Quick calendar hack-up for friend

calendar.java

import java.util.Scanner;

public class calendar {

    // initialize static scanned
    public static Scanner input = new Scanner(System.in);

    public static void main(String[] args) {
        int month = getMonth();
        int year = getYear();

        System.out.println();

        printCalendar(month, year);
    }

    // get and validate month input
    public static int getMonth()  {
        int month = 0;
        while ((month < 1) || (month > 12)) {
            System.out.println("Enter month number (1-12):");
            month = input.nextInt();
            if ((month < 1) || (month > 12)) {
                System.out.println("Month must be an int between 1-12!");
            }
        }
        return month;
    }
    // return string name for a month number
    public static String nameMonth(int month) {
        String[] months = {"January",
                           "February",
                           "March",
                           "April",
                           "May",
                           "June",
                           "July",
                           "August",
                           "September",
                           "October",
                           "November",
                           "December"};

        return months[month-1];
    }

    // get and validate year input
    public static int getYear()  {
        int year = 0;
        while ((year < 1901) || (year > 2100)) {
            System.out.println("Enter year (1901-2100): ");
            year = input.nextInt();
            if ((year < 1901) || (year > 2100)) {
                System.out.println("Year must be an int between 1901-2100!");
            }
        }
        return year;
    }

    // calculate new years day
    public static int newYearsDay (int year) {
        return (2 + (year-1901) + (year-1901)/4) % 7;
    }

    // tests for leap year
    public static Boolean isLeapYear (int year) {
        if ((year % 4) == 0) {
            return true;
        }
        return false;
    }

    // returns number of days in month
    public static int daysInMonth (int month, int year) {
        int[] days = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
        // february has 29 days in leap year
        if (isLeapYear(year)) days[1] = 29;
        return days[month-1];
    }

    // calculates first day in month of year
    public static int firstDayMonth (int month, int year) {
        int newYears = newYearsDay (year);

        // sum up the number of days prior to current month
        int daysIntoYear = 0;
        for (int i = 1; i < month; i++) {
            daysIntoYear += daysInMonth(i, year);
        }

        // Letting 0 = Sunday, return the integer offset from 0
        return (daysIntoYear % 7);
    }

    public static void printCalendar(int month, int year) {
        int firstDay = firstDayMonth(month, year);
        int numDays = daysInMonth(month, year);

        // print title
        String title = nameMonth(month) + " " + year;
        System.out.printf ("%16s \n", title);

        // print letter week days
        String[] letterDays = {"S", "M", "Tu", "W", "Th", "F", "S"};
        for (int day = 0; day < letterDays.length; day++) {
            System.out.printf ("%2s ", letterDays[day]);
        }
        System.out.println();

        // prints blanks for first day's offset from sunday
        // spotsFilled keeps track of entries so breaks can be inserted
        int spotsFilled = 0;
        for (int i=0; i < firstDay; i++) {
            System.out.printf ("%2s ", "");
            ++spotsFilled;
        }

        // prints the remaining days in the month
        for (int j=1; j <= numDays; j++) {
            // breaks inserted every 7 days
            if ((spotsFilled % 7) == 0)
                System.out.println();
            System.out.printf ("%2d ", j);
            ++spotsFilled;
        }
    }
}