Java Network Programming, 4th Edition

Chapter 1. Basic Network Concepts

Network programming is no longer the province of a few specialists. It has become a core part of every developer’s toolbox. Today, more programs are network aware than aren’t. Besides classic applications like email, web browsers, and remote login, most major applications have some level of networking built in. For example:

• Text editors like BBEdit save and open files directly from FTP servers.
• IDEs like Eclipse and IntelliJ IDEA communicate with source code repositories like GitHub and Sourceforge.
• Word processors like Microsoft Word open files from URLs.
• Antivirus programs like Norton AntiVirus check for new virus definitions by connecting to the vendor’s website every time the computer is started.
• Music players like Winamp and iTunes upload CD track lengths to CDDB and download the corresponding track titles.
• Gamers playing multiplayer first-person shooters like Halo gleefully frag each other in real time.
• Supermarket cash registers running IBM SurePOS ACE communicate with their store’s server in real time with each transaction. The server uploads its daily receipts to the chain’s central computers each night.
• Schedule applications like Microsoft Outlook automatically synchronize calendars among employees in a company.

Java was the first programming language designed from the ground up for network applications. Java was originally aimed at proprietary cable television networks rather than the Internet, but it’s always had the network foremost ...