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Thread wait() and notify()

 
Greenhorn
Posts: 1
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Hello everyone,

I would just like to ask if the following code example in the Sierra Bates SCJP Reviewer below is correct. Is it possible for b.wait() in line 9 to wait forever if the notify() action in line 24 comes first?


1. class ThreadA {
2. public static void main(String [] args) {
3. ThreadB b = new ThreadB();
4. b.start();
5.
6. synchronized(b) {
7. try {
8. System.out.println("Waiting for b to complete...");
9. b.wait();
10. } catch (InterruptedException e) {}
11. System.out.println("Total is: " + b.total);
12. }
13. }
14. }
15.
16. class ThreadB extends Thread {
17. int total;
18.
19. public void run( ) {
20. synchronized(this) {
21. for(int i=0;i<100;i++) {
22. total += i;
23. }
24. notify( );
25. }
26. }
27. }


Thanks in advance.

 
Ranch Hand
Posts: 129
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Yes.

After line no:9, the main thread will wait(In Runnable state) until line no:24 executes or until the run method completes.

The Logic would be Main thread is waiting for threadB to complete the total and in Main thread you are displaying it.

 
Ranch Hand
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To Ayusarap:
I dont think so. In my mind, your code`s result is dynamic. Bug I am not sure about it. Can anyone explain it in detail. Thanks a lot.
 
Ranch Hand
Posts: 433
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try this in between line 4 and 6 of your code :


Most probably(99.99999%) this will clarify Kathy and Bert..!!
 
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