Java. Network Programming

Introduction

The book "Java Network Programming" (4th edition, 2013) by Elliotte Rusty Harold is a classic guide to developing network applications in Java. Despite being over a decade old, the book remains relevant for understanding the fundamental principles of networking in Java, especially in the context of classic APIs (java.net). The author, a renowned expert in Java and XML, offers a deep dive into sockets, URL, HTTP, UDP, and multithreading, without neglecting more modern topics such as NIO (New I/O).

The book is aimed at developers already familiar with the basics of Java and seeks to provide not just syntax, but an understanding of how network protocols work at the code level. It is not a reference manual, but a textbook with a large number of practical examples.

What the book is about

The book covers virtually all aspects of network programming in Java, starting from the very basics and ending with advanced topics. The main content is divided into logical blocks:

• Networking Basics: IP addresses, ports, TCP and UDP protocols, the OSI model. The author explains how Java abstracts these concepts.
• Working with URL and URI: The URL, URLConnection, HttpURLConnection classes. Parsing, creating, and handling links, working with HTTP requests and responses.
• TCP Sockets: The Socket and ServerSocket classes. Writing client-server applications, handling multiple clients, timeouts, buffering.
• UDP Sockets: The DatagramSocket and DatagramPacket classes. Sending and receiving datagrams, broadcasting.
• Multithreading in Networking: Creating multithreaded servers, thread pools, handling concurrent access to resources.
• NIO (New I/O): Channels, Buffers, Selectors. Non-blocking I/O for high-load systems.
• Security: SSL/TLS, authentication, encryption, working with secure connections.
• Application Layer Protocols: Examples of implementing simple HTTP clients, SMTP, POP3, FTP.

Who this book is for

The book will be useful for:

• Intermediate Java developers who want to deepen their knowledge of network communication.
• Students and novice programmers learning Java and wanting to understand how network applications work "from the inside."
• Developers transitioning from other languages (e.g., C++ or Python) to Java and needing to systematize their knowledge of network APIs.
• Software architects designing distributed systems and wanting to understand the intricacies of implementing network protocols in Java.

What the reader will learn

After reading the book, the reader will be able to:

• Confidently use the Socket and ServerSocket classes to create TCP clients and servers.
• Work with URLConnection and HttpURLConnection to perform HTTP requests (GET, POST, PUT, DELETE).
• Understand the difference between TCP and UDP and choose the appropriate protocol for a specific task.
• Implement multithreaded servers using thread pools and synchronization.
• Use Java NIO to create scalable non-blocking applications.
• Configure SSL/TLS for secure data exchange.
• Write their own implementations of simple protocols (e.g., an HTTP client without third-party libraries).
• Debug network applications and handle typical errors (timeouts, connection breaks).

Strengths

The book has a number of undeniable advantages:

• Depth and systematic approach: The author does not just list API methods, but explains why they work the way they do, often referencing RFCs and standards.