Back on June 6th I made a note of this post by Echo2 creator Tod Liebeck at The Server Side, entitled Comparing the Google Web Toolkit to Echo2, but never got around to blogging about it. Tod gives a fairly succinct description of both GWT and Echo2:
GWT’s defining attribute is the Java-to-JavaScript compiler. This compiler allows you to develop the web interface to your application in Java, then compile it to JavaScript. GWT limits the developer to a subset of the Java 1.4 libraries. GWT applications can be served by any web server, such as Apache, without the need for server-side processing.
Echo2 applications are compiled to Java byte code and run on a Java server. Their Java code is executed by Echo2′s “Web Application Container” layer, which sits atop a Java Servlet. On the web browser, the Echo2 “Client Engine” communicates user input to the Web Application Container via AJAX requests, with the server responding with directives to perform incremental updates to the state of the client web browser.
He goes on to analyze other points of comparison, including architectural, performance and legal issues. A good comparison by one of the AJAX worlds leading developers.
One thought here is that many folks have held out a GWT as a tool for writing widgets for other frameworks such as ZK and Echo2. I’ve been going through the Javascript infrastructure of GWT and it seems there’s a whole lot of plumbing that stands in the way of making this a reality. More on this later.
