In our previous post on the GWT Web Toolkit, we discussed the strengths and characteristics of GWT to mix Java and JavaScript libraries seamlessly in the browser. In today's post, we would like to go a little deeper and see the GWT Toolkit in action. We'll demonstrate how we can take advantage of GWT to build a peculiar application: an augmented reality web application that runs in real time, fully in JavaScript, in the browser. We'll focus on how GWT gives us the ability to interact easily with many JavaScript APIs, such as WebRTC and WebGL, and allows us to harness a large Java library, NyARToolkit, never intended to be used in the browser.