Google just announced it is removing the beta label from GWT:

‘Removing the beta lable from a product is a great milestone, and we’re glad to report that the latest one to make that move is the Google Web Toolkit (GWT).’

This new 1.4 release includes:

New widgets and libraries

* RichTextArea, HorizontalSplitPanel and VerticalSplitPanel,
SuggestBox, DisclosurePanel, PushButton, ToggleButton, and an
enhanced Image widget make advanced applications easier than ever.
* ImageBundle automatically consolidates multiple images into a
single HTTP request.
* NumberFormat and DateTimeFormat make easy work of complex
internationalization and localization.
* You can finally use java.lang.Serializable with GWT RPC, and the
GWT RPC server-side subsystem is no longer intimately tied to
servlets. You can easily wire it into any Java back-end
infrastructure. Spring fans, rejoice.
* A new JUnit-based benchmarking subsystem makes measuring and
comparing the speed of code snippets as easy as writing unit tests.

New deployment options and optimizations

* Adding GWT modules to an HTML page is now simple: just add a tag.
* You can now include GWT modules across domains. Note that including
scripts from other sites that you don’t fully trust is a big security
risk.

* External JavaScript files referenced from your GWT module load
synchronously now, so script ready-functions are no longer needed.
* Auto-generated RPC whitelist files are now produced during
compilation to help catch accidentally responding with objects that
compiled GWT client code wouldn’t be able to deserialize.
* The GWT distribution now includes a DTD for the GWT module XML
format, making it easier to configure modules in an DTD-aware XML
editor.