ExecutorService with newFixedThreadPool example


The Executor Framework provides different types of executors. Some of them are ..

  • SingleThreadExecutor
  • FixedThreadPool(n)
  • CachedThreadPool
  • ScheduledExecutor

Java ExecutorService is an interface in java. It allow in maintaining the thread pool and assign the tasks. Threads execute asynchronously.


package com.threads.example;


import java.util.ArrayList;

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;



/**


this is just name of the class. we are using the Callable interface for creating the task



*/


public class CallableExample {


public static void main(String[] args) throws InterruptedException, ExecutionException {



/**

Getting the number of cpu core and creating the thread pool according to

cpu count

*/

int c = Runtime.getRuntime().availableProcessors();

ExecutorService service = Executors.newFixedThreadPool(c);




List <Future> listFuture = new ArrayList<Future>();

for(int x =0; x <10; x++) {

Future<Emp> future = service.submit(new Task());

listFuture.add(future);

}


//other operations

Future<Emp> future =null;

for(int x =0; x <10; x++) {

future = listFuture.get(x);

Emp result = future.get();

System.out.println( " future result return : " + result);

}

service.shutdown();

}

}


/**

Callable return the Emp object

*/


class Emp {

String name;

int age;

public static int var;

public Emp() {

super();

}

public Emp(String name, int age) {

super();

this.name = name;

this.age = age;

}

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public int getAge() {

return age;

}

public void setAge(int age) {

this.age = age;

}


@Override

public String toString() {

return "Emp [name=" + name + ", age=" + age + "]";

}

}


/**

implementing the callable interface

*/


class Task implements Callable<Emp> {


@Override

public Emp call() throws Exception {

Thread.sleep(1000);

return new Emp(Thread.currentThread().getName() , Emp.var++);

}

}

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