Servlet technology was advancement in CGI introduced to overcome the shortcomings of Common-Gateway-Interface (CGI) technology for providing robustness and efficiency to the web applications.
The main advantages of the servelts over CGI are as follows:-
Servlets provide better performance that CGI in terms of processing time, memory utilization because servlets uses benefits of multithreading and for each request a new thread is created and same same memory utilize for each request , that is faster than loading creating new Object for each request with CGI.
Servlets and platform and system independent, the web application developed with Servlet can be run on any standard web container such as Tomcat, JBoss, Glassfish servers and on o perating systems such as Windows, Linux, Unix, Solaris, Mac etc.
Servlets are robust because container takes care of life cycle of servlet and we donít need to worry about memory leaks, security loophols, garbage collection etc.
Servlets are maintainable and east learning and implemant because all we need to take care is business logic for our application and the rest is managed by the servlet container.