JLabel.setBackground(Color.red) not working

Question

Hi, I am using the (JLabel) lblPrmf.setBackground(Color.RED), but the label is not colored. Here is my program:
import java.util.*;
import javax.swing.*; //JFrame and JPanel etc...
import java.awt.*; //BorderLayout and Container etc....
import java.awt.Color;
import java.awt.event.*; //ActionListener og WindowAdapter
public class AllVac extends JFrame
//Define JLabel
private JLabel lblDays;
private JLabel lblAbs;
private JLabel lblPrmf;
//Define JButton
private JButton month;
private JButton back;
private JButton forward;
//Define JPanel
private JPanel south;
private JPanel north;
public AllVac()
// JFrame jf = new JFrame("Vacation for the Stavanger Team ");
Container c = getContentPane();
// c.setTitle("Vacation for the Stavanger Team ");
c.setLayout(new BorderLayout());
c.add(new ShowNorth(), BorderLayout.NORTH);
c.add(new ShowSouth(), BorderLayout.SOUTH);
pack();
setVisible(true);
addWindowListener(new Close());
public static void main(String args[])
AllVac a = new AllVac();
public class ShowNorth extends JPanel
public ShowNorth()
     north = new JPanel(new GridLayout(1, 3));
     month = new JButton("August 2006");
     back = new JButton("<<");
     forward = new JButton(">>");
     north.add(back);
     north.add(month);
     north.add(forward);
     add(north);
public class ShowSouth extends JPanel
public ShowSouth()
     int days = 31;
     south = new JPanel(new GridLayout(16, days+1));
//Arrange the days
for ( int i = 1; i<(days+1); i++)
lblDays = new JLabel(" " + Integer.toString(i));
lblDays.setBorder(BorderFactory.createLineBorder(Color.red));
south.add(lblDays);
add(south, BorderLayout.LINE_START);
//Fill in the names and vacation days
for ( int i = 1; i<(days+1); i++)
lblAbs = new JLabel(" ");
south.add(lblAbs);
add(south, BorderLayout.LINE_START);
for (int j = 0; j<14; j++)
for ( int i = 1; i<days+1; i++)
String v = "v";
lblPrmf = new JLabel(" " + v + " ");
lblPrmf.setBackground(Color.RED);
lblPrmf.setBorder(BorderFactory.createLineBorder(Color.blue));
lblPrmf.setBackground(Color.RED);
lblPrmf.repaint();
south.add(lblPrmf);
add(south);
public class Close extends WindowAdapter
public void windowClosing(WindowEvent c)
System.exit(0);
}

Answer 1

You are building a GUI with Swing components. Why would you ask the question in the general programming forum???? People there may never have built a GUI or heard of Swing.
Concepts of creating GUI components adding then to a GUI, dealing with models, listening to events and responding to the events are all techniques related to GUI programming. Even Swing programming is different from AWT programming in some cases.
So when you topic title says. "I have a problem, with a Swing (JLabel) component", or "How do I change a JTable in a JScrollPane" where do you think the question should be asked. Maybe its just me but I would think the Swing forum is where you would find the experts, or at least people who think they know something about Swing.
Your previous posting on "display a button on a background image" was not very clear. You use an Applet and Panel which are an AWT components. But then you are also using JFrame and JButton which are Swing components. Since you posted the question in the general programming forum, I had no idea whether you where attempting to write an AWT or a Swing application so I ignored the posting.