidth(), getHeight(), null);
        }
        // g.dispose();
    }

    public panel() {
         img=new ImageIcon(getClass().getResource("bg_login.jpg")).getImage();

    }

    public static void main(String[] args) {
        JFrame jFrame = new JFrame();
        jFrame.setExtendedState(JFrame.MAXIMIZED_BOTH);
        panel panel = new panel();
        jFrame.setContentPane(panel);
        jFrame.pack();
        jFrame.setVisible(true);
    }
}