What is the awaitTermination method of executor service in Java?

The `awaitTermination` method

The awaitTermination method of ExecutorService in Java is used to wait for all the tasks submitted to the service to complete execution:

After the shutdown of the service was initiated
The wait time for the termination of the service is over
The current thread of execution is interrupted

The method takes a timeout parameter that indicates the maximum time to wait for all the tasks submitted to finish.

Syntax

boolean awaitTermination(long timeout, TimeUnit unit)

Parameters

long timeout: This is the maximum time to wait.
TimeUnit unit: This is the unit of time of the timeout argument.

Return value

This method returns true if the executor service was terminated or returns false if the wait time elapsed before termination.

Code

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
public class Main {
    public static void main(String[] args) throws InterruptedException {
        ExecutorService singleThreadExecutor = Executors.newSingleThreadExecutor();
        singleThreadExecutor.submit(() -> System.out.println("Hello Educative"));
        if(!singleThreadExecutor.isTerminated()){
            singleThreadExecutor.shutdown();
            if(singleThreadExecutor.awaitTermination(1, TimeUnit.SECONDS)) System.out.println("Executor service terminated successfully.");
            else System.out.println("Executor service termination unsuccessful.");
        }
    }
}

Explanation

Lines 1 to 3: We import the relevant classes.
Line 8: We define a single-threaded executor service called singleThreadExecutor.
Line 9: We submit a task to the singleThreadExecutor that prints a string.
Lines 10-15: We check whether the singleThreadExecutor is terminated. If it’s not yet terminated, the shutdown method is invoked on the service. Finally, we wait for the termination of the service for one second using the awaitTermination method. Depending on the value returned by the awaitTermination method, we print whether the service termination was successful or unsuccessful.