Java ThreadPoolExecutor isTerminated() Method

The isTerminated() method of ThreadPoolExecutor class returns true if all the tasks have been completed following shut down. Here, we must notice that isTerminated() never returns true unless either shut down or shutdownNow was called first.

Syntax

Parameters

No parameter is passed.

Return

True if all the tasks have been completed following shut down

Throw

Does not throw the exception.

Example 1

import java.util.concurrent.Executors;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import java.lang.Thread;
public class ThreadPoolExecutorisTerminatedExample1   {
            public static void main(final String[] arguments) throws InterruptedException {
                     ThreadPoolExecutor executor = (ThreadPoolExecutor)Executors.newCachedThreadPool();
                     executor.submit(new Task());
                     executor.submit(new Task());
                     executor.shutdown();
                     System.out.println("get Task count after:"+ executor.getTaskCount());
                     System.out.println(" Is Executor is Terminated :"+ executor.isTerminated());
               }  

      static class Task implements Runnable {
      @Override
      public void run() {
              try {
                     Long duration = (long) (Math.random() * 5);
                     System.out.println("Running Thread Name: " + Thread.currentThread().getName());
                     TimeUnit.SECONDS.sleep(duration);
                     System.out.println("Completed Thread Name: " +Thread.currentThread().getName());
                   } catch (InterruptedException e) {  }
                   }
                                   }
}

Test it Now

Output:

get Task count after:2
 Is Executor is Terminated :false
Running Thread Name: pool-1-thread-2
Running Thread Name: pool-1-thread-1
Completed Thread Name: pool-1-thread-2
Completed Thread Name: pool-1-thread-1

Example 2

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.ThreadPoolExecutor;
import java.lang.Thread;
import java.util.logging.Level;
import java.util.logging.Logger;


public class ThreadPoolExecutorisTerminatedExample2 {
     public static void main(String[] args) {
                 Work31 task1 = new Work31("t1");    
                 System.out.println("Starting threads");
                 ThreadPoolExecutor tExecutor = (ThreadPoolExecutor) Executors.newCachedThreadPool();
                 System.out.println("  Maximum pool size: "+ tExecutor.getMaximumPoolSize());
                 System.out.println("get Task count before:"+ tExecutor.getTaskCount());
                 tExecutor.submit(task1); 
                 tExecutor.execute(task1); // start task1
                 System.out.println("get Task count after:"+ tExecutor.getTaskCount());
                 tExecutor.shutdown(); // shutdown worker threads
                 System.out.println(" Is Executor is Terminated :"+ tExecutor.isTerminated());
                 System.out.println("Threads started, main ends\n");
         }
}

 class Work31 implements Runnable {
 
 private final String threadName;

  public Work31(String threadName) {
    this.threadName = threadName;
   }
  
  @Override
  public void run() {
      for(int i=4 ; i<=9;i++)
      {
          if(i==5)
          {
              System.out.println("i=" +i);
              }
          }
          
      }
}

Test it Now

Output:

Starting threads
  Maximum pool size: 2147483647
get Task count before:0
get Task count after:2
 Is Executor is Terminated :false
Threads started, main ends

i=5
i=5

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