From where are you calling notifyAll()? Can you post your code? The error you are getting means that the current thread is not the owner of the object's monitor. Only one thread at a time can own an object's monitor.There are three ways a thread becomes owner of the object's monitor: � By executing a synchronized instance method of that object. � By executing the body of a synchronized statement that synchronizes on the object. � For objects of type Class, by executing a synchronized static method of that class. Hope this helps.
Snigdha<br />Sun Certified Programmer for the Java™ 2 Platform