Why setBackground method can't set the background of my JPanel?

Question

I am trying to build a simple oval slider program. I gave the window's background color orange, but it's not setting the background as orange, rather a gray background. Moreover the slider can't pass the appropriate value. Becaause when I slide to increase the size of the oval, it turns into a strange shape, distracting from it's original oval shape.

This is my complete code:

package drawoval;

import java.awt.Color;
import javax.swing.JFrame;

public class Drawoval {

    public static void main(String[] args) {

        TheWindows tw=new TheWindows();
        tw.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        tw.setSize(230,280);
        tw.setVisible(true);

    }


}



package drawoval;

import java.awt.*;
import javax.swing.*;

import javax.swing.event.*;

public class TheWindows extends JFrame{
   private JSlider slider;
   private Oval myPanel;


    public TheWindows(){
       super("The title");
       myPanel=new Oval();
       myPanel.setBackground(Color.ORANGE);
       slider=new JSlider(SwingConstants.HORIZONTAL,0, 200,10);
       slider.setMajorTickSpacing(10);
       slider.setPaintTicks(true);
       slider.addChangeListener(
       new ChangeListener(){
           public void stateChanged(ChangeEvent e){
               myPanel.setNewD(slider.getValue());

           }

       }

       );
       add(slider,BorderLayout.SOUTH);
       add(myPanel,BorderLayout.CENTER);

    }



}



package drawoval;

import java.awt.Dimension;
import java.awt.Graphics;
import javax.swing.JPanel;

public class Oval extends JPanel {

    private int d = 10;

    public void paintComponent(Graphics g) {
        super.paintComponents(g);
        g.fillOval(10, 10, d, d);

    }

    public void setNewD(int newD) {
        d = (newD >= 0 ? newD : 10);
        repaint();

    }

    public Dimension getPreferredDim() {

        return new Dimension(200, 280);

    }

    public Dimension getMinSize() {
        return getPreferredDim();

    }

}

Answer 1

Because your calling super.paintComponents(g); and not super.paintComponent(g) ...not the s at the end of the method name...

Also, I'm not sure what you think getPreferredDim and getMinSize will do, but they won't be called by any API within Swing, I think you mean getPreferredSize and getMinimumSize which will be used by the layout manager to make better decisions about how to layout your component