Java window not setting background color?

Question

This is probably a really stupid error but iv'e just started learning the .awt package. I followed a tutorial to the letter, in the video his window's background is red, there are no errors in my code yet it won't change the background color. Thanks for any help!

import java.awt.Color;
import javax.swing.*;
public class Test {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
JFrame f = new JFrame();
f.setVisible(true);
f.setSize(350,350);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setTitle("Window");
f.setBackground(Color.RED);
    }

}

Answer 1

1) JFrame can't do that, you have to change Color for content pane e.g.

JFrame.getContentPane().setBackground(myColor)

2) You need to wrap GUI related code (in main method) to the invokeLater

For example:

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

public class GUI {

    public GUI() {
        JFrame frame = new JFrame();
        frame.setTitle("Test Background");
        frame.setLocation(200, 100);
        frame.setSize(600, 400);
        frame.addWindowListener(new WindowAdapter() {

            @Override
            public void windowClosing(WindowEvent e) {
                System.exit(0);
            }
        });
        frame.getContentPane().setBackground(Color.BLUE);
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        javax.swing.SwingUtilities.invokeLater(new Runnable() {

            public void run() {
                GUI gUI = new GUI();
            }
        });
    }
}

Answer 2

Instead of

f.setBackground(Color.RED);

call

f.getContentPane().setBackground(Color.RED);

The content pane is what is displayed.

As a side note, here's a JFrame tip: you can call f.add(child) and the child will be added to the content pane for you.