Search icon CANCEL
Subscription
0
Cart icon
Cart
Close icon
You have no products in your basket yet
Save more on your purchases!
Savings automatically calculated. No voucher code required
Arrow left icon
All Products
Best Sellers
New Releases
Books
Videos
Audiobooks
Learning Hub
Newsletters
Free Learning
Arrow right icon
Learning Java Lambdas
Learning Java Lambdas

Learning Java Lambdas: An in-depth look at one of the most important features of modern Java

By Toby Weston
$15.99 per month
Book Mar 2017 114 pages 1st Edition
eBook
$23.99
Print
$143.99
Subscription
$15.99 Monthly
eBook
$23.99
Print
$143.99
Subscription
$15.99 Monthly

What do you get with a Packt Subscription?

Free for first 7 days. $15.99 p/m after that. Cancel any time!
Product feature icon Unlimited ad-free access to the largest independent learning library in tech. Access this title and thousands more!
Product feature icon 50+ new titles added per month, including many first-to-market concepts and exclusive early access to books as they are being written.
Product feature icon Innovative learning tools, including AI book assistants, code context explainers, and text-to-speech.
Product feature icon Thousands of reference materials covering every tech concept you need to stay up to date.
Subscribe now
View plans & pricing
Table of content icon View table of contents Preview book icon Preview Book

Learning Java Lambdas

Chapter 1. Introduction

Welcome to Learning Java Lambdas.

Java underwent huge changes in it's version 8 release. A lot was driven by the perception that Java was becoming long in the tooth. To compete with modern, functional programming languages, Java 8 introduced functional programming constructs like lambdas to better support a more functional style.

This book offers a concise explanation of lambdas and various other features required to make them work in Java. As well as offering background, syntax and usage examples of lambdas, the book describes other related features, such as functional interfaces and type inference.

The road to modern Java


Java 8 was released on March 18, 2014, two years seven months after the previous release. It was plagued with delays and technical problems but when it finally came, it represented one of the biggest shifts in Java since Java 5.

The headliners were of course lambdas and a retrofit to support functional programming ideas. With languages such as Scala taking center stage and the modern trend towards functional programming, Java had to do something to keep up.

Although Java is not and never will be a pure functional programming language, the changes in Java 8 enabled developers to use functional idioms more easily than in previous versions. With discipline and experience, you can now get a lot of the benefits of functional programming without resorting to third-party libraries.

Modern Java features

To give you an idea of just how big a change Java 8 was, and why it ushered in a new, modern Java, here's a mostly complete list of the new features it introduced:

  • Lambda support.

  • The core APIs were updated to take advantage of lambdas, including the collection APIs and a new functional package to help build functional constructs.

  • Entirely new APIs were developed that use lambdas, things like the stream API which brought functional style processing of data. For example, functions like map and flatMap from the stream API enable a declarative way to process lists and move away from external iteration to internal iteration. This in turn allows the library vendors to worry about the details and optimize processing however they like. For example, Java now comes with a parallel way to process streams without bothering the developer with the details.

  • Minor changes to the core APIs; new helper methods were introduced for strings, collections, comparators, numbers and maths.

  • Some of the additions are changing the way that people code. For example, the Optional class will be familiar to some, and it enables a better way to deal with nulls.

  • There were various concurrency library improvements. Things like an improved concurrent hash map, completable futures, thread safe accumulators, an improved read write lock (called a StampedLock), an implementation of a work stealing thread pool and much more besides.

  • Support for adding static methods to interfaces.

  • Default methods (otherwise known as virtual extension or defender methods).

  • Type inference was improved and new constructs like functional interfaces and method references were introduced to better support lambdas.

  • An improved date and time API was introduced (similar to the popular Joda-time library).

  • The IO and NIO packages received welcome additions to enable working with IO streams using the new streams API.

  • Reflection and annotations were improved.

  • An entirely new JavaScript engine shipped with Java 8. Nashorn replaced Rhino, and was faster and had better support for ECMA-Script.

  • JVM improvements; the integration with JRocket was completed, creating a faster JVM.

  • The JVM dropped the idea of perm gen, instead using native OS memory for class metadata. This is a huge deal and provides better memory utilization.

  • The JRocket integration also brought Mission control (jmc) to the JDK as standard. It compliments JConsole and VisualVM with similar functionality but adds very inexpensive profiling.

  • Other miscellaneous improvements, like improvements to JavaFX, base64 encoding support and more.

Left arrow icon Right arrow icon

Key benefits

  • Take a deep dive into one of the single most important additions to modern Java
  • Master Java lambdas, and fully understand functions, classes, and scope.
  • Improve your programming skills, which will enable you to write cleaner and more dynamic code

Description

In this short book, we take an in-depth look at lambdas in Java, and their supporting features. The book covers essential topics, such as functional interfaces and type inference, and the key differences between lambdas and closures. You will learn about the background to functional programming and lambdas, before moving on to understanding the basic syntax of lambdas and what differentiates these anonymous functions from standard anonymous classes. Lastly, you'll learn how to invoke lambdas and look at the bytecode generated. After reading this book, you'll understand lambdas in depth, their background, syntax, implementation details, and how and when to use them. You'll also have a clear knowledge of the difference between functions and classes, and why that's relevant to lambdas. This knowledge will enable you to appreciate the improvements to type inference that drive a lot of the new features in modern Java, and will increase your understanding of method references and scoping.

What you will learn

• What a lambda is and how it differs from other Java features • How to use lambdas effectively in your own projects • The use of method references and advanced scoping • The difference between lambdas and closures • The differences in bytecode produced when using lambdas

Product Details

Country selected

Publication date : Mar 31, 2017
Length 114 pages
Edition : 1st Edition
Language : English
ISBN-13 : 9781787282087
Vendor :
Oracle
Category :

What do you get with a Packt Subscription?

