Posts tagged Web
JavaOne 2012: What’s new in Servlet3.1: An Overview
0Session at JavaOne come in various shapes. Some are visionary, high level and future oriented. Others are detailed and discuss practical, sometimes very fine grained topics. One of the sessions I attended was somewhere in between: future oriented yet pretty concrete at the same time. It was probably my favorite session at JavaOne this year: What’s new in Servlet3.1: An Overview by Shing Wai Cha and Rajiv Mordani. The passion of the presenters – their enthusiasm to explain the current development of the Servlet API and their ability to demonstrate some rather tough concepts were pivotal. Many presenters can take their style as an example they can learn from.
The Servlet 3.1 API is part of the JEE 7 edition- that is scheduled for complete release in April 2013. The Servlet Specification is largely complete, although some elements are still under discussion as became clear during this talk. The probably most important new requirement in Servlet 3.1 is the ability to do Web Socket interaction. Web Sockets is a relatively new communication protocol that runs over TCP/IP and goes beyond HTTP in several respects. Web Sockets support bi-directional interactions (open channels through More >
Publishing to CometD Bayeux Channel from inside the Oracle Database – PL/SQL based push to CometD Web Client
1In recent articles, I have introduced CometD as framework for Server to Client and Client to Client Push: Running CometD 2 examples – locally on Tomcat using Maven and NetBeans http://technology.amis.nl/blog/14709/running-cometd-2-examples-locally-on-tomcat-using-maven-and-netbeans, CometD 2 Java Client Sample – open project in NetBeans based on Maven pom file, modify sources and run Java Based Comet Client (http://technology.amis.nl/blog/14720/cometd-2-java-client-sample-open-project-in-netbeans-based-on-maven-pom-file-modify-sources-and-run-java-based-comet-client) and Push based synchronized Slideshow demo application implemented using CometD and jQuery running on Tomcat (http://technology.amis.nl/blog/14870/push-based-synchronized-slideshow-demo-application-implemented-using-cometd-and-jquery-running-on-tomcat).
CometD allows web clients (or stand alone Java clients) to subscribe to Bayeux channels maintained by the CometD Server (Servlet). These clients can publish messages to the channels and CometD will deliver the messages to all or to selected clients – in a push-fashion. This makes it possible to push messages from the Java server side of a web application to web More >
Push based synchronized Slideshow demo application implemented using CometD and jQuery running on Tomcat
2In a string of recent articles, I have discussed downloading, installing and running demos for a number of different tools, frameworks and libraries that support push-style (web) applications in one way or another. I have looked into ‘classic’ comet with Grizzly, Atmosphere and CometD as well as ADF Active Data Service and WebLogic Pub/Sub (Bayeux) Channels. I have also looked to WebSockets with jWebSocket, again Atmosphere and CometD and also with Kaazing. I am now working on a series of articles in which I use each of these frameworks and push infrastructures to implement the same simple push-style application – to see how that goes and to compare the various implementations. The functionality I will be implementing is simple:
- through the web client (HTML 5/javaScript), a user can select an image from a list of ’slides’
- the selection of the image is communicated to the server (background WebSocket based or alternatively regular AJAX)Comet (Bayeux)/Long Poll style)
- the server informs all connected clients about the selected image through a pushed message (background WebSocket based or alternatively Comet (Bayeux)/Long Poll style); these clients all synchronize that slide More >
Get going with Kaazing WebSocket Gateway – HTML5 Edition – installing locally and running demos
2My last few articles on this blog site have all dealt with push architecture and technology in some way. This is an area that I have been investigating into quite bit recently. Part of these investigations had to be of course Kaazing, a specialized commercial offering, specifcally around WebSockets and its application in new HTML 5 application architectures.
Kaazing suggests a new way of implementing multi-tier (web) applications.
Communication between client and back end services happens over WebSockets. The Kaazing Gateway handles all WebSockets communication, turning messages from various back end services based on technologies such RSS, XMPP, JMS into WebSocket events.
Kaazing supports a variety of clients – though HTML 5 (JavaScript) web clients (including those running on mobile devices) are probably the most prominent ones.
IETester: Develop and test your site for multiple versions of Internet Explorer
When developing or testing your web application, you often have to support different browsers and versions. On Window machines testing for different versions of Firefox, Opera and Chrome is not a real problem as these browsers all allow you to install different versions on one machine. Only Internet Explorer (IE) is always a bit more difficult, because it’s integrated in the OS (Windows) of the machine. This mostly ends up installing multiple IE versions on multiple (virtual) machines, which is not a nice way of working when developing. Can we do this different and easier? Yes, we can!
Update (4-4-2012): IETester now supports IE 5.5 up to IE 10!
Recent Comments