Servlets

Servlets:

Servlets is a specification for developing web applications with Java programming language.

Web Application:

A web application is a distributed application which runs on browser & server.

Distributed Application:

An application that is installed on one computer and runs on many computers is called distributed application.

Application:

An application is a program in which we interact with on the desktop.

Browser:

A browser is a software that executes web pages containing text, image, graphics, animation, audio, video, .. etc.,

List of Browsers:

1) Internet Explorer

2) Netscape Navigator

3) Neo Planet

4) Hot Java

5) Eye Browse

6) Cyber Dog

7) America Online

8) Mozilla Firefox

9) Mosaic

10) Opera

11) Mac Web

12) Win Web

13) Lynx

14) Google Chrome

Browser is called as web client.

Client:

A client is a software that sends the request to server to get the response.

Server:

A server is a software that receives request from the client, process the request, constructs the response and sends the response back to a client.

Types of Servers:

1) Web Servers

2) Application Servers

1) Web Server:

A web server is a server which contains only web container

List of web servers:

1) Tomcat web server

2) Pramathi web server

3) iPlanet web server

4) Java web server

5) Personal web server

6) Jetty web server

7) Resin web server .. etc.,

2) Application Server:

An application server is a server which contains both web container & EJB container.

EJB stands for Enterprise Java Beans

List of Application Servers:

1) WebLogic Application Server

2) WebSphere Application Server

3) JBoss Application Server

4) Sun One Application Server

5) Glass Fish Application Server .. etc.,

Specification:

A specification is a set of rules & guidelines that are used to develop applications  & environments.

Servlets specification used by vendors to develop web containers.

Web container is a part web server & application server.

Servlets specification used by Java programmers to develop web applications.

There are two types of web applications:

1) Static Web Applications

2) Dynamic Web Applications

1) Static Web Applications:

A web application that is already prepared and placed in server is known as static web application.

Static web applications are common to all users.

Static web application resides in server & runs in browser.

The server sends the program to a browser whenever request comes to a static web application.

Static web applications can be developed by using HTML, CSS, Java Script, Applets, .. etc.,

HTML stands for Hyper Text Markup Language.

CSS stands for Cascading Style Sheets.

Applets are Java programs.

2) Dynamic Web Applications:

A web application that is prepared dynamically whenever request comes to a server is known as dynamic web application.

Dynamic web applications are specific to user.

Dynamic web application resides in server & runs in server only.

The server executes the program & sends the output to a browser whenever request comes to a dynamic web application.

Dynamic web applications can be developed by using Servlets, JSP, Struts, JSF, Spring MVC, PHP, CGI, ASP, .. etc.,

JSP stands for Java Server Pages.

JSF stands for Java Server Faces.

MVC stands for Model View Controller

PHP stands for Personal Home Page

CGI stands for Common Gateway Interface

ASP stands for Active Server Pages

Servlets, JSP, Struts, JSF & Spring MVC are Java programs.

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By

Mr. Venkatesh Mansani