The world is becoming interconnected on an unprecedented scale with more services being provided on the Internet. Applications ranging from business transactions to embedded applications, such as those found in refrigerators, are connecting to the Internet. With isolated applications no longer being the norm, it is becoming increasingly important for applications to be network enabled.
The goal of this book is to provide the reader with the necessary skills to develop Java applications that connect and work with other applications and services across a network. You will be introduced to a wide range of networking options that are available using Java, which will enable you to develop applications using the appropriate technology for the task at hand.
Chapter 1, Getting Started with Network Programming, introduces the essential network terminology and concepts. The networking support that Java provides is illustrated with brief examples. A simple client/server application is presented along with a threaded version of the server.
Chapter 2, Network Addressing, explains how nodes on a network use addresses. How Java represents these addresses is introduced along with support for IPv4 and IPv6. This chapter also covers how Java can configure various network properties.
Chapter 3, NIO Support for Networking, explains how the NIO package provides support for communication using buffers and channels. These techniques are illustrated with a client/server application. The support that NIO provides for asynchronous communication is also demonstrated.
Chapter 4, Client/Server Development, covers how HTTP is an important and widely-used protocol. Java provides support for this protocol in a variety of ways. These techniques are illustrated along with a demonstration of how cookies are handled in Java.
Chapter 5, Peer-to-Peer Networks, discusses how peer-to-peer networks provide a flexible alternative to the traditional client/server architecture. The basic peer-to-peer concepts are introduced along with demonstrations of how Java supports this architecture. FreePastry is used to illustrate one open source peer-to-peer solution framework.
Chapter 6, UDP and Multicasting, explains how UDP is an alternative to TCP. It provides a less reliable but more efficient way for applications to communicate across the Internet. Java's extensive support for this protocol is demonstrated, including NIO support, and how UDP can support streaming media.
Chapter 7, Network Scalability, explains how, as more demands are placed on a server, systems need to scale to address these demands. Several threading techniques supporting this need are demonstrated, including thread pools, futures, and the NIO's selector.
Chapter 8, Network Security, discusses how applications need to protect against a variety of threats. This is supported in Java using encryption and secure hashing techniques. Symmetric and asymmetric encryption techniques are illustrated. In addition, the use of TLS/SSL is demonstrated.
Chapter 9, Network Interoperability, covers how Java applications may need to exchange information with other applications that are written in different languages. The issues that impact an application's interoperability are examined, including byte order. Communication between different implementations is demonstrated using sockets and middleware.
Java SDK 1.8 is needed for the network programming examples that are encountered in the book. An IDE, such as NetBeans or Eclipse, is recommended. NetBeans IDE 8.0.2 EE edition is used to illustrate the development of a web service.
This book is for developers who are already proficient in Java and want to learn how to develop network-enabled Java applications. Familiarity with basic Java and object-oriented programming concepts is all that is needed. You will learn the basics of network programming and how to use a multitude of different sockets to create secure and scalable applications.
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public class ThreadedEchoServer implements Runnable {
private static Socket clientSocket;
public ThreadedEchoServer(Socket clientSocket) {
this.clientSocket = clientSocket;
}
...
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