In this segment of tutorial we will learn about the wait and notifyAll methods of the Thread.Then We will create an example which is notifying all the threads at a time.

• Wait notifyAll both are the methods of the object class.
• notify is used to notify only the first waiting thread.
• notifyAll notifies all the thread to resume their lock

Java Thread Wait Notifyall Example

class passenger extends Thread {
	train tr;

	public passenger(train trn) {
		tr = trn;
	}

	public void run() {
		synchronized (tr) {
			try {
				System.out.println("Waiting for train...");
				tr.wait();
			} catch (InterruptedException e) {
			}
			System.out.println("Total is: " + tr.total);
		}
	}

	public static void main(String[] args) {
		train mytrain = new train();
		new passenger(mytrain).start();
		new passenger(mytrain).start();
		new passenger(mytrain).start();
		mytrain.start();
	}
}

class train extends Thread {
	int total;

	public void run() {
		synchronized (this) {
			for (int i = 0; i < 100; i++) {
				total += i;
			}
			notifyAll();
		}
	}
}

Output

Waiting for train... Waiting for train... Waiting for train... Total is: 4950 Total is: 4950 Total is: 4950

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