Server-Sent Events (SSE) is part of HTML5. SSE is a simple, undirectional communication from server to browser. It allows server to push data to client once a connection is established. The entire point of SSE is to make it easy for the server to push messages to the browser, once the browser has first established a connection to the server.
Servlet 3.1 (JSR 340) is final and is part of Java EE 7. I and Rajiv had presented the session CON 4854, "What's New in JSR 340, Servlet 3.1?", on September 23 at JavaOne 2013, San Francisco. It was at 3:00pm. Most of the audiences are quite familiar with Servlet technology and we had a good Q&A during the talk.
javax.servlet.http.HttpSession provides a way to identify an user across multiple HTTP requests and to store user specified information. In other words, it provides a support of stateful communications with the stateless HTTP protocol.
Java API for WebSocket is a new JSR to Java EE 7. It provides a stardard Java API for creating WebSocket applications. This gives web applications the ability to push data.
Expression Language (EL) was first introduced as part of JSTL 1.0, was then moved JSP 2.0 and was unified with JSF 1.2 in JSP 2.1. In Java EE 7, EL is a new separate JSR, JSR 341. Many new features are introduced in EL 3.0.
This blog shows how to use new following new features of EL 3.0:
- Standalone environment
Update: In Servlet 3.0, the behavior of using response is undefined after invoking #complete or #dispatch. In Servlet 3.1, it is clarified that AsyncContext#getResponse will throw IllegalStateException. The blog has been updated for this.
Update: Invoke WebConnection#close when there is an error.
Servlet 3.1 Specification (JSR 340) is almost ready for the release. One of the new features is the support for protocol upgrade.
HTTP protocol upgrade was introduced in HTTP 1.1 (RFC 2616):
Servlet 3.1 Specification (JSR 340) and Java Authorization Contract for Containers (JSR 115) MR3 are almost ready for release. Besides "*", the role-name "**" is introduced in the above two specifications.