Lambda Expressions

Lecture 79:-  Lambda Expressions

Lambda expressions are a significant feature introduced in Java 8 that enables you to write more concise and expressive code, especially when working with functional interfaces. A lambda expression is essentially an anonymous function—a way to define a block of code that can be passed around as an argument to methods or assigned to variables.

The syntax of a lambda expression is as follows:

scssCopy code

(parameters) -> expression or statement block

Here's a breakdown of the components:

• (parameters): The list of parameters (if any) that the lambda expression takes. If the lambda takes no parameters, you can leave the parentheses empty. If there is only one parameter, you can omit the parentheses. For multiple parameters, separate them with commas.
• ->: The arrow operator, which separates the parameters from the body of the lambda expression.
• expression or statement block: The body of the lambda expression. It can be a single expression or a block of multiple statements enclosed in curly braces. The return value is automatically inferred based on the context.

Lambda expressions are most commonly used with functional interfaces. A functional interface is an interface that contains only one abstract method, often referred to as a functional method. Lambda expressions allow you to provide a concise implementation of this single abstract method.

Here's an example of using lambda expressions with a functional interface:

javaCopy code

import java.util.function.Predicate; public class LambdaExpressionExample {    public static void main(String[] args) {        // Example of a lambda expression with a functional interface        Predicate<Integer> isEven = n -> n % 2 == 0;        // Using the lambda expression        System.out.println(isEven.test(4)); // Output: true        System.out.println(isEven.test(5)); // Output: false    } }

In this example, we use the Predicate functional interface, which has a single abstract method called test(T t). We define a lambda expression n -> n % 2 == 0, which takes an integer n as a parameter and checks if it is even. The lambda expression is then assigned to the variable isEven.

Lambda expressions are particularly useful when working with streams, as they allow you to provide concise operations for filtering, mapping, and reducing data in a declarative and functional style.

Lambda expressions have significantly improved the readability and maintainability of Java code and have made it easier to work with functional programming concepts in the language.