GWT is designed to enable Web application development with Java. Developers can benefit from Java's static typing and more rigidly structured architecture. It generates the requisite JavaScript code that is needed for the application's client-side components. GWT powers several high-profile Google Web applications, including Google Wave. The GWT developers implemented browser-based Quake by using a Java port of the Quake 2 engine on top of GWT.
GWT and the Java-based Quake engine both had to be extended and modified extensively in order for the pairing to work, but the effort paid off. It serves as a compelling example of how emerging standards are becoming increasingly capable of delivering all of the necessary functionality for interactive 3D network gaming.
As some readers might remember, Google released a Quake demo for Native Client (NaCl) when the plug-in was first announced in 2008. The state of open Web technologies has clearly advanced since that time. It's no longer necessary to rely on plugins to deliver this kind of functionality.
Source: Arstechnica.com