divide by zero

class exe6
{
static void nestry(int a)
{
try
{

if(a==1)
a=a/a-a;
if(a==2)
{
int[] c=new int[100];
c[100]=100;
System.out.println("this wont come");
}
}
catch(Exception e)
{
System.out.println("array index out of range"+e);
}

}



public static void main(String args[])
{
try
{
int a=Integer.parseInt(args[0]);
int b=21/a;
System.out.println(b);
nestry(a);
}
catch(Exception e)
{
System.out.println("divide by zero"+e);
}

}

}