Intruduction
Server side java solves one problem that applets face. When the code is being executed on the server side there are no issues with browser compatibilities on long down load times. The java application on the server only sends the packets of information to the clients.  Java servlets are one of options for server side java development.
Servlets are generic extension to java enable servers has are very secure, portable and easer to use replacements for CGI.A Servlet is dynamically requests from a web server.

Applications for java Servlets:

1. Developing E-Commerce:-“Store Fonts”willl become one of the most common uses for java servlets.

2. Servelets can be used develop websites that open up large legacies system on internet.

3. When deploying as distributed objects application that will be deployed to the web.

Advantages of servlets:

1. Efficient:-Servlet initialization code is executed only the first time the web server loads it. After the servlets is loading and handling new request is only a matter of calling the service method.

2. Persistent:-Servlet can maintain state between rearest when a servlet is loaded it stays resident in memory while serving in coming request.

3. Portable:-servlet are developed using java there fore this are portable .This enables servlets to be moved to a new operating system with out changing the source.

4. Robust:-There are very powerful and robust solutions provide a very well determined exception hierarchy for error handling.

5. Extensable:-An Object oriented Language like java is these can be extended and polymorphic into new objects that better suits your needs.

6. Secure:-Servlet run on the server side inheriting the securities provided by the web server. Servlets can also take an advantage of the java securities manager.

7. Wide Spread Acceptance:-World widely most of the companies accepted java servlets.

Servlet Alternatives

1)CGI(Common Gateway Interface):-It is a common server side solution to develop web applications .It is an independent module that receives request from a web server and have same common problems for CGI are.
1. A Web server creates a new process every time it receives a request.
2. CGI code can be implemented in almost all languages. The most common plate form independent language is PERL(Partial Extraction Resource Language).
3. CGI runs in a completely separate process from the web server.

2) Proprietary API:-The most common examples API’s includes Netscape’s NSAPI, Microsoft’s ISAPI and orally web site API. The problems with these solutions are that they are proprietors .These API’s are developed in C or C++ languages can contain memory leaks. The Web Servers may crash.

3)Server side JavaScript:-Server side JavaScript another solution for implementing dynamic websites but the only servers tat implement server side java script is Netscape enterprise(NE5) and Fast Track Servers.

4) Microsoft Active server Pages:-Like server side JavaScript ‘ASP’ is also embedded into HTML pages but it is not precompiled .It is tide to a particular web server specifically Microsoft internet information server.

Some Popular Web servers To Run the Servlets:-
1. Appache web server (tomcat)
2. java web server
3. Weblogic
4. Java Server Development Kit(JSDK)
5. Java Server Web Development Kit(JSWDK)
6. NetScape Enterprise Server
7. WebSphere Application Server