Summary

In this lesson, the following has been discussed

Servlets are Java technology's answer to Common Gateway Interface (CGI) programming.

		Java servlets are more efficient, easier to use, more powerful, more portable, safer, and cheaper than
		traditional CGI and many alternative CGI-like technologies.

		Web container (also known as a Servlet container) is the component of a web server that is responsible for
		managing the lifecycle of servlets, mapping a URL to a particular servlet and ensuring that the URL
		requester has the correct access rights.

		Other functions of web container are Communications support, Lifecycle Management, Multithreading
		Support, Declarative Security and JSP Support.

		Deployment Descriptor (DD) is simple XML document that conform to the XML standard, it is used to
		configure the web application.

		The service() method is the main method to perform the actual task. The servlet container calls the service()
		method to handle requests coming from the client and to write the formatted response back to the client.

DO NOT override the service() method, instead, override doGet() or doPost() methods.

GET Asks to get the thing (resource / file) at the requested URL.

Summary

		POST Asks the server to accept the body info attached to the request, and give it to the thing at the
		requested URL It's like a fat GET... a GET with extra info sent with the request.

POST has a body, GET hasn't.

POST is secured.

GET can be bookmarked, POST cannot.

GET is idempotent, POST isn't.

		The servlet lifecycle is simple; there's only one main state-initialized. If the servlet isn't initialized, then
		it's either being initialized, being destroyed, or it simply does not exist.

Multiple concurrent requests result in multiple threads not multiple instances.