Advantages of Servlets over CGI

• Servlets are server side components that provides a mechanism for developing server web applications  for server side.
• Earlier CGI was developed to provide server side Capabilities to the web applications, But due to its Performance, Scalability and Reusability  issues, Servlets are preferred.
• Java Servlets overcome all the issues of CGI ( Common Gateway Interface ).
• Servlets are built from ground up using Sun's Write one run anywhere technology, java servlets provide excellent framework for server side processing.
• Web Developers can create fast & efficient server side applications using java servlets and can run it on any web server which is servlet compatible.
• servlets run entirely inside the java Virtual Machine.
• since servlets runs on server side, it does not check for Browser Compatibility.

Servlets mainly have 5 Advantages over CGI, they are

1) Platform Independent

• Platform Independence plays a major in the field where there are numerous number of web servers available to choose from.
• Servlets are written entirely in java, due to which they are platform independent.
• Servlets can run on any servlet enabled web-server.

Ex: web applications developed in windows machine running java web server, can easily run the same on apache web server ( if Apache server is installed ), without any modification or compilation of code.

2) Performance

• Due to interpreted nature of java, programs written in java are slow. But java servlets run very fast. it is because the way servlets run on web server.
• For any program Initialization takes significant amount of time in its life cycle. But in case of servlets initialization takes place only once when it receives the first request & remains in memory till times out or server shuts down's.
• Once servlet is initialized & loaded, to handle a new request it simply creates a new thread and runs service method of servlet.
• In case of CGI scripts, always a new process should be created to serve a request.

3) Extensibility

• Servlets are developed in java which is robust, well-designed & Object oriented language which can be extended or polymorphed into a new object
•  java servlets take all java's advantages to provide the ideal solution.

 4) Safety

• Java provides very good safety feature's like Memory management, Exception handling etc.
• Servlets inherit all these features & had emerged as a very powerful web server extension.

5) Security

• Since servlets are server side Components, it inherits the security of server.
• Servlets are also benefited with java security manager, provided by web server.