試題詳解

1. public class TestFive{ 

2. private int x；

 3. public void foo(){

 4. int current = x； 

5. x = current + 1；

 6. }

 7. public void go(){ 

8. for(int i=0； i＜5； i++){ 

9. new Thread(){ 

10. public void run(){

 11. foo()； 

12. System.out.print(x + ", ")；

 13. }}.start()； 

14. }}

 Which two changes, taken together, would guarantee the output: 1, 2, 3, 4, 5, ? (Choose two.)
(A) move the line 12 print statement into the foo() method
(B) change line 7 to public synchronized void go(){
(C) change the variable declaration on line 2 to private volatile int x；
(D) wrap the code inside the foo() method with a synchronized(this) block
(E) wrap the for loop code inside the go() method with a synchronized block synchronized(this){//for loop code here}