Collections and Generics - SCJP Sun Certified Programmer for Java Platform SE6 - page 439

12. list.add(“OH”);
13. list.add(“CO”);
14. list.add(“NE”);
15. list.add(“NJ”);
16. String state = list.get(2);
17. System.out.println(state);
18. if(list.contains(“CO”)) {
19. System.out.println(list.indexOf(“CO”));
20. }
21. Iterator<String> iter = list.iterator();
22. while(iter.hasNext()) {
23. System.out.println(iter.next());
24. }
25. list.clear();
26. System.out.println(list.size());
The sequence of events for the previous statements is as follows:
1. Lines 12-15 add four strings to list .
2. Line 16 sets state to the element at index 2 , which is the third element, “NE“ . Because
of generics, there is no need to cast the return value of get to a String .
3. Line 18 is true and line 19 displays the index of “CO“ , which is 1 .
4. Line 21 returns an Iterator for list , a common technique for iterating through a list.
Using generics, the Iterator declares its elements as String types, which is consistent
with the data types in list .
5. The while loop on lines 22-24 demonstrates the hasNext and next methods of
Iterator , displaying each String in list on a separate line.
6. Line 25 removes all elements from the list, so printing the size on line 26 outputs 0 .
The output of the code is
NE
1
OH
CO
NE
NJ
0