Java-kalender 2

Jeg er gang med at lave et Java-program der undersøger hvilken ugedag en bestemt dato er (uden at bruge diverse indbyggede Calender-funktioner o.lign). Men jeg får nogle fejl med denne kode:

GregorCalculations.java
-----------------------
public class GregorCalculations
{
    static final int[][] monthLengths = {{31,28,31,30,31,30,31,31,30,31,30,31},
                                          {31,29,31,30,31,30,31,31,30,31,30,31}};

    static int leapYear(int year)
    {
        int isLeapYear = 0;

        if(((year % 4 == 0) && (year % 100 != 0)) || (year % 400 == 0))
        {
            isLeapYear = 1;
        }

        return isLeapYear;
    }

    static int days_monthCounter(int month)
    {
        int days_PrevMonths = 0;

        for(int monthCounter = 0; monthCounter < month; monthCounter++)
        {
            days_PrevMonths += monthLengths[leapYear(year)][monthCounter];
        }

        return days_PrevMonths;
    }

    static int days_PrevYears(int year)
    {
        int days_PrevYears = 0;

        for(int yearCounter = 1; yearCounter < year; yearCounter++)
        {
            days_PrevYears += yearCounter * days_monthCounter(monthLengths.length);
        }

        return days_PrevYears;
    }

    static public int daysSince1_jan_1(int year, int month, int day)
    {
        return (day + days_monthCounter(month) + days_PrevYears(year));
    }
}



Gregor.java
-----------
public class Gregor
{
    static public String dayOfWeek(int year, int month, int day) //throws Exception (ikke lavet endnu)
    {
        String[] weekDays = {"Sunday","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday"};

        int weekDayNumber = GregorCalculations.daysSince1_jan_1(year,month,day) % 7;
        String weekDay = weekDays[weekDayNumber];

        return weekDay;
    }
}




GregorTest.java
---------------
class GregorTest
{
    public static void main(String[] args)
    {
        System.out.println(Gregor.dayOfWeek(1,1,1));
        System.out.println(Gregor.dayOfWeek(2003,11,29));
        System.out.println(Gregor.dayOfWeek(2003,11,30));
        System.out.println(Gregor.dayOfWeek(2004,4,1));
        System.out.println(Gregor.dayOfWeek(2004,2,29));
    }
}


Men jeg får denne fejl:

C:\Java>javac Gregor.java
.\GregorCalculations.java:24: cannot resolve symbol
symbol  : variable year
location: class GregorCalculations
                        days_PrevMonths += monthLengths[leapYear(year)][monthCounter];
                                                                ^
1 error

Hvad er der galt og kan det slet ikke passe at den 1. januar år 1 er en mandag?