Java Runnable Interface

Introduction

The Java programming language provides built-in support for multithreaded programming. A thread in Java is a lightweight, independent unit of execution that consists of a set of instructions. This article will focus on the Runnable interface, which is a key component of Java's multithreading capabilities.

What is the Runnable Interface?

The Runnable interface is a functional interface in Java that represents a task to be executed concurrently by a thread. A functional interface is an interface that contains only one abstract method. In the case of Runnable, this method is run(), which takes no arguments and returns no value.

The Runnable interface looks like this:

@FunctionalInterface
public interface Runnable {
    public abstract void run();
}

Implementing the Runnable Interface

To create a new thread, you need to implement the run() method of the Runnable interface. Here's a basic example:

class MyRunnable implements Runnable {
    public void run(){
        // thread's tasks
    }
}

In the run() method, you should specify the task that you want the thread to execute.

Creating and Starting a Thread

After you've implemented the Runnable interface, you can create a new instance of the Thread class and pass your Runnable object to its constructor. Then, you can start the new thread by calling the start() method on the Thread object.

Here's how you do it:

MyRunnable myRunnable = new MyRunnable();
Thread thread = new Thread(myRunnable);
thread.start();

When the start() method is called, the Java Virtual Machine (JVM) calls the run() method of the Runnable object in a new thread of execution.

Note on the start() Method

Remember that you should always call the start() method to start a new thread, not the run() method. If you call the run() method directly, the code will be executed in the current thread, not in a new thread.

Conclusion

That's a basic introduction to the Runnable interface in Java. Through the Runnable interface, Java gives you the ability to perform multiple tasks simultaneously within a single program. This is a powerful feature that can help you create more efficient and responsive applications. However, multithreaded programming can also be complex and challenging, so it's important to understand the basics before you start writing multithreaded code.