Lambda Expressions are introduced in Java SE8. These expressions are developed for Functional Interfaces. A functional interface is an interface with only one abstract method. To know more about Lambda Expressions click here.
Syntax:
(argument1, argument2, .. argument n) -> {
// statements
};
Here we make use of the Runnable Interface. As it is a Functional Interface, Lambda expressions can be used. The following steps are performed to achieve the task:
- Create the Runnable interface reference and write the Lambda expression for the run() method.
- Create a Thread class object passing the above-created reference of the Runnable interface since the start() method is defined in the Thread class its object needs to be created.
- Invoke the start() method to run the thread.
Examples
Example 1:
Java
public class Test { public static void main(String[] args) { // Creating Lambda expression for run() method in // functional interface "Runnable" Runnable myThread = () -> { // Used to set custom name to the current thread Thread.currentThread().setName("myThread"); System.out.println( Thread.currentThread().getName() + " is running"); }; // Instantiating Thread class by passing Runnable // reference to Thread constructor Thread run = new Thread(myThread); // Starting the thread run.start(); }} |
Output
myThread is running
Example 2:
Multithreading-1 using lambda expressions
Java
public class Test { public static void main(String[] args) { Runnable basic = () -> { String threadName = Thread.currentThread().getName(); System.out.println("Running common task by " + threadName); }; // Instantiating two thread classes Thread thread1 = new Thread(basic); Thread thread2 = new Thread(basic); // Running two threads for the same task thread1.start(); thread2.start(); }} |
Output
Running common task by Thread-1 Running common task by Thread-0
Example 3:
Multithreading-2 using lambda expressions
Java
import java.util.Random;// This is a random player class with two functionalities// playGames and playMusicclass RandomPlayer { public void playGame(String gameName) throws InterruptedException { System.out.println(gameName + " game started"); // Assuming game is being played for 500 // milliseconds Thread.sleep(500); // this statement may throw // interrupted exception, so // throws declaration is added System.out.println(gameName + " game ended"); } public void playMusic(String trackName) throws InterruptedException { System.out.println(trackName + " track started"); // Assuming music is being played for 500 // milliseconds Thread.sleep(500); // this statement may throw // interrupted exception, so // throws declaration is added System.out.println(trackName + " track ended"); }}public class Test { // games and tracks arrays which are being used for // picking random items static String[] games = { "COD", "Prince Of Persia", "GTA-V5", "Valorant", "FIFA 22", "Fortnite" }; static String[] tracks = { "Believer", "Cradles", "Taki Taki", "Sorry", "Let Me Love You" }; public static void main(String[] args) { RandomPlayer player = new RandomPlayer(); // Instance of // RandomPlayer to access // its functionalities // Random class for choosing random items from above // arrays Random random = new Random(); // Creating two lambda expressions for runnable // interfaces Runnable gameRunner = () -> { try { player.playGame(games[random.nextInt( games.length)]); // Choosing game track // for playing } catch (InterruptedException e) { e.getMessage(); } }; Runnable musicPlayer = () -> { try { player.playMusic(tracks[random.nextInt( tracks.length)]); // Choosing random // music track for // playing } catch (InterruptedException e) { e.getMessage(); } }; // Instantiating two thread classes with runnable // references Thread game = new Thread(gameRunner); Thread music = new Thread(musicPlayer); // Starting two different threads game.start(); music.start(); /* *Note: As we are dealing with threads output may *differ every single time we run the program */ }} |
Output
Believer track started GTA-V5 game started Believer track ended GTA-V5 game ended
