Servlet 3.0 Features
In this section, you will learn about new features added in the Servlet 3.0 .
Java Servlet is a server-side web-based technology utilized for constructing dynamic web content for web-based applications. It broadens the potentiality of servers, which host web-based applications, through harnessing request-response programming model.
Versions History
In the early days of Java, Servlet's thought came into the mind of James Gosling but it didn't became reality until the release of Java Web Server product . The first Servlet API version 1.0 was released on June 1997. The latest released version of Servlet API until now, when i am writing this, is Servlet 3.0 .
| Version(Servlet API) | Platform | Released on |
| Servlet 1.0 | June 1997 | |
| Servlet 2.0 | JDK 1.1 | |
| Servlet 2.1 | Unspecified | November 1998 |
| Servlet 2.2 | J2EE 1.2 | August 1999 |
| Servlet 2.3 | J2EE 1.3 | August 2001 |
| Servlet 2.4 | J2EE 1.4 | November 2003 |
| Servlet 2.5 | JavaEE 5 | September 2005 |
| Servlet 3.0 | JavaEE 6 | December 2009 |
Key changes in Servlet 3.0
Given below the major changes in Servlet 3.0 :
- Annotations
- Pluggability and extensibility
- Asynchronous support
- Security enhancements
Detailed List of Changes in Servlet 3.0
Given below detailed list of changes in Servlet 3.0 as per the sequence of addition / elimination :
- The suspend / resume APIs are no longer present . They have been
replaced by startAsync and AsyncContext which now has
forward and complete methods.
- Annotation names have changed and there are only top level annotations.
The method level annotations for declaring the Servlet methods are no longer
being used.
- The rules for assembling web.xml from fragments and annotations
is added.
- Updated isAsyncStarted to return false once a dispatch to the
container or a call to complete is done from the async handler.
- Added ordering support for fragments.
- Added support for file upload.
- Added support for loading static resources and JSPs from JAR files that
are included in the META-INF/resources directory of the JAR file which is
then bundled in the WEB-INF/lib directory.
- Added programmatic login / logout support.
- Clarified welcome files.
- Re-factored some of the Async APIs - moved addAsyncListener to
AsyncContext and renamed it to addListener. Moved
setAsyncTimeout to AsyncContext and renamed it to
setTimeout.
- Clarified some of the semantics around concurrent access to the request
and response in async processing.
- Updated pluggability rules for resource reference elements.
- Added a new annotation - @ServletSecurity (and associated
annotation for the fields) for defining security .