A Servlet is the Java technology used to extend and improve Web server functionality. Servlets are able to provide a platform independent way to build web-based applications founded upon components without the performance limitations.
Servlets idea was propsed by James Gosling in 1995. Servlet API was developed by James Duncan Davidson with the first release of the Java Web Servlet Development Kit (JWSDK) in June of 1997, and the Java Servlet API 2.1. It was the first used Servlets with Sun´s Java Web Server to develop a website.
Java servlets are a key component of server-side Java development. A servlet is a small, pluggable extension to a server that enhances the server´s functionality. Servlets allow developers to extend and customize any Java-enabled server-a web server, a mail server, an application server, or any custom server-with a hitherto unknown degree of portability, flexibility, and ease.