multidimentional matrix of a calendar, where days can contain a value

public class Calendar
{
  private int[][] days;
  public Calendar(int year, int month)
  {
    int[] daysInMonth = new int[] {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
    int numDaysInMonth = daysInMonth[month];
    days = new int[numDaysInMonth][];
    for (int i = 0; i < numDaysInMonth; i++)
    {
      days[i] = new int[24];
    }
  }
}