Panel Example

import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
import java.applet.Applet;
class Combo extends JPanel
{
JComboBox com;
String str[]={"Blue","Red","Green","Yellow"};
public Combo()
{
com=new JComboBox(str);
add(com);
}

}
public class panels1 extends JFrame implements ItemListener
{
Combo panel1,panel2,panel3,panel4;
JPanel panel;
public panels1()
{
super("Hello");
setVisible(true);
setSize(300,300);
panel=new JPanel();
panel1=new Combo();
panel2=new Combo();
panel3=new Combo();
panel4=new Combo();
panel.setLayout(new GridLayout(2,2));
panel1.setBackground(Color.red);
panel2.setBackground(Color.blue);
panel3.setBackground(Color.cyan);
panel4.setBackground(Color.pink);

panel.add(panel1);
panel.add(panel2);
panel.add(panel3);
panel.add(panel4);
panel1.com.addItemListener(this);
panel2.com.addItemListener(this);
panel3.com.addItemListener(this);
panel4.com.addItemListener(this);
getContentPane().add(panel);
}
public void itemStateChanged(ItemEvent e)
{
if((panel1.com.getSelectedItem().toString()).compareTo("Blue")==0)
{
panel1.setBackground(Color.blue);
}
if((panel2.com.getSelectedItem().toString()).compareTo("Red")==0)
{
panel2.setBackground(Color.red);
}
if((panel3.com.getSelectedItem().toString()).compareTo("Green")==0)
{
panel3.setBackground(Color.green);
}
if((panel4.com.getSelectedItem().toString()).compareTo("Yellow")==0)
{
panel4.setBackground(Color.yellow);
}
}
public static void main(String rags[])
{
new panels1();
}
}
/**/