ExecutorService.java

package org.example;

import java.util.concurrent.*;

class TestThread implements Runnable {
  public final String name;
  public final int newcount;
  public final long newtimesleep;

  public TestThread(String name, int newcount, long newtimeSleep) {
    this.name = name;
    this.newcount = newcount;
    this.newtimesleep = newtimeSleep;
  }

  public void run() {
    int sum = 0;

    for (int i=0; i < newcount; i++) {
      sum += i;
    }
    System.out.println(sum);

    try {
      Thread.sleep(newtimesleep);
    } catch (Exception e) {
      e.printStackTrace();
    }
  }
}

public class ExecutorServiceTest {
  private static Future taskTwo = null;
  private static Future taskFour = null;

  public static void main(String[] args) throws InterruptedException, ExecutionException {
    ExecutorService executorService = Executors.newFixedThreadPool(2);

    Runnable taskOne = new TestThread("TasOne", 2, 100);
    executorService.execute(taskOne);

    for (int i=0; i < 2; i++) {
      if (taskTwo == null || taskTwo.isDone() || taskTwo.isCancelled()) {
        taskTwo = executorService.submit(new TestThread("TaskTwo", 4, 200));
      }
      if (taskFour == null || taskFour.isDone() || taskFour.isCancelled()) {
        taskFour = executorService.submit(new TestThread("TaskFour", 8, 400));
      }

      if (taskTwo.get() == null) {
        System.out.println("taskTwo finished successfully");
      } else {
        taskTwo.cancel(true);
      }

      if (taskFour.get() == null) {
        System.out.println("taskFour finished successfully");
      } else {
        taskFour.cancel(true);
      }
    }
    executorService.shutdown();
    executorService.awaitTermination(1, TimeUnit.MINUTES);
  }
}