Calender

/*This code accepts the year and month from the user and displays the calender of the month of the year entered by the user.
contributed by Rishi*/
import java.util.*;

public class MonthCalendar {

     public static void main(String[] args) {
     Scanner scan = new Scanner (System.in);
     System.out.print("Enter year : ");
     int year = scan.nextInt();
     System.out.print("Enter month : ");
     int month = scan.nextInt();

      if (month < 1 || month > 12)
          System.out.println("Wrong input!");
      else
          printMonth(year, month);
   }
     static void printMonth(int year, int month) {
          printMonthTitle(year, month);
          printMonthBody(year, month);
    }
      static void printMonthTitle(int year, int month) {
          System.out.println("         " + getMonthName(month) + " " + year);
          System.out.println(" Sun Mon Tue Wed Thu Fri Sat");
    }
    static String getMonthName(int month) {
      String monthName = null;
      switch (month) {
        case 1: monthName = "January"; break;
        case 2: monthName = "February"; break;
        case 3: monthName = "March"; break;
        case 4: monthName = "April"; break;
        case 5: monthName = "May"; break;
        case 6: monthName = "June"; break;
        case 7: monthName = "July"; break;
        case 8: monthName = "August"; break;
        case 9: monthName = "September"; break;
        case 10: monthName = "October"; break;
        case 11: monthName = "November"; break;
        case 12: monthName = "December";
      }
      return monthName;
    }
    static void printMonthBody(int year, int month) {
      int startDay = getStartDay(year, month);
      int numberOfDaysInMonth = getNumberOfDaysInMonth(year, month);
      int i = 0;
      for (i = 0; i < startDay; i++)
        System.out.print("    ");
      for (i = 1; i <= numberOfDaysInMonth; i++) {
        if (i < 10)
          System.out.print("   " + i);
        else
          System.out.print("  " + i);
        if ((i + startDay) % 7 == 0)
          System.out.println();
      }
      System.out.println();
    }
   static int getStartDay(int year, int month) {
      int startDay1800 = 3;
      int totalNumberOfDays = getTotalNumberOfDays(year, month);
      return (totalNumberOfDays + startDay1800) % 7;
    }
    static int getTotalNumberOfDays(int year, int month) {
     int total = 0;
     for (int i = 1800; i < year; i++)
     if (isLeapYear(i))
        total = total + 366;
      else
        total = total + 365;
      for (int i = 1; i < month; i++)
        total = total + getNumberOfDaysInMonth(year, i);
      return total;
    }
    static int getNumberOfDaysInMonth(int year, int month) {
      if (month == 1 || month == 3 || month == 5 || month == 7 || month == 8 || month == 10 || month == 12)
        return 31;
      if (month == 4 || month == 6 || month == 9 || month == 11)
        return 30;
      if (month == 2) return isLeapYear(year) ? 29 : 28;
      return 0; 
    }
    static boolean isLeapYear(int year) {
      return year % 400 == 0 || (year % 4 == 0 && year % 100 != 0);
    }
}