Java Calendar - Using Swings

I've developed a Java calendar program which is based on Swing concept. Below the screenshot of my program.

This program has two panels, one to hold the combo boxes and other one to hold the labels to display dates/days. I've implemented an ItemListener which will be fired when user chooses a value from the ComboBox. itemStateChanged method invokes my method drawCalendar(), which will take care of removing all the existing elements from the Panel and adding the days and dates based on user selection. By default, the current month's calendar will be displayed.

CalendarDemo.java

/**
 * Java Calendar class
 * @author SANTHOSH REDDY MANDADI
 * @since 25-June-2012
 * @version 1.0
 */

import java.awt.Container;
import java.awt.FlowLayout;
import java.awt.GridLayout;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.util.Date;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingConstants;

public class CalendarDemo extends JFrame implements ItemListener
{
    JPanel p1, p2;
    JComboBox month;
    JComboBox year;
    int days[]={31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
    String weekdays[] = {"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"};
    String months[] = {"January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"};
    public CalendarDemo(String title)
    {
        super();
        setTitle(title);
        p1 = new JPanel();
        //p1.setSize(350, 30);
        //p1.setLayout(new FlowLayout());
        month = new JComboBox();
        for(int i=0;i< months.length;i++)
        {
            month.addItem(months[i]);
        }
        month.addItemListener(this);
        year = new JComboBox();
        for(int i=1980;i<=2099;i++)
        {
            year.addItem(i);
        }
        year.addItemListener(this);
        p1.add(month);
        p1.add(year);
        p2 = new JPanel();
        p2.setLayout(new GridLayout(0,7,5,5));
        Date date = new Date();
        drawCalendar(months[date.getMonth()], (1900+date.getYear()));
        year.setSelectedItem((1900+date.getYear()));
        month.setSelectedItem(months[date.getMonth()]);
        Container c=getContentPane();
        c.setLayout(new FlowLayout());
        add(p1);
        add(p2);
        setVisible(true);
        //setBounds(200, 200, 350, 300);
        setSize(230,220);
        setResizable(false);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
    }
    public static void main(String args[])
    {
        CalendarDemo frame = new CalendarDemo("Calendar");
    }

    @Override
    public void itemStateChanged(ItemEvent e)
    {
        if(e.getStateChange() == ItemEvent.SELECTED)
        {
            drawCalendar((String)month.getSelectedItem(), (Integer)year.getSelectedItem());
        }
    }
    
    public void drawCalendar(String inputMonth, int inputYear)
    {
        p2.removeAll();
        for(int i=0;i< weekdays.length;i++)
        {
            JLabel label = new JLabel(weekdays[i]);
            label.setHorizontalAlignment(SwingConstants.RIGHT);
            p2.add(label);
        }
        Date date = new Date("01-"+inputMonth+"-"+inputYear);
        int noOfDaysInMonth = days[date.getMonth()];
        if(date.getYear()%4==0 && date.getMonth()==1)
        {
            noOfDaysInMonth = 29;
        }

        for(int i=1, day=1;day<=noOfDaysInMonth;i++)
        {
            for(int j=0;j<7;j++)
            {
                if(day==1)
                {
                    if(j==date.getDay())
                    {
                        JLabel label = new JLabel(String.valueOf(day));
                        label.setHorizontalAlignment(SwingConstants.RIGHT);
                        p2.add(label);
                        day++;
                    }
                    else
                    {
                        JLabel label = new JLabel("");
                        p2.add(label);
                    }
                }
                else
                {
                    JLabel label = new JLabel(String.valueOf(day));
                    label.setHorizontalAlignment(SwingConstants.RIGHT);
                    p2.add(label);
                    day++;
                }
                if(day>noOfDaysInMonth)
                {
                    break;
                }
            }
        }
        p2.validate();
        setTitle(inputMonth+", "+inputYear);
    }
}

This has been tested on Java 1.5 and 1.6 versions of Sun Microsystem's Java.
Click here to check out other programs that I've developed.