In the given, one thread is producing data and another is consuming it. The two threads "Producer" and "Consumer" share the synchronized methods of the class "Threads". At the time of program execution, the "put( )" method is invoked through the "Producer" class which increments the variable "num" by 1. After producing 1 by the producer, the method "get( )" is invoked by through the "Consumer" class which retrieves the produced number and returns it to the output.

class Threads {
int val;
boolean value = false;
synchronized int get() {
if(!value)
try {
wait();
} catch(Exception e) {
System.out.println(e);
}
System.out.println("Get: " + val);
value = false;
notify();
return val;
}
synchronized void put(int val) {
if(value)
try {
wait();
}catch(Exception e) {
System.out.println(e);
}
this.val = val;
value = true;
System.out.println("Put: " + val);
notify();
}
}
class Producer implements Runnable {
Threads th;
Producer(Threads th) {
this.th = th;
new Thread(this, "Producer").start();
}
public void run() {
int i = 0;
while(i<=50) {
th.put(i++);
}
}
}

class Consumer implements Runnable {
Threads th;
Consumer(Threads th) {
this.th = th;
new Thread(this, "Consumer").start();
}
public void run() {
while(true) {
th.get();
}
}
}
class Example {
public static void main(String args[]) {
Threads th = new Threads();
new Producer(th);
new Consumer(th);
}
}

For more information, visit the following link:

http://www.roseindia.net/java/thread/InterthreadCommunication.shtml