How to check if the executor service is terminated

Overview

The isTerminated method of the ExecutorService in Java is used to check whether the executor service is terminated or not.

Syntax

boolean isTerminated();

Parameters

This method has no parameters.

Return value

This method returns true if the executor service is terminated. Otherwise, returns false. The method returns true only after the shutdown or shutdownNow methods are called.

Code

Let’s look at the code below:

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();
            singleThreadExecutor.awaitTermination(1, TimeUnit.SECONDS);
        }
        System.out.println("Executor service terminated - " + singleThreadExecutor.isTerminated());
    }
}

Explanation

  • Lines 1 to 3: We import the relevant classes.

  • Line 8: We call a single-threaded executor service, and singleThreadExecutor is defined.

  • Line 9: We submit a task to the singleThreadExecutor that prints a string.

  • Lines 10 to 13: 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.

  • Line 14: We again check if the service is terminated.

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