Using wait() and notify() with JavaThreads

For the town hall meeting, the MC allows utterances to be heard by taking them from the podium one at a time.
To implement this, the MC sometimes has to wait until one of the speakers says something. The ability to make a thread wait on some condition is a powerful feature of Java, and we will explore it in this section.
First, we will look at the MC's run() method.
Then, we will look at where the MC waits for something to be said.
Then, we will see how the participants notify them when they have said something.

synchronized is a keyword that is used to get a lock on an object. It is not a method.There are no such methods as lock and release in the Object or Thread classes. However, there is a lock() method in java.util.concurrent.locks.Lock interface. synchronized acquires the lock, Object's wait() is used to wait on object, and Object's notify/notifyAll methods are used to release a lock.

synchronized(myObj){  //acquire a lock on myObj
 obj.wait();          // line 2
}
synchronized(myObj){  // acquire a lock on myObj
 obj.notifyAll();     // line 5
}