Google I/O 2008: Resource Bundles and Linkers in GWT
As Joel Webber says, "The fastest HTTP requests are those which do not, in fact, occur." GWT really takes this principle to heart. It turns out that GWT's compilation process provides the perfect opportunity to smush, pack, tweak, and jimmy the various types of resources needed in an Ajax application. Image bundles can reduce the number of image fetches by an order of magnitude. Style injection can automatically minify your CSS and inline background images as "data:" URLs. The Gadget linker automatically creates a module XML file for your GWT-based Google Gadget, and the Gears linker extension automatically creates a Gears manifest so you easily run your GWT app offline.
Is there any optimization that GWT doesn't include? No, not really. So, come learn how to use these extremely powerful tools to build surpassingly fast Ajax apps.
Bob Vawter (Google)