Beginners Lab Java

import java.util.*;
class calendar1
{
public static void main(String arg[])
{
GregorianCalendar c1 = new GregorianCalendar();
int month = Integer.parseInt(arg[0]);
int year = Integer.parseInt(arg[1]);
month = month-1;
c1.set(year,month,1);
int day = c1.get(Calendar.DAY_OF_WEEK);
System.out.println(day);
int numdays = 0;
switch(c1.get(Calendar.MONTH))
{
case 0:
case 2:
case 4:
case 6:
case 7:
case 9:
case 11:
numdays = 31;
break;
case 1:
if(c1.isLeapYear(c1.get(Calendar.YEAR)))
numdays = 29;
else
numdays = 28;
break;
case 3:
case 5:
case 8:
case 10:
numdays = 30;
break;
default:
System.out.println("ERROR IN MONTH SPECIFICATION");
break;
}
display(day,numdays);
}
static void display(int sday , int tday)
{
int k = 0;
System.out.println(" SUN MON TUE WED THU FRI SAT
");
for(int j = 1;j <= sday-1; j++)
{
System.out.print(" ");
k++;
}
for(int i = 1;i <= tday;i++)
{
if(i < 10)
System.out.print(" "+"0"+i+" ");
else
System.out.print(" "+i+" ");
k++;
if ( k == 7)
{
System.out.println();
k = 0;
}
}
}
}