Page: 3
12. Collections and Generics
Q: 09 Given:
11. public static Collection get() {
12. Collection sorted = new LinkedList();
13. sorted.add("B"); sorted.add("C"); sorted.add("A");
14. return sorted;
15. }
16. public static void main(String[] args) {
17. for (Object obj: get()) {
18. System.out.print(obj + ", ");
19. }
20. }
What is the result?
A. A, B, C,
B. B, C, A,
C. Compilation fails.
D. The code runs with no output.
E. An exception is thrown at runtime.
Answer: B Q:10 given
Click the Task button. 
Solution:
- Compilation of the first statement succeeds ,but compilation fails due to an error in the second statement.
- Compilation fails due to an error in the first statement
- Compilation succeeds
4. Compilation succeeds Q: 11 Given:
11. public static Iterator reverse(List list) {
12. Collections.reverse(list);
13. return list.iterator();
14. }
15. public static void main(String[] args) {
16. List list = new ArrayList();
17. list.add("1"); list.add("2"); list.add("3");
18. for (Object obj: reverse(list))
19. System.out.print(obj + ", ");
20. }
What is the result?
A. 3, 2, 1, B. 1, 2, 3,
C. Compilation fails. D. The code runs with no output.
E. An exception is thrown at runtime.
Answer: C Q: 12 Click the Task button. 
============does not compile================
1.m1(listO );
2.m2(listB);
3.m2(listO);
=====compiles and runs with out error=========
1.m1(listA);
2.m1(listB);
3.m2(listA); Q: 13 Given:
1. import java.util.*;
2. public class PQ {
3. public static void main(String[] args) {
4. PriorityQueue<String> pq = new PriorityQueue<String>();
5. pq.add("carrot");
6. pq.add("apple");
7. pq.add("banana");
8. System.out.println(pq.poll() + ":" + pq.peek());
9. }
10. }
What is the result?
A. apple:apple
B. carrot:apple
C. apple:banana
D. banana:apple
E. carrot:carrot
F. carrot:banana
Answer: C
Page: 3
1
2
3
4
5
6
7
8
9
10
11
12
|
