例題7：

True or False: Readers have methods that can read and return floats and doubles.

A. Ture

B. False

解答：B

點(diǎn)評(píng)： Reader/Writer只處理Unicode字符的輸入輸出。float和double可以通過stream進(jìn)行I/O.

例題8：

What does the following paint() method draw?

1. public void paint(Graphics g) {

2. g.drawString(“Any question”, 10, 0);

3. }

A. The string “Any question?”, with its top-left corner at 10,0

B. A little squiggle coming down from the top of the component.

解答：B

點(diǎn)評(píng)：drawString(String str, int x, int y)方法是使用當(dāng)前的顏色和字符，將str的內(nèi)容顯示出來，并且最左的字符的基線從（x,y）開始。在本題中，y=0，所以基線位于最頂端。我們只能看到下行字母的一部分，即字母‘y’、‘q’的下半部分。

例題9：

What happens when you try to compile and run the following application? Choose all correct options.

1. public class Z {

2. public static void main(String[] args) {

3. new Z();

4. }

5.

6. Z() {

7. Z alias1 = this;

8. Z alias2 = this;

9. synchronized(alias1) {

10. try {

11. alias2.wait();

12. System.out.println(“DONE WAITING”);

13. }

14. catch (InterruptedException e) {

15. System.out.println(“INTERR

UPTED”);

16. }

17. catch (Exception e) {

18. System.out.println(“OTHER EXCEPTION”);

19. }

20. finally {

21. System.out.println

(“FINALLY”);

22. }

23. }

24. System.out.println(“ALL DONE”);

25. }

26. }

A. The application compiles but doesn't print anything.

B. The application compiles and print “DONE WAITING”

C. The application compiles and print “FINALLY”

D. The application compiles and print “ALL DONE”

E. The application compiles and print “INTERRUPTED”

解答：A

點(diǎn)評(píng)：在Java中，每一個(gè)對(duì)象都有鎖。任何時(shí)候，該鎖都至多由一個(gè)線程控制。由于alias1與alias2指向同一對(duì)象Z，在執(zhí)行第11行前，線程擁有對(duì)象Z的鎖。在執(zhí)行完第11行以后，該線程釋放了對(duì)象Z的鎖，進(jìn)入等待池。但此后沒有線程調(diào)用對(duì)象Z的notify()和notifyAll()方法，所以該進(jìn)程一直處于等待狀態(tài)，沒有輸出

相關(guān)鏈接：JAVA認(rèn)證考試報(bào)考指南  考試論壇 考試知道   考試動(dòng)態(tài)

（責(zé)任編輯：fky）

共2頁,當(dāng)前第1頁  第一頁  前一頁  下一頁