URL Understanding

URL is the acronym of Universal Resource Locator and it’s used to locate the server and resource. Every resource on the web has it’s own unique address. Let’s see parts of URL with an example.
http://localhost:8080/FirstServletProject/jsps/hello.jsp
http:// – This is the first part of URL and provides the communication protocol to be used in server-client communication.
localhost – The unique address of the server, most of the times it’s the hostname of the server that maps to unique IP address. Sometimes multiple hostnames point to same IP addresses and web server virtual host takes care of sending request to the particular server instance.
8080 – This is the port on which server is listening, it’s optional and if we don’t provide it in URL then request goes to the default port of the protocol. Port numbers 0 to 1023 are reserved ports for well known services, for example 80 for HTTP, 443 for HTTPS, 21 for FTP etc.
FirstServletProject/jsps/hello.jsp – Resource requested from server. It can be static html, pdf, JSP,
servlets, PHP etc.