Java开发网 - 请大家帮忙。（想了很久也想不出来的几道题。）

Topic: 请大家帮忙。（想了很久也想不出来的几道题。）

1.请大家帮忙。（想了很久也想不出来的几道题。）

Posted by: jin3shan
Posted on: 2006-08-22 12:27

17 of 20、 Given:
Integer i = new Integer (42);
Long 1 = new Long (42);
Double d = new Double (42.0);
Which two expressions evaluate to True? (Choose Two)

A. (i ==1)
B. (i == d)
C. (d == 1)
D. (i.equals (d))
E. (d.equals (i))
F. (i.equals (42))
正确答案: D,E
注解:

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3 of 20、 1. public class SyncTest{
2. public static void main(String[] args) {
3. final StringBuffer s1= new StringBuffer();
4. final StringBuffer s2= new StringBuffer();
5. new Thread () {
6. public void run() {
7. synchronized(s1) {
8. s2.append(“A”);
9. synchronized(s2) {
10. s2.append(“B”);
11. System.out.print(s1);
12. System.out.print(s2);
13. }
14. }
15. }
16. }.start();
17. new Thread() {
18. public void run() {
19. synchronized(s2) { // synchronized
20. s2.append(“C”);
21. synchronized(s1) {
22. s1.append(“D”);
23. System.out.print(s2);
24. System.out.print(s1);
25. }
26. }
27. }
28. }.start();
29. }
30. }
Which two statements are true? (Choose Two)

A. The program prints “ABBCAD”
B. The program prints “CDDACB”
C. The program prints “ADCBADBC”
D. The output is a non-deterministic point because of a possible deadlock condition.
E. The output is dependent on the threading model of the system the program is running on.
正确答案: D,B
注解:
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19 of 20、 Which two are equivalent? (Choose Two)

A. 3/2
B. 3<2
C. 3*4
D. 3<<2
E. 3*2^2
F. 3<<<2
正确答案: C,D
注解: