Book excerpt: Do you want to develop mobile apps with Java—and have them work on a variety of devices powered by iOS and Android? You’ve come to the right place. This project-driven book shows you how to build portable apps with two amazing open source frameworks, Google Web Tools (GWT) and PhoneGap. With these tools, you’ll use learn how to write Java code that compiles into cross-platform Javascript and HTML, and discover how to take advantage of features in several popular devices, such as the camera, accelerometer, and GPS. Get started with GWT by building an example Twitter search app Build a example web app and adapt it for mobile with CSS Add touch centric controls with the GWT Mobile UI library Develop a working wine journal app that tracks a user’s GPS location Use techniques to make a mobile version of your web or desktop app Work with HTML5 Canvas to build a mobile video game Package your apps for iOS, webOS, and Android with PhoneGap