How to Create Thread using Lambda Expressions in Java?
Last Updated :
01 Apr, 2022
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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:
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
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
import java.util.Random;
// This is a random player class with two functionalities
// playGames and playMusic
class 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
