Condition Variables

Condition variables allow threads to wait for certain conditions to be met.

The wait() method makes a thread wait until another thread invokes notify() or notifyAll() on the same object.

public class ConditionExample {


 // Condition variables allow threads to wait for certain conditions to be met.

    // The wait() method makes a thread wait until another thread invokes notify() or notifyAll()

    // on the same object.


 private static final Object lock = new Object();
 private static boolean dataReady = false;


 public static void main(String[] args) throws InterruptedException {
 Thread producer = new Thread(() -> {
 synchronized (lock) {
 dataReady = true;
 lock.notifyAll();

            }

        });


 Thread consumer = new Thread(() -> {
 synchronized (lock) {
 while (!dataReady) {
 try {
 System.out.println("Waiting for data...");
 lock.wait();

                    } catch (InterruptedException e) {
 Thread.currentThread().interrupt();

                    }

                }
 System.out.println("Data is ready!");

            }

        });


 consumer.start();
 Thread.sleep(1000);  // Ensure consumer is waiting
 producer.start();


 producer.join();
 consumer.join();

    }

}

Waiting for data...

Data is ready!