Save up to 80 % on our PHP e-learning courses. Only this week!
Get up to 40 % extra points for free! More info

Lesson 9 - Java Multithreading - Runnable, Callable, Future, Executor

In the previous lesson, Multithreading in Java - Barrier, CountDownLatch, we got familiar with the barrier. In today's tutorial, we're going to take a closer look at Runnable, Callable, and Future interfaces. We'll introduce their methods and differences. In the second part of the article we'll focus on the Executor interface. There will be no implementations in this lesson.

Runnable, Callable, and Future

These three interfaces are the basis of multithreading in Java.


We've already encountered the Runnable interface at the beginning when we were learning to create threads. One way to create a thread was through its constructor with a Runnable parameter. This interface contains only one method:

public interface Runnable {
  public void run();

The body of the run() method is executed on the thread and the thread terminates when it's done. This interface is perfect for some simple tasks, but it has one important drawback: if the thread was calculating something, there's no easy way to tell the "parent" that the calculation has finished (or failed). We'd have to use, for example, a semaphore or a barrier. The next interface tries to fix this problem.


This interface is generic, which means that we have to specify the data type in angle brackets when implementing it. This data type represents the result that the method will return once the "calculation" is completed:


...End of the preview...
Continue further

You will gain knowledge worth hundreds of thousands for a few crowns

You've come here and that's great! We believe that the first lessons showed you something new and useful
Do you want to continue the course? Go to the premium section.

Limited offer: Learn all knowledge and save money

Buy lessons and exercise submitting one by one 102 points
Buy all currently available lessons with exercise submitting and other features for an exclusive price 87 points ($7.83)
Currently, you have 0 points
By buying this exclusive package, you'll have access to all 13 lessons in this course including exercise submitting while saving $1.35. This offer is limited for the first lessons only with an additional exclusive 15% discount.
You gain 87 points for adding an article to the site, or for $9.18 $7.83

Warning, by buying just this lesson you'll lose the limited 15% discount for the package of all the lessons.

Buy only the lesson 10 points
Currently, you have 0 points
You gain 10 points for adding an article to the site, or for $0.90

This article is licensed: Premium, by buying this article, you agree with the terms of use.

What will you get from us in the next lessons?
  • Unlimited and permanent access to individual lessons.
  • High quality IT knowledge.
  • Skills to help you get your dream and well-paid job.

Article description

Requested article covers this content:

In this Java article we'll introduce advanced techniques for parallel programming. We'll describe the Runnable, Callable, Future and Executor interfaces.

You gain points by supporting our network. This is done by sending a helpful amount of money to support the site, or by creating content for the network.

Article has been written for you by Petr Štechmüller
Activities (4)