Java ThreadPoolExecutor remove() Method

The remove() method of ThreadPoolExecutor class removes this task from the executor's internal queue if it is present, thus causing it not to be run if it has not already started.

Syntax

Parameters

Task - the task to remove

Return

The true if the task was removed

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 ThreadPoolExecutorremoveExample1     {
            public static void main(final String[] arguments) throws InterruptedException {
                     ThreadPoolExecutor executor = (ThreadPoolExecutor)Executors.newCachedThreadPool();
                     executor.submit(new Task());
                     executor.submit(new Task());
                     executor.remove(new Task());
                     executor.shutdown();
                     
               }  
      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:

Running Thread Name: pool-1-thread-2
Running Thread Name: pool-1-thread-1
Completed Thread Name: pool-1-thread-1
Completed Thread Name: pool-1-thread-2

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 ThreadPoolExecutorremoveExample2 {
     public static void main(String[] args) {
                 Workkk task1 = new Workkk("t1");    
                 System.out.println("Starting threads");
                 ThreadPoolExecutor tExecutor = (ThreadPoolExecutor) Executors.newCachedThreadPool();
                 tExecutor.submit(task1); 
                 tExecutor.execute(task1); // start task1
                 tExecutor.remove(task1);
                 tExecutor.shutdown(); // shutdown worker threads
         }
}

  class Workkk implements Runnable {
 private final String threadName;

  public Workkk(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: