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Preface
1. The Problem
Nowadays we use general purpose applications or libraries to communicate with each other. For example,
we often use an HTTP client library to retrieve information from a web server and to invoke a remote
procedure call via web services.
However, a general purpose protocol or its implementation sometimes does not scale very well. It is like
we don't use a general purpose HTTP server to exchange huge files, e-mail messages, and near-realtime
messages such as financial information and multiplayer game data. What's required is a highly optimized
protocol implementation which is dedicated to a special purpose. For example, you might want to implement
an HTTP server which is optimized for AJAX-based chat application, media streaming, or large file transfer.
You could even want to design and implement a whole new protocol which is precisely tailored to your need.
Another inevitable case is when you have to deal with a legacy proprietary protocol to ensure the
interoperability with an old system. What matters in this case is how quickly we can implement that protocol
while not sacrificing the stability and performance of the resulting application.
2. The Solution
The Netty project is an effort to provide an asynchronous event-driven network application framework and
tooling for the rapid development of maintainable high-performance high-scalability protocol servers and
clients.
In other words, Netty is a NIO client server framework which enables quick and easy development of
network applications such as protocol servers and clients. It greatly simplifies and streamlines network
programming such as TCP and UDP socket server development.
'Quick and easy' does not mean that a resulting application will suffer from a maintainability or a
performance issue. Netty has been designed carefully with the experiences earned from the implementation
of a lot of protocols such as FTP, SMTP, HTTP, and various binary and text-based legacy protocols. As
a result, Netty has succeeded to find a way to achieve ease of development, performance, stability, and
flexibility without a compromise.
Some users might already have found other network application framework that claims to have the same
advantage, and you might want to ask what makes Netty so different from them. The answer is the
philosophy where it is built on. Netty is designed to give you the most comfortable experience both in terms
of the API and the implementation from the day one. It is not something tangible but you will realize that
this philosophy will make your life much easier as you read this guide and play with Netty.
