Java 8 introduced powerful new features that have transformed how we write Java code, making it more efficient, expressive, and functional. In this blog, we’ll see few key features of Java 8, including lambdas, the Stream API and more. Whether you’re a beginner or an experienced developer, this guide will help you understand and leverage these updates to write cleaner, concise code.
Lambda Expressions λ
Lambda expressions are simple block of code which takes in parameter/s and return a value. They are similar to functions but they don't need a name and can be implemented in right in the body of a method. Lambda expressions are primarily used to implement functional interfaces, eliminating lengthy boilerplate code and strengthening readability.
Without Lambda Expressions
With Lambda Expressions
Functional Interfaces
A functional interface in Java is simply an interface with just one job — it has only one abstract method (a method without a body). Think of it as a blueprint for a single task
For example, if you had a functional interface called Printable, it might have one method, print, which defines how to print a text without specifying the details. When you want to use it, you just provide the details of what print should actually do (printing to console or writing to file).
Method References
Method references in Java 8 are like shortcuts that make your code cleaner and easier to read. Imagine you want to tell Java to run a specific method, but without actually calling it directly. Instead of writing out a full command, you can point to it with a "reference," which is kind of like an address pointing to the method.
Let's break down the main types of method references and how they work with examples:
1) Reference to a Static Method
Here, Test::displayMessage points to displayMessage method of Test class, which prints the content to console. It’s a shorthand, and Java knows to run Test.displayMessage() when you use print method
2) Reference to an Instance Method
Here, testObj::displayMessage points to displayMessage method of testObj object of Test class, which prints the content to console. It’s a shorthand, and Java knows to run testObj.displayMessage() when you use print method
3) Reference to Constructor
Here, Message::new is a constructor reference that matches the print(String msg) method of the Printable interface. When printable.print(...) is called, it triggers the constructor of the Message class with the provided message as an argument.
Stream API
The Stream API in Java 8 is a way to handle collections (like lists, sets, or arrays) more efficiently. Think of a stream as a series of data items that you can process one by one, without needing to change the original data. It’s especially useful when you want to filter, sort, or transform data in a list or collection.
A stream is like a “pipeline” that lets data pass through and be processed step-by-step. Imagine you have a list of words, and you want to find all words that start with “J”, make them uppercase, and then print them. A stream will let you do this in a few lines, without writing long loops.
Types of Stream Operations
- Intermediate operations (like filter, map, and sorted) don’t produce results right away but return a modified stream.
- Terminal operations (like forEach, collect, and reduce) produce the final result and end the stream.
Optional
In Java, if you try to use an object that’s null, you get a NullPointerException. This is one of the most common causes of errors in Java. Optional helps to avoid these errors by making it clear when a value might be absent. Instead of directly dealing with null, you work with an Optional object that either contains a value or is empty.
Here’s what’s happening:
- .isPresent() checks if there’s a value inside.
- .get() retrieves the value, but only if there’s one present, Throws NoSuchElementException - if no value is present
Default Methods
Before Java 8, if you wanted to add a new method to an interface, all the classes that implemented that interface had to provide their own version of that method. This could be a hassle, especially if you had a lot of classes. With default methods, you can add new methods to an interface without breaking existing code. Classes that implement the interface can simply use the default method as-is or choose to override it with their own version.
In the main method, we create an instance of InnerTest and call print on it, This will invoke the overridden print method in InnerTest, Since InnerTest2 did not override the print method, it will use the default implementation from the Printable interface
Output:
InnerTest:Hi, Welcome to the World of Java
Default Method: Hi, Welcome to the World of Java
The above is the detailed content of Java eatures Made Simple: A Quick Guide. For more information, please follow other related articles on the PHP Chinese website!

Start Spring using IntelliJIDEAUltimate version...

When using MyBatis-Plus or other ORM frameworks for database operations, it is often necessary to construct query conditions based on the attribute name of the entity class. If you manually every time...

Java...

How does the Redis caching solution realize the requirements of product ranking list? During the development process, we often need to deal with the requirements of rankings, such as displaying a...

Conversion of Java Objects and Arrays: In-depth discussion of the risks and correct methods of cast type conversion Many Java beginners will encounter the conversion of an object into an array...

Solutions to convert names to numbers to implement sorting In many application scenarios, users may need to sort in groups, especially in one...

Detailed explanation of the design of SKU and SPU tables on e-commerce platforms This article will discuss the database design issues of SKU and SPU in e-commerce platforms, especially how to deal with user-defined sales...

How to set the SpringBoot project default run configuration list in Idea using IntelliJ...


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

MantisBT
Mantis is an easy-to-deploy web-based defect tracking tool designed to aid in product defect tracking. It requires PHP, MySQL and a web server. Check out our demo and hosting services.

Dreamweaver Mac version
Visual web development tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

PhpStorm Mac version
The latest (2018.2.1) professional PHP integrated development tool

WebStorm Mac version
Useful JavaScript development tools