Servlet Advantages and Disadvantages

Servlet Advantage

1.     Servlets provide a way to generate dynamic documents that is both easier to write and faster to run.

2.     provide all the powerfull features of JAVA, such as Exception handling and garbage collection.

3.     Servlet enables easy portability across Web Servers.

4.     Servlet can communicate with different servlet and servers.

5.     Since all web applications are stateless protocol, servlet uses its own API to maintain  session

Servlet Disadvantage

1.     Designing in servlet is difficult and slows down the application.

2.     Writing complex business logic makes the application difficult to understand.

3.     You need a Java Runtime Environment on the server to run servlets. CGI is a completely language independent protocol, so you can write CGIs in whatever languages you have available (including Java if you want to).

Advantages over CGI

The advantages of using Servlets are their fast performance and ease of use combined with more power over traditional CGI (Common Gateway Interface). Traditional CGI scripts written in Java have a number of disadvantages when it comes to performance:

• When an HTTP request is made, a new process is created for each call of the CGI script. This overhead of process creation can be very system-intensive, especially when the script does relatively fast operations. Thus, process creation will take more time than CGI script execution. Java Servlets solve this, as a Servlet is not a separate process. Each request to be handled by a Servlet is handled by a separate Java thread within the web server process.
• Simultaneous CGI request causes the CGI script to be copied and loaded into memory as many times as there are requests. However, with Servlets, there are the same amount of threads as requests, but there will only be one copy of the Servlet class created in memory that stays there also between requests.
• Only a single instance answers all requests concurrently. This reduces memory usage and makes the management of persistent data easy.
• A Servlet can be run by a Servlet container in a restrictive environment, called a sandbox. This is similar to an applet that runs in the sandbox of the web browser. This makes a restrictive use of potentially harmful Servlets possible.