Easy Notes Of Java programming unit-5 @Computer Diploma

Description

Socket Overview

• Client/Server Model: A fundamental network architecture where a client requests a resource or service from a server.
• Reserved Sockets (Ports): Standardized port numbers (0-1023) reserved for specific applications and services, such as HTTP (port 80) and FTP (port 21).
• Proxy Servers: Intermediary servers that act as a gateway between a user’s computer and the internet, often used for security, privacy, or caching.
• Internet Addressing: The system used to identify devices on a network. The most common form is an IP address, which can be IPv4 (e.g., 192.168.1.1) or IPv6.

Java and the Net

• Networking Classes: Java provides a set of classes and interfaces in the java.net package to facilitate network programming.
• InetAddress: Represents an Internet Protocol (IP) address.
  • Factory Methods: Static methods like getByName() and getAllByName() are used to create InetAddress objects.
  • Instance Methods: Non-static methods like getHostName() and getHostAddress() retrieve information about the IP address.

TCP/IP and Datagrams

• TCP/IP Sockets:
  • Socket: A client-side class for creating a TCP connection to a server.
  • ServerSocket: A server-side class that waits for and accepts incoming TCP connections from clients.
• Datagrams:
  • DatagramSocket: A class used for sending and receiving UDP packets.
  • DatagramPacket: A class that represents a UDP packet, containing both data and addressing information.

URL Classes

• URL Class: Represents a Uniform Resource Locator, providing methods to parse and access the components of a URL (protocol, hostname, port, file).
• URLConnection Class: An abstract class used to represent a communication link to a URL, allowing you to read from and write to the resource identified by the URL.