Marcus Syncronization Q

[Win jones]

From Marcus online exam

What will happen if you attempt to compile and run the following code?
public class Master{
    boolean bContinue=false;
    public static void main(String argv[]){
Master m = new Master();
m.go();
    }
    public void go(){
Slave s = new Slave(this);
Thread t1 = new Thread(s);
t1.start();
while(bContinue==false){
}
s.setPrice(200);
    }
}
 
class Slave implements Runnable{
    int iPrice =100;
    Master master;
    Slave(Master m){
master=m;
    }
[B]    synchronized public void setPrice(int iM)[/B]{
iPrice=iM;
    }
 
    synchronized public void run(){
master.bContinue=true;
while(true){
    System.out.println(iPrice);
}
 
    }
}

The Output is : Compilation and repeated output of 100 agree but one of the comments provided is as follows Although bContinue does get set to true, the setPrice call is blocked because setPrice and run are both synchronized - (I am new to java and programming ) but would like to understand where is the slave class referring to the setPrice method , does a system.out.println(iPrice) within the while loop automatically call the setPrice method thereby preventing the method call s.setPrice(200) in the Master class from setting the price???

[Erin Goettl]

I'm surprised that this code even works at all. Shouldn't there be a complier error because the public void run() method is missing? I thought you couldn't add the modifier synchronized to an overriding method.

[Win jones]

Erin, The code does compile (It compiles and gives a constant output of 100)and synchronized is fine

[Erin Goettl]

Ok thanks!

[Mike Gershman]

setPrice() would be called by the go() method in Master, except that execution of go() never gets past t1.start(), which lets run() go into a loop while holding the lock.

[Harsh Singh]

setPrice() would be called by the go() method in Master, except that execution of go() never gets past t1.start(), which lets run() go into a loop while holding the lock.
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The main thread will actually go past t1.start() and the while(bContinue==false) loop but will get stuck at the s.setPrice(200) because thread t1 holds the lock on Slave object 's' while executing run method.