Preface

What this book covers

This book takes an in-depth look at lambdas and their supporting features; things like functional interfaces and type inference.

After reading the book, you'll:

• Have an overview of new features in modern Java
• Understand lambdas in-depth, their background, syntax, implementation details and how and when to use them
• Understand the difference between functions to classes and why that's relevant to lambdas
• Understand the difference between lambdas and closures
• Appreciate the improvements to type inference that drive a lot of the new features
• Be able to use method references and understand scoping and "effectively final"
• Understand the differences in bytecode produced when using lambdas
• Be able to reason about exceptions and exception handling best practice when using lambdas

What you need for this book

The latest version of JDK and a text editor or IDE.

Who this book is for

Whether you're migrating legacy Java programs to a more modern Java style or building applications from scratch, this book will help you start to leverage the power of functional programming on the Java platform.

Conventions

In this book, you will find a number of text styles that distinguish between different kinds of information. Here are some examples of these styles and an explanation of their meaning.

Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: "This LISP expression evaluates to a function, that when applied will take a single argument, bind it to arg and then add 1 to it."

A block of code is set as follows:

void anonymousClass() {
    final Server server = new HttpServer();
    waitFor(new Condition() {
        @Override
        public Boolean isSatisfied() {
            return !server.isRunning();
        }
    });
}

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

void anonymousClass() {
    final Server server = new HttpServer();
    waitFor(new Condition() {
        @Override
        public Boolean isSatisfied() {
            return !server.isRunning();
        }
    });
}

New terms and important words are shown in bold. Words that you see on the screen, for example, in menus or dialog boxes, appear in the text like this: "In order to download new modules, we will go to Files | Settings | Project Name | Project Interpreter."

Note

Warnings or important notes appear in a box like this.

Tip

Tips and tricks appear like this.

Reader feedback

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Customer support

Now that you are the proud owner of a Packt book, we have a number of things to help you to get the most from your purchase.

Downloading the color images of this book

We also provide you with a PDF file that has color images of the screenshots/diagrams used in this book. The color images will help you better understand the changes in the output. You can download this file from https://www.packtpub.com/sites/default/files/downloads/LearningJavaLambdas_ColorImages.pdf.

Errata

Although we have taken every care to ensure the accuracy of our content, mistakes do happen. If you find a mistake in one of our books-maybe a mistake in the text or the code-we would be grateful if you could report this to us. By doing so, you can save other readers from frustration and help us improve subsequent versions of this book. If you find any errata, please report them by visiting http://www.packtpub.com/submit-errata, selecting your book, clicking on the Errata Submission Form link, and entering the details of your errata. Once your errata are verified, your submission will be accepted and the errata will be uploaded to our website or added to any list of existing errata under the Errata section of that title.

To view the previously submitted errata, go to https://www.packtpub.com/books/content/support and enter the name of the book in the search field. The required information will appear under the Errata section.

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Please contact us at copyright@packtpub.com with a link to the suspected pirated material.

We appreciate your help in protecting our authors and our ability to bring you valuable content.

Questions

If you have a problem with any aspect of this book, you can contact us at questions@packtpub.com, and we will do our best to address the problem.