https://en.wikipedia.org/wiki/Java_servlet
History
The Servlet1 specification was created by Sun Microsystems, with version 1.0 finalized in June 1997. Starting with version 2.3, the specification was developed under the Java Community Process. JSR 53 defined both the Servlet 2.3 and JavaServer Page 1.2 specifications. JSR 154 specifies the Servlet 2.4 and 2.5 specifications. As of June 9, 2015, the current version of the Servlet specification is 3.1.
In his blog on java.net, Sun veteran and GlassFish lead Jim Driscoll details the history of servlet technology.[4]James Gosling first thought of servlets in the early days of Java, but the concept did not become a product until Sun shipped the Java Web Server[clarify] product. This was before what is now the Java Platform, Enterprise Edition was made into a specification.
| Servlet API version | Released | Platform | Important Changes |
| Servlet 4.0 | Under development | Java EE 8 | HTTP/2 |
| Servlet 3.1 | May 2013 | Java EE 7 | Non-blocking I/O, HTTP protocol upgrade mechanism (WebSocket)[5] |
| Servlet 3.0 | December 2009 | Java EE 6, Java SE 6 | Pluggability, Ease of development, Async Servlet, Security, File Uploading |
| Servlet 2.5 | September 2005 | Java EE 5, Java SE 5 | Requires Java SE 5, supports annotation |
| Servlet 2.4 | November 2003 | J2EE 1.4, J2SE 1.3 | web.xml uses XML Schema |
| Servlet 2.3 | August 2001 | J2EE 1.3, J2SE 1.2 | Addition of Filter |
| Servlet 2.2 | August 1999 | J2EE 1.2, J2SE 1.2 | Becomes part of J2EE, introduced independent web applications in .war files |
| Servlet 2.1 | November 1998 | Unspecified | First official specification, added RequestDispatcher, ServletContext |
| Servlet 2.0 | JDK 1.1 | Part of Java Servlet Development Kit 2.0 | |
| Servlet 1.0 | June 1997 |