JSP Application Components

JSP Application Components
A typical JSP application involves the following components: a browser for client access, a database for enterprise data and a web application server ("middle tier") where the application objects live.
Ø The browser communicates with the middle tier using HTTP (Hyper Text Transfer Protocol) which involves sending a request message to which the middle tier replies with a response message.
Ø A JSP is a file with some HTML and Java code that executes top to bottom. At runtime, it is compiled into a Java class which is actually a servlet.
Ø A servlet is a Java-based web application server extension program that implements a standard API.
Ø A servlet session is a mechanism for maintaining state between HTTP requests during a period of continuous interaction between a browser and a web application. A session may be initiated at any time by the application and terminated by the application, by the user closing the browser, or by a period of user inactivity. A session usually corresponds to an application login/logout cycle
Ø A JavaBean (or "bean" for short) is simply a reusable component that implements specific design patterns to make it easy for programmers and development tools to discover the object's properties and behavior.
Ø Any objects in the middle tier that communicate with the database use a JDBC (Java Database Connectivity) driver.

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