# Introduction

![](https://2698670403-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-M3y20se5T5tgBXBcWyM%2F-M3y23Fq1q0Wn8xweQA9%2F-M3y26LTrmP_kd6EvKeX%2Fcover-with-border.JPG?generation=1585883942259774\&alt=media)

> ### Head over to [Leanpub](https://leanpub.com/java-websocket-api-handbook) to grab a PDF version of this book

The book is what it says it is - a handbook, a quick reference, a fast track guide. It covers the nitty gritty of the [**Java API for WebSocket**](https://jcp.org/en/jsr/detail?id=356): a Java based standard (specification) for building WebSocket based applications. As with most standard (Java) APIs, the WebSocket API has multiple (competing) implementations which comply with the specification. It is also a part of the [**Java EE Platform**](https://www.jcp.org/en/jsr/detail?id=342).

> What it implies is that you can use this standard API in a standalone format as well as part of a larger platform in concert with other Java EE based APIs such as JAX-RS, CDI, JPA, EJB, JMS etc.

## What's in the book ?

Let's look at a quick outline of book contents

The first three lessons are meant to get your **feet wet**

* [Warm up](https://github.com/abhirockzz/java-websocket-api-handbook/tree/d4615f44cb49e74da9f642c8b081e7ecd123ea12/Introduction.html)
* [API Overview](https://github.com/abhirockzz/java-websocket-api-handbook/tree/d4615f44cb49e74da9f642c8b081e7ecd123ea12/Exploring%20the%20API.html)
* [Programming Model](https://github.com/abhirockzz/java-websocket-api-handbook/tree/d4615f44cb49e74da9f642c8b081e7ecd123ea12/Programming%20Model.html)

Then comes the **core** part which is important from a API usage perspective

* [Sending Messages](https://github.com/abhirockzz/java-websocket-api-handbook/tree/d4615f44cb49e74da9f642c8b081e7ecd123ea12/Sending%20Messages.html)
* [Receiving Messages](https://github.com/abhirockzz/java-websocket-api-handbook/tree/d4615f44cb49e74da9f642c8b081e7ecd123ea12/Receiving%20Messages.html)
* [WebSocket Client API](https://github.com/abhirockzz/java-websocket-api-handbook/tree/d4615f44cb49e74da9f642c8b081e7ecd123ea12/websocket_client_api.html)

The default conventions offered by the WebSocket API can actually hide the details related to Configuration & Deployment, but you should know them anyway !

* [Configuration](https://github.com/abhirockzz/java-websocket-api-handbook/tree/d4615f44cb49e74da9f642c8b081e7ecd123ea12/configuration.html)
* [Deployment](https://github.com/abhirockzz/java-websocket-api-handbook/tree/d4615f44cb49e74da9f642c8b081e7ecd123ea12/deployment.html)

The book ends with a exploration of how the API integrates with other Java EE specifications as well as a quick peek into the threading details of some of the API constructs

* Tying in with the Java EE Platform: [Part I](https://github.com/abhirockzz/java-websocket-api-handbook/tree/d4615f44cb49e74da9f642c8b081e7ecd123ea12/part-1-tying_in_with_the_java_ee_platform.html) and [Part II](https://github.com/abhirockzz/java-websocket-api-handbook/tree/d4615f44cb49e74da9f642c8b081e7ecd123ea12/part-2-tying_in_with_the_java_ee_platform.html)
* [Lifecycle and Concurrency semantics](https://github.com/abhirockzz/java-websocket-api-handbook/tree/d4615f44cb49e74da9f642c8b081e7ecd123ea12/lifecycle_and_concurrency_semantics.html)

## Who is it suitable for ?

Although I would love for this book to be used by everyone, but, it is most suitable for Java/Java EE developers and can be used in various capacities

* As a 'getting started' with the Java WebSocket API guide
* You are well versed with the API and its constructs, but need a quick peek/reference to a specific API, it's usage, nuances etc.
* Maybe you're just curious about what Java has to offer in terms of WebSocket support - feel free to check this out

## What it is not ?

* a generic discourse on WebSocket: it deals with the Java implementation of the WebSocket specification (JSR-356 to be specific)
* a deep dive into the [WebSocket RFC](https://tools.ietf.org/html/rfc6455) itself
* exploration of other Java based WebSocket APIs/frameworks (e.g. Atmosphere etc.) is not the goal of this book