Thread Prog...

1.
class Job extends Thread {
private int number = 0;
    public void run() {
    synchronized (this) {
        for (int i = 1; i < 1000000; i++) {
            number++;
        }
        notify();
    }
    }
    public int getNumber() {
        return number;
    }
}
public class Test {
    public static void main(String[] args) throws Exception {
        Job thread = new Job();
        thread.start();
        synchronized (thread) {
            thread.wait();
        }
        System.out.println(thread.getNumber());
    }
}
 
2.
class Job extends Thread {
    private int number = 0;
    public void run() {
        for (int i = 1; i < 1000000; i++) {
            number++;
        }
    }
    public int getNumber() {
        return number;
    }
}
public class Test {
    public static void main(String[] args)
    throws InterruptedException {
        Job thread = new Job();
        thread.start();
        synchronized (thread) {
            thread.wait();
        }
        System.out.println(thread.getNumber());
    }
}
 
//Why Notify Not Used in This Second Program...Whithout That How The Thread Is Comming To Runnable State ...

Options Are:
1.It prints 0.
2.It prints 999999.
3.The output is not guaranteed to be any of the above.

In Both The Codes Option 2 is correct...why option 3 is not correct

Source:

http://nikojava.wordpress.com/2008/09/08/scjp-mock-exam-for-threads/

[ November 01, 2008: Message edited by: Thangaraj Raj ]

[ November 01, 2008: Message edited by: Thangaraj Raj ]

[ November 01, 2008: Message edited by: Thangaraj Raj ]
[ November 01, 2008: Message edited by: Thangaraj Raj ]

Thangraj please Quote your source

ok...Ankit Garg...i have edited the source...
please check it...

Hello Thangaraj Raj

In both cases main thread executes wait() on thread object after notify by thread object in case 1 main prints vlue of number
in second case answer is here

http://www.coderanch.com/t/270321/java-programmer-SCJP/certification/Threads

Regards
Ninad

thank you...Ninad Kulkarni...my doubt is cleared...

but before " synchronized (thread) { "
this line gets execute...new thread is moved from runnable to running state...that time the main thread will be in blocked state for ever...if this happens how the 2nd option is possible...
[ November 01, 2008: Message edited by: Thangaraj Raj ]

oh yes, in case 1,if the Job(thread) run first,and after it complete,after that the main thread run,so will the main thread wait forever?

main thread waits forever...

so Anut Walidera ,if the main thread waits forever,then the main thread won't print anything out,so the answer should be "3.The output is not guaranteed to be any of the above."