Subtracting two dates in Java

All those pupil who are tired of searching the web for subtracting two dates, here is a simple logic
first find the difference to millilseconds
divide milliseconds to date 


1.convert milliseconds to seconds
2.seconds to minutes
3.minutes to24hours
4.divide difference in milliseconds with above multiple


public class DateSubtraction {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) throws ParseException {
               long diffInMillisec=0;
                long diffInDays=0;
               Calendar firstDate =null;
               Calendar secondDate =null;
                try{
                         // Create two calendars instances
                         firstDate = Calendar.getInstance();
                         secondDate = Calendar.getInstance();
                     
                        //Set the dates
                        firstDate.set(2009, 8, 28);      
                        secondDate.set(2009, 8, 18);

                        // Get the difference between two dates in milliseconds  
                       diffInMillisec = firstDate.getTimeInMillis() - secondDate.getTimeInMillis();    

                       // Get difference between two dates in days
                       diffInDays = diffInMillisec / (24 * 60 * 60 * 1000);      

                       System.out.println("Difference:"+diffInDays);
                     
                    }catch(Exception ex)
                    {
                                ex.printStackTrace();
                     }
            }

       }