How can I calculate a day of a week?

Question

I want to calculate a day of a week.But I always getting ArraysOutOfBoundException.Here's my code:
import java.util.*;
import javax.swing.*;
class daydate{
     public static void main(String args[])throws Exception
     String arr[]={
          "satarday","sunday","monday","tuesday","wednesday","thursday","friday"
String output="",op="",m,m1,m2;
     Calendar calendar=Calendar.getInstance();
     int i=calendar.get(Calendar.DAY_OF_WEEK);
/*if(i>6)
     i=i-7;*/
// System.out.println(i);
     output+="\ntoday is :"+arr[i]+"\n";
     JOptionPane.showMessageDialog(null,output,"day",JOptionPane.INFORMATION_MESSAGE);
     m=JOptionPane.showInputDialog("Enter year.");
     int n=Integer.parseInt(m);
m1=JOptionPane.showInputDialog("Enter month.");
     int n1=Integer.parseInt(m1);
     m2=JOptionPane.showInputDialog("Enter date.");
     int n2=Integer.parseInt(m2);
calendar.set(n,n1,n2);
int j=calendar.get(Calendar.DAY_OF_WEEK);
/*if(j>6)
j=j-7;*/
//System.out.println(j);
op+="\nthat day is/was :"+arr[j]+"\n";
     JOptionPane.showMessageDialog(null,op,"day",JOptionPane.INFORMATION_MESSAGE);
System.exit(0);
the error is:
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 7
     at CalculateDay.main(CalculateDay.java:28)
I wonder using calendar.get(Calendar.DAY_OF_WEEK) makes the value of i=7;But my array's highest value is 6.That's why I always get the above error.
How can I solve that?

Answer 1

I think the DAY_OF_WEEK is working from 1 to 7, and
Saturday, on my PC (UK GregorianCalendar) is 7. Your
array is based 0, and only work from (0-6).
Either subtract 1 from the value DAY_OF_WEEK, or add
a blank item at the beginning of the list.
Better, I think is used the built-in capability using
public String getDate(String format){
Calendar c = new GregorianCalendar();
Date d = cal.getTime();
DateFormat df = new SimpleDateFormat(format);
return df.format(d);
You can then call the getDate() with various formats
ie.
getDate("EEE") alone to get "Wed, Thur" .. etc
getDate("dd/MM/yyyy HH:mm:ss") to get the current
Date and time in that format.
Hope it helps.Thanks William for your valuable help.Anyway,you wrote,
Date d=cal.getTime();
Is it cal or c?