**Course Title:** Comprehensive Java Programming: From Basics to Advanced Concepts **Section Title:** Multithreading and Concurrency in Java **Topic:** Using the `Runnable` interface and `Thread` class. --- ### Overview of Runnable Interface In Java, the `Runnable` interface is used to define a class that can be executed by a thread. It is a functional interface, meaning it has only one method, `run()`, which is called when a thread is started. #### Why Use Runnable? Using the `Runnable` interface provides a cleaner separation of concerns between the thread's execution logic and the thread management. It allows you to write methods that can be executed concurrently without having to extend the `Thread` class. ### Defining a Runnable To define a `Runnable`, you need to implement the `Runnable` interface and provide an implementation for the `run()` method. ```java public class MyRunnable implements Runnable { @Override public void run() { // Code to be executed by a thread System.out.println("Thread is running..."); } } ``` ### Creating and Starting a Thread To execute a `Runnable` instance, you need to create a `Thread` object and pass the `Runnable` instance to the `Thread` constructor. Then, you can start the thread by calling the `start()` method. ```java public class Main { public static void main(String[] args) { MyRunnable runnable = new MyRunnable(); Thread thread = new Thread(runnable); thread.start(); } } ``` ### Using Anonymous Inner Classes You can also use anonymous inner classes to define a `Runnable` instance. ```java public class Main { public static void main(String[] args) { Runnable runnable = new Runnable() { @Override public void run() { System.out.println("Thread is running..."); } }; Thread thread = new Thread(runnable); thread.start(); } } ``` ### Using Lambda Expressions In Java 8 and later, you can use lambda expressions to define a `Runnable` instance. ```java public class Main { public static void main(String[] args) { Runnable runnable = () -> System.out.println("Thread is running..."); Thread thread = new Thread(runnable); thread.start(); } } ``` ### Best Practices When using the `Runnable` interface and `Thread` class, keep the following best practices in mind: * Always start a thread by calling the `start()` method, not the `run()` method directly. * Use the `Thread` class to manage threads, and the `Runnable` interface to define thread execution logic. * Use anonymous inner classes or lambda expressions to define `Runnable` instances when possible. ### Key Concepts * The `Runnable` interface is used to define a class that can be executed by a thread. * The `run()` method is called when a thread is started. * Use the `Thread` class to create and manage threads. * Use anonymous inner classes or lambda expressions to define `Runnable` instances. ### Practical Takeaways * Define a `Runnable` instance to execute code concurrently without having to extend the `Thread` class. * Use the `Thread` class to create and manage threads. * Use anonymous inner classes or lambda expressions to define `Runnable` instances. ### Additional Resources For more information on the `Runnable` interface and `Thread` class, refer to the [Oracle Java Documentation](https://docs.oracle.com/javase/tutorial/essential/concurrency/runthread.html). ### What's Next In the next topic, we will cover [Concurrency Utilities in `java.util.concurrent` package](https://docs.oracle.com/javase/tutorial/essential/concurrency/executors.html). ### Leave a Comment If you have any questions or need help with understanding the topic, leave a comment below.