public static void main(String[] args) {  
   
         Date today = new Date();  
   
         Calendar calendar = Calendar.getInstance();  
         calendar.setTime(today);  
   
         calendar.set(Calendar.DAY_OF_MONTH, 1);  
   
         Date firstDayOfMonth = calendar.getTime();  
   
         DateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");  
         System.out.println("Today             : " + sdf.format(today));  
         System.out.println("First Day of Month: " + sdf.format(firstDayOfMonth));  
     }