1 public class UnsafeDemo
2 {
3 public static void main(String[] args)
4 {
5 // Here, we use the linked list class from Chapter 16
6 LinkedList numbers = new LinkedList();
7 numbers.addFirst(1);
8 numbers.addFirst(2);
9 numbers.addFirst(3);
10 print(numbers);
11 System.out.println("Sum: " + sum(numbers));
12 numbers.addFirst("4"); // No error message
13 print(numbers); // No error
14 System.out.println("Sum: " + sum(numbers));
15 // ClassCastException
16 }
17
18 public static void print(LinkedList lst)
19 {
20 ListIterator iter = lst.listIterator();
21 while (iter.hasNext())
22 {
23 System.out.print(iter.next() + " ");
24 }
25 System.out.println();
26 }
27
28 public static int sum(LinkedList lst)
29 {
30 int sum = 0;
31 ListIterator iter = lst.listIterator();
32 while (iter.hasNext())
33 {
34 sum = sum + (Integer) iter.next();
35 }
36 return sum;
37 }
38 }