Java is a versatile programming language that offers powerful features for concurrent and parallel programming. Two important aspects of Java that facilitate efficient multi-threading are lambda expressions and multi-threading.

In this blog post, we will explore lambda expressions and how they can be used to write concise and efficient code for multi-threading in Java.

Table of Contents

• Introduction to Lambda Expressions
• Lambda Expressions in Multi-Threading
• Example Code
• Conclusion
• References

Introduction to Lambda Expressions

Lambda expressions were introduced in Java 8 as a way to simplify the syntax of anonymous inner classes. They provide a concise way to represent a functional interface, which is an interface with a single abstract method.

Lambda expressions have the following syntax:

(parameters) -> expression

or

(parameters) -> { statements; }

The parameters are optional if there are no parameters, and the parentheses can be omitted if there’s only one parameter.

Lambda expressions allow us to express functions as values, enabling functional programming in Java. They are especially useful when working with collections and when dealing with multi-threading.

Lambda Expressions in Multi-Threading

Multi-threading is the ability of a program to execute multiple threads simultaneously. In Java, multi-threading can be achieved by extending the Thread class or implementing the Runnable interface.

With lambda expressions, writing code for multi-threading becomes more concise and readable. Instead of defining anonymous inner classes for Runnable objects, we can directly pass lambda expressions as arguments.

Here is an example that demonstrates how lambda expressions can be used in multi-threading:

public class Main {
  public static void main(String[] args) {
    // Creating a new thread using lambda expression
    Thread thread = new Thread(() -> {
      for (int i = 0; i < 10; i++) {
        System.out.println("Hello from thread: " + Thread.currentThread().getId());
      }
    });

    // Starting the thread
    thread.start();
  }
}

In the above example, a new Thread object is created using a lambda expression. The lambda expression represents the Runnable interface’s run method. The thread then starts to execute the code within the lambda expression concurrently.

Example Code

For a more practical example, let’s consider a scenario where we need to perform a computationally intensive task on multiple threads using lambda expressions.

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class Main {
  public static void main(String[] args) {
    // Creating a thread pool with 4 threads
    ExecutorService executorService = Executors.newFixedThreadPool(4);

    // Submitting tasks to the thread pool using lambda expressions
    for (int i = 0; i < 10; i++) {
      final int taskId = i;
      executorService.submit(() -> {
        // Perform the computationally intensive task here
        System.out.println("Running task " + taskId + " on thread: " + Thread.currentThread().getId());
      });
    }

    // Shutting down the thread pool
    executorService.shutdown();
  }
}

In this example, we create a fixed-size thread pool using the Executors.newFixedThreadPool() method. We then submit tasks to the thread pool using lambda expressions. Each task is a lambda expression representing the Runnable interface’s run method.

The thread pool takes care of managing the threads and executing the tasks concurrently. Once all tasks are completed, we shut down the thread pool.

Conclusion

Lambda expressions in Java provide a concise and readable way to write code for multi-threading. They simplify the syntax of anonymous inner classes and enable functional programming.

By using lambda expressions, we can write more efficient and expressive code for multi-threading, leading to improved performance and scalability in Java applications.

Start leveraging the power of lambda expressions in your Java projects to take advantage of multi-threading capabilities and enhance the efficiency of your applications.

References

1. Lambda Expressions in Java - Oracle Documentation
2. Java Concurrency - Oracle Documentation