Book Image

Learning Network Programming with Java

Book Image

Learning Network Programming with Java

Overview of this book

Network-aware applications are becoming more prevalent and play an ever-increasing role in the world today. Connecting and using an Internet-based service is a frequent requirement for many applications. Java provides numerous classes that have evolved over the years to meet evolving network needs. These range from low-level socket and IP-based approaches to those encapsulated in software services. This book explores how Java supports networks, starting with the basics and then advancing to more complex topics. An overview of each relevant network technology is presented followed by detailed examples of how to use Java to support these technologies. We start with the basics of networking and then explore how Java supports the development of client/server and peer-to-peer applications. The NIO packages are examined as well as multitasking and how network applications can address practical issues such as security. A discussion on networking concepts will put many network issues into perspective and let you focus on the appropriate technology for the problem at hand. The examples used will provide a good starting point to develop similar capabilities for many of your network needs
Table of Contents (16 chapters)
Learning Network Programming with Java
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface
Index

Java support for UDP


Java uses the DatagramSocket class to form socket connections between nodes. The DatagramPacket class represents a packet of data. Simple send and receive methods will transmit the packets across a network.

UDP uses an IP address and a port number to identify nodes. UDP port numbers range from 0 to 65535. Port numbers are broken down into three types:

  • Well-known ports (0 to 1023): These are port numbers that are used for relatively common services.

  • Registered ports (1024 to 49151): These are port numbers that are assigned by IANA to a process.

  • Dynamic/private ports (49152 to 65535): These are dynamically assigned to clients when a connection is initiated. These are normally temporary and cannot be assigned by IANA.

The following table is a short list of UDP specific port assignments. They illustrate how UDP is widely used to support many diverse applications and services. A more complete list of TCP/UDP port numbers is found at https://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers...