What is lambda expression in Java 9?

What is lambda expression in Java 9?

I'd be happy to explain Lambda Expressions in Java!

In Java, a Lambda Expression is a shorthand way of creating an instance of an anonymous class that implements a specific interface or abstract method. It was introduced in Java 8 and has been enhanced further in Java 9.

A Lambda Expression is typically used when you need to create a small, one-time-use function that performs a simple operation, such as filtering data, sorting objects, or processing a stream of elements. The syntax for a Lambda Expression is concise and expressive, making it easier to read and write code.

In its most basic form, a Lambda Expression consists of the following parts:

For example, consider a simple Lambda Expression that takes a string as input and returns its uppercase equivalent:

(String s) -> s.toUpperCase()

Here, (String s) is the parameter list (just one string in this case), -> separates it from the body of the function, and s.toUpperCase() is the code that gets executed when the Lambda Expression is called.

In Java 9, the Lambda Expressions got even more powerful with the addition of local variable type inference. This feature allows you to omit the type parameter in a Lambda Expression when the compiler can infer it from the context. For example:

(x) -> { System.out.println("Value: " + x); }

In this case, since x is being used as an integer (it's not explicitly declared), the compiler infers that x should be treated as an int. This simplifies your code and reduces the need for explicit type declarations.

Lambda Expressions are often used with functional programming concepts like streams, maps, filters, and reductions. They can help you write more concise and expressive code, making it easier to process and transform data.

Some of the key benefits of Lambda Expressions include:

In conclusion, Java's Lambda Expressions provide a powerful way to create small, one-time-use functions that can simplify your code and improve its readability. With the additional features in Java 9, you can write even more expressive and concise code!

Java lambda expressions w3schools

I'm happy to help you with that!

Java Lambda Expressions: A Beginner's Guide

Lambda expressions are a fundamental concept in Java programming, introduced in Java 8. They allow you to create anonymous functions and simplify your code by reducing the need for explicit classes and interfaces.

What is a Lambda Expression?

A lambda expression is an anonymous function that can be passed as an argument to methods, returned from methods, or stored in data structures. It's essentially a small, self-contained piece of code that takes one or more input parameters and returns a value.

The syntax for a lambda expression is:

(input parameters) -> { code }

Where:

Example: A Simple Lambda Expression

Here's an example of a simple lambda expression that takes one input parameter and returns its square:

(int x) -> x * x;

This lambda can be used with methods like stream().map() or Arrays.sort(), for instance.

Lambda Expressions vs. Anonymous Inner Classes

Before Java 8, you might have written anonymous inner classes to achieve similar results. For example:

(new Runnable() {
public void run() {
System.out.println("Hello World!");
}
}).run();

With lambda expressions, you can write the equivalent code in a much more concise way:

()-> System.out.println("Hello World!");

Advantages of Lambda Expressions

Common Use Cases for Lambda Expressions

Best Practices for Writing Lambda Expressions

Conclusion

Java lambda expressions are a powerful feature that simplifies your code and enables concise, expressive programming. By mastering lambda expressions, you'll improve your productivity, readability, and overall coding experience. W3Schools has an excellent resource on Java Lambda Expressions if you want to learn more!