package com.journaldev.threads;

​

import java.util.ArrayList;

import java.util.Date;

import java.util.List;

import java.util.concurrent.Callable;

import java.util.concurrent.ExecutionException;

import java.util.concurrent.ExecutorService;

import java.util.concurrent.Executors;

import java.util.concurrent.Future;

​

public class MyCallable implements Callable<String> {

​

    @Override

    public String call() throws Exception {

        Thread.sleep(1000);

        //return the thread name executing this callable task

        return Thread.currentThread().getName();

    }

    public static void main(String args[]){

        //Get ExecutorService from Executors utility class, thread pool size is 10

        ExecutorService executor = Executors.newFixedThreadPool(10);

        //create a list to hold the Future object associated with Callable

        List<Future<String>> list = new ArrayList<Future<String>>();

        //Create MyCallable instance

        Callable<String> callable = new MyCallable();

        for(int i=0; i< 100; i++){

            //submit Callable tasks to be executed by thread pool

            Future<String> future = executor.submit(callable);

            //add Future to the list, we can get return value using Future

            list.add(future);

        }

        for(Future<String> fut : list){

            try {

                //print the return value of Future, notice the output delay in console

                // because Future.get() waits for task to get completed

                System.out.println(new Date()+ "::"+fut.get());

            } catch (InterruptedException | ExecutionException e) {

                e.printStackTrace();

            }

        }

        //shut down the executor service now

        executor.shutdown();

    }

​

}