This document provides code examples for implementing various networking and internet protocols in Java, including:
1. A protocol scanner that tests which protocols (HTTP, HTTPS, FTP, etc.) are supported for a given URL.
2. A port scanner that detects which ports on a given host are open or closed.
3. Code to download and parse an HTML page from a URL.
4. A knock-knock joke client-server application implementing a protocol to exchange jokes over a network.