Java synchronized seems ignored
- by viraptor
Hi, I've got the following code, which I expected to deadlock after printing out "Main: pre-sync". But it looks like synchronized doesn't do what I expect it to. What happens here?
import java.util.*;
public class deadtest {
public static class waiter implements Runnable {
Object obj;
public waiter(Object obj) {
this.obj = obj;
}
public void run() {
System.err.println("Thead: pre-sync");
synchronized(obj) {
System.err.println("Thead: pre-wait");
try {
obj.wait();
} catch (Exception e) {
}
System.err.println("Thead: post-wait");
}
System.err.println("Thead: post-sync");
}
}
public static void main(String args[]) {
Object obj = new Object();
System.err.println("Main: pre-spawn");
Thread waiterThread = new Thread(new waiter(obj));
waiterThread.start();
try {
Thread.sleep(1000);
} catch (Exception e) {
}
System.err.println("Main: pre-sync");
synchronized(obj) {
System.err.println("Main: pre-notify");
obj.notify();
System.err.println("Main: post-notify");
}
System.err.println("Main: post-sync");
try {
waiterThread.join();
} catch (Exception e) {
}
}
}
Since both threads synchronize on the created object, I expected the threads to actually block each other. Currently, the code happily notifies the other thread, joins and exits.