Free for first 7 days. $15.99 p/m after that. Cancel any time!
Product feature icon Unlimited ad-free access to the largest independent learning library in tech. Access this title and thousands more!
Product feature icon 50+ new titles added per month, including many first-to-market concepts and exclusive early access to books as they are being written.
Product feature icon Innovative learning tools, including AI book assistants, code context explainers, and text-to-speech.
Product feature icon Thousands of reference materials covering every tech concept you need to stay up to date.
Subscribe now
View plans & pricing

Product Details


Publication date : Mar 31, 2017
Length 114 pages
Edition : 1st Edition
Language : English
ISBN-13 : 9781787282087
Vendor :
Oracle
Category :

Table of Contents

10 Chapters
Learning Java Lambdas Chevron down icon Chevron up icon
Credits Chevron down icon Chevron up icon
About the Author Chevron down icon Chevron up icon
www.PacktPub.com Chevron down icon Chevron up icon
Customer Feedback Chevron down icon Chevron up icon
Preface Chevron down icon Chevron up icon
1. Introduction Chevron down icon Chevron up icon
2. Lambdas Introduction Chevron down icon Chevron up icon
3. Lambdas in Depth Chevron down icon Chevron up icon
Bytecode Chevron down icon Chevron up icon

Customer reviews

Top Reviews
Rating distribution
Empty star icon Empty star icon Empty star icon Empty star icon Empty star icon 0
(0 Ratings)
5 star 0%
4 star 0%
3 star 0%
2 star 0%
1 star 0%
Top Reviews
No reviews found
Get free access to Packt library with over 7500+ books and video courses for 7 days!
Start Free Trial

FAQs

What is included in a Packt subscription? Chevron down icon Chevron up icon

A subscription provides you with full access to view all Packt and licnesed content online, this includes exclusive access to Early Access titles. Depending on the tier chosen you can also earn credits and discounts to use for owning content

How can I cancel my subscription? Chevron down icon Chevron up icon

To cancel your subscription with us simply go to the account page - found in the top right of the page or at https://subscription.packtpub.com/my-account/subscription - From here you will see the ‘cancel subscription’ button in the grey box with your subscription information in.

What are credits? Chevron down icon Chevron up icon

Credits can be earned from reading 40 section of any title within the payment cycle - a month starting from the day of subscription payment. You also earn a Credit every month if you subscribe to our annual or 18 month plans. Credits can be used to buy books DRM free, the same way that you would pay for a book. Your credits can be found in the subscription homepage - subscription.packtpub.com - clicking on ‘the my’ library dropdown and selecting ‘credits’.

What happens if an Early Access Course is cancelled? Chevron down icon Chevron up icon

Projects are rarely cancelled, but sometimes it's unavoidable. If an Early Access course is cancelled or excessively delayed, you can exchange your purchase for another course. For further details, please contact us here.

Where can I send feedback about an Early Access title? Chevron down icon Chevron up icon

If you have any feedback about the product you're reading, or Early Access in general, then please fill out a contact form here and we'll make sure the feedback gets to the right team. 

Can I download the code files for Early Access titles? Chevron down icon Chevron up icon

We try to ensure that all books in Early Access have code available to use, download, and fork on GitHub. This helps us be more agile in the development of the book, and helps keep the often changing code base of new versions and new technologies as up to date as possible. Unfortunately, however, there will be rare cases when it is not possible for us to have downloadable code samples available until publication.

When we publish the book, the code files will also be available to download from the Packt website.

How accurate is the publication date? Chevron down icon Chevron up icon

The publication date is as accurate as we can be at any point in the project. Unfortunately, delays can happen. Often those delays are out of our control, such as changes to the technology code base or delays in the tech release. We do our best to give you an accurate estimate of the publication date at any given time, and as more chapters are delivered, the more accurate the delivery date will become.

How will I know when new chapters are ready? Chevron down icon Chevron up icon

We'll let you know every time there has been an update to a course that you've bought in Early Access. You'll get an email to let you know there has been a new chapter, or a change to a previous chapter. The new chapters are automatically added to your account, so you can also check back there any time you're ready and download or read them online.

I am a Packt subscriber, do I get Early Access? Chevron down icon Chevron up icon

Yes, all Early Access content is fully available through your subscription. You will need to have a paid for or active trial subscription in order to access all titles.

How is Early Access delivered? Chevron down icon Chevron up icon

Early Access is currently only available as a PDF or through our online reader. As we make changes or add new chapters, the files in your Packt account will be updated so you can download them again or view them online immediately.

How do I buy Early Access content? Chevron down icon Chevron up icon

Early Access is a way of us getting our content to you quicker, but the method of buying the Early Access course is still the same. Just find the course you want to buy, go through the check-out steps, and you’ll get a confirmation email from us with information and a link to the relevant Early Access courses.

What is Early Access? Chevron down icon Chevron up icon

Keeping up to date with the latest technology is difficult; new versions, new frameworks, new techniques. This feature gives you a head-start to our content, as it's being created. With Early Access you'll receive each chapter as it's written, and get regular updates throughout the product's development, as well as the final course as soon as it's ready.We created Early Access as a means of giving you the information you need, as soon as it's available. As we go through the process of developing a course, 99% of it can be ready but we can't publish until that last 1% falls in to place. Early Access helps to unlock the potential of our content early, to help you start your learning when you need it most. You not only get access to every chapter as it's delivered, edited, and updated, but you'll also get the finalized, DRM-free product to download in any format you want when it's published. As a member of Packt, you'll also be eligible for our exclusive offers, including a free course every day, and discounts on new and popular titles.