Someone

public class Day
{
    private String weekDay;
    private String[] weekDays = {"Sunday", "Monday", "Tuesday",
                                 "Wednesday", "Thursday", "Friday",
                                 "Saturday"};
                                 
    public Day()
    {
        weekDay = "Sunday";
    }

    public Day(String d)
    {
            weekDay = d;
    }
    
    public void print()
    {
        System.out.print(weekDay);
    }

    public String toString()
    {
        return weekDay;
    }

    public String nextDay()
    {
        int i;
        
        for(i = 0; i < 7; i++)
            if(weekDay.equals(weekDays[i]))
                break;
        return weekDays[(i + 1) % 7];
    }

    public String prevDay()
    {
        int i;

        if(weekDay.equals("Sunday"))
            return "Saturday";
        else
        {
            for(i = 0; i < 7; i++)
                if(weekDay.equals(weekDays[i]))
                    break;
            return weekDays[i - 1];
        }
    }

    public void addDays(int nDays)
    {
        int i;
        for(i = 0; i < 7; i++)
            if(weekDay.equals(weekDays[i]))
               break;

          weekDay = weekDays[(i + nDays) % 7];
    }

    public void setDay(String d)
    {
        weekDay = d;
    }

    public String getDay()
    {
        return weekDay;
    }
}